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Xia M, Wang T, Wang Y, Hu T, Chen D, Wang B. A neural perspective on the treatment of hypertension: the neurological network excitation and inhibition (E/I) imbalance in hypertension. Front Cardiovasc Med 2024; 11:1436059. [PMID: 39323755 PMCID: PMC11422145 DOI: 10.3389/fcvm.2024.1436059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 08/29/2024] [Indexed: 09/27/2024] Open
Abstract
Despite the increasing number of anti-hypertensive drugs have been developed and used in the clinical setting, persistent deficiencies persist, including issues such as lifelong dosage, combination therapy. Notwithstanding receiving the treatment under enduring these deficiencies, approximately 4 in 5 patients still fail to achieve reliable blood pressure (BP) control. The application of neuromodulation in the context of hypertension presents a pioneering strategy for addressing this condition, con-currently implying a potential central nervous mechanism underlying hypertension onset. We hypothesize that neurological networks, an essential component of maintaining appropriate neurological function, are involved in hypertension. Drawing on both peer-reviewed research and our laboratory investigations, we endeavor to investigate the underlying neural mechanisms involved in hypertension by identifying a close relationship between its onset of hypertension and an excitation and inhibition (E/I) imbalance. In addition to the involvement of excitatory glutamatergic and GABAergic inhibitory system, the pathogenesis of hypertension is also associated with Voltage-gated sodium channels (VGSCs, Nav)-mediated E/I balance. The overloading of glutamate or enhancement of glutamate receptors may be attributed to the E/I imbalance, ultimately triggering hypertension. GABA loss and GABA receptor dysfunction have also proven to be involved. Furthermore, we have identified that abnormalities in sodium channel expression and function alter neural excitability, thereby disturbing E/I balance and potentially serving as a mechanism underlying hypertension. These insights are expected to furnish potential strategies for the advancement of innovative anti-hypertensive therapies and a meaningful reference for the exploration of central nervous system (CNS) targets of anti-hypertensives.
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Affiliation(s)
- Min Xia
- Department of Anesthesiology, General Hospital of The Yangtze River Shipping, Wuhan Brain Hospital, Wuhan, China
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
| | - Tianyu Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
| | - Yizhu Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
- College of Pharmacy, Dalian Medical University, Dalian, China
| | - Tingting Hu
- Department of Anesthesiology, General Hospital of The Yangtze River Shipping, Wuhan Brain Hospital, Wuhan, China
| | - Defang Chen
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
- Emergency Intensive Care Unit, Qingpu Branch of Zhongshan Hospital, Fudan University, Shanghai, China
| | - Bin Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
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Li L, Su Y, Wang S, Wang C, Ruan N, Hu Z, Cheng X, Chen J, Yuan K, Li P, Fan P. Neonatal di-(2-ethylhexyl)phthalate exposure induces permanent alterations in secretory CRH neuron characteristics in the hypothalamus paraventricular region of adult male rats. Exp Neurol 2024; 372:114616. [PMID: 38007208 DOI: 10.1016/j.expneurol.2023.114616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/31/2023] [Accepted: 11/19/2023] [Indexed: 11/27/2023]
Abstract
Corticotrophin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus (PVN) play a critical role in the modulation of the hypothalamic-pituitary-adrenal (HPA) axis. Early-life exposure to di-(2-ethylhexyl) phthalate (DEHP) has been associated with an increased risk of developing psychiatric disorders in adulthood. The present work was designed to explore the impact of neonatal exposure to DEHP on adult PVN CRH neuronal activity. DEHP or vehicle was given to male rat pups from PND16 to PND22. Then, anxiety-like behaviors, serum corticosterone and testosterone, immunohistochemistry, western blotting, fluorescence in situ hybridization and acute ex vivo slice electrophysiological recordings were used to evaluate the influence of DEHP on adult PVN secretory CRH neurons. Neonatal DEHP-exposed rats exhibited enhanced anxiety-like behaviors in adults, with an increase in CORT. Secretory CRH neurons showed higher spontaneous firing activity but could be inhibited by GABAAR blockers. CRH neurons displayed fewer firing spikes, prolonged first-spike latency, depolarizing shifts in GABA reversal potential and strengthened GABAergic inputs, as indicated by increases in the frequency and amplitude of sIPSCs. Enhancement of GABAergic transmission was accompanied by upregulated expression of GAD67 and downregulated expression of GABABR1, KCC2 and GAT1. These findings suggest that neonatal exposure to DEHP permanently altered the characteristics of secretory CRH neurons in the PVN, which may contribute to the development of psychiatric disorders later in life.
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Affiliation(s)
- Li Li
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Ying Su
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Siyuan Wang
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China; Brain Injury Center, Department of Neurosurgery, RenJi Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai 200127, China
| | - Chengyu Wang
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Naqi Ruan
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Zhiyan Hu
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Xin Cheng
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Jiajia Chen
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Kaiming Yuan
- Key Laboratory of Anesthesiology of Zhejiang Province, Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China.
| | - Peijun Li
- Department of Neurology, Institute of Geriatric Neurology, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China.
| | - Pei Fan
- Zhejiang Provincial Key Laboratory of Orthopedics, Department of Orthopedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China.
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McArdle CJ, Arnone AA, Heaney CF, Raab-Graham KF. A paradoxical switch: the implications of excitatory GABAergic signaling in neurological disorders. Front Psychiatry 2024; 14:1296527. [PMID: 38268565 PMCID: PMC10805837 DOI: 10.3389/fpsyt.2023.1296527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024] Open
Abstract
Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. In the mature brain, inhibitory GABAergic signaling is critical in maintaining neuronal homeostasis and vital human behaviors such as cognition, emotion, and motivation. While classically known to inhibit neuronal function under physiological conditions, previous research indicates a paradoxical switch from inhibitory to excitatory GABAergic signaling that is implicated in several neurological disorders. Various mechanisms have been proposed to contribute to the excitatory switch such as chloride ion dyshomeostasis, alterations in inhibitory receptor expression, and modifications in GABAergic synaptic plasticity. Of note, the hypothesized mechanisms underlying excitatory GABAergic signaling are highlighted in a number of neurodevelopmental, substance use, stress, and neurodegenerative disorders. Herein, we present an updated review discussing the presence of excitatory GABAergic signaling in various neurological disorders, and their potential contributions towards disease pathology.
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Affiliation(s)
- Colin J. McArdle
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Alana A. Arnone
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
- Department of General Surgery, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Chelcie F. Heaney
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Kimberly F. Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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Nguyen DH, Duque V, Phillips N, Mecawi AS, Cunningham JT. Spatial transcriptomics reveal basal sex differences in supraoptic nucleus gene expression of adult rats related to cell signaling and ribosomal pathways. Biol Sex Differ 2023; 14:71. [PMID: 37858270 PMCID: PMC10585758 DOI: 10.1186/s13293-023-00554-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND The supraoptic nucleus (SON) of the hypothalamus contains magnocellular neurosecretory cells that secrete the hormones vasopressin and oxytocin. Sex differences in SON gene expression have been relatively unexplored. Our study used spatially resolved transcriptomics to visualize gene expression profiles in the SON of adult male (n = 4) and female (n = 4) Sprague-Dawley rats using Visium Spatial Gene Expression (10x Genomics). METHODS Briefly, 10-μm coronal sections (~ 4 × 4 mm) containing the SON were collected from each rat and processed using Visium slides and recommended protocols. Data were analyzed using 10x Genomics' Space Ranger and Loupe Browser applications and other bioinformatic tools. Two unique differential expression (DE) analysis methods, Loupe Browser and DESeq2, were used. RESULTS Loupe Browser DE analysis of the SON identified 116 significant differentially expressed genes (DEGs) common to both sexes (e.g., Avp and Oxt), 31 significant DEGs unique to the males, and 73 significant DEGs unique to the females. DESeq2 analysis revealed 183 significant DEGs between the two groups. Gene Ontology (GO) enrichment and pathway analyses using significant genes identified via Loupe Browser revealed GO terms and pathways related to (1) neurohypophyseal hormone activity, regulation of peptide hormone secretion, and regulation of ion transport for the significant genes common to both males and females, (2) Gi signaling/G-protein mediated events for the significant genes unique to males, and (3) potassium ion transport/voltage-gated potassium channels for the significant genes unique to females, as some examples. GO/pathway analyses using significant genes identified via DESeq2 comparing female vs. male groups revealed GO terms/pathways related to ribosomal structure/function. Ingenuity Pathway Analysis (IPA) identified additional sex differences in canonical pathways (e.g., 'Mitochondrial Dysfunction', 'Oxidative Phosphorylation') and upstream regulators (e.g., CSF3, NFKB complex, TNF, GRIN3A). CONCLUSION There was little overlap in the IPA results for the two different DE methods. These results suggest sex differences in SON gene expression that are associated with cell signaling and ribosomal pathways.
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Affiliation(s)
- Dianna H Nguyen
- Department of Physiology and Anatomy, School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX, USA
- Texas College of Osteopathic Medicine, UNT Health Science Center, Fort Worth, TX, USA
| | - Victor Duque
- Department of Biophysics, Laboratory of Molecular Neuroendocrinology, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Nicole Phillips
- Department of Microbiology, Immunology, and Genetics, School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX, USA
| | - André Souza Mecawi
- Department of Biophysics, Laboratory of Molecular Neuroendocrinology, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - J Thomas Cunningham
- Department of Physiology and Anatomy, School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX, USA.
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Aikins AO, Farmer GE, Little JT, Cunningham JT. Effects of bile duct ligation on the inhibitory control of supraoptic vasopressin neurons. J Neuroendocrinol 2023; 35:e13312. [PMID: 37337093 PMCID: PMC10942741 DOI: 10.1111/jne.13312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/02/2023] [Accepted: 05/11/2023] [Indexed: 06/21/2023]
Abstract
Dilutional hyponatremia due to increased plasma arginine vasopressin (AVP) is associated with liver cirrhosis. However, plasma AVP remains elevated despite progressive hypoosmolality. This study investigated changes to inhibitory control of supraoptic nucleus (SON) AVP neurons during liver cirrhosis. Experiments were conducted with adult male Sprague-Dawley rats. Bile duct ligation was used as a model of chronic liver cirrhosis. An adeno-associated virus containing a construct with an AVP promoter and either green fluorescent protein (GFP) or a ratiometric chloride indicator, ClopHensorN, was bilaterally injected into the SON of rats. After 2 weeks, rats received either BDL or sham surgery, and liver cirrhosis was allowed to develop for 4 weeks. In vitro, loose patch recordings of action potentials were obtained from GFP-labeled and unlabeled SON neurons in response to a brief focal application of the GABAA agonist muscimol (100 μM). Changes to intracellular chloride ([Cl]i) following muscimol application were determined by changes to the fluorescence ratio of ClopHensorN. The contribution of cation chloride cotransporters NKCC1 and KCC2 to changes in intracellular chloride was investigated using their respective antagonists, bumetanide (BU, 10 μM) and VU0240551 (10 μM). Plasma osmolality and hematocrit were measured as a marker of dilutional hyponatremia. The results showed reduced or absent GABAA -mediated inhibition in a greater proportion of AVP neurons from BDL rats as compared to sham rats (100% inhibition in sham vs. 47% in BDL, p = .001). Muscimol application was associated with increased [Cl]i in most cells from BDL as compared to cells from sham rats (χ2 = 30.24, p < .001). NKCC1 contributed to the impaired inhibition observed in BDL rats (p < .001 BDL - BU vs. BDL + BU). The results show that impaired inhibition of SON AVP neurons and increased intracellular chloride contribute to the sustained dilutional hyponatremia in liver cirrhosis.
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Affiliation(s)
- Ato O Aikins
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - George E Farmer
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Joel T Little
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - J Thomas Cunningham
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Gomes PM, Batista JS, Sá RWM, Antunes VR. Short exposure to high salt in drinking solution leads to a cardiovascular phenotype of hypertension without changes in the blood volume of rats. Exp Physiol 2023; 108:361-370. [PMID: 36715005 PMCID: PMC10103861 DOI: 10.1113/ep090912] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 01/06/2023] [Indexed: 01/31/2023]
Abstract
NEW FINDINGS What is the central question of this study? Is the cardiovascular phenotype of high blood pressure observed in rats salt loaded with 2% NaCl in drinking solution a blood volume-dependent hypertension? What is the main finding and its importance? Animals exposed to 2% NaCl drinking solution develop hypertension, with dominance of sympathetic outflow and high [Na+ ] in the cerebrospinal fluid, but without changes in the blood volume. The phenotype of salt-dependent hypertension might be related to accumulation of [Na+ ] in the cerebrospinal fluid, which makes it an interesting animal model in which to study the neuronal pathways involved in control of the circulation in osmotic challenge conditions. ABSTRACT Evidence suggests that hypertension induced by high salt intake is correlated with an autonomic imbalance that favours sympathetic hyperactivity and an increase in vascular resistance, indicating a neurogenic component to this pathology. Although there are several animal models in which to study salt-induced hypertension with prolonged exposure to a high-sodium diet, here we sought to investigate whether the increase in arterial blood pressure of rats subjected to a short exposure to high salt, with 2% NaCl drinking solution instead of water, relies on changes in the circulating blood volume. Male Wistar rats were divided randomly into three groups: euhydrated (EU, n = 10), salt loaded (SL, n = 13) and water deprived (WD, n = 6). The SL rats exhibited a significant increase in mean arterial blood pressure, with a large low-frequency component of systolic arterial blood pressure variability, when compared with the EU group. Circulating blood volume did not differ between SL and EU rats, but it was lower in WD rats. Compared with EU rats, the [Na+ ] in cerebrospinal fluid was higher in SL rats and similar in magnitude to the WD rats. Plasma [Na+ ] did not differ between SL and EU rats, but it was higher in WD rats. Collectively, our data suggest that the hypertension induced by a short exposure to high salt intake closely resembles a neurogenic mechanism, but not a blood volume-dependent mechanism, with cumulative [Na+ ] in the cerebrospinal fluid that could be associated with changes in the neurochemistry of autonomic nuclei, which are highly susceptible to osmotic stress related to high salt consumption.
