1
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Monroe SC, Radke AK. Opioid withdrawal: role in addiction and neural mechanisms. Psychopharmacology (Berl) 2023; 240:1417-1433. [PMID: 37162529 DOI: 10.1007/s00213-023-06370-2] [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: 10/03/2022] [Accepted: 04/19/2023] [Indexed: 05/11/2023]
Abstract
Withdrawal from opioids involves a negative affective state that promotes maintenance of drug-seeking behavior and relapse. As such, understanding the neurobiological mechanisms underlying withdrawal from opioid drugs is critical as scientists and clinicians seek to develop new treatments and therapies. In this review, we focus on the neural systems known to mediate the affective and somatic signs and symptoms of opioid withdrawal, including the mesolimbic dopaminergic system, basolateral amygdala, extended amygdala, and brain and hormonal stress systems. Evidence from preclinical studies suggests that these systems are altered following opioid exposure and that these changes mediate behavioral signs of negative affect such as aversion and anxiety during withdrawal. Adaptations in these systems also parallel the behavioral and psychological features of opioid use disorder (OUD), highlighting the important role of withdrawal in the development of addictive behavior. Implications for relapse and treatment are discussed as well as promising avenues for future research, with the hope of promoting continued progress toward characterizing neural contributors to opioid withdrawal and compulsive opioid use.
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Affiliation(s)
- Sean C Monroe
- Department of Psychology and Center for Neuroscience and Behavior, Miami University, 90 N Patterson Ave, Oxford, OH, USA
| | - Anna K Radke
- Department of Psychology and Center for Neuroscience and Behavior, Miami University, 90 N Patterson Ave, Oxford, OH, USA.
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2
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Jiao L, Wang Y, Zhang S, Wang Y, Liu Z, Liu Z, Zhou Y, Zhou H, Xu X, Li Z, Liu Z, Yu Z, Nie L, Zhou L, Jiang H. Melatonin improves cardiac remodeling and brain-heart sympathetic hyperactivation aggravated by light disruption after myocardial infarction. J Pineal Res 2022; 73:e12829. [PMID: 36031757 DOI: 10.1111/jpi.12829] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 08/11/2022] [Accepted: 08/24/2022] [Indexed: 11/27/2022]
Abstract
Light in the external environment might affect cardiovascular function. The light disruption seems to be related to changes in cardiovascular physiological functions, and disturbing light may be a risk factor for cardiovascular diseases. Prior studies have found that light disruption after myocardial infarction (MI) exacerbates cardiac remodeling, and the brain-heart sympathetic nervous system may be one of the key mechanisms. However, how to improve light-disrupted cardiac remodeling remains unclear. Melatonin is an indoleamine secreted by the pineal gland and controlled by endogenous circadian oscillators within the suprachiasmatic nucleus, which is closely associated with light/dark cycle. This study aimed to explore whether melatonin could improve light-disrupted cardiac remodeling and modulate the brain-heart sympathetic nervous system. Our study revealed that light disruption reduced serum melatonin levels, aggravated cardiac sympathetic remodeling, caused overactivation of the brain-heart sympathetic nervous system, exacerbated cardiac dysfunction, and increased cardiac fibrosis after MI, while melatonin treatment improved light disruption-exacerbated cardiac remodeling and brain-heart sympathetic hyperactivation after MI. Furthermore, RNA-Seq results revealed the significant changes at the cardiac transcription level. In conclusion, melatonin may be a potential therapy for light-disrupted cardiac remodeling.
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Affiliation(s)
- Liying Jiao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Yuhong Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Song Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Yueyi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Zhihao Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Zihan Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Yuyang Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Huixin Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Xiao Xu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Zeyan Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Zhihao Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Zhongyang Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Liqing Nie
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Liping Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Hong Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- Cardiac Autonomic Nervous System Research Center of Wuhan University, Wuhan, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
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3
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Grassi D, Marraudino M, Garcia-Segura LM, Panzica GC. The hypothalamic paraventricular nucleus as a central hub for the estrogenic modulation of neuroendocrine function and behavior. Front Neuroendocrinol 2022; 65:100974. [PMID: 34995643 DOI: 10.1016/j.yfrne.2021.100974] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 12/17/2022]
Abstract
Estradiol and hypothalamic paraventricular nucleus (PVN) help coordinate reproduction with body physiology, growth and metabolism. PVN integrates hormonal and neural signals originating in the periphery, generating an output mediated both by its long-distance neuronal projections, and by a variety of neurohormones produced by its magnocellular and parvocellular neurosecretory cells. Here we review the cyto-and chemo-architecture, the connectivity and function of PVN and the sex-specific regulation exerted by estradiol on PVN neurons and on the expression of neurotransmitters, neuromodulators, neuropeptides and neurohormones in PVN. Classical and non-classical estrogen receptors (ERs) are expressed in neuronal afferents to PVN and in specific PVN interneurons, projecting neurons, neurosecretory neurons and glial cells that are involved in the input-output integration and coordination of neurohormonal signals. Indeed, PVN ERs are known to modulate body homeostatic processes such as autonomic functions, stress response, reproduction, and metabolic control. Finally, the functional implications of the estrogenic modulation of the PVN for body homeostasis are discussed.
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Affiliation(s)
- D Grassi
- Department of Anatomy, Histology and Neuroscience, Universidad Autonoma de Madrid, Madrid, Spain
| | - M Marraudino
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Torino, Italy
| | - L M Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - G C Panzica
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Torino, Italy; Department of Neuroscience Rita Levi Montalcini, University of Torino, Torino, Italy.
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4
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Wang Y, Jiang W, Chen H, Zhou H, Liu Z, Liu Z, Liu Z, Zhou Y, Zhou X, Yu L, Jiang H. Sympathetic Nervous System Mediates Cardiac Remodeling After Myocardial Infarction in a Circadian Disruption Model. Front Cardiovasc Med 2021; 8:668387. [PMID: 33842566 PMCID: PMC8032890 DOI: 10.3389/fcvm.2021.668387] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/04/2021] [Indexed: 12/20/2022] Open
Abstract
Background: Circadian rhythms have a considerable impact on the daily physiology of the heart, and their disruption causes pathology. Several studies have revealed that circadian disruption impaired cardiac remodeling after myocardial infarction (MI); however, the underlying brain-heart mechanisms remain unknown. We aim to discuss whether circadian disruption facilitates cardiac remodeling after MI by activating sympathetic nervous system. Methods: Rats were randomly divided into three groups: Sham group (Sham), MI group (MI), and MI+ circadian disruption group (MI+Dis); rats were treated with pseudorabies virus (PRV) injections for trans-synaptic retrograde tracing; rats were randomly divided into two groups: MI+ circadian disruption + Empty Vector+ clozapine N-oxide (CNO) (Empty Vector), and MI+ circadian disruption + hM4D(Gi)+ CNO [hM4D(Gi)]. Results: Circadian disruption significantly facilitated cardiac remodeling after MI with lower systolic function, larger left ventricular volume, and aggravated cardiac fibrosis. Cardiac sympathetic remodeling makers and serum norepinephrine levels were also significantly increased by circadian disruption. PRV virus-labeled neurons were identified in the superior cervical ganglion (SCG), paraventricular nucleus (PVN), and suprachiasmatic nucleus (SCN) regions. Ganglionic blockade via designer receptors exclusively activated by designer drugs (DREADD) technique suppressed the activity of sympathetic nervous system and significantly alleviated the disruption-related cardiac dysfunction. Conclusion: Circadian disruption adversely affected cardiac remodeling after MI possibly by activating sympathetic nervous system, and suppressing sympathetic activity can attenuate this disruption-related cardiac dysfunction.
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Affiliation(s)
- Yuhong Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Wanli Jiang
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Hu Chen
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Huixin Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Zhihao Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Zihan Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Zhihao Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Yuyang Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Xiaoya Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Lilei Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Hong Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous Research Center, Wuhan University, Wuhan, China.,Department of Cardiology Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
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5
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Circadian circuits in humans: White matter microstructure predicts daytime sleepiness. Cortex 2019; 122:97-107. [PMID: 31097190 DOI: 10.1016/j.cortex.2019.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/31/2018] [Accepted: 01/14/2019] [Indexed: 11/22/2022]
Abstract
The suprachiasmatic nucleus of the hypothalamus is the chief circadian pacemaker in the brain, and is entrained to day-night cycles by visual afferents from melanopsin containing retinal ganglion cells via the inferior accessory optic tract. Tracer studies have demonstrated efferents from the suprachiasmatic nucleus projecting to the paraventricular nucleus of the hypothalamus, which in turn project to first-order sympathetic neurons in the intermedio-lateral grey of the spinal cord. Sympathetic projections to the pineal gland trigger the secretion of the sleep inducing hormone melatonin. The current study reports the first demonstration of potential sympathopetal hypothalamic projections involved in circadian regulation in humans with in vivo virtual white matter dissections using probabilistic diffusion tensor imaging (DTI) tractography. Additionally, our data shows a correlation between individual differences in white matter microstructure (measured with fractional anisotropy) and increased daytime sleepiness [measured with the Epworth Sleepiness Scale (ESS, Johns, 1991)]. Sympathopetal connections with the hypothalamus were virtually dissected using designated masks on the optic chiasm, which served as an anatomical landmark for retinal fibres projecting to the suprachiasmatic nucleus, and a waypoint mask on the lateral medulla, where hypothalamic projections to the sympathetic nervous system traverse in humans. Sympathopetal projections were demonstrated in each hemisphere in twenty-six subjects. The tract passed through the suprachiasmatic nucleus of the hypothalamus and its trajectory corresponds to the dorsal longitudinal fasciculus traversing the periaqueductal region and the lateral medulla. White matter microstructure (FA) in the left hemisphere correlated with high scores on the ESS, suggesting an association between circadian pathway white matter microstructure, and increased daytime sleepiness.
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6
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Feetham CH, O'Brien F, Barrett-Jolley R. Ion Channels in the Paraventricular Hypothalamic Nucleus (PVN); Emerging Diversity and Functional Roles. Front Physiol 2018; 9:760. [PMID: 30034342 PMCID: PMC6043726 DOI: 10.3389/fphys.2018.00760] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022] Open
Abstract
The paraventricular nucleus of the hypothalamus (PVN) is critical for the regulation of homeostatic function. Although also important for endocrine regulation, it has been referred to as the "autonomic master controller." The emerging consensus is that the PVN is a multifunctional nucleus, with autonomic roles including (but not limited to) coordination of cardiovascular, thermoregulatory, metabolic, circadian and stress responses. However, the cellular mechanisms underlying these multifunctional roles remain poorly understood. Neurones from the PVN project to and can alter the function of sympathetic control regions in the medulla and spinal cord. Dysfunction of sympathetic pre-autonomic neurones (typically hyperactivity) is linked to several diseases including hypertension and heart failure and targeting this region with specific pharmacological or biological agents is a promising area of medical research. However, to facilitate future medical exploitation of the PVN, more detailed models of its neuronal control are required; populated by a greater compliment of constituent ion channels. Whilst the cytoarchitecture, projections and neurotransmitters present in the PVN are reasonably well documented, there have been fewer studies on the expression and interplay of ion channels. In this review we bring together an up to date analysis of PVN ion channel studies and discuss how these channels may interact to control, in particular, the activity of the sympathetic system.
