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Zheng J, Baimoukhametova D, Lebel C, Bains JS, Kurrasch DM. Hypothalamic vasopressin sex differentiation is observed by embryonic day 15 in mice and is disrupted by the xenoestrogen bisphenol A. Proc Natl Acad Sci U S A 2024; 121:e2313207121. [PMID: 38753512 PMCID: PMC11126957 DOI: 10.1073/pnas.2313207121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 03/19/2024] [Indexed: 05/18/2024] Open
Abstract
Arginine vasopressin (AVP) neurons of the hypothalamic paraventricular region (AVPPVN) mediate sex-biased social behaviors across most species, including mammals. In mice, neural sex differences are thought to be established during a critical window around birth ( embryonic (E) day 18 to postnatal (P) day 2) whereby circulating testosterone from the fetal testis is converted to estrogen in sex-dimorphic brain regions. Here, we found that AVPPVN neurons are sexually dimorphic by E15.5, prior to this critical window, and that gestational bisphenol A (BPA) exposure permanently masculinized female AVPPVN neuronal numbers, projections, and electrophysiological properties, causing them to display male-like phenotypes into adulthood. Moreover, we showed that nearly twice as many neurons that became AVP+ by P0 were born at E11 in males and BPA-exposed females compared to control females, suggesting that AVPPVN neuronal masculinization occurs between E11 and P0. We further narrowed this sensitive period to around the timing of neurogenesis by demonstrating that exogenous estrogen exposure from E14.5 to E15.5 masculinized female AVPPVN neuronal numbers, whereas a pan-estrogen receptor antagonist exposed from E13.5 to E15.5 blocked masculinization of males. Finally, we showed that restricting BPA exposure to E7.5-E15.5 caused adult females to display increased social dominance over control females, consistent with an acquisition of male-like behaviors. Our study reveals an E11.5 to E15.5 window of estrogen sensitivity impacting AVPPVN sex differentiation, which is impacted by prenatal BPA exposure.
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Affiliation(s)
- Jing Zheng
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, CalgaryT2N 1N4, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, CalgaryT2N 1N4, Canada
- Hotchkiss Brain Institute, University of Calgary, CalgaryT2N 1N4, Canada
| | - Dinara Baimoukhametova
- Hotchkiss Brain Institute, University of Calgary, CalgaryT2N 1N4, Canada
- Department of Physiology and Pharmacology, University of Calgary, CalgaryT2N 1N4, Canada
| | - Catherine Lebel
- Alberta Children’s Hospital Research Institute, University of Calgary, CalgaryT2N 1N4, Canada
- Hotchkiss Brain Institute, University of Calgary, CalgaryT2N 1N4, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, CalgaryT2N 1N4, Canada
| | - Jaideep S. Bains
- Hotchkiss Brain Institute, University of Calgary, CalgaryT2N 1N4, Canada
- Department of Physiology and Pharmacology, University of Calgary, CalgaryT2N 1N4, Canada
| | - Deborah M. Kurrasch
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, CalgaryT2N 1N4, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, CalgaryT2N 1N4, Canada
- Hotchkiss Brain Institute, University of Calgary, CalgaryT2N 1N4, Canada
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Li H, Jiang T, An S, Xu M, Gou L, Ren B, Shi X, Wang X, Yan J, Yuan J, Xu X, Wu QF, Luo Q, Gong H, Bian WJ, Li A, Yu X. Single-neuron projectomes of mouse paraventricular hypothalamic nucleus oxytocin neurons reveal mutually exclusive projection patterns. Neuron 2024; 112:1081-1099.e7. [PMID: 38290516 DOI: 10.1016/j.neuron.2023.12.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 11/07/2023] [Accepted: 12/29/2023] [Indexed: 02/01/2024]
Abstract
Oxytocin (OXT) plays important roles in autonomic control and behavioral modulation. However, it is unknown how the projection patterns of OXT neurons align with underlying physiological functions. Here, we present the reconstructed single-neuron, whole-brain projectomes of 264 OXT neurons of the mouse paraventricular hypothalamic nucleus (PVH) at submicron resolution. These neurons hierarchically clustered into two groups, with distinct morphological and transcriptional characteristics and mutually exclusive projection patterns. Cluster 1 (177 neurons) axons terminated exclusively in the median eminence (ME) and have few collaterals terminating within hypothalamic regions. By contrast, cluster 2 (87 neurons) sent wide-spread axons to multiple brain regions, but excluding ME. Dendritic arbors of OXT neurons also extended outside of the PVH, suggesting capability to sense signals and modulate target regions. These single-neuron resolution observations reveal distinct OXT subpopulations, provide comprehensive analysis of their morphology, and lay the structural foundation for better understanding the functional heterogeneity of OXT neurons.
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Affiliation(s)
- Humingzhu Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; School of Life Sciences, Peking-Tsinghua Center for Life Sciences, and Peking University McGovern Institute, Peking University, Beijing 100871, China
| | - Tao Jiang
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou 215123, China
| | - Sile An
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Mingrui Xu
- University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lingfeng Gou
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Biyu Ren
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaoxue Shi
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaofei Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jun Yan
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Yuan
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou 215123, China; Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaohong Xu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qing-Feng Wu
- University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qingming Luo
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou 215123, China; Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hui Gong
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou 215123, China; Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wen-Jie Bian
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, China; School of Life Sciences, Westlake University, Hangzhou 310024, China.
| | - Anan Li
- HUST-Suzhou Institute for Brainsmatics, JITRI, Suzhou 215123, China; Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Xiang Yu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; School of Life Sciences, Peking-Tsinghua Center for Life Sciences, and Peking University McGovern Institute, Peking University, Beijing 100871, China; Chinese Institute for Brain Research, Beijing 102206, China.
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3
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Keller BN, Snyder AE, Coker CR, Aguilar EA, O’Brien MK, Bingaman SS, Arnold AC, Hajnal A, Silberman Y. Vagus nerve damage increases alcohol intake and preference in a nonpreferring rat line: Relationship to vagal regulation of the hypothalamic-pituitary-adrenal axis. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2024; 48:488-498. [PMID: 38311347 PMCID: PMC10939901 DOI: 10.1111/acer.15264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/12/2023] [Accepted: 12/28/2023] [Indexed: 02/10/2024]
Abstract
BACKGROUND Clinical and preclinical research indicates that gastric weight loss surgeries, such as Roux-en-Y gastric bypass surgery, can induce alcohol use disorder (AUD). While numerous mechanisms have been proposed for these effects, one relatively unexplored potential mechanism is physical damage to the gastric branch of the vagus nerve, which can occur during bypass surgery. Therefore, we hypothesized that direct damage to the gastric branch of the vagus nerve, without altering other aspects of gastric anatomy, could result in increased alcohol intake. METHODS To test this hypothesis, we compared alcohol intake and preference in multiple models in male Sprague-Dawley rats that received selective gastric branch vagotomy (VX) with rats who underwent sham surgery. Because the vagus nerve regulates hypothalamic-pituitary-adrenal (HPA) axis function, and alterations to HPA function are critical to the escalation of non-dependent alcohol intake, we also tested the hypothesis that gastric VX increases HPA function. RESULTS We found that VX increases alcohol intake and preference in the every-other-day, two-bottle choice test and increases preference for 1 g/kg alcohol in the conditioned place preference test. The effects were selective for alcohol, as sucrose intake and preference were not altered by VX. We also found that VX increases corticotropin releasing factor (CRF) mRNA in the paraventricular nucleus of the hypothalamus (PVN), increases putative PVN CRF neuronal action potential firing, and increases corticosterone levels. CONCLUSIONS Overall, these findings suggest that the vagus nerve may play a critical role in regulating HPA axis function via modulation of PVN CRF mRNA expression and putative PVN CRF neuronal activity. Furthermore, disruptions to vagal regulation of HPA axis function may increase alcohol intake and preference.
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Affiliation(s)
- Bailey N. Keller
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Angela E. Snyder
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Caitlin R. Coker
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Elizabeth A. Aguilar
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Mary K. O’Brien
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Sarah S. Bingaman
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Amy C. Arnold
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Andras Hajnal
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
| | - Yuval Silberman
- The Pennsylvania State University College of Medicine, Department of Neural and Behavioral Sciences
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Yamaguchi J, Andrade MA, Truong TT, Toney GM. Glutamate Spillover Dynamically Strengthens Gabaergic Synaptic Inhibition of the Hypothalamic Paraventricular Nucleus. J Neurosci 2024; 44:e1851222023. [PMID: 38154957 PMCID: PMC10869154 DOI: 10.1523/jneurosci.1851-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/16/2023] [Accepted: 12/20/2023] [Indexed: 12/30/2023] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) is strongly inhibited by γ-aminobutyric acid (GABA) from the surrounding peri-nuclear zone (PNZ). Because glutamate mediates fast excitatory transmission and is substrate for GABA synthesis, we tested its capacity to dynamically strengthen GABA inhibition. In PVN slices from male mice, bath glutamate applied during ionotropic glutamate receptor blockade increased PNZ-evoked inhibitory postsynaptic currents (eIPSCs) without affecting GABA-A receptor agonist currents or single-channel conductance, implicating a presynaptic mechanism(s). Consistent with this interpretation, bath glutamate failed to strengthen IPSCs during pharmacological saturation of GABA-A receptors. Presynaptic analyses revealed that glutamate did not affect paired-pulse ratio, peak eIPSC variability, GABA vesicle recycling speed, or readily releasable pool (RRP) size. Notably, glutamate-GABA strengthening (GGS) was unaffected by metabotropic glutamate receptor blockade and graded external Ca2+ when normalized to baseline amplitude. GGS was prevented by pan- but not glial-specific inhibition of glutamate uptake and by inhibition of glutamic acid decarboxylase (GAD), indicating reliance on glutamate uptake by neuronal excitatory amino acid transporter 3 (EAAT3) and enzymatic conversion of glutamate to GABA. EAAT3 immunoreactivity was strongly localized to presumptive PVN GABA terminals. High bath K+ also induced GGS, which was prevented by glutamate vesicle depletion, indicating that synaptic glutamate release strengthens PVN GABA inhibition. GGS suppressed PVN cell firing, indicating its functional significance. In sum, PVN GGS buffers neuronal excitation by apparent "over-filling" of vesicles with GABA synthesized from synaptically released glutamate. We posit that GGS protects against sustained PVN excitation and excitotoxicity while potentially aiding stress adaptation and habituation.
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Affiliation(s)
- Junya Yamaguchi
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
| | - Mary Ann Andrade
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
| | - Tamara T Truong
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
| | - Glenn M Toney
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
- Center for Biomedical Neuroscience, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
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5
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Sato T, Sugaya T, Talukder AH, Tsushima Y, Sasaki S, Uchida K, Sato T, Ikoma Y, Sakimura K, Fukuda A, Matsui K, Itoi K. Dual action of serotonin on local excitatory and inhibitory neural circuits regulating the corticotropin-releasing factor neurons in the paraventricular nucleus of the hypothalamus. J Neuroendocrinol 2023; 35:e13351. [PMID: 37901949 DOI: 10.1111/jne.13351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 10/31/2023]
Abstract
Serotonergic neurons originating from the raphe nuclei have been proposed to regulate corticotropin-releasing factor (CRF) neurons in the paraventricular nucleus of the hypothalamus (PVH). Since glutamate- and γ-aminobutyric acid (GABA)-containing neurons, constituting the hypothalamic local circuits, innervate PVH CRF neurons, we examined whether they mediate the actions of serotonin (5-hydroxytryptamine [5-HT]) on CRF neurons. Spontaneous excitatory postsynaptic currents (sEPSCs) or spontaneous inhibitory postsynaptic currents (sIPSCs) were recorded in PVH CRF neurons, under whole cell patch-clamp, using the CRF-modified yellow fluorescent protein (Venus) ΔNeo mouse. Serotonin elicited an increase in the frequency of sEPSCs in 77% of the cells and a decrease in the frequency of sIPSCs in 71% of the cells, tested in normal medium. Neither the amplitude nor decay time of sEPSC and sIPSC was affected, thus the site(s) of action of serotonin may be presynaptic. In the presence of tetrodotoxin (TTX), serotonin had no significant effects on either parameter of sEPSC or sIPSC, indicating that the effects of serotonin are action potential-dependent, and that the presynaptic interneurons are largely intact within the slice; distant neurons may exist, though, since some 20%-30% of neurons did not respond to serotonin without TTX. We next examined through what receptor subtype(s) serotonin exerts its effects on presynaptic interneurons. DOI (5-HT2A/2C agonist) mimicked the action of serotonin on the sIPSCs, and the serotonin-induced decrease in sIPSC frequency was inhibited by a selective 5-HT2C antagonist RS102221. 8-OH-DPAT (5-HT1A/7 agonist) mimicked the action of serotonin on the sEPSCs, and the serotonin-induced increase in sEPSC frequency was inhibited by a selective 5-HT7 antagonist SB269970. Thus, serotonin showed a dual action on PVH CRF neurons, by upregulating glutamatergic- and downregulating GABAergic interneurons; the former may partly be mediated by 5-HT7 receptors, whereas the latter by 5-HT2C receptors. The CRF-Venus ΔNeo mouse was useful for the electrophysiological examination.
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Affiliation(s)
- Takayuki Sato
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Takuma Sugaya
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Ashraf Hossain Talukder
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Yuki Tsushima
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Shotaro Sasaki
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Katsuya Uchida
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Tatsuya Sato
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | - Yoko Ikoma
- Super-Network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Atsuo Fukuda
- Department of Physiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Ko Matsui
- Super-Network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Keiichi Itoi
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Japan
- Super-Network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- Department of Neuroendocrinology, Graduate School of Medicine, Tohoku University, Sendai, Japan
- Department of Nursing, Tohoku Fukushi University, Sendai, Japan
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6
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Althammer F. Heralding a new era of oxytocinergic research: New tools, new problems? J Neuroendocrinol 2023; 35:e13333. [PMID: 37621199 DOI: 10.1111/jne.13333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/10/2023] [Accepted: 08/10/2023] [Indexed: 08/26/2023]
Abstract
According to classic neuroendocrinology, hypothalamic oxytocin cells can be categorized into parvo- and magnocellular neurons. However, research in the last decade provided ample evidence that this black-and-white model of oxytocin neurons is most likely oversimplified. Novel genetic, functional and morphological studies indicate that oxytocin neurons might be organized in functional modules and suggest the existence of five or more distinct oxytocinergic subpopulations. However, many of these novel, automated high-throughput techniques might be inherently biased and interpretation of acquired data needs to be approached with caution to enable drawing sound and reliable conclusions. In addition, the recent finding that astrocytes in various brain regions express functional oxytocin receptors represents a paradigm shift and challenges the view that oxytocin primarily acts as a direct peptidergic neurotransmitter. This review highlights the latest technical advances in oxytocinergic research, puts recent studies on the oxytocin system into context and formulates various provocative ideas based on novel findings that challenges various prevailing hypotheses and dogmas about oxytocinergic modulation.