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Affiliation(s)
- Paula Magalhães Gomes
- Department of Physiology and BiophysicsInstitute of Biomedical SciencesUniversity of Sao PauloSao PauloSPBrazil
| | - Julia Santos Batista
- Department of Physiology and BiophysicsInstitute of Biomedical SciencesUniversity of Sao PauloSao PauloSPBrazil
| | - Renato Willian Martins Sá
- Department of Physiology and BiophysicsInstitute of Biomedical SciencesUniversity of Sao PauloSao PauloSPBrazil
| | - Vagner Roberto Antunes
- Department of Physiology and BiophysicsInstitute of Biomedical SciencesUniversity of Sao PauloSao PauloSPBrazil
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Bárez-López S, Scanlon L, Murphy D, Greenwood MP. Imaging the Hypothalamo-Neurohypophysial System. Neuroendocrinology 2023; 113:168-178. [PMID: 34438401 DOI: 10.1159/000519233] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/23/2021] [Indexed: 11/19/2022]
Abstract
The hypothalamo-neurohypophysial system (HNS) is a brain peptidergic neurosecretory apparatus which is composed of arginine vasopressin (AVP) and oxytocin (OXT) magnocellular neurones and their neuronal processes in the posterior pituitary (PP). In response to specific stimuli, AVP and OXT are secreted into the systemic circulation at the neurovascular interface of the PP, where they act as hormones, but they can also behave as neurotransmitters when released at the somatodendritic compartment or by axon collaterals to other brain regions. Because these peptides are crucial for several physiological processes, including fluid homoeostasis and reproduction, it is of great importance to map the HNS connectome in its entirety in order to understand its functions. In recent years, advances in imaging technologies have provided considerable new information about the HNS. These approaches include the use of reporter proteins under the control of specific promoters, viral tracers, brain-clearing methods, genetically encoded indicators, sniffer cells, mass spectrometry imaging, and spatially resolved transcriptomics. In this review, we illustrate how these latest approaches have enhanced our understanding of the structure and function of the HNS and how they might contribute further in the coming years.
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Affiliation(s)
- Soledad Bárez-López
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Liam Scanlon
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - David Murphy
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Michael Paul Greenwood
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
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Masuda T, Ohara K, Vallon V, Nagata D. SGLT2 inhibitor and loop diuretic induce different vasopressin and fluid homeostatic responses in nondiabetic rats. Am J Physiol Renal Physiol 2022; 323:F361-F369. [PMID: 35900341 PMCID: PMC9423725 DOI: 10.1152/ajprenal.00070.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 12/12/2022] Open
Abstract
Loop diuretics are commonly used diuretics in the treatment of fluid retention but induce hypovolemia-related renal dysfunction. Na+-glucose cotransporter 2 (SGLT2) inhibitors induce osmotic diuresis, but body fluid volume is maintained by stimulating vasopressin-induced fluid intake and collecting duct water reabsorption as previously reported in diabetic rats. We aimed to test the hypothesis that unlike SGLT2 inhibitors, loop diuretics lack activation of similar fluid homeostatic mechanisms. Nondiabetic male Sprague-Dawley rats were treated daily by oral gavage with vehicle, the SGLT2 inhibitor ipragliflozin (5 mg/kg), or the loop diuretic furosemide (50 mg/kg) and monitored in metabolic cages for 2 or 7 days. Ipragliflozin and furosemide similarly increased urine volume on day 2. This was associated with increased serum Na+ concentration, urine vasopressin excretion, fluid intake, and solute-free water reabsorption in response to ipragliflozin but not to furosemide. Ipragliflozin maintained fluid balance (fluid intake - urine volume) on day 2 and total body water measured by bioimpedance spectroscopy and serum creatinine on day 7. In comparison, furosemide decreased fluid balance on day 2 and decreased total body water and increased serum creatinine on day 7. Furosemide, but not ipragliflozin, increased plasma renin activity, and systolic blood pressure was similar among the groups. In conclusion, the osmotic diuresis of the SGLT2 inhibitor increased serum Na+ concentration and the vasopressin-related stimulation of fluid intake and renal water retention maintained fluid balance, whereas the loop diuretic did not engage the compensatory vasopressin system. The data suggest differences in vasopressin and fluid homeostatic responses between SGLT2 inhibitors and loop diuretics.NEW & NOTEWORTHY In nondiabetic rats, the Na+-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin increased vasopressin-related stimulation of fluid intake and free water reabsorption and maintained fluid balance and serum creatinine, whereas the loop diuretic furosemide reduced vasopressin and induced a negative fluid balance followed by a subsequent increase in serum creatinine. This study suggests that differences in vasopressin secretion in response to a SGLT2 inhibitor or loop diuretic may contribute to differences in body fluid status and subsequent renal function.
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Affiliation(s)
- Takahiro Masuda
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Ken Ohara
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Volker Vallon
- Division of Nephrology and Hypertension, Departments of Medicine and Pharmacology, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Daisuke Nagata
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
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Fernandes ACA, de Oliveira FP, Fernandez G, da Guia Vieira L, Rosa CG, do Nascimento T, de Castro França S, Donato J, Vella KR, Antunes-Rodrigues J, Mecawi AS, Perello M, Elias LLK, Rorato R. Arcuate AgRP, but not POMC neurons, modulate paraventricular CRF synthesis and release in response to fasting. Cell Biosci 2022; 12:118. [PMID: 35902915 PMCID: PMC9331576 DOI: 10.1186/s13578-022-00853-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/14/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The activation of the hypothalamic-pituitary-adrenal (HPA) axis is essential for metabolic adaptation in response to fasting. However, the neurocircuitry connecting changes in the peripheral energy stores to the activity of hypothalamic paraventricular corticotrophin-releasing factor (CRFPVN) neurons, the master controller of the HPA axis activity, is not completely understood. Our main goal was to determine if hypothalamic arcuate nucleus (ARC) POMC and AgRP neurons can communicate fasting-induced changes in peripheral energy stores, associated to a fall in plasma leptin levels, to CRFPVN neurons to modulate the HPA axis activity in mice. RESULTS We observed increased plasma corticosterone levels associate with increased CRFPVN mRNA expression and increased CRFPVN neuronal activity in 36 h fasted mice. These responses were associated with a fall in plasma leptin levels and changes in the mRNA expression of Agrp and Pomc in the ARC. Fasting-induced decrease in plasma leptin partially modulated these responses through a change in the activity of ARC neurons. The chemogenetic activation of POMCARC by DREADDs did not affect fasting-induced activation of the HPA axis. DREADDs inhibition of AgRPARC neurons reduced the content of CRFPVN and increased its accumulation in the median eminence but had no effect on corticosterone secretion induced by fasting. CONCLUSION Our data indicate that AgRPARC neurons are part of the neurocircuitry involved in the coupling of PVNCRF activity to changes in peripheral energy stores induced by prolonged fasting.
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Affiliation(s)
| | - Franciane Pereira de Oliveira
- Department of Biophysics, Paulista Medical School, Federal University of Sao Paulo, São Paulo, SP, CEP 04023-062, Brazil
| | - Gimena Fernandez
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata, La Plata, 403, Buenos Aires, Argentina
| | - Luane da Guia Vieira
- Department of Biotechnology, University of Ribeirao Preto, Ribeirão Prêto, SP, 14096-900, Brazil
| | - Cristiane Gugelmin Rosa
- Department of Biotechnology, University of Ribeirao Preto, Ribeirão Prêto, SP, 14096-900, Brazil
| | - Taís do Nascimento
- Department of Biotechnology, University of Ribeirao Preto, Ribeirão Prêto, SP, 14096-900, Brazil
| | - Suzelei de Castro França
- Department of Biotechnology, University of Ribeirao Preto, Ribeirão Prêto, SP, 14096-900, Brazil
| | - Jose Donato
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil
| | - Kristen R Vella
- Department of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medical College, New York, NY, 10021, USA
| | - Jose Antunes-Rodrigues
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirão Prêto, SP, 14049-900, Brazil
| | - André Souza Mecawi
- Department of Biophysics, Paulista Medical School, Federal University of Sao Paulo, São Paulo, SP, CEP 04023-062, Brazil
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata, La Plata, 403, Buenos Aires, Argentina
| | - Lucila Leico Kagohara Elias
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirão Prêto, SP, 14049-900, Brazil
| | - Rodrigo Rorato
- Department of Biotechnology, University of Ribeirao Preto, Ribeirão Prêto, SP, 14096-900, Brazil. .,Department of Biophysics, Paulista Medical School, Federal University of Sao Paulo, São Paulo, SP, CEP 04023-062, Brazil.
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10
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Orikasa C. Social Network Plasticity of Mice Parental Behavior. Front Neurosci 2022; 16:882850. [PMID: 35747212 PMCID: PMC9209706 DOI: 10.3389/fnins.2022.882850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Neural plasticity occurs during developmental stages and is essential for sexual differentiation of the brain and the ensuing sex-dependent behavioral changes in adults. Maternal behavior is primarily affected by sex-related differences in the brain; however, chronic social isolation even in mature male mice can induce maternal retrieving and crouching behavior when they are first exposed to pups. Social milieus influence the inherent behavior of adults and alter the molecular architecture in the brain, thereby allowing higher levels of associated gene expression and molecular activity. This review explores the possibility that although the development of neural circuits is closely associated with maternal behavior, the brain can still retain its neuroplasticity in adults from a neuromolecular perspective. In addition, neuronal machinery such as neurotransmitters and neuropeptides might influence sociobehavioral changes. This review also discusses that the neural circuits regulating behaviors such as parenting and infanticide (including neglect behavior), might be controlled by neural relay on melanin concentrating hormone (MCH)–oxytocin in the hypothalamus during the positive and negative mode of action in maternal behavior. Furthermore, MCH–oxytocin neural relay might contribute to the anxiolytic effect on maternal behavior, which is involved with reward circuits.
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11
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Zhang C, Lin Y, Wu Q, Yan C, Wong MW, Zeng F, Zhu P, Bowes K, Lee K, Zhang X, Song Z, Lin S, Shi Y. Arcuate NPY is involved in salt‐induced hypertension via modulation of paraventricular vasopressin and brain‐derived neurotrophic factor. J Cell Physiol 2022; 237:2574-2588. [PMID: 35312067 PMCID: PMC9544553 DOI: 10.1002/jcp.30719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 02/24/2022] [Accepted: 03/07/2022] [Indexed: 12/17/2022]
Abstract
Chronic high salt intake is one of the leading causes of hypertension. Salt activates the release of the key neurotransmitters in the hypothalamus such as vasopressin to increase blood pressure, and neuropepetide Y (NPY) has been implicated in the modulation of vasopressin levels. NPY in the hypothalamic arcuate nucleus (Arc) is best known for its control in appetite and energy homeostasis, but it is unclear whether it is also involved in the development of salt‐induced hypertension. Here, we demonstrate that wild‐type mice given 2% NaCl salt water for 8 weeks developed hypertension which was associated with marked downregulation of NPY expression in the hypothalamic Arc as demonstrated in NPY‐GFP reporter mice as well as by in situ hybridization analysis. Furthermore, salt intake activates neurons in the hypothalamic paraventricular nucleus (PVN) where mRNA expression of brain‐derived neurotrophic factor (BDNF) and vasopressin was found to be upregulated, leading to elevated serum vasopressin levels. This finding suggests an inverse correlation between the Arc NPY level and expression of vasopressin and BDNF in the PVN. Specific restoration of NPY by injecting AAV‐Cre recombinase into the Arc only of the NPY‐targeted mutant mice carrying a loxP‐flanked STOP cassette reversed effects of salt intake on vasopressin and BDNF expression, leading to a normalization of salt‐dependent blood pressure. In summary, our study uncovers an important Arc NPY‐originated neuronal circuitry that could sense and respond to peripheral electrolyte signals and thereby regulate hypertension via vasopressin and BDNF in the PVN.