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Affiliation(s)
- Claire H Feetham
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Fiona O'Brien
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Richard Barrett-Jolley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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7
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Dergacheva O, Mendelowitz D. Combined hypoxia and hypercapnia, but not hypoxia alone, suppresses neurotransmission from orexin to hypothalamic paraventricular spinally-projecting neurons in weanling rats. Brain Res 2017; 1679:33-38. [PMID: 29162453 DOI: 10.1016/j.brainres.2017.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/03/2017] [Accepted: 11/16/2017] [Indexed: 12/30/2022]
Abstract
Both orexin neurons in the lateral hypothalamus and spinally-projecting pre-sympathetic neurons (PSNs) in the paraventricular nucleus of the hypothalamus (PVN) play an important role in the regulation of cardiovascular function under normal conditions and during cardiovascular challenges such as hypoxia and/or hypercapnia. We have previously established, using selective optogenetic excitation of orexin neurons and pathways, there is a heterogeneous neurotransmission from orexin neurons to PSNs in the PVN. This study was undertaken to test whether this pathway is altered by acute exposure to hypoxia alone and/or combined hypoxia and hypercapnia (H/H). To test this hypothesis, we selectively expressed channelrhodopsin-2 (ChR2) in orexin neurons in the lateral hypothalamus and photoactivated ChR2-expressing fibers to evoke postsynaptic currents in spinally-projecting PSNs in an in vitro slice preparation in rats. In accordance with previously published data, two subpopulations of spinally-projecting PSNs were established, including those with glutamatergic or GABAergic inputs from orexin neurons. Hypoxia alone did not alter the peak amplitude of either glutamatergic or GABAergic neurotransmission, however, H/H significantly inhibited both glutamatergic and GABAergic neurotransmission from orexin neurons to SPNs. In conclusion, H/H may modulate cardiovascular function by affecting heterogeneous pathways from orexin neurons to spinally-projecting PSNs in the PVN.
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Affiliation(s)
- Olga Dergacheva
- *Department of Pharmacology and Physiology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA.
| | - David Mendelowitz
- *Department of Pharmacology and Physiology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA
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8
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Bassi GS, Dias DPM, Franchin M, Talbot J, Reis DG, Menezes GB, Castania JA, Garcia-Cairasco N, Resstel LBM, Salgado HC, Cunha FQ, Cunha TM, Ulloa L, Kanashiro A. Modulation of experimental arthritis by vagal sensory and central brain stimulation. Brain Behav Immun 2017; 64:330-343. [PMID: 28392428 PMCID: PMC6330674 DOI: 10.1016/j.bbi.2017.04.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/25/2017] [Accepted: 04/04/2017] [Indexed: 12/20/2022] Open
Abstract
Articular inflammation is a major clinical burden in multiple inflammatory diseases, especially in rheumatoid arthritis. Biological anti-rheumatic drug therapies are expensive and increase the risk of systemic immunosuppression, infections, and malignancies. Here, we report that vagus nerve stimulation controls arthritic joint inflammation by inducing local regulation of innate immune response. Most of the previous studies of neuromodulation focused on vagal regulation of inflammation via the efferent peripheral pathway toward the viscera. Here, we report that vagal stimulation modulates arthritic joint inflammation through a novel "afferent" pathway mediated by the locus coeruleus (LC) of the central nervous system. Afferent vagal stimulation activates two sympatho-excitatory brain areas: the paraventricular hypothalamic nucleus (PVN) and the LC. The integrity of the LC, but not that of the PVN, is critical for vagal control of arthritic joint inflammation. Afferent vagal stimulation suppresses articular inflammation in the ipsilateral, but not in the contralateral knee to the hemispheric LC lesion. Central stimulation is followed by subsequent activation of joint sympathetic nerve terminals inducing articular norepinephrine release. Selective adrenergic beta-blockers prevent the effects of articular norepinephrine and thereby abrogate vagal control of arthritic joint inflammation. These results reveals a novel neuro-immune brain map with afferent vagal signals controlling side-specific articular inflammation through specific inflammatory-processing brain centers and joint sympathetic innervations.
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Affiliation(s)
- Gabriel Shimizu Bassi
- Department of Immunology, Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, SP, Brazil.
| | | | - Marcelo Franchin
- Department of Pharmacology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Jhimmy Talbot
- Department of Pharmacology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Daniel Gustavo Reis
- Department of Pharmacology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Gustavo Batista Menezes
- Center for Gastrointestinal Biology, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Jaci Airton Castania
- Department of Physiology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Norberto Garcia-Cairasco
- Department of Physiology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Helio Cesar Salgado
- Department of Physiology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Fernando Queiró Cunha
- Department of Pharmacology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Thiago Mattar Cunha
- Department of Pharmacology, Ribeirão Preto Medical School – University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luis Ulloa
- Department of Surgery, Center of Immunology & Inflammation, Rutgers-New Jersey Medical School, Rutgers University, Newark, NJ 07101, USA.
| | - Alexandre Kanashiro
- Department of Pharmacology, Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, SP, Brazil; Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, Brazil.
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9
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Eldahan KC, Rabchevsky AG. Autonomic dysreflexia after spinal cord injury: Systemic pathophysiology and methods of management. Auton Neurosci 2017; 209:59-70. [PMID: 28506502 DOI: 10.1016/j.autneu.2017.05.002] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 03/30/2017] [Accepted: 05/03/2017] [Indexed: 12/11/2022]
Abstract
Traumatic spinal cord injury (SCI) has widespread physiological effects beyond the disruption of sensory and motor function, notably the loss of normal autonomic and cardiovascular control. Injury at or above the sixth thoracic spinal cord segment segregates critical spinal sympathetic neurons from supraspinal modulation which can result in a syndrome known as autonomic dysreflexia (AD). AD is defined as episodic hypertension and concomitant baroreflex-mediated bradycardia initiated by unmodulated sympathetic reflexes in the decentralized cord. This condition is often triggered by noxious yet unperceived visceral or somatic stimuli below the injury level and if severe enough can require immediate medical attention. Herein, we review the pathophysiological mechanisms germane to the development of AD, including maladaptive plasticity of neural circuits mediating abnormal sympathetic reflexes and hypersensitization of peripheral vasculature that collectively contribute to abnormal hemodynamics after SCI. Further, we discuss the systemic effects of recurrent AD and pharmacological treatments used to manage such episodes. Contemporary research avenues are then presented to better understand the relative contributions of underlying mechanisms and to elucidate the effects of recurring AD on cardiovascular and immune functions for developing more targeted and effective treatments to attenuate the development of this insidious syndrome following high-level SCI.
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Affiliation(s)
- Khalid C Eldahan
- Department of Physiology, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States
| | - Alexander G Rabchevsky
- Department of Physiology, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States.
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10
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Dergacheva O, Yamanaka A, Schwartz AR, Polotsky VY, Mendelowitz D. Optogenetic identification of hypothalamic orexin neuron projections to paraventricular spinally projecting neurons. Am J Physiol Heart Circ Physiol 2017; 312:H808-H817. [PMID: 28159808 DOI: 10.1152/ajpheart.00572.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 01/31/2017] [Accepted: 01/31/2017] [Indexed: 02/07/2023]
Abstract
Orexin neurons, and activation of orexin receptors, are generally thought to be sympathoexcitatory; however, the functional connectivity between orexin neurons and a likely sympathetic target, the hypothalamic spinally projecting neurons (SPNs) in the paraventricular nucleus of the hypothalamus (PVN) has not been established. To test the hypothesis that orexin neurons project directly to SPNs in the PVN, channelrhodopsin-2 (ChR2) was selectively expressed in orexin neurons to enable photoactivation of ChR2-expressing fibers while examining evoked postsynaptic currents in SPNs in rat hypothalamic slices. Selective photoactivation of orexin fibers elicited short-latency postsynaptic currents in all SPNs tested (n = 34). These light-triggered responses were heterogeneous, with a majority being excitatory glutamatergic responses (59%) and a minority of inhibitory GABAergic (35%) and mixed glutamatergic and GABAergic currents (6%). Both glutamatergic and GABAergic responses were present in the presence of tetrodotoxin and 4-aminopyridine, suggesting a monosynaptic connection between orexin neurons and SPNs. In addition to generating postsynaptic responses, photostimulation facilitated action potential firing in SPNs (current clamp configuration). Glutamatergic, but not GABAergic, postsynaptic currents were diminished by application of the orexin receptor antagonist almorexant, indicating orexin release facilitates glutamatergic neurotransmission in this pathway. This work identifies a neuronal circuit by which orexin neurons likely exert sympathoexcitatory control of cardiovascular function.NEW & NOTEWORTHY This is the first study to establish, using innovative optogenetic approaches in a transgenic rat model, that there are robust heterogeneous projections from orexin neurons to paraventricular spinally projecting neurons, including excitatory glutamatergic and inhibitory GABAergic neurotransmission. Endogenous orexin release modulates glutamatergic, but not GABAergic, neurotransmission in these pathways.
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Affiliation(s)
- Olga Dergacheva
- Department of Pharmacology and Physiology, The George Washington University, Washington, District of Columbia;
| | - Akihiro Yamanaka
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan; and
| | - Alan R Schwartz
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University, Washington, District of Columbia
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Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) associated with lateral medullary syndrome: case report and literature review. BMC Neurol 2016; 16:119. [PMID: 27461339 PMCID: PMC4962364 DOI: 10.1186/s12883-016-0641-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 07/20/2016] [Indexed: 11/26/2022] Open
Abstract
Background Only one case of syndrome of inappropriate secretion of antidiuretic hormone with lateral medullary syndrome has been reported so far. We report a case of lateral medullary syndrome showing syndrome of inappropriate secretion of antidiuretic hormone and analyze the pathomechanism underlying its clinical features. Case presentation A 67-year-old man was admitted to our hospital for dizziness, dysarthria, and dysphagia. He was diagnosed with lateral medullary syndrome based on the neurological examination and brain magnetic resonance imaging. Horner syndrome was absent. Asymptomatic hyponatremia appeared 9 days after admission and the patient was diagnosed with syndrome of inappropriate secretion of antidiuretic hormone. Fluid restriction and intravenous furosemide injection improved the hyponatremia. Conclusion Lateral medullary syndrome could be associated with syndrome of inappropriate secretion of antidiuretic hormone.