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Affiliation(s)
- Ferdinand Althammer
- Institute of Human Genetics, Heidelberg University Hospital, Heidelberg, Germany
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7
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Qian T, Wang H, Wang P, Geng L, Mei L, Osakada T, Wang L, Tang Y, Kania A, Grinevich V, Stoop R, Lin D, Luo M, Li Y. A genetically encoded sensor measures temporal oxytocin release from different neuronal compartments. Nat Biotechnol 2023; 41:944-957. [PMID: 36593404 PMCID: PMC11182738 DOI: 10.1038/s41587-022-01561-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 10/12/2022] [Indexed: 01/03/2023]
Abstract
Oxytocin (OT), a peptide hormone and neuromodulator, is involved in diverse physiological and pathophysiological processes in the central nervous system and the periphery. However, the regulation and functional sequences of spatial OT release in the brain remain poorly understood. We describe a genetically encoded G-protein-coupled receptor activation-based (GRAB) OT sensor called GRABOT1.0. In contrast to previous methods, GRABOT1.0 enables imaging of OT release ex vivo and in vivo with suitable sensitivity, specificity and spatiotemporal resolution. Using this sensor, we visualize stimulation-induced OT release from specific neuronal compartments in mouse brain slices and discover that N-type calcium channels predominantly mediate axonal OT release, whereas L-type calcium channels mediate somatodendritic OT release. We identify differences in the fusion machinery of OT release for axon terminals versus somata and dendrites. Finally, we measure OT dynamics in various brain regions in mice during male courtship behavior. Thus, GRABOT1.0 provides insights into the role of compartmental OT release in physiological and behavioral functions.
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Affiliation(s)
- Tongrui Qian
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Huan Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Peng Wang
- Medical Center for Human Reproduction, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Lan Geng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Long Mei
- Neuroscience Institute, Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA
| | - Takuya Osakada
- Neuroscience Institute, Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA
| | - Lei Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Peking University, Beijing, China
| | - Yan Tang
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital Center (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Alan Kania
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ron Stoop
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital Center (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Dayu Lin
- Neuroscience Institute, Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA
| | - Minmin Luo
- National Institute of Biological Sciences (NIBS), Beijing, China
- Chinese Institute for Brain Research, Beijing, China
- Tsinghua Institute of Multidisciplinary Biomedical Research (TIMBR), Tsinghua University, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China.
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China.
- Chinese Institute for Brain Research, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- National Biomedical Imaging Center, Peking University, Beijing, China.
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8
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Molinas AJR, Desmoulins LD, Davis RK, Gao H, Satou R, Derbenev AV, Zsombok A. High-Fat Diet Modulates the Excitability of Neurons within the Brain-Liver Pathway. Cells 2023; 12:1194. [PMID: 37190103 PMCID: PMC10137256 DOI: 10.3390/cells12081194] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/14/2023] [Accepted: 04/16/2023] [Indexed: 05/17/2023] Open
Abstract
Stimulation of hepatic sympathetic nerves increases glucose production and glycogenolysis. Activity of pre-sympathetic neurons in the paraventricular nucleus (PVN) of the hypothalamus and in the ventrolateral and ventromedial medulla (VLM/VMM) largely influence the sympathetic output. Increased activity of the sympathetic nervous system (SNS) plays a role in the development and progression of metabolic diseases; however, despite the importance of the central circuits, the excitability of pre-sympathetic liver-related neurons remains to be determined. Here, we tested the hypothesis that the activity of liver-related neurons in the PVN and VLM/VMM is altered in diet-induced obese mice, as well as their response to insulin. Patch-clamp recordings were conducted from liver-related PVN neurons, VLM-projecting PVN neurons, and pre-sympathetic liver-related neurons in the ventral brainstem. Our data demonstrate that the excitability of liver-related PVN neurons increased in high-fat diet (HFD)-fed mice compared to mice fed with control diet. Insulin receptor expression was detected in a population of liver-related neurons, and insulin suppressed the firing activity of liver-related PVN and pre-sympathetic VLM/VMM neurons in HFD mice; however, it did not affect VLM-projecting liver-related PVN neurons. These findings further suggest that HFD alters the excitability of pre-autonomic neurons as well as their response to insulin.
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Affiliation(s)
- Adrien J. R. Molinas
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Lucie D. Desmoulins
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Roslyn K. Davis
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Hong Gao
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Ryousuke Satou
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
| | - Andrei V. Derbenev
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
- Tulane Brain Institute, Tulane University, New Orleans, LA 70130, USA
| | - Andrea Zsombok
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA 70130, USA; (A.J.R.M.); (L.D.D.); (R.K.D.); (R.S.); (A.V.D.)
- Tulane Brain Institute, Tulane University, New Orleans, LA 70130, USA
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9
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Jiang Y, Rezai-Zadeh K, Desmoulins LD, Muenzberg H, Derbenev AV, Zsombok A. GABAergic leptin receptor-expressing neurons in the dorsomedial hypothalamus project to brown adipose tissue-related neurons in the paraventricular nucleus of mice. Auton Neurosci 2023; 245:103058. [PMID: 36538864 PMCID: PMC9899324 DOI: 10.1016/j.autneu.2022.103058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 11/14/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022]
Abstract
Brown adipose tissue (BAT) contributes to energy homeostasis via nonshivering thermogenesis. The BAT is densely innervated by the sympathetic nervous system (SNS) and activity of pre-autonomic neurons modulates the sympathetic outflow. Leptin, an adipocyte hormone, alters energy homeostasis and thermogenesis of BAT via several neuronal circuits; however, the cellular effects of leptin on interscapular BAT (iBAT)-related neurons in the hypothalamus remain to be determined. In this study, we used pseudorabies virus (PRV) to identify iBAT-related neurons in the paraventricular nucleus (PVN) of the hypothalamus and test the hypothesis that iBAT-related PVN neurons are modulated by leptin. Inoculation of iBAT with PRV in leptin receptor reporter mice (Lepr:EGFP) demonstrated that a population of iBAT-related PVN neurons expresses Lepr receptors. Our electrophysiological findings revealed that leptin application caused hyperpolarization in some of iBAT-related PVN neurons. Bath application of leptin also modulated excitatory and inhibitory neurotransmission to most of iBAT-related PVN neurons. Using channel rhodopsin assisted circuit mapping we found that GABAergic and glutamatergic Lepr-expressing neurons in the dorsomedial hypothalamus/dorsal hypothalamic area (dDMH/DHA) project to PVN neurons; however, connected iBAT-related PVN neurons receive exclusively inhibitory signals from Lepr-expressing dDMH/DHA neurons.
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Affiliation(s)
- Yanyan Jiang
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, United States of America; Neuroscience Program, Tulane Brain Institute, Tulane University, New Orleans, LA, United States of America
| | - Kavon Rezai-Zadeh
- Central Leptin Signaling, Pennington Biomedical Research Center, LSU System, Baton Rouge, LA, United States of America
| | - Lucie D Desmoulins
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, United States of America
| | - Heike Muenzberg
- Central Leptin Signaling, Pennington Biomedical Research Center, LSU System, Baton Rouge, LA, United States of America
| | - Andrei V Derbenev
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, United States of America; Neuroscience Program, Tulane Brain Institute, Tulane University, New Orleans, LA, United States of America
| | - Andrea Zsombok
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, United States of America; Neuroscience Program, Tulane Brain Institute, Tulane University, New Orleans, LA, United States of America.
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10
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Ugartemendia L, De Guzman RM, Cai J, Rajamanickam S, Jiang Z, Tao J, Zuloaga DG, Justice NJ. A subpopulation of oxytocin neurons initiate expression of CRF receptor 1 (CRFR1) in females post parturition. Psychoneuroendocrinology 2022; 145:105918. [PMID: 36116320 PMCID: PMC9881188 DOI: 10.1016/j.psyneuen.2022.105918] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/02/2022] [Accepted: 09/04/2022] [Indexed: 02/06/2023]
Abstract
Oxytocin (OT) is essential for successful reproduction, particularly during parturition and lactation. During the postpartum period, OT also influences maternal behavior to promote bonding between mothers and their newborns, and increases stress resilience. However, the mechanism by which stress influences OT neuron activity and OT release has remained unclear. Here, we provide evidence that a subpopulation of OT neurons initiate expression of the receptor for the stress neuropeptide Corticotropin Releasing Factor (CRF), CRFR1, in reproductive females. OT neuron expression of CRFR1 begins at the first parturition and increases during the postpartum period until weaning. The percentage of OT neurons that express CRFR1 increases with successive breeding cycles until it reaches a plateau of 20-25% of OT neurons. OT neuron expression of CRFR1 in reproductive females is maintained after they are no longer actively breeding. CRFR1 expression leads to activation of OT neurons when animals are stressed. We propose a model in which direct CRF signaling to OT neurons selectively in reproductive females potentiates OT release to promote stress resilience in mothers.
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Affiliation(s)
- Lierni Ugartemendia
- Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Sciences Center, Houston, TX 77030, United States
| | - Rose M De Guzman
- Department of Psychology, University at Albany, Albany, NY 12222, United States
| | - Jing Cai
- Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Sciences Center, Houston, TX 77030, United States
| | - Shivakumar Rajamanickam
- Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Sciences Center, Houston, TX 77030, United States
| | - Zhiying Jiang
- Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Sciences Center, Houston, TX 77030, United States
| | - Jonathan Tao
- Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Sciences Center, Houston, TX 77030, United States
| | - Damian G Zuloaga
- Department of Psychology, University at Albany, Albany, NY 12222, United States.
| | - Nicholas J Justice
- Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Sciences Center, Houston, TX 77030, United States.
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11
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Herrera Moro Chao D, Kirchner MK, Pham C, Foppen E, Denis RGP, Castel J, Morel C, Montalban E, Hassouna R, Bui LC, Renault J, Mouffle C, García-Cáceres C, Tschöp MH, Li D, Martin C, Stern JE, Luquet SH. Hypothalamic astrocytes control systemic glucose metabolism and energy balance. Cell Metab 2022; 34:1532-1547.e6. [PMID: 36198294 PMCID: PMC9615252 DOI: 10.1016/j.cmet.2022.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/23/2022] [Accepted: 09/02/2022] [Indexed: 01/29/2023]
Abstract
The hypothalamus is key in the control of energy balance. However, strategies targeting hypothalamic neurons have failed to provide viable options to treat most metabolic diseases. Conversely, the role of astrocytes in systemic metabolic control has remained largely unexplored. Here, we show that obesity promotes anatomically restricted remodeling of hypothalamic astrocyte activity. In the paraventricular nucleus (PVN) of the hypothalamus, chemogenetic manipulation of astrocytes results in bidirectional control of neighboring neuron activity, autonomic outflow, glucose metabolism, and energy balance. This process recruits a mechanism involving the astrocytic control of ambient glutamate levels, which becomes defective in obesity. Positive or negative chemogenetic manipulation of PVN astrocyte Ca2+ signals, respectively, worsens or improves metabolic status of diet-induced obese mice. Collectively, these findings highlight a yet unappreciated role for astrocytes in the direct control of systemic metabolism and suggest potential targets for anti-obesity strategy.
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Affiliation(s)
| | - Matthew K Kirchner
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA; Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA 30302, USA
| | - Cuong Pham
- Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, Sorbonne Universite, Paris 75005, France
| | - Ewout Foppen
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Raphael G P Denis
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France; Institut Cochin, Université Paris Cité, INSERM U1016, CNRS UMR 8104, 75014 Paris, France
| | - Julien Castel
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Chloe Morel
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Enrica Montalban
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Rim Hassouna
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Linh-Chi Bui
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Justine Renault
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Christine Mouffle
- Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, Sorbonne Universite, Paris 75005, France
| | - Cristina García-Cáceres
- Helmholtz Diabetes Center (HDC) & German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, 85764, Germany; Division of Metabolic Diseases, Technische Universität München, Munich, 80333, Germany; Medizinische Klinik and Poliklinik IV, Klinikum der Universität, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Matthias H Tschöp
- Helmholtz Diabetes Center (HDC) & German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, 85764, Germany; Division of Metabolic Diseases, Technische Universität München, Munich, 80333, Germany
| | - Dongdong Li
- Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, Sorbonne Universite, Paris 75005, France
| | - Claire Martin
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Javier E Stern
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA; Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA 30302, USA
| | - Serge H Luquet
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France.
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12
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Munier JJ, Marty VN, Spigelman I. Sex differences in α-adrenergic receptor function contribute to impaired hypothalamic metaplasticity following chronic intermittent ethanol exposure. Alcohol Clin Exp Res 2022; 46:1384-1396. [PMID: 35791038 PMCID: PMC9612407 DOI: 10.1111/acer.14900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/03/2022] [Accepted: 06/23/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND Individuals with alcohol use disorder (AUD) exhibit maladaptive responses of the hypothalamic-pituitary-adrenal (HPA) axis to stress, which has been linked to high rates of relapse to drinking among abstinent individuals. Corticotropin-releasing factor (CRF) parvocellular neuroendocrine cells (PNCs) within the paraventricular nucleus of the hypothalamus (PVN) are critical to stress-induced HPA axis activation. Here, we investigate sex differences in synaptic transmission and plasticity in PNCs following the application of the stress-associated neurotransmitter norepinephrine (NE) in a rat model of AUD. METHODS Adult Sprague-Dawley rats were exposed to 40 days of chronic intermittent ethanol (CIE) vapor and 30 to 108 days of protracted withdrawal. We measured changes in holding current, evoked synaptic currents, and short-term glutamatergic plasticity (STP) in putative PNCs following the application of NE (10 μM) with and without the selective α1 adrenergic receptor (AR) antagonist prazosin (10 μM) or the α2AR antagonist atipamezole (10 μM). The experiments were performed using whole-cell patch clamp recordings in slices from CIE rats and air-exposed controls. RESULTS NE application caused two distinct effects: a depolarizing, inward, postsynaptic current and a reduction in amplitude of an evoked glutamatergic excitatory postsynaptic current (eEPSC). Both effects were sex- and CIE-specific. Prazosin blocked the postsynaptic inward current, while atipamezole blocked the NE-mediated suppression of eEPSCs. Additionally, STP formation was facilitated following NE application only in stress-naïve males and this response was lost in stressed animals exposed to a 30-min restraint stress following CIE exposure. Furthermore, NE + prazosin restored STP formation in stressed CIE males. CONCLUSIONS NE exerts excitatory and inhibitory effects on CRF PVN PNCs, and both effects are influenced by sex and CIE. Behavioral and hormonal responses to stress are influenced by STP formation within the PVN, which is lost following CIE and restored with the preapplication of prazosin. The selective blockade of α1AR may, therefore, ameliorate CIE-induced deficits in HPA responses to stress in a sex-specific manner.