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Affiliation(s)
- Chen‐Liang Zhang
- Department of Cardiology, Southwest Hospital Third Military Medical University (Army Medical University) Chongqing China
| | - Yi‐Zhang Lin
- Department of Cardiology, Southwest Hospital Third Military Medical University (Army Medical University) Chongqing China
| | - Qi Wu
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
- The Second Affiliated Hospital Fujian Medical University Quanzhou China
| | - Chenxu Yan
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
- The Second Affiliated Hospital Fujian Medical University Quanzhou China
| | - Matthew Wai‐Kin Wong
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
| | - Fan Zeng
- Department of Cardiology, Southwest Hospital Third Military Medical University (Army Medical University) Chongqing China
| | - Ping Zhu
- Department of Cardiology, Southwest Hospital Third Military Medical University (Army Medical University) Chongqing China
| | - Kelsey Bowes
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
| | - Kailun Lee
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
| | - Xuan Zhang
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
| | - Zhi‐Yuan Song
- Department of Cardiology, Southwest Hospital Third Military Medical University (Army Medical University) Chongqing China
| | - Shu Lin
- Department of Cardiology, Southwest Hospital Third Military Medical University (Army Medical University) Chongqing China
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
- The Second Affiliated Hospital Fujian Medical University Quanzhou China
| | - Yan‐Chuan Shi
- Group of Neuroendocrinology, Diabetes and Metabolism Division Garvan Institute of Medical Research Sydney New South Wales Australia
- St Vincent's Clinical School UNSW Sydney Sydney New South Wales Australia
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12
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Lim WM, Chin EWM, Tang BL, Chen T, Goh ELK. WNK3 Maintains the GABAergic Inhibitory Tone, Synaptic Excitation and Neuronal Excitability via Regulation of KCC2 Cotransporter in Mature Neurons. Front Mol Neurosci 2021; 14:762142. [PMID: 34858138 PMCID: PMC8631424 DOI: 10.3389/fnmol.2021.762142] [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: 08/21/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The activation of chloride (Cl−)permeable gamma (γ)-aminobutyric acid type A(GABAA) receptors induces synaptic inhibition in mature and excitation in immature neurons. This developmental “switch” in GABA function controlled by its polarity depends on the postnatal decrease in intraneuronal Cl− concentration mediated by KCC2, a member of cation-chloride cotransporters (CCCs). The serine-threonine kinase WNK3 (With No Lysine [K]), is a potent regulator of all CCCs and is expressed in neurons. Here, we characterized the functions of WNK3 and its role in GABAergic signaling in cultured embryonic day 18 (E18) hippocampal neurons. We observed a decrease in WNK3 expression as neurons mature. Knocking down of WNK3 significantly hyperpolarized EGABA in mature neurons (DIV13–15) but had no effect on immature neurons (DIV6–8). This hyperpolarized EGABA in WNK3-deficient neurons was not due to the total expression of NKCC1 and KCC2, that remained unchanged. However, there was a reduction in phosphorylated KCC2 at the membrane, suggesting an increase in KCC2 chloride export activity. Furthermore, hyperpolarized EGABA observed in WNK3-deficient neurons can be reversed by the KCC2 inhibitor, VU024055, thus indicating that WNK3 acts through KCC2 to influence EGABA. Notably, WNK3 knockdown resulted in morphological changes in mature but not immature neurons. Electrophysiological characterization of WNK3-deficient mature neurons revealed reduced capacitances but increased intrinsic excitability and synaptic excitation. Hence, our study demonstrates that WNK3 maintains the “adult” GABAergic inhibitory tone in neurons and plays a role in the morphological development of neurons and excitability.
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Affiliation(s)
- Wee Meng Lim
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore
| | - Eunice W M Chin
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore.,Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Bor Luen Tang
- NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Tingting Chen
- School of Pharmacy, Nantong University, Nantong, China
| | - Eyleen L K Goh
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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13
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Al-Kuraishy HM, Al-Gareeb AI, Qusti S, Alshammari EM, Atanu FO, Batiha GES. Arginine vasopressin and pathophysiology of COVID-19: An innovative perspective. Biomed Pharmacother 2021; 143:112193. [PMID: 34543987 PMCID: PMC8440235 DOI: 10.1016/j.biopha.2021.112193] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/06/2021] [Accepted: 09/10/2021] [Indexed: 12/25/2022] Open
Abstract
In Covid-19, systemic disturbances may progress due to development of cytokine storm and dysregulation of and plasma osmolarility due to high release of pro-inflammatory cytokines and neuro-hormonal disorders. Arginine vasopressin (AVP) which is involve in the regulation of body osmotic system, body water content, blood pressure and plasma volume, that are highly disturbed in Covid-19 and linked with poor clinical outcomes. Therefore, this present study aimed to find the potential association between AVP serum level and inflammatory disorders in Covid-19. It has been observed by different recent studies that physiological response due to fever, pain, hypovolemia, dehydration, and psychological stress is characterized by activation release of AVP to counter-balance high blood viscosity in Covid-19 patients. In addition, activated immune cells mainly T and B lymphocytes and released pro-inflammatory cytokines stimulate discharge of stored AVP from immune cells, which in a vicious cycle trigger release of pro-inflammatory cytokines. Vasopressin receptor antagonists have antiviral and anti-inflammatory effects that may inhibit AVP-induced hyponatremia and release of pro-inflammatory cytokines in Covid-19. In conclusion, release of AVP from hypothalamus is augmented in Covid-19 due to stress, high pro-inflammatory cytokines, high circulating AngII and inhibition of GABAergic neurons. In turn, high AVP level leads to induction of hyponatremia, inflammatory disorders, and development of complications in Covid-19 by activation of NF-κB and NLRP3 inflammasome with release of pro-inflammatory cytokines. Therefore, AVP antagonists might be novel potential therapeutic modality in treating Covid-19 through mitigation of AVP-mediated inflammatory disorders and hyponatremia.
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Affiliation(s)
- Hayder M Al-Kuraishy
- Department of Clinical Pharmacology and Medicine, College of Medicine, ALmustansiriyia University, Baghdad, Iraq.
| | - Ali I Al-Gareeb
- Department of Clinical Pharmacology and Medicine, College of Medicine, ALmustansiriyia University, Baghdad, Iraq.
| | - Safaa Qusti
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Eida M Alshammari
- Department of Chemistry, College of Sciences, University of Ha'il, Ha'il, Saudi Arabia.
| | - Francis O Atanu
- Department of Biochemistry, Faculty of Natural Sciences, Kogi State University, P.M.B. 1008 Anyigba, Nigeria.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, AlBeheira, Egypt.
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14
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Yang HJ, Kim MJ, Kim SS, Cho YW. Melatonin modulates nitric oxide-regulated WNK-SPAK/OSR1-NKCC1 signaling in dorsal raphe nucleus of rats. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2021; 25:449-457. [PMID: 34448462 PMCID: PMC8405441 DOI: 10.4196/kjpp.2021.25.5.449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/21/2021] [Accepted: 07/20/2021] [Indexed: 11/15/2022]
Abstract
The sleep-wake cycle is regulated by the alternating activity of sleep- and wake-promoting neurons. The dorsal raphe nucleus (DRN) secretes 5-hydroxytryptamine (5-HT, serotonin), promoting wakefulness. Melatonin secreted from the pineal gland also promotes wakefulness in rats. Our laboratory recently demonstrated that daily changes in nitric oxide (NO) production regulates a signaling pathway involving with-no-lysine kinase (WNK), Ste20-related proline alanine rich kinase (SPAK)/oxidative stress response kinase 1 (OSR1), and cation-chloride co-transporters (CCC) in rat DRN serotonergic neurons. This study was designed to investigate the effect of melatonin on NO-regulated WNK-SPAK/OSR1-CCC signaling in wake-inducing DRN neurons to elucidate the mechanism underlying melatonin's wake-promoting actions in rats. Ex vivo treatment of DRN slices with melatonin suppressed neuronal nitric oxide synthase (nNOS) expression and increased WNK4 expression without altering WNK1, 2, or 3. Melatonin increased phosphorylation of OSR1 and the expression of sodium-potassium-chloride co-transporter 1 (NKCC1), while potassium-chloride cotransporter 2 (KCC2) remained unchanged. Melatonin increased the expression of tryptophan hydroxylase 2 (TPH2, serotonin-synthesizing enzyme). The present study suggests that melatonin may promote its wakefulness by modulating NO-regulated WNK-SPAK/OSR1-KNCC1 signaling in rat DRN serotonergic neurons.
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Affiliation(s)
- Hye Jin Yang
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea
| | - Mi Jung Kim
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul 02447, Korea.,Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, College of Medicine, Kyung Hee University, Seoul 02447, Korea
| | - Sung Soo Kim
- Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, College of Medicine, Kyung Hee University, Seoul 02447, Korea.,Department of Biochemistry and Molecular Biology, College of Medicine, Kyung Hee University, Seoul 02447, Korea
| | - Young-Wuk Cho
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea.,Department of Physiology, College of Medicine, Kyung Hee University, Seoul 02447, Korea.,Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, College of Medicine, Kyung Hee University, Seoul 02447, Korea
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15
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Jin X, Kim WB, Kim MN, Jung WW, Kang HK, Hong EH, Kim YS, Shim WJ, Han HC, Colwell CS, Kim YB, Kim YI. Oestrogen inhibits salt-dependent hypertension by suppressing GABAergic excitation in magnocellular AVP neurons. Cardiovasc Res 2021; 117:2263-2274. [PMID: 32960965 PMCID: PMC10616626 DOI: 10.1093/cvr/cvaa271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/24/2020] [Accepted: 09/08/2020] [Indexed: 12/25/2022] Open
Abstract
AIMS Abundant evidence indicates that oestrogen (E2) plays a protective role against hypertension. Yet, the mechanism underlying the antihypertensive effect of E2 is poorly understood. In this study, we sought to determine the mechanism through which E2 inhibits salt-dependent hypertension. METHODS AND RESULTS To this end, we performed a series of in vivo and in vitro experiments employing a rat model of hypertension that is produced by deoxycorticosterone acetate (DOCA)-salt treatment after uninephrectomy. We found that E2 prevented DOCA-salt treatment from inducing hypertension, raising plasma arginine-vasopressin (AVP) level, enhancing the depressor effect of the V1a receptor antagonist (Phenylac1,D-Tyr(Et)2,Lys6,Arg8,des-Gly9)-vasopressin, and converting GABAergic inhibition to excitation in hypothalamic magnocellular AVP neurons. Moreover, we obtained results indicating that the E2 modulation of the activity and/or expression of NKCC1 (Cl- importer) and KCC2 (Cl- extruder) underpins the effect of E2 on the transition of GABAergic transmission in AVP neurons. Lastly, we discovered that, in DOCA-salt-treated hypertensive ovariectomized rats, CLP290 (prodrug of the KCC2 activator CLP257, intraperitoneal injections) lowered blood pressure, and plasma AVP level and hyperpolarized GABA equilibrium potential to prevent GABAergic excitation from emerging in the AVP neurons of these animals. CONCLUSION Based on these results, we conclude that E2 inhibits salt-dependent hypertension by suppressing GABAergic excitation to decrease the hormonal output of AVP neurons.
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Affiliation(s)
- Xiangyan Jin
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Woong Bin Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Mi-Na Kim
- Department of Internal Medicine, Cardiovascular Section, Korea University Anam Hospital, Seoul 136-705, Republic of Korea
| | - Won Woo Jung
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Hyung Kyung Kang
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Eun-Hwa Hong
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Yoon Sik Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Wan Joo Shim
- Department of Internal Medicine, Cardiovascular Section, Korea University Anam Hospital, Seoul 136-705, Republic of Korea
| | - Hee Chul Han
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA
| | - Young-Beom Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Yang In Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
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16
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Aikins AO, Nguyen DH, Paundralingga O, Farmer GE, Shimoura CG, Brock C, Cunningham JT. Cardiovascular Neuroendocrinology: Emerging Role for Neurohypophyseal Hormones in Pathophysiology. Endocrinology 2021; 162:6247962. [PMID: 33891015 PMCID: PMC8234498 DOI: 10.1210/endocr/bqab082] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Indexed: 11/19/2022]
Abstract
Arginine vasopressin (AVP) and oxytocin (OXY) are released by magnocellular neurosecretory cells that project to the posterior pituitary. While AVP and OXY currently receive more attention for their contributions to affiliative behavior, this mini-review discusses their roles in cardiovascular function broadly defined to include indirect effects that influence cardiovascular function. The traditional view is that neither AVP nor OXY contributes to basal cardiovascular function, although some recent studies suggest that this position might be re-evaluated. More evidence indicates that adaptations and neuroplasticity of AVP and OXY neurons contribute to cardiovascular pathophysiology.
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Affiliation(s)
- Ato O Aikins
- Department of Physiology and Anatomy, Graduate School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX 76107, USA
| | - Dianna H Nguyen
- Department of Physiology and Anatomy, Graduate School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX 76107, USA
- Texas College of Osteopathic Medicine, UNT Health Science Center, Fort Worth, TX 76107, USA
| | - Obed Paundralingga
- Department of Physiology and Anatomy, Graduate School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX 76107, USA
| | - George E Farmer
- Department of Physiology and Anatomy, Graduate School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX 76107, USA
| | - Caroline Gusson Shimoura
- Department of Physiology and Anatomy, Graduate School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX 76107, USA
| | - Courtney Brock
- Department of Physiology and Anatomy, Graduate School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX 76107, USA
| | - J Thomas Cunningham
- Department of Physiology and Anatomy, Graduate School of Biomedical Sciences, UNT Health Science Center, Fort Worth, TX 76107, USA
- Correspondence: J. Thomas Cunningham Department of Physiology & Anatomy CBH 338 UNT Health Science Center 3500 Camp Bowie Blvd Fort Worth, TX 76107, USA.
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17
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Neural Contributions of the Hypothalamus to Parental Behaviour. Int J Mol Sci 2021; 22:ijms22136998. [PMID: 34209728 PMCID: PMC8268030 DOI: 10.3390/ijms22136998] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/23/2022] Open
Abstract
Parental behaviour is a comprehensive set of neural responses to social cues. The neural circuits that govern parental behaviour reside in several putative nuclei in the brain. Melanin concentrating hormone (MCH), a neuromodulator that integrates physiological functions, has been confirmed to be involved in parental behaviour, particularly in crouching behaviour during nursing. Abolishing MCH neurons in innate MCH knockout males promotes infanticide in virgin male mice. To understand the mechanism and function of neural networks underlying parental care and aggression against pups, it is essential to understand the basic organisation and function of the involved nuclei. This review presents newly discovered aspects of neural circuits within the hypothalamus that regulate parental behaviours.