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El-Werfali W, Toomasian C, Maliszewska-Scislo M, Li C, Rossi NF. Haemodynamic and renal sympathetic responses to V1b vasopressin receptor activation within the paraventricular nucleus. Exp Physiol 2016; 100:553-65. [PMID: 25605313 DOI: 10.1113/expphysiol.2014.084426] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/16/2015] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does antagonism of V1b receptors prevent the haemodynamic and renal sympathetic nerve responses that occur with application of exogenous vasopressin into the paraventricular nucleus (PVN) of conscious, chronically instrumented rats? What is the main finding and its importance? Microinjection of vasopressin into the PVN increased mean arterial pressure, heart rate and renal sympathetic nerve activity, all of which were inhibited by pre-injection of the PVN with the V1b antagonist, nelivaptan. The administered vasopressin did not enter the peripheral circulation or increase plasma vasopressin. Ganglionic blockade prevented each of the responses, consistent with mediation by enhanced sympathetic output rather than an increase in circulating vasopressin. Vasopressin (VP) participates in regulation of haemodynamics and volume. Besides more classical actions as a circulating hormone, VP may act via release from axons and dendrites within the CNS. The paraventricular nucleus (PVN) possesses vasopressinergic neurons and a dense complement of VP receptors, including the V1b receptor, which has been implicated in several types of stress responses. We tested the hypothesis that antagonism of V1b receptors will prevent VP-induced increases in mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA). Studies were performed in conscious male Sprague-Dawley rats chronically instrumented with vascular catheters, renal nerve electrodes and a cannula stereotaxically directed into the PVN. Unilateral microinjection of VP into the PVN significantly increased MAP, HR and RSNA, peaking at 10 min. Pre-injection of the PVN with the selective V1b receptor antagonist, nelivaptan, did not alter baseline values but blocked the responses to VP. Ganglionic blockade with chlorisondamine decreased MAP and HR and abolished their increase in response to subsequent PVN application of VP. Injection of VP into the PVN did not alter plasma VP levels. Paraventricular nucleus injection with radiolabelled VP resulted in negligible radiolabelled VP in peripheral blood. These findings support the concept that, in basal conditions, PVN V1b receptor activation (rather than VP release into the periphery) may be implicated in the increases in MAP, HR and RSNA due to increased sympathetic outflow. While the role of V1a and oxytocin receptors cannot be excluded, these data suggest that further studies of the role of V1b receptor activation by endogenous VP during stress to effect neuroexcitation are warranted.
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Affiliation(s)
- Wafa El-Werfali
- Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI, USA; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
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Deuchars SA, Lall VK. Sympathetic preganglionic neurons: properties and inputs. Compr Physiol 2016; 5:829-69. [PMID: 25880515 DOI: 10.1002/cphy.c140020] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The sympathetic nervous system comprises one half of the autonomic nervous system and participates in maintaining homeostasis and enabling organisms to respond in an appropriate manner to perturbations in their environment, either internal or external. The sympathetic preganglionic neurons (SPNs) lie within the spinal cord and their axons traverse the ventral horn to exit in ventral roots where they form synapses onto postganglionic neurons. Thus, these neurons are the last point at which the central nervous system can exert an effect to enable changes in sympathetic outflow. This review considers the degree of complexity of sympathetic control occurring at the level of the spinal cord. The morphology and targets of SPNs illustrate the diversity within this group, as do their diverse intrinsic properties which reveal some functional significance of these properties. SPNs show high degrees of coupled activity, mediated through gap junctions, that enables rapid and coordinated responses; these gap junctions contribute to the rhythmic activity so critical to sympathetic outflow. The main inputs onto SPNs are considered; these comprise afferent, descending, and interneuronal influences that themselves enable functionally appropriate changes in SPN activity. The complexity of inputs is further demonstrated by the plethora of receptors that mediate the different responses in SPNs; their origins and effects are plentiful and diverse. Together these different inputs and the intrinsic and coupled activity of SPNs result in the rhythmic nature of sympathetic outflow from the spinal cord, which has a variety of frequencies that can be altered in different conditions.
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Affiliation(s)
- Susan A Deuchars
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
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Kumar Jha P, Challet E, Kalsbeek A. Circadian rhythms in glucose and lipid metabolism in nocturnal and diurnal mammals. Mol Cell Endocrinol 2015; 418 Pt 1:74-88. [PMID: 25662277 DOI: 10.1016/j.mce.2015.01.024] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/12/2015] [Accepted: 01/19/2015] [Indexed: 12/22/2022]
Abstract
Most aspects of energy metabolism display clear variations during day and night. This daily rhythmicity of metabolic functions, including hormone release, is governed by a circadian system that consists of the master clock in the suprachiasmatic nuclei of the hypothalamus (SCN) and many secondary clocks in the brain and peripheral organs. The SCN control peripheral timing via the autonomic and neuroendocrine system, as well as via behavioral outputs. The sleep-wake cycle, the feeding/fasting rhythm and most hormonal rhythms, including that of leptin, ghrelin and glucocorticoids, usually show an opposite phase (relative to the light-dark cycle) in diurnal and nocturnal species. By contrast, the SCN clock is most active at the same astronomical times in these two categories of mammals. Moreover, in both species, pineal melatonin is secreted only at night. In this review we describe the current knowledge on the regulation of glucose and lipid metabolism by central and peripheral clock mechanisms. Most experimental knowledge comes from studies in nocturnal laboratory rodents. Nevertheless, we will also mention some relevant findings in diurnal mammals, including humans. It will become clear that as a consequence of the tight connections between the circadian clock system and energy metabolism, circadian clock impairments (e.g., mutations or knock-out of clock genes) and circadian clock misalignments (such as during shift work and chronic jet-lag) have an adverse effect on energy metabolism, that may trigger or enhancing obese and diabetic symptoms.
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Affiliation(s)
- Pawan Kumar Jha
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; Regulation of Circadian Clocks Team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, France; International Associated Laboratory LIA1061 Understanding the Neural Basis of Diurnality, CNRS, France and the Netherlands
| | - Etienne Challet
- Regulation of Circadian Clocks Team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, France; International Associated Laboratory LIA1061 Understanding the Neural Basis of Diurnality, CNRS, France and the Netherlands
| | - Andries Kalsbeek
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; International Associated Laboratory LIA1061 Understanding the Neural Basis of Diurnality, CNRS, France and the Netherlands; Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, The Netherlands.
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Saderi N, Buijs F, Salgado-Delgado R, Merkenstein M, Basualdo M, Ferri GL, Escobar C, Buijs R. A role for VGF in the hypothalamic arcuate and paraventricular nuclei in the control of energy homeostasis. Neuroscience 2014; 265:184-95. [DOI: 10.1016/j.neuroscience.2014.01.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 10/25/2022]
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Handa RJ, Weiser MJ. Gonadal steroid hormones and the hypothalamo-pituitary-adrenal axis. Front Neuroendocrinol 2014; 35:197-220. [PMID: 24246855 PMCID: PMC5802971 DOI: 10.1016/j.yfrne.2013.11.001] [Citation(s) in RCA: 286] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 10/04/2013] [Accepted: 11/07/2013] [Indexed: 12/17/2022]
Abstract
The hypothalamo-pituitary-adrenal (HPA) axis represents a complex neuroendocrine feedback loop controlling the secretion of adrenal glucocorticoid hormones. Central to its function is the paraventricular nucleus of the hypothalamus (PVN) where neurons expressing corticotropin releasing factor reside. These HPA motor neurons are a primary site of integration leading to graded endocrine responses to physical and psychological stressors. An important regulatory factor that must be considered, prior to generating an appropriate response is the animal's reproductive status. Thus, PVN neurons express androgen and estrogen receptors and receive input from sites that also express these receptors. Consequently, changes in reproduction and gonadal steroid levels modulate the stress response and this underlies sex differences in HPA axis function. This review examines the make up of the HPA axis and hypothalamo-pituitary-gonadal (HPG) axis and the interactions between the two that should be considered when exploring normal and pathological responses to environmental stressors.
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Affiliation(s)
- Robert J Handa
- Department of Basic Medical Science, The University of Arizona College of Medicine, Phoenix, AZ 85004, United States.
| | - Michael J Weiser
- DSM Nutritional Products Ltd., R&D Human Nutrition and Health, Boulder, CO 80301, United States
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Dobberfuhl AD, Oti T, Sakamoto H, Marson L. Identification of CNS neurons innervating the levator ani and ventral bulbospongiosus muscles in male rats. J Sex Med 2013; 11:664-77. [PMID: 24373488 DOI: 10.1111/jsm.12418] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The pelvic striated muscles play an important role in mediating erections and ejaculation, and together these muscles compose a tightly coordinated neuromuscular system that is androgen sensitive and sexually dimorphic. AIM To identify spinal and brains neurons involved in the control of the levator ani (LA) and bulbospongiosus (BS) in the male adult and preadolescent rat. METHODS Rats were anesthetized, and the transsynaptic retrograde tracer pseudorabies virus (PRV) was injected into the LA muscle of adults or the ventral BS muscle in 30-day-old rats. After 3-5 days rats were sacrificed, and PRV-labeled neurons in the spinal cords and brains were identified using immunohistochemistry. The presence of gastrin-releasing peptide (GRP) in the lumbar spinal neurons was examined. MAIN OUTCOMES MEASURES The location and number of PRV-labeled neurons in the spinal cord and brain and GRP colocalization in the lumbar spinal cord. RESULTS PRV-labeled spinal interneurons were found distributed throughout T11-S1 of the spinal cord, subsequent to dorsal medial motoneuron infection. The majority of spinal interneurons were found in the lumbosacral spinal cord in the region of the dorsal gray commissure and parasympathetic preganglionic neurons. Preadolescent rats had more PRV-labeled spinal interneurons at L5-S1 where the motoneurons were located but relatively less spread rostrally in the spinal cord compared with adults. Lumbar spinothalmic neurons in medial gray of L3-L4 co-localized PRV and GRP. In the brain consistent labeling was seen in areas known to be involved in male sexual behavior including the ventrolateral medulla, hypothalamic paraventricular nucleus, and medial preoptic area. CONCLUSION Common spinal and brain pathways project to the LA and BS muscles in the rat suggesting that these muscles act together to coordinate male sexual reflexes. Differences may exist in the amount of synaptic connections/neuronal pathways in adolescents compared with adults.
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Affiliation(s)
- Amy D Dobberfuhl
- Division of Urology, Department of Surgery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Geraldes V, Gonçalves-Rosa N, Liu B, Paton JFR, Rocha I. Chronic depression of hypothalamic paraventricular neuronal activity produces sustained hypotension in hypertensive rats. Exp Physiol 2013; 99:89-100. [PMID: 24142454 DOI: 10.1113/expphysiol.2013.074823] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Changes in the sympathetic nervous system are responsible for the initiation, development and maintenance of hypertension. An important central sympathoexcitatory region is the paraventricular nucleus (PVN) of the hypothalamus, which may become more active in hypertensive conditions, as shown in acute studies previously. Our objective was to depress PVN neuronal activity chronically by the overexpression of an inwardly rectifying potassium channel (hKir2.1), while evaluating the consequences on blood pressure (BP) and its reflex regulation. In spontaneously hypertensive rats (SHRs) and Wistar rats (WKY) lentiviral vectors (LVV-hKir2.1; LV-TREtight-Kir-cIRES-GFP5 4 × 10(9) IU and LV-Syn-Eff-G4BS-Syn-Tetoff 6.2 × 10(9) IU in a ratio 1:4) were stereotaxically microinjected bilaterally into the PVN. Sham-treated SHRs and WKY received bilateral PVN microinjections of LVV-eGFP (LV-Syn-Eff-G4BS-Syn-Tetoff 6.2 × 10(9) IU and LV-TREtight-GFP 5.7 × 10(9) IU in a ratio 1:4). Blood pressure was monitored continuously by radio-telemetry and evaluated over 75 days. Baroreflex gain was evaluated using phenylephrine (25 μg ml(-1), i.v.), whereas lobeline (25 μg ml(-1), i.v.) was used to stimulate peripheral chemoreceptors. In SHRs but not normotensive WKY rats, LVV-hKir2.1 expression in the PVN produced time-dependent and significant decreases in systolic (from 158 ± 3 to 132 ± 6 mmHg; P < 0.05) and diastolic BP (from 135 ± 4 to 113 ± 5 mmHg; P < 0.05). The systolic BP low-frequency band was reduced (from 0.79 ± 0.13 to 0.42 ± 0.09 mmHg(2); P < 0.05), suggesting reduced sympathetic vasomotor tone. Baroreflex gain was increased and peripheral chemoreflex depressed after PVN microinjection of LVV-hKir2.1. We conclude that the PVN plays a major role in long-term control of BP and sympathetic nervous system activity in SHRs. This is associated with reductions in both peripheral chemosensitivity and respiratory-induced sympathetic modulation and an improvement in baroreflex sensitivity. Our results support the PVN as a powerful site to control BP in neurogenic hypertension.
