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Patel M, Braun J, Lambert G, Kameneva T, Keatch C, Lambert E. Central mechanisms in sympathetic nervous dysregulation in obesity. J Neurophysiol 2023; 130:1414-1424. [PMID: 37910522 DOI: 10.1152/jn.00254.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/16/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023] Open
Abstract
Cardiovascular and metabolic complications associated with excess adiposity are linked to chronic activation of the sympathetic nervous system, resulting in a high risk of mortality among obese individuals. Obesity-related positive energy balance underlies the progression of hypertension, end-organ damage, and insulin resistance, driven by increased sympathetic tone throughout the body. It is, therefore, important to understand the central network that drives and maintains sustained activation of the sympathetic nervous system in the obese state. Experimental and clinical studies have identified structural changes and altered dynamics in both grey and white matter regions in obesity. Aberrant activation in certain brain regions has been associated with altered reward circuitry and metabolic pathways including leptin and insulin signaling along with adiposity-driven systemic and central inflammation. The impact of these pathways on the brain via overactivity of the sympathetic nervous system has gained interest in the past decade. Primarily, the brainstem, hypothalamus, amygdala, hippocampus, and cortical structures including the insular, orbitofrontal, temporal, cingulate, and prefrontal cortices have been identified in this context. Although the central network involving these structures is much more intricate, this review highlights recent evidence identifying these regions in sympathetic overactivity in obesity.
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Affiliation(s)
- Mariya Patel
- School of Health Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Joe Braun
- School of Health Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Gavin Lambert
- School of Health Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Tatiana Kameneva
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Melbourne, Victoria, Australia
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria, Australia
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, Victoria, Australia
| | - Charlotte Keatch
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria, Australia
| | - Elisabeth Lambert
- School of Health Sciences, Swinburne University of Technology, Melbourne, Victoria, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Melbourne, Victoria, Australia
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2
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Leo DG, Ozdemir H, Lane DA, Lip GYH, Keller SS, Proietti R. At the heart of the matter: how mental stress and negative emotions affect atrial fibrillation. Front Cardiovasc Med 2023; 10:1171647. [PMID: 37408656 PMCID: PMC10319071 DOI: 10.3389/fcvm.2023.1171647] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/07/2023] [Indexed: 07/07/2023] Open
Abstract
Atrial fibrillation (AF) is the most common form of cardiac arrhythmia, affecting 2%-3% of the world's population. Mental and emotional stress, as well as some mental health conditions (e.g., depression) have been shown to significantly impact the heart and have been suggested to act both as independent risk factors and triggers in the onset of AF. In this paper, we review the current literature to examine the role that mental and emotional stress have in the onset of AF and summarise the current knowledge on the interaction between the brain and heart, and the cortical and subcortical pathways involved in the response to stress. Review of the evidence suggests that mental and emotional stress negatively affect the cardiac system, potentially increasing the risk for developing and/or triggering AF. Further studies are required to further understand the cortical and sub-cortical structures involved in the mental stress response and how these interact with the cardiac system, which may help in defining new strategies and interventions to prevent the development of, and improve the management of AF.
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Affiliation(s)
- Donato Giuseppe Leo
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, United Kingdom
- Department of Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Hizir Ozdemir
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, United Kingdom
| | - Deirdre A. Lane
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, United Kingdom
- Department of Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
- Danish Center for Clinical Health Services Research, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Gregory Y. H. Lip
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, United Kingdom
- Department of Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
- Danish Center for Clinical Health Services Research, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Simon S. Keller
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Riccardo Proietti
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, United Kingdom
- Department of Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
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3
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Reynolds CA, Minic Z. Chronic Pain-Associated Cardiovascular Disease: The Role of Sympathetic Nerve Activity. Int J Mol Sci 2023; 24:5378. [PMID: 36982464 PMCID: PMC10049654 DOI: 10.3390/ijms24065378] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/26/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
Chronic pain affects many people world-wide, and this number is continuously increasing. There is a clear link between chronic pain and the development of cardiovascular disease through activation of the sympathetic nervous system. The purpose of this review is to provide evidence from the literature that highlights the direct relationship between sympathetic nervous system dysfunction and chronic pain. We hypothesize that maladaptive changes within a common neural network regulating the sympathetic nervous system and pain perception contribute to sympathetic overactivation and cardiovascular disease in the setting of chronic pain. We review clinical evidence and highlight the basic neurocircuitry linking the sympathetic and nociceptive networks and the overlap between the neural networks controlling the two.
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Affiliation(s)
- Christian A. Reynolds
- Department of Emergency Medicine, Wayne State University School of Medicine, 540 E Canfield St., Detroit, MI 48201, USA
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
| | - Zeljka Minic
- Department of Emergency Medicine, Wayne State University School of Medicine, 540 E Canfield St., Detroit, MI 48201, USA
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
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Sanetra AM, Palus-Chramiec K, Chrobok L, Lewandowski MH. Electrophysiological complexity in the rat dorsomedial hypothalamus and its susceptibility to daily rhythms and high-fat diet. Eur J Neurosci 2022; 56:4363-4377. [PMID: 35796742 DOI: 10.1111/ejn.15759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 06/10/2022] [Accepted: 06/10/2022] [Indexed: 12/30/2022]
Abstract
The dorsomedial hypothalamus (DMH) in amongst the most important brain structures involved in the regulation of feeding behaviour and metabolism. In contrast to other hypothalamic centres, its main role is related to the circadian rhythmicity of food intake and energy homeostasis; both reported to be disrupted in obesity. In modern world, overweight and obesity reached global epidemic proportions. Thus, not only is it important to study their negative implications but also the mechanism responsible for their development. Here, we exposed rats to short-term (2-4 weeks) high-fat diet (HFD)-not long enough to induce obesity. Next, we performed electrophysiological patch-clamp recordings ex vivo from neurons in the DMH either during the day or at night. Our results showed a day-to-night change in the firing frequency of DMH cells, with higher activity during the dark phase. This was abolished by HFD consumption, resulting in a decreased threshold for action potential generation during the day and therefore increased electrical activity at this phase. We propose this electrophysiological disturbance as a mechanism for the induction of abnormal daytime feeding, previously observed for HFD-fed animals, which might in turn contribute to the development of obesity. In addition, we provide an electrophysiological characteristic of DMH neurons with a separation into three anatomically and functionally distinct subpopulations, namely, the compact part, separating the structure into the ventral and dorsal divisions. Our study is the first to show electrophysiological complexity of the DMH with its sensitivity to diet and daily rhythms.
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Affiliation(s)
- Anna Magdalena Sanetra
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Krakow, Poland
| | - Katarzyna Palus-Chramiec
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Krakow, Poland
| | - Lukasz Chrobok
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Krakow, Poland.,School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, UK
| | - Marian Henryk Lewandowski
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Krakow, Poland
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Robertson RV, Crawford LS, Meylakh N, Macey PM, Macefield VG, Keay KA, Henderson LA. Regional hypothalamic, amygdala, and midbrain periaqueductal gray matter recruitment during acute pain in awake humans: A 7-Tesla functional magnetic resonance imaging study. Neuroimage 2022; 259:119408. [PMID: 35752415 DOI: 10.1016/j.neuroimage.2022.119408] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/28/2022] [Accepted: 06/21/2022] [Indexed: 10/17/2022] Open
Abstract
Over the past two decades, magnetic resonance imaging (MRI) studies have explored brain activation patterns during acute noxious stimuli. Whilst these human investigations have detailed changes in primarily cortical regions, they have generally not explored discrete changes within small brain areas that are critical in driving behavioural, autonomic, and endocrine responses to pain, such as within subregions of the hypothalamus, amygdala, and midbrain periaqueductal gray matter (PAG). Ultra-high field (7-Tesla) MRI provides enough signal-to-noise at high spatial resolutions to investigate activation patterns within these small brain regions during acute noxious stimulation in awake humans. In this study we used 7T functional MRI to concentrate on hypothalamic, amygdala, and PAG signal changes during acute noxious orofacial stimuli. Noxious heat stimuli were applied in three separate fMRI scans to three adjacent sites on the face in 16 healthy control participants (7 females). Images were processed using SPM12 and custom software, and blood oxygen level dependent signal changes within the hypothalamus, amygdala, and PAG assessed. We identified altered activity within eight unique subregions of the hypothalamus, four unique subregions of the amygdala, and a single region in the lateral PAG. Specifically, within the hypothalamus and amygdala, signal intensity largely decreased during noxious stimulation, and increased in the lateral PAG. Furthermore, we found sex-related differences in discrete regions of the hypothalamus and amygdala. This study reveals that the activity of discrete nuclei during acute noxious thermal stimulation in awake humans.
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Affiliation(s)
- Rebecca V Robertson
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, 2006, Australia
| | - Lewis S Crawford
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, 2006, Australia
| | - Noemi Meylakh
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, 2006, Australia
| | - Paul M Macey
- UCLA School of Nursing and Brain Research Institute, University of California, Los Angeles, CA 90095, USA
| | | | - Kevin A Keay
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, 2006, Australia
| | - Luke A Henderson
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, 2006, Australia.
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Nakamura K, Morrison SF. Central sympathetic network for thermoregulatory responses to psychological stress. Auton Neurosci 2021; 237:102918. [PMID: 34823147 DOI: 10.1016/j.autneu.2021.102918] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/05/2021] [Accepted: 11/13/2021] [Indexed: 11/16/2022]
Abstract
In mammals, many types of psychological stressors elicit a variety of sympathoexcitatory responses paralleling the classic fight-or-flight response to a threat to survival, including increased body temperature via brown adipose tissue thermogenesis and cutaneous vasoconstriction, and increased skeletal muscle blood flow via tachycardia and visceral vasoconstriction. Although these responses are usually supportive for stress coping, aberrant sympathetic responses to stress can lead to clinical issues in psychosomatic medicine. Sympathetic stress responses are mediated mostly by sympathetic premotor drives from the rostral medullary raphe region (rMR) and partly by those from the rostral ventrolateral medulla (RVLM). Hypothalamomedullary descending pathways from the dorsomedial hypothalamus (DMH) to the rMR and RVLM mediate important, stress-driven sympathoexcitatory transmission to the premotor neurons to drive the thermal and cardiovascular responses. The DMH also likely sends an excitatory input to the paraventricular hypothalamic nucleus to stimulate stress hormone release. Neurons in the DMH receive a stress-related excitation from the dorsal peduncular cortex and dorsal tenia tecta (DP/DTT) in the ventromedial prefrontal cortex. By connecting the corticolimbic emotion circuit to the central sympathetic and somatic motor systems, the DP/DTT → DMH pathway plays as the primary mediator of the psychosomatic signaling that drives a variety of sympathetic and behavioral stress responses. These brain regions together with other stress-related regions constitute a central neural network for physiological stress responses. This network model is relevant to understanding the central mechanisms by which stress and emotions affect autonomic regulations of homeostasis and to developing new therapeutic strategies for various stress-related disorders.