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18
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Bazard P, Frisina RD, Acosta AA, Dasgupta S, Bauer MA, Zhu X, Ding B. Roles of Key Ion Channels and Transport Proteins in Age-Related Hearing Loss. Int J Mol Sci 2021; 22:6158. [PMID: 34200434 PMCID: PMC8201059 DOI: 10.3390/ijms22116158] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/25/2022] Open
Abstract
The auditory system is a fascinating sensory organ that overall, converts sound signals to electrical signals of the nervous system. Initially, sound energy is converted to mechanical energy via amplification processes in the middle ear, followed by transduction of mechanical movements of the oval window into electrochemical signals in the cochlear hair cells, and finally, neural signals travel to the central auditory system, via the auditory division of the 8th cranial nerve. The majority of people above 60 years have some form of age-related hearing loss, also known as presbycusis. However, the biological mechanisms of presbycusis are complex and not yet fully delineated. In the present article, we highlight ion channels and transport proteins, which are integral for the proper functioning of the auditory system, facilitating the diffusion of various ions across auditory structures for signal transduction and processing. Like most other physiological systems, hearing abilities decline with age, hence, it is imperative to fully understand inner ear aging changes, so ion channel functions should be further investigated in the aging cochlea. In this review article, we discuss key various ion channels in the auditory system and how their functions change with age. Understanding the roles of ion channels in auditory processing could enhance the development of potential biotherapies for age-related hearing loss.
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Affiliation(s)
- Parveen Bazard
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Robert D. Frisina
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
- Department Communication Sciences and Disorders, College of Behavioral & Communication Sciences, Tampa, FL 33620, USA
| | - Alejandro A. Acosta
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Sneha Dasgupta
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Mark A. Bauer
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Bo Ding
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
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19
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Levi DI, Wyrosdic JC, Hicks AI, Andrade MA, Toney GM, Prager-Khoutorsky M, Bourque CW. High dietary salt amplifies osmoresponsiveness in vasopressin-releasing neurons. Cell Rep 2021; 34:108866. [PMID: 33730577 PMCID: PMC8049100 DOI: 10.1016/j.celrep.2021.108866] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 04/13/2020] [Accepted: 02/24/2021] [Indexed: 12/28/2022] Open
Abstract
High dietary salt increases arterial pressure partly through activation of magnocellular neurosecretory cells (MNCVP) that secrete the antidiuretic and vasoconstrictor hormone vasopressin (VP) into the circulation. Here, we show that the intrinsic and synaptic excitation of MNCVP caused by hypertonicity are differentially potentiated in two models of salt-dependent hypertension in rats. One model combined salty chow with a chronic subpressor dose of angiotensin II (AngII-salt), the other involved replacing drinking water with 2% NaCl (salt loading, SL). In both models, we observed a significant increase in the quantal amplitude of EPSCs on MNCVP. However, model-specific changes were also observed. AngII-salt increased the probability of glutamate release by osmoreceptor afferents and increased overall excitatory network drive. In contrast, SL specifically increased membrane stiffness and the intrinsic osmosensitivity of MNCVP. These results reveal that dietary salt increases the excitability of MNCVP through effects on the cell-autonomous and synaptic osmoresponsiveness of MNCVP.
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Affiliation(s)
- David I Levi
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada
| | - Joshua C Wyrosdic
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada
| | - Amirah-Iman Hicks
- Department of Physiology, McGill University, 3644 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada
| | - Mary Ann Andrade
- Department of Cellular and Integrative Physiology, University of Texas Health Sciences Centre San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Glenn M Toney
- Department of Cellular and Integrative Physiology, University of Texas Health Sciences Centre San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Masha Prager-Khoutorsky
- Department of Physiology, McGill University, 3644 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada.
| | - Charles W Bourque
- Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada.
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Kato Y, Katsumata H, Inutsuka A, Yamanaka A, Onaka T, Minami S, Orikasa C. Involvement of MCH-oxytocin neural relay within the hypothalamus in murine nursing behavior. Sci Rep 2021; 11:3348. [PMID: 33558633 PMCID: PMC7870840 DOI: 10.1038/s41598-021-82773-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 01/21/2021] [Indexed: 12/22/2022] Open
Abstract
Multiple sequential actions, performed during parental behaviors, are essential elements of reproduction in mammalian species. We showed that neurons expressing melanin concentrating hormone (MCH) in the lateral hypothalamic area (LHA) are more active in rodents of both sexes when exhibiting parental nursing behavior. Genetic ablation of the LHA-MCH neurons impaired maternal nursing. The post-birth survival rate was lower in pups born to female mice with congenitally ablated MCH neurons under control of tet-off system, exhibiting reduced crouching behavior. Virgin female and male mice with ablated MCH neurons were less interested in pups and maternal care. Chemogenetic and optogenetic stimulation of LHA-MCH neurons induced parental nursing in virgin female and male mice. LHA-MCH GABAergic neurons project fibres to the paraventricular hypothalamic nucleus (PVN) neurons. Optogenetic stimulation of PVN induces nursing crouching behavior along with increasing plasma oxytocin levels. The hypothalamic MCH neural relays play important functional roles in parental nursing behavior in female and male mice.
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Affiliation(s)
- Yoko Kato
- Department of Bioregulation, Institute for Advanced Medical Science, Nippon Medical School, Kawasaki, 211-8533, Japan
| | - Harumi Katsumata
- Department of Bioregulation, Institute for Advanced Medical Science, Nippon Medical School, Kawasaki, 211-8533, Japan
| | - Ayumu Inutsuka
- Department of Physiology, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan
| | - Tatsushi Onaka
- Department of Physiology, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan
| | - Shiro Minami
- Department of Bioregulation, Institute for Advanced Medical Science, Nippon Medical School, Kawasaki, 211-8533, Japan
| | - Chitose Orikasa
- Department of Bioregulation, Institute for Advanced Medical Science, Nippon Medical School, Kawasaki, 211-8533, Japan.
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21
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Kim YB, Jung WW, Lee SW, Jin X, Kang HK, Hong EH, Min SS, Kim YS, Han HC, Colwell CS, Kim YI. Excessive maternal salt intake gives rise to vasopressin-dependent salt sensitivity of blood pressure in male offspring. J Mol Cell Cardiol 2021; 150:12-22. [PMID: 33011158 DOI: 10.1016/j.yjmcc.2020.09.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/28/2020] [Accepted: 09/26/2020] [Indexed: 01/11/2023]
Abstract
Salt sensitivity of blood pressure (SSBP) is a trait carrying strong prognostic implications for various cardiovascular diseases. To test the hypothesis that excessive maternal salt intake causes SSBP in offspring through a mechanism dependent upon arginine-vasopressin (AVP), we performed a series of experiments using offspring of the rat dams salt-loaded during pregnancy and lactation with 1.5% saline drink ("experimental offspring") and those with normal perinatal salt exposure ("control offspring"). Salt challenge, given at 7-8 weeks of age with either 2% saline drink (3 days) or 8% NaCl-containing chow (4 weeks), had little or no effect on systolic blood pressure (SBP) in female offspring, whereas the salt challenge significantly raised SBP in male offspring, with the magnitude of increase being greater in experimental, than control, rats. Furthermore, the salt challenge not only raised plasma AVP level more and caused greater depressor responses to V1a and V2 AVP receptor antagonists to occur in experimental, than control, males, but it also made GABA excitatory in a significant proportion of magnocellular AVP neurons of experimental males by depolarizing GABA equilibrium potential. The effect of the maternal salt loading on the salt challenge-elicited SBP response in male offspring was precluded by maternal conivaptan treatment (non-selective AVP receptor antagonist) during the salt-loading period, whereas it was mimicked by neonatal AVP treatment. These results suggest that the excessive maternal salt intake brings about SSBP in male offspring, both the programming and the expression of which depend on increased AVP secretion that may partly result from excitatory GABAergic action.
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Affiliation(s)
- Young-Beom Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Won Woo Jung
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Seung Won Lee
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Xiangyan Jin
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Hyung Kyung Kang
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Eun-Hwa Hong
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Sun Seek Min
- Department of Physiology and Biophysics, Eulji University School of Medicine, Daejeon 34824, Republic of Korea
| | - Yoon-Sik Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Hee Chul Han
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, University of California School of Medicine, Los Angeles, CA, United States of America.
| | - Yang In Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea.
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22
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Unique Organization of Actin Cytoskeleton in Magnocellular Vasopressin Neurons in Normal Conditions and in Response to Salt-Loading. eNeuro 2020; 7:ENEURO.0351-19.2020. [PMID: 32209611 PMCID: PMC7189486 DOI: 10.1523/eneuro.0351-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 12/04/2022] Open
Abstract
Magnocellular neurosecretory cells (MNCs) are intrinsically osmosensitive and can be activated by increases in blood osmolality, triggering the release of antidiuretic hormone vasopressin (VP) to promote water retention. Hence, the activity of magnocellular VP neurons is one of the key elements contributing to the regulation of body fluid homeostasis in healthy organisms. Chronic exposure to high dietary salt leads to excessive activation of VP neurons, thereby elevating levels of circulating VP, which can cause increases in blood pressure contributing to salt-dependent hypertension. However, the molecular basis underlying high-salt diet-induced hyperactivation of magnocellular VP neurons remains not fully understood. Previous studies suggest that magnocellular neurosecretory neurons contain a subcortical layer of actin filaments and pharmacological stabilization of this actin network potentiates osmotically-induced activation of magnocellular neurons. Using super-resolution imaging in situ, we investigated the organization of the actin cytoskeleton in rat MNCs under normal physiological conditions and after a chronic increase in blood osmolality following 7 d of salt-loading (SL). We found that, in addition to the subcortical layer of actin filaments, magnocellular VP neurons are endowed with a unique network of cytoplasmic actin filaments throughout their somata. Moreover, we revealed that the density of both subcortical and cytoplasmic actin networks in magnocellular VP neurons is dramatically increased following SL. These results suggest that increased osmo-responsiveness of VP neurons following chronic exposure to high dietary salt may be mediated by the modulation of unique actin networks in magnocellular VP neurons, possibly contributing to elevated blood pressure in this condition.
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23
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Tasker JG, Prager-Khoutorsky M, Teruyama R, Lemos JR, Amstrong WE. Advances in the neurophysiology of magnocellular neuroendocrine cells. J Neuroendocrinol 2020; 32:e12826. [PMID: 31917875 PMCID: PMC7192795 DOI: 10.1111/jne.12826] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/02/2020] [Accepted: 01/07/2020] [Indexed: 02/06/2023]
Abstract
Hypothalamic magnocellular neuroendocrine cells have unique electrical properties and a remarkable capacity for morphological and synaptic plasticity. Their large somatic size, their relatively uniform and dense clustering in the supraoptic and paraventricular nuclei, and their large axon terminals in the neurohypophysis make them an attractive target for direct electrophysiological interrogation. Here, we provide a brief review of significant recent findings in the neuroplasticity and neurophysiological properties of these neurones that were presented at the symposium "Electrophysiology of Magnocellular Neurons" during the 13th World Congress on Neurohypophysial Hormones in Ein Gedi, Israel in April 2019. Magnocellular vasopressin (VP) neurones respond directly to hypertonic stimulation with membrane depolarisation, which is triggered by cell shrinkage-induced opening of an N-terminal-truncated variant of transient receptor potential vanilloid type-1 (TRPV1) channels. New findings indicate that this mechanotransduction depends on actin and microtubule cytoskeletal networks, and that direct coupling of the TRPV1 channels to microtubules is responsible for mechanical gating of the channels. Vasopressin neurones also respond to osmostimulation by activation of epithelial Na+ channels (ENaC). It was shown recently that changes in ENaC activity modulate magnocellular neurone basal firing by generating tonic changes in membrane potential. Both oxytocin and VP neurones also undergo robust excitatory synapse plasticity during chronic osmotic stimulation. Recent findings indicate that new glutamate synapses induced during chronic salt loading express highly labile Ca2+ -permeable GluA1 receptors requiring continuous dendritic protein synthesis for synapse maintenance. Finally, recordings from the uniquely tractable neurohypophysial terminals recently revealed an unexpected property of activity-dependent neuropeptide release. A significant fraction of the voltage-dependent neurohypophysial neurosecretion was found to be independent of Ca2+ influx through voltage-gated Ca2+ channels. Together, these findings provide a snapshot of significant new advances in the electrophysiological signalling mechanisms and neuroplasticity of the hypothalamic-neurohypophysial system, a system that continues to make important contributions to the field of neurophysiology.
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Affiliation(s)
- Jeffrey G. Tasker
- Department of Cell and Molecular Biology and Tulane Brain Institute, Tulane University, New Orleans, LA, USA
- Correspondence: Jeffrey Tasker, PhD, Tulane University, Cell and Molecular Biology Dept, 2000 Percival Stern Hall, New Orleans, LA 70118, USA; .; William Armstrong, PhD, University of Tennessee Health Science Center, Anatomy and Neurobiology Dept and Neuroscience Institute, 855 Monroe Ave, Memphis, TN 38163, USA;
| | | | - Ryoichi Teruyama
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - José R. Lemos
- Department of Microbiology and Physiological Systems & Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA, USA
| | - William E. Amstrong
- Department of Anatomy and Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA
- Correspondence: Jeffrey Tasker, PhD, Tulane University, Cell and Molecular Biology Dept, 2000 Percival Stern Hall, New Orleans, LA 70118, USA; .; William Armstrong, PhD, University of Tennessee Health Science Center, Anatomy and Neurobiology Dept and Neuroscience Institute, 855 Monroe Ave, Memphis, TN 38163, USA;
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24
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Kim YB, Colwell CS, Kim YI. Long-term ionic plasticity of GABAergic signalling in the hypothalamus. J Neuroendocrinol 2019; 31:e12753. [PMID: 31166034 DOI: 10.1111/jne.12753] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 05/24/2019] [Accepted: 06/03/2019] [Indexed: 12/23/2022]
Abstract
The hypothalamus contains a number of nuclei that subserve a variety of functions, including generation of circadian rhythms, regulation of hormone secretion and maintenance of homeostatic levels for a variety of physiological parameters. Within the hypothalamus, γ-amino-butyric acid (GABA) is one of the major neurotransmitters responsible for cellular communication. Although GABA most commonly serves as an inhibitory neurotransmitter, a growing body of evidence indicates that it can evoke post-synaptic excitation as a result of the active regulation of intracellular chloride concentration. In this review, we consider the evidence for this ionic plasticity of GABAergic synaptic transmission in five distinct cases in hypothalamic cell populations. We argue that this plasticity serves as part of the functional response to or is at least associated with dehydration, lactation, hypertension and stress. As such, GABA excitation should be considered as part of the core homeostatic mechanisms of the hypothalamus.