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Affiliation(s)
- Vera Geraldes
- I. Rocha: Instituto de Fisiologia, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, 1649-028 Lisbon, Portugal.
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Abstract
The central noradrenergic neurone, like the peripheral sympathetic neurone, is characterized by a diffusely arborizing terminal axonal network. The central neurones aggregate in distinct brainstem nuclei, of which the locus coeruleus (LC) is the most prominent. LC neurones project widely to most areas of the neuraxis, where they mediate dual effects: neuronal excitation by α₁-adrenoceptors and inhibition by α₂-adrenoceptors. The LC plays an important role in physiological regulatory networks. In the sleep/arousal network the LC promotes wakefulness, via excitatory projections to the cerebral cortex and other wakefulness-promoting nuclei, and inhibitory projections to sleep-promoting nuclei. The LC, together with other pontine noradrenergic nuclei, modulates autonomic functions by excitatory projections to preganglionic sympathetic, and inhibitory projections to preganglionic parasympathetic neurones. The LC also modulates the acute effects of light on physiological functions ('photomodulation'): stimulation of arousal and sympathetic activity by light via the LC opposes the inhibitory effects of light mediated by the ventrolateral preoptic nucleus on arousal and by the paraventricular nucleus on sympathetic activity. Photostimulation of arousal by light via the LC may enable diurnal animals to function during daytime. LC neurones degenerate early and progressively in Parkinson's disease and Alzheimer's disease, leading to cognitive impairment, depression and sleep disturbance.
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Affiliation(s)
- Elemer Szabadi
- Division of Psychiatry, University of Nottingham, Nottingham, UK.
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Coulibaly AP, Gannon SM, Hawk K, Walsh BF, Isaacson LG. Transection of preganglionic axons leads to CNS neuronal plasticity followed by survival and target reinnervation. Auton Neurosci 2013; 179:49-59. [PMID: 23891533 DOI: 10.1016/j.autneu.2013.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/17/2013] [Accepted: 07/04/2013] [Indexed: 10/26/2022]
Abstract
The goals of the present study were to investigate the changes in sympathetic preganglionic neurons following transection of distal axons in the cervical sympathetic trunk (CST) that innervate the superior cervical ganglion (SCG) and to assess changes in the protein expression of brain derived neurotrophic factor (BDNF) and its receptor TrkB in the thoracic spinal cord. At 1 week, a significant decrease in soma volume and reduced soma expression of choline acetyltransferase (ChAT) in the intermediolateral cell column (IML) of T1 spinal cord were observed, with both ChAT-ir and non-immunoreactive neurons expressing the injury marker activating transcription factor 3. These changes were transient, and at later time points, ChAT expression and soma volume returned to control values and the number of ATF3 neurons declined. No evidence for cell loss or neuronal apoptosis was detected at any time point. Protein levels of BDNF and/or full length TrkB in the spinal cord were increased throughout the survival period. In the SCG, both ChAT-ir axons and ChAT protein remained decreased at 16 weeks, but were increased compared to the 10 week time point. These results suggest that though IML neurons show reduced ChAT expression and cell volume at 1 week following CST transection, at later time points, the neurons recovered and exhibited no significant signs of neurodegeneration. The alterations in BDNF and/or TrkB may have contributed to the survival of the IML neurons and the recovery of ChAT expression, as well as to the reinnervation of the SCG.
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Affiliation(s)
- Aminata P Coulibaly
- Center for Neuroscience and Behavior, Miami University, Oxford, OH 45056, United States; Graduate Program in Cell, Molecular, and Structural Biology, Miami University, Oxford, OH 45056, United States
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Chen CY, Chern RS, Liao MH, Chang YH, Hsu JYC, Chien CH. The Possible Neuronal Mechanism of Acupuncture: Morphological Evidence of the Neuronal Connection between Groin A-Shi Point and Uterus. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2013; 2013:429186. [PMID: 23533481 PMCID: PMC3603327 DOI: 10.1155/2013/429186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/25/2013] [Indexed: 11/17/2022]
Abstract
Somatovisceral reflex suggested that the somatic stimulation could affect visceral function like acupuncture which treats diseases by stimulating acupoints. The neuronal connection between somatic point and visceral organ was not clear. Uterine pain referred to the groin region has long been recognized clinically. Wesselmann, using neurogenic plasma extravasation method, showed that uterine pain was referred to the groin region through a neuronal mechanism (Wesselmann and Lai 1997). This connection could be considered through the somatovisceral reflex pathway. However, the relay center of this pathway is still not clearly identified. In the present study, bee venom was injected in the groin region to induce central Fos expression to map the sensory innervation of groin region. Pseudorabies virus (PrV), a transneuronal tracer, was injected in the uterus to identify the higher motor control of the uterus. Immunohistochemistry staining revealed the Fos expression and PrV-infected double-labeled neurons in the nucleus of solitary tract (NTS), the dorsal motor nucleus of vagus (DMX), and the paraventricular hypothalamic nucleus (PVN). These results suggest a somatoparasympathetic neuronal connection (groin-spinal dorsal horn-NTS/DMX-uterus) and a somatosympathetic neuronal connection (groin-spinal dorsal horn-NTS-PVN-uterus). These two neuronal connections could be the prerequisites to the neuronal basis of the somatovisceral reflex and also the neuronal mechanism of acupuncture.
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Affiliation(s)
- Chun-Yen Chen
- Department of Cell Biology and Anatomy, College of Medicine, National Cheng-Kung University, Tainan, Taiwan
| | - Rey-Shyong Chern
- Graduate Institute and Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, 1, Shuefu Road, Neipu, Pingtung 912, Taiwan
| | - Ming-Huei Liao
- Graduate Institute and Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, 1, Shuefu Road, Neipu, Pingtung 912, Taiwan
| | - Yung-Hsien Chang
- Graduate Institute of Chinese Medical Science, China Medical University, Taichung, Taiwan
| | - Jung-Yu C. Hsu
- Department of Cell Biology and Anatomy, College of Medicine, National Cheng-Kung University, Tainan, Taiwan
| | - Chi-Hsien Chien
- Graduate Institute and Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, 1, Shuefu Road, Neipu, Pingtung 912, Taiwan
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Reflex modulation of ovarian estradiol secretion by noxious mechanical stimulation of a hindpaw in anesthetized rats. Auton Neurosci 2012; 171:14-20. [DOI: 10.1016/j.autneu.2012.08.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 06/22/2012] [Accepted: 08/22/2012] [Indexed: 11/19/2022]
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Affleck VS, Coote JH, Pyner S. The projection and synaptic organisation of NTS afferent connections with presympathetic neurons, GABA and nNOS neurons in the paraventricular nucleus of the hypothalamus. Neuroscience 2012; 219:48-61. [PMID: 22698695 PMCID: PMC3409377 DOI: 10.1016/j.neuroscience.2012.05.070] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 05/02/2012] [Accepted: 05/07/2012] [Indexed: 01/17/2023]
Abstract
Elevated sympathetic nerve activity, strongly associated with cardiovascular disease, is partly generated from the presympathetic neurons of the paraventricular nucleus of the hypothalamus (PVN). The PVN-presympathetic neurons regulating cardiac and vasomotor sympathetic activity receive information about cardiovascular status from receptors in the heart and circulation. These receptors signal changes via afferent neurons terminating in the nucleus tractus solitarius (NTS), some of which may result in excitation or inhibition of PVN-presympathetic neurons. Understanding the anatomy and neurochemistry of NTS afferent connections within the PVN could provide important clues to the impairment in homeostasis cardiovascular control associated with disease. Transynaptic labelling has shown the presence of neuronal nitric oxide synthase (nNOS)-containing neurons and GABA interneurons that terminate on presympathetic PVN neurons any of which may be the target for NTS afferents. So far NTS connections to these diverse neuronal pools have not been demonstrated and were investigated in this study. Anterograde (biotin dextran amine – BDA) labelling of the ascending projection from the NTS and retrograde (fluorogold – FG or cholera toxin B subunit – CTB) labelling of PVN presympathetic neurons combined with immunohistochemistry for GABA and nNOS was used to identify the terminal neuronal targets of the ascending projection from the NTS. It was shown that NTS afferent terminals are apposed to either PVN-GABA interneurons or to nitric oxide producing neurons or even directly to presympathetic neurons. Furthermore, there was evidence that some NTS axons were positive for vesicular glutamate transporter 2 (vGLUT2). The data provide an anatomical basis for the different functions of cardiovascular receptors that mediate their actions via the NTS–PVN pathways.
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Affiliation(s)
- V S Affleck
- School of Biological & Biomedical Sciences, Durham University, Durham DH1 3LE, UK
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Coulibaly AP, Isaacson LG. Transient changes in spinal cord glial cells following transection of preganglionic sympathetic axons. Auton Neurosci 2012; 168:32-42. [PMID: 22289358 PMCID: PMC3321080 DOI: 10.1016/j.autneu.2012.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 01/06/2012] [Accepted: 01/09/2012] [Indexed: 11/26/2022]
Abstract
Following peripheral nerve injury, retrograde signals originating from the injury site may activate intrinsic factors in the injured neurons, possibly leading to regenerative growth. Retrograde influences from peripheral injury sites may lead to the activation of glial cells in the vicinity of the centrally located cell bodies of the injured neurons. Few studies have examined changes in the spinal cord intermediolateral cell column (IML), which houses sympathetic preganglionic cell bodies, following injury to distal axons in the cervical sympathetic trunk (CST). The goal of the present study was to determine if transection of the CST results in plasticity in glial cells in the IML. At 1 day following injury, changes in the expression of microglial marker Iba1 were observed and the typical oligodendrocyte-neuronal relationship was altered. By 7 days, astrogliosis, microglial aggregation, and increased numbers of oligodendrocytes, as well as enhanced glial-glial and glial-neuronal relationships were present. The majority of cases were similar to controls at 3 weeks following injury and no changes were observed in any cases at 10 weeks following the injury. These results revealed changes in astrocytes, microglia, oligodendrocytes in the spinal cord following transection of preganglionic axons comprising the CST, indicating their ability to respond to distal axonal injury.
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Affiliation(s)
- Aminata P. Coulibaly
- Center for Neuroscience and Behavior, Department of Zoology, Miami University, Oxford, OH 45056
| | - Lori G. Isaacson
- Center for Neuroscience and Behavior, Department of Zoology, Miami University, Oxford, OH 45056
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25
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Ma Z, Liu T. Myricetin facilitates potassium currents and inhibits neuronal activity of PVN neurons. Neurochem Res 2012; 37:1450-6. [PMID: 22382814 DOI: 10.1007/s11064-012-0732-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 02/01/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
Abstract
The effects of myricetin on hypothalamic paraventricular nucleus (PVN) neurons in rats were investigated. By whole-cell patch clamp detection in hypothalamic brain slices, we showed that the action potential frequency in type-I PVN neurons dose-dependently decreased after myricetin treatment. Further studies demonstrated that myricetin may enhance potassium currents and shifts the voltage-dependence of activation of potassium currents to more negative potentials by 6.07 mV. Using calcium free/cadmium perfusion solution could reverse myricetin-induced enhancement of potassium currents in PVN neurons. These results suggested that inhibition of hypothalamic PVN neurons by myricetin might be attributed to the enhancement of potassium currents.