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Affiliation(s)
- Joseph J. Munier
- Department of Molecular, Cellular, and Integrative Physiology, University of California, Los Angeles, CA, USA,Laboratory of Neuropharmacology, Section of Biosystems and Function, School of Dentistry, University of California, Los Angeles, CA, USA
| | - Vincent N. Marty
- Laboratory of Neuropharmacology, Section of Biosystems and Function, School of Dentistry, University of California, Los Angeles, CA, USA
| | - Igor Spigelman
- Laboratory of Neuropharmacology, Section of Biosystems and Function, School of Dentistry, University of California, Los Angeles, CA, USA
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13
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Bi Q, Wang C, Cheng G, Chen N, Wei B, Liu X, Li L, Lu C, He J, Weng Y, Yin C, Lin Y, Wan S, Zhao L, Xu J, Wang Y, Gu Y, Shen XZ, Shi P. Microglia-derived PDGFB promotes neuronal potassium currents to suppress basal sympathetic tonicity and limit hypertension. Immunity 2022; 55:1466-1482.e9. [PMID: 35863346 DOI: 10.1016/j.immuni.2022.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/05/2022] [Accepted: 06/22/2022] [Indexed: 12/18/2022]
Abstract
Although many studies have addressed the regulatory circuits affecting neuronal activities, local non-synaptic mechanisms that determine neuronal excitability remain unclear. Here, we found that microglia prevented overactivation of pre-sympathetic neurons in the hypothalamic paraventricular nucleus (PVN) at steady state. Microglia constitutively released platelet-derived growth factor (PDGF) B, which signaled via PDGFRα on neuronal cells and promoted their expression of Kv4.3, a key subunit that conducts potassium currents. Ablation of microglia, conditional deletion of microglial PDGFB, or suppression of neuronal PDGFRα expression in the PVN elevated the excitability of pre-sympathetic neurons and sympathetic outflow, resulting in a profound autonomic dysfunction. Disruption of the PDGFBMG-Kv4.3Neuron pathway predisposed mice to develop hypertension, whereas central supplementation of exogenous PDGFB suppressed pressor response when mice were under hypertensive insult. Our results point to a non-immune action of resident microglia in maintaining the balance of sympathetic outflow, which is important in preventing cardiovascular diseases.
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Affiliation(s)
- Qianqian Bi
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Chao Wang
- Center of Stem Cell and Regenerative Medicine and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Science & Brain-Machine Integration, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Guo Cheng
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Ningting Chen
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Bo Wei
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiaoli Liu
- Department of Neurology, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Li Li
- Department of Pharmacy, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310013, China
| | - Cheng Lu
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jian He
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yuancheng Weng
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Chunyou Yin
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yunfan Lin
- Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Haining, Zhejiang 314400, China
| | - Shu Wan
- Brain Center, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Li Zhao
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jiaxi Xu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shanxi 710061, China
| | - Yi Wang
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yan Gu
- Center of Stem Cell and Regenerative Medicine and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Science & Brain-Machine Integration, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| | - Xiao Z Shen
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
| | - Peng Shi
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
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14
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Roy RK, Ferreira-Neto HC, Felder RB, Stern JE. Angiotensin II inhibits the A-type K + current of hypothalamic paraventricular nucleus neurons in rats with heart failure: role of MAPK-ERK1/2 signaling. Am J Physiol Regul Integr Comp Physiol 2022; 322:R526-R534. [PMID: 35319903 PMCID: PMC9076419 DOI: 10.1152/ajpregu.00308.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/03/2022] [Accepted: 03/18/2022] [Indexed: 11/22/2022]
Abstract
Angiotensin II (ANG II)-mediated sympathohumoral activation constitutes a pathophysiological mechanism in heart failure (HF). Although the hypothalamic paraventricular nucleus (PVN) is a major site mediating ANG II effects in HF, the precise mechanisms by which ANG II influences sympathohumoral outflow from the PVN remain unknown. ANG II activates the ubiquitous intracellular MAPK signaling cascades, and recent studies revealed a key role for ERK1/2 MAPK signaling in ANG II-mediated sympathoexcitation in HF rats. Importantly, ERK1/2 was reported to inhibit the transient outward potassium current (IA) in hippocampal neurons. Given that IA is a critical determinant of the PVN neuronal excitability, and that downregulation of IA in the brain has been reported in cardiovascular disease states, including HF, we investigated here whether ANG II modulates IA in PVN neurons via the MAPK-ERK pathway, and, whether these effects are altered in HF rats. Patch-clamp recordings from identified magnocellular neurosecretory neurons (MNNs) and presympathetic (PS) PVN neurons revealed that ANG II inhibited IA in both PVN neuronal types, both in sham and HF rats. Importantly, ANG II effects were blocked by inhibiting MAPK-ERK signaling as well as by inhibiting epidermal growth factor receptor (EGFR), a gateway to MAPK-ERK signaling. Although no differences in basal IA magnitude were found between sham and HF rats under normal conditions, MAPK-ERK blockade resulted in significantly larger IA in both PVN neuronal types in HF rats. Taken together, our studies show that ANG II-induced ERK1/2 activity inhibits IA, an effect expected to increase the excitability of presympathetic and neuroendocrine PVN neurons, contributing in turn to the neurohumoral overactivity that promotes progression of the HF syndrome.
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Affiliation(s)
- Ranjan K Roy
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | | | - Robert B Felder
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Javier E Stern
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
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15
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Clerc N, Moqrich A. Diverse roles and modulations of I A in spinal cord pain circuits. Cell Rep 2022; 38:110588. [PMID: 35354022 DOI: 10.1016/j.celrep.2022.110588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/25/2022] [Accepted: 03/08/2022] [Indexed: 11/03/2022] Open
Abstract
This review highlights recent findings of different amplitude ranges, roles, and modulations of A-type K+ currents (IA) in excitatory (GAD67-GFP-) and inhibitory (GAD67-GFP+) interneurons in mouse spinal cord pain pathways. Endogenous neuropeptides, such as TAFA4, oxytocin, and dynorphin in particular, have been reported to modulate IA in these pain pathways, but only TAFA4 has been shown to fully reverse the opposing modulations that occur selectively in LIIo GAD67-GFP- and LIIi GAD67-GFP+ interneurons following both neuropathic and inflammatory pain. If, as hypothesized here, Kv4 subunits underlie IA in both GAD67-GFP- and GAD67-GFP+ interneurons, then IA diversity in spinal cord pain pathways may depend on the interneuron-subtype-selective expression of Kv4 auxiliary subunits with functionally different N-terminal variants. Thus, IA emerges as a good candidate for explaining the mechanisms underlying injury-induced mechanical hypersensitivity.
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Affiliation(s)
- Nadine Clerc
- Aix-Marseille-Université, CNRS, Institut de Biologie du Développement de Marseille, UMR 7288, Case 907, 13288 Marseille Cedex 09, France.
| | - Aziz Moqrich
- Aix-Marseille-Université, CNRS, Institut de Biologie du Développement de Marseille, UMR 7288, Case 907, 13288 Marseille Cedex 09, France
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16
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Zhu X, Li K, Gao Y. Adeno-associated virus-mediated in vivo suppression of expression of EPHX2 gene modulates the activity of paraventricular nucleus neurons in spontaneously hypertensive rats. Biochem Biophys Res Commun 2022; 606:121-127. [PMID: 35344709 DOI: 10.1016/j.bbrc.2022.03.084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 03/16/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Hypertension can be attributed to increased sympathetic activities. Presympathetic neurons in the paraventricular nucleus (PVN) of the hypothalamus are capable of modulating sympathetic outflow, thus contributing to the pathogenesis of neurogenic hypertension. Epoxyeicosatrienoic acids (EETs) were reported to have anti-hypertensive effects, which could be degraded by soluble epoxide hydrolase (sEH), encoded by EPHX2. However, the potential effect of EETs on PVN neuron activity and the underlying molecular mechanism are largely unknown. METHODS Knockdown of EPHX2 in spontaneously hypertensive rats (SHRs) was achieved by tail-intravenous injection of AAV plasmid containing shRNA targeting EPHX2. Whole-cell patch clamp was used to record action potentials of PVN neurons. An LC-MS/MS System was employed to determine 14,15-EET levels in rat cerebrospinal fluid. qPCR and western blotting were applied to examine the expression level of EPHX2 in various tissues. ELISA and immunofluorescence staining were applied to examine the levels of ATP, D-serine and glial fibrillary acidic protein (GFAP) in isolated astrocytes. RESULTS The expression level of EPHX2 was higher, while the level of 14,15-EET was lower in SHRs than normotensive Wistar-Kyoto rats (WKY) rats. The spike firing frequency of PNV neurons in SHRs was higher than in WKY rats at a given stimulus current, which could be reduced by either EPHX2 downregulation or 14,15-EET administration. In isolated hypothalamic astrocytes, the elevated intracellular ATP or D-serine induced by Angiotensin II (Ang II) treatment could be rescued by 14,15-EET addition or 14,15-EET combing serine racemase (SR) downregulation by siRNA, respectively. Furthermore, 14,15-EET treatment reduced the Ang II-induced elevation of GFAP immunofluorescence. CONCLUSIONS The elevation of EET levels by EPHX2 downregulation reduced presympathetic neuronal activity in the PVN of SHRs, leading to a reduced sympathetic outflow in hypertension rats. The ATP/SR/D-serine pathway of astrocytes is involved in EET-mediated neuroprotection.
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Affiliation(s)
- Xiaoming Zhu
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
| | - Kuibao Li
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
| | - Yuanfeng Gao
- Heart Center and Beijing Key Laboratory of Hypertension, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
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17
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Royo M, Escolano BA, Madrigal MP, Jurado S. AMPA Receptor Function in Hypothalamic Synapses. Front Synaptic Neurosci 2022; 14:833449. [PMID: 35173598 PMCID: PMC8842481 DOI: 10.3389/fnsyn.2022.833449] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 01/03/2022] [Indexed: 12/15/2022] Open
Abstract
AMPA receptors (AMPARs) are critical for mediating glutamatergic synaptic transmission and plasticity, thus playing a major role in the molecular machinery underlying cellular substrates of memory and learning. Their expression pattern, transport and regulatory mechanisms have been extensively studied in the hippocampus, but their functional properties in other brain regions remain poorly understood. Interestingly, electrophysiological and molecular evidence has confirmed a prominent role of AMPARs in the regulation of hypothalamic function. This review summarizes the existing evidence on AMPAR-mediated transmission in the hypothalamus, where they are believed to orchestrate the role of glutamatergic transmission in autonomous, neuroendocrine function, body homeostasis, and social behavior.
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18
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Saucisse N, Mazier W, Simon V, Binder E, Catania C, Bellocchio L, Romanov RA, Léon S, Matias I, Zizzari P, Quarta C, Cannich A, Meece K, Gonzales D, Clark S, Becker JM, Yeo GSH, Fioramonti X, Merkle FT, Wardlaw SL, Harkany T, Massa F, Marsicano G, Cota D. Functional heterogeneity of POMC neurons relies on mTORC1 signaling. Cell Rep 2021; 37:109800. [PMID: 34644574 DOI: 10.1016/j.celrep.2021.109800] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 07/21/2021] [Accepted: 09/15/2021] [Indexed: 12/14/2022] Open
Abstract
Hypothalamic pro-opiomelanocortin (POMC) neurons are known to trigger satiety. However, these neuronal cells encompass heterogeneous subpopulations that release γ-aminobutyric acid (GABA), glutamate, or both neurotransmitters, whose functions are poorly defined. Using conditional mutagenesis and chemogenetics, we show that blockade of the energy sensor mechanistic target of rapamycin complex 1 (mTORC1) in POMC neurons causes hyperphagia by mimicking a cellular negative energy state. This is associated with decreased POMC-derived anorexigenic α-melanocyte-stimulating hormone and recruitment of POMC/GABAergic neurotransmission, which is restrained by cannabinoid type 1 receptor signaling. Electrophysiology and optogenetic studies further reveal that pharmacological blockade of mTORC1 simultaneously activates POMC/GABAergic neurons and inhibits POMC/glutamatergic ones, implying that the functional specificity of these subpopulations relies on mTORC1 activity. Finally, POMC neurons with different neurotransmitter profiles possess specific molecular signatures and spatial distribution. Altogether, these findings suggest that mTORC1 orchestrates the activity of distinct POMC neurons subpopulations to regulate feeding behavior.
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Affiliation(s)
- Nicolas Saucisse
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Wilfrid Mazier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Vincent Simon
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Elke Binder
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Caterina Catania
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Luigi Bellocchio
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria
| | - Stéphane Léon
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Isabelle Matias
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Philippe Zizzari
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Carmelo Quarta
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Astrid Cannich
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Kana Meece
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Delphine Gonzales
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Samantha Clark
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Julia M Becker
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Giles S H Yeo
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Xavier Fioramonti
- NutriNeuro, UMR 1286 INRAE, Bordeaux University, Bordeaux INP, F-33000 Bordeaux, France
| | - Florian T Merkle
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK; Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge Biomedical Campus, Puddicombe Way, Cambridge CB2 0AW, UK
| | - Sharon L Wardlaw
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria; Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Federico Massa
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Giovanni Marsicano
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France.