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Affiliation(s)
- Young-Beom Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Korea
- Neuroscience Research Institute, Korea University, Seoul, Korea
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, UCLA School of Medicine, Los Angeles, CA, USA
| | - Yang In Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Korea
- Neuroscience Research Institute, Korea University, Seoul, Korea
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25
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Armstrong WE, Foehring RC, Kirchner MK, Sladek CD. Electrophysiological properties of identified oxytocin and vasopressin neurones. J Neuroendocrinol 2019; 31:e12666. [PMID: 30521104 PMCID: PMC7251933 DOI: 10.1111/jne.12666] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/26/2018] [Accepted: 11/29/2018] [Indexed: 12/18/2022]
Abstract
To understand the contribution of intrinsic membrane properties to the different in vivo firing patterns of oxytocin (OT) and vasopressin (VP) neurones, in vitro studies are needed, where stable intracellular recordings can be made. Combining immunochemistry for OT and VP and intracellular dye injections allows characterisation of identified OT and VP neurones, and several differences between the two cell types have emerged. These include a greater transient K+ current that delays spiking to stimulus onset, and a higher Na+ current density leading to greater spike amplitude and a more stable spike threshold, in VP neurones. VP neurones also show a greater incidence of both fast and slow Ca2+ -dependent depolarising afterpotentials, the latter of which summate to plateau potentials and contribute to phasic bursting. By contrast, OT neurones exhibit a sustained outwardly rectifying potential (SOR), as well as a consequent depolarising rebound potential, not found in VP neurones. The SOR makes OT neurones more susceptible to spontaneous inhibitory synaptic inputs and correlates with a longer period of spike frequency adaptation in these neurones. Although both types exhibit prominent Ca2+ -dependent afterhyperpolarising potentials (AHPs) that limit firing rate and contribute to bursting patterns, Ca2+ -dependent AHPs in OT neurones selectively show significant increases during pregnancy and lactation. In OT neurones, but not VP neurones, AHPs are highly dependent on the constitutive presence of the second messenger, phosphatidylinositol 4,5-bisphosphate, which permissively gates N-type channels that contribute the Ca2+ during spike trains that activates the AHP. By contrast to the intrinsic properties supporting phasic bursting in VP neurones, the synchronous bursting of OT neurones has only been demonstrated in vitro in cultured hypothalamic explants and is completely dependent on synaptic transmission. Additional differences in Ca2+ channel expression between the two neurosecretory terminal types suggests these channels are also critical players in the differential release of OT and VP during repetitive spiking, in addition to their importance to the potentials controlling firing patterns.
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Affiliation(s)
- William E Armstrong
- Department of Anatomy & Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Robert C Foehring
- Department of Anatomy & Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Matthew K Kirchner
- Department of Anatomy & Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Celia D Sladek
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado
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26
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Lopatina OL, Komleva YK, Gorina YV, Olovyannikova RY, Trufanova LV, Hashimoto T, Takahashi T, Kikuchi M, Minabe Y, Higashida H, Salmina AB. Oxytocin and excitation/inhibition balance in social recognition. Neuropeptides 2018; 72:1-11. [PMID: 30287150 DOI: 10.1016/j.npep.2018.09.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 09/18/2018] [Accepted: 09/18/2018] [Indexed: 12/15/2022]
Abstract
Social recognition is the sensitive domains of complex behavior critical for identification, interpretation and storage of socially meaningful information. Social recognition develops throughout childhood and adolescent, and is affected in a wide variety of psychiatric disorders. Recently, new data appeared on the molecular mechanisms of these processes, particularly, the excitatory-inhibitory (E/I) ratio which is modified during development, and then E/I balance is established in the adult brain. While E/I imbalance has been proposed as a mechanism for schizophrenia, it also seems to be the common mechanism in autism spectrum disorder (ASD). In addition, there is a strong suggestion that the oxytocinergic system is related to GABA-mediated E/I control in the context of brain socialization. In this review, we attempt to summarize the underpinning molecular mechanisms of E/I balance and its imbalance, and related biomarkers in the brain in healthiness and pathology. In addition, because there are increasing interest on oxytocin in the social neuroscience field, we will pay intensive attention to the role of oxytocin in maintaining E/I balance from the viewpoint of its effects on improving social impairment in psychiatric diseases, especially in ASD.
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Affiliation(s)
- Olga L Lopatina
- Depatment of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Krasnoyarsk 660022, Russia; Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Yulia K Komleva
- Depatment of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Krasnoyarsk 660022, Russia
| | - Yana V Gorina
- Depatment of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Krasnoyarsk 660022, Russia
| | - Raisa Ya Olovyannikova
- Depatment of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Krasnoyarsk 660022, Russia
| | - Lyudmila V Trufanova
- Depatment of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Krasnoyarsk 660022, Russia
| | - Takanori Hashimoto
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Tetsuya Takahashi
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Mitsuru Kikuchi
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Yoshio Minabe
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Haruhiro Higashida
- Depatment of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Krasnoyarsk 660022, Russia; Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan
| | - Alla B Salmina
- Depatment of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Krasnoyarsk 660022, Russia; Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa 920-8640, Japan.
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27
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Balapattabi K, Little JT, Farmer GE, Cunningham JT. High salt loading increases brain derived neurotrophic factor in supraoptic vasopressin neurones. J Neuroendocrinol 2018; 30:e12639. [PMID: 30129982 PMCID: PMC6645701 DOI: 10.1111/jne.12639] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/07/2018] [Accepted: 08/16/2018] [Indexed: 12/11/2022]
Abstract
High salt loading (SL) is associated with inappropriate arginine vasopressin (AVP) release and increased mean arterial pressure. Previous work has shown that chronic high salt intake impairs baroreceptor inhibition of rat AVP neurones through brain-derived neurotrophic factor (BDNF) dependent activation of tyrosine receptor kinase B (TrkB) and down-regulation of K+/Cl- co-transporter KCC2. This mechanism diminishes the GABAA inhibition of AVP neurones in the supraoptic nucleus (SON) by increasing intracellular chloride. However, the source of BDNF leading to this ionic plasticity is unknown. In the present study, we used adeno-associated viral vectors with short hairpin RNA against BDNF to test whether SON is the source of BDNF contributing to increased AVP release and elevated mean arterial pressure in high salt loaded rats. Virally mediated BDNF knockdown (shBDNF) in the SON of salt loaded rats significantly blocked the increases in BDNF mRNA and AVP heterogeneous RNA expression. The observed increase in the activation of TrkB receptor during salt loading is consistent with previous studies. Western blot analysis of SON punches revealed that tyrosine phosphorylation of TrkB (pTrkBY515) was significantly decreased in salt shBDNF rats compared to the salt scrambled (SCR) rats. Injections of shBDNF in the SON also significantly prevented the increase in plasma AVP concentration associated with salt loading. However, the salt loading induced increase in mean arterial pressure was not decreased with BDNF knockdown in the SON. Average daily fluid intake and urine output were significantly elevated in both salt SCR and salt shBDNF rats compared to the euhydrated controls. Daily average urine sodium concentration was significantly higher in shBDNF injected salt rats than the other groups. These findings indicate that BDNF produced in the SON contributes to the increased AVP secretion during high salt loading but not with respect to the subsequent increase in mean arterial pressure.
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Affiliation(s)
- Kirthikaa Balapattabi
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas
| | - Joel T Little
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas
| | - George E Farmer
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas
| | - J Thomas Cunningham
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas
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28
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Ben-Ari Y. Oxytocin and Vasopressin, and the GABA Developmental Shift During Labor and Birth: Friends or Foes? Front Cell Neurosci 2018; 12:254. [PMID: 30186114 PMCID: PMC6110879 DOI: 10.3389/fncel.2018.00254] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/24/2018] [Indexed: 12/15/2022] Open
Abstract
Oxytocin (OT) and vasopressin (AVP) are usually associated with sociability and reduced stress for the former and antidiuretic agent associated with severe stress and pathological conditions for the latter. Both OT and AVP play major roles during labor and birth. Recent contradictory studies suggest that they might exert different roles on the GABA excitatory/inhibitory developmental shift. We reported (Tyzio et al., 2006) that at birth, OT exerts a neuro-protective action mediated by an abrupt reduction of intracellular chloride levels ([Cl-]i) that are high in utero, reinforcing GABAergic inhibition and modulating the generation of the first synchronized patterns of cortical networks. This reduction of [Cl-]i levels is abolished in rodent models of Fragile X Syndrome and Autism Spectrum Disorders, and its restoration attenuates the severity of the pathological sequels, stressing the importance of the shift at birth (Tyzio et al., 2014). In contrast, Kaila and co-workers (Spoljaric et al., 2017) reported excitatory GABA actions before and after birth that are modulated by AVP but not by OT, challenging both the developmental shift and the roles of OT. Here, I analyze the differences between these studies and suggest that the ratio AVP/OT like that of excitatory/inhibitory GABA depend on stress and pathological conditions.
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Affiliation(s)
- Yehezkel Ben-Ari
- Neurochlore and Ben-Ari Institute of Neuroarcheology (IBEN), Marseille, France
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29
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Han RT, Kim YB, Park EH, Kim JY, Ryu C, Kim HY, Lee J, Pahk K, Shanyu C, Kim H, Back SK, Kim HJ, Kim YI, Na HS. Long-Term Isolation Elicits Depression and Anxiety-Related Behaviors by Reducing Oxytocin-Induced GABAergic Transmission in Central Amygdala. Front Mol Neurosci 2018; 11:246. [PMID: 30158853 PMCID: PMC6104450 DOI: 10.3389/fnmol.2018.00246] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 06/26/2018] [Indexed: 01/29/2023] Open
Abstract
Isolation stress is a major risk factor for neuropsychiatric disorders such as depressive and anxiety disorders. However, the molecular mechanisms underlying isolation-induced neuropsychiatric disorders remain elusive. In the present study, we investigated the subcellular mechanisms by which long-term isolation elicits depression and anxiety-related behaviors in mice. First, we found that long-term isolation induced depression-related behaviors in the forced swimming test (FST) and the sucrose preference test, as well as anxiety-related behaviors in the elevated zero maze test (EZMT) and the open field test. Next, we showed that intracentral amygdala (CeA) injection of oxytocin (OXT), but not intracerebroventricular injection, attenuated isolation-induced depression and anxiety-related behaviors via oxytocin receptor (OXTR), not vasopressin-1a receptor (V1aR), in the FST and EZMT, respectively. Quantitative real-time polymerase chain reaction analysis revealed that after 5 weeks of isolation, mRNA transcription of OXTR in the CeA, but not that of V1aR, significantly decreased, whereas OXT and vasopressin mRNA transcription in the paraventricular nucleus of hypothalamus did not change significantly. Whole-cell patch clamping of acute brain slices demonstrated that the frequency of miniature inhibitory postsynaptic currents (mIPSCs) in CeA neurons, but not their amplitude, was lower in isolated mice than in group-housed mice. Notably, OXT treatment increased the mIPSC frequency in the CeA neurons, but to a lesser extent in the case of isolated mice than in that of group-housed mice via OXTR. Taken together, our findings suggest that long-term isolation down-regulates OXTR mRNA transcription and diminishes OXT-induced inhibitory synaptic transmission in the CeA and may contribute to the development of depression and anxiety-related behaviors in isolated mice through the enhancement of CeA activity.
