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Ruyle BC, Lima-Silveira L, Martinez D, Cummings KJ, Heesch CM, Kline DD, Hasser EM. Paraventricular nucleus projections to the nucleus tractus solitarii are essential for full expression of hypoxia-induced peripheral chemoreflex responses. J Physiol 2023; 601:4309-4336. [PMID: 37632733 DOI: 10.1113/jp284907] [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: 05/26/2023] [Accepted: 07/13/2023] [Indexed: 08/28/2023] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) is essential to peripheral chemoreflex neurocircuitry, but the specific efferent pathways utilized are not well defined. The PVN sends dense projections to the nucleus tractus solitarii (nTS), which exhibits neuronal activation following a hypoxic challenge. We hypothesized that nTS-projecting PVN (PVN-nTS) neurons contribute to hypoxia-induced nTS neuronal activation and cardiorespiratory responses. To selectively target PVN-nTS neurons, rats underwent bilateral nTS nanoinjection of retrogradely transported adeno-associated virus (AAV) driving Cre recombinase expression. We then nanoinjected into PVN AAVs driving Cre-dependent expression of Gq or Gi designer receptors exclusively activated by designer drugs (DREADDs) to test the degree that selective activation or inhibition, respectively, of the PVN-nTS pathway affects the hypoxic ventilatory response (HVR) of conscious rats. We used immunohistochemistry for Fos and extracellular recordings to examine how DREADD activation influences PVN-nTS neuronal activation by hypoxia. Pathway activation enhanced the HVR at moderate hypoxic intensities and increased PVN and nTS Fos immunoreactivity in normoxia and hypoxia. In contrast, PVN-nTS inhibition reduced both the HVR and PVN and nTS neuronal activation following hypoxia. To further confirm selective pathway effects on central cardiorespiratory output, rats underwent hypoxia before and after bilateral nTS nanoinjections of C21 to activate or inhibit PVN-nTS terminals. PVN terminal activation within the nTS enhanced tachycardic, sympathetic and phrenic (PhrNA) nerve activity responses to hypoxia whereas inhibition attenuated hypoxia-induced increases in nTS neuronal action potential discharge and PhrNA. The results demonstrate the PVN-nTS pathway enhances nTS neuronal activation and is necessary for full cardiorespiratory responses to hypoxia. KEY POINTS: The hypothalamic paraventricular nucleus (PVN) contributes to peripheral chemoreflex cardiorespiratory responses, but specific PVN efferent pathways are not known. The nucleus tractus solitarii (nTS) is the first integration site of the peripheral chemoreflex, and the nTS receives dense projections from the PVN. Selective GqDREADD activation of the PVN-nTS pathway was shown to enhance ventilatory responses to hypoxia and activation (Fos immunoreactivity (IR)) of nTS neurons in conscious rats, augmenting the sympathetic and phrenic nerve activity (SSNA and PhrNA) responses to hypoxia in anaesthetized rats. Selective GiDREADD inhibition of PVN-nTS neurons attenuates ventilatory responses, nTS neuronal Fos-IR, action potential discharge and PhrNA responses to hypoxia. These results demonstrate that a projection from the PVN to the nTS is critical for full chemoreflex responses to hypoxia.
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Affiliation(s)
- Brian C Ruyle
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
| | - Ludmila Lima-Silveira
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Diana Martinez
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Kevin J Cummings
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Cheryl M Heesch
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - David D Kline
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Eileen M Hasser
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
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2
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Anderson KL, Colón L, Doolittle V, Rosario Martinez R, Uraga J, Whitney O. Context-dependent activation of a social behavior brain network during learned vocal production. Brain Struct Funct 2023; 228:1785-1797. [PMID: 37615758 DOI: 10.1007/s00429-023-02693-0] [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: 02/14/2023] [Accepted: 08/01/2023] [Indexed: 08/25/2023]
Abstract
Neural activation in brain regions for vocal control is social context dependent. This context-dependent brain activation reflects social context-appropriate vocal behavior but has unresolved mechanisms. Studies of non-vocal social behaviors in multiple organisms suggest a functional role for several evolutionarily conserved and highly interconnected brain regions. Here, we use neural activity-dependent gene expression to evaluate the functional connectivity of this social behavior network within zebra finches in non-social and social singing contexts. We found that activity in one social behavior network region, the medial preoptic area (POM), was strongly associated with the amount of non-social undirected singing in zebra finches. In addition, in all regions of the social behavior network and the paraventricular nucleus (PVN), a higher percentage of EGR1 expression was observed during a social female-directed singing context compared to a non-social undirected singing context. Furthermore, we observed distinct patterns of significantly correlated activity between regions of the social behavior network during non-social undirected and social female-directed singing. Our results suggest that non-social vs. social contexts differentially activate this social behavior network and PVN. Moreover, neuronal activity within this social behavior network, PVN, and POM may alter context-appropriate vocal production.
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Affiliation(s)
- Katherine L Anderson
- Biology Department, City College, City University of New York, New York, NY, USA
- Graduate Center, Molecular, Cellular, and Developmental Biology Program, City University of New York, New York, NY, USA
| | - Lionel Colón
- Biology Department, City College, City University of New York, New York, NY, USA
| | - Violet Doolittle
- Biology Department, City College, City University of New York, New York, NY, USA
| | | | - Joseph Uraga
- Biology Department, City College, City University of New York, New York, NY, USA
| | - Osceola Whitney
- Biology Department, City College, City University of New York, New York, NY, USA.
- Graduate Center, Molecular, Cellular, and Developmental Biology Program, City University of New York, New York, NY, USA.
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Shin MG, Bae Y, Afzal R, Kondoh K, Lee EJ. Olfactory modulation of stress-response neural circuits. Exp Mol Med 2023; 55:1659-1671. [PMID: 37524867 PMCID: PMC10474124 DOI: 10.1038/s12276-023-01048-3] [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: 01/15/2023] [Revised: 04/20/2023] [Accepted: 04/30/2023] [Indexed: 08/02/2023] Open
Abstract
Stress responses, which are crucial for survival, are evolutionally conserved throughout the animal kingdom. The most common endocrine axis among stress responses is that triggered by corticotropin-releasing hormone neurons (CRHNs) in the hypothalamus. Signals of various stressors are detected by different sensory systems and relayed through individual neural circuits that converge on hypothalamic CRHNs to initiate common stress hormone responses. To investigate the neurocircuitry mechanisms underlying stress hormone responses induced by a variety of stressors, researchers have recently developed new approaches employing retrograde transsynaptic viral tracers, providing a wealth of information about various types of neural circuits that control the activity of CRHNs in response to stress stimuli. Here, we review earlier and more recent findings on the stress neurocircuits that converge on CRHNs, focusing particularly on olfactory systems that excite or suppress the activities of CRHNs and lead to the initiation of stress responses. Because smells are arguably the most important signals that enable animals to properly cope with environmental changes and survive, unveiling the regulatory mechanisms by which smells control stress responses would provide broad insight into how stress-related environmental cues are perceived in the animal brain.
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Affiliation(s)
- Min-Gi Shin
- Department of Brain Science, Ajou University School of Medicine, Suwon, 16499, Korea
- AI-Superconvergence KIURI Translational Research Center, Ajou University School of Medicine, Suwon, 16499, Korea
| | - Yiseul Bae
- Department of Brain Science, Ajou University School of Medicine, Suwon, 16499, Korea
| | - Ramsha Afzal
- Department of Brain Science, Ajou University School of Medicine, Suwon, 16499, Korea
| | - Kunio Kondoh
- Division of Endocrinology and Metabolism, Department of Homeostatic Regulation, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8585, Japan.
- Japan Science and Technology Agency, PRESTO, Okazaki, Aichi, 444-8585, Japan.
| | - Eun Jeong Lee
- Department of Brain Science, Ajou University School of Medicine, Suwon, 16499, Korea.
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4
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Anderson KL, Colón L, Doolittle V, Martinez RR, Uraga J, Whitney O. Context-dependent activation of a social behavior brain network associates with learned vocal production. RESEARCH SQUARE 2023:rs.3.rs-2587773. [PMID: 36824963 PMCID: PMC9949236 DOI: 10.21203/rs.3.rs-2587773/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
In zebra finches, an avian brain network for vocal control undergoes context-dependent patterning of song-dependent activation. Previous studies in zebra finches also implicate the importance of dopaminergic input in producing context-appropriate singing behavior. In mice, it has been shown that oxytocinergic neurons originated in the paraventricular nucleus of the hypothalamus (PVN) synapse directly onto dopamine neurons in the ventral tegmental area (VTA), implicating the necessity of oxytocin signaling from the PVN for producing a context-appropriate song. Both avian and non-avian axonal tract-tracing studies indicate high levels of PVN innervation by the social behavior network. Here, we hypothesize that the motivation for PVN oxytocin neurons to trigger dopamine release originates in the social behavior network, a highly conserved and interconnected collection of six regions implicated in various social and homeostatic behaviors. We found that expression of the neuronal activity marker EGR1 was not strongly correlated with song production in any of the regions of the social behavior network. However, when EGR1 expression levels were normalized to the singing rate, we found significantly higher levels of expression in the social behavior network regions except the medial preoptic area during a social female-directed singing context compared to a non-social undirected singing context. Our results suggest neuronal activity within the male zebra finch social behavior network influences the synaptic release of oxytocin from PVN onto dopaminergic projection neurons in the VTA, which in turn signals to the vocal control network to allow for context-appropriate song production.