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Affiliation(s)
- Kazuhiro Nakamura
- Department of Integrative Physiology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
| | - Shaun F Morrison
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR 97239, USA
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Marins FR, Limborço-Filho M, Iddings JA, Xavier CH, Biancardi VC, Stern JE, Ramiro Diaz J, Oppenheimer SM, Filosa JA, Peliky Fontes MA. Tachycardia evoked from insular stroke in rats is dependent on glutamatergic neurotransmission in the dorsomedial hypothalamus. Eur J Neurol 2021; 28:3640-3649. [PMID: 34152065 DOI: 10.1111/ene.14987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND PURPOSE Damage to the insula results in cardiovascular complications. In rats, activation of N-methyl-d-aspartate receptors (NMDARs) in the intermediate region of the posterior insular cortex (iIC) results in sympathoexcitation, tachycardia and arterial pressure increases. Similarly, focal experimental hemorrhage at the iIC results in a marked sympathetic-mediated increase in baseline heart rate. The dorsomedial hypothalamic region (DMH) is critical for the integration of sympathetic-mediated tachycardic responses. Here, whether responses evoked from the iIC are dependent on a synaptic relay in the DMH was evaluated. METHODS Wistar rats were prepared for injections into the iIC and DMH. Anatomical (tracing combined with immunofluorescence) and functional experiments (cardiovascular and sympathetic recordings) were performed. RESULTS The iIC sends dense projections to the DMH. Approximately 50% of iIC neurons projecting to the DMH express NMDARs, NR1 subunit. Blockade of glutamatergic receptors in the DMH abolishes the cardiovascular and autonomic responses evoked by the activation of NMDARs in the iIC (change in mean arterial pressure 7 ± 1 vs. 1 ± 1 mmHg after DMH blockade; change in heart rate 28 ± 3 vs. 0 ± 3 bpm after DMH blockade; change in renal sympathetic nerve activity 23% ± 1% vs. -1% ± 4% after DMH blockade). Experimental hemorrhage at the iIC resulted in a marked tachycardia (change 89 ± 14 bpm) that was attenuated by 65% ± 5% (p = 0.0009) after glutamatergic blockade at the DMH. CONCLUSIONS The iIC-induced tachycardia is largely dependent upon a glutamatergic relay in the DMH. Our study reveals the presence of an excitatory glutamatergic pathway from the iIC to the DMH that may be involved in the cardiovascular alterations observed after insular stroke.
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Affiliation(s)
- Fernanda Ribeiro Marins
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Marcelo Limborço-Filho
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Carlos Henrique Xavier
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Brazil
| | - Vinicia C Biancardi
- Department of Anatomy, Physiology, and Pharmacology, Auburn University, and Center for Neurosciences Research Initiative, Auburn University, Auburn, AL, USA
| | - Javier E Stern
- Department of Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | | | - Stephen M Oppenheimer
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Tenorio-Lopes L, Kinkead R. Sex-Specific Effects of Stress on Respiratory Control: Plasticity, Adaptation, and Dysfunction. Compr Physiol 2021; 11:2097-2134. [PMID: 34107062 DOI: 10.1002/cphy.c200022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As our understanding of respiratory control evolves, we appreciate how the basic neurobiological principles of plasticity discovered in other systems shape the development and function of the respiratory control system. While breathing is a robust homeostatic function, there is growing evidence that stress disrupts respiratory control in ways that predispose to disease. Neonatal stress (in the form of maternal separation) affects "classical" respiratory control structures such as the peripheral O2 sensors (carotid bodies) and the medulla (e.g., nucleus of the solitary tract). Furthermore, early life stress disrupts the paraventricular nucleus of the hypothalamus (PVH), a structure that has emerged as a primary determinant of the intensity of the ventilatory response to hypoxia. Although underestimated, the PVH's influence on respiratory function is a logical extension of the hypothalamic control of metabolic demand and supply. In this article, we review the functional and anatomical links between the stress neuroendocrine axis and the medullary network regulating breathing. We then present the persistent and sex-specific effects of neonatal stress on respiratory control in adult rats. The similarities between the respiratory phenotype of stressed rats and clinical manifestations of respiratory control disorders such as sleep-disordered breathing and panic attacks are remarkable. These observations are in line with the scientific consensus that the origins of adult disease are often found among developmental and biological disruptions occurring during early life. These observations bring a different perspective on the structural hierarchy of respiratory homeostasis and point to new directions in our understanding of the etiology of respiratory control disorders. © 2021 American Physiological Society. Compr Physiol 11:1-38, 2021.
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Affiliation(s)
- Luana Tenorio-Lopes
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, Alberta, Canada
| | - Richard Kinkead
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Quebec, Canada
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Henderson LA, Macefield VG. The role of the dorsomedial and ventromedial hypothalamus in regulating behaviorally coupled and resting autonomic drive. HANDBOOK OF CLINICAL NEUROLOGY 2021; 180:187-200. [PMID: 34225929 DOI: 10.1016/b978-0-12-820107-7.00012-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nearly a century ago it was reported that stimulation of the hypothalamus could evoke profound behavioral state changes coupled with altered autonomic function. Since these initial observations, further studies in animals have revealed that two hypothalamic regions-the dorsomedial and ventromedial hypothalamic nuclei-are critical for numerous behaviors, including those in response to psychological stressors. These behaviors are coupled with changes in autonomic functions, such as altered blood pressure, heart rate, sympathetic nerve activity, resetting of the baroreflex and changes in pituitary function. There is also growing evidence that these two hypothalamic regions play a critical role in thermogenesis, and suggestions they could also be responsible for the hypertension associated with obesity. The aim of this chapter is to review the anatomy, projection patterns, and function of the dorsomedial and ventromedial hypothalamus with a particular focus on their role in autonomic regulation. While most of what is known about these two hypothalamic regions is derived from laboratory animal experiments, recent human studies will also be explored. Finally, we will describe recent human brain imaging studies that provide evidence of a role for these hypothalamic regions in setting resting sympathetic drive and their potential role in conditions such as hypertension.
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Affiliation(s)
- Luke A Henderson
- Department of Anatomy & Histology, Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia.
| | - Vaughan G Macefield
- Baker Heart & Diabetes Institute, Melbourne, VIC, Australia; Department of Anatomy and Physiology, University of Melbourne, Melbourne, VIC, Australia
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NejadShahrokhAbadi R, Zangouei AS, Mohebbati R, Shafei MN. Determining the cardiovascular effects of nitric oxide in the dorsolateral Periaqueductal Gray (dlPAG) in anaesthetised rats. J Taibah Univ Med Sci 2020; 15:502-508. [PMID: 33318742 PMCID: PMC7715464 DOI: 10.1016/j.jtumed.2020.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE The dorsolateral periaqueductal gray (dlPAG) is an area located in the brain stem that performs a host of functions including cardiovascular regulation. Owing to the presence of nitric oxide (NO) in this area, we investigated its effect on the cardiovascular system. METHODS We divided rats into four groups: 1) control; 2) l-arginine (L-Arg, a precursor for nitric oxide, 60 nmol); 3) l-NAME (N omega-nitro-l-arginine methyl ester, a nitric oxide synthase inhibitor, 90 nmol); and 4) sodium nitroprusside (SNP, a nitric oxide donor, 27 nmol). After anaesthesia, the rats were mounted on a stereotaxic apparatus and the drugs were microinjected into the dlPAG. Cardiovascular parameters were continuously recorded by a PowerLab system connected to the cannulated femoral artery via a pressure transducer. The changes (Δ) of systolic blood pressure (SBP), mean arterial pressure (MAP), and heart rate (HR) were calculated at different times as compared to the control group. RESULTS In the l-NAME group, the ΔSBP, ΔMAP, and ΔHR were not significantly affected compared to the control group. In the L-Arg group, ΔSBP and ΔMAP increased; however, only SBP showed a significant increase compared to the control group. In the SNP group, SBP and MAP were significantly affected in comparison to the controls. Additionally, ΔHR decreased in both L-Arg and SNP, but was only significant in L-Arg. CONCLUSION Our study showed that NO of dlPAG has a pressor effect and attenuates baroreflex bradycardia. However, its pressor effect is more significant.
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Affiliation(s)
| | - Amir Sadra Zangouei
- Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Reza Mohebbati
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Naser Shafei
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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11
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Ventromedial medullary pathway mediating cardiac responses evoked from periaqueductal gray. Auton Neurosci 2020; 228:102716. [PMID: 32882606 DOI: 10.1016/j.autneu.2020.102716] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/23/2020] [Accepted: 08/07/2020] [Indexed: 11/20/2022]
Abstract
Periaqueductal gray (PAG) is a midbrain region that projects to areas controlling behavioral and autonomic outputs and is involved in the behavioral and physiological components of defense reactions. Since Raphe Pallidus (RPa) is a medial medullary region comprising sympathetic premotor neurons governing heart function, it is worth considering the PAG-RPa path. We assessed: i) whether PAG projects to RPa; ii) the amplitude of cardiac responses evoked from PAG; iii) whether cardiovascular responses evoked from PAG rely on RPa. Experiments conducted in Wistar rats (±300 g) were approved by Ethics Committee CEUA-UFG (092/18). Firstly, (n = 3), monosynaptic retrograde tracer Retrobeads was injected into RPa; PAG slices were analyzed. Other two groups (n = 6 each) were anesthetized with urethane (1.4 g/kg) and chloralose (120 mg/kg) and underwent craniotomy, tracheostomy, catheterization of femoral artery and vein and of cardiac left ventricle. In one group, we injected the GABAA receptor antagonist, bicuculline methiodide (BMI - 40 pmol/100 nL) into lateral/dorsolateral PAG. Another group was injected (100 nL) with the GABAA receptor agonist muscimol (20 mM) into RPa, 20 min before BMI into PAG. The results were: i) retrogradely labelled neurons were found in PAG; ii) PAG activation by BMI caused positive chronotropism and inotropism, which were accompanied by afterload increases; iii) RPa inhibition with Muscimol reduced heart rate, arterial and ventricular pressures; iv) the subsequent PAG activation still increased arterial pressure, cardiac chronotropy and inotropy, but these responses were significantly attenuated. In conclusion, PAG activation increases cardiac chronotropy and inotropy, and these responses seem to rely on a direct pathway reaching ventromedial medullary RPa neurons.