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Affiliation(s)
- Rafael T Han
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
| | - Young-Beom Kim
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
| | - Eui-Ho Park
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
| | - Jin Yong Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, South Korea
| | - Changhyeon Ryu
- Neuroscience Research Institute and Department of Physiology, College of Medicine, Seoul National University, Seoul, South Korea
| | - Hye Y Kim
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
| | - JaeHee Lee
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
| | - Kisoo Pahk
- Department of Neuroscience, Korea University College of Medicine, Seoul, South Korea
| | - Cui Shanyu
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
| | - Hyun Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, South Korea
| | - Seung K Back
- Department of Pharmaceutics and Biotechnology, College of Medical Engineering, Konyang University, Chungnam, South Korea
| | - Hee J Kim
- Division of Biological Science and Technology, Science and Technology College, Yonsei University, Wonju, South Korea
| | - Yang In Kim
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
| | - Heung S Na
- Neuroscience Research Institute and Department of Physiology, Korea University College of Medicine, Seoul, South Korea
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Wang YF, Parpura V. Astroglial Modulation of Hydromineral Balance and Cerebral Edema. Front Mol Neurosci 2018; 11:204. [PMID: 29946238 PMCID: PMC6007284 DOI: 10.3389/fnmol.2018.00204] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
Maintenance of hydromineral balance (HB) is an essential condition for life activity at cellular, tissue, organ and system levels. This activity has been considered as a function of the osmotic regulatory system that focuses on hypothalamic vasopressin (VP) neurons, which can reflexively release VP into the brain and blood to meet the demand of HB. Recently, astrocytes have emerged as an essential component of the osmotic regulatory system in addition to functioning as a regulator of the HB at cellular and tissue levels. Astrocytes express all the components of osmoreceptors, including aquaporins, molecules of the extracellular matrix, integrins and transient receptor potential channels, with an operational dynamic range allowing them to detect and respond to osmotic changes, perhaps more efficiently than neurons. The resultant responses, i.e., astroglial morphological and functional plasticity in the supraoptic and paraventricular nuclei, can be conveyed, physically and chemically, to adjacent VP neurons, thereby influencing HB at the system level. In addition, astrocytes, particularly those in the circumventricular organs, are involved not only in VP-mediated osmotic regulation, but also in regulation of other osmolality-modulating hormones, including natriuretic peptides and angiotensin. Thus, astrocytes play a role in local/brain and systemic HB. The adaptive astrocytic reactions to osmotic challenges are associated with signaling events related to the expression of glial fibrillary acidic protein and aquaporin 4 to promote cell survival and repair. However, prolonged osmotic stress can initiate inflammatory and apoptotic signaling processes, leading to glial dysfunction and a variety of brain diseases. Among many diseases of brain injury and hydromineral disorders, cytotoxic and osmotic cerebral edemas are the most common pathological manifestation. Hyponatremia is the most common cause of osmotic cerebral edema. Overly fast correction of hyponatremia could lead to central pontine myelinolysis. Ischemic stroke exemplifies cytotoxic cerebral edema. In this review, we summarize and analyze the osmosensory functions of astrocytes and their implications in cerebral edema.
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Affiliation(s)
- Yu-Feng Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, United States
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31
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Kim MJ, Yang HJ, Kim Y, Kang I, Kim SS, Cho YW. Role of nitric oxide and WNK-SPAK/OSR1-KCC2 signaling in daily changes in GABAergic inhibition in the rat dorsal raphe neurons. Neuropharmacology 2018; 135:355-367. [PMID: 29596900 DOI: 10.1016/j.neuropharm.2018.03.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 03/23/2018] [Accepted: 03/24/2018] [Indexed: 11/20/2022]
Abstract
Serotonergic neurons in the dorsal raphe nucleus (DRN) act as wake-inducing neurons in the sleep-wake cycle and are controlled by gamma-aminobutyric acid (GABA) synaptic inputs. We investigated daily changes in GABAergic inhibition of the rat DRN neurons and the role of nitric oxide (NO) and cation-chloride co-transporters in the GABAergic action. Neuronal NO synthase (nNOS) was co-expressed in 74% of serotonergic DRN neurons and nNOS expression was higher during daytime (the sleep cycle) than that during nighttime (the wake cycle). GABAergic hyperpolarization of DRN neurons produced by GABAA receptor agonist muscimol was greater and the equilibrium potential of muscimol showed a hyperpolarizing shift during daytime compared to that during nighttime. Expression levels of potassium-chloride co-transporter 2 (KCC2) were higher during daytime than that during nighttime, whereas there were no changes in sodium-potassium-chloride co-transporter 1 (NKCC1) expression. With-no-lysine kinase (WNK) isoform 1 was more highly expressed during daytime than that during nighttime. Total Ste20-related proline alanine rich kinase (SPAK) and oxidative stress response kinase 1 (OSR1) were also higher during daytime than during nighttime, while there were no changes in phosphorylated SPAK and OSR1. Consistent with the findings during the sleep-wake cycle, ex vivo treatment of DRN slices with a NO donor sodium nitroprusside (SNP) increased the expression of KCC2, WNK1, WNK2, WNK3, SPAK, and OSR1, whilst decreasing phosphorylated SPAK. These results suggest that GABAergic synaptic inhibition of DRN serotonergic neurons shows daily changes during the sleep-wake cycle, which might be regulated by daily changes in nNOS-derived NO and WNK-SPAK/OSR1-KCC2 signaling.
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Affiliation(s)
- Mi Jung Kim
- Department of Physiology, Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, School of Medicine, Kyung Hee University, Seoul 02447, South Korea
| | - Hye Jin Yang
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, South Korea
| | - Younghoon Kim
- Department of Physiology, Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, School of Medicine, Kyung Hee University, Seoul 02447, South Korea
| | - Insug Kang
- Department of Biochemistry and Molecular Biology, Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, School of Medicine, Kyung Hee University, Seoul 02447, South Korea
| | - Sung Soo Kim
- Department of Biochemistry and Molecular Biology, Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, School of Medicine, Kyung Hee University, Seoul 02447, South Korea
| | - Young-Wuk Cho
- Department of Physiology, Biomedical Science Institute and Medical Research Center for Reactive Oxygen Species, School of Medicine, Kyung Hee University, Seoul 02447, South Korea; Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, South Korea.
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32
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Kim YB, Kim WB, Jung WW, Jin X, Kim YS, Kim B, Han HC, Block GD, Colwell CS, Kim YI. Excitatory GABAergic Action and Increased Vasopressin Synthesis in Hypothalamic Magnocellular Neurosecretory Cells Underlie the High Plasma Level of Vasopressin in Diabetic Rats. Diabetes 2018; 67:486-495. [PMID: 29212780 DOI: 10.2337/db17-1042] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/20/2017] [Indexed: 11/13/2022]
Abstract
Diabetes mellitus (DM) is associated with increased plasma levels of arginine-vasopressin (AVP), which may aggravate hyperglycemia and nephropathy. However, the mechanisms by which DM may cause the increased AVP levels are not known. Electrophysiological recordings in supraoptic nucleus (SON) slices from streptozotocin (STZ)-induced DM rats and vehicle-treated control rats revealed that γ-aminobutyric acid (GABA) functions generally as an excitatory neurotransmitter in the AVP neurons of STZ rats, whereas it usually evokes inhibitory responses in the cells of control animals. Furthermore, Western blotting analyses of Cl- transporters in the SON tissues indicated that Na+-K+-2Cl- cotransporter isotype 1 (a Cl- importer) was upregulated and K+-Cl- cotransporter isotype 2 (KCC2; a Cl- extruder) was downregulated in STZ rats. Treatment with CLP290 (a KCC2 activator) significantly lowered blood AVP and glucose levels in STZ rats. Last, investigation that used rats expressing an AVP-enhanced green fluorescent protein fusion gene showed that AVP synthesis in AVP neurons was much more intense in STZ rats than in control rats. We conclude that altered Cl- homeostasis that makes GABA excitatory and enhanced AVP synthesis are important changes in AVP neurons that would increase AVP secretion in DM. Our data suggest that Cl- transporters in AVP neurons are potential targets of antidiabetes treatments.
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Affiliation(s)
- Young-Beom Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
- Neuroscience Research Institute, Korea University College of Medicine, Seoul, Republic of Korea
| | - Woong Bin Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
- Neuroscience Research Institute, Korea University College of Medicine, Seoul, Republic of Korea
| | - Won Woo Jung
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Xiangyan Jin
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Yoon Sik Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
- Department of Psychiatry & Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA
| | - Byoungjae Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Hee Chul Han
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
- Neuroscience Research Institute, Korea University College of Medicine, Seoul, Republic of Korea
| | - Gene D Block
- Department of Psychiatry & Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA
| | - Christopher S Colwell
- Department of Psychiatry & Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA
| | - Yang In Kim
- Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
- Neuroscience Research Institute, Korea University College of Medicine, Seoul, Republic of Korea
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33
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Abstract
PURPOSE OF REVIEW The central nervous system plays a pivotal role in the regulation of extracellular fluid volume and consequently arterial blood pressure. Key hypothalamic regions sense and integrate neurohumoral signals to subsequently alter intake (thirst and salt appetite) and output (renal excretion via neuroendocrine and autonomic function). Here, we review recent findings that provide new insight into such mechanisms that may represent new therapeutic targets. RECENT FINDINGS Implementation of cutting edge neuroscience approaches such as opto- and chemogenetics highlight pivotal roles of circumventricular organs to impact body fluid homeostasis. Key signaling mechanisms within these areas include the N-terminal variant of transient receptor potential vannilloid type-1, NaX, epithelial sodium channel, brain electroneutral transporters, and non-classical actions of vasopressin. Despite the identification of several new mechanisms, future studies need to better define the neurochemical phenotype and molecular profiles of neurons within circumventricular organs for future therapeutic potential.
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Korpal AK, Han SY, Schwenke DO, Brown CH. A switch from GABA inhibition to excitation of vasopressin neurons exacerbates the development angiotensin II-dependent hypertension. J Neuroendocrinol 2017; 30. [PMID: 29222949 DOI: 10.1111/jne.12564] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022]
Abstract
Hypothalamic magnocellular neurons secrete vasopressin into the systemic circulation to maintain blood pressure by increasing renal water reabsorption and by vasoconstriction. When blood pressure rises, baroreflex activation normally inhibits vasopressin neurons via activation of GABAergic inputs. However, plasma vasopressin levels are paradoxically elevated in several models of hypertension and in some patients with essential hypertension, despite increased blood pressure. We have previously shown that vasopressin neuron activity is increased early in the development of moderate angiotensin II-dependent hypertension via blunted baroreflex inhibition of vasopressin neurons. Here, we show that antagonism of vasopressin-induced vasoconstriction slows the development of hypertension and that local administration of a GABAA receptor antagonist inhibits vasopressin neurons during, but not before, the onset of hypertension. Taken together, our data suggest that vasopressin exacerbates the increase in blood pressure evident early in the development hypertension and that blunted baroreflex inhibition of vasopressin neurons is underpinned by an excitatory shift in their response to endogenous GABA signalling. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Aaron K Korpal
- Brain Health Research Centre University of Otago, Dunedin, New Zealand
- Centre for, Neuroendocrinology University of Otago, Dunedin, New Zealand
- Heart Otago and University of Otago, Dunedin, New Zealand
| | - Su Young Han
- Brain Health Research Centre University of Otago, Dunedin, New Zealand
- Centre for, Neuroendocrinology University of Otago, Dunedin, New Zealand
- Heart Otago and University of Otago, Dunedin, New Zealand
| | - Daryl O Schwenke
- Heart Otago and University of Otago, Dunedin, New Zealand
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Colin H Brown
- Brain Health Research Centre University of Otago, Dunedin, New Zealand
- Centre for, Neuroendocrinology University of Otago, Dunedin, New Zealand
- Heart Otago and University of Otago, Dunedin, New Zealand
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35
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Prager-Khoutorsky M, Choe KY, Levi DI, Bourque CW. Role of Vasopressin in Rat Models of Salt-Dependent Hypertension. Curr Hypertens Rep 2017; 19:42. [PMID: 28451854 DOI: 10.1007/s11906-017-0741-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW Dietary salt intake increases both plasma sodium and osmolality and therefore increases vasopressin (VP) release from the neurohypophysis. Although this effect could increase blood pressure by inducing fluid reabsorption and vasoconstriction, acute activation of arterial baroreceptors inhibits VP neurons via GABAA receptors to oppose high blood pressure. Here we review recent findings demonstrating that this protective mechanism fails during chronic high salt intake in rats. RECENT FINDINGS Two recent studies showed that chronic high sodium intake causes an increase in intracellular chloride concentration in VP neurons. This effect causes GABAA receptors to become excitatory and leads to the emergence of VP-dependent hypertension. One study showed that the increase in intracellular chloride was provoked by a decrease in the expression of the chloride exporter KCC2 mediated by local secretion of brain-derived neurotrophic factor and activation of TrkB receptors. Prolonged high dietary salt intake can cause pathological plasticity in a central homeostatic circuit that controls VP secretion and thereby contribute to peripheral vasoconstriction and hypertension.
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Affiliation(s)
- Masha Prager-Khoutorsky
- Department of Physiology, McGill University, McIntyre Medical Sciences Bldg., 3655 Promenade Sir-William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Katrina Y Choe
- 2309 Gonda Neuroscience and Genetics Research Center, UCLA Department of Neurology, 695 Charles E. Young Dr. South, Los Angeles, CA, 90095, USA
| | - David I Levi
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC, H3G 1A4, Canada
| | - Charles W Bourque
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC, H3G 1A4, Canada.
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36
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Ben-Ari Y. NKCC1 Chloride Importer Antagonists Attenuate Many Neurological and Psychiatric Disorders. Trends Neurosci 2017; 40:536-554. [PMID: 28818303 DOI: 10.1016/j.tins.2017.07.001] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/03/2017] [Accepted: 07/10/2017] [Indexed: 12/23/2022]
Abstract
In physiological conditions, adult neurons have low intracellular Cl- [(Cl-)I] levels underlying the γ-aminobutyric acid (GABA)ergic inhibitory drive. In contrast, neurons have high (Cl-)I levels and excitatory GABA actions in a wide range of pathological conditions including spinal cord lesions, chronic pain, brain trauma, cerebrovascular infarcts, autism, Rett and Down syndrome, various types of epilepsies, and other genetic or environmental insults. The diuretic highly specific NKCC1 chloride importer antagonist bumetanide (PubChem CID: 2461) efficiently restores low (Cl-)I levels and attenuates many disorders in experimental conditions and in some clinical trials. Here, I review the mechanisms of action, therapeutic effects, promises, and pitfalls of bumetanide.
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Affiliation(s)
- Yehezkel Ben-Ari
- New INMED, Aix-Marseille University, Campus Scientifique de Luminy, Marseilles, France.