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19
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Arcuate and Preoptic Kisspeptin Neurons Exhibit Differential Projections to Hypothalamic Nuclei and Exert Opposite Postsynaptic Effects on Hypothalamic Paraventricular and Dorsomedial Nuclei in the Female Mouse. eNeuro 2021; 8:ENEURO.0093-21.2021. [PMID: 34281980 PMCID: PMC8354717 DOI: 10.1523/eneuro.0093-21.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/21/2021] [Accepted: 07/11/2021] [Indexed: 01/24/2023] Open
Abstract
Kisspeptin (Kiss1) neurons provide indispensable excitatory input to gonadotropin-releasing hormone (GnRH) neurons, which is important for the coordinated release of gonadotropins, estrous cyclicity and ovulation. However, Kiss1 neurons also send projections to many other brain regions within and outside the hypothalamus. Two different populations of Kiss1 neurons, one in the arcuate nucleus (Kiss1ARH) and another in the anteroventral periventricular nucleus (AVPV) and periventricular nucleus (PeN; Kiss1AVPV/PeN) of the hypothalamus are differentially regulated by ovarian steroids, and are believed to form direct contacts with GnRH neurons as well as other neurons. To investigate the projection fields from Kiss1AVPV/PeN and Kiss1ARH neurons in female mice, we used anterograde projection analysis, and channelrhodopsin-assisted circuit mapping (CRACM) to explore their functional input to select target neurons within the paraventricular (PVH) and dorsomedial (DMH) hypothalamus, key preautonomic nuclei. Cre-dependent viral (AAV1-DIO-ChR2 mCherry) vectors were injected into the brain to label the two Kiss1 neuronal populations. Immunocytochemistry (ICC) for mCherry and neuropeptides combined with confocal microscopy was used to determine the projection-fields of both Kiss1 neuronal groups. Whole-cell electrophysiology and optogenetics were used to elucidate the functional input to the PVH and DMH. Our analysis revealed many common but also several clearly separate projection fields between the two different populations of Kiss1 neurons. In addition, optogenetic stimulation of Kiss1 projections to PVH prodynorphin, Vglut2 and DMH CART-expressing neurons, revealed excitatory glutamatergic input from Kiss1ARH neurons and inhibitory GABAergic input from Kiss1AVPV/PeN neurons. Therefore, these steroid-sensitive Kiss1 neuronal groups can differentially control the excitability of target neurons to coordinate autonomic functions with reproduction.
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20
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Sheng W, Harden SW, Tan Y, Krause EG, Frazier CJ. Dendritic osmosensors modulate activity-induced calcium influx in oxytocinergic magnocellular neurons of the mouse PVN. eLife 2021; 10:e63486. [PMID: 34250900 PMCID: PMC8457833 DOI: 10.7554/elife.63486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 07/11/2021] [Indexed: 11/13/2022] Open
Abstract
Hypothalamic oxytocinergic magnocellular neurons have a fascinating ability to release peptide from both their axon terminals and from their dendrites. Existing data indicates that the relationship between somatic activity and dendritic release is not constant, but the mechanisms through which this relationship can be modulated are not completely understood. Here, we use a combination of electrical and optical recording techniques to quantify activity-induced calcium influx in proximal vs. distal dendrites of oxytocinergic magnocellular neurons located in the paraventricular nucleus of the hypothalamus (OT-MCNs). Results reveal that the dendrites of OT-MCNs are weak conductors of somatic voltage changes; however, activity-induced dendritic calcium influx can be robustly regulated by both osmosensitive and non-osmosensitive ion channels located along the dendritic membrane. Overall, this study reveals that dendritic conductivity is a dynamic and endogenously regulated feature of OT-MCNs that is likely to have substantial functional impact on central oxytocin release.
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Affiliation(s)
- Wanhui Sheng
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
| | - Scott W Harden
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
| | - Yalun Tan
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
- Department of Anesthesiology, School of Medicine, Stanford UniversityStanfordUnited States
| | - Eric G Krause
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of FloridaGainesvilleUnited States
- Evelyn F. and William L. McKnight Brain Institute, University of FloridaGainesvilleUnited States
| | - Charles J Frazier
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of FloridaGainesvilleUnited States
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21
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Ferreira-Neto HC, Antunes VR, Stern JE. Purinergic P2 and glutamate NMDA receptor coupling contributes to osmotically driven excitability in hypothalamic magnocellular neurosecretory neurons. J Physiol 2021; 599:3531-3547. [PMID: 34053068 DOI: 10.1113/jp281411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/28/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Purinergic and glutamatergic signalling pathways play a key role in regulating the activity of hypothalamic magnocellular neurosecretory neurons (MNNs). However, the precise cellular mechanisms by which ATP and glutamate act in concert to regulate osmotically driven MNN neuronal excitability remains unknown. Here, we report that ATP acts on purinergic P2 receptors in MNNs to potentiate in a Ca2+ -dependent manner extrasynaptic NMDAR function. The P2-NMDAR coupling is engaged in response to an acute hyperosmotic stimulation, contributing to osmotically driven firing activity in MNNs. These results help us to better understand the precise mechanisms contributing to the osmotic regulation of firing activity and hormone release from MNNs. ABSTRACT The firing activity of hypothalamic magnocellular neurosecretory neurons (MNNs) located in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) is coordinated by the combined, fine-tuned action of intrinsic membrane properties, synaptic and extrasynaptic signalling. Among these, purinergic and glutamatergic signalling pathways have been shown to play a key role regulating the activity of MNNs. However, the precise cellular mechanisms by which ATP and glutamate act in concert to regulate osmotically driven MNN neuronal excitability remains unknown. Whole-cell patch-clamp recordings obtained from MNNs showed that ATP (100 μM) induced an increase in firing rate, an effect that was blocked by either 4-[[4-formyl-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]2-pyridinyl]azo]1,3-benzenedisulfonic acid tetrasodium salt (PPADS) (10 μM) or kynurenic acid (1 mm). While ATP did not affect the frequency or magnitude of glutamatergic excitatory postsynaptic currents (EPSCs), it induced an inward shift in the holding current that was prevented by PPADS or kynurenic acid treatment, suggesting that ATP enhances a tonic extrasynaptic glutamatergic excitatory current. We observed that ATP-potentiated glutamatergic receptor-mediated currents were evoked by focal application of L-glu (1 mm) and NMDA (50 μM), but not AMPA (50 μM). ATP potentiation of NMDA-evoked currents was blocked by PPADS (10 μM) and by chelation of intracellular Ca2+ with BAPTA (10 mm). Finally, we report that a hyperosmotic stimulus (mannitol 1%, +55 mOsm/kgH2 O) potentiated NMDA-evoked currents and increased MNN firing activity, effects that were blocked by PPADS. Taken together, our data support a functional excitatory coupling between P2 and extrasynaptic NMDA receptors in MNNs, which is engaged in response to an acute hyperosmotic stimulus.
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Affiliation(s)
- H C Ferreira-Neto
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - V R Antunes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - J E Stern
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
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22
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Chrobok L, Klich JD, Jeczmien-Lazur JS, Pradel K, Palus-Chramiec K, Sanetra AM, Piggins HD, Lewandowski MH. Daily changes in neuronal activities of the dorsal motor nucleus of the vagus under standard and high-fat diet. J Physiol 2021; 600:733-749. [PMID: 34053067 DOI: 10.1113/jp281596] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/24/2021] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Recently, we found that the dorsal vagal complex displays autonomous circadian timekeeping properties The dorsal motor nucleus of the vagus (DMV) is an executory part of this complex - a source of parasympathetic innervation of the gastrointestinal tract Here, we reveal daily changes in the neuronal activities of the rat DMV, including firing rate, intrinsic excitability and synaptic input - all of these peaking in the late day Additionally, we establish that short term high-fat diet disrupts these daily rhythms, boosting the variability in the firing rate, but blunting the DMV responsiveness to ingestive cues These results help us better understand daily control over parasympathetic outflow and provide evidence on its dependence on the high-fat diet ABSTRACT: The suprachiasmatic nuclei (SCN) of the hypothalamus function as the brain's primary circadian clock, but circadian clock genes are also rhythmically expressed in several extra-SCN brain sites where they can exert local temporal control over physiology and behaviour. Recently, we found that the hindbrain dorsal vagal complex possesses strong daily timekeeping capabilities, with the area postrema and nucleus of the solitary tract exhibiting the most robust clock properties. The possibility that the executory part of this complex - the dorsal motor nucleus of the vagus (DMV) - also exhibits daily changes has not been extensively studied. The DMV is the source of vagal efferent motoneurons that regulate gastric motility and emptying and consequently influence meal size and energy homeostasis. We used a combination of multi-channel electrophysiology and patch clamp recordings to gain insight into effects of time of day and diet on these DMV cells. We found that DMV neurons increase their spontaneous activity, excitability and responsiveness to metabolic neuromodulators at late day and this was paralleled with an enhanced synaptic input to these neurons. A high-fat diet typically damps circadian rhythms, but we found that consumption of a high-fat diet paradoxically amplified daily variation of DMV neuronal activity, while blunting the neurons responsiveness to metabolic neuromodulators. In summary, we show for the first time that DMV neural activity changes with time of day, with this temporal variation modulated by diet. These findings have clear implications for our understanding of the daily control of vagal efferents and parasympathetic outflow.
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Affiliation(s)
- Lukasz Chrobok
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, Krakow, 30-387, Poland
| | - Jasmin D Klich
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, Krakow, 30-387, Poland
| | - Jagoda S Jeczmien-Lazur
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, Krakow, 30-387, Poland
| | - Kamil Pradel
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, Krakow, 30-387, Poland
| | - Katarzyna Palus-Chramiec
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, Krakow, 30-387, Poland
| | - Anna M Sanetra
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, Krakow, 30-387, Poland
| | - Hugh D Piggins
- School of Physiology, Pharmacology, and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Marian H Lewandowski
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, Krakow, 30-387, Poland
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23
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Elsaafien K, Kirchner MK, Mohammed M, Eikenberry SA, West C, Scott KA, de Kloet AD, Stern JE, Krause EG. Identification of Novel Cross-Talk between the Neuroendocrine and Autonomic Stress Axes Controlling Blood Pressure. J Neurosci 2021; 41:4641-4657. [PMID: 33858944 PMCID: PMC8260250 DOI: 10.1523/jneurosci.0251-21.2021] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/01/2021] [Accepted: 04/05/2021] [Indexed: 11/21/2022] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) controls neuroendocrine axes and the autonomic nervous system to mount responses that cope with the energetic burdens of psychological or physiological stress. Neurons in the PVN that express the angiotensin Type 1a receptor (PVNAgtr1a) are implicated in neuroendocrine and autonomic stress responses; however, the mechanism by which these neurons coordinate activation of neuroendocrine axes with sympathetic outflow remains unknown. Here, we use a multidisciplinary approach to investigate intra-PVN signaling mechanisms that couple the activity of neurons synthesizing corticotropin-releasing-hormone (CRH) to blood pressure. We used the Cre-Lox system in male mice with in vivo optogenetics and cardiovascular recordings to demonstrate that excitation of PVNAgtr1a promotes elevated blood pressure that is dependent on the sympathetic nervous system. Next, neuroanatomical experiments found that PVNAgtr1a synthesize CRH, and intriguingly, fibers originating from PVNAgtr1a make appositions onto neighboring neurons that send projections to the rostral ventrolateral medulla and express CRH type 1 receptor (CRHR1) mRNA. We then used an ex vivo preparation that combined optogenetics, patch-clamp electrophysiology, and Ca2+ imaging to discover that excitation of PVNAgtr1a drives the local, intra-PVN release of CRH, which activates rostral ventrolateral medulla-projecting neurons via stimulation of CRHR1(s). Finally, we returned to our in vivo preparation and found that CRH receptor antagonism specifically within the PVN lowered blood pressure basally and during optogenetic activation of PVNAgtr1a Collectively, these results demonstrate that angiotensin II acts on PVNAgtr1a to conjoin hypothalamic-pituitary-adrenal axis activity with sympathetically mediated vasoconstriction in male mice.SIGNIFICANCE STATEMENT The survival of an organism is dependent on meeting the energetic demands imposed by stressors. This critical function is accomplished by the CNS's ability to orchestrate simultaneous activities of neurosecretory and autonomic axes. Here, we unveil a novel signaling mechanism within the paraventricular nucleus of the hypothalamus that links excitation of neurons producing corticotropin-releasing-hormone with excitation of neurons controlling sympathetic nervous system activity and blood pressure. The implication is that chronic stress exposure may promote cardiometabolic disease by dysregulating the interneuronal cross-talk revealed by our experiments.
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Affiliation(s)
- Khalid Elsaafien
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32611
- Center of Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, Florida 32611
| | - Matthew K Kirchner
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30302
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30302
| | - Mazher Mohammed
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32611
| | - Sophia A Eikenberry
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, Florida 32611
| | - Chloe West
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30302
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30302
| | - Karen A Scott
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32611
- Center of Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, Florida 32611
| | - Annette D de Kloet
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, Florida 32611
- Center of Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, Florida 32611
- McKnight Brain Institute, University of Florida, Gainesville, Florida 32611
| | - Javier E Stern
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30302
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30302
| | - Eric G Krause
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32611
- Center of Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, Florida 32611
- McKnight Brain Institute, University of Florida, Gainesville, Florida 32611
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24
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Domingos-Souza G, Martinez D, Sinkler S, Heesch CM, Kline DD. Alpha adrenergic receptor signaling in the hypothalamic paraventricular nucleus is diminished by the chronic intermittent hypoxia model of sleep apnea. Exp Neurol 2021; 335:113517. [PMID: 33132201 PMCID: PMC7750300 DOI: 10.1016/j.expneurol.2020.113517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 10/13/2020] [Accepted: 10/20/2020] [Indexed: 01/08/2023]
Abstract
Chronic intermittent hypoxia (CIH) is a model for obstructive sleep apnea. The paraventricular nucleus (PVN) of the hypothalamus has been suggested to contribute to CIH-induced exaggerated cardiorespiratory reflexes, sympathoexcitation and hypertension. This may occur, in part, via activation of the dense catecholaminergic projections to the PVN that originate in the brainstem. However, the contribution of norepinephrine (NE) and activation of its alpha-adrenergic receptors (α-ARs) in the PVN after CIH exposure is unknown. We hypothesized CIH would increase the contribution of catecholaminergic input. To test this notion, we determined the expression of α-AR subtypes, catecholamine terminal density, and synaptic properties of PVN parvocellular neurons in response to α-AR activation in male Sprague-Dawley normoxic (Norm) and CIH exposed rats. CIH decreased mRNA for α1d and α2b AR. Dopamine-β-hydroxylase (DβH) terminals in the PVN were similar between groups. NE and the α1-AR agonist phenylephrine (PE) increased sEPSC frequency after Norm but not CIH. Block of α1-ARs with prazosin alone did not alter sEPSCs after either Norm or CIH but did prevent agonist augmentation of sEPSC frequency following normoxia. These responses to NE were mimicked by PE during action potential block suggesting presynaptic terminal alterations in CIH. Altogether, these results demonstrate that α1-AR activation participates in neuronal responses in Norm, but are attenuated after CIH. These results may provide insight into the cardiovascular, respiratory and autonomic nervous systems alterations in obstructive sleep apnea.