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12
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Rietema SE, Hawken PAR, Scott CJ, Lehman MN, Martin GB, Smith JT. Arcuate nucleus kisspeptin response to increased nutrition in rams. Reprod Fertil Dev 2020; 31:1682-1691. [PMID: 31511141 DOI: 10.1071/rd19063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 06/16/2019] [Indexed: 11/23/2022] Open
Abstract
Rams respond to acute nutritional supplementation by increasing the frequency of gonadotrophin-releasing hormone (GnRH) pulses. Kisspeptin neurons may mediate the effect of environmental cues on GnRH secretion, so we tested whether the ram response to nutrition involves activation of kisspeptin neurons in the arcuate nucleus (ARC), namely kisspeptin, neurokin B, dynorphin (KNDy) neurons. Rams were given extra lupin grain with their normal ration. Blood was sampled before feeding, and continued until animals were killed for collection of brain tissue at 2 or 11h after supplementation. In supplemented rams, LH pulse frequency increased after feeding, whereas control animals showed no change. Within the caudal ARC, there were more kisspeptin neurons in supplemented rams than in controls and a higher proportion of kisspeptin cells coexpressed Fos, regardless of the time the rams were killed. There were more Fos cells in the mid-ARC and mid-dorsomedial hypothalamus of the supplemented compared with control rams. No effect of nutrition was found on kisspeptin expression in the rostral or mid-ARC, or on GnRH expression in the preoptic area. Kisspeptin neurons in the caudal ARC appear to mediate the increase in GnRH and LH production due to acute nutritional supplementation, supporting the hypothesised role of the KNDy neurons as the pulse generator for GnRH.
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Affiliation(s)
- S E Rietema
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - P A R Hawken
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - C J Scott
- School of Biomedical Sciences, Charles Sturt University, Boorooma Street, Wagga Wagga, NSW 2678, Australia
| | - M N Lehman
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, PO Box 5190, Kent, OH 44242-0001, USA
| | - G B Martin
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - J T Smith
- The School of Human Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia; and Corresponding author.
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Kono Y, Yokota S, Fukushi I, Arima Y, Onimaru H, Okazaki S, Takeda K, Yazawa I, Yoshizawa M, Hasebe Y, Koizumi K, Pokorski M, Toda T, Sugita K, Okada Y. Structural and functional connectivity from the dorsomedial hypothalamus to the ventral medulla as a chronological amplifier of sympathetic outflow. Sci Rep 2020; 10:13325. [PMID: 32770006 PMCID: PMC7414200 DOI: 10.1038/s41598-020-70234-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/27/2020] [Indexed: 12/15/2022] Open
Abstract
Psychological stress activates the hypothalamus, augments the sympathetic nervous output, and elevates blood pressure via excitation of the ventral medullary cardiovascular regions. However, anatomical and functional connectivity from the hypothalamus to the ventral medullary cardiovascular regions has not been fully elucidated. We investigated this issue by tract-tracing and functional imaging in rats. Retrograde tracing revealed the rostral ventrolateral medulla was innervated by neurons in the ipsilateral dorsomedial hypothalamus (DMH). Anterograde tracing showed DMH neurons projected to the ventral medullary cardiovascular regions with axon terminals in contiguity with tyrosine hydroxylase-immunoreactive neurons. By voltage-sensitive dye imaging, dynamics of ventral medullary activation evoked by electrical stimulation of the DMH were analyzed in the diencephalon-lower brainstem-spinal cord preparation of rats. Although the activation of the ventral medulla induced by single pulse stimulation of the DMH was brief, tetanic stimulation caused activation of the DMH sustained into the post-stimulus phase, resulting in delayed recovery. We suggest that prolonged excitation of the DMH, which is triggered by tetanic electrical stimulation and could also be triggered by psychological stress in a real life, induces further prolonged excitation of the medullary cardiovascular networks, and could contribute to the pathological elevation of blood pressure. The connectivity from the DMH to the medullary cardiovascular networks serves as a chronological amplifier of stress-induced sympathetic excitation. This notion will be the anatomical and pathophysiological basis to understand the mechanisms of stress-induced sustained augmentation of sympathetic activity.
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Affiliation(s)
- Yosuke Kono
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan.,Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan
| | - Shigefumi Yokota
- Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo, Shimane, 693-8501, Japan
| | - Isato Fukushi
- Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan.,Faculty of Health Sciences, Uekusa Gakuen University, Chiba, 264-0007, Japan
| | - Yosuke Arima
- Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo, Shimane, 693-8501, Japan
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Shinagawa, Tokyo, 142-8555, Japan
| | - Shuntaro Okazaki
- Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama, 359-1192, Japan
| | - Kotaro Takeda
- Faculty of Rehabilitation, School of Healthcare, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Itaru Yazawa
- Global Research Center for Innovative Life Science, Hoshi University, Shinagawa, Tokyo, 142-8501, Japan
| | - Masashi Yoshizawa
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan.,Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan
| | - Yohei Hasebe
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan.,Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan
| | - Keiichi Koizumi
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan
| | | | - Takako Toda
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan
| | - Kanji Sugita
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan
| | - Yasumasa Okada
- Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan.
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14
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Differences in regional grey matter volume of the brain are related to mean blood pressure and muscle sympathetic nerve activity in normotensive humans. J Hypertens 2020; 38:303-313. [DOI: 10.1097/hjh.0000000000002243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Brouillard C, Carrive P, Camus F, Bénoliel JJ, Sévoz-Couche C. Vulnerability to stress consequences induced by repeated social defeat in rats: Contribution of the angiotensin II type 1 receptor in cardiovascular alterations associated to low brain derived neurotrophic factor. Eur J Pharmacol 2019; 861:172595. [DOI: 10.1016/j.ejphar.2019.172595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 08/02/2019] [Accepted: 08/07/2019] [Indexed: 01/17/2023]
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16
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Schmitt O, Eipert P, Schwanke S, Lessmann F, Meinhardt J, Beier J, Kadir K, Karnitzki A, Sellner L, Klünker AC, Ruß F, Jenssen J. Connectome verification: inter-rater and connection reliability of tract-tracing-based intrinsic hypothalamic connectivity. Brief Bioinform 2019; 20:1944-1955. [PMID: 29897426 DOI: 10.1093/bib/bby048] [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: 02/20/2018] [Revised: 05/09/2018] [Indexed: 11/12/2022] Open
Abstract
MOTIVATION Structural connectomics supports understanding aspects of neuronal dynamics and brain functions. Conducting metastudies of tract-tracing publications is one option to generate connectome databases by collating neuronal connectivity data. Meanwhile, it is a common practice that the neuronal connections and their attributes of such retrospective data collations are extracted from tract-tracing publications manually by experts. As the description of tract-tracing results is often not clear-cut and the documentation of interregional connections is not standardized, the extraction of connectivity data from tract-tracing publications could be complex. This might entail that different experts interpret such non-standardized descriptions of neuronal connections from the same publication in variable ways. Hitherto, no investigation is available that determines the variability of extracted connectivity information from original tract-tracing publications. A relatively large variability of connectivity information could produce significant misconstructions of adjacency matrices with faults in network and graph analyzes. The objective of this study is to investigate the inter-rater and inter-observation variability of tract-tracing-based documentations of neuronal connections. To demonstrate the variability of neuronal connections, data of 16 publications which describe neuronal connections of subregions of the hypothalamus have been assessed by way of example. RESULTS A workflow is proposed that allows detecting variability of connectivity at different steps of data processing in connectome metastudies. Variability between three blinded experts was found by comparing the connection information in a sample of 16 publications that describe tract-tracing-based neuronal connections in the hypothalamus. Furthermore, observation scores, matrix visualizations of discrepant connections and weight variations in adjacency matrices are analyzed. AVAILABILITY The resulting data and software are available at http://neuroviisas.med.uni-rostock.de/neuroviisas.shtml.
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Affiliation(s)
- Oliver Schmitt
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Peter Eipert
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Sebastian Schwanke
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Felix Lessmann
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Jennifer Meinhardt
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Julia Beier
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Kanar Kadir
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Adrian Karnitzki
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Linda Sellner
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Ann-Christin Klünker
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Frauke Ruß
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
| | - Jörg Jenssen
- Department of Anatomy, University of Rostock, Gertrudenstr. 9, 18057 Rostock, Germany
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17
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A time to fight: Circadian control of aggression and associated autonomic support. Auton Neurosci 2018; 217:35-40. [PMID: 30704973 DOI: 10.1016/j.autneu.2018.12.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 02/06/2023]
Abstract
The central circadian clock, located in the suprachiasmatic nucleus of the mammalian hypothalamus (SCN), regulates daily behavioral rhythms including the temporal propensity for aggressive behavior. Such aggression propensity rhythms are regulated by a functional circuit from the SCN to neurons that drive attack behavior in the ventromedial hypothalamus (VMH), via a relay in the subparaventricular zone (SPZ). In addition to this pathway, the SCN also regulates sleep-wake and locomotor activity rhythms, via the SPZ, in a circuit to the dorsomedial hypothalamus (DMH), a structure that is also known to play a key role in autonomic function and the sympathetic "fight-or-flight" response (which prepares the body for action in stressful situations such as an agonistic encounter). While the autonomic nervous system is known to be under pronounced circadian control, it is less apparent how such autonomic rhythms and their underlying circuitry may support the temporal propensity for aggressive behavior. Additionally, it is unclear how circadian and autonomic dysfunction may contribute to aberrant social and emotional behavior, such as agitation and aggression. Here we review the literature concerning interactions between the circadian and autonomic systems and aggression, and we discuss the implications of these relationships for human neural and behavioral pathologies.
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18
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Derera ID, Smith KC, Smith BN. Altered A-type potassium channel function in the nucleus tractus solitarii in acquired temporal lobe epilepsy. J Neurophysiol 2018; 121:177-187. [PMID: 30517061 DOI: 10.1152/jn.00556.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is among the leading causes of death in people with epilepsy. Individuals with temporal lobe epilepsy (TLE) have a high risk for SUDEP because the seizures are often medically intractable. Neurons in the nucleus tractus solitarii (NTS) have been implicated in mouse models of SUDEP and play a critical role in modulating cardiorespiratory and autonomic output. Increased neuronal excitability of inhibitory, GABAergic neurons in the NTS develops during epileptogenesis, and NTS dysfunction has been implicated in mouse models of SUDEP. In this study we used the pilocarpine-induced status epilepticus model of TLE (i.e., pilo-SE mice) to investigate the A-type voltage-gated K+ channel as a potential contributor to increased excitability in GABAergic NTS neurons during epileptogenesis. Compared with age-matched control mice, pilo-SE mice displayed an increase in spontaneous action potential frequency and half-width 9-12 wk after treatment. Activity of GABAergic NTS neurons from pilo-SE mice showed less sensitivity to 4-aminopyridine. Correspondingly, reduced A-type K+ current amplitude was detected in these neurons, with no change in activation or inactivation kinetics. No changes were observed in Kv4.1, Kv4.2, Kv4.3, KChIP1, KChIP3, or KChIP4 mRNA expression. These changes contribute to the increased excitability in GABAergic NTS neurons that develops in TLE and may provide insight into potential mechanisms contributing to the increased risk for cardiorespiratory collapse and SUDEP in this model. NEW & NOTEWORTHY Sudden unexpected death in epilepsy (SUDEP) is a leading cause of death in epilepsy, and dysfunction in central autonomic neurons may play a role. In a mouse model of acquired epilepsy, GABAergic neurons in the nucleus tractus solitarii developed a reduced amplitude of the A-type current, which contributes to the increased excitability seen in these neurons during epileptogenesis. Neuronal excitability changes in inhibitory central vagal circuitry may increase the risk for cardiorespiratory collapse and SUDEP.