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37
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Stocker SD, Kinsman BJ, Sved AF. Recent Advances in Neurogenic Hypertension: Dietary Salt, Obesity, and Inflammation. Hypertension 2017; 70:HYPERTENSIONAHA.117.08936. [PMID: 28739972 PMCID: PMC5783795 DOI: 10.1161/hypertensionaha.117.08936] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neurally-mediated hypertension results from a dysregulation of sympathetic and/or neuroendocrine mechanisms to increase ABP. Multiple factors may exert multiple central effects to alter neural circuits and produce unique sympathetic signatures and elevate ABP. In this brief review, we have discussed novel observations regarding three contributing factors: dietary salt intake, obesity, and inflammation. However, the interaction among these and other factors is likely much more complex; recent studies suggest a prior exposure to one stimulus may sensitize the response to a subsequent hypertensive stimulus. Insight into the central mechanisms by which these factors selectively alter SNA or cooperatively interact to impact hypertension may represent a platform for novel therapeutic treatment strategies.
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Affiliation(s)
- Sean D Stocker
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA.
| | - Brian J Kinsman
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA
| | - Alan F Sved
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA
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38
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Dos Santos Moreira MC, Naves LM, Marques SM, Silva EF, Rebelo AC, Colombari E, Pedrino GR. Neuronal circuits involved in osmotic challenges. Physiol Res 2017; 66:411-423. [PMID: 28248529 DOI: 10.33549/physiolres.933373] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The maintenance of plasma sodium concentration within a narrow limit is crucial to life. When it differs from normal physiological patterns, several mechanisms are activated in order to restore body fluid homeostasis. Such mechanisms may be vegetative and/or behavioral, and several regions of the central nervous system (CNS) are involved in their triggering. Some of these are responsible for sensory pathways that perceive a disturbance of the body fluid homeostasis and transmit information to other regions. These regions, in turn, initiate adequate adjustments in order to restore homeostasis. The main cardiovascular and autonomic responses to a change in plasma sodium concentration are: i) changes in arterial blood pressure and heart rate; ii) changes in sympathetic activity to the renal system in order to ensure adequate renal sodium excretion/absorption, and iii) the secretion of compounds involved in sodium ion homeostasis (ANP, Ang-II, and ADH, for example). Due to their cardiovascular effects, hypertonic saline solutions have been used to promote resuscitation in hemorrhagic patients, thereby increasing survival rates following trauma. In the present review, we expose and discuss the role of several CNS regions involved in body fluid homeostasis and the effects of acute and chronic hyperosmotic challenges.
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Affiliation(s)
- M C Dos Santos Moreira
- Department of Physiological Science, Federal University of Goiás, Goiânia - GO - Brazil. or
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39
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Banerjee P, Joy KP, Chaube R. Structural and functional diversity of nonapeptide hormones from an evolutionary perspective: A review. Gen Comp Endocrinol 2017; 241:4-23. [PMID: 27133544 DOI: 10.1016/j.ygcen.2016.04.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 04/09/2016] [Accepted: 04/25/2016] [Indexed: 01/08/2023]
Abstract
The article presents an overview of the comparative distribution, structure and functions of the nonapeptide hormones in chordates and non chordates. The review begins with a historical preview of the advent of the concept of neurosecretion and birth of neuroendocrine science, pioneered by the works of E. Scharrer and W. Bargmann. The sections which follow discuss different vertebrate nonapeptides, their distribution, comparison, precursor gene structures and processing, highlighting the major differences in these aspects amidst the conserved features across vertebrates. The vast literature on the anatomical characteristics of the nonapeptide secreting nuclei in the brain and their projections was briefly reviewed in a comparative framework. Recent knowledge on the nonapeptide hormone receptors and their intracellular signaling pathways is discussed and few grey areas which require deeper studies are identified. The sections on the functions and regulation of nonapeptides summarize the huge and ever increasing literature that is available in these areas. The nonapeptides emerge as key homeostatic molecules with complex regulation and several synergistic partners. Lastly, an update of the nonapeptides in non chordates with respect to distribution, site of synthesis, functions and receptors, dealt separately for each phylum, is presented. The non chordate nonapeptides share many similarities with their counterparts in vertebrates, pointing the system to have an ancient origin and to be an important substrate for changes during adaptive evolution. The article concludes projecting the nonapeptides as one of the very first common molecules of the primitive nervous and endocrine systems, which have been retained to maintain homeostatic functions in metazoans; some of which are conserved across the animal kingdom and some are specialized in a group/lineage-specific manner.
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Affiliation(s)
- P Banerjee
- Department of Zoology, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005, India
| | - K P Joy
- Department of Biotechnology, Cochin University of Science and Technology, Kochi 682022, India.
| | - R Chaube
- Department of Zoology, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005, India
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40
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Gao Y, Zhou JJ, Zhu Y, Kosten T, Li DP. Chronic Unpredictable Mild Stress Induces Loss of GABA Inhibition in Corticotrophin-Releasing Hormone-Expressing Neurons through NKCC1 Upregulation. Neuroendocrinology 2017; 104:194-208. [PMID: 27077366 PMCID: PMC5065755 DOI: 10.1159/000446114] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 04/12/2016] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Prolonged and repeated stresses cause hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. The corticotrophin-releasing hormone (CRH)-expressing neurons in the hypothalamic paraventricular nucleus (PVN) are an essential component of the HPA axis. MATERIALS AND METHODS Chronic unpredictable mild stress (CUMS) was induced in Sprague-Dawley rats. GABA reversal potentials (EGABA) were determined by using gramicidin-perforated recordings in identified PVN-CRH neurons through expressing enhanced green fluorescent protein driven by the CRH promoter. Plasma corticosterone (CORT) levels were measured in rats implanted with a cannula targeting the lateral ventricles and PVN. RESULTS Blocking the GABAA receptor in the PVN with gabazine significantly increased plasma CORT levels in unstressed rats but did not change CORT levels in CUMS rats. CUMS caused a depolarizing shift in EGABA in PVN-CRH neurons compared with EGABA in PVN-CRH neurons in unstressed rats. Furthermore, CUMS induced a long-lasting increase in expression levels of the cation chloride cotransporter Na+-K+-Cl--Cl- (NKCC1) in the PVN but a transient decrease in expression levels of K+-Cl--Cl- in the PVN, which returned to the basal level 5 days after CUMS treatment. The NKCC1 inhibitor bumetanide decreased the basal firing activity of PVN-CRH neurons and normalized EGABA and the gabazine-induced excitatory effect on PVN-CRH neurons in CUMS rats. In addition, central administration of bumetanide decreased basal circulating CORT levels in CUMS rats. CONCLUSIONS These data suggest that chronic stress impairs GABAergic inhibition, resulting in HPA axis hyperactivity through upregulation of NKCC1.
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Affiliation(s)
- Yonggang Gao
- Department of Anesthesiology & Perioperative Medicine, The University of Texas MD Anderson Cancer Center
| | - Jing-Jing Zhou
- Department of Anesthesiology & Perioperative Medicine, The University of Texas MD Anderson Cancer Center
| | - Yun Zhu
- Department of Anesthesiology & Perioperative Medicine, The University of Texas MD Anderson Cancer Center
| | | | - De-Pei Li
- Department of Critical Care, The University of Texas MD Anderson Cancer Center
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41
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Abstract
The posterior pituitary gland secretes oxytocin and vasopressin (the antidiuretic hormone) into the blood system. Oxytocin is required for normal delivery of the young and for delivery of milk to the young during lactation. Vasopressin increases water reabsorption in the kidney to maintain body fluid balance and causes vasoconstriction to increase blood pressure. Oxytocin and vasopressin secretion occurs from the axon terminals of magnocellular neurons whose cell bodies are principally found in the hypothalamic supraoptic nucleus and paraventricular nucleus. The physiological functions of oxytocin and vasopressin depend on their secretion, which is principally determined by the pattern of action potentials initiated at the cell bodies. Appropriate secretion of oxytocin and vasopressin to meet the challenges of changing physiological conditions relies mainly on integration of afferent information on reproductive, osmotic, and cardiovascular status with local regulation of magnocellular neurons by glia as well as intrinsic regulation by the magnocellular neurons themselves. This review focuses on the control of magnocellular neuron activity with a particular emphasis on their regulation by reproductive function, body fluid balance, and cardiovascular status. © 2016 American Physiological Society. Compr Physiol 6:1701-1741, 2016.
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Affiliation(s)
- Colin H Brown
- Brain Health Research Centre, Centre for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin, New Zealand
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42
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Choe KY, Trudel E, Bourque CW. Effects of Salt Loading on the Regulation of Rat Hypothalamic Magnocellular Neurosecretory Cells by Ionotropic GABA and Glycine Receptors. J Neuroendocrinol 2016; 28. [PMID: 26833894 DOI: 10.1111/jne.12372] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/12/2016] [Accepted: 01/23/2016] [Indexed: 12/18/2022]
Abstract
Synaptic and extrasynaptic transmission mediated by ionotropic GABA and glycine receptors plays a critical role in shaping the action potential firing (spiking) activity of hypothalamic magnocellular neurosecretory cells and therefore determines the rate at which vasopressin and oxytocin are released from the neurohypophysis. The inhibitory effect of these transmitters relies on the maintenance of a low concentration of intracellular chloride ions such that, when activated by GABA or glycine, a hyperpolarisation of the neuronal membrane potential results. In this review, we highlight the various ways by which the two types of inhibitory receptors contribute to homeostasis by fine-tuning the spiking rate of vasopressin-releasing magnocellular neurosecretory cells in a manner dependent on the hydration state of the animal. In addition, we review the currently available evidence on how the strength of these inhibitory pathways can be regulated during chronic hypernatraemia via a form of activity-dependent depolarisation of the chloride reversal potential, leading to an abolition of these inhibitory pathways potentially causing sodium-dependent elevations in blood pressure.
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Affiliation(s)
- K Y Choe
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - E Trudel
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - C W Bourque
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal, Canada
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43
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Han SY, Bouwer GT, Seymour AJ, Korpal AK, Schwenke DO, Brown CH. Induction of hypertension blunts baroreflex inhibition of vasopressin neurons in the rat. Eur J Neurosci 2015; 42:2690-8. [PMID: 26342194 DOI: 10.1111/ejn.13062] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 08/12/2015] [Accepted: 08/27/2015] [Indexed: 01/21/2023]
Abstract
Vasopressin secretion from the posterior pituitary gland is determined by action potential discharge of hypothalamic magnocellular neurosecretory cells. Vasopressin is a potent vasoconstrictor, but vasopressin levels are paradoxically elevated in some patients with established hypertension. To determine whether vasopressin neurons are excited in hypertension, extracellular single-unit recordings of vasopressin neurons from urethane-anaesthetized Cyp1a1-Ren2 rats with inducible angiotensin-dependent hypertension were made. The basal firing rate of vasopressin neurons was higher in hypertensive Cyp1a1-Ren2 rats than in non-hypertensive Cyp1a1-Ren2 rats. The increase in firing rate was specific to vasopressin neurons because oxytocin neuron firing rate was unaffected by the induction of hypertension. Intravenous injection of the α1-adrenoreceptor agonist, phenylephrine (2.5 μg/kg), transiently increased mean arterial blood pressure to cause a baroreflex-induced inhibition of heart rate and vasopressin neuron firing rate (by 52 ± 9%) in non-hypertensive rats. By contrast, intravenous phenylephrine did not inhibit vasopressin neurons in hypertensive rats, despite a similar increase in mean arterial blood pressure and inhibition of heart rate. Circulating angiotensin II can excite vasopressin neurons via activation of afferent inputs from the subfornical organ. However, the increase in vasopressin neuron firing rate and the loss of inhibition by intravenous phenylephrine were not blocked by intra-subfornical organ infusion of the angiotensin AT1 receptor antagonist, losartan. It can be concluded that increased vasopressin neuron activity at the onset of hypertension is driven, at least in part, by reduced baroreflex inhibition of vasopressin neurons and that this might exacerbate the increase in blood pressure at the onset of hypertension.
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Affiliation(s)
- Su Young Han
- Centre for Neuroendocrinology, University of Otago, Dunedin, 9054, New Zealand.,Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
| | - Gregory T Bouwer
- Centre for Neuroendocrinology, University of Otago, Dunedin, 9054, New Zealand.,Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
| | - Alexander J Seymour
- Centre for Neuroendocrinology, University of Otago, Dunedin, 9054, New Zealand.,Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
| | - Aaron K Korpal
- Centre for Neuroendocrinology, University of Otago, Dunedin, 9054, New Zealand.,Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
| | - Daryl O Schwenke
- Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
| | - Colin H Brown
- Centre for Neuroendocrinology, University of Otago, Dunedin, 9054, New Zealand.,Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
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44
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Watanabe M, Fukuda A. Development and regulation of chloride homeostasis in the central nervous system. Front Cell Neurosci 2015; 9:371. [PMID: 26441542 PMCID: PMC4585146 DOI: 10.3389/fncel.2015.00371] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/04/2015] [Indexed: 12/22/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the mature central nervous system (CNS). The developmental switch of GABAergic transmission from excitation to inhibition is induced by changes in Cl− gradients, which are generated by cation-Cl− co-transporters. An accumulation of Cl− by the Na+-K+-2Cl− co-transporter (NKCC1) increases the intracellular Cl− concentration ([Cl−]i) such that GABA depolarizes neuronal precursors and immature neurons. The subsequent ontogenetic switch, i.e., upregulation of the Cl−-extruder KCC2, which is a neuron-specific K+-Cl− co-transporter, with or without downregulation of NKCC1, results in low [Cl−]i levels and the hyperpolarizing action of GABA in mature neurons. Development of Cl− homeostasis depends on developmental changes in NKCC1 and KCC2 expression. Generally, developmental shifts (decreases) in [Cl−]i parallel the maturation of the nervous system, e.g., early in the spinal cord, hypothalamus and thalamus, followed by the limbic system, and last in the neocortex. There are several regulators of KCC2 and/or NKCC1 expression, including brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF), and cystic fibrosis transmembrane conductance regulator (CFTR). Therefore, regionally different expression of these regulators may also contribute to the regional developmental shifts of Cl− homeostasis. KCC2 and NKCC1 functions are also regulated by phosphorylation by enzymes such as PKC, Src-family tyrosine kinases, and WNK1–4 and their downstream effectors STE20/SPS1-related proline/alanine-rich kinase (SPAK)-oxidative stress responsive kinase-1 (OSR1). In addition, activation of these kinases is modulated by humoral factors such as estrogen and taurine. Because these transporters use the electrochemical driving force of Na+ and K+ ions, topographical interaction with the Na+-K+ ATPase and its modulators such as creatine kinase (CK) should modulate functions of Cl− transporters. Therefore, regional developmental regulation of these regulators and modulators of Cl− transporters may also play a pivotal role in the development of Cl− homeostasis.