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Affiliation(s)
- Gean Domingos-Souza
- Dept. of Biomedical Sciences and Dalton Cardiovascular Research Center, Univ. of Missouri, Columbia, MO 65211, United States of America
| | - Diana Martinez
- Dept. of Biomedical Sciences and Dalton Cardiovascular Research Center, Univ. of Missouri, Columbia, MO 65211, United States of America
| | - Steven Sinkler
- Dept. of Biomedical Sciences and Dalton Cardiovascular Research Center, Univ. of Missouri, Columbia, MO 65211, United States of America
| | - Cheryl M Heesch
- Dept. of Biomedical Sciences and Dalton Cardiovascular Research Center, Univ. of Missouri, Columbia, MO 65211, United States of America
| | - David D Kline
- Dept. of Biomedical Sciences and Dalton Cardiovascular Research Center, Univ. of Missouri, Columbia, MO 65211, United States of America.
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25
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An Angiotensin-Responsive Connection from the Lamina Terminalis to the Paraventricular Nucleus of the Hypothalamus Evokes Vasopressin Secretion to Increase Blood Pressure in Mice. J Neurosci 2020; 41:1429-1442. [PMID: 33328294 DOI: 10.1523/jneurosci.1600-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 11/29/2020] [Accepted: 12/03/2020] [Indexed: 12/22/2022] Open
Abstract
Blood pressure is controlled by endocrine, autonomic, and behavioral responses that maintain blood volume and perfusion pressure at levels optimal for survival. Although it is clear that central angiotensin type 1a receptors (AT1aR; encoded by the Agtr1a gene) influence these processes, the neuronal circuits mediating these effects are incompletely understood. The present studies characterize the structure and function of AT1aR neurons in the lamina terminalis (containing the median preoptic nucleus and organum vasculosum of the lamina terminalis), thereby evaluating their roles in blood pressure control. Using male Agtr1a-Cre mice, neuroanatomical studies reveal that AT1aR neurons in the area are largely glutamatergic and send projections to the paraventricular nucleus of the hypothalamus (PVN) that appear to synapse onto vasopressin-synthesizing neurons. To evaluate the functionality of these lamina terminalis AT1aR neurons, we virally delivered light-sensitive opsins and then optogenetically excited or inhibited the neurons while evaluating cardiovascular parameters or fluid intake. Optogenetic excitation robustly elevated blood pressure, water intake, and sodium intake, while optogenetic inhibition produced the opposite effects. Intriguingly, optogenetic excitation of these AT1aR neurons of the lamina terminalis also resulted in Fos induction in vasopressin neurons within the PVN and supraoptic nucleus. Further, within the PVN, selective optogenetic stimulation of afferents that arise from these lamina terminalis AT1aR neurons induced glutamate release onto magnocellular neurons and was sufficient to increase blood pressure. These cardiovascular effects were attenuated by systemic pretreatment with a vasopressin-1a-receptor antagonist. Collectively, these data indicate that excitation of lamina terminalis AT1aR neurons induces neuroendocrine and behavioral responses that increase blood pressure.SIGNIFICANCE STATEMENT Hypertension is a widespread health problem and risk factor for cardiovascular disease. Although treatments exist, a substantial percentage of patients suffer from "drug-resistant" hypertension, a condition associated with increased activation of brain angiotensin receptors, enhanced sympathetic nervous system activity, and elevated vasopressin levels. The present study highlights a role for angiotensin Type 1a receptor expressing neurons located within the lamina terminalis in regulating endocrine and behavioral responses that are involved in maintaining cardiovascular homeostasis. More specifically, data presented here reveal functional excitatory connections between angiotensin-sensitive neurons in the lamina terminals and vasopressin neurons in the paraventricular nucleus of the hypothalamus, and further indicate that activation of this circuit raises blood pressure. These neurons may be a promising target for antihypertensive therapeutics.
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26
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Lewis EM, Stein-O'Brien GL, Patino AV, Nardou R, Grossman CD, Brown M, Bangamwabo B, Ndiaye N, Giovinazzo D, Dardani I, Jiang C, Goff LA, Dölen G. Parallel Social Information Processing Circuits Are Differentially Impacted in Autism. Neuron 2020; 108:659-675.e6. [PMID: 33113347 PMCID: PMC8033501 DOI: 10.1016/j.neuron.2020.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/21/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023]
Abstract
Parallel processing circuits are thought to dramatically expand the network capabilities of the nervous system. Magnocellular and parvocellular oxytocin neurons have been proposed to subserve two parallel streams of social information processing, which allow a single molecule to encode a diverse array of ethologically distinct behaviors. Here we provide the first comprehensive characterization of magnocellular and parvocellular oxytocin neurons in male mice, validated across anatomical, projection target, electrophysiological, and transcriptional criteria. We next use novel multiple feature selection tools in Fmr1-KO mice to provide direct evidence that normal functioning of the parvocellular but not magnocellular oxytocin pathway is required for autism-relevant social reward behavior. Finally, we demonstrate that autism risk genes are enriched in parvocellular compared with magnocellular oxytocin neurons. Taken together, these results provide the first evidence that oxytocin-pathway-specific pathogenic mechanisms account for social impairments across a broad range of autism etiologies.
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Affiliation(s)
- Eastman M Lewis
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Genevieve L Stein-O'Brien
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Division of Biostatistics and Bioinformatics, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, School of Medicine, Baltimore, MD 21205; McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Alejandra V Patino
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Romain Nardou
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Cooper D Grossman
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Matthew Brown
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Bidii Bangamwabo
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Ndeye Ndiaye
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Daniel Giovinazzo
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Ian Dardani
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Connie Jiang
- Cell and Molecular Biology Group, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Loyal A Goff
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
| | - Gül Dölen
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Brain Science Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Kavli Neuroscience Discovery Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; The Wendy Klag Institute for Autism and Developmental Disabilities, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
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Phumsatitpong C, De Guzman RM, Zuloaga DG, Moenter SM. A CRH Receptor Type 1 Agonist Increases GABA Transmission to GnRH Neurons in a Circulating-Estradiol-Dependent Manner. Endocrinology 2020; 161:5892962. [PMID: 32798220 PMCID: PMC7547842 DOI: 10.1210/endocr/bqaa140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/06/2020] [Indexed: 12/15/2022]
Abstract
GnRH neurons are central regulators of reproduction and respond to factors affecting fertility, such as stress. Corticotropin-releasing hormone (CRH) is released during stress response. In brain slices from unstressed controls, CRH has opposite, estradiol-dependent effects on GnRH neuron firing depending on the CRH receptor activated; activating CRHR-1 stimulates whereas activating CRHR-2 suppresses activity. We investigated possible direct and indirect mechanisms. Mice were ovariectomized and either not treated further (OVX) or given a capsule producing high positive feedback (OVX + E) or low negative feedback (OVX + low E) physiologic circulating estradiol levels. We tested possible direct effects on GnRH neurons by altering voltage-gated potassium currents. Two types of voltage-gated potassium currents (transient IA and sustained IK) were measured; neither CRHR-1 nor CRHR-2 agonists altered potassium current density in GnRH neurons from OVX + E mice. Further, neither CRH nor receptor-specific agonists altered action potential generation in response to current injection in GnRH neurons from OVX + E mice. To test the possible indirect actions, GABAergic postsynaptic currents were monitored. A CRHR-1 agonist increased GABAergic transmission frequency to GnRH neurons from OVX + E, but not OVX, mice, whereas a CRHR-2 agonist had no effect. Finally, we tested if CRH alters the firing rate of arcuate kisspeptin neurons, which provide an important excitatory neuromodulatory input to GnRH neurons. CRH did not acutely alter firing activity of these neurons from OVX, OVX + E or OVX + low E mice. These results suggest CRH increases GnRH neuron activity in an estradiol-dependent manner in part by activating GABAergic afferents. Mechanisms underlying inhibitory effects of CRH remain unknown.
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Affiliation(s)
| | | | | | - Suzanne M Moenter
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, US
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, US
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, US
- Correspondence: Suzanne M. Moenter; 7725 Med Sci II; 1137 E Catherine St; Ann Arbor, MI 48109-5622. E-mail:
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Social touch promotes interfemale communication via activation of parvocellular oxytocin neurons. Nat Neurosci 2020; 23:1125-1137. [PMID: 32719563 DOI: 10.1038/s41593-020-0674-y] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/18/2020] [Indexed: 12/19/2022]
Abstract
Oxytocin (OT) is a great facilitator of social life but, although its effects on socially relevant brain regions have been extensively studied, OT neuron activity during actual social interactions remains unexplored. Most OT neurons are magnocellular neurons, which simultaneously project to the pituitary and forebrain regions involved in social behaviors. In the present study, we show that a much smaller population of OT neurons, parvocellular neurons that do not project to the pituitary but synapse onto magnocellular neurons, is preferentially activated by somatosensory stimuli. This activation is transmitted to the larger population of magnocellular neurons, which consequently show coordinated increases in their activity during social interactions between virgin female rats. Selectively activating these parvocellular neurons promotes social motivation, whereas inhibiting them reduces social interactions. Thus, parvocellular OT neurons receive particular inputs to control social behavior by coordinating the responses of the much larger population of magnocellular OT neurons.
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29
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Kania A, Szlaga A, Sambak P, Gugula A, Blasiak E, Micioni Di Bonaventura MV, Hossain MA, Cifani C, Hess G, Gundlach AL, Blasiak A. RLN3/RXFP3 Signaling in the PVN Inhibits Magnocellular Neurons via M-like Current Activation and Contributes to Binge Eating Behavior. J Neurosci 2020; 40:5362-5375. [PMID: 32532885 PMCID: PMC7343322 DOI: 10.1523/jneurosci.2895-19.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/17/2020] [Accepted: 05/21/2020] [Indexed: 12/20/2022] Open
Abstract
Binge-eating disorder is the most common eating disorder. Various neuropeptides play important roles in the regulation of feeding behavior, including relaxin-3 (RLN3), which stimulates food intake in rats through the activation of the relaxin-family peptide-3 receptor (RXFP3). Here we demonstrate that a likely mechanism underlying the orexigenic action of RLN3 is RXFP3-mediated inhibition of oxytocin- and arginine-vasopressin-synthesizing paraventricular nucleus (PVN) magnocellular neurosecretory cells. Moreover, we reveal that, in male and female rats, this action depends on M-like potassium conductance. Notably, higher intra- and peri-PVN RLN3 fiber densities were observed in females, which may constitute an anatomic substrate for observed sex differences in binge-eating disorder. Finally, in a model of binge-eating in female rats, RXFP3 blockade within the PVN prevented binge-eating behavior. These data demonstrate a direct RLN3/RXFP3 action in the PVN of male and female rats, identify the associated ionic mechanisms, and reveal that hypothalamic RLN3/RXFP3 signaling regulates binge-eating behavior.SIGNIFICANCE STATEMENT Binge-eating disorder is the most common eating disorder worldwide, affecting women twice as frequently as men. Various neuropeptides play important roles in the regulation of feeding behavior, including relaxin-3, which acts via the relaxin-family peptide-3 receptor (RXFP3). Using a model of binge-eating, we demonstrated that relaxin-3/RXFP3 signaling in the hypothalamic paraventricular nucleus (PVN) is necessary for the expression of binge-eating behavior in female rats. Moreover, we elucidated the neuronal mechanism of RLN3/RXFP3 signaling in PVN in male and female rats and characterized sex differences in the RLN3 innervation of the PVN. These findings increase our understanding of the brain circuits and neurotransmitters involved in binge-eating disorder pathology and identify RXFP3 as a therapeutic target for binge-like eating disorders.
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Affiliation(s)
- Alan Kania
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, 62032, Italy
| | - Agata Szlaga
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
| | - Patryk Sambak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
| | - Ewa Blasiak
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, 30-387, Poland
| | | | - Mohammad Akhter Hossain
- Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, 3010 Victoria, Australia
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, 62032, Italy
| | - Grzegorz Hess
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
| | - Andrew L Gundlach
- Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, 3010 Victoria, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
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30
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Dai YWE, Lee YH, Li TL, Hwang LL. Mechanisms of orexin 2 receptor-mediated depolarization in the rat paraventricular nucleus of the hypothalamus. Eur J Pharmacol 2020; 869:172802. [DOI: 10.1016/j.ejphar.2019.172802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 11/12/2019] [Accepted: 11/14/2019] [Indexed: 12/18/2022]
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31
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Kania A, Sambak P, Gugula A, Szlaga A, Soltys Z, Blasiak T, Hess G, Rajfur Z, Blasiak A. Electrophysiology and distribution of oxytocin and vasopressin neurons in the hypothalamic paraventricular nucleus: a study in male and female rats. Brain Struct Funct 2019; 225:285-304. [DOI: 10.1007/s00429-019-01989-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 11/15/2019] [Indexed: 12/30/2022]
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32
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Milanick WJ, Polo-Parada L, Dantzler HA, Kline DD. Activation of alpha-1 adrenergic receptors increases cytosolic calcium in neurones of the paraventricular nucleus of the hypothalamus. J Neuroendocrinol 2019; 31:e12791. [PMID: 31494990 PMCID: PMC7003713 DOI: 10.1111/jne.12791] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 08/22/2019] [Accepted: 09/04/2019] [Indexed: 12/15/2022]
Abstract
Norepinephrine (NE) activates adrenergic receptors (ARs) in the hypothalamic paraventricular nucleus (PVN) to increase excitatory currents, depolarise neurones and, ultimately, augment neuro-sympathetic and endocrine output. Such cellular events are known to potentiate intracellular calcium ([Ca2+ ]i ); however, the role of NE with respect to modulating [Ca2+ ]i in PVN neurones and the mechanisms by which this may occur remain unclear. We evaluated the effects of NE on [Ca2+ ]i of acutely isolated PVN neurones using Fura-2 imaging. NE induced a slow increase in [Ca2+ ]i compared to artificial cerebrospinal fluid vehicle. NE-induced Ca2+ elevations were mimicked by the α1 -AR agonist phenylephrine (PE) but not by α2 -AR agonist clonidine (CLON). NE and PE but not CLON also increased the overall number of neurones that increase [Ca2+ ]i (ie, responders). Elimination of extracellular Ca2+ or intracellular endoplasmic reticulum Ca2+ stores abolished the increase in [Ca2+ ]i and reduced responders. Blockade of voltage-dependent Ca2+ channels abolished the α1 -AR induced increase in [Ca2+ ]i and number of responders, as did inhibition of phospholipase C inhibitor, protein kinase C and inositol triphosphate receptors. Spontaneous phasic Ca2+ events, however, were not altered by NE, PE or CLON. Repeated K+ -induced membrane depolarisation produced repetitive [Ca2+ ]i elevations. NE and PE increased baseline Ca2+ , whereas NE decreased the peak amplitude. CLON also decreased peak amplitude but did not affect baseline [Ca2+ ]i . Taken together, these data suggest receptor-specific influence of α1 and α2 receptors on the various modes of calcium entry in PVN neurones. They further suggest Ca2+ increase via α1 -ARs is co-dependent on extracellular Ca2+ influx and intracellular Ca2+ release, possibly via a phospholipase C inhibitor-mediated signalling cascade.