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Cooper CM, Farrand AQ, Andresen MC, Beaumont E. Vagus nerve stimulation activates nucleus of solitary tract neurons via supramedullary pathways. J Physiol 2021; 599:5261-5279. [PMID: 34676533 PMCID: PMC11328930 DOI: 10.1113/jp282064] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/12/2021] [Indexed: 01/20/2023] Open
Abstract
Vagus nerve stimulation (VNS) treats patients with drug-resistant epilepsy, depression and heart failure, but the mechanisms responsible are uncertain. The mild stimulus intensities used in chronic VNS suggest activation of myelinated primary visceral afferents projecting to the nucleus of the solitary tract (NTS). Here, we monitored the activity of second and higher order NTS neurons in response to peripheral vagal activation using therapeutic VNS criteria. A bipolar stimulating electrode activated the left cervical vagus nerve, and stereotaxically placed single tungsten electrodes recorded unit activity from the left caudomedial NTS of chloralose-anaesthetized rats. High-intensity single electrical stimuli established vagal afferent conduction velocity (myelinated A-type or unmyelinated C-type) as well as synaptic order (second vs. higher order using paired electrical stimuli) for inputs to single NTS neurons. Then, VNS treatment was applied. A mid-collicular knife cut (KC) divided the brainstem from all supramedullary regions to determine their contribution to NTS activity. Our chief findings indicate that the KC reduced basal spontaneous activity of second-order NTS neurons receiving myelinated vagal input by 85%. In these neurons, acute VNS increased activity similarly in Control and KC animals. Interestingly, the KC interrupted VNS activation of higher order NTS neurons and second-order NTS neurons receiving unmyelinated vagal input, indicating that supramedullary descending projections to NTS are needed to amplify the peripheral neuronal signal from VNS. The present study begins to define the pathways activated during VNS and will help to better identify the central nervous system contributions to the therapeutic benefits of VNS therapy. KEY POINTS: Vagus nerve stimulation is routinely used in the clinic to treat epilepsy and depression, despite our uncertainty about how this treatment works. For this study, the connections between the nucleus of the solitary tract (NTS) and the higher brain regions were severed to learn more about their contribution to activity of these neurons during stimulation. Severing these brain connections reduced baseline activity as well as reducing stimulation-induced activation for NTS neurons receiving myelinated vagal input. Higher brain regions play a significant role in maintaining both normal activity in NTS and indirect mechanisms of enhancing NTS neuronal activity during vagus nerve stimulation.
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Affiliation(s)
- Coty M Cooper
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Ariana Q Farrand
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | | | - Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
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Malheiros-Lima MR, Silva TM, Takakura AC, Moreira TS. A5 noradrenergic-projecting C1 neurons activate sympathetic and breathing outputs in anaesthetized rats. Exp Physiol 2021; 107:147-160. [PMID: 34813109 DOI: 10.1113/ep089691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/16/2021] [Indexed: 12/18/2022]
Abstract
NEW FINDINGS What is the central question of this study? C1 neurons innervate pontine noradrenergic cell groups, including the A5 region: do A5 noradrenergic neurons contribute to the activation of sympathetic and respiratory responses produced by selective activation of the C1 group of neurons. What is the main finding and its importance? The increase in sympathetic and respiratory activities elicited by selective stimulation of C1 neurons is reduced after blockade of excitatory amino acid within the A5 region, suggesting that the C1-A5 pathway might be important for sympathetic-respiratory control. ABSTRACT Adrenergic C1 neurons innervate and excite pontine noradrenergic cell groups, including the ventrolateral pontine noradrenergic region (A5). Here, we tested the hypothesis that C1 activates A5 neurons through the release of glutamate and this effect is important for sympathetic and respiratory control. Using selective tools, we restricted the expression of channelrhodopsin2 under the control of the artificial promoter PRSx8 to C1 neurons (69%). Transduced catecholaminergic terminals within the A5 region are in contact with noradrenergic A5 neurons and the C1 terminals within the A5 region are predominantly glutamatergic. In a different group of animals, we performed retrograde lesion of C1 adrenergic neurons projecting to the A5 region with unilateral injection of the immunotoxin anti-dopamine β-hydroxylase-saporin (anti-DβH-SAP) directly into the A5 region during the hypoxic condition. As expected, hypoxia (8% O2 , 3 h) induced a robust increase in fos expression within the catecholaminergic C1 and A5 regions of the brainstem. Depletion of C1 cells projecting to the A5 regions reduced fos immunoreactivity induced by hypoxia within the C1 region. Physiological experiments showed that bilateral injection of kynurenic acid (100 mM) into the A5 region reduced the rise in mean arterial pressure, and sympathetic and phrenic nerve activities produced by optogenetic stimulation of C1 cells. In conclusion, the C1 neurons activate the ventrolateral pontine noradrenergic neurons (A5 region) possibly via the release of glutamate and might be important for sympathetic and respiratory outputs in anaesthetized rats.
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Affiliation(s)
- Milene R Malheiros-Lima
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
| | - Talita M Silva
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
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Sasaki K, Ferdousi F, Fukumitsu S, Kuwata H, Isoda H. Antidepressant- and anxiolytic-like activities of Rosmarinus officinalis extract in rodent models: Involvement of oxytocinergic system. Biomed Pharmacother 2021; 144:112291. [PMID: 34653760 DOI: 10.1016/j.biopha.2021.112291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Oxytocin (OXT), a neuropeptide involved in mammal reproductive and prosocial behaviors, has been reported to interact with various stressor-provoked neurobiological changes, including neuroendocrine, neurotransmitter, and inflammatory processes. In view of disturbances in psychosocial relationships due to social isolation and physical distancing measures amid the COVID-19 pandemic, being one of the triggering factors for the recent rise in depression and anxiety, OXT is a potential candidate for a new antidepressant. METHODS In this present study, we have aimed to investigate the effects of oral administration of Rosmarinus officinalis extract (RE), extracted from distillation residue of rosemary essential oil, on central OXT level in the context of other stress biomarkers and neurotransmitter levels in mice models. Tail suspension test (TST) and elevated plus maze test (EPMT) following LPS injection were employed to assess depressive- and anxiety-like behavior in mice, respectively. FINDINGS Pretreatment with RE for seven days significantly improved behavior in TST and EPMT. Whole-genome microarray analysis reveals that RE significantly reversed TST stress-induced alterations in gene expressions related to oxytocinergic and neurotransmitter pathways and inflammatory processes. In both models, RE significantly increased central Oxt and Oxtr expressions, as well as OXT protein levels. RE also significantly attenuated stress-induced changes in serum corticosterone, brain and serum BDNF levels, and brain neurotransmitters levels in both models. INTERPRETATION Altogether, our study is the first to report antidepressant- and anxiolytic-like activities of RE through modulating oxytocinergic system in mice brain and thus highlights the prospects of RE in the treatment of depressive disorders of psychosocial nature.
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Affiliation(s)
- Kazunori Sasaki
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Open Innovation Laboratory for Food and Medicinal Resource Engineering, National Institute of Advanced Industrial Science and Technology (AIST) and University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Farhana Ferdousi
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Open Innovation Laboratory for Food and Medicinal Resource Engineering, National Institute of Advanced Industrial Science and Technology (AIST) and University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Satoshi Fukumitsu
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Tsukuba Life Science Innovation Program (T-LSI), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8577 Ibaraki, Japan
| | - Hidetoshi Kuwata
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Hiroko Isoda
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Open Innovation Laboratory for Food and Medicinal Resource Engineering, National Institute of Advanced Industrial Science and Technology (AIST) and University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Tsukuba Life Science Innovation Program (T-LSI), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8577 Ibaraki, Japan.
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Povysheva N, Zheng H, Rinaman L. Glucagon-like peptide 1 receptor-mediated stimulation of a GABAergic projection from the bed nucleus of the stria terminalis to the hypothalamic paraventricular nucleus. Neurobiol Stress 2021; 15:100363. [PMID: 34277897 PMCID: PMC8271176 DOI: 10.1016/j.ynstr.2021.100363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 01/14/2023] Open
Abstract
We previously reported that GABAergic neurons within the ventral anterior lateral bed nucleus of the stria terminalis (alBST) express glucagon-like peptide 1 receptor (GLP1R) in rats, and that virally-mediated “knock-down” of GLP1R expression in the alBST prolongs the hypothalamic-pituitary-adrenal axis response to acute stress. Given other evidence that a GABAergic projection pathway from ventral alBST serves to limit stress-induced activation of the HPA axis, we hypothesized that GLP1 signaling promotes activation of GABAergic ventral alBST neurons that project directly to the paraventricular nucleus of the hypothalamus (PVN). After PVN microinjection of fluorescent retrograde tracer followed by preparation of ex vivo rat brain slices, whole-cell patch clamp recordings were made in identified PVN-projecting neurons within the ventral alBST. Bath application of Exendin-4 (a specific GLP1R agonist) indirectly depolarized PVN-projecting neurons in the ventral alBST and adjacent hypothalamic parastrial nucleus (PS) through a network-dependent increase in excitatory synaptic inputs, coupled with a network-independent reduction in inhibitory inputs. Additional retrograde tracing experiments combined with in situ hybridization confirmed that PVN-projecting neurons within the ventral alBST/PS are GABAergic, and do not express GLP1R mRNA. Conversely, GLP1R mRNA is expressed by a subset of neurons that project into the ventral alBST and were likely contained within coronal ex vivo slices, including GABAergic neurons within the oval subnucleus of the dorsal alBST and glutamatergic neurons within the substantia innominata. Our novel findings reveal potential GLP1R-mediated mechanisms through which the alBST exerts inhibitory control over the endocrine HPA axis.
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Affiliation(s)
- Nadya Povysheva
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Huiyuan Zheng
- Department of Psychology, Program in Neuroscience, Florida State University, Tallahassee, FL, 32306, USA
| | - Linda Rinaman
- Department of Psychology, Program in Neuroscience, Florida State University, Tallahassee, FL, 32306, USA
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Lefevre A, Benusiglio D, Tang Y, Krabichler Q, Charlet A, Grinevich V. Oxytocinergic Feedback Circuitries: An Anatomical Basis for Neuromodulation of Social Behaviors. Front Neural Circuits 2021; 15:688234. [PMID: 34194303 PMCID: PMC8236528 DOI: 10.3389/fncir.2021.688234] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/18/2021] [Indexed: 01/07/2023] Open
Abstract
Oxytocin (OT) is a neuropeptide produced by hypothalamic neurons and is known to modulate social behavior among other functions. Several experiments have shown that OT modulates neuronal activity in many brain areas, including sensory cortices. OT neurons thus project axons to various cortical and subcortical structures and activate neuronal subpopulations to increase the signal-to-noise ratio, and in turn, increases the saliency of social stimuli. Less is known about the origin of inputs to OT neurons, but recent studies show that cells projecting to OT neurons are often located in regions where the OT receptor (OTR) is expressed. Thus, we propose the existence of reciprocal connectivity between OT neurons and extrahypothalamic OTR neurons to tune OT neuron activity depending on the behavioral context. Furthermore, the latest studies have shown that OTR-expressing neurons located in social brain regions also project to other social brain regions containing OTR-expressing neurons. We hypothesize that OTR-expressing neurons across the brain constitute a common network coordinated by OT.