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Affiliation(s)
- Isabel D Derera
- Department of Physiology, College of Medicine, University of Kentucky , Lexington, Kentucky
| | - Katalin Cs Smith
- Department of Physiology, College of Medicine, University of Kentucky , Lexington, Kentucky.,Department of Neuroscience, College of Medicine, University of Kentucky , Lexington, Kentucky
| | - Bret N Smith
- Department of Physiology, College of Medicine, University of Kentucky , Lexington, Kentucky.,Department of Neuroscience, College of Medicine, University of Kentucky , Lexington, Kentucky.,Epilepsy Research Center, University of Kentucky , Lexington, Kentucky
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19
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Abreu AR, Molosh AI, Johnson PL, Shekhar A. Role of medial hypothalamic orexin system in panic, phobia and hypertension. Brain Res 2018; 1731:145942. [PMID: 30205108 DOI: 10.1016/j.brainres.2018.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 09/04/2018] [Accepted: 09/06/2018] [Indexed: 12/11/2022]
Abstract
Orexin has been implicated in a number of physiological functions, including arousal, regulation of sleep, energy metabolism, appetitive behaviors, stress, anxiety, fear, panic, and cardiovascular control. In this review, we will highlight research focused on orexin system in the medial hypothalamic regions of perifornical (PeF) and dorsomedial hypothalamus (DMH), and describe the role of this hypothalamic neuropeptide in the behavioral expression of panic and consequent fear and avoidance responses, as well as sympathetic regulation and possible development of chronic hypertension. We will also outline recent data highlighting the clinical potential of single and dual orexin receptor antagonists for neuropsychiatric conditions including panic, phobia, and cardiovascular conditions, such as in hypertension.
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Affiliation(s)
- Aline R Abreu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrei I Molosh
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Philip L Johnson
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anantha Shekhar
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Clinical and Translational Sciences Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
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20
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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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21
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Xavier CH, Mendonça MM, Marins FR, da Silva ES, Ianzer D, Colugnati DB, Pedrino GR, Fontes MAP. Stating asymmetry in neural pathways: methodological trends in autonomic neuroscience. Int J Neurosci 2018; 128:1078-1085. [DOI: 10.1080/00207454.2018.1473396] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Carlos Henrique Xavier
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Michelle Mendanha Mendonça
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Fernanda Ribeiro Marins
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Elder Sales da Silva
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Danielle Ianzer
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Diego Basile Colugnati
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Gustavo Rodrigues Pedrino
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Marco Antonio Peliky Fontes
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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22
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Camargo-Silva G, Turones LC, da Cruz KR, Gomes KP, Mendonça MM, Nunes A, de Jesus IG, Colugnati DB, Pansani AP, Pobbe RLH, Santos R, Fontes MAP, Guatimosim S, de Castro CH, Ianzer D, Ferreira RN, Xavier CH. Ghrelin potentiates cardiac reactivity to stress by modulating sympathetic control and beta-adrenergic response. Life Sci 2018; 196:84-92. [PMID: 29366747 DOI: 10.1016/j.lfs.2018.01.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/10/2018] [Accepted: 01/18/2018] [Indexed: 02/07/2023]
Abstract
Prior evidence indicates that ghrelin is involved in the integration of cardiovascular functions and behavioral responses. Ghrelin actions are mediated by the growth hormone secretagogue receptor subtype 1a (GHS-R1a), which is expressed in peripheral tissues and central areas involved in the control of cardiovascular responses to stress. AIMS In the present study, we assessed the role of ghrelin - GHS-R1a axis in the cardiovascular reactivity to acute emotional stress in rats. MAIN METHODS AND KEY FINDINGS Ghrelin potentiated the tachycardia evoked by restraint and air jet stresses, which was reverted by GHS-R1a blockade. Evaluation of the autonomic balance revealed that the sympathetic branch modulates the ghrelin-evoked positive chronotropy. In isolated hearts, the perfusion with ghrelin potentiated the contractile responses caused by stimulation of the beta-adrenergic receptor, without altering the amplitude of the responses evoked by acetylcholine. Experiments in isolated cardiomyocytes revealed that ghrelin amplified the increases in calcium transient changes evoked by isoproterenol. SIGNIFICANCE Taken together, our results indicate that the Ghrelin-GHS-R1a axis potentiates the magnitude of stress-evoked tachycardia by modulating the autonomic nervous system and peripheral mechanisms, strongly relying on the activation of cardiac calcium transient and beta-adrenergic receptors.
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Affiliation(s)
- Gabriel Camargo-Silva
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Larissa Córdova Turones
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Kellen Rosa da Cruz
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Karina Pereira Gomes
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Michelle Mendanha Mendonça
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Allancer Nunes
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Itamar Guedes de Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Diego Basile Colugnati
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Aline Priscila Pansani
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Roger Luis Henschel Pobbe
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Robson Santos
- National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | | | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | - Carlos Henrique de Castro
- Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | - Danielle Ianzer
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil
| | - Reginaldo Nassar Ferreira
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil
| | - Carlos Henrique Xavier
- Laboratory of Cardiovascular Physiology and Therapeutics, Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiania, GO, Brazil; National Institute of Science and Technology Nanobiopharmaceutics (INCT NanoBioFar), Brazil.
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23
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Fontes MAP, Vaz GC, Cardoso TZD, de Oliveira MF, Campagnole-Santos MJ, Dos Santos RAS, Sharma NM, Patel KP, Frézard F. GABA-containing liposomes: neuroscience applications and translational perspectives for targeting neurological diseases. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2017; 14:781-788. [PMID: 29278747 DOI: 10.1016/j.nano.2017.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/27/2017] [Accepted: 12/10/2017] [Indexed: 11/28/2022]
Abstract
There are multiple challenges for neuropharmacology in the future. Undoubtedly, one of the greatest challenges is the development of strategies for pharmacological targeting of specific brain regions for treatment of diseases. GABA is the main inhibitory neurotransmitter in the central nervous system, and dysfunction of GABAergic mechanisms is associated with different neurological conditions. Liposomes are lipid vesicles that are able to encapsulate chemical compounds and are used for chronic drug delivery. This short review reports our experience with the development of liposomes for encapsulation and chronic delivery of GABA to sites within the brain. Directions for future research regarding the efficacy and practical use of GABA-containing liposomes for extended periods of time as well as understanding and targeting neurological conditions are discussed.
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Affiliation(s)
| | - Gisele Cristiane Vaz
- Department of Physiology & Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | | | | | | | - Neeru M Sharma
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Frédéric Frézard
- Department of Physiology & Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil.
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24
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Barman SM, Yates BJ. Deciphering the Neural Control of Sympathetic Nerve Activity: Status Report and Directions for Future Research. Front Neurosci 2017; 11:730. [PMID: 29311801 PMCID: PMC5743742 DOI: 10.3389/fnins.2017.00730] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/14/2017] [Indexed: 12/15/2022] Open
Abstract
Sympathetic nerve activity (SNA) contributes appreciably to the control of physiological function, such that pathological alterations in SNA can lead to a variety of diseases. The goal of this review is to discuss the characteristics of SNA, briefly review the methodology that has been used to assess SNA and its control, and to describe the essential role of neurophysiological studies in conscious animals to provide additional insights into the regulation of SNA. Studies in both humans and animals have shown that SNA is rhythmic or organized into bursts whose frequency varies depending on experimental conditions and the species. These rhythms are generated by brainstem neurons, and conveyed to sympathetic preganglionic neurons through several pathways, including those emanating from the rostral ventrolateral medulla. Although rhythmic SNA is present in decerebrate animals (indicating that neurons in the brainstem and spinal cord are adequate to generate this activity), there is considerable evidence that a variety of supratentorial structures including the insular and prefrontal cortices, amygdala, and hypothalamic subnuclei provide inputs to the brainstem regions that regulate SNA. It is also known that the characteristics of SNA are altered during stress and particular behaviors such as the defense response and exercise. While it is a certainty that supratentorial structures contribute to changes in SNA during these behaviors, the neural underpinnings of the responses are yet to be established. Understanding how SNA is modified during affective responses and particular behaviors will require neurophysiological studies in awake, behaving animals, including those that entail recording activity from neurons that generate SNA. Recent studies have shown that responses of neurons in the central nervous system to most sensory inputs are context-specific. Future neurophysiological studies in conscious animals should also ascertain whether this general rule also applies to sensory signals that modify SNA.
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Affiliation(s)
- Susan M Barman
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Bill J Yates
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
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Li TL, Chen JYS, Huang SC, Dai YWE, Hwang LL. Cardiovascular pressor effects of orexins in the dorsomedial hypothalamus. Eur J Pharmacol 2017; 818:343-350. [PMID: 29104046 DOI: 10.1016/j.ejphar.2017.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 10/27/2017] [Accepted: 11/01/2017] [Indexed: 10/18/2022]
Abstract
Orexins are important regulators of cardiovascular functions in various physiological and pathological conditions. The dorsomedial hypothalamus (DMH), an essential mediator of cardiovascular responses to stress, contains dense orexinergic innervations and receptors. We examined whether orexins can regulate cardiovascular functions through their actions in the DMH in anesthetized rats. An intra-DMH injection of orexin A (30pmol) produced elevation of arterial pressure and heart rate. Orexin A-sensitive sites were located within or immediately adjacent to the DMH and larger responses were induced at the compact part of the dorsomedial hypothalamic nucleus. Orexin A-induced responses were attenuated by intra-DMH pretreatment with an orexin receptor 1 (OX1R) antagonist, SB-334867 (15nmol) (17.7 ± 2.8 vs. 5.2 ± 1.0mmHg; 54.6 ± 10.0 vs. 22.8 ± 7.4 beats/min). Intra-DMH applied [Ala11,D-Leu15]-orexin B (300 pmol), an orexin receptor 2 (OX2R) agonist, elicited cardiovascular responses mimicking the responses of orexin A, except for a smaller pressor response (7.4 ± 1.7 vs. 16.4 ± 1.8mmHg). In a series of experiment, effects of orexin B (100pmol) and then orexin A (30pmol), were examined at a same site. Two patterns of responses were observed in 12 intra-DMH sites: (1) both orexin A and B (9 sites), and (2) only orexin A (3 sites) induced cardiovascular responses, respectively suggesting OX1R/OX2R-mediated and OX1R-predominant mechanisms. In conclusion, orexins regulated cardiovascular functions through OX1R/OX2R- or OX1R-mediated mechanisms at different locations in the DMH.
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Affiliation(s)
- Tzu-Ling Li
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan.
| | - Jennifer Y S Chen
- School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan.
| | - Shang-Cheng Huang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan.
| | - Yu-Wen E Dai
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan.
| | - Ling-Ling Hwang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan; Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan.