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Affiliation(s)
- ZeGang Ma
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China.
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26
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Teruyama R, Sakuraba M, Wilson LL, Wandrey NEJ, Armstrong WE. Epithelial Na⁺ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei. Am J Physiol Endocrinol Metab 2012; 302:E273-85. [PMID: 22045317 PMCID: PMC3287361 DOI: 10.1152/ajpendo.00407.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The epithelial Na⁺ channels (ENaCs) are present in kidney and contribute to Na⁺ and water homeostasis. All three ENaC subunits (α, β, and γ) were demonstrated in the cardiovascular regulatory centers of the rat brain, including the magnocellular neurons (MNCs) in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN). However, the functional significance of ENaCs in vasopressin (VP) and oxytocin (OT) synthesizing MNCs is completely unknown. In this study, we show with immunocytochemical double-labeling that the α-ENaC is colocalized with either VP or OT in MNCs in the SON and PVN. In addition, parvocellular neurons in the dorsal, ventrolateral, and posterior subregions of the PVN (not immunoreactive to VP or OT) are also immunoreactive for α-ENaC. In contrast, immunoreactivity to β- and γ-ENaC is colocalized with VP alone within the MNCs. Furthermore, immunoreactivity for a known target for ENaC expression, the mineralcorticoid receptor (MR), is colocalized with both VP and OT in MNCs. Using single-cell RT-PCR, we detected mRNA for all three ENaC subunits and MR in cDNA libraries derived from single MNCs. In whole cell voltage clamp recordings, application of the ENaC blocker benzamil reversibly reduced a steady-state inward current and decreased cell membrane conductance approximately twofold. Finally, benzamil caused membrane hyperpolarization in a majority of VP and about one-half of OT neurons in both spontaneously firing and quiet cells. These results strongly suggest the presence of functional ENaCs that may affect the firing patterns of MNCs, which ultimately control the secretion of VP and OT.
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Affiliation(s)
- Ryoichi Teruyama
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
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27
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Sonner PM, Lee S, Ryu PD, Lee SY, Stern JE. Imbalanced K+ and Ca2+ subthreshold interactions contribute to increased hypothalamic presympathetic neuronal excitability in hypertensive rats. J Physiol 2011; 589:667-83. [PMID: 21149460 PMCID: PMC3055550 DOI: 10.1113/jphysiol.2010.198556] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 12/09/2010] [Indexed: 12/12/2022] Open
Abstract
Despite the importance of brain-mediated sympathetic activation in the morbidity and mortality of patients with high blood pressure, the precise cellular mechanisms involved remain largely unknown. We show that an imbalanced interaction between two opposing currents mediated by potassium (I(A)) and calcium (I(T)) channels occurs in sympathetic-related hypothalamic neurons in hypertensive rats. We show that this imbalance contributes to enhanced membrane excitability and firing activity in this neuronal population. Knowledge of how these opposing ion channels interact in normal and disease states increases our understanding of underlying brain mechanisms contributing to the high blood pressure condition.
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Affiliation(s)
- P M Sonner
- Department of Physiology, Medical College of Georgia, Augusta, GA 30912, USA
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28
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Abrams JM, Engeland WC, Osborn JW. Effect of intracerebroventricular benzamil on cardiovascular and central autonomic responses to DOCA-salt treatment. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1500-10. [PMID: 20926762 DOI: 10.1152/ajpregu.00431.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
DOCA-salt treatment increases mean arterial pressure (MAP), while central infusion of benzamil attenuates this effect. The present study used c-Fos immunoreactivity to assess the role of benzamil-sensitive proteins in the brain on neural activity following chronic DOCA-salt treatment. Uninephrectomized rats were instrumented with telemetry transmitters for measurement of MAP and with an intracerebroventricular (ICV) cannula for benzamil administration. Groups included rats receiving DOCA-salt treatment alone, rats receiving DOCA-salt treatment with ICV benzamil, and appropriate controls. At study completion, MAP in vehicle-treated DOCA-salt rats reached 142 ± 4 mmHg. In contrast DOCA-salt rats receiving ICV benzamil had lower MAP (124 ± 3 mmHg). MAP in normotensive controls was 102 ± 3 mmHg. c-Fos immunoreactivity was quantified in the supraoptic nucleus (SON) and across subnuclei of the hypothalamic paraventricular nucleus (PVN), as well as other cardiovascular regulatory sites. Compared with vehicle-treated normotensive controls, c-Fos expression was increased in the SON and all subnuclei of the PVN, but not in other key autonomic nuclei, such as the rostroventrolateral medulla. Moreover, benzamil treatment decreased c-Fos immunoreactivity in the SON and in medial parvocellular and posterior magnocellular neurons of the PVN in DOCA-salt rats but not areas associated with regulation of sympathetic activity. Our results do not support the hypothesis that DOCA-salt increases neuronal activity (as indicated by c-Fos immunoreactivity) of other key regions that regulate sympathetic activity. These results suggest that ICV benzamil attenuates DOCA-salt hypertension by modulation of neuroendocrine-related PVN nuclei rather than inhibition of PVN sympathetic premotor neurons in the PVN and rostroventrolateral medulla.
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Affiliation(s)
- Joanna M Abrams
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
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29
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Díaz-Casares A, López-González MV, Peinado-Aragonés CA, Lara JP, González-Barón S, Dawid-Milner MS. Role of the parabrachial complex in the cardiorespiratory response evoked from hypothalamic defense area stimulation in the anesthetized rat. Brain Res 2009; 1279:58-70. [DOI: 10.1016/j.brainres.2009.02.085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 02/27/2009] [Accepted: 02/27/2009] [Indexed: 11/25/2022]
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30
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Kvetnansky R, Sabban EL, Palkovits M. Catecholaminergic systems in stress: structural and molecular genetic approaches. Physiol Rev 2009; 89:535-606. [PMID: 19342614 DOI: 10.1152/physrev.00042.2006] [Citation(s) in RCA: 347] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Stressful stimuli evoke complex endocrine, autonomic, and behavioral responses that are extremely variable and specific depending on the type and nature of the stressors. We first provide a short overview of physiology, biochemistry, and molecular genetics of sympatho-adrenomedullary, sympatho-neural, and brain catecholaminergic systems. Important processes of catecholamine biosynthesis, storage, release, secretion, uptake, reuptake, degradation, and transporters in acutely or chronically stressed organisms are described. We emphasize the structural variability of catecholamine systems and the molecular genetics of enzymes involved in biosynthesis and degradation of catecholamines and transporters. Characterization of enzyme gene promoters, transcriptional and posttranscriptional mechanisms, transcription factors, gene expression and protein translation, as well as different phases of stress-activated transcription and quantitative determination of mRNA levels in stressed organisms are discussed. Data from catecholamine enzyme gene knockout mice are shown. Interaction of catecholaminergic systems with other neurotransmitter and hormonal systems are discussed. We describe the effects of homotypic and heterotypic stressors, adaptation and maladaptation of the organism, and the specificity of stressors (physical, emotional, metabolic, etc.) on activation of catecholaminergic systems at all levels from plasma catecholamines to gene expression of catecholamine enzymes. We also discuss cross-adaptation and the effect of novel heterotypic stressors on organisms adapted to long-term monotypic stressors. The extra-adrenal nonneuronal adrenergic system is described. Stress-related central neuronal regulatory circuits and central organization of responses to various stressors are presented with selected examples of regulatory molecular mechanisms. Data summarized here indicate that catecholaminergic systems are activated in different ways following exposure to distinct stressful stimuli.
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Affiliation(s)
- Richard Kvetnansky
- Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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31
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Watkins ND, Cork SC, Pyner S. An immunohistochemical investigation of the relationship between neuronal nitric oxide synthase, GABA and presympathetic paraventricular neurons in the hypothalamus. Neuroscience 2009; 159:1079-88. [PMID: 19272339 DOI: 10.1016/j.neuroscience.2009.01.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 12/12/2008] [Accepted: 01/07/2009] [Indexed: 11/27/2022]
Abstract
Functional studies suggest that nitric oxide (NO) modulates sympathetic outflow by enhancing synaptic GABAergic function. Furthermore, the paraventricular nucleus of the hypothalamus (PVN), an important site for autonomic and endocrine homeostasis constitutes an important center mediating NO actions on sympathetic outflow. However, the exact anatomical organization of GABA and NO releasing neurons with the PVN neurons that regulate autonomic activity is poorly understood. The present study addressed this by identifying PVN-presympathetic neurons in the rat with the retrograde tracer Fluorogold injected into T2 segment of the spinal cord or herpes simplex virus injected into the adrenal medulla (AM). GABAergic or nitric oxide cell bodies were identified by antibodies directed towards GABA or glutamate decarboxylase (GAD67) enzyme or neuronal nitric oxide synthase. This revealed a population of GABAergic neurons to be synaptically associated with a chain of pre-sympathetic neurons targeting the AM. Furthermore, this GABAergic population is not a cellular source of NO. Within the PVN, the majority of cellular nitric oxide was localized to non-spinally projecting neurons while for the PVN-spinally projecting neuronal pool only a minority of neuron were immunopositive for neuronal nitric oxide synthase. In summary, nitrergic and GABAergic neurons are associated with a hierarchical chain of neurons that regulate autonomic outflow. This anatomical arrangement supports the known function role of a NO-GABA modulation of sympathetic outflow.
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Affiliation(s)
- N D Watkins
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK
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Abrams JM, Osborn JW. A role for benzamil-sensitive proteins of the central nervous system in the pathogenesis of salt-dependent hypertension. Clin Exp Pharmacol Physiol 2008; 35:687-94. [PMID: 18387084 DOI: 10.1111/j.1440-1681.2008.04929.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
1. Although increasing evidence suggests that salt-sensitive hypertension is a disorder of the central nervous system (CNS), little is known about the critical proteins (e.g. ion channels or exchangers) that play a role in the pathogenesis of the disease. 2. Central pathways involved in the regulation of arterial pressure have been investigated. In addition, systems such as the renin-angiotensin-aldosterone axis, initially characterized in the periphery, are present in the CNS and seem to play a role in the regulation of arterial pressure. 3. Central administration of amiloride, or its analogue benzamil hydrochloride, has been shown to attenuate several forms of salt-sensitive hypertension. In addition, intracerebroventricular (i.c.v.) benzamil effectively blocks pressor responses to acute osmotic stimuli, such as i.c.v. hypertonic saline. Amiloride or its analogues have been shown to interact with the brain renin-angiotensin-aldosterone system (RAAS) and to effect the expression of endogenous ouabain-like compounds. Alterations of brain RAAS function and/or endobain expression could play a role in the interaction between amiloride compounds and arterial pressure. Peripheral treatments with benzamil, even at higher doses than those given centrally, have little or no effect on arterial pressure. These data provide strong evidence that benzamil-sensitive proteins (BSPs) of the CNS play a role in cardiovascular responsiveness to sodium. 4. Mineralocorticoids have been linked to human hypertension; many patients with essential hypertension respond well to pharmacological agents antagonizing the mineralocorticoid receptor and certain genetic forms of hypertension are caused by chronically elevated levels of aldosterone. The deoxycorticosterone acetate (DOCA)-salt model of hypertension is a benzamil-sensitive model that incorporates several factors implicated in the aetiology of human disease, including mineralocorticoid action and increased dietary sodium. The DOCA-salt model is ideal for investigating the role of BSPs in the pathogenesis of hypertension, because mineralocorticoid action has been shown to modulate the activity of at least one benzamil-sensitive protein, namely the epithelial sodium channel. 5. Characterizing the BSPs involved in the pathogenesis of hypertension may provide a novel clinical target. Further studies are necessary to determine which BSPs are involved and where, in the nervous system, they are located.