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Affiliation(s)
- Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
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45
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Ben-Ari Y. Is birth a critical period in the pathogenesis of autism spectrum disorders? Nat Rev Neurosci 2015; 16:498-505. [DOI: 10.1038/nrn3956] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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46
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Abstract
The Na-K-2Cl cotransporter 2 (NKCC2) was thought to be kidney specific. Here we show expression in the brain hypothalamo-neurohypophyseal system (HNS), wherein upregulation follows osmotic stress. The HNS controls osmotic stability through the synthesis and release of the neuropeptide hormone, arginine vasopressin (AVP). AVP travels through the bloodstream to the kidney, where it promotes water conservation. Knockdown of HNS NKCC2 elicited profound effects on fluid balance following ingestion of a high-salt solution-rats produced significantly more urine, concomitant with increases in fluid intake and plasma osmolality. Since NKCC2 is the molecular target of the loop diuretics bumetanide and furosemide, we asked about their effects on HNS function following disturbed water balance. Dehydration-evoked GABA-mediated excitation of AVP neurons was reversed by bumetanide, and furosemide blocked AVP release, both in vivo and in hypothalamic explants. Thus, NKCC2-dependent brain mechanisms that regulate osmotic stability are disrupted by loop diuretics in rats.
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47
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Lee SW, Kim YB, Kim JS, Kim WB, Kim YS, Han HC, Colwell CS, Cho YW, In Kim Y. GABAergic inhibition is weakened or converted into excitation in the oxytocin and vasopressin neurons of the lactating rat. Mol Brain 2015; 8:34. [PMID: 26017151 PMCID: PMC4446001 DOI: 10.1186/s13041-015-0123-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/12/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Increased secretion of oxytocin and arginine vasopressin (AVP) from hypothalamic magnocellular neurosecretory cells (MNCs) is a key physiological response to lactation. In the current study, we sought to test the hypothesis that the GABAA receptor-mediated inhibition of MNCs is altered in lactating rats. RESULTS Gramicidin-perforated recordings in the rat supraoptic nucleus (SON) slices revealed that the reversal potential of GABAA receptor-mediated response (EGABA) of MNCs was significantly depolarized in the lactating rats as compared to virgin animals. The depolarizing EGABA shift was much larger in rats in third, than first, lactation such that GABA exerted an excitatory, instead of inhibitory, effect in most of the MNCs of these multiparous rats. Immunohistochemical analyses confirmed that GABAergic excitation was found in both AVP and oxytocin neurons within the MNC population. Pharmacological experiments indicated that the up-regulation of the Cl(-) importer Na(+)-K(+)-2Cl(-) cotransporter isotype 1 and the down-regulation of the Cl(-) extruder K(+)-Cl(-) cotransporter isotype 2 were responsible for the depolarizing shift of EGABA and the resultant emergence of GABAergic excitation in the MNCs of the multiparous rats. CONCLUSION We conclude that, in primiparous rats, the GABAergic inhibition of MNCs is weakened during the period of lactation while, in multiparous females, GABA becomes excitatory in a majority of the cells. This reproductive experience-dependent alteration of GABAergic transmission may help to increase the secretion of oxytocin and AVP during the period of lactation.
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Affiliation(s)
- Seung Won Lee
- Department of Physiology, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul, 136-705, Republic of Korea.
| | - Young-Beom Kim
- Department of Physiology, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul, 136-705, Republic of Korea.
| | - Jeong Sook Kim
- Department of Physiology, Biomedical Science Institute & Medical Research Center, School of Medicine, Kyung Hee University, Seoul, 130-701, Republic of Korea.
| | - Woong Bin Kim
- Department of Physiology, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul, 136-705, Republic of Korea.
| | - Yoon Sik Kim
- Department of Physiology, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul, 136-705, Republic of Korea.
| | - Hee Chul Han
- Department of Physiology, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul, 136-705, Republic of Korea.
- Neuroscience Research Institute, Korea University College of Medicine, Seoul, 136-705, Republic of Korea.
| | - Christopher S Colwell
- Department of Psychiatry & Biobehavioral Sciences, University of California-Los Angeles, Los Angeles, CA, 90024, USA.
| | - Young-Wuk Cho
- Department of Physiology, Biomedical Science Institute & Medical Research Center, School of Medicine, Kyung Hee University, Seoul, 130-701, Republic of Korea.
| | - Yang In Kim
- Department of Physiology, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul, 136-705, Republic of Korea.
- Neuroscience Research Institute, Korea University College of Medicine, Seoul, 136-705, Republic of Korea.
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48
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Abstract
In a recent publication in Neuron, Choe et al. (2015) demonstrate that brain-derived neurotrophic factor (BDNF) signaling mediates salt-induced blood pressure elevation by increasing the excitability of hypothalamic vasopressin-secreting neurons. These findings suggest complex roles for BDNF in adaptive cardiovascular responses to physiological challenges and in the pathogenesis of hypertension.
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Affiliation(s)
- Krisztina Marosi
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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49
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Pallud J, Le Van Quyen M, Bielle F, Pellegrino C, Varlet P, Cresto N, Baulac M, Duyckaerts C, Kourdougli N, Chazal G, Devaux B, Rivera C, Miles R, Capelle L, Huberfeld G. Cortical GABAergic excitation contributes to epileptic activities around human glioma. Sci Transl Med 2015; 6:244ra89. [PMID: 25009229 DOI: 10.1126/scitranslmed.3008065] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Brain gliomas are highly epileptogenic. Excitatory glutamatergic mechanisms are involved in the generation of epileptic activities in the neocortex surrounding gliomas. However, chloride homeostasis is known to be perturbed in glioma cells. Thus, the contribution of γ-aminobutyric acidergic (GABAergic) mechanisms that depend on intracellular chloride merits closer study. We studied the occurrence, networks, cells, and signaling basis of epileptic activities in neocortical slices from the peritumoral surgical margin resected around human brain gliomas. Postoperative glioma tissue from 69% of patients spontaneously generated interictal-like discharges, synchronized, with a high-frequency oscillation signature, in superficial layers of neocortex around areas of glioma infiltration. Interictal-like events depended both on glutamatergic AMPA receptor-mediated transmission and on depolarizing GABAergic signaling. GABA released by interneurons depolarized 65% of pyramidal cells, in which chloride homeostasis was perturbed because of changes in expression of neuronal chloride cotransporters: KCC2 (K-Cl cotransporter 2) was reduced by 42% and expression of NKCC1 (Na-K-2Cl cotransporter 1) increased by 144%. Ictal-like activities were initiated by convulsant stimuli exclusively in these epileptogenic areas. This study shows that epileptic activities are sustained by excitatory effects of GABA in human peritumoral neocortex, as reported in temporal lobe epilepsies, suggesting that both glutamate and GABA signaling and cellular chloride regulation processes, all also involved in oncogenesis as already shown, induce an imbalance between synaptic excitation and inhibition underlying epileptic discharges in glioma patients. Thus, the control of chloride in neurons and glioma cells may provide a therapeutic target for patients with epileptogenic gliomas.
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Affiliation(s)
- Johan Pallud
- Institut du Cerveau et de la Moelle Epinière, INSERM UMRS975, CNRS UMR7225, Université Pierre et Marie Curie (UPMC), Paris, France.,Service de Neurochirurgie, Centre Hospitalier Sainte-Anne, Paris, France.,Université Paris Descartes, France
| | - Michel Le Van Quyen
- Institut du Cerveau et de la Moelle Epinière, INSERM UMRS975, CNRS UMR7225, Université Pierre et Marie Curie (UPMC), Paris, France
| | - Franck Bielle
- Service de Neuropathologie, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France
| | - Christophe Pellegrino
- INMED, Parc Scientifique de Luminy, Marseille, France.,Université de la Méditerranée, UMR S901 Aix-Marseille Université, Marseille, France
| | - Pascale Varlet
- Service de Neuropathologie, Centre Hospitalier Sainte-Anne, Paris, France
| | - Noemie Cresto
- Institut du Cerveau et de la Moelle Epinière, INSERM UMRS975, CNRS UMR7225, Université Pierre et Marie Curie (UPMC), Paris, France
| | - Michel Baulac
- Institut du Cerveau et de la Moelle Epinière, INSERM UMRS975, CNRS UMR7225, Université Pierre et Marie Curie (UPMC), Paris, France.,Unité d'Epileptologie, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France
| | - Charles Duyckaerts
- Service de Neuropathologie, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France
| | - Nazim Kourdougli
- INMED, Parc Scientifique de Luminy, Marseille, France.,Université de la Méditerranée, UMR S901 Aix-Marseille Université, Marseille, France
| | - Geneviève Chazal
- INMED, Parc Scientifique de Luminy, Marseille, France.,Université de la Méditerranée, UMR S901 Aix-Marseille Université, Marseille, France
| | - Bertrand Devaux
- Service de Neurochirurgie, Centre Hospitalier Sainte-Anne, Paris, France.,Université Paris Descartes, France
| | - Claudio Rivera
- INMED, Parc Scientifique de Luminy, Marseille, France.,Université de la Méditerranée, UMR S901 Aix-Marseille Université, Marseille, France.,Neuroscience Center, University of Helsinki, Finland
| | - Richard Miles
- Institut du Cerveau et de la Moelle Epinière, INSERM UMRS975, CNRS UMR7225, Université Pierre et Marie Curie (UPMC), Paris, France
| | - Laurent Capelle
- Institut du Cerveau et de la Moelle Epinière, INSERM UMRS975, CNRS UMR7225, Université Pierre et Marie Curie (UPMC), Paris, France.,Service de Neurochirurgie, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France
| | - Gilles Huberfeld
- Institut du Cerveau et de la Moelle Epinière, INSERM UMRS975, CNRS UMR7225, Université Pierre et Marie Curie (UPMC), Paris, France.,Service de Neuropathologie, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France.,Unité d'Epileptologie, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France.,Département de Neurophysiologie, UPMC, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France
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50
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Choe KY, Han SY, Gaub P, Shell B, Voisin DL, Knapp BA, Barker PA, Brown CH, Cunningham JT, Bourque CW. High salt intake increases blood pressure via BDNF-mediated downregulation of KCC2 and impaired baroreflex inhibition of vasopressin neurons. Neuron 2015; 85:549-60. [PMID: 25619659 PMCID: PMC4577058 DOI: 10.1016/j.neuron.2014.12.048] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 11/10/2014] [Accepted: 12/17/2014] [Indexed: 01/03/2023]
Abstract
The mechanisms by which dietary salt promotes hypertension are unknown. Previous work established that plasma [Na(+)] and osmolality rise in proportion with salt intake and thus promote release of vasopressin (VP) from the neurohypophysis. Although high levels of circulating VP can increase blood pressure, this effect is normally prevented by a potent GABAergic inhibition of VP neurons by aortic baroreceptors. Here we show that chronic high salt intake impairs baroreceptor inhibition of rat VP neurons through a brain-derived neurotrophic factor (BDNF)-dependent activation of TrkB receptors and downregulation of KCC2 expression, which prevents inhibitory GABAergic signaling. We show that high salt intake increases the spontaneous firing rate of VP neurons in vivo and that circulating VP contributes significantly to the elevation of arterial pressure under these conditions. These results provide the first demonstration that dietary salt can affect blood pressure through neurotrophin-induced plasticity in a central homeostatic circuit.
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Affiliation(s)
- Katrina Y Choe
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada
| | - Su Y Han
- Centre for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin 9054, New Zealand
| | - Perrine Gaub
- Montreal Neurological Institute, 3801 University Street, Montreal, QC H3A2B4, Canada
| | - Brent Shell
- Department of Integrative Physiology, University of North Texas Health Sciences Centre, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Daniel L Voisin
- Neurocentre Magendie, INSERM U862, 146, rue Léo Saignat, 33077 Bordeaux, France
| | - Blayne A Knapp
- Department of Integrative Physiology, University of North Texas Health Sciences Centre, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Philip A Barker
- Montreal Neurological Institute, 3801 University Street, Montreal, QC H3A2B4, Canada
| | - Colin H Brown
- Centre for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin 9054, New Zealand
| | - J Thomas Cunningham
- Department of Integrative Physiology, University of North Texas Health Sciences Centre, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Charles W Bourque
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, 1650 Cedar Avenue, Montreal, QC H3G1A4, Canada.
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