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Asymmetric sympathetic output: The dorsomedial hypothalamus as a potential link between emotional stress and cardiac arrhythmias. Auton Neurosci 2017; 207:22-27. [DOI: 10.1016/j.autneu.2017.01.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/03/2017] [Accepted: 01/10/2017] [Indexed: 12/20/2022]
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Functional Neuroplasticity in the Nucleus Tractus Solitarius and Increased Risk of Sudden Death in Mice with Acquired Temporal Lobe Epilepsy. eNeuro 2017; 4:eN-NWR-0319-17. [PMID: 29085908 PMCID: PMC5661358 DOI: 10.1523/eneuro.0319-17.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 12/23/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in individuals with refractory acquired epilepsy. Cardiorespiratory failure is the most likely cause in most cases, and central autonomic dysfunction has been implicated as a contributing factor to SUDEP. Neurons of the nucleus tractus solitarius (NTS) in the brainstem vagal complex receive and integrate vagally mediated information regarding cardiorespiratory and other autonomic functions, and GABAergic inhibitory NTS neurons play an essential role in modulating autonomic output. We assessed the activity of GABAergic NTS neurons as a function of epilepsy development in the pilocarpine-induced status epilepticus (SE) model of temporal lobe epilepsy (TLE). Compared with age-matched controls, mice that survived SE had significantly lower survival rates by 150 d post-SE. GABAergic NTS neurons from mice that survived SE displayed a glutamate-dependent increase in spontaneous action potential firing rate by 12 wks post-SE. Increased spontaneous EPSC frequency was also detected, but vagal afferent synaptic release properties were unaltered, suggesting that an increase in glutamate release from central neurons developed in the NTS after SE. Our results indicate that long-term changes in glutamate release and activity of GABAergic neurons emerge in the NTS in association with epileptogenesis. These changes might contribute to increased risk of cardiorespiratory dysfunction and sudden death in this model of TLE.
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Shi Z, Madden CJ, Brooks VL. Arcuate neuropeptide Y inhibits sympathetic nerve activity via multiple neuropathways. J Clin Invest 2017. [PMID: 28628036 PMCID: PMC5490747 DOI: 10.1172/jci92008] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Obesity increases sympathetic nerve activity (SNA) via activation of proopiomelanocortin neurons in the arcuate nucleus (ArcN), and this action requires simultaneous withdrawal of tonic neuropeptide Y (NPY) sympathoinhibition. However, the sites and neurocircuitry by which NPY decreases SNA are unclear. Here, using designer receptors exclusively activated by designer drugs (DREADDs) to selectively activate or inhibit ArcN NPY neurons expressing agouti-related peptide (AgRP) in mice, we have demonstrated that this neuronal population tonically suppresses splanchnic SNA (SSNA), arterial pressure, and heart rate via projections to the paraventricular nucleus (PVN) and dorsomedial hypothalamus (DMH). First, we found that ArcN NPY/AgRP fibers closely appose PVN and DMH presympathetic neurons. Second, nanoinjections of NPY or an NPY receptor Y1 (NPY1R) antagonist into PVN or DMH decreased or increased SSNA, respectively. Third, blockade of DMH NPY1R reversed the sympathoinhibition elicited by selective, DREADD-mediated activation of ArcN NPY/AgRP neurons. Finally, stimulation of ArcN NPY/AgRP terminal fields in the PVN and DMH decreased SSNA. Considering that chronic obesity decreases ArcN NPY content, we propose that the ArcN NPY neuropathway to the PVN and DMH is pivotal in obesity-induced elevations in SNA.
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Affiliation(s)
- Zhigang Shi
- Department of Physiology and Pharmacology and
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, USA
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McCall AA, Miller DM, Yates BJ. Descending Influences on Vestibulospinal and Vestibulosympathetic Reflexes. Front Neurol 2017; 8:112. [PMID: 28396651 PMCID: PMC5366978 DOI: 10.3389/fneur.2017.00112] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/09/2017] [Indexed: 12/15/2022] Open
Abstract
This review considers the integration of vestibular and other signals by the central nervous system pathways that participate in balance control and blood pressure regulation, with an emphasis on how this integration may modify posture-related responses in accordance with behavioral context. Two pathways convey vestibular signals to limb motoneurons: the lateral vestibulospinal tract and reticulospinal projections. Both pathways receive direct inputs from the cerebral cortex and cerebellum, and also integrate vestibular, spinal, and other inputs. Decerebration in animals or strokes that interrupt corticobulbar projections in humans alter the gain of vestibulospinal reflexes and the responses of vestibular nucleus neurons to particular stimuli. This evidence shows that supratentorial regions modify the activity of the vestibular system, but the functional importance of descending influences on vestibulospinal reflexes acting on the limbs is currently unknown. It is often overlooked that the vestibulospinal and reticulospinal systems mainly terminate on spinal interneurons, and not directly on motoneurons, yet little is known about the transformation of vestibular signals that occurs in the spinal cord. Unexpected changes in body position that elicit vestibulospinal reflexes can also produce vestibulosympathetic responses that serve to maintain stable blood pressure. Vestibulosympathetic reflexes are mediated, at least in part, through a specialized group of reticulospinal neurons in the rostral ventrolateral medulla that project to sympathetic preganglionic neurons in the spinal cord. However, other pathways may also contribute to these responses, including those that dually participate in motor control and regulation of sympathetic nervous system activity. Vestibulosympathetic reflexes differ in conscious and decerebrate animals, indicating that supratentorial regions alter these responses. However, as with vestibular reflexes acting on the limbs, little is known about the physiological significance of descending control of vestibulosympathetic pathways.
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Affiliation(s)
- Andrew A McCall
- Department of Otolaryngology, University of Pittsburgh School of Medicine , Pittsburgh, PA , USA
| | - Derek M Miller
- Department of Otolaryngology, University of Pittsburgh School of Medicine , Pittsburgh, PA , USA
| | - Bill J Yates
- Department of Otolaryngology, University of Pittsburgh School of Medicine , Pittsburgh, PA , USA
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Moura Santos D, Ribeiro Marins F, Limborço-Filho M, de Oliveira ML, Hamamoto D, Xavier CH, Moreira FA, Santos RAS, Campagnole-Santos MJ, Peliky Fontes MA. Chronic overexpression of angiotensin-(1-7) in rats reduces cardiac reactivity to acute stress and dampens anxious behavior. Stress 2017; 20:189-196. [PMID: 28288545 DOI: 10.1080/10253890.2017.1296949] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Angiotensin II (Ang II) acts as a pro-stress hormone, while other evidence indicates that angiotensin-(1-7) [Ang-(1-7)] attenuates physiological responses to emotional stress. To further test this hypothesis, in groups of 5-6 rats we evaluated autonomic, cardiovascular and behavioral parameters in male Sprague-Dawley (SD) and transgenic TGR(A1-7)3292 (TG) rats chronically overexpressing Ang-(1-7). Compared to SD rats, TG rats showed reduced baseline heart rate (HR; SD 380 ± 16 versus TG 329 ± 9 beats per minute (bpm), mean ± standard error of mean, p < .05) and renal sympathetic discharge (SD 138 ± 4 versus TG 117 ± 5 spikes/second, p < .05). TG rats had an attenuated tachycardic response to acute air-puff stress (ΔHR: SD 51 ± 20 versus TG 1 ± 3 bpm; p < .05), which was reversed by intracerebroventricular injection of the Mas receptor antagonist, A-779 (ΔHR: SD 51 ± 20 versus TG 63 ± 15 bpm). TG rats showed less anxious behavior on the elevated plus maze, as revealed by more entries into open arms (SD 2 ± 2 versus TG 47 ± 5% relative to total entries; p < .05), and more time spent in the open arms (SD 5 ± 4 versus TG 53 ± 9% relative to total time, p < .05). By contrast with SD rats, diazepam (1.5 mg/kg, intraperitoneally) did not further reduce anxious behavior in TG rats, indicating a ceiling anxiolytic effect of Ang-(1-7) overexpression. Ang-(1-7) concentrations in hypothalamus and plasma, measured by mass spectrometry were two- and three-fold greater, respectively, in TG rats than in SD rats. Hence, increased endogenous Ang-(1-7) levels in TG rats diminishes renal sympathetic outflow and attenuates cardiac reactivity to emotional stress, which may be via central Mas receptors, and reduces anxious behavior. Lay summaryWe used a genetically modified rat model that produces above normal amounts of a peptide hormone called angiotensin-(1-7) to test whether this peptide can reduce some of the effects of stress. We found that angiotensin-(1-7), acting in the brain, can reduce anxiety and reduce the increase in heart rate associated with emotional stress. These findings may provide a lead for design of new drugs to reduce stress.
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Affiliation(s)
- Danielle Moura Santos
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Fernanda Ribeiro Marins
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Marcelo Limborço-Filho
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Marilene Luzia de Oliveira
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | | | - Carlos Henrique Xavier
- c Department of Physiology , Institute of Biological Sciences, Federal University of Goiás , Goiás , Brazil Goiânia
| | - Fabrício Araújo Moreira
- d Department of Pharmacology , Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Robson Augusto Souza Santos
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
- b Alamantec/LABFAR , Minas Gerais , Brazil
- e Institute of Cardiology , University Foundation of Cardiology , Rio Grande do Sul , Brazil
| | - Maria José Campagnole-Santos
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
| | - Marco Antonio Peliky Fontes
- a Department of Physiology and Biophysics , INCT, Institute of Biological Sciences, Federal University of Minas Gerais , Minas Gerais , Brazil
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Hall S, Deurveilher S, Ko KR, Burns J, Semba K. Region-specific increases in FosB/ΔFosB immunoreactivity in the rat brain in response to chronic sleep restriction. Behav Brain Res 2017; 322:9-17. [PMID: 28089853 DOI: 10.1016/j.bbr.2017.01.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/05/2017] [Accepted: 01/11/2017] [Indexed: 01/23/2023]
Abstract
Using a rat model of chronic sleep restriction (CSR) featuring periodic sleep deprivation with slowly rotating wheels (3h on/1h off), we previously observed that 99h of this protocol induced both homeostatic and allostatic (adaptive) changes in physiological and behavioural measures. Notably, the initial changes in sleep intensity and attention performance gradually adapted during CSR despite accumulating sleep loss. To identify brain regions involved in these responses, we used FosB/ΔFosB immunohistochemistry as a marker of chronic neuronal activation. Adult male rats were housed in motorized activity wheels and underwent the 3/1 CSR protocol for 99h, or 99h followed by 6 or 12days of recovery. Control rats were housed in home cages, locked activity wheels, or unlocked activity wheels that the animals could turn freely. Immunohistochemistry was conducted using an antibody that recognized both FosB and ΔFosB, and 24 brain regions involved in sleep/wake, autonomic, and limbic functions were examined. The number of darkly-stained FosB/ΔFosB-immunoreactive cells was increased immediately following 99h of CSR in 8/24 brain regions, including the medial preoptic and perifornical lateral hypothalamic areas, dorsomedial and paraventricular hypothalamic nuclei, and paraventricular thalamic nucleus. FosB/ΔFosB labeling was at control levels in all 8 brain areas following 6 or 12 recovery days, suggesting that most of the immunoreactivity immediately after CSR reflected FosB, the more transient marker of chronic neuronal activation. This region-specific induction of FosB/ΔFosB following CSR may be involved in the mechanisms underlying the allostatic changes in behavioural and physiological responses to CSR.