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Affiliation(s)
- Joanna M Abrams
- Graduate Program in Neuroscience, Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota 55455, USA
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34
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Shahar T, Palkovits M. Cross over of forebrain and brainstem neuronal projections to spinal cord sympathetic preganglionic neurons in the rat. Stress 2007; 10:145-52. [PMID: 17514583 DOI: 10.1080/10253890701424712] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Neuronal inputs from the forebrain and the brainstem to sympathetic preganglionic neurons in the spinal cord were investigated by the transneuronal retrograde tracing technique using pseudorabies virus in intact and brainstem-lesioned rats. After unilateral subcutaneous viral inoculations into the hind limb of intact rats, infected neurons were then visualized by immunostaining. At 3.5 days after inoculation, infected neurons appeared in the thoracic (T10) intermediolateral (IML) cell column. On the 4th day, infected neurons were present in the C1, A5, A6, A7 catecholamine cell groups and the rostral ventromedial medulla (RVMM). On the 5th day, viral labeling was seen in the hypothalamic paraventricular and arcuate nuclei and the lateral hypothalamic area. In all of these nuclei, the infected cells appeared bilaterally. However, the appearance of virus-labeled cells in these nuclei was unilateral following unilateral coronal sections between the medulla and the spinal cord (depending on the side of hemisection, but not on the site of virus inoculation). Midsagittal sections throughout the entire medulla oblongata did not alter the topographical pattern of virus-infected neurons in the forebrain or the brainstem. These findings indicate that descending fibers to the spinal neurons may not cross over in the lower brainstem but that they decussate within the spinal cord.
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Affiliation(s)
- Tal Shahar
- Laboratory of Neuromorphology and Neuroendocrinology, Semmelweis University and Hungarian Academy of Sciences, Budapest, Hungary
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35
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Womack MD, Morris R, Gent TC, Barrett-Jolley R. Substance P targets sympathetic control neurons in the paraventricular nucleus. Circ Res 2007; 100:1650-8. [PMID: 17495222 DOI: 10.1161/circresaha.107.153494] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The paraventricular nucleus (PVN) contains spinally-projecting neurons implicated in fine-tuning the cardiovascular system. In vivo activity of "presympathetic" parvocellular neurons is suppressed by tonic inhibition from GABA-ergic inputs, inhibition of which increases sympathetic pressor activity and heart rate. Targeting of this specific neuronal population could potentially limit elevations of heart rate and blood pressure associated with disease. Here we show, for the first time, that "presympathetic" PVN neurons are disinhibited by the neuropeptide substance P (SP) acting via tachykinin NK1 receptor inhibition of GABA(A) currents. Application of SP to the paraventricular nucleus of rats increases heart rate and blood pressure. In in vitro brain slice experiments, in the presence of GABA, 1 micromol/L SP increased action current frequency by a factor of 2.7+/-0.6 (n=5, P< or =0.05, ANOVA). Furthermore, 1 micromol/L SP inhibited GABA(A) currents by 70+/-8% (n=8, P< or =0.005 paired t test). These effects were abolished by NK1 antagonists, but not NK2 and NK3 antagonists. GABA(A) inhibition was not reproduced by NK2 or NK3 agonists. The inhibition of parvocellular GABA(A) currents by SP was also abolished by a protein kinase C (PKC) inhibitor peptide and mimicked by application of phorbol-12-myristate-13-acetate (PMA), implicating a PKC-dependent mechanism. Single-channel analysis indicates that SP acts through reduction of channel mean open-time (cmot): GABA(A) cmot being reduced by approximately 60% by SP (P< or =0.05 ANOVA, Bonferroni). These data suggest that tachykinins mediate their pressor activity by increasing the excitability of spinally-projecting neurons and identifies NK1 receptors as potential targets for therapeutic modulation of the cardiovascular system.
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Affiliation(s)
- Matthew D Womack
- Veterinary Sciences Faculty, Brownlow Hill, University of Liverpool, UK
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36
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Balcita-Pedicino JJ, Rinaman L. Noradrenergic axon terminals contact gastric preautonomic neurons in the paraventricular nucleus of the hypothalamus in rats. J Comp Neurol 2007; 501:608-18. [PMID: 17278138 DOI: 10.1002/cne.21267] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hypothalamic neural activity is modulated by viscerosensory signals that are carried in large part by noradrenergic (NA) inputs to the paraventricular nucleus of the hypothalamus (PVN). The present study examined the ultrastructural relationship of NA axon varicosities with the somata and dendrites of identified gastric preautonomic PVN neurons in adult male rats. NA varicosities were visualized by immunoperoxidase labeling of dopamine beta hydroxylase (DbH), and gastric preautonomic PVN neurons were identified by immunogold labeling of pseudorabies virus (PRV) transported retrogradely and transneuronally from injection sites in the stomach wall. Among 1,136 DbH-positive varicosities identified within the parvocellular PVN in four rats, approximately 36% formed either a close apposition or a synaptic contact with a somatic or dendritic profile. The majority of identified contacts between DbH- and PRV-positive profiles were classified as close appositions that lacked clear synaptic specializations. Approximately 65% of identified synaptic contacts between DbH- and PRV-positive profiles were classified as symmetric (Gray's type II) synapses. DbH-positive terminals formed close appositions and synaptic contacts with dendritic and somatic compartments of PRV-positive neurons, although dendrites were contacted nearly five times more often than somata. These findings invite continued work to delineate the functional role of NA signaling pathways in conveying interoceptive signals to preautonomic PVN neurons under normal and pathophysiological conditions.
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Affiliation(s)
- J J Balcita-Pedicino
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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37
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DAS MAHASWETA, VIHLEN CHRISTOPHERS, LEGRADI GABOR. Hypothalamic and brainstem sources of pituitary adenylate cyclase-activating polypeptide nerve fibers innervating the hypothalamic paraventricular nucleus in the rat. J Comp Neurol 2007; 500:761-76. [PMID: 17154257 PMCID: PMC1934940 DOI: 10.1002/cne.21212] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The hypothalamic paraventricular nucleus (PVN) coordinates major neuroendocrine and behavioral mechanisms, particularly responses to homeostatic challenges. Parvocellular and magnocellular PVN neurons are richly innervated by pituitary adenylate cyclase-activating polypeptide (PACAP) axons. Our recent functional observations have also suggested that PACAP may be an excitatory neuropeptide at the level of the PVN. Nevertheless, the exact localization of PACAP-producing neurons that project to the PVN is not understood. The present study examined the specific contribution of various brain areas sending PACAP innervation to the rat PVN by using iontophoretic microinjections of the retrograde neuroanatomical tracer cholera toxin B subunit (CTb). Retrograde transport was evaluated from hypothalamic and brainstem sections by using multiple labeling immunofluorescence for CTb and PACAP. PACAP-containing cell groups were found to be retrogradely labeled from the PVN in the median preoptic nucleus; preoptic and lateral hypothalamic areas; arcuate, dorsomedial, ventromedial, and supramammillary nuclei; ventrolateral midbrain periaqueductal gray; rostral and midlevel ventrolateral medulla, including the C1 catecholamine cell group; nucleus of the solitary tract; and dorsal motor nucleus of vagus. Minor PACAP projections with scattered double-labeled neurons originated from the parabrachial nucleus, pericoeruleus area, and caudal regions of the nucleus of the solitary tract and ventrolateral medulla. These observations indicate a multisite origin of PACAP innervation to the PVN and provide a strong chemical neuroanatomical foundation for interaction between PACAP and its potential target neurons in the PVN, such as parvocellular CRH neurons, controlling physiologic responses to stressful challenges and other neuroendocrine or preautonomic PVN neurons.
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Affiliation(s)
| | | | - GABOR LEGRADI
- *Correspondence to: Gabor Legradi, MD, Department of Pathology and Cell Biology, College of Medicine University of South Florida, 12901 Bruce B. Downs Blvd., MDC6, Tampa, FL 33612-4799. E-mail:
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Boyadjieva N, Advis JP, Sarkar DK. Role of beta-endorphin, corticotropin-releasing hormone, and autonomic nervous system in mediation of the effect of chronic ethanol on natural killer cell cytolytic activity. Alcohol Clin Exp Res 2006; 30:1761-7. [PMID: 17010143 DOI: 10.1111/j.1530-0277.2006.00209.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND We have recently shown that alcohol feeding suppresses natural killer (NK) cell cytolytic activity partly by decreasing the function of hypothalamic beta-endorphin (beta-EP) neurons. The neuronal mechanism by which hypothalamic beta-EP communicates with the spleen to regulate the action of ethanol on NK cells is not known. In the present study, we evaluated the roles of beta-EP neurons, corticotropin releasing hormone (CRH) neurons, and the autonomic nervous system (ANS) in regulation of the ethanol effect on splenic NK cell cytolytic function. METHODS Male rats were fed an ethanol-containing liquid diet or control diets. These rats were used to determine the hormone release from the paraventricular nuclei (PVN) of the hypothalamus or used to determine the splenic NK cell cytolytic function after PVN administration of CRH or intraperitoneal (i.p.) administration of a ganglionic blocker chlorisondamine. The release of hormones from the PVN was measured using the push-pull perfusion method. Splenic cytolytic activity was determined using the 4-hour (51)Cr release assay against YAC-1 lymphoma target cells. RESULTS Alcohol feeding decreased the amount of beta-EP but increased the amount of CRH in the push-pull perfusate (PPP) samples collected from the PVN. When exogenous beta-EP was perfused into the PVN, it suppressed the release of endogenous CRH found in PPP samples of the PVN. Conversely, perfusion of an opiate antagonist naltrexone into the PVN increased the levels of endogenous CRH in PPP samples of the PVN. In addition, administration of exogenous beta-EP in the PVN stimulated the cytolytic function of NK cells, an action that was antagonized by CRH as well as by ethanol. Corticotropin-releasing hormone and ethanol alone also had an inhibitory action on NK cells. Finally, the ganglionic blocker used prevented the effect that ethanol, beta-EP, and CRH had on NK cells. These data suggest that ethanol inhibits the function of NK cells partly by suppressing the influence of the beta-EP-CRH-ANS signal to the spleen.