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Affiliation(s)
- Arthur Lefevre
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Diego Benusiglio
- European Molecular Biology Laboratory (EMBL), Epigenetics and Neurobiology Unit, Monterotondo, Italy
- Neuroscience and Behaviour Laboratory, Istituto Italiano di Tecnologia, Rome, Italy
| | - Yan Tang
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Quirin Krabichler
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Alexandre Charlet
- Centre National de la Recherche Scientifique (CNRS) and University of Strasbourg, Institute of Cellular and Integrative Neurosciences, Strasbourg, France
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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10
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Wang L, Yu CC, Li J, Tian Q, Du YJ. Mechanism of Action of Acupuncture in Obesity: A Perspective From the Hypothalamus. Front Endocrinol (Lausanne) 2021; 12:632324. [PMID: 33868169 PMCID: PMC8050351 DOI: 10.3389/fendo.2021.632324] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/16/2021] [Indexed: 01/22/2023] Open
Abstract
Obesity is a prevalent metabolic disease caused by an imbalance in food intake and energy expenditure. Although acupuncture is widely used in the treatment of obesity in a clinical setting, its mechanism has not been adequately elucidated. As the key pivot of appetite signals, the hypothalamus receives afferent and efferent signals from the brainstem and peripheral tissue, leading to the formation of a complex appetite regulation circuit, thereby effectively regulating food intake and energy homeostasis. This review mainly discusses the relationship between the hypothalamic nuclei, related neuropeptides, brainstem, peripheral signals, and obesity, as well as mechanisms of acupuncture on obesity from the perspective of the hypothalamus, exploring the current evidence and therapeutic targets for mechanism of action of acupuncture in obesity.
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Affiliation(s)
- Li Wang
- College of Acupuncture and Orthopedics, Hubei University of Chinese Medicine, Wuhan, China
| | - Chao-Chao Yu
- Department of Tuina, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
- The Fourth Clinical College, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Jia Li
- College of Acupuncture and Orthopedics, Hubei University of Chinese Medicine, Wuhan, China
| | - Qing Tian
- Department of Pathology and Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan-Jun Du
- College of Acupuncture and Orthopedics, Hubei University of Chinese Medicine, Wuhan, China
- *Correspondence: Yan-Jun Du,
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11
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Sharma NM, Liu X, Llewellyn TL, Katsurada K, Patel KP. Exercise training augments neuronal nitric oxide synthase dimerization in the paraventricular nucleus of rats with chronic heart failure. Nitric Oxide 2019; 87:73-82. [PMID: 30878404 PMCID: PMC6527363 DOI: 10.1016/j.niox.2019.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/06/2019] [Accepted: 03/08/2019] [Indexed: 12/20/2022]
Abstract
Exercise training (ExT) is an established non-pharmacological therapy that improves the health and quality of life in patients with chronic heart failure (CHF). Exaggerated sympathetic drive characterizes CHF due to an imbalance of the autonomic nervous system. Neuronal nitric oxide synthase (nNOS) in the paraventricular nucleus (PVN) produce nitric oxide (NO•), which is known to regulate the sympathetic tone. Previously we have shown that during CHF, the catalytically active dimeric form of nNOS is significantly decreased with a concurrent increase in protein inhibitor of nNOS (PIN) expression, a protein that dissociates dimeric nNOS to monomers and facilitates its degradation. Dimerization of nNOS also requires (6R)-5,6,7,8-tetrahydrobiopterin (BH4) for stability and activity. Previously, we have shown that ExT improves NO-mediated sympathetic inhibition in the PVN; however, the molecular mechanism remains elusive. We hypothesized; ExT restores the sympathetic drive by increasing the levels and catalytically active form of nNOS by abrogating changes in the PIN in the PVN of CHF rats. CHF was induced in adult male Sprague-Dawley rats by coronary artery ligation, which reliably mimics CHF in patients with myocardial infarction. After 4 weeks of surgery, Sham and CHF rats were subjected to 3 weeks of progressive treadmill exercise. ExT significantly (p < 0.05) decreased PIN expression and increased dimer/monomer ratio of nNOS in the PVN of rats with CHF. Moreover, we found decreased GTP cyclohydrolase 1(GCH1) expression: a rate-limiting enzyme for BH4 biosynthesis in the PVN of CHF rats suggesting that perhaps reduced BH4 availability may also contribute to decreased nNOS dimers. Interestingly, CHF induced decrease in GCH1 expression was increased with ExT. Our findings revealed that ExT rectified decreased PIN and GCH1 expression and increased dimer/monomer ratio of nNOS in the PVN, which may lead to increase NO• bioavailability resulting in amelioration of activated sympathetic drive during CHF.
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Affiliation(s)
- Neeru M Sharma
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA.
| | - Xuefei Liu
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
| | - Tamra L Llewellyn
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
| | - Kenichi Katsurada
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, UNMC, Omaha, NE 68198-5850, USA
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13
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Neural substrates of fear-induced hypophagia in male and female rats. Brain Struct Funct 2018; 223:2925-2947. [PMID: 29704225 DOI: 10.1007/s00429-018-1668-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 04/19/2018] [Indexed: 12/18/2022]
Abstract
Cessation of eating under fear is an adaptive response that aids survival by prioritizing the expression of defensive behaviors over feeding behavior. However, this response can become maladaptive when persistent. Thus, accurate mediation of the competition between fear and feeding is important in health and disease; yet, the underlying neural substrates are largely unknown. The current study identified brain regions that were recruited when a fear cue inhibited feeding in male and female rats. We used a previously established behavioral paradigm to elicit hypophagia with a conditioned cue for footshocks, and Fos imaging to map activation patterns during this behavior. We found that distinct patterns of recruitment were associated with feeding and fear expression, and that these patterns were similar in males and females except within the medial prefrontal cortex (mPFC). In both sexes, food consumption was associated with activation of cell groups in the central amygdalar nucleus, hypothalamus, and dorsal vagal complex, and exposure to food cues was associated with activation of the anterior basolateral amygdalar nucleus. In contrast, fear expression was associated with activation of the lateral and posterior basomedial amygdalar nuclei. Interestingly, selective recruitment of the mPFC in females, but not in males, was associated with both feeding and freezing behavior, suggesting sex differences in the neuronal processing underlying the competition between feeding and fear. This study provided the first evidence of the neural network mediating fear-induced hypophagia, and important functional activation maps for future interrogation of the underlying neural substrates.
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Blackburn MB, Andrade MA, Toney GM. Hypothalamic PVN contributes to acute intermittent hypoxia-induced sympathetic but not phrenic long-term facilitation. J Appl Physiol (1985) 2017; 124:1233-1243. [PMID: 29357503 DOI: 10.1152/japplphysiol.00743.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Blackburn MB, Andrade MA, Toney GM. Hypothalamic PVN contributes to acute intermittent hypoxia-induced sympathetic but not phrenic long-term facilitation. J Appl Physiol 124: 1233-1243, 2018. First published December 19, 2017; doi: 10.1152/japplphysiol.00743.2017 .- Acute intermittent hypoxia (AIH) repetitively activates the arterial chemoreflex and triggers a progressive increase of sympathetic nerve activity (SNA) and phrenic nerve activity (PNA) referred to as sympathetic and phrenic long-term facilitation (S-LTF and P-LTF), respectively. Neurons of the hypothalamic paraventricular nucleus (PVN) participate in the arterial chemoreflex, but their contribution to AIH-induced LTF is unknown. To determine this, anesthetized rats were vagotomized and exposed to 10 cycles of AIH, each consisting of ventilation for 3 min with 100% O2 followed by 3 min with 15% O2. Before AIH, rats received bilateral PVN injections of artificial cerebrospinal fluid (aCSF; vehicle) or the GABA-A receptor agonist muscimol (100 pmol in 50 nl) to inhibit neuronal activity. Thirty minutes after completing the AIH protocol, during which rats were continuously ventilated with 100% O2, S-LTF and P-LTF were quantified from recordings of integrated splanchnic SNA and PNA, respectively. PVN muscimol attenuated increases of SNA during hypoxic episodes occurring in later cycles (6-10) of AIH ( P < 0.03) and attenuated post-AIH S-LTF ( P < 0.001). Muscimol, however, did not consistently affect peak PNA responses during hypoxic episodes and did not alter AIH-induced P-LTF. These findings indicate that PVN neuronal activity contributes to sympathetic responses during AIH and to subsequent generation of S-LTF. NEW & NOTEWORTHY Neural circuits mediating acute intermittent hypoxia (AIH)-induced sympathetic and phrenic long-term facilitation (LTF) have not been fully elucidated. We found that paraventricular nucleus (PVN) inhibition attenuated sympathetic activation during episodes of AIH and reduced post-AIH sympathetic LTF. Neither phrenic burst patterning nor the magnitude of AIH-induced phrenic LTF was affected. Findings indicate that PVN neurons contribute to AIH-induced sympathetic LTF. Defining mechanisms of sympathetic LTF could improve strategies to reduce sympathetic activity in cardiovascular and metabolic diseases.
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Affiliation(s)
- Megan B Blackburn
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Mary Ann Andrade
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas
| | - Glenn M Toney
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio , San Antonio, Texas.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio , San Antonio, Texas
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Dumont AS, Nemergut EC, Jane JA, Laws ER. Postoperative Care Following Pituitary Surgery. J Intensive Care Med 2016; 20:127-40. [PMID: 15888900 DOI: 10.1177/0885066605275247] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Patients undergoing surgery for pituitary tumors represent a heterogeneous population each with unique clinical, biochemical, radiologic, pathologic, neurologic, and/or ophthalmologic considerations. The postoperative management of patients following pituitary surgery often occurs in the context of a dynamic state of the hypothalamic-pituitary-end organ axis. Consequently, a significant component of the postoperative care of these patients focuses on vigilant screening and observation for neuroendocrinologic perturbations such as varying degrees of hypopituitarism and disorders of water balance (diabetes insipidus and the syndrome of inappropriate antidiuretic hormone). Additionally, one must be cognizant of other potential complications specific to the transsphenoidal approach for tumor removal including cerebrospinal fluid leakage and meningitis. This review addresses the postoperative management of patients undergoing pituitary surgery with an emphasis on careful screening and recognition of complications.
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Affiliation(s)
- Aaron S Dumont
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, 22908, USA
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Dwarkasing JT, Marks DL, Witkamp RF, van Norren K. Hypothalamic inflammation and food intake regulation during chronic illness. Peptides 2016; 77:60-6. [PMID: 26158772 DOI: 10.1016/j.peptides.2015.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 05/14/2015] [Accepted: 06/22/2015] [Indexed: 02/08/2023]
Abstract
Anorexia is a common symptom in chronic illness. It contributes to malnutrition and strongly affects survival and quality of life. A common denominator of many chronic diseases is an elevated inflammatory status, which is considered to play a pivotal role in the failure of food-intake regulating systems in the hypothalamus. In this review, we summarize findings on the role of hypothalamic inflammation on food intake regulation involving hypothalamic neuropeptide Y (NPY) and pro-opiomelanocortin (POMC). Furthermore, we outline the role of serotonin in the inability of these peptide based food-intake regulating systems to respond and adapt to changes in energy metabolism during chronic disease.