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Affiliation(s)
- Shannon Hall
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Samüel Deurveilher
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kristin Robin Ko
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Joan Burns
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kazue Semba
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Psychology & Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.
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33
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Chaar LJ, Coelho A, Silva NM, Festuccia WL, Antunes VR. High-fat diet-induced hypertension and autonomic imbalance are associated with an upregulation of CART in the dorsomedial hypothalamus of mice. Physiol Rep 2016; 4:4/11/e12811. [PMID: 27273815 PMCID: PMC4908489 DOI: 10.14814/phy2.12811] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/04/2016] [Indexed: 01/12/2023] Open
Abstract
We evaluated herein whether diet‐induced obesity alters sympathovagal balance, blood pressure, and neuropeptides levels at the hypothalamus and brainstem of mice. Male C57BL6J mice fed with a high‐fat (HFD) or a high‐fat high‐sucrose (HFHSu), or a regular chow diet (C) for 8 weeks were evaluated for metabolic parameters and blood pressure, the latter being performed in conscious freely moving mice. Spectral analysis from the records of systolic blood pressure (SBP) and cardiac pulse intervals (PI) was performed to analyse the autonomic balance in the cardiovascular system. HFD‐fed mice developed two distinct hemodynamic phenotypes: hypertensive mice (HFD‐H) with high systolic and diastolic BP levels and hypertension‐resistant mice (HFD‐R) whose BP levels were similar to C group. Spectral analysis of SBP and PI variabilities indicate that the low‐frequency (LF)/high‐frequency (HF) ratio, which is an index of sympathovagal balance, is higher in HFD‐H compared to HFD‐R. Along with hypertension and higher LF/HF ratio, HFD‐H mice presented increased hypothalamic mRNA levels of cocaine‐ and amphetamine‐regulated transcript (CART), and increased CART‐positive neurones in the dorsomedial hypothalamus (DMH) by high‐fat diet when compared to C group. Despite developing obesity to similar levels than HFD feeding, intake of a HFHSu was not associated with hypertension in mice neither CART levels increase. Collectively, our main findings indicate that high‐fat diet induced‐hypertension and autonomic imbalance are associated to an upregulation of CART levels in the DMH of mice.
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Affiliation(s)
- Laiali J Chaar
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Aline Coelho
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Natalia M Silva
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - William L Festuccia
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Vagner R Antunes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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Kobuch S, Fazalbhoy A, Brown R, Henderson LA, Macefield VG. Central circuitry responsible for the divergent sympathetic responses to tonic muscle pain in humans. Hum Brain Mapp 2016; 38:869-881. [PMID: 27696604 DOI: 10.1002/hbm.23424] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 12/18/2022] Open
Abstract
Experimentally induced tonic muscle pain evokes divergent muscle vasoconstrictor responses, with some individuals exhibiting a sustained increase in muscle sympathetic nerve activity (MSNA), and others a sustained decrease. These patterns cannot be predicted from an individual's baseline physiological or psychological measures. The aim of this study was to investigate whether the different muscle sympathetic responses to tonic muscle pain were associated with differential changes in regional brain activity. Functional magnetic resonance imaging (fMRI) of the brain was performed concurrently with microelectrode recording of MSNA from the peroneal nerve during a 40-min infusion of hypertonic saline into the ipsilateral tibialis anterior muscle. MSNA increased in 26 and decreased in 11 of 37 subjects during tonic muscle pain. Within the prefrontal and cingulate cortices, precuneus, nucleus accumbens, caudate nucleus, and dorsomedial hypothalamus, blood oxygen level dependent (BOLD) signal intensity increased in the increasing-MSNA group and remained at baseline or decreased in the decreasing-MSNA group. Similar responses occurred in the dorsolateral pons and in the region of the rostral ventrolateral medulla. By contrast, within the region of the dorsolateral periaqueductal gray (dlPAG) signal intensity initially increased in both groups but returned to baseline levels only in the increasing-MSNA group. These results suggest that the divergent sympathetic responses to muscle pain result from activation of a neural pathway that includes the dlPAG, an area thought to be responsible for the behavioral and cardiovascular responses to psychological rather than physical stressors. Hum Brain Mapp 38:869-881, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Sophie Kobuch
- School of Medicine, Western Sydney University, Sydney, Australia
| | - Azharuddin Fazalbhoy
- Neuroscience Research Australia, Sydney, Australia
- School of Health Sciences, RMIT University, Melbourne, VIC, Australia
| | - Rachael Brown
- School of Medicine, Western Sydney University, Sydney, Australia
- Neuroscience Research Australia, Sydney, Australia
| | - Luke A Henderson
- Discipline of Anatomy and Histology, University of Sydney, Sydney, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia
- Neuroscience Research Australia, Sydney, Australia
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Dynamic GABAergic afferent modulation of AgRP neurons. Nat Neurosci 2016; 19:1628-1635. [PMID: 27643429 PMCID: PMC5382799 DOI: 10.1038/nn.4392] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 08/22/2016] [Indexed: 02/07/2023]
Abstract
Agouti-related peptide (AgRP) neurons of the arcuate nucleus of the hypothalamus (ARC) promote homeostatic feeding at times of caloric insufficiency, yet they are rapidly suppressed by food-related sensory cues prior to ingestion. Here we identify a highly selective inhibitory afferent to AgRP neurons that serves as a neural determinant of this rapid modulation. Specifically, GABAergic projections arising from the ventral compartment of the dorsomedial nucleus of the hypothalamus (vDMH) contribute to the pre-consummatory modulation of ARCAgRP neurons. In a manner reciprocal to ARCAgRP neurons, ARC-projecting leptin receptor (LepR)-expressing GABAergic DMH neurons exhibit rapid activation upon availability of food that additionally reflects the relative value of the food. Thus, DMHLepR neurons form part of the sensory network that relays real-time information about the nature and availability of food to dynamically modulate ARCAgRP neuron activity and feeding behavior.
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Holwerda SW, Vianna LC, Restaino RM, Chaudhary K, Young CN, Fadel PJ. Arterial baroreflex control of sympathetic nerve activity and heart rate in patients with type 2 diabetes. Am J Physiol Heart Circ Physiol 2016; 311:H1170-H1179. [PMID: 27591221 DOI: 10.1152/ajpheart.00384.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/24/2016] [Indexed: 02/08/2023]
Abstract
Despite greater blood pressure reactivity to acute cardiovascular stressors and a higher prevalence of hypertension in type 2 diabetes (T2D) patients, limited information is available regarding arterial baroreflex (ABR) control in T2D. We hypothesized that ABR control of muscle sympathetic nerve activity (MSNA) and heart rate (HR) are attenuated in T2D patients. Seventeen T2D patients (50 ± 2 yr; 31 ± 1 kg/m2), 9 weight-matched controls (WM-CON, 46 ± 2 yr; 32 ± 2 kg/m2) and 10 lean controls (Lean-CON, 49 ± 3 yr; 23 ± 1 kg/m2), underwent bolus infusions of sodium nitroprusside (100 μg) followed 60 s later by phenylephrine (150 μg) and weighted linear regression performed. No group differences in overall sympathetic baroreflex gain were observed (T2D: -2.5 ± 0.3 vs. WM-CON: -2.6 ± 0.2 vs. Lean-CON: -2.7 ± 0.4 arbitrary units·beat·mmHg-1, P > 0.05) or in sympathetic baroreflex gain when derived separately during blood pressure (BP) falls (nitroprusside) and BP rises (phenylephrine). In contrast, overall cardiac baroreflex gain was reduced in T2D patients compared with Lean-CON (T2D: 8.2 ± 1.5 vs. Lean-CON: 15.6 ± 2.9 ms·mmHg-1, P < 0.05) and also tended to be reduced in WM-CON (9.3 ± 1.9 ms·mmHg-1) compared with Lean-CON (P = 0.059). Likewise, during BP rises, cardiac baroreflex gain was reduced in T2D patients and weight-matched controls compared with lean controls (P < 0.05), whereas no group differences were found during BP falls (P > 0.05). Sympathetic and cardiac ABR gains were comparable between normotensive and hypertensive T2D patients (P > 0.05). These findings suggest preserved ABR control of MSNA in T2D patients compared with both obese and lean age-matched counterparts, with a selective impairment in ABR HR control in T2D that may be related to obesity.
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Affiliation(s)
- Seth W Holwerda
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
| | - Lauro C Vianna
- Faculty of Physical Education, University of Brasilia, Distrito Federal, Brazil
| | - Robert M Restaino
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Kunal Chaudhary
- Department of Internal Medicine, University of Missouri, Columbia, Missouri
| | - Colin N Young
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia; and
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
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Brouillard C, Carrive P, Camus F, Bénoliel JJ, Similowski T, Sévoz-Couche C. Long-lasting bradypnea induced by repeated social defeat. Am J Physiol Regul Integr Comp Physiol 2016; 311:R352-64. [DOI: 10.1152/ajpregu.00021.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/18/2016] [Indexed: 12/17/2022]
Abstract
Repeated social defeat in the rat induces long-lasting cardiovascular changes associated with anxiety. In this study, we investigated the effects of repeated social defeat on breathing. Respiratory rate was extracted from the respiratory sinus arrhythmia (RSA) peak frequency of the ECG in rats subjected to social defeat for 4 consecutive days. Respiratory rate was recorded under anesthesia 6 days (D+10) or 26 days (D+30) after social defeat. At D+10, defeated (D) rats spent less time in the open arms of the elevated plus maze test, had heavier adrenal glands, and displayed bradypnea, unlike nondefeated animals. At D+30, all signs of anxiety had disappeared. However, one-half of the rats still displayed bradypnea (DL rats, for low respiratory rate indicated by a lower RSA frequency), whereas those with higher respiratory rate (DH rats) had recovered. Acute blockade of the dorsomedial hypothalamus (DMH) or nucleus tractus solitarii (NTS) 5-HT3 receptors reversed bradypnea in all D rats at D+10 and in DL rats at D+30. Respiratory rate was also recorded in conscious animals implanted with radiotelemetric ECG probes. DH rats recovered between D+10 and D+18, whereas DL rats remained bradypneic until D+30. In conclusion, social stress induces sustained chronic bradypnea mediated by DMH neurons and NTS 5-HT3 receptors. These changes are associated with an anxiety-like state that persists until D+10, followed by recovery. However, bradypnea may persist in one-half of the population up until D+30, despite apparent recovery of the anxiety-like state.