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Affiliation(s)
- Nadka Boyadjieva
- Endocrine Program, Center of Alcohol Studies and Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA
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39
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Womack MD, Pyner S, Barrett-Jolley R. Inhibition by alpha-tetrahydrodeoxycorticosterone (THDOC) of pre-sympathetic parvocellular neurones in the paraventricular nucleus of rat hypothalamus. Br J Pharmacol 2006; 149:600-7. [PMID: 17001301 PMCID: PMC2014678 DOI: 10.1038/sj.bjp.0706911] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE alpha-tetrahydrodeoxycorticosterone (THDOC) is an endogenous neuroactive steroid which increases in plasma and brain concentration during stress. It has both positive and negative modulatory effects on GABA activated GABAA currents, dependent upon the dose. We investigated the effects of THDOC on spinally-projecting "pre-sympathetic" neurones in the parvocellular subnucleus of the hypothalamic paraventricular nucleus (PVN), to determine whether it activates or inhibits these neurones, and by what mechanism. EXPERIMENTAL APPROACH Rat spinally-projecting (parvocellular) PVN neurones were identified by retrograde labelling and the action of THDOC investigated with three modes of patch-clamp: cell-attached action current, whole-cell voltage-clamp and cell-attached single-channel recording. KEY RESULTS In cell-attached patch mode, parvocellular neurones fired action potentials spontaneously with an average frequency of 3.6 +/- 1.1 Hz. Bath application of THDOC reduced this with an EC50 of 67 nM (95% confidence limits: 54 to 84 nM), Hill coefficient 0.8 +/- 0.04, n = 5. In whole-cell patch-clamp mode, pressure ejection of GABA evoked inward currents. These were clearly GABAA currents, since they were inhibited by the GABAA receptor antagonist bicuculline, and reversed near the chloride equilibrium potential. THDOC significantly potentiated GABAA currents (1 microM THDOC: 148 +/- 15% of control, n = 5, p < or = 0.05, ANOVA). Single-channel analysis showed no differences in conductance or corrected mean open times in the presence of 1 microM THDOC. CONCLUSIONS AND IMPLICATIONS THDOC inhibited parvocellular neuronal activity without showing any evidence of the bidirectional activity demonstrated previously with cultured hypothalamic neurones. Our data are consistent with the hypothesis that THDOC acts by potentiating the post-synaptic activity of endogenously released GABA.
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Affiliation(s)
- M D Womack
- Department of Veterinary Preclinical Sciences, University of Liverpool Liverpool, UK
| | - S Pyner
- School of Biological & Biomedical Sciences, Science Laboratories, University of Durham Durham, UK
| | - R Barrett-Jolley
- Department of Veterinary Preclinical Sciences, University of Liverpool Liverpool, UK
- Author for correspondence:
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Reddy MK, Schultz HD, Zheng H, Patel KP. Altered nitric oxide mechanism within the paraventricular nucleus contributes to the augmented carotid body chemoreflex in heart failure. Am J Physiol Heart Circ Physiol 2006; 292:H149-57. [PMID: 16891408 DOI: 10.1152/ajpheart.00117.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our previous study demonstrated a contribution of the paraventricular nucleus (PVN) of the hypothalamus in the processing of the carotid body (CB) chemoreflex. Nitric oxide (NO) (within the PVN), known to modulate autonomic function, is altered in rats with heart failure (HF). Therefore, the goal of the present study was to examine the influence of endogenous and exogenous NO within the PVN on the sympathoexcitatory component of the peripheral chemoreflex in normal and HF states. We measured mean arterial blood pressure, heart rate, renal sympathetic nerve activity (RSNA), and phrenic nerve activity (PNA) in sham-operated and HF rats (6-8 wk after coronary artery ligation) after incremental doses of potassium cyanide (25-100 mug/kg iv). There was potentiation of the reflex responses in HF compared with sham-operated rats. Bilateral microinjection of an inhibitor of NO synthase, N(G)-monomethyl-l-arginine (50 pmol), into the PVN augmented the RSNA and PNA response to peripheral chemoreceptor stimulation in sham-operated rats but had no effect in HF rats. Conversely, bilateral microinjection of a NO donor, sodium nitroprusside (50 nmol), into the PVN attenuated the RSNA response of the peripheral chemoreflex in sham-operated rats but to a smaller extent in HF rats. These data indicate that 1) NO within the PVN plays an important role in the processing of the CB chemoreflex and 2) there is an impairment of the NO function within the PVN of HF rats, which contributes to an augmented peripheral chemoreflex and subsequent elevation of sympathetic activity in HF.
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Affiliation(s)
- Maram K Reddy
- Dept. of Cellular & Integrative Physiology, Univ. of Nebraska College of Medicine, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Han SM, Namkoong C, Jang PG, Park IS, Hong SW, Katakami H, Chun S, Kim SW, Park JY, Lee KU, Kim MS. Hypothalamic AMP-activated protein kinase mediates counter-regulatory responses to hypoglycaemia in rats. Diabetologia 2005; 48:2170-8. [PMID: 16132951 DOI: 10.1007/s00125-005-1913-1] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Accepted: 05/26/2005] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESIS Appropriate counter-regulatory hormonal responses are essential for recovery from hypoglycaemia. Although the hypothalamus is known to be involved in these responses, the molecular mechanisms have not been fully elucidated. AMP-activated protein kinase (AMPK) functions as a cellular energy sensor, being activated during energy depletion. As AMPK is expressed in the hypothalamus, an important site of neuroendocrine regulation, the present study was undertaken to determine whether hypothalamic AMPK mediates counter-regulatory responses to hypoglycaemia. MATERIALS AND METHODS Hypoglycaemia was induced by i.p. injection of regular insulin (6 U/kg) in Sprague-Dawley rats. Hypothalamic AMPK phosphorylation and activities were determined 1 h after i.p. insulin injection. To investigate the role of hypothalamic AMPK activation in mediating counter-regulatory responses, an AMPK inhibitor, compound C, was pre-administered intracerebroventricularly (i.c.v.) or dominant-negative (DN)-AMPK was overexpressed in the hypothalamus before induction of hypoglycaemia. RESULTS Insulin-induced hypoglycaemia increased hypothalamic AMPK phosphorylation and alpha2-AMPK activities in rats. The change was significant in the arcuate nucleus/ventromedial hypothalamus (ARC/VMH) and paraventricular nuclei (PVN). Prior i.c.v. administration of compound C attenuated hypoglycaemia-induced increases in plasma concentrations of corticosterone, glucagon and catecholamines, resulting in severe and prolonged hypoglycaemia. ARC/VMH DN-AMPK overexpression impaired early counter-regulation, as evidenced by reduced glucagon and catecholamine responses. In contrast, PVN DN-AMPK overexpression attenuated late counter-regulation and corticosterone responses. CONCLUSIONS/INTERPRETATION Systemic hypoglycaemia causes hypothalamic AMPK activation, which is important for counter-regulatory hormonal responses. Our data indicate that hypothalamic AMPK acts as a fuel gauge, sensing the whole-body energy state and regulating not only energy homeostasis but also neuroendocrine functions.
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Affiliation(s)
- S-M Han
- Department of Internal Medicine, University of Ulsan College of Medicine, Poongnap-dong, Songpa-gu, Seoul 138-736, South Korea
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Abstract
Certain neurotropic viruses can invade the nervous system of their hosts and spread in chains of synaptically connected neurons. Consequently, it is possible to identify entire hierarchically connected circuits within an animal. In this review, we discuss the use of neurotropic herpesviruses as neuronal tract tracers. Although a variety of tract tracing viruses are available, each with its own unique infection characteristics, we focus on the widespread use of attenuated strains of pseudorabies virus (PRV), a swine herpesvirus with a broad host range. In particular, we focus on new applications of PRV for tract tracing including use of multiple infections by PRV reporter viruses to test for circuit convergence/divergence within the same animal. We provide examples of these combined application techniques within the context of an animal model to study the naturally occurring reversal of seasonal obesity in Siberian hamsters.
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Affiliation(s)
- C Kay Song
- Department of Biology, Neurobiology and Behavior Program, Georgia State University, 24 Peachtree Center Ave. NE, Atlanta, GA 30302-4010, USA
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Reddy MK, Patel KP, Schultz HD. Differential role of the paraventricular nucleus of the hypothalamus in modulating the sympathoexcitatory component of peripheral and central chemoreflexes. Am J Physiol Regul Integr Comp Physiol 2005; 289:R789-97. [PMID: 15919733 DOI: 10.1152/ajpregu.00222.2005] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study we investigated the involvement of the hypothalamic paraventricular nucleus (PVN) in the modulation of sympathoexcitatory reflex activated by peripheral and central chemoreceptors. We measured mean arterial blood pressure (MAP), heart rate (HR), renal sympathetic nerve activity (RSNA), and phrenic nerve activity (PNA) before and after blocking neurotransmission within the PVN by bilateral microinjection of 2% lidocaine (100 nl) during specific stimulation of peripheral chemoreceptors by potassium cyanide (KCN, 75 microg/kg iv, bolus dose) or stimulation of central chemoreceptors with hypercapnia (10% CO(2)). Typically stimulation of peripheral chemoreceptors evoked a reflex response characterized by an increase in MAP, RSNA, and PNA and a decrease in HR. Bilateral microinjection of 2% lidocaine into the PVN had no effect on basal sympathetic and cardiorespiratory variables; however, the RSNA and PNA responses evoked by peripheral chemoreceptor stimulation were attenuated (P < 0.05). Bilateral microinjection of bicuculline (50 pmol/50 nl, n = 5) into the PVN augmented the RSNA and PNA response to peripheral chemoreceptor stimulation (P < 0.05). Conversely, the GABA agonist muscimol (0.2 nmol/50 nl, n = 5) injected into the PVN attenuated these reflex responses (P < 0.05). Blocking neurotransmission within the PVN had no effect on the hypercapnia-induced central chemoreflex responses in carotid body denervated animals. These results suggest a selective role of the PVN in processing the sympathoexcitatory and ventilatory component of the peripheral, but not central, chemoreflex.
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Affiliation(s)
- Maram K Reddy
- Dept. of Cellular & Integrative Physiology, University of Nebraska College of Medicine, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Mousa TM, Gao L, Cornish KG, Zucker IH. Effects of angiotensin II on autonomic components of nasopharyngeal stimulation in male conscious rabbits. J Appl Physiol (1985) 2005; 98:1607-11. [PMID: 15649867 DOI: 10.1152/japplphysiol.01322.2004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Angiotensin II (ANG II) is known to activate central sympathetic neurons. In this study we determined the effects of ANG II on the autonomic components of the cardiovascular responses to stimulation of nasopharyngeal receptors with cigarette smoke. Experiments were carried out in conscious New Zealand White rabbits instrumented to record arterial pressure and heart rate. Rabbits were exposed to 50 ml of cigarette smoke before and after subcutaneous osmotic minipump delivery of ANG II at a dose of 50 ng.kg(-1).min(-1) for 1 wk in one group and intracerebroventricular (icv) infusion at a dose of 100 pmol/min for 1 h in a second group. The responses were compared before and after heart rate was controlled by pacing. Autonomic components were evaluated by intravenous administration of atropine methyl bromide (0.2 mg/kg) and prazosin (0.5 mg/kg). ANG II given either systemically or icv significantly blunted the pressor response to smoke (P < 0.05) when the bradycardic response was prevented. This blunted response was not due to an absolute increase in baseline blood pressure after ANG II infusion (71.64 +/- 11.6 vs. 92.1 +/- 19.8 mmHg; P < 0.05) because normalization of blood pressure with sodium nitroprusside to pre-ANG II levels also resulted in a significantly blunted pressor response to smoke. The effect of smoke was alpha(1)-adrenergic receptor-mediated because it was essentially abolished by prazosin in both the pre- and the post-ANG II states (P < 0.05). These results suggest that elevations in central ANG II reduce the sympathetic response to smoke in conscious rabbits. This effect may be due to an augmentation of baseline sympathetic outflow and a reduction in reflex sensitivity similar to the effect of ANG II on baroreflex function.