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Affiliation(s)
- J T Dwarkasing
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
| | - D L Marks
- Department of Pediatric Endocrinology, Oregon Health & Sciences University, Portland, OR 97201, USA
| | - R F Witkamp
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - K van Norren
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands; Nutricia Research, Utrecht, The Netherlands
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17
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Abstract
Although it has been known for more than a century that the brain controls overall energy balance and adiposity by regulating feeding behavior and energy expenditure, the roles for individual brain regions and neuronal subtypes were not fully understood until recently. This area of research is active, and as such our understanding of the central regulation of energy balance is continually being refined as new details emerge. Much of what we now know stems from the discoveries of leptin and the hypothalamic melanocortin system. Hypothalamic circuits play a crucial role in the control of feeding and energy expenditure, and within the hypothalamus, the arcuate nucleus (ARC) functions as a gateway for hormonal signals of energy balance, such as leptin. It is also well established that the ARC is a primary residence for hypothalamic melanocortinergic neurons. The paraventricular hypothalamic nucleus (PVH) receives direct melanocortin input, along with other integrated signals that affect energy balance, and mediates the majority of hypothalamic output to control both feeding and energy expenditure. Herein, we review in detail the structure and function of the ARC-PVH circuit in mediating leptin signaling and in regulating energy balance.
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Affiliation(s)
- Amy K Sutton
- Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48105;
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48105;
| | - Martin G Myers
- Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48105;
| | - David P Olson
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48105;
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King TL, Ruyle BC, Kline DD, Heesch CM, Hasser EM. Catecholaminergic neurons projecting to the paraventricular nucleus of the hypothalamus are essential for cardiorespiratory adjustments to hypoxia. Am J Physiol Regul Integr Comp Physiol 2015; 309:R721-31. [PMID: 26157062 PMCID: PMC4666929 DOI: 10.1152/ajpregu.00540.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 07/01/2015] [Indexed: 12/31/2022]
Abstract
Brainstem catecholamine neurons modulate sensory information and participate in control of cardiorespiratory function. These neurons have multiple projections, including to the paraventricular nucleus (PVN), which contributes to cardiorespiratory and neuroendocrine responses to hypoxia. We have shown that PVN-projecting catecholaminergic neurons are activated by hypoxia, but the function of these neurons is not known. To test the hypothesis that PVN-projecting catecholamine neurons participate in responses to respiratory challenges, we injected IgG saporin (control; n = 6) or anti-dopamine β-hydroxylase saporin (DSAP; n = 6) into the PVN to retrogradely lesion catecholamine neurons projecting to the PVN. After 2 wk, respiratory measurements (plethysmography) were made in awake rats during normoxia, increasing intensities of hypoxia (12, 10, and 8% O2) and hypercapnia (5% CO2-95% O2). DSAP decreased the number of tyrosine hydroxylase-immunoreactive terminals in PVN and cells counted in ventrolateral medulla (VLM; -37%) and nucleus tractus solitarii (nTS; -36%). DSAP produced a small but significant decrease in respiratory rate at baseline (during normoxia) and at all intensities of hypoxia. Tidal volume and minute ventilation (VE) index also were impaired at higher hypoxic intensities (10-8% O2; e.g., VE at 8% O2: IgG = 181 ± 22, DSAP = 91 ± 4 arbitrary units). Depressed ventilation in DSAP rats was associated with significantly lower arterial O2 saturation at all hypoxic intensities. PVN DSAP also reduced ventilatory responses to 5% CO2 (VE: IgG = 176 ± 21 and DSAP = 84 ± 5 arbitrary units). Data indicate that catecholamine neurons projecting to the PVN are important for peripheral and central chemoreflex respiratory responses and for maintenance of arterial oxygen levels during hypoxic stimuli.
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Affiliation(s)
| | | | - David D Kline
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, and
| | - Cheryl M Heesch
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, and
| | - Eileen M Hasser
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, and Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
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19
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Aguilera G. Regulation of the hypothalamic-pituitary-adrenal axis by neuropeptides. Horm Mol Biol Clin Investig 2015; 7:327-36. [PMID: 25961271 DOI: 10.1515/hmbci.2011.123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 09/12/2011] [Indexed: 01/01/2023]
Abstract
The major endocrine response to stress occurs via activation of the hypothalamic-pituitary-adrenal (HPA) axis, leading ultimately to increases in circulating glucocorticoids, which are essential for the metabolic adaptation to stress. The major players in the HPA axis are the hypothalamic neuropeptide, corticotropin releasing hormone (CRH), the pituitary hormone adrenocorticotropic hormone, and the negative feedback effects of adrenal glucocorticoids. In addition, a number of other neuropeptides, including vasopressin (VP), angiotensin II, oxytocin, pituitary adenylate cyclase activating peptide, orexin and cholecystokinin, and nesfatin can affect HPA axis activity by influencing the expression and secretion of CRH, and also by modulating pituitary corticotroph function or adrenal steroidogenesis. Of these peptides, VP co-secreted with CRH from axonal terminals in the external zone of the median eminence plays a prominent role by potentiating the stimulatory effect of CRH and by increasing the number of pituitary corticotrophs during chronic challenge. Although the precise role and significance of many of these neuropeptides in regulating HPA axis activity requires further investigation, it is likely that they are part of a multifactorial system mediating the fine tuning of HPA axis activity during adaptation to a variety of physiological and stressful conditions.
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20
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Radler ME, Wright BJ, Walker FR, Hale MW, Kent S. Calorie restriction increases lipopolysaccharide-induced neuropeptide Y immunolabeling and reduces microglial cell area in the arcuate hypothalamic nucleus. Neuroscience 2014; 285:236-47. [PMID: 25446356 DOI: 10.1016/j.neuroscience.2014.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/20/2014] [Accepted: 11/04/2014] [Indexed: 11/30/2022]
Abstract
Calorie restriction (CR) increases longevity and elicits many health promoting benefits including delaying immunosenescence and reducing the incidence of age-related diseases. Although the mechanisms underlying the health-enhancing effects of CR are not known, a likely contributing factor is alterations in immune system functioning. CR suppresses lipopolysaccharide (LPS)-induced release of pro-inflammatory cytokines, blocks LPS-induced fever, and shifts hypothalamic signaling pathways to an anti-inflammatory bias. Furthermore, we have recently shown that CR attenuates LPS-stimulated microglial activation in the hypothalamic arcuate nucleus (ARC), a brain region containing neurons that synthesize neuropeptide Y (NPY), an orexigenic neuropeptide that is upregulated by a CR diet and has anti-inflammatory properties. To determine if increased NPY expression in the ARC following CR was associated with changes in microglial activation, a set of brain sections from mice that were exposed to 50% CR or ad libitum feeding for 28 days before being injected with LPS were immunostained for NPY. The density of NPY-immunolabeling was assessed across the rostrocaudal extent of the ARC and hypothalamic paraventricular nucleus (PVN). An adjacent set of sections were immunostained for ionized calcium-binding adapter molecule-1 (Iba1) and immunostained microglia in the ARC were digitally reconstructed to investigate the effects of CR on microglial morphology. We demonstrated that exposure to CR increased NPY expression in the ARC, but not the PVN. Digital reconstruction of microglia revealed that LPS increased Iba1 intensity in ad libitum fed mice but had no effect on Iba1 intensity in CR mice. CR also decreased the size of ARC microglial cells following LPS. Correlational analyses revealed strong associations between NPY and body temperature, and body temperature and microglia area. Together these results suggest that CR-induced changes in NPY are not directly involved in the suppression of LPS-induced microglial activation, however, NPY may indirectly affect microglial morphology through changes in body temperature.
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Affiliation(s)
- M E Radler
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - B J Wright
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - F R Walker
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, NSW, Australia
| | - M W Hale
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - S Kent
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia.
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21
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Veening J, Coolen L. Neural mechanisms of sexual behavior in the male rat: Emphasis on ejaculation-related circuits. Pharmacol Biochem Behav 2014; 121:170-83. [DOI: 10.1016/j.pbb.2013.12.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 12/12/2013] [Accepted: 12/16/2013] [Indexed: 01/20/2023]
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MacDonald K, Feifel D. Oxytocin's role in anxiety: a critical appraisal. Brain Res 2014; 1580:22-56. [PMID: 24468203 DOI: 10.1016/j.brainres.2014.01.025] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/21/2013] [Accepted: 01/15/2014] [Indexed: 12/16/2022]
Abstract
A growing literature suggests that the oxytocin (OT) system may play a role in human anxiety states, anxiety-related traits, and moreover, that this system may be a target for the development of novel anxiolytic treatments. However, studies of OT's acute and chronic effects on various aspects of anxiety have produced mixed results. In this forward-looking review, we discuss the myriad phenomena to which the term "anxiety" is applied in the OT literature and the problem this presents developing a coherent picture of OT's role in anxiety. We then survey several different fields of research that support the role of the OT system in human anxiety, including evolutionary perspectives, translational and neuroimaging research, genetic studies, and clinical trials of intranasal OT. As an outgrowth of this data, we propose a "bowtie" model of OT's role at the interface of social attachment and anxiety. We next direct attention to understudied brain regions and neural circuits which may be important to study in OT experiments in humans anxiety disorders. Finally, we conclude by proposing questions and priorities for studying both the clinical potential of OT in anxiety, as well as mechanisms that may underlie this potential. Crucially, these priorities include targeted proof-of-concept clinical trials of IN OT in certain anxiety disorders, including investigations of individual moderators of OT's anxiolytic effects (i.e. sex, genetic factors, and early experience). This article is part of a Special Issue entitled Oxytocin and Social Behav.
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Affiliation(s)
- Kai MacDonald
- University of San Diego, Department of Psychiatry, 140 Arbor Drive, CA 92103, USA.
| | - David Feifel
- University of San Diego, Department of Psychiatry, 140 Arbor Drive, CA 92103, USA
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Mason BL, Wang Q, Zigman JM. The central nervous system sites mediating the orexigenic actions of ghrelin. Annu Rev Physiol 2013; 76:519-33. [PMID: 24111557 DOI: 10.1146/annurev-physiol-021113-170310] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The peptide hormone ghrelin is important for both homeostatic and hedonic eating behaviors, and its orexigenic actions occur mainly via binding to the only known ghrelin receptor, the growth hormone secretagogue receptor (GHSR). GHSRs are located in several distinct regions of the central nervous system. This review discusses those central nervous system sites that have been found to play critical roles in the orexigenic actions of ghrelin, including hypothalamic nuclei, the hippocampus, the amygdala, the caudal brain stem, and midbrain dopaminergic neurons. Hopefully, this review can be used as a stepping stone for the reader wanting to gain a clearer understanding of the central nervous system sites of direct ghrelin action on feeding behavior, and as inspiration for future studies to provide an even-more-detailed map of the neurocircuitry controlling eating and body weight.