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Affiliation(s)
- Charly Brouillard
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France
- Sorbonne Universités, University Pierre and Marie Curie University Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
| | - Pascal Carrive
- Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Françoise Camus
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France
| | - Jean-Jacques Bénoliel
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France
| | - Thomas Similowski
- Sorbonne Universités, University Pierre and Marie Curie University Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
- Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Charles Foix, Service de Pneumologie et Réanimation Médicale, Paris, France; and
| | - Caroline Sévoz-Couche
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France
- Sorbonne Universités, University Pierre and Marie Curie University Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
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Sévoz-Couche C, Brouillard C. Key role of 5-HT 3 receptors in the nucleus tractus solitarii in cardiovagal stress reactivity. Neurosci Biobehav Rev 2016; 74:423-432. [PMID: 27131969 DOI: 10.1016/j.neubiorev.2016.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 04/18/2016] [Accepted: 04/20/2016] [Indexed: 01/01/2023]
Abstract
Serotonin plays a modulatory role in central control of the autonomic nervous system (ANS). The nucleus tractus solitarii (NTS) in the medulla is an area of viscerosomatic integration innervated by both central and peripheral serotonergic fibers. Influences from different origins therefore trigger the release of serotonin into the NTS and exert multiple influences on the ANS. This major influence on the ANS is also mediated by activation of several receptors in the NTS. In particular, the NTS is the central zone with the highest density of serotonin3 (5-HT3) receptors. In this review, we present evidence that 5-HT3 receptors in the NTS play a key role in one of the crucial homeostatic responses to acute and chronic stress: inhibitory modulation of the parasympathetic component of the ANS. The possible functional interactions of 5-HT3 receptors with GABAA and NK1 receptors in the NTS are also discussed.
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Affiliation(s)
- Caroline Sévoz-Couche
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France.
| | - Charly Brouillard
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
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Dai YWE, Lee YH, Chen JYS, Lin YK, Hwang LL. Expression of the M3 Muscarinic Receptor on Orexin Neurons that Project to the Rostral Ventrolateral Medulla. Anat Rec (Hoboken) 2016; 299:660-8. [PMID: 26910770 DOI: 10.1002/ar.23329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/10/2015] [Accepted: 12/22/2015] [Indexed: 11/11/2022]
Abstract
Activation of central cholinergic receptors causes a pressor response in rats, and the hypothalamus is important for this response. Projections from hypothalamic orexin neurons to the rostral ventrolateral medulla (RVLM) are involved in sympatho-excitation of the cardiovascular system. A small population of orexin neurons is regulated by cholinergic inputs through M3 muscarinic acetylcholine receptor (M3 R). To elucidate whether the M3 R on orexin neurons is involved in cardiosympathetic regulation through the RVLM, we examined the presence of the M3 R on retrograde-labeled RVLM-projecting orexin neurons. The retrograde tracer was unilaterally injected into the RVLM. Within the hypothalamus, retrograde-labeled neurons were located predominantly ipsilateral to the injection side. In the anterior hypothalamus (-1.5 to -2.3 mm to the bregma), retrograde-labeled neurons were densely distributed in the paraventricular nuclei and scattered in the retrochiasmatic area. At -2.3 to -3.5 mm from the bregma, labeled neurons were located in the regions where orexin neurons were situated, that is, the tuberal lateral hypothalamic area, perifornical area, and dorsomedial nuclei. Very few retrograde-labeled neurons were observed in the hypothalamus at -3.5 to -4.5 mm from the bregma. About 19.5% ± 1.6% of RVLM-projecting neurons in the tuberal hypothalamus were orexinergic. The M3 R was present on 18.7% ± 3.0% of RVLM-projecting orexin neurons. Injection of a muscarinic agonist, oxotremorine, in the perifornical area resulted in a pressor response, which was attenuated by a pretreatment of atropine. We conclude that cholinergic inputs to orexin neurons may be involved in cardiosympathetic regulation through the M3 R on the orexin neurons that directly project to the RVLM.
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Affiliation(s)
- Yu-Wen E Dai
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yen-Hsien Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jennifer Y S Chen
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Yen-Kuang Lin
- Biostatistic Center, Taipei Medical University, Taipei, Taiwan
| | - Ling-Ling Hwang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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40
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Major Autonomic Neuroregulatory Pathways Underlying Short- and Long-Term Control of Cardiovascular Function. Curr Hypertens Rep 2016; 18:18. [DOI: 10.1007/s11906-016-0625-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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41
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Dampney RAL. Central mechanisms regulating coordinated cardiovascular and respiratory function during stress and arousal. Am J Physiol Regul Integr Comp Physiol 2015; 309:R429-43. [DOI: 10.1152/ajpregu.00051.2015] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 05/28/2015] [Indexed: 02/07/2023]
Abstract
Actual or potentially threatening stimuli in the external environment (i.e., psychological stressors) trigger highly coordinated defensive behavioral responses that are accompanied by appropriate autonomic and respiratory changes. As discussed in this review, several brain regions and pathways have major roles in subserving the cardiovascular and respiratory responses to threatening stimuli, which may vary from relatively mild acute arousing stimuli to more prolonged life-threatening stimuli. One key region is the dorsomedial hypothalamus, which receives inputs from the cortex, amygdala, and other forebrain regions and which is critical for generating autonomic, respiratory, and neuroendocrine responses to psychological stressors. Recent studies suggest that the dorsomedial hypothalamus also receives an input from the dorsolateral column in the midbrain periaqueductal gray, which is another key region involved in the integration of stress-evoked cardiorespiratory responses. In addition, it has recently been shown that neurons in the midbrain colliculi can generate highly synchronized autonomic, respiratory, and somatomotor responses to visual, auditory, and somatosensory inputs. These collicular neurons may be part of a subcortical defense system that also includes the basal ganglia and which is well adapted to responding to threats that require an immediate stereotyped response that does not involve the cortex. The basal ganglia/colliculi system is phylogenetically ancient. In contrast, the defense system that includes the dorsomedial hypothalamus and cortex evolved at a later time, and appears to be better adapted to generating appropriate responses to more sustained threatening stimuli that involve cognitive appraisal.
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Affiliation(s)
- Roger A. L. Dampney
- School of Medical Sciences (Physiology) and Bosch Institute, University of Sydney, New South Wales, Australia
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42
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Silva F, Guidine PAM, Machado NL, Xavier CH, de Menezes R, Moraes-Santos T, Moraes MF, Chianca DA. The role of dorsomedial hypotalamus ionotropic glutamate receptors in the hypertensive and tachycardic responses evoked by Tityustoxin intracerebroventricular injection. Neurotoxicology 2015; 47:54-61. [DOI: 10.1016/j.neuro.2014.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 12/12/2014] [Accepted: 12/15/2014] [Indexed: 02/07/2023]
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Simonds S, Pryor J, Ravussin E, Greenway F, Dileone R, Allen A, Bassi J, Elmquist J, Keogh J, Henning E, Myers M, Licinio J, Brown R, Enriori P, O’Rahilly S, Sternson S, Grove K, Spanswick D, Farooqi I, Cowley M. Leptin mediates the increase in blood pressure associated with obesity. Cell 2014; 159:1404-16. [PMID: 25480301 PMCID: PMC4259491 DOI: 10.1016/j.cell.2014.10.058] [Citation(s) in RCA: 251] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 08/31/2014] [Accepted: 10/30/2014] [Indexed: 02/02/2023]
Abstract
Obesity is associated with increased blood pressure (BP), which in turn increases the risk of cardiovascular diseases. We found that the increase in leptin levels seen in diet-induced obesity (DIO) drives an increase in BP in rodents, an effect that was not seen in animals deficient in leptin or leptin receptors (LepR). Furthermore, humans with loss-of-function mutations in leptin and the LepR have low BP despite severe obesity. Leptin's effects on BP are mediated by neuronal circuits in the dorsomedial hypothalamus (DMH), as blocking leptin with a specific antibody, antagonist, or inhibition of the activity of LepR-expressing neurons in the DMH caused a rapid reduction of BP in DIO mice, independent of changes in weight. Re-expression of LepRs in the DMH of DIO LepR-deficient mice caused an increase in BP. These studies demonstrate that leptin couples changes in weight to changes in BP in mammalian species.
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Affiliation(s)
- Stephanie E. Simonds
- Department of Physiology, Monash Obesity and Diabetes Institute, Monash University, Clayton, VIC 3800, Australia
| | - Jack T. Pryor
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK,Neurosolutions Ltd., Coventry CV4 7ZS, UK
| | - Eric Ravussin
- The Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Frank L. Greenway
- The Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Ralph Dileone
- Department of Psychiatry, Yale School of Medicine, New Haven, CT 06511, USA
| | - Andrew M. Allen
- Department of Physiology, The University of Melbourne, Victoria 3010, Australia
| | - Jaspreet Bassi
- Department of Physiology, The University of Melbourne, Victoria 3010, Australia
| | - Joel K. Elmquist
- Division of Endocrinology & Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Julia M. Keogh
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Elana Henning
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Martin G. Myers
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Julio Licinio
- Mind and Brain Theme, South Australian Health and Medical Research Institute and Department of Psychiatry, School of Medicine, Flinders University, Adelaide, SA 5001, Australia
| | - Russell D. Brown
- Department of Physiology, Monash Obesity and Diabetes Institute, Monash University, Clayton, VIC 3800, Australia
| | - Pablo J. Enriori
- Department of Physiology, Monash Obesity and Diabetes Institute, Monash University, Clayton, VIC 3800, Australia
| | - Stephen O’Rahilly
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Scott M. Sternson
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Kevin L. Grove
- Division of Diabetes, Obesity & Metabolism, Oregon National Primate Research Center, Portland, OR 97239, USA
| | - David C. Spanswick
- Department of Physiology, Monash Obesity and Diabetes Institute, Monash University, Clayton, VIC 3800, Australia,Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - I. Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK,Corresponding author
| | - Michael A. Cowley
- Department of Physiology, Monash Obesity and Diabetes Institute, Monash University, Clayton, VIC 3800, Australia,Corresponding author
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Feetham CH, Barrett-Jolley R. NK1-receptor-expressing paraventricular nucleus neurones modulate daily variation in heart rate and stress-induced changes in heart rate variability. Physiol Rep 2014; 2:e12207. [PMID: 25472606 PMCID: PMC4332202 DOI: 10.14814/phy2.12207] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The paraventricular nucleus of the hypothalamus (PVN) is an established center of cardiovascular control, receiving projections from other nuclei of the hypothalamus such as the dorsomedial hypothalamus and the suprachiasmatic nucleus. The PVN contains a population of "pre-autonomic neurones" which project to the intermediolateralis of the spinal cord and increase sympathetic activity, blood pressure, and heart rate. These spinally projecting neurones express a number of membrane receptors including GABA and substance P NK1 receptors. Activation of NK1-expressing neurones increases heart rate, blood pressure, and sympathetic activity. However, their role in the pattern of overall cardiovascular control remains unknown. In this work, we use specific saporin lesion of NK1-expressing PVN rat neurones with SSP-SAP and telemetrically measure resting heart rate and heart rate variability (HRV) parameters in response to mild psychological stress. The HRV parameter "low frequency/high frequency ratio" is often used as an indicator of sympathetic activity and is significantly increased with psychological stress in control rats (0.84 ± 0.14 to 2.02 ± 0.15; P < 0.001; n = 3). We find the stress-induced increase in this parameter to be blunted in the SSP-SAP-lesioned rats (0.83 ± 0.09 to 0.93 ± 0.21; P > 0.05; n = 3). We also find a shift in daily variation of heart rate rhythm and conclude that NK1-expressing PVN neurones are involved with coupling of the cardiovascular system to daily heart rate variation and the sympathetic response to psychological stress.