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Affiliation(s)
- William J. Milanick
- Department of Biomedical Sciences, University of Missouri, Columbia MO 65211
- Dalton Cardiovascular Research Center, University of Missouri, Columbia MO 65211
| | - Luis Polo-Parada
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia MO 65211
- Dalton Cardiovascular Research Center, University of Missouri, Columbia MO 65211
| | - Heather A. Dantzler
- Department of Biomedical Sciences, University of Missouri, Columbia MO 65211
- Dalton Cardiovascular Research Center, University of Missouri, Columbia MO 65211
| | - David D. Kline
- Department of Biomedical Sciences, University of Missouri, Columbia MO 65211
- Dalton Cardiovascular Research Center, University of Missouri, Columbia MO 65211
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Mukerjee S, Gao H, Xu J, Sato R, Zsombok A, Lazartigues E. ACE2 and ADAM17 Interaction Regulates the Activity of Presympathetic Neurons. Hypertension 2019; 74:1181-1191. [PMID: 31564162 DOI: 10.1161/hypertensionaha.119.13133] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Brain renin angiotensin system within the paraventricular nucleus plays a critical role in balancing excitatory and inhibitory inputs to modulate sympathetic output and blood pressure regulation. We previously identified ACE2 and ADAM17 as a compensatory enzyme and a sheddase, respectively, involved in brain renin angiotensin system regulation. Here, we investigated the opposing contribution of ACE2 and ADAM17 to hypothalamic presympathetic activity and ultimately neurogenic hypertension. New mouse models were generated where ACE2 and ADAM17 were selectively knocked down from all neurons (AC-N) or Sim1 neurons (SAT), respectively. Neuronal ACE2 deletion revealed a reduction of inhibitory inputs to AC-N presympathetic neurons relevant to blood pressure regulation. Primary neuron cultures confirmed ACE2 expression on GABAergic neurons synapsing onto excitatory neurons within the hypothalamus but not on glutamatergic neurons. ADAM17 expression was shown to colocalize with angiotensin-II type 1 receptors on Sim1 neurons, and the pressor relevance of this neuronal population was demonstrated by photoactivation. Selective knockdown of ADAM17 was associated with a reduction of FosB gene expression, increased vagal tone, and prevented the acute pressor response to centrally administered angiotensin-II. Chronically, SAT mice exhibited a blunted blood pressure elevation and preserved ACE2 activity during development of salt-sensitive hypertension. Bicuculline injection in those models confirmed the supporting role of ACE2 on GABAergic tone to the paraventricular nucleus. Together, our study demonstrates the contrasting impact of ACE2 and ADAM17 on neuronal excitability of presympathetic neurons within the paraventricular nucleus and the consequences of this mutual regulation in the context of neurogenic hypertension.
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Affiliation(s)
- Snigdha Mukerjee
- From the Department of Pharmacology and Experimental Therapeutics (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans
| | - Hong Gao
- Department of Physiology, School of Medicine (H.G., R.S., A.Z.), Tulane University, New Orleans.,Brain Institute (H.G., A.Z.), Tulane University, New Orleans
| | - Jiaxi Xu
- From the Department of Pharmacology and Experimental Therapeutics (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,SouthEast Louisiana Veterans Health Care System, New Orleans (J.X., E.L.)
| | - Ryosuke Sato
- Department of Physiology, School of Medicine (H.G., R.S., A.Z.), Tulane University, New Orleans
| | - Andrea Zsombok
- Department of Physiology, School of Medicine (H.G., R.S., A.Z.), Tulane University, New Orleans.,Brain Institute (H.G., A.Z.), Tulane University, New Orleans
| | - Eric Lazartigues
- From the Department of Pharmacology and Experimental Therapeutics (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,SouthEast Louisiana Veterans Health Care System, New Orleans (J.X., E.L.)
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Jiang Z, Rajamanickam S, Justice NJ. CRF signaling between neurons in the paraventricular nucleus of the hypothalamus (PVN) coordinates stress responses. Neurobiol Stress 2019; 11:100192. [PMID: 31516918 PMCID: PMC6732729 DOI: 10.1016/j.ynstr.2019.100192] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 12/22/2022] Open
Abstract
The importance of a precisely coordinated neuroendocrine, autonomic, and behavioral stress response was a primary theme at the Stress Neurobiology Workshop 2018, held in the beautiful setting of Banff Provincial Park in Alberta, Canada. Much of the research featured at this meeting reinforced the importance of appropriately responding to stress in order to avoid various neuropsychiatric pathologies, including Post-Traumatic Stress Disorder (PTSD), depression, and addiction. Corticotropin-Releasing Factor (CRF) neurons in the paraventricular nucleus of the hypothalamus (PVN) are central players in the stress response, integrating both external and visceral stress-relevant information, then directing neuroendocrine, autonomic and behavioral adaptations via endocrine and neural outputs of the PVN. The PVN contains a densely packed array of neuron types that respond to stress, including CRF neurons that activate the Hypothalamic-Pituitary-Adrenal (HPA) axis. Recently, identification of a new population of neurons in the PVN that express CRF Receptor 1 (CRFR1) has suggested that CRF release in the PVN signals to neighboring CRF responsive neurons, potentially functioning in HPA axis feedback, neuroendocrine coordination, and autonomic signaling. Here, we review our recent work characterizing an intra-PVN microcircuit in which locally released CRF release activates CRFR1+ neurons that make recurrent inhibitory GABAergic synapses onto CRF neurons to dampen excitability , therebylimiting HPA axis hyperactivity in response to stress and promoting stress recovery, which we presented in a poster session at the conference. We then discuss questions that have arisen following publication of our initial characterization of the microcircuit, regarding specific features of intra-PVN CRF signaling and its potential role in coordinating neuroendocrine, autonomic, and behavioral outputs of the PVN. Our presented work, as well as many of the presentations at the Stress Neurobiology Workshop 2018 together establish intra-PVN signaling as an important regulatory node in stress response pathways, which are central to the pathogenesis of neuropsychiatric disorders.
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Affiliation(s)
- Zhiying Jiang
- The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, McGovern Medical School, The University of Texas Health Science Center at Houston, Texas, 77030, USA
| | - Shivakumar Rajamanickam
- The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, McGovern Medical School, The University of Texas Health Science Center at Houston, Texas, 77030, USA
| | - Nicholas J Justice
- The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, McGovern Medical School, The University of Texas Health Science Center at Houston, Texas, 77030, USA
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mTORC1 and CB1 receptor signaling regulate excitatory glutamatergic inputs onto the hypothalamic paraventricular nucleus in response to energy availability. Mol Metab 2019; 28:151-159. [PMID: 31420305 PMCID: PMC6822143 DOI: 10.1016/j.molmet.2019.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/31/2019] [Accepted: 08/02/2019] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE The hypothalamic paraventricular nucleus (PVN) is a key target of the melanocortin system, which orchestrates behavioral and metabolic responses depending on energy availability. The mechanistic target of rapamycin complex 1 (mTORC1) and the endocannabinoid type 1 receptor (CB1R) pathways are two key signaling systems involved in the regulation of energy balance whose activity closely depends upon energy availability. Here we tested the hypothesis that modulation of mTORC1 and CB1R signaling regulates excitatory glutamatergic inputs onto the PVN. METHODS Patch-clamp recordings in C57BL/6J mice, in mice lacking the mTORC1 component Rptor or CB1R in pro-opio-melanocortin (POMC) neurons, combined with pharmacology targeting mTORC1, the melanocortin receptor type 4 (MC4R), or the endocannabinoid system under chow or a hypercaloric diet. RESULTS Acute pharmacological inhibition of mTORC1 in C57BL/6J mice decreased glutamatergic inputs onto the PVN via a mechanism requiring modulation of MC4R, endocannabinoid 2-AG mobilization by PVN parvocellular neurons, and retrograde activation of presynaptic CB1R. Further electrophysiology studies using mice lacking mTORC1 activity or CB1R in POMC neurons indicated that the observed effects involved mTORC1 and CB1R-dependent regulation of glutamate release from POMC neurons. Finally, energy surfeit caused by hypercaloric high-fat diet feeding, rapidly and time-dependently altered the glutamatergic inputs onto parvocellular neurons and the ability of mTORC1 and CB1R signaling to modulate such excitatory activity. CONCLUSIONS These findings pinpoint the relationship between mTORC1 and endocannabinoid-CB1R signaling in the regulation of the POMC-mediated glutamatergic inputs onto PVN parvocellular neurons and its rapid alteration in conditions favoring the development of obesity.
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Pitra S, Worker CJ, Feng Y, Stern JE. Exacerbated effects of prorenin on hypothalamic magnocellular neuronal activity and vasopressin plasma levels during salt-sensitive hypertension. Am J Physiol Heart Circ Physiol 2019; 317:H496-H504. [PMID: 31274353 DOI: 10.1152/ajpheart.00063.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Accumulating evidence supports that the brain renin-angiotensin system (RAS), including prorenin (PR) and its receptor (PRR), two newly discovered RAS players, contribute to sympathoexcitation in salt-sensitive hypertension. Still, whether PR also contributed to elevated circulating levels of neurohormones such as vasopressin (VP) during salt-sensitive hypertension, and if so, what are the precise underlying mechanisms, remains to be determined. To address these questions, we obtained patch-clamp recordings from hypothalamic magnocellular neurosecretory neurons (MNNs) that synthesize the neurohormones oxytocin and VP in acute hypothalamic slices obtained from sham and deoxycorticosterone acetate (DOCA)-salt-treated hypertensive rats. We found that focal application of PR markedly increased membrane excitability and firing responses in MNNs of DOCA-salt, compared with sham rats. This effect included a shorter latency to spike initiation and increased numbers of spikes in response to depolarizing stimuli and was mediated by a more robust inhibition of A-type K+ channels in DOCA-salt compared with sham rats. On the other hand, the afterhyperpolarizing potential mediated by the activation of Ca2+-dependent K+ channel was not affected by PR. mRNA expression of PRR, VP, and the Kv4.3 K+ channel subunit in the supraoptic nucleus of DOCA-salt hypertensive rats was increased compared with sham rats. Finally, we report a significant decrease of plasma VP levels in neuron-selective PRR knockdown mice treated with DOCA-salt, compared with wild-type DOCA-salt-treated mice. Together, these results support that activation of PRR contributes to increased excitability and firing discharge of MNNs and increased plasma levels of VP in DOCA-salt hypertension.NEW & NOTEWORTHY Our studies support that prorenin (PR) and its receptor (PRR) within the hypothalamus contribute to elevated plasma vasopressin levels in deoxycorticosterone acetate-salt hypertension, in part because of an exacerbated effect of PR on magnocellular neurosecretory neuron excitability; Moreover, our study implicates A-type K+ channels as key underlying molecular targets mediating these effects. Thus, PR/PRR stands as a novel therapeutic target for the treatment of neurohumoral activation in salt-sensitive hypertension.
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Affiliation(s)
- Soledad Pitra
- Department of Physiology, Medical College of Georgia, Augusta University, Georgia
| | - Caleb J Worker
- Department of Pharmacology, Physiology, and Cell Biology, University of Nevada, Reno, Nevada
| | - Yumei Feng
- Department of Pharmacology, Physiology, and Cell Biology, University of Nevada, Reno, Nevada
| | - Javier E Stern
- Department of Physiology, Medical College of Georgia, Augusta University, Georgia
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Dantzler HA, Matott MP, Martinez D, Kline DD. Hydrogen peroxide inhibits neurons in the paraventricular nucleus of the hypothalamus via potassium channel activation. Am J Physiol Regul Integr Comp Physiol 2019; 317:R121-R133. [PMID: 31042419 DOI: 10.1152/ajpregu.00054.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The paraventricular nucleus (PVN) of the hypothalamus is an important homeostatic and reflex center for neuroendocrine, respiratory, and autonomic regulation, including during hypoxic stressor challenges. Such challenges increase reactive oxygen species (ROS) to modulate synaptic, neuronal, and ion channel activity. Previously, in the nucleus tractus solitarius, another cardiorespiratory nucleus, we showed that the ROS H2O2 induced membrane hyperpolarization and reduced action potential discharge via increased K+ conductance at the resting potential. Here, we sought to determine the homogeneity of influence and mechanism of action of H2O2 on PVN neurons. We recorded PVN neurons in isolation and in an acute slice preparation, which leaves neurons in their semi-intact network. Regardless of preparation, H2O2 hyperpolarized PVN neurons and decreased action potential discharge. In the slice preparation, H2O2 also decreased spontaneous excitatory postsynaptic current frequency, but not amplitude. To examine potential mechanisms, we investigated the influence of the K+ channel blockers Ba2+, Cs+, and glibenclamide on membrane potential, as well as the ionic currents active at resting potential and outward K+ currents (IK) upon depolarization. The H2O2 hyperpolarization was blocked by K+ channel blockers. H2O2 did not alter currents between -50 and -110 mV. However, H2O2 induced an outward IK at -50 mV yet, at potentials more positive to 0 mV H2O2, decreased IK. Elevated intracellular antioxidant catalase eliminated H2O2 effects. These data indicate that H2O2 alters synaptic and neuronal properties of PVN neurons likely via membrane hyperpolarization and alteration of IK, which may ultimately alter cardiorespiratory reflexes.