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Affiliation(s)
- B L Mason
- Departments of Internal Medicine (Divisions of Hypothalamic Research and of Endocrinology & Metabolism) and Psychiatry, The University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077; , ,
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King TL, Kline DD, Ruyle BC, Heesch CM, Hasser EM. Acute systemic hypoxia activates hypothalamic paraventricular nucleus-projecting catecholaminergic neurons in the caudal ventrolateral medulla. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1112-23. [PMID: 24049118 DOI: 10.1152/ajpregu.00280.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hypoxia activates catecholamine neurons in the caudal ventrolateral medulla (CVLM). The hypothalamic paraventricular nucleus (PVN) modulates arterial chemoreflex responses and receives catecholaminergic projections from the CVLM, but it is not known whether the CVLM-PVN projection is activated by chemoreflex stimulation. We hypothesized that acute hypoxia (AH) activates PVN-projecting catecholaminergic neurons in the CVLM. Fluoro-Gold (2%, 60-90 nl) was microinjected into the PVN of rats to retrogradely label CVLM neurons. After recovery, conscious rats underwent 3 h of normoxia (21% O2, n = 4) or AH (12, 10, or 8% O2; n = 5 each group). We used Fos immunoreactivity as an index of CVLM neuronal activation and tyrosine hydroxylase (TH) immunoreactivity to identify catecholaminergic neurons. Positively labeled neurons were counted in six caudal-rostral sections containing CVLM. Hypoxia progressively increased the number of Fos-immunoreactive CVLM cells (21%, 19 ± 6; 12%, 49 ± 2; 10%, 117 ± 8; 8%, 179 ± 7; P < 0.001). Catecholaminergic cells colabeled with Fos immunoreactivity in the CVLM were observed following 12% O2, and further increases in hypoxia severity caused markedly more activation. PVN-projecting CVLM cells were activated following more severe hypoxia (10% and 8% O2). A large proportion (89 ± 3%) of all activated PVN-projecting CVLM neurons were catecholaminergic, regardless of hypoxia intensity. Data suggest that catecholaminergic, PVN-projecting CVLM neurons are particularly hypoxia-sensitive, and these neurons may be important in the cardiorespiratory and/or neuroendocrine responses elicited by the chemoreflex.
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Affiliation(s)
- T Luise King
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
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Gautron L, Cravo RM, Elmquist JK, Elias CF. Discrete melanocortin-sensitive neuroanatomical pathway linking the ventral premmamillary nucleus to the paraventricular hypothalamus. Neuroscience 2013; 240:70-82. [PMID: 23485805 DOI: 10.1016/j.neuroscience.2013.02.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 02/14/2013] [Accepted: 02/15/2013] [Indexed: 11/16/2022]
Abstract
The physiological effects of melanocortin-4 receptor (MC4-R) on metabolism have been hypothesized to be mediated individually or collectively by neuronal groups innervating the paraventricular nucleus of the hypothalamus (PVH). The present study was designed to identify MC4-R-expressing neurons that innervate the PVH using retrograde tract tracing techniques in the MC4-R-GFP reporter mice. Our initial mapping identified very limited projections from MC4-R-expressing neurons to the PVH. This included a defined population of MC4-R-positive neurons located in the ventral premmamillary nucleus (PMv). Anterograde tracing experiments confirmed projections from PMv neurons to the medial parvicellular subdivision of the PVH, in close proximity to oxytocin neurons and β-endorphin-containing fibers. Given the known stimulatory effects of leptin and sexual odorants exposure on many PMv neurons, it was expected that MC4-R-expressing neurons in the PMv might be responsive to leptin and activated by odors exposure. Contrary to expectation, MC4-R-GFP neurons in the PMv do not respond to leptin as demonstrated by double labeling for GFP and leptin-induced phosphorylated STAT3. However, we found that Fos expression is induced in a large subset of MC4-R-GFP neurons in the PMv in response to opposite sex odors. Collectively, these results provide evidence for a previous unrecognized role of MC4-R expressed by neurons innervating the PVH that are also sensitive to reproductive cues.
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Affiliation(s)
- L Gautron
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, USA.
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Mirzoyan EA, Khudaverdyan DN, Hasratyan HA. The electrophysiological study of changes in the activities of locus coeruleus neurons under conditions of parathyroidectomy and parathyroid hormone administration. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712412010060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Balasubramanian P, Sirivelu MP, Weiss KA, Wagner JG, Harkema JR, Morishita M, Mohankumar PS, Mohankumar SMJ. Differential effects of inhalation exposure to PM2.5 on hypothalamic monoamines and corticotrophin releasing hormone in lean and obese rats. Neurotoxicology 2012; 36:106-11. [PMID: 22426024 DOI: 10.1016/j.neuro.2012.02.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 02/21/2012] [Accepted: 02/27/2012] [Indexed: 12/21/2022]
Abstract
Acute exposure to airborne pollutants, especially particulate matter (PM2.5) is known to increase hospital admissions for cardiovascular conditions, increase cardiovascular related mortality and predispose the elderly and obese individuals to cardiovascular conditions. The mechanisms by which PM2.5 exposure affects the cardiovascular system is not clear. Since the autonomic system plays an important role in cardiovascular regulation, we hypothesized that PM2.5 exposure most likely activates the paraventricular nucleus (PVN) of the hypothalamus to cause an increase in sympathetic nervous system and/or stress axis activity. We also hypothesized that these changes may be sustained in obese rats predisposing them to higher cardiovascular risk. To test this, adult male Brown Norway (BN) rats were subjected to one day or three days of inhalation exposures to filtered air (FA) or concentrated air particulate (CAP) derived from ambient PM2.5. Corpulent JCR-LA rats were exposed to FA or CAP for four days. Animals were sacrificed 24h after the last inhalation exposure. Their brains were removed, frozen and sectioned. The PVN and median eminence (ME) were microdissected. PVN was analyzed for norepinephrine (NE), dopamine (DA) and 5-hydroxy-indole acetic acid (5-HIAA) levels using HPLC-EC. ME was analyzed for corticotrophin releasing hormone (CRH) levels by ELISA. One day exposure to CAP increased NE levels in the PVN and CRH levels in the ME of BN rats. Repeated exposures to CAP did not affect NE levels in the PVN of BN rats, but increased NE levels in JCR/LA rats. A similar pattern was observed with 5-HIAA levels. DA levels on the other hand, were unaffected in both BN and JCR/LA strains. These data suggest that repeated exposures to PM2.5 continue to stimulate the PVN in obese animals but not lean rats.
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Affiliation(s)
- Priya Balasubramanian
- Department of Pharmacology and Toxicology, College of Veterinary Medicine, Michigan State University, E. Lansing, MI 48824, United States
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King TL, Heesch CM, Clark CG, Kline DD, Hasser EM. Hypoxia activates nucleus tractus solitarii neurons projecting to the paraventricular nucleus of the hypothalamus. Am J Physiol Regul Integr Comp Physiol 2012; 302:R1219-32. [PMID: 22403798 DOI: 10.1152/ajpregu.00028.2012] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Peripheral chemoreceptor afferent information is sent to the nucleus tractus solitarii (nTS), integrated, and relayed to other brain regions to alter cardiorespiratory function. The nTS projects to the hypothalamic paraventricular nucleus (PVN), but activation and phenotype of these projections during chemoreflex stimulation is unknown. We hypothesized that activation of PVN-projecting nTS neurons occurs primarily at high intensities of hypoxia. We assessed ventilation and cardiovascular parameters in response to increasing severities of hypoxia. Retrograde tracers were used to label nTS PVN-projecting neurons and, in some rats, rostral ventrolateral medulla (RVLM)-projecting neurons. Immunohistochemistry was performed to identify nTS cells that were activated (Fos-immunoreactive, Fos-IR), catecholaminergic, and GABAergic following hypoxia. Conscious rats underwent 3 h normoxia (n = 4, 21% O(2)) or acute hypoxia (12, 10, or 8% O(2); n = 5 each). Hypoxia increased ventilation and the number of Fos-IR nTS cells (21%, 13 ± 2; 12%, 58 ± 4; 10%, 166 ± 22; 8%, 186 ± 6). Fos expression after 10% O(2) was similar whether arterial pressure was allowed to decrease (-13 ± 1 mmHg) or was held constant. The percentage of PVN-projecting cells activated was intensity dependent, but contrary to our hypothesis, PVN-projecting nTS cells exhibiting Fos-IR were found at all hypoxic intensities. Notably, at all intensities of hypoxia, ∼75% of the activated PVN-projecting nTS neurons were catecholaminergic. Compared with RVLM-projecting cells, a greater percentage of PVN-projecting nTS cells was activated by 10% O(2). Data suggest that increasing hypoxic intensity activates nTS PVN-projecting cells, especially catecholaminergic, PVN-projecting neurons. The nTS to PVN catecholaminergic pathway may be critical even at lower levels of chemoreflex activation and more important to cardiorespiratory responses than previously considered.