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Affiliation(s)
- Claire H Feetham
- Institute of Ageing and Chronic Disease, Centre for Integrative Mammalian Biology, University of Liverpool, Liverpool, UK
| | - Richard Barrett-Jolley
- Institute of Ageing and Chronic Disease, Centre for Integrative Mammalian Biology, University of Liverpool, Liverpool, UK
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Xavier CH, Ianzer D, Lima AM, Marins FR, Pedrino GR, Vaz G, Menezes GB, Nalivaiko E, Fontes MAP. Excitatory amino acid receptors mediate asymmetry and lateralization in the descending cardiovascular pathways from the dorsomedial hypothalamus. PLoS One 2014; 9:e112412. [PMID: 25397884 PMCID: PMC4232378 DOI: 10.1371/journal.pone.0112412] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 10/14/2014] [Indexed: 02/05/2023] Open
Abstract
The dorsomedial hypothalamus (DMH) and lateral/dorsolateral periaqueductal gray (PAG) are anatomically and functionally connected. Both the DMH and PAG depend on glutamatergic inputs for activation. We recently reported that removal of GABA-ergic tone in the unilateral DMH produces: asymmetry, that is, a right- (R-) sided predominance in cardiac chronotropism, and lateralization, that is, a greater increase in ipsilateral renal sympathetic activity (RSNA). In the current study, we investigated whether excitatory amino acid (EAA) receptors in the DMH-PAG pathway contribute to the functional interhemispheric difference. In urethane (1.2 to 1.4 g/kg, i.p.) anesthetized rats, we observed that: (i) nanoinjections of N-methyl D-aspartate (NMDA 100 pmol/100 nl) into the unilateral DMH produced the same right-sided predominance in the control of cardiac chronotropy, (ii) nanoinjections of NMDA into the ipsilateral DMH or PAG evoked lateralized RSNA responses, and (iii) blockade of EAA receptors in the unilateral DMH attenuated the cardiovascular responses evoked by injection of NMDA into either the R- or left- (L-) PAG. In awake rats, nanoinjection of kynurenic acid (1 nmol/100 nL) into the L-DMH or R- or L-PAG attenuated the tachycardia evoked by air stress. However, the magnitude of stress-evoked tachycardia was smallest when the EAA receptors of the R-DMH were blocked. We conclude that EAA receptors contribute to the right-sided predominance in cardiac chronotropism. This interhemispheric difference that involves EAA receptors was observed in the DMH but not in the PAG.
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Affiliation(s)
- Carlos Henrique Xavier
- Laboratório de Fisiologia e Terapêutica Cardiovascular, Departamento Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
- * E-mail:
| | - Danielle Ianzer
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Augusto Martins Lima
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Fernanda Ribeiro Marins
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gustavo Rodrigues Pedrino
- Laboratório de Fisiologia e Terapêutica Cardiovascular, Departamento Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Gisele Vaz
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gustavo Batista Menezes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Eugene Nalivaiko
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia
| | - Marco Antônio Peliky Fontes
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
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46
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Cardiovascular and behavioral effects produced by administration of liposome-entrapped GABA into the rat central nervous system. Neuroscience 2014; 285:60-9. [PMID: 25446344 DOI: 10.1016/j.neuroscience.2014.10.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 10/08/2014] [Accepted: 10/29/2014] [Indexed: 01/03/2023]
Abstract
Liposomes are nanosystems that allow a sustained release of entrapped substances. Gamma-aminobutyric acid (GABA) is the most prevalent inhibitory neurotransmitter of the central nervous system (CNS). We developed a liposomal formulation of GABA for application in long-term CNS functional studies. Two days after liposome-entrapped GABA was injected intracerebroventricularly (ICV), Wistar rats were submitted to the following evaluations: (1) changes in mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) to ICV injection of bicuculline methiodide (BMI) in anesthetized rats; (2) changes in cardiovascular reactivity to air jet stress in conscious rats; and (3) anxiety-like behavior in conscious rats. GABA and saline-containing pegylated liposomes were prepared with a mean diameter of 200 nm. Rats with implanted cannulas targeted to lateral cerebral ventricle (n = 5-8/group) received either GABA solution (GS), empty liposomes (EL) or GABA-containing liposomes (GL). Following (48 h) central microinjection (2 μL, 0.09 M and 99 g/L) of liposomes, animals were submitted to the different protocols. Animals that received GL demonstrated attenuated response of RSNA to BMI microinjection (GS 48 ± 9, EL 43 ± 9, GL 11 ± 8%; P < 0.05), blunted tachycardia in the stress trial (ΔHR: GS 115 ± 14, EL 117 ± 10, GL 74 ± 9 bpm; P<0.05) and spent more time in the open arms of elevated plus maze (EL 6 ± 2 vs. GL 18 ± 5%; P = 0.028) compared with GS and EL groups. These results indicate that liposome-entrapped GABA can be a potential tool for exploring the chronic effects of GABA in specific regions and pathways of the central nervous system.
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47
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Emotional stress and sympathetic activity: Contribution of dorsomedial hypothalamus to cardiac arrhythmias. Brain Res 2014; 1554:49-58. [DOI: 10.1016/j.brainres.2014.01.043] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 01/23/2014] [Accepted: 01/24/2014] [Indexed: 02/07/2023]
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48
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Molkov YI, Zaretskaia MV, Zaretsky DV. Meth math: modeling temperature responses to methamphetamine. Am J Physiol Regul Integr Comp Physiol 2014; 306:R552-66. [PMID: 24500434 DOI: 10.1152/ajpregu.00365.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Methamphetamine (Meth) can evoke extreme hyperthermia, which correlates with neurotoxicity and death in laboratory animals and humans. The objective of this study was to uncover the mechanisms of a complex dose dependence of temperature responses to Meth by mathematical modeling of the neuronal circuitry. On the basis of previous studies, we composed an artificial neural network with the core comprising three sequentially connected nodes: excitatory, medullary, and sympathetic preganglionic neuronal (SPN). Meth directly stimulated the excitatory node, an inhibitory drive targeted the medullary node, and, in high doses, an additional excitatory drive affected the SPN node. All model parameters (weights of connections, sensitivities, and time constants) were subject to fitting experimental time series of temperature responses to 1, 3, 5, and 10 mg/kg Meth. Modeling suggested that the temperature response to the lowest dose of Meth, which caused an immediate and short hyperthermia, involves neuronal excitation at a supramedullary level. The delay in response after the intermediate doses of Meth is a result of neuronal inhibition at the medullary level. Finally, the rapid and robust increase in body temperature induced by the highest dose of Meth involves activation of high-dose excitatory drive. The impairment in the inhibitory mechanism can provoke a life-threatening temperature rise and makes it a plausible cause of fatal hyperthermia in Meth users. We expect that studying putative neuronal sites of Meth action and the neuromediators involved in a detailed model of this system may lead to more effective strategies for prevention and treatment of hyperthermia induced by amphetamine-like stimulants.
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Affiliation(s)
- Yaroslav I Molkov
- Department of Mathematical Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana; and
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49
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Abreu AR, de Abreu AR, Santos LT, de Souza AA, da Silva LG, Chianca DA, de Menezes RC. Blunted GABA-mediated inhibition within the dorsomedial hypothalamus potentiates the cardiovascular response to emotional stress in rats fed a high-fat diet. Neuroscience 2014; 262:21-30. [PMID: 24397951 DOI: 10.1016/j.neuroscience.2013.12.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/23/2013] [Accepted: 12/24/2013] [Indexed: 11/25/2022]
Abstract
Rats fed a high-fat diet (HFD) present an exaggerated endocrine response to stress conditions, which, like obesity, show a high correlation with cardiovascular diseases. Meanwhile the GABAergic neurotransmission within the dorsomedial hypothalamus (DMH) is involved in the regulation of the physiological responses during emotional stress. Here we evaluated the influence of obesity, induced by a HFD, on the cardiovascular responses induced by air jet stress in rats, and the role of the GABAergic tonus within the DMH in these changes. Our results showed that consumption of a HFD (45% w/w fat) for 9 weeks induced obesity and increases in baseline mean arterial pressure (MAP) and heart rate (HR). Moreover, obesity potentiated stress responsiveness, evidenced by the greater changes in MAP and HR induced by stress in obese rats. The injection of muscimol into the DMH reduced the maximal increases in HR and MAP induced by stress in both groups; however, the reduction in the maximal increases in MAP in the HFD group was less pronounced. Moreover, the injection of muscimol into the DMH of obese rats was less effective in reducing the stress-induced tachycardia, since the HR attained the same levels at the end of the stress paradigm as after the vehicle injection. Injection of bicuculline into DMH induced increases in MAP and HR in both groups. Nevertheless, obesity shortened the tachycardic response to bicuculline injection. These data show that obesity potentiates the cardiovascular response to stress in rats due to an inefficient GABAA-mediated inhibition within the DMH.
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Affiliation(s)
- A R Abreu
- Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, MG, Brazil.
| | - A R de Abreu
- Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, MG, Brazil.
| | - L T Santos
- Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, MG, Brazil.
| | - A A de Souza
- Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, MG, Brazil.
| | - L G da Silva
- Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, MG, Brazil.
| | - D A Chianca
- Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, MG, Brazil.
| | - R C de Menezes
- Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, MG, Brazil.
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50
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Moraes DJA, Machado BH, Zoccal DB. Coupling of respiratory and sympathetic activities in rats submitted to chronic intermittent hypoxia. PROGRESS IN BRAIN RESEARCH 2014; 212:25-38. [PMID: 25194191 DOI: 10.1016/b978-0-444-63488-7.00002-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The respiratory modulation of sympathetic activity relies on the balance between excitatory and inhibitory inputs from the brainstem respiratory network to presympathetic neurons of the rostral ventrolateral medulla. This central respiratory-sympathetic contributes for the generation of respiratory-related rhythmical oscillations in heart rate and arterial pressure levels, whose functional effects on the blood gas exchange/perfusion and cardiac work remain to be elucidated. Herein, we discuss the experimental evidence describing the potential neural mechanisms underlying the entrainment between respiratory and sympathetic activities at baseline conditions as well as under conditions of metabolic challenges. We also discuss the possible implications of changes in the strength or pattern of the central respiratory-sympathetic coupling in the genesis of sympathetic overactivity and neurogenic hypertension, including that associated with the exposure to chronic intermittent hypoxia.
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Affiliation(s)
- Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, Dentistry School of Araraquara, São Paulo State University, Araraquara, São Paulo, Brazil.
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