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Affiliation(s)
- Tarek M Mousa
- Department of Cellular and Integrative Physiology, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA
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45
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Fernandes LG, Antunes VR, Bonagamba LGH, Machado BH. Pressor response to chemoreflex activation in awake rats: role of vasopressin and adrenal medulla. Physiol Behav 2005; 84:39-44. [PMID: 15642605 DOI: 10.1016/j.physbeh.2004.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 09/03/2004] [Accepted: 10/14/2004] [Indexed: 10/26/2022]
Abstract
The possible role of the peptide vasopressin and adrenal catecholamine in the pressor response to chemoreflex activation was evaluated in awake rats. Data show that the peripheral blockade of the V1 vasopressin receptor produced no change in the cardiovascular responses to chemoreflex activation, indicating that vasopressin plays no role on the pressor response to chemoreflex activation. We also have shown that the pressor response to chemoreflex activation is dependent on the sympathetic efferent activity since the antagonism of the alpha1-adrenoceptor with prazosin almost abolished the pressor response to chemoreflex activation. Furthermore, bilateral adrenal demedullation produced no change on the pressor response to chemoreflex activation, outpointing that the release of catecholamines by the adrenal medulla is not involved in the pressor response to chemoreflex. We conclude that the pressor response to chemoreflex activation is essentially mediated by the sympathetic innervations to the peripheral vascular beds.
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Affiliation(s)
- Luciano G Fernandes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil
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Wang Y, Liu XF, Cornish KG, Zucker IH, Patel KP. Effects of nNOS antisense in the paraventricular nucleus on blood pressure and heart rate in rats with heart failure. Am J Physiol Heart Circ Physiol 2004; 288:H205-13. [PMID: 15331368 DOI: 10.1152/ajpheart.00497.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using neuronal NO synthase (nNOS)-specific antisense oligonucleotides, we examined the role of nitric oxide (NO) in the paraventricular nucleus (PVN) on control of blood pressure and heart rate (HR) in conscious sham rats and rats with chronic heart failure (CHF). After 6-8 wk, rats with chronic coronary ligation showed hemodynamic and echocardiographic signs of CHF. In sham rats, we found that microinjection of sodium nitroprusside (SNP, 20 nmol, 100 nl) into the PVN induced a significant decrease in mean arterial pressure (MAP). SNP also induced a significant decrease in HR over the next 10 min. In contrast, the NOS inhibitor N(G)-monomethyl-L-arginine (L-NMMA, 200 pmol, 100 nl) significantly increased MAP and HR over the next 18-20 min. After injection of nNOS antisense, MAP was significantly increased in sham rats over the next 7 h. The peak response was 27.6 +/- 4.1% above baseline pressure. However, in the CHF rats, only MAP was significantly increased. The peak magnitude was 12.9 +/- 5.4% of baseline, which was significantly attenuated compared with sham rats (P < 0.01). In sham rats, the pressor response was completely abolished by alpha-receptor blockade. HR was significantly increased from hour 1 to hour 7 in sham and CHF rats. There was no difference in magnitude of HR responses. The tachycardia could not be abolished by the beta(1)-blocker metoprolol. However, the muscarinic receptor antagonist atropine did not further augment the tachycardia. We conclude that NO induces a significant depressor and bradycardiac response in normal rats. The pressor response is mediated by an elevated sympathetic tone, whereas the tachycardia is mediated by withdrawal of parasympathetic tone in sham rats. These data are consistent with a downregulation of nNOS within the PVN in CHF.
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Affiliation(s)
- Yu Wang
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-4575, USA
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Yang Z, Smith L, Coote JH. Paraventricular nucleus activation of renal sympathetic neurones is synaptically depressed by nitric oxide and glycine acting at a spinal level. Neuroscience 2004; 124:421-8. [PMID: 14980391 DOI: 10.1016/j.neuroscience.2003.10.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2003] [Indexed: 11/18/2022]
Abstract
A high density of nitric oxide synthesising enzyme is present in sympathetic preganglionic neurones in the spinal cord. It has been shown that nitric oxide is released as a consequence of synaptic activity. In the present study in anaesthetised rats we determined if nitric oxide acted as a retrograde messenger molecule to modulate the excitatory effects on the renal sympathetic spinal network elicited by paraventricular nucleus stimulation. Neurones in the latter nucleus were stimulated by microinjecting DLH and drugs were applied to the spinal cord via an intrathecal catheter with the tip positioned at T9-T10. Intrathecal application of the nitric oxide donors, sodium nitroprusside or [3-(2-hydroxy-1-methyl-2-nitrosohydrazino)-N-methyl-1-propanamine] significantly increased tonic activity in the renal sympathetic nerve. In contrast synaptic activity evoked by intrathecal glutamate or by paraventricular nucleus stimulation was enhanced by preventing nitric oxide generation with intrathecal N(G)-monomethyl-L-arginine monoacetate (L-NMMA) a nitric oxide synthase inhibitor. Enhancement of synaptically induced renal nerve activity was also observed following intrathecal glycine receptor inhibitor strychnine. Strychnine was without effect when it was given after L-NMMA. It was concluded that paraventricular nucleus excitation of renal sympathetic neurones is subject to inhibitory modulation by released nitric oxide and it is suggested the latter acts via glycine interneurones.
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Affiliation(s)
- Z Yang
- Department of Physiology, Division of Medical Sciences, School of Medicine, The University of Birmingham, Birmingham B15 2TT, UK
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48
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Greenwood BN, Kennedy S, Smith TP, Campeau S, Day HEW, Fleshner M. Voluntary freewheel running selectively modulates catecholamine content in peripheral tissue and c-Fos expression in the central sympathetic circuit following exposure to uncontrollable stress in rats. Neuroscience 2003; 120:269-81. [PMID: 12849759 DOI: 10.1016/s0306-4522(03)00047-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Modulation of sympathetic drive to the spleen is one potential mechanism whereby physical activity prevents stress-induced splenic immune suppression in rats. The current study tested the hypothesis that voluntary freewheel running reduces peripheral sympathetic drive by modulating stress-induced activity of brain regions synaptically linked to sympathetically innervated peripheral organs, including the adrenals and spleen. To this end, adrenal and splenic catecholamine content and activity of the central sympathetic circuit indexed by c-Fos protein induction, elicited by acute exposure to inescapable tail shock, were measured. Stressor exposure depleted adrenal and splenic norepinephrine content and elicited a robust increase in c-Fos in the brains of sedentary rats. Physical activity status had no effect on adrenal norepinephrine content. Indicative of attenuated sympathetic drive to the spleen, however, 6 weeks of voluntary freewheel running diminished stress-induced splenic norepinephrine depletion, and significantly attenuated stress-induced c-Fos in specific brain regions responsible for sympathetic regulation, including tyrosine hydroxylase-immunoreactive neurons of the locus coeruleus, A5 cell group and rostral ventrolateral medulla. Results suggest that voluntary activity attenuates sympathetic drive to the spleen during stressor exposure by selectively modulating stress-induced activity of the central sympathetic circuit. The attenuation of sympathetic responses observed in this study may be one important mechanism for the protective effect of physical activity against stress-related illness and immunosuppression.
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Affiliation(s)
- B N Greenwood
- Department of Kinesiology and Applied Physiology, University of Colorado, Boulder, CO 80309, USA
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Stern JE, Zhang W. Preautonomic neurons in the paraventricular nucleus of the hypothalamus contain estrogen receptor beta. Brain Res 2003; 975:99-109. [PMID: 12763597 DOI: 10.1016/s0006-8993(03)02594-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Central actions of estrogen (E2) include, among others, modulation of autonomic and cardiovascular function. Despite the well-known influence of sex steroid hormones on the incidence of cardiovascular disorders, little is known about the neural substrates and receptors mediating central E2 actions on autonomic function. The paraventricular nucleus of the hypothalamus (PVN) is an important site for the integration of neuroendocrine and autonomic function. Interestingly, while this region was originally found to lack the classical ERalpha receptor, recent studies demonstrated a high degree of expression of the ERbeta subtype. To determine specifically whether autonomic-related neurons in the PVN express ERbeta, thus constituting a neuronal substrate for central E2 actions on autonomic function, we carried out an immunohistochemical study of ERbeta expression in a subpopulation of PVN neurons that innervate the rostroventrolateral medulla (RVLM). ERbeta immunostained neurons were found in medial and caudal aspects of the PVN, overlapping with the distribution of RVLM-projecting neurons. Overall, approximately 50% of RVLM-projecting PVN neurons expressed ERbeta immunoreactivity. Interestingly, the degree of colocalization was found to be sex-dependent (higher expression in males), and varied according to the topographical distribution of neurons within the PVN. ERbeta immunoreactivity was also observed in magnocellular compartments of the PVN, although this appeared to be consistently weaker than that observed in autonomic-related subnuclei. These studies demonstrate for the first time ERbeta expression in identified autonomic-related neurons in the PVN, and suggest that these neurons constitute an important neuronal substrate mediating E2 actions on autonomic and cardiovascular control.
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Affiliation(s)
- J E Stern
- Department of Pharmacology and Toxicology, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45345, USA.
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Evans SB, Wilkinson CW, Gronbeck P, Bennett JL, Taborsky GJ, Figlewicz DP. Inactivation of the PVN during hypoglycemia partially simulates hypoglycemia-associated autonomic failure. Am J Physiol Regul Integr Comp Physiol 2003; 284:R57-65. [PMID: 12388440 DOI: 10.1152/ajpregu.00439.2002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The anatomic connections of the paraventricular nucleus of the hypothalamus (PVN) are such that it is ideally situated to modulate and/or control autonomic responses to a variety of stressors, including hypoglycemia. In our experimental model of hypoglycemia-associated autonomic failure (HAAF), a syndrome in which the counterregulatory response to hypoglycemia is partially compromised via unknown mechanisms, activation of the PVN is blunted (15). We hypothesized that this blunted PVN activation during HAAF may be sufficient to cause the impaired counterregulatory response. To test this hypothesis, we anesthetized the PVN with lidocaine during insulin-induced hypoglycemia in rats and measured counterregulatory hormone levels. PVN inactivation decreased indexes of the sympathoadrenal response (plasma epinephrine and norepinephrine) and the hypothalamic-pituitary axis response (ACTH). Inactivation decreased the peak epinephrine response to hypoglycemia by almost half (-42 +/- 6% from control; P = 0.04) and the peak norepinephrine response by 34 +/- 5% (P = 0.01). The peak plasma ACTH levels attained were suppressed by 35 +/- 6% (P = 0.02). Adrenal corticosterone and pancreatic glucagon responses were not impaired. This pattern of neuroendocrine response is unlike that previously seen with our HAAF model. Control infusions of lidocaine >or=1 mm anterior or posterior to the PVN did not simulate this neuroendocrine pattern. Thus it appears that decreased PVN activation, as occurs with HAAF, may be involved in specific components of HAAF (i.e., blunting the sympathoadrenal and hypothalamic-pituitary-adrenocortical axis response), but not in others (i.e., blunting the glucagon response).
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Affiliation(s)
- Scott B Evans
- Departments of Psychology and of Medicine, University of Washington, Seattle 98195, USA.
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