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Affiliation(s)
- T Luise King
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri 65211, USA
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Llewellyn T, Zheng H, Liu X, Xu B, Patel KP. Median preoptic nucleus and subfornical organ drive renal sympathetic nerve activity via a glutamatergic mechanism within the paraventricular nucleus. Am J Physiol Regul Integr Comp Physiol 2012; 302:R424-32. [PMID: 22160544 PMCID: PMC3293509 DOI: 10.1152/ajpregu.00403.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 12/01/2011] [Indexed: 11/22/2022]
Abstract
The paraventricular nucleus (PVN) of the hypothalamus is involved in the neural control of sympathetic drive, but the precise mechanism(s) that influences the PVN is not known. The activation of the PVN may be influenced by input from higher forebrain areas, such as the median preoptic nucleus (MnPO) and the subfornical organ (SFO). We hypothesized that activation of the MnPO or SFO would drive the PVN through a glutamatergic pathway. Neuroanatomical connections were confirmed by the recovery of a retrograde tracer in the MnPO and SFO that was injected bilaterally into the PVN in rats. Microinjection of 200 pmol of N-methyl-d-aspartate (NMDA) or bicuculline-induced activation of the MnPO and increased renal sympathetic activity (RSNA), mean arterial pressure, and heart rate in anesthetized rats. These responses were attenuated by prior microinjection of a glutamate receptor blocker AP5 (4 nmol) into the PVN (NMDA - ΔRSNA 72 ± 8% vs. 5 ± 1%; P < 0.05). Using single-unit extracellular recording, we examined the effect of NMDA microinjection (200 pmol) into the MnPO on the firing activity of PVN neurons. Of the 11 active neurons in the PVN, 6 neurons were excited by 95 ± 17% (P < 0.05), 1 was inhibited by 57%, and 4 did not respond. The increased RSNA after activation of the SFO by ANG II (1 nmol) or bicuculline (200 pmol) was also reduced by AP5 in the PVN (for ANG II - ΔRSNA 46 ± 7% vs. 17 ± 4%; P < 0.05). Prior microinjection of ANG II type 1 receptor blocker losartan (4 nmol) into the PVN did not change the response to ANG II or bicuculline microinjection into the SFO. The results from this study demonstrate that the sympathoexcitation mediated by a glutamatergic mechanism in the PVN is partially driven by the activation of the MnPO or SFO.
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Affiliation(s)
- Tamra Llewellyn
- Dept. of Cellular and Integrative Physiology, Univ. of Nebraska Medical Center, Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Knobloch H, Charlet A, Hoffmann L, Eliava M, Khrulev S, Cetin A, Osten P, Schwarz M, Seeburg P, Stoop R, Grinevich V. Evoked Axonal Oxytocin Release in the Central Amygdala Attenuates Fear Response. Neuron 2012; 73:553-66. [DOI: 10.1016/j.neuron.2011.11.030] [Citation(s) in RCA: 748] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2011] [Indexed: 01/26/2023]
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Guo JD, Hazra R, Dabrowska J, Muly EC, Wess J, Rainnie DG. Presynaptic muscarinic M(2) receptors modulate glutamatergic transmission in the bed nucleus of the stria terminalis. Neuropharmacology 2011; 62:1671-83. [PMID: 22166222 DOI: 10.1016/j.neuropharm.2011.11.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/22/2011] [Accepted: 11/24/2011] [Indexed: 10/14/2022]
Abstract
The anterolateral cell group of the bed nucleus of the stria terminalis (BNST(ALG)) serves as an important relay station in stress circuitry. Limbic inputs to the BNST(ALG) are primarily glutamatergic and activity-dependent changes in this input have been implicated in abnormal behaviors associated with chronic stress and addiction. Significantly, local infusion of acetylcholine (ACh) receptor agonists into the BNST trigger stress-like cardiovascular responses, however, little is known about the effects of these agents on glutamatergic transmission in the BNST(ALG). Here, we show that glutamate- and ACh-containing fibers are found in close association in the BNST(ALG). Moreover, in the presence of the acetylcholinesterase inhibitor, eserine, endogenous ACh release evoked a long-lasting reduction of the amplitude of stimulus-evoked EPSCs. This effect was mimicked by exogenous application of the ACh analog, carbachol, which caused a reversible, dose-dependent, reduction of the evoked EPSC amplitude, and an increase in both the paired-pulse ratio and coefficient of variation, suggesting a presynaptic site of action. Uncoupling of postsynaptic G-proteins with intracellular GDP-β-S, or application of the nicotinic receptor antagonist, tubocurarine, failed to block the carbachol effect. In contrast, the carbachol effect was blocked by prior application of atropine or M(2) receptor-preferring antagonists, and was absent in M(2)/M(4) receptor knockout mice, suggesting that presynaptic M(2) receptors mediate the effect of ACh. Immunoelectron microscopy studies further revealed the presence of M(2) receptors on axon terminals that formed asymmetric synapses with BNST neurons. Our findings suggest that presynaptic M(2) receptors might be an important modulator of the stress circuit and hence a novel target for drug development.
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Affiliation(s)
- Ji-Dong Guo
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
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Emanuel AJ, Ritter S. Hindbrain catecholamine neurons modulate the growth hormone but not the feeding response to ghrelin. Endocrinology 2010; 151:3237-46. [PMID: 20463049 PMCID: PMC2903929 DOI: 10.1210/en.2010-0219] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The gastrointestinal peptide, ghrelin, elicits feeding and secretion when administered systemically or centrally. Previous studies have suggested that hypothalamic projections of hindbrain catecholamine neurons are involved in both of these actions of ghrelin. The purpose of this study was to further assess the role of hindbrain catecholamine neurons in ghrelin-induced feeding and GH secretion and to determine the anatomical distribution of the catecholamine neurons involved. We lesioned noradrenergic and adrenergic neurons that innervate the medial hypothalamus by microinjecting the retrogradely transported immunotoxin, saporin (SAP) conjugated to antidopamine-beta-hydroxylase (DSAP) into the paraventricular nucleus of the hypothalamus. Controls were injected with unconjugated SAP. We found that the DSAP lesion did not impair the feeding response to central or peripheral ghrelin administration, indicating that these neurons are not required for ghrelin's orexigenic effect. However, the GH response to ghrelin was prolonged significantly in DSAP-lesioned rats. We also found that expression of Fos, an indicator of neuronal activation, was significantly enhanced over baseline levels in A1, A1/C1, C1, and A5 cell groups after ghrelin treatment and in A1, A1/C1, and A5 cell groups after GH treatment. The similar pattern of Fos expression in catecholamine cell groups after GH and ghrelin and the prolonged GH secretion in response to ghrelin in DSAP rats together suggest that activation of hindbrain catecholamine neurons by ghrelin or GH could be a component of a negative feedback response controlling GH levels.
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Affiliation(s)
- Alan J Emanuel
- Programs in Neuroscience, Washington State University, Pullman, WA 99164-6520, USA
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Yellon SM, Grisham LA, Rambau GM, Lechuga TJ, Kirby MA. Pregnancy-related changes in connections from the cervix to forebrain and hypothalamus in mice. Reproduction 2010; 140:155-64. [PMID: 20453158 DOI: 10.1530/rep-10-0002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The transneuronal tracer pseudorabies virus was used to test the hypothesis that connections from the cervix to the forebrain and hypothalamus are maintained with pregnancy. The virus was injected into the cervix of nonpregnant or pregnant mice, and, after 5 days, virus-labeled cells and fibers were found in specific forebrain regions and, most prominently, in portions of the hypothalamic paraventricular nucleus. With pregnancy, fewer neurons and fibers were evident in most brain regions compared to that in nonpregnant mice. In particular, little or no virus was found in the medial and ventral parvocellular subdivisions, anteroventral periventricular nucleus, or motor cortex in pregnant mice. By contrast, labeling of virus was sustained in the dorsal hypothalamus and suprachiasmatic nucleus in all groups. Based upon image analysis of digitized photomicrographs, the area with label in the rostral and medial parvocellular paraventricular nucleus and magnocellular subdivisions was significantly reduced in mice whose cervix was injected with virus during pregnancy than in nonpregnant mice. The findings indicate that connections from the cervix to brain regions that are involved in sensory input and integrative autonomic functions are reduced during pregnancy. The findings raise the possibility that remaining pathways from the cervix to the forebrain and hypothalamus may be important for control of pituitary neuroendocrine secretion, as well as for effector functions in the cervix as pregnancy nears term.
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Affiliation(s)
- Steven M Yellon
- Departments of Physiology, Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, California 92354, USA.
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Kleiber AC, Zheng H, Sharma NM, Patel KP. Chronic AT1 receptor blockade normalizes NMDA-mediated changes in renal sympathetic nerve activity and NR1 expression within the PVN in rats with heart failure. Am J Physiol Heart Circ Physiol 2010; 298:H1546-55. [PMID: 20173042 DOI: 10.1152/ajpheart.01006.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exercise training normalizes enhanced glutamatergic mechanisms within the paraventricular nucleus (PVN) concomitant with the normalization of increased plasma ANG II levels in rats with heart failure (HF). We tested whether ANG II type 1 (AT(1)) receptors are involved in the normalization of PVN glutamatergic mechanisms using chronic AT(1) receptor blockade with losartan (Los; 50 mg.kg(-1).day(-1) in drinking water for 3 wk). Left ventricular end-diastolic pressure was increased in both HF + vehicle (Veh) and HF + Los groups compared with sham-operated animals (Sham group), although it was significantly attenuated in the HF + Los group compared with the HF + Veh group. The effect of Los on cardiac function was similar to exercise training. At the highest dose of N-methyl-d-aspartate (NMDA; 200 pmol) injected into the PVN, the increase in renal sympathetic nerve activity was 93 +/- 13% in the HF + Veh group, which was significantly higher (P < 0.05) than the increase in the Sham + Veh (45 +/- 2%) and HF + Los (47 +/- 2%) groups. Relative NMDA receptor subunit NR(1) mRNA expression within the PVN was increased 120% in the HF + Veh group compared with the Sham + Veh group (P < 0.05) but was significantly attenuated in the HF + Los group compared with the HF + Veh group (P < 0.05). NR(1) protein expression increased 87% in the HF + Veh group compared with the Sham + Veh group but was significantly attenuated in the HF + Los group compared with the HF + Veh group (P < 0.05). Furthermore, in in vitro experiments using neuronal NG-108 cells, we found that ANG II treatment stimulated NR(1) protein expression and that Los significantly ameliorated the NR(1) expression induced by ANG II. These data are consistent with our hypothesis that chronic AT(1) receptor blockade normalizes glutamatergic mechanisms within the PVN in rats with HF.