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Affiliation(s)
- Heather A Dantzler
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri
| | - Michael P Matott
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri
| | - Diana Martinez
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri
| | - David D Kline
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri
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Synaptic adaptations in the central amygdala and hypothalamic paraventricular nucleus associated with protracted ethanol abstinence in male rhesus monkeys. Neuropsychopharmacology 2019; 44:982-993. [PMID: 30555160 PMCID: PMC6461779 DOI: 10.1038/s41386-018-0290-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 11/25/2018] [Accepted: 11/27/2018] [Indexed: 01/06/2023]
Abstract
Alcohol use disorder is a significant global burden. Stress has been identified as an etiological factor in the initiation and continuation of ethanol consumption. Understanding adaptations within stress circuitry is an important step toward novel treatment strategies. The effects of protracted abstinence following long-term ethanol self-administration on the central nucleus of the amygdala (CeA) and the hypothalamic paraventricular nucleus (PVN) were evaluated in male rhesus monkeys. Using whole-cell patch-clamp electrophysiology, inhibitory GABAergic transmission in the CeA and excitatory glutamatergic transmission in the PVN were measured. CeA neurons from abstinent drinkers displayed an elevated baseline spontaneous inhibitory postsynaptic current (sIPSC) frequency compared with controls, indicating increased presynaptic GABA release. Application of acute ethanol significantly increased the frequency of sIPSCs in controls, but not in abstinent drinkers, suggesting a tolerance to ethanol-enhanced GABA release in abstinent rhesus monkeys with a history of chronic ethanol self-administration and repeated abstinence. In the PVN, the frequency of spontaneous excitatory postsynaptic currents (sEPSC) was elevated in abstinent drinkers compared with controls, indicating increased presynaptic glutamate release. Notably, acute ethanol decreased presynaptic glutamate release onto parvocellular PVN neurons in both controls and abstinent drinkers, suggesting a lack of tolerance to acute ethanol among PVN neurons. These results are the first to demonstrate distinct synaptic adaptations and ethanol sensitivity in both the extrahypothalamic and hypothalamic stress circuits in abstinent rhesus males. Importantly, our findings describe adaptations in stress circuitry present in the brain at a state during abstinence, just prior to relapse to ethanol drinking.
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Harris C, Weiss GL, Di S, Tasker JG. Cell signaling dependence of rapid glucocorticoid-induced endocannabinoid synthesis in hypothalamic neuroendocrine cells. Neurobiol Stress 2019; 10:100158. [PMID: 31193551 PMCID: PMC6535624 DOI: 10.1016/j.ynstr.2019.100158] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/01/2019] [Accepted: 03/18/2019] [Indexed: 12/30/2022] Open
Abstract
Glucocorticoids induce a rapid synthesis of endocannabinoid in hypothalamic neuroendocrine cells by activation of a putative membrane receptor. Somato-dendritically released endocannabinoid acts as a retrograde messenger to suppress excitatory synaptic inputs to corticotropin-releasing hormone-, oxytocin-, and vasopressin-secreting cells. The non-genomic signaling mechanism responsible for rapid endocannabinoid synthesis by glucocorticoids has yet to be fully characterized. Here we manipulated cell signaling molecules pharmacologically using an intracellular approach to elucidate the signaling pathway activated by the membrane glucocorticoid receptor in hypothalamic neuroendocrine cells. We found that rapid glucocorticoid-induced endocannabinoid synthesis in magnocellular neuroendocrine cells requires the sequential activation of multiple kinases, phospholipase C, and intracellular calcium mobilization. While there remain gaps in our understanding, our findings reveal many of the critical players in the rapid glucocorticoid signaling that culminates in the retrograde endocannabinoid modulation of excitatory synaptic transmission.
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Affiliation(s)
- Christina Harris
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
| | - Grant L Weiss
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
| | - Shi Di
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
| | - Jeffrey G Tasker
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA.,Tulane Brain Institute, Tulane University, New Orleans, LA, USA
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Armstrong WE, Foehring RC, Kirchner MK, Sladek CD. Electrophysiological properties of identified oxytocin and vasopressin neurones. J Neuroendocrinol 2019; 31:e12666. [PMID: 30521104 PMCID: PMC7251933 DOI: 10.1111/jne.12666] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/26/2018] [Accepted: 11/29/2018] [Indexed: 12/18/2022]
Abstract
To understand the contribution of intrinsic membrane properties to the different in vivo firing patterns of oxytocin (OT) and vasopressin (VP) neurones, in vitro studies are needed, where stable intracellular recordings can be made. Combining immunochemistry for OT and VP and intracellular dye injections allows characterisation of identified OT and VP neurones, and several differences between the two cell types have emerged. These include a greater transient K+ current that delays spiking to stimulus onset, and a higher Na+ current density leading to greater spike amplitude and a more stable spike threshold, in VP neurones. VP neurones also show a greater incidence of both fast and slow Ca2+ -dependent depolarising afterpotentials, the latter of which summate to plateau potentials and contribute to phasic bursting. By contrast, OT neurones exhibit a sustained outwardly rectifying potential (SOR), as well as a consequent depolarising rebound potential, not found in VP neurones. The SOR makes OT neurones more susceptible to spontaneous inhibitory synaptic inputs and correlates with a longer period of spike frequency adaptation in these neurones. Although both types exhibit prominent Ca2+ -dependent afterhyperpolarising potentials (AHPs) that limit firing rate and contribute to bursting patterns, Ca2+ -dependent AHPs in OT neurones selectively show significant increases during pregnancy and lactation. In OT neurones, but not VP neurones, AHPs are highly dependent on the constitutive presence of the second messenger, phosphatidylinositol 4,5-bisphosphate, which permissively gates N-type channels that contribute the Ca2+ during spike trains that activates the AHP. By contrast to the intrinsic properties supporting phasic bursting in VP neurones, the synchronous bursting of OT neurones has only been demonstrated in vitro in cultured hypothalamic explants and is completely dependent on synaptic transmission. Additional differences in Ca2+ channel expression between the two neurosecretory terminal types suggests these channels are also critical players in the differential release of OT and VP during repetitive spiking, in addition to their importance to the potentials controlling firing patterns.
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Affiliation(s)
- William E Armstrong
- Department of Anatomy & Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Robert C Foehring
- Department of Anatomy & Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Matthew K Kirchner
- Department of Anatomy & Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Celia D Sladek
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado
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Pitra S, Zhang M, Cauley E, Stern JE. NMDA receptors potentiate activity-dependent dendritic release of neuropeptides from hypothalamic neurons. J Physiol 2019; 597:1735-1756. [PMID: 30629746 DOI: 10.1113/jp277167] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 01/02/2019] [Indexed: 01/30/2023] Open
Abstract
KEY POINTS Using 'sniffer' cell biosensors, we evaluated the effects of specific firing patterns and frequencies on activity-dependent somatodendritic release of vasopressin from paraventricular nucleus neurones. Somatodendritic release of vasopressin was rarely observed during continuous firing but was strengthened by clustered activity. Moreover, release evoked at any given frequency was robustly potentiated by NMDA receptor (NMDAR)-mediated firing. Differently from axonal release, NMDAR activation was necessary for somatodendritic release to occur at physiological firing frequencies, acting thus as a gating mechanism by which activity-dependent release from these two neuronal compartments could be independently regulated. The NMDAR-mediated potentiation was independent of a specific firing pattern and was not accompanied by increased spike broadening, but correlated with higher dendritic Ca2+ levels. Our studies provide fundamental novel information regarding stimulus-secretion coupling at somatodendritic compartments, and shed light into mechanisms by which activity-dependent release of neuronal signals from axonal terminals and dendrites could be regulated in a spatially compartmentalized manner. ABSTRACT Dendrites are now recognized to be active transmitting neuronal compartments subserving complex brain functions, including motor behaviours and homeostatic neurohumoral responses. Still, the precise mechanisms underlying activity-dependent release of dendritic signals, and how dendritic release is regulated independently from axonal release, remains largely unknown. We used 'sniffer' biosensor cells to enable the measurement and study of activity-dependent dendritic release of vasopressin (VP) from hypothalamic neurones in brain slices. SnifferVP responses were dose-dependent, with a threshold detection level of 0.5 nM for VP, being thus a highly sensitive tool to detect endogenous physiological levels of the neuropeptide. Somatodendritic release of VP was rarely observed in response to a burst of action potentials fired in continuous mode, but was strengthened by clustered firing activity. Moreover, release evoked at any given frequency was robustly potentiated when firing was triggered by NMDA receptor (NMDAR) activation. Differently from axonal release, NMDAR activation was necessary for dendritic release to occur at physiological firing frequencies. Thus, we propose that NMDARs may act as a gating mechanism by which activity-dependent release from these two neuronal compartments can be independently regulated. The NMDAR-mediated potentiation of dendritic release was independent of a particular action potential waveform, firing pattern evoked, or a more pronounced spiked broadening, but correlated with higher dendritic Ca2+ levels. Overall, our studies provide fundamental novel information regarding stimulus-secretion coupling at neuronal dendrites, and shed light into mechanisms by which activity-dependent release of neuronal signals from axonal terminals and dendrites can be regulated in a spatially compartmentalized manner.
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Affiliation(s)
- Soledad Pitra
- Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Meng Zhang
- Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Edmund Cauley
- Department of Pharmacology and Physiology, George Washington University, Washington, DC, USA
| | - Javier E Stern
- Medical College of Georgia, Augusta University, Augusta, GA, USA
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Shen Y, Park JB, Lee SY, Han SK, Ryu PD. Exercise training normalizes elevated firing rate of hypothalamic presympathetic neurons in heart failure rats. Am J Physiol Regul Integr Comp Physiol 2018; 316:R110-R120. [PMID: 30485115 DOI: 10.1152/ajpregu.00225.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Exercise training (ExT) normalizes elevated sympathetic nerve activity in heart failure (HF), but the underlying mechanisms are not well understood. In this study, we examined the effects of 3 wk of ExT on the electrical activity of the hypothalamic presympathetic neurons in the brain slice of HF rats. HF rats were prepared by ligating the left descending coronary artery. The electrophysiological properties of paraventricular nucleus neurons projecting to the rostral ventrolateral medulla (PVN-RVLM) were examined using the slice patch-clamp technique. The neuronal firing rate was elevated in HF rats, and ExT induced a reduction in the firing rate ( P < 0.01). This ExT-induced decrease in the firing rate was associated with an increased frequency of spontaneous and miniature inhibitory postsynaptic current (IPSCs; P < 0.05). There was no significant change in excitatory postsynaptic current. Replacing Ca2+ with Mg2+ in the recording solution reduced the elevated IPSC frequency in HF rats with ExT ( P < 0.01) but not in those without ExT, indicating an increase in the probability of GABA release. In contrast, ExT did not restore the reduced GABAA receptor-mediated tonic inhibitory current in HF rats. A GABAA receptor blocker (bicuculline, 20 μM) increased the firing rate in HF rats with ExT ( P < 0.01) but not in those without ExT. Collectively, these results show that ExT normalized the elevated firing activity by increasing synaptic GABA release in PVN-RVLM neurons in HF rats. Our findings provide a brain mechanism underlying the beneficial effects of ExT in HF, which may shed light on the pathophysiology of other diseases accompanied by sympathetic hyperactivation.
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Affiliation(s)
- Yiming Shen
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul , Republic of Korea
| | - Jin Bong Park
- Department of Physiology, School of Medicine, Chungnam National University , Daejeon , Republic of Korea
| | - So Yeong Lee
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul , Republic of Korea
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Republic of Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul , Republic of Korea
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Shen Y, Han SK, Ryu PD. Comparison of electrophysiological properties of two types of pre-sympathetic neurons intermingled in the hypothalamic paraventricular nucleus. J Vet Sci 2018; 19:483-491. [PMID: 29649859 PMCID: PMC6070595 DOI: 10.4142/jvs.2018.19.4.483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/06/2018] [Accepted: 03/09/2018] [Indexed: 11/20/2022] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) contains two types of neurons projecting to either the rostral ventrolateral medulla (PVNRVLM) or the intermediolateral horn (IML) of the spinal cord (PVNIML). These two neuron groups are intermingled in the same subdivisions of the PVN and differentially regulate sympathetic outflow. However, electrophysiological evidence supporting such functional differences is largely lacking. Herein, we compared the electrophysiological properties of these neurons by using patch-clamp and retrograde-tracing techniques. Most neurons (>70%) in both groups spontaneously fired in the cell-attached mode. When compared to the PVNIML neurons, the PVNRVLM neurons had a lower firing rate and a more irregular firing pattern (p < 0.05). The PVNRVLM neurons showed smaller resting membrane potential, slower rise and decay times, and greater duration of spontaneous action potentials (p < 0.05). The PVNRVLM neurons received greater inhibitory synaptic inputs (frequency, p < 0.05) with a shorter rise time (p < 0.05). Taken together, the results indicate that the two pre-sympathetic neurons differ in their intrinsic and extrinsic electrophysiological properties, which may explain the lower firing activity of the PVNRVLM neurons. The greater inhibitory synaptic inputs to the PVNRVLM neurons also imply that these neurons have more integrative roles in regulation of sympathetic activity.
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Affiliation(s)
- Yiming Shen
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 54896, Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Science, Seoul National University, Seoul 08826, Korea
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Dos-Santos RC, Grover HM, Reis LC, Ferguson AV, Mecawi AS. Electrophysiological Effects of Ghrelin in the Hypothalamic Paraventricular Nucleus Neurons. Front Cell Neurosci 2018; 12:275. [PMID: 30210300 PMCID: PMC6121211 DOI: 10.3389/fncel.2018.00275] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/07/2018] [Indexed: 12/05/2022] Open
Abstract
The paraventricular nucleus (PVN) is involved in the control of sympathetic tone and the secretion of hormones, both functions known to be influenced by ghrelin, suggesting direct effect of ghrelin in this nucleus. However, the effects of ghrelin on the excitability of different PVN neuronal populations have not been demonstrated. This study assessed the effects of ghrelin on the activity of PVN neurons, correlating the responses to subpopulations of PVN neurons. We used a 64 multielectrode array to examine the effects of ghrelin administration on extracellular spike frequency in PVN neurons recorded in brain slices obtained from male Sprague-Dawley rats. Bath administration of 10 nM ghrelin increased (29/97, 30%) or decreased (37/97, 38%) spike frequency in PVN neurons. The GABAA and glutamate receptors antagonists abolish the decrease in spike frequency, without changes in the proportion of increases in spike frequency (23/53, 43%) induced by ghrelin. The results indicate a direct effect of ghrelin increasing PVN neurons activity and a synaptic dependent effect decreasing PVN neurons activity. The patch clamp recordings showed similar proportions of PVN neurons influenced by 10 nM ghrelin (33/95, 35% depolarized; 29/95, 30% hyperpolarized). Using electrophysiological fingerprints to identify specific subpopulations of PVN neurons we observed that the majority of pre-autonomic neurons (11/18 -61%) were depolarized by ghrelin, while both neuroendocrine (29% depolarizations, 40% hyperpolarizations), and magnocellular neurons (29% depolarizations, 21% hyperpolarizations) showed mixed responses. Finally, to correlate the electrophysiological response and the neurochemical phenotype of PVN neurons, cell cytoplasm was collected after recordings and RT-PCR performed to assess the presence of mRNA for vasopressin, oxytocin, thyrotropin (TRH) and corticotropin (CRH) releasing hormones. The single-cell RT-PCR showed that most TRH-expressing (4/5) and CRH-expressing (3/4) neurons are hyperpolarized in response to ghrelin. In conclusion, ghrelin either directly increases or indirectly decreases the activity of PVN neurons, this suggests that ghrelin acts on inhibitory PVN neurons that, in turn, decrease the activity of TRH-expressing and CRH-expressing neurons in the PVN.
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Affiliation(s)
- Raoni C Dos-Santos
- Department of Physiological Sciences, Institute of Biological and Health Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Hanna M Grover
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada
| | - Luís C Reis
- Department of Physiological Sciences, Institute of Biological and Health Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | | | - André S Mecawi
- Department of Physiological Sciences, Institute of Biological and Health Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil.,Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
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Kirchner MK, Foehring RC, Callaway J, Armstrong WE. Specificity in the interaction of high-voltage-activated Ca 2+ channel types with Ca 2+-dependent afterhyperpolarizations in magnocellular supraoptic neurons. J Neurophysiol 2018; 120:1728-1739. [PMID: 30020842 DOI: 10.1152/jn.00285.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnocellular oxytocin (OT) and vasopressin (VP) neurons express an afterhyperpolarization (AHP) following spike trains that attenuates firing rate and contributes to burst patterning. This AHP includes contributions from an apamin-sensitive, medium-duration AHP (mAHP) and from an apamin-insensitive, slow-duration AHP (sAHP). These AHPs are Ca2+ dependent and activated by Ca2+ influx through voltage-gated Ca2+ channels. Across central nervous system neurons that generate Ca2+-dependent AHPs, the Ca2+ channels that couple to the mAHP and sAHP differ greatly, but for magnocellular neurosecretory cells this relationship is unknown. Using simultaneous whole cell recording and Ca2+ imaging, we evaluated the effect of specific high-voltage-activated (HVA) Ca2+ channel blockers on the mAHP and sAHP. Block of all HVA channels via 400 μM Cd2+ inhibited almost the entire AHP. We tested nifedipine, conotoxin GVIA, agatoxin IVA, and SNX-482, specific blockers of L-, N-, P/Q-, and R-type channels, respectively. The N-type channel blocker conotoxin GVIA (1 μM) was the only toxin that inhibited the mAHP in either OT or VP neurons although the effect on VP neurons was weaker by comparison. The sAHP was significantly inhibited by N-type block in OT neurons and by R-type block in VP neurons although neither accounted for the entirety of the sAHP. Thus the mAHP appears to be elicited by Ca2+ from mostly N-type channels in both OT and VP neurons, but the contributions of specific Ca2+ channel types to the sAHP in each cell type are different. Alternative sources to HVA channels may contribute Ca2+ for the sAHP. NEW & NOTEWORTHY Despite the importance of afterhyperpolarization (AHP) mechanisms for regulating firing behavior of oxytocin (OT) and vasopressin (VP) neurons of supraoptic nucleus, which types of high-voltage-activated Ca2+ channels elicit AHPs in these cells was unknown. We found that N-type channels couple to the medium AHP in both cell types. For the slow AHP, N-type channels contribute in OT neurons, whereas R-type contribute in VP neurons. No single Ca2+ channel blocker abolished the entire AHP, suggesting that additional Ca2+ sources are involved.
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Affiliation(s)
- Matthew K Kirchner
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
| | - Robert C Foehring
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
| | - Joseph Callaway
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
| | - William E Armstrong
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
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Feetham CH, O'Brien F, Barrett-Jolley R. Ion Channels in the Paraventricular Hypothalamic Nucleus (PVN); Emerging Diversity and Functional Roles. Front Physiol 2018; 9:760. [PMID: 30034342 PMCID: PMC6043726 DOI: 10.3389/fphys.2018.00760] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022] Open
Abstract
The paraventricular nucleus of the hypothalamus (PVN) is critical for the regulation of homeostatic function. Although also important for endocrine regulation, it has been referred to as the "autonomic master controller." The emerging consensus is that the PVN is a multifunctional nucleus, with autonomic roles including (but not limited to) coordination of cardiovascular, thermoregulatory, metabolic, circadian and stress responses. However, the cellular mechanisms underlying these multifunctional roles remain poorly understood. Neurones from the PVN project to and can alter the function of sympathetic control regions in the medulla and spinal cord. Dysfunction of sympathetic pre-autonomic neurones (typically hyperactivity) is linked to several diseases including hypertension and heart failure and targeting this region with specific pharmacological or biological agents is a promising area of medical research. However, to facilitate future medical exploitation of the PVN, more detailed models of its neuronal control are required; populated by a greater compliment of constituent ion channels. Whilst the cytoarchitecture, projections and neurotransmitters present in the PVN are reasonably well documented, there have been fewer studies on the expression and interplay of ion channels. In this review we bring together an up to date analysis of PVN ion channel studies and discuss how these channels may interact to control, in particular, the activity of the sympathetic system.
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Affiliation(s)
- Claire H Feetham
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Fiona O'Brien
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Richard Barrett-Jolley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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Local Corticotropin-Releasing Factor Signaling in the Hypothalamic Paraventricular Nucleus. J Neurosci 2018; 38:1874-1890. [PMID: 29352046 DOI: 10.1523/jneurosci.1492-17.2017] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 12/13/2017] [Accepted: 12/19/2017] [Indexed: 01/28/2023] Open
Abstract
Corticotropin-releasing factor (CRF) neurons in the hypothalamic paraventricular nucleus (PVN) initiate hypothalamic-pituitary-adrenal axis activity through the release of CRF into the portal system as part of a coordinated neuroendocrine, autonomic, and behavioral response to stress. The recent discovery of neurons expressing CRF receptor type 1 (CRFR1), the primary receptor for CRF, adjacent to CRF neurons within the PVN, suggests that CRF also signals within the hypothalamus to coordinate aspects of the stress response. Here, we characterize the electrophysiological and molecular properties of PVN-CRFR1 neurons and interrogate their monosynaptic connectivity using rabies virus-based tracing and optogenetic circuit mapping in male and female mice. We provide evidence that CRF neurons in the PVN form synapses on neighboring CRFR1 neurons and activate them by releasing CRF. CRFR1 neurons receive the majority of monosynaptic input from within the hypothalamus, mainly from the PVN itself. Locally, CRFR1 neurons make GABAergic synapses on parvocellular and magnocellular cells within the PVN. CRFR1 neurons resident in the PVN also make long-range glutamatergic synapses in autonomic nuclei such as the nucleus of the solitary tract. Selective ablation of PVN-CRFR1 neurons in male mice elevates corticosterone release during a stress response and slows the decrease in circulating corticosterone levels after the cessation of stress. Our experiments provide evidence for a novel intra-PVN neural circuit that is activated by local CRF release and coordinates autonomic and endocrine function during stress responses.SIGNIFICANCE STATEMENT The hypothalamic paraventricular nucleus (PVN) coordinates concomitant changes in autonomic and neuroendocrine function to organize the response to stress. This manuscript maps intra-PVN circuitry that signals via CRF, delineates CRF receptor type 1 neuron synaptic targets both within the PVN and at distal targets, and establishes the role of this microcircuit in regulating hypothalamic-pituitary-adrenal axis activity.
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48
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Zhang M, Stern JE. Altered NMDA receptor-evoked intracellular Ca 2+ dynamics in magnocellular neurosecretory neurons of hypertensive rats. J Physiol 2017; 595:7399-7411. [PMID: 29034474 DOI: 10.1113/jp275169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/03/2017] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS NMDA receptor (NMDAR)-mediated Ca2+ signalling plays a critical role in modulating hypothalamic neurosecretory function. However, whether an altered NMDAR-evoked changes in Ca2+ (NMDAR-ΔCa2+ ) signalling in magnocellular neurosecretory cells (MNCs) may contribute to neurohumoral activation during disease states is unknown. We show that activation of NMDARs evoked similar inward currents in MNCs of sham and renovascular hypertensive (RVH) rats. Despite this, a prolonged and larger NMDAR-ΔCa2+ response was observed in the latter. The exacerbated NMDAR-ΔCa2+ responses in MNCs of RVH rats affected both somatic and dendritic compartments. Inhibition of the endoplasmic reticulum sarcoendoplasmic reticulum calcium trasport ATPase (SERCA) pump prolonged NMDAR-ΔCa2+ responses in sham rats, but not in RVH rats. Our study supports an altered spatiotemporal dynamic of NMDAR-ΔCa2+ signalling in MNCs from RVH rats, partly due to blunted endoplasmic reticulum Ca2+ buffering capacity. ABSTRACT A growing body of evidence supports an elevated NMDA receptor (NMDAR)-mediated glutamate excitatory function in the supraoptic nucleus and paraventricular nucleus of hypertensive rats that contributes to neurohumoral activation in this disease. However, the precise mechanisms underlying altered NMDAR signalling in hypertension remain to be elucidated. In this study, we performed simultaneous electrophysiology and fast confocal Ca2+ imaging to determine whether altered NMDAR-mediated changes in intracellular Ca2+ levels (NMDAR-ΔCa2+ ) occurred in hypothalamic magnocellular neurosecretory cells (MNCs) in renovascular hypertensive (RVH) rats. We found that despite evoking a similar excitatory inward current, activation of NMDARs resulted in a larger and prolonged ΔCa2+ in MNCs from RVH rats. Changes in NMDAR-ΔCa2+ dynamics were observed both in somatic and dendritic compartments. Inhibition of the sarcoendoplasmic reticulum calcium trasport ATPase (SERCA) pump activity with thapsigargin prolonged NMDAR-ΔCa2+ responses in MNCs of sham rats, but this effect was occluded in RVH rats, thus equalizing the magnitude and time course of the NMDA-ΔCa2+ responses between the two experimental groups. Taken together, our results support (1) an exacerbated NMDAR-ΔCa2+ response in somatodendritic compartments of MNCs of RVH rats, and (2) that a blunted ER Ca2+ buffering capacity contributes to the altered NMDAR-ΔCa2+ dynamics in this condition. Thus, altered spatiotemporal dynamics of the NMDAR-ΔCa2+ response stands as an underlying mechanism contributing to neurohumoral activation in neurogenic hypertension.
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Affiliation(s)
- Meng Zhang
- Department of Physiology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Javier E Stern
- Department of Physiology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
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Overactivity of Liver-Related Neurons in the Paraventricular Nucleus of the Hypothalamus: Electrophysiological Findings in db/db Mice. J Neurosci 2017; 37:11140-11150. [PMID: 29038244 DOI: 10.1523/jneurosci.1706-17.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/11/2017] [Accepted: 10/03/2017] [Indexed: 12/11/2022] Open
Abstract
Preautonomic neurons in the paraventricular nucleus (PVN) of the hypothalamus play a large role in the regulation of hepatic functions via the autonomic nervous system. Activation of hepatic sympathetic nerves increases glucose and lipid metabolism and contributes to the elevated hepatic glucose production observed in the type 2 diabetic condition. This augmented sympathetic output could originate from altered activity of liver-related PVN neurons. Remarkably, despite the importance of the brain-liver pathway, the cellular properties of liver-related neurons are not known. In this study, we provide the first evidence of overall activity of liver-related PVN neurons. Liver-related PVN neurons were identified with a retrograde, trans-synaptic, viral tracer in male lean and db/db mice and whole-cell patch-clamp recordings were conducted. In db/db mice, the majority of liver-related PVN neurons fired spontaneously; whereas, in lean mice the majority of liver-related PVN neurons were silent, indicating that liver-related PVN neurons are more active in db/db mice. Persistent, tonic inhibition was identified in liver-related PVN neurons; although, the magnitude of tonic inhibitory control was not different between lean and db/db mice. In addition, our study revealed that the transient receptor potential vanilloid type 1-dependent increase of excitatory neurotransmission was reduced in liver-related PVN neurons of db/db mice. These findings demonstrate plasticity of liver-related PVN neurons and a shift toward excitation in a diabetic mouse model. Our study suggests altered autonomic circuits at the level of the PVN, which can contribute to autonomic dysfunction and dysregulation of neural control of hepatic functions including glucose metabolism.SIGNIFICANCE STATEMENT A growing body of evidence suggests the importance of the autonomic control in the regulation of hepatic metabolism, which plays a major role in the development and progression of type 2 diabetes mellitus. Despite the importance of the brain-liver pathway, the overall activity of liver-related neurons in control and diabetic conditions is not known. This is a significant gap in knowledge, which prevents developing strategies to improve glucose homeostasis via altering the brain-liver pathway. One of the key findings of our study is the overall shift toward excitation in liver-related hypothalamic neurons in the diabetic condition. This overactivity may be one of the underlying mechanisms of elevated sympathetic activity known in metabolically compromised patients and animal models.
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Nongenomic Glucocorticoid Suppression of a Postsynaptic Potassium Current via Emergent Autocrine Endocannabinoid Signaling in Hypothalamic Neuroendocrine Cells following Chronic Dehydration. eNeuro 2017; 4:eN-NWR-0216-17. [PMID: 28966975 PMCID: PMC5617081 DOI: 10.1523/eneuro.0216-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/19/2017] [Accepted: 08/22/2017] [Indexed: 11/21/2022] Open
Abstract
Glucocorticoids rapidly stimulate endocannabinoid synthesis and modulation of synaptic transmission in hypothalamic neuroendocrine cells via a nongenomic signaling mechanism. The endocannabinoid actions are synapse-constrained by astrocyte restriction of extracellular spatial domains. Exogenous cannabinoids have been shown to modulate postsynaptic potassium currents, including the A-type potassium current (IA), in different cell types. The activity of magnocellular neuroendocrine cells is shaped by a prominent IA. We tested for a rapid glucocorticoid modulation of the postsynaptic IK and IA in magnocellular neuroendocrine cells of the hypothalamic paraventricular nucleus (PVN) using whole-cell recordings in rat brain slices. Application of the synthetic glucocorticoid dexamethasone (Dex) had no rapid effect on the IK or IA amplitude, voltage dependence, or kinetics in magnocellular neurons in slices from untreated rats. In magnocellular neurons from salt-loaded rats, however, Dex application caused a rapid suppression of the IA and a depolarizing shift in IA voltage dependence. Exogenously applied endocannabinoids mimicked the rapid Dex modulation of the IA, and CB1 receptor antagonists and agonists blocked and occluded the Dex-induced changes in the IA, respectively, suggesting an endocannabinoid dependence of the rapid glucocorticoid effect. Preincubation of control slices in a gliotoxin resulted in the partial recapitulation of the glucocorticoid-induced rapid suppression of the IA. These findings demonstrate a glucocorticoid suppression of the postsynaptic IA in PVN magnocellular neurons via an autocrine endocannabinoid-dependent mechanism following chronic dehydration, and suggest a possible role for astrocytes in the control of the autocrine endocannabinoid actions.
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