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de Souza JGV, de Souza DP, da Silva CAA, Martins Sá RW, Paton JFR, da Silva MP, Moraes DJA. Electrophysiological Properties and Morphology of Cardiac and Pulmonary Motoneurons within the Dorsal Motor Nucleus of the Vagus of Rats. Neuroscience 2024; 551:153-165. [PMID: 38821242 DOI: 10.1016/j.neuroscience.2024.05.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/02/2024]
Abstract
The dorsal motor nucleus of the vagus (DMV) contains parasympathetic motoneurons that project to the heart and lungs. These motoneurons control ventricular excitability/contractility and airways secretions/blood flow, respectively. However, their electrophysiological properties, morphology and synaptic input activity remain unknown. One important ionic current described in DMV motoneurons controlling their electrophysiological behaviour is the A-type mediated by voltage-dependent K+ (Kv) channels. Thus, we compared the electrophysiological properties, synaptic activity, morphology, A-type current density, and single cell expression of Kv subunits, that contribute to macroscopic A-type currents, between DMV motoneurons projecting to either the heart or lungs of adult male rats. Using retrograde labelling, we visualized distinct DMV motoneurons projecting to the heart or lungs in acutely prepared medullary slices. Subsequently, whole cell recordings, morphological reconstruction and single motoneuron qRT-PCR studies were performed. DMV pulmonary motoneurons were more depolarized, electrically excitable, presented higher membrane resistance, broader action potentials and received greater excitatory synaptic inputs compared to cardiac DMV motoneurons. These differences were in part due to highly branched dendritic complexity and lower magnitude of A-type K+ currents. By evaluating expression of channels that mediate A-type currents from single motoneurons, we demonstrated a lower level of Kv4.2 in pulmonary versus cardiac motoneurons, whereas Kv4.3 and Kv1.4 levels were similar. Thus, with the distinct electrical, morphological, and molecular properties of DMV cardiac and pulmonary motoneurons, we surmise that these cells offer a new vista of opportunities for genetic manipulation providing improvement of parasympathetic function in cardiorespiratory diseases such heart failure and asthma.
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Affiliation(s)
- Júlia G V de Souza
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Daniel P de Souza
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Carlos A A da Silva
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Renato W Martins Sá
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Julian F R Paton
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Melina P da Silva
- Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil.
| | - Davi J A Moraes
- Department of Physiology and Biophysics, Biomedical Science Institute, University of São Paulo, São Paulo, SP, Brazil.
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2
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Strain MM, Conley NJ, Kauffman LS, Espinoza L, Fedorchak S, Martinez PC, Crook ME, Jalil M, Hodes GE, Abbott SB, Güler AD, Campbell JN, Boychuk CR. Dorsal motor vagal neurons can elicit bradycardia and reduce anxiety-like behavior. iScience 2024; 27:109137. [PMID: 38420585 PMCID: PMC10901094 DOI: 10.1016/j.isci.2024.109137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/16/2023] [Accepted: 02/01/2024] [Indexed: 03/02/2024] Open
Abstract
Cardiovagal neurons (CVNs) innervate cardiac ganglia through the vagus nerve to control cardiac function. Although the cardioinhibitory role of CVNs in nucleus ambiguus (CVNNA) is well established, the nature and functionality of CVNs in dorsal motor nucleus of the vagus (CVNDMV) is less clear. We therefore aimed to characterize CVNDMV anatomically, physiologically, and functionally. Optogenetically activating cholinergic DMV neurons resulted in robust bradycardia through peripheral muscarinic (parasympathetic) and nicotinic (ganglionic) acetylcholine receptors, but not beta-1-adrenergic (sympathetic) receptors. Retrograde tracing from the cardiac fat pad labeled CVNNA and CVNDMV through the vagus nerve. Using whole-cell patch-clamp, CVNDMV demonstrated greater hyperexcitability and spontaneous action potential firing ex vivo despite similar resting membrane potentials, compared to CVNNA. Chemogenetically activating DMV also caused significant bradycardia with a correlated reduction in anxiety-like behavior. Thus, DMV contains uniquely hyperexcitable CVNs and is capable of cardioinhibition and robust anxiolysis.
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Affiliation(s)
- Misty M. Strain
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | | | - Lily S. Kauffman
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Stephanie Fedorchak
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | | | - Maisie E. Crook
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Maira Jalil
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Georgia E. Hodes
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Stephen B.G. Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Ali D. Güler
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Carie R. Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
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3
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Coverdell TC, Abbott SBG, Campbell JN. Molecular cell types as functional units of the efferent vagus nerve. Semin Cell Dev Biol 2024; 156:210-218. [PMID: 37507330 PMCID: PMC10811285 DOI: 10.1016/j.semcdb.2023.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023]
Abstract
The vagus nerve vitally connects the brain and body to coordinate digestive, cardiorespiratory, and immune functions. Its efferent neurons, which project their axons from the brainstem to the viscera, are thought to comprise "functional units" - neuron populations dedicated to the control of specific vagal reflexes or organ functions. Previous research indicates that these functional units differ from one another anatomically, neurochemically, and physiologically but have yet to define their identity in an experimentally tractable way. However, recent work with genetic technology and single-cell genomics suggests that genetically distinct subtypes of neurons may be the functional units of the efferent vagus. Here we review how these approaches are revealing the organizational principles of the efferent vagus in unprecedented detail.
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Affiliation(s)
- Tatiana C Coverdell
- Biomedical Sciences Graduate Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22903, USA
| | - John N Campbell
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA.
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4
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Jalil M, Coverdell TC, Gutierrez VA, Crook ME, Shi J, Stornetta DS, Schwalbe DC, Abbott SBG, Campbell JN. Molecular Disambiguation of Heart Rate Control by the Nucleus Ambiguus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.16.571991. [PMID: 38168262 PMCID: PMC10760142 DOI: 10.1101/2023.12.16.571991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The nucleus ambiguus (nAmb) provides parasympathetic control of cardiorespiratory functions as well as motor control of the upper airways and striated esophagus. A subset of nAmb neurons innervates the heart through the vagus nerve to control cardiac function at rest and during key autonomic reflexes such as the mammalian diving reflex. These cardiovagal nAmb neurons may be molecularly and anatomically distinct, but how they differ from other nAmb neurons in the adult brain remains unclear. We therefore classified adult mouse nAmb neurons based on their genome-wide expression profiles, innervation of cardiac ganglia, and ability to control HR. Our integrated analysis of single-nucleus RNA-sequencing data predicted multiple molecular subtypes of nAmb neurons. Mapping the axon projections of one nAmb neuron subtype, Npy2r-expressing nAmb neurons, showed that they innervate cardiac ganglia. Optogenetically stimulating all nAmb vagal efferent neurons dramatically slowed HR to a similar extent as selectively stimulating Npy2r+ nAmb neurons, but not other subtypes of nAmb neurons. Finally, we trained mice to perform voluntary underwater diving, which we use to show Npy2r+ nAmb neurons are activated by the diving response, consistent with a cardiovagal function for this nAmb subtype. These results together reveal the molecular organization of nAmb neurons and its control of heart rate.
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Affiliation(s)
- Maira Jalil
- Department of Biology, University of Virginia, Charlottesville, VA
| | | | | | - Maisie E. Crook
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Jiachen Shi
- Department of Biology, University of Virginia, Charlottesville, VA
| | | | - Dana C. Schwalbe
- Department of