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Affiliation(s)
- Allison C Kleiber
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA
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36
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Nitric oxide and interleukin-1β mediate noradrenergic induced corticotrophin-releasing hormone release in organotypic cultures of rat paraventricular nucleus. Neuroscience 2010; 165:1191-202. [DOI: 10.1016/j.neuroscience.2009.12.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 11/27/2009] [Accepted: 12/01/2009] [Indexed: 11/18/2022]
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Simmons DM, Swanson LW. Comparison of the spatial distribution of seven types of neuroendocrine neurons in the rat paraventricular nucleus: toward a global 3D model. J Comp Neurol 2009; 516:423-41. [PMID: 19655400 DOI: 10.1002/cne.22126] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The paraventricular nucleus of the hypothalamus (PVH) coordinates neuroendocrine, autonomic, and behavioral responses to help maintain energy and body water balance. The rat paraventricular nucleus has three major divisions: descending with axonal projections to somatomotor-behavioral and autonomic circuitry, magnocellular neuroendocrine with projections directly to the posterior pituitary, and parvicellular neuroendocrine with projections to the median eminence for controlling anterior pituitary hormone secretion. The present work was undertaken to provide high-resolution mapping of spatial relationships among the two magnocellular neuroendocrine and five parvicellular neuroendocrine neuron types throughout the nucleus. Double immunohistochemical labeling for two neuron types combined with retrograde labeling to identify neuroendocrine neurons positively was used in individual sections spaced 45 mum apart, along with a grid transfer method for reducing plane of section artifacts when comparing staining pattern data between animals. The results indicate that whereas each neuroendocrine neuron phenotype displays a unique distribution pattern, there is extensive partial overlap in a complex pattern between small "hot spots" with a relatively high density of a particular neuron type and few if any other phenotypes. In addition, the distribution of non-neuroendocrine neurons staining with each of the markers (but not retrogradely labeled) was mapped and compared with each other and with the neuroendocrine neuron populations. This spatial organization raises important questions about the differential functional regulation of individual-and perhaps sets of-neuroendocrine motor neuron populations in the PVH by synaptic mechanisms and by less traditional mechanisms like dendritic neurotransmitter release and gap junctions within and between neuron types.
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Affiliation(s)
- Donna M Simmons
- Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-2520, USA
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38
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Denver RJ. Stress hormones mediate environment-genotype interactions during amphibian development. Gen Comp Endocrinol 2009; 164:20-31. [PMID: 19393659 DOI: 10.1016/j.ygcen.2009.04.016] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 04/13/2009] [Accepted: 04/17/2009] [Indexed: 12/31/2022]
Abstract
Environments experienced by organisms during early development shape the character and timing of developmental processes, leading to different probabilities of survival in the developmental habitat, and often profound effects on phenotypic expression later in life. Amphibian larvae have immense capacity for plasticity in behavior, morphology, growth and development rate. This creates the potential for extreme variation in the timing of, and size at metamorphosis, and subsequent phenotype in the juvenile and adult stage. Hormones of the neuroendocrine stress axis play pivotal roles in mediating environmental effects on animal development. Corticotropin-releasing factor, whose secretion by hypothalamic neurons is induced by environmental stress, influences the timing of amphibian metamorphosis by controlling the activity of the thyroid and interrenal (adrenal; corticosteroids) glands. At target tissues, corticosteroids synergize with thyroid hormone to promote metamorphosis. Thus, environmental stress acts centrally to increase the activity of the two principle endocrine axes controlling metamorphosis, and the effectors of these axes synergize at the level of target tissues to promote morphogenesis. While stress hormones can promote survival in a deteriorating larval habitat, costs may be incurred such as reduced tadpole growth and size at metamorphosis. Furthermore, exposure to elevated corticosteroids early in life can cause permanent changes in the expression of genes of the neuroendocrine stress axis, leading to altered physiology and behavior in the juvenile/adult stage. Persistent effects of stress hormone actions early in life may have important fitness consequences.
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Affiliation(s)
- Robert J Denver
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, 3065C Kraus Building, Ann Arbor, MI 48109-1048, USA.
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Jones AB, Curtis KS. Differential effects of estradiol on drinking by ovariectomized rats in response to hypertonic NaCl or isoproterenol: Implications for hyper- vs. hypo-osmotic stimuli for water intake. Physiol Behav 2009; 98:421-6. [PMID: 19616566 DOI: 10.1016/j.physbeh.2009.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/08/2009] [Accepted: 07/09/2009] [Indexed: 10/20/2022]
Abstract
We examined the effects of estradiol on behavioral responses to osmotic challenges in ovariectomized (OVX) rats to test the hypothesis that estradiol enhances sensitivity to gradual changes in plasma osmolality (pOsm) in stimulating water intake. Despite comparably elevated pOsm after a slow infusion of 2 M NaCl, the latency to begin water intake was significantly less in estradiol-treated OVX rats compared to that in oil vehicle-treated rats. Other groups of OVX rats were injected with isoproterenol, which increases circulating angiotensin II. These rats then were given 0.15 M NaCl to drink instead of water, to prevent decreased pOsm associated with water ingestion. Isoproterenol stimulated 0.15 M NaCl intake by both groups; however, estradiol-treated rats consumed less 0.15 M NaCl than did oil-treated rats, findings that are similar to those reported when estradiol-treated rats consumed water. The estradiol enhancement of sensitivity to increased, but not to decreased, pOsm suggests that estradiol has directionally-specific effects on osmoregulatory drinking. Moreover, the estradiol attenuation of 0.15 M NaCl intake after isoproterenol suggests that estradiol effects on osmoregulatory drinking are independent of those on volume regulatory drinking.
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Affiliation(s)
- Alexis B Jones
- Department of Pharmacology and Physiology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, USA
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Coleman CG, Anrather J, Iadecola C, Pickel VM. Angiotensin II type 2 receptors have a major somatodendritic distribution in vasopressin-containing neurons in the mouse hypothalamic paraventricular nucleus. Neuroscience 2009; 163:129-42. [PMID: 19539723 DOI: 10.1016/j.neuroscience.2009.06.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 05/21/2009] [Accepted: 06/12/2009] [Indexed: 01/16/2023]
Abstract
The hypothalamic paraventricular nucleus (PVN) and angiotensin II (AngII) play critical roles in cardiovascular and neurohumoral regulation ascribed in part to vasopressin (VP) release. The AngII actions in the PVN are mediated largely through angiotensin II type 1 (AT1) receptors. However, there is indirect evidence that the functionally elusive central angiotensin II type 2 (AT2) receptors are also mediators of AngII signaling in the PVN. We used electron microscopic dual immunolabeling of antisera recognizing the AT2 receptor and VP to test the hypothesis that mouse PVN neurons expressing VP are among the cellular sites where this receptor has a subcellular distribution conducive to local activation. Immunoreactivity for the AT2 receptor was detected in somatodendritic profiles, of which approximately 60% of the somata and approximately 28% of the dendrites also contained VP. In comparison with somata and dendrites, axons, axon terminals, and glia less frequently contained the AT2 receptor. Somatic labeling for the AT2 receptor was often seen in the cytoplasm near the Golgi lamellae and other endomembrane structures implicated in receptor trafficking. AT2 receptor immunoreactivity in dendrites was commonly localized to cytoplasmic endomembranes, but was occasionally observed on extra- or peri-synaptic portions of the plasma membrane apposed by astrocytic processes or by unlabeled axon terminals. The labeled dendritic plasmalemmal segments containing AT2 receptors received asymmetric excitatory-type or more rarely symmetric inhibitory-type contacts from unlabeled axon terminals containing dense core vesicles, many of which are known to store neuropeptides. These results provide the first ultrastructural evidence that AT2 receptors in PVN neurons expressing VP and other neuromodulators are strategically positioned for surface activation by AngII and/or intracellular trafficking.
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Affiliation(s)
- C G Coleman
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Medical College of Cornell University, 407 E 61st Street, New York, NY, USA.
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Westberg L, Sawa E, Wang AY, Gunaydin LA, Ribeiro AC, Pfaff DW. Colocalization of connexin 36 and corticotropin-releasing hormone in the mouse brain. BMC Neurosci 2009; 10:41. [PMID: 19405960 PMCID: PMC2688509 DOI: 10.1186/1471-2202-10-41] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 04/30/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Gap junction proteins, connexins, are expressed in most endocrine and exocrine glands in the body and are at least in some glands crucial for the hormonal secretion. To what extent connexins are expressed in neurons releasing hormones or neuropeptides from or within the central nervous system is, however, unknown. Previous studies provide indirect evidence for gap junction coupling between subsets of neuropeptide-containing neurons in the paraventricular nucleus (PVN) of the hypothalamus. Here we employ double labeling and retrograde tracing methods to investigate to what extent neuroendocrine and neuropeptide-containing neurons of the hypothalamus and brainstem express the neuronal gap junction protein connexin 36. RESULTS Western blot analysis showed that connexin 36 is expressed in the PVN. In bacterial artificial chromosome transgenic mice, which specifically express the reporter gene Enhanced Green Fluorescent Protein (EGFP) under the control of the connexin 36 gene promoter, EGFP expression was detected in magnocellular (neuroendocrine) and in parvocellular neurons of the PVN. Although no EGFP/connexin36 expression was seen in neurons containing oxytocin or vasopressin, EGFP/connexin36 was found in subsets of PVN neurons containing corticotropin-releasing hormone (CRH), and in somatostatin neurons located along the third ventricle. Moreover, CRH neurons in brainstem areas, including the lateral parabrachial nucleus, also expressed EGFP/connexin 36. CONCLUSION Our data indicate that connexin 36 is expressed in subsets of neuroendocrine and CRH neurons in specific nuclei of the hypothalamus and brainstem.
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Affiliation(s)
- Lars Westberg
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Evelyn Sawa
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Alice Y Wang
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Lisa A Gunaydin
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Ana C Ribeiro
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
| | - Donald W Pfaff
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, NY10021, New York, USA
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42
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Denver RJ. Structural and Functional Evolution of Vertebrate Neuroendocrine Stress Systems. Ann N Y Acad Sci 2009; 1163:1-16. [DOI: 10.1111/j.1749-6632.2009.04433.x] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bora A, Annangudi SP, Millet LJ, Rubakhin SS, Forbes AJ, Kelleher NL, Gillette MU, Sweedler JV. Neuropeptidomics of the supraoptic rat nucleus. J Proteome Res 2008; 7:4992-5003. [PMID: 18816085 PMCID: PMC2646869 DOI: 10.1021/pr800394e] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mammalian supraoptic nucleus (SON) is a neuroendocrine center in the brain regulating a variety of physiological functions. Within the SON, peptidergic magnocellular neurons that project to the neurohypophysis (posterior pituitary) are involved in controlling osmotic balance, lactation, and parturition, partly through secretion of signaling peptides such as oxytocin and vasopressin into the blood. An improved understanding of SON activity and function requires identification and characterization of the peptides used by the SON. Here, small-volume sample preparation approaches are optimized for neuropeptidomic studies of isolated SON samples ranging from entire nuclei down to single magnocellular neurons. Unlike most previous mammalian peptidome studies, tissues are not immediately heated or microwaved. SON samples are obtained from ex vivo brain slice preparations via tissue punch and the samples processed through sequential steps of peptide extraction. Analyses of the samples via liquid chromatography mass spectrometry and tandem mass spectrometry result in the identification of 85 peptides, including 20 unique peptides from known prohormones. As the sample size is further reduced, the depth of peptide coverage decreases; however, even from individually isolated magnocellular neuroendocrine cells, vasopressin and several other peptides are detected.
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Affiliation(s)
- Adriana Bora
- Neuroscience Program, Department of Cell and Developmental Biology, Beckman Institute, and Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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44
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Chen H, Hansen MJ, Jones JE, Vlahos R, Anderson GP, Morris MJ. Long-term cigarette smoke exposure increases uncoupling protein expression but reduces energy intake. Brain Res 2008; 1228:81-8. [PMID: 18619427 DOI: 10.1016/j.brainres.2008.06.067] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 06/17/2008] [Accepted: 06/19/2008] [Indexed: 11/24/2022]
Abstract
The appetite suppressing effect of tobacco is a major driver of smoking behaviour; however few studies have addressed the effects of chronic cigarette smoke exposure (SE) on appetite, body weight and metabolic markers. We compared the effects of SE to equivalent food restriction (pair-fed, PF), against sham-exposure, on body weight, adiposity, cytokines, and levels of uncoupling proteins (UCP) and brain neuropeptide Y (NPY) in male Balb/C mice. SE rapidly induced anorexia, and after 12 weeks, SE and PF groups were lighter than control animals (23.9+/-0.2, 25.5+/-0.5, 26.8+/-0.4 g respectively, P<0.05). White fat (WAT) masses were reduced by both SE and PF. Plasma leptin and insulin were reduced in SE mice; insulin was further reduced by PF. Brown fat UCP1 and 3 mRNA were increased in SE animals relative to PF animals, possibly promoting thermogenesis. WAT mRNA expression of the inflammatory cytokine, TNFalpha was doubled by SE, while IL-6 was reduced by both PF and SE. Hypothalamic NPY content was increased by SE (89.3+/-2.8 vs. 75.9+/-2.4 ng control, P<0.05), and more by PF (100.7+/-3.4 ng, P<0.05 compared to both groups), suggesting disinhibition due to reduced adipose derived leptin. In contrast to equivalent food restriction, cigarette smoke exposure reduced body weight and total hypothalamic NPY, and increased thermogenesis and markers of inflammation. The suppressed hypothalamic NPY and increased UCPs may contribute to the spontaneous hypophagia and extra weight loss in SE animals. These findings contribute to our understanding of weight loss in smoking-related lung disease, suggesting a greater impact than that due to anorexia alone.
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Affiliation(s)
- Hui Chen
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, NSW 2052, Australia
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Jia R, Tai F, An S, Broders H, Ding X, Kong Q, Zhao L, Zhang H. Effects of neonatal oxytocin treatment on aggression and neural activities in mandarin voles. Physiol Behav 2008; 95:56-62. [DOI: 10.1016/j.physbeh.2008.04.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 04/04/2008] [Accepted: 04/09/2008] [Indexed: 11/25/2022]
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Vertes RP, Hoover WB. Projections of the paraventricular and paratenial nuclei of the dorsal midline thalamus in the rat. J Comp Neurol 2008; 508:212-37. [PMID: 18311787 DOI: 10.1002/cne.21679] [Citation(s) in RCA: 210] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The paraventricular (PV) and paratenial (PT) nuclei are prominent cell groups of the midline thalamus. To our knowledge, only a single early report has examined PV projections and no previous study has comprehensively analyzed PT projections. By using the anterograde anatomical tracer, Phaseolus vulgaris leucoagglutinin, and the retrograde tracer, FluoroGold, we examined the efferent projections of PV and PT. We showed that the output of PV is virtually directed to a discrete set of limbic forebrain structures, including 'limbic' regions of the cortex. These include the infralimbic, prelimbic, dorsal agranular insular, and entorhinal cortices, the ventral subiculum of the hippocampus, dorsal tenia tecta, claustrum, lateral septum, dorsal striatum, nucleus accumbens (core and shell), olfactory tubercle, bed nucleus of stria terminalis (BST), medial, central, cortical, and basal nuclei of amygdala, and the suprachiasmatic, arcuate, and dorsomedial nuclei of the hypothalamus. The posterior PV distributes more heavily than the anterior PV to the dorsal striatum and to the central and basal nuclei of amygdala. PT projections significantly overlap with those of PV, with some important differences. PT distributes less heavily than PV to BST and to the amygdala, but much more densely to the medial prefrontal and entorhinal cortices and to the ventral subiculum of hippocampus. As described herein, PV/PT receive a vast array of afferents from the brainstem, hypothalamus, and limbic forebrain, related to arousal and attentive states of the animal, and would appear to channel that information to structures of the limbic forebrain in the selection of appropriate responses to changing environmental conditions. Depending on the specific complement of emotionally associated information reaching PV/PT at any one time, PV/PT would appear positioned, by actions on the limbic forebrain, to direct behavior toward a particular outcome over a range of outcomes.
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Affiliation(s)
- Robert P Vertes
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida 33431, USA.
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Yao M, Schulkin J, Denver RJ. Evolutionarily conserved glucocorticoid regulation of corticotropin-releasing factor expression. Endocrinology 2008; 149:2352-60. [PMID: 18202128 DOI: 10.1210/en.2007-1551] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glucocorticoids (GCs) exert feedback regulation on corticotropin-releasing factor (CRF) neurons in mammals. The nature of GC actions is cell-type specific, being either inhibitory (e.g. paraventricular nucleus) or stimulatory (e.g. amygdala and bed nucleus of the stria terminalis). Nothing is known about differential regulation of CRF gene expression by GCs in nonmammalian vertebrates. We studied the actions of GCs on CRF expression in discrete brain regions of the frog Xenopus laevis. Treatment with corticosterone (CORT) decreased, whereas the corticosteroid synthesis inhibitor metyrapone increased CRF expression in the anterior preoptic area (homolog of the mammalian paraventricular nucleus), as measured by CRF primary transcript, mRNA, and CRF immunoreactivity (ir) (by immunocytochemistry). By contrast to the preoptic area, CORT increased CRF-ir in the medial amygdala and bed nucleus of the stria terminalis, whereas metyrapone decreased CRF-ir in the medial amygdala. CRF-ir and glucocorticoid receptor-ir were colocalized in cells in the frog brain. In transient transfection assays in PC-12 cells, GCs decreased forskolin-induced activation of the frog CRF promoters. Treatment with CORT also reduced CRF promoter activity in transfected tadpole brain in vivo. Frog glucocorticoid receptor bound with high-affinity in vitro to regions in the proximal promoters of frog CRF genes that are homologous with the human CRF gene. Our findings suggest that the neural cell-type specificity and molecular mechanisms of GC-dependent regulation of CRF are phylogenetically ancient, and that the limbic pathways mediating behavioral and physiological responses to stressors were likely present in the earliest land-dwelling vertebrates.
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Affiliation(s)
- Meng Yao
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, 830 North University Avenue, Ann Arbor, Michigan 48109-1048, USA
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Simmons DM, Swanson LW. High-resolution paraventricular nucleus serial section model constructed within a traditional rat brain atlas. Neurosci Lett 2008; 438:85-9. [PMID: 18479821 DOI: 10.1016/j.neulet.2008.04.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 04/04/2008] [Accepted: 04/07/2008] [Indexed: 12/17/2022]
Abstract
As a starting point for constructing a high-resolution, resliceable computer graphics model for the extraction, quantitative analysis, display, and modeling of neuroanatomical data the outer border and the boundaries of inner divisions and parts of the paraventricular nucleus have been drawn for all 39 serial histological sections prepared for a published reference atlas of the rat brain. This careful parceling revealed three new features of paraventricular nucleus topography: the full rostral extent of the anterior parvicellular part, the caudal end of the medial magnocellular part, and a thin rostrolateral extension of the dorsal medial parvicellular part composed at least in part of neurons expressing corticotropin-releasing hormone. The vector graphics drawings were aligned using the already established alignment of nine consecutive, relevant Atlas Levels, and then contours were smoothed to eliminate nonlinear distortions associated with histological mounting. This dataset was then used to create three-dimensional contour and surface models of the paraventricular nucleus, as well as two-dimensional horizontal and sagittal projections of its outer border. The computer graphics files containing raw and smoothed drawings for all 39 serial sections are supplied for use by researchers interested in developing new or better computer graphics analysis tools involving the paraventricular nucleus. This work may also stimulate the long range goal of creating a high-resolution, resliceable, computer graphics model of the whole brain, and eventually the whole nervous system, that is useful for quantitative analysis and topological transformation.
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Affiliation(s)
- Donna M Simmons
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2520, USA
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López M, Tovar S, Vázquez MJ, Williams LM, Diéguez C. Peripheral tissue-brain interactions in the regulation of food intake. Proc Nutr Soc 2007; 66:131-55. [PMID: 17343779 DOI: 10.1017/s0029665107005368] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
More than 70 years ago the glucostatic, lipostatic and aminostatic hypotheses proposed that the central nervous system sensed circulating levels of different metabolites, changing feeding behaviour in response to the levels of those molecules. In the last 20 years the rapid increase in obesity and associated pathologies in developed countries has involved a substantial increase in the knowledge of the physiological and molecular mechanism regulating body mass. This effort has resulted in the recent discovery of new peripheral signals, such as leptin and ghrelin, as well as new neuropeptides, such as orexins, involved in body-weight homeostasis. The present review summarises research into energy balance, starting from the original classical hypotheses proposing metabolite sensing, through peripheral tissue-brain interactions and coming full circle to the recently-discovered role of hypothalamic fatty acid synthase in feeding regulation. Understanding these molecular mechanisms will provide new pharmacological targets for the treatment of obesity and appetite disorders.
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Affiliation(s)
- Miguel López
- Department of Physiology, School of Medicine, University of Santiago de Compostela, C/San Francisco s/n 15782, Santiago de Compostela, A Coruña, Spain
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Abstract
Rapid changes of state in central nervous systems (CNS), as required following stimuli that must arouse the CNS from a quiescent state in order to activate a behavioral response, constitute a particularly appropriate application of non-linear dynamics. Chaotic dynamics would provide tremendous amplification of neuronal activity needed for CNS arousal, sensitively dependent on the initial state of the CNS. This theoretical approach is attractive because it supposes dynamics that are deterministic and it links the elegant mathematics of chaos to the conception of a fundamental property of the CNS. However, a living system must be able to exit from chaotic dynamics in order to avoid widely divergent, biologically impossible outcomes. We hypothesize that, analogous to phase transitions in a liquid crystal, CNS arousal systems, having 'woken up the brain' to activate behavior, go through a phase transition and emerge under the control of orderly movement control systems.
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Affiliation(s)
- Donald Pfaff
- Department of Physics, The Pennsylvania State University, University Park, PA, USA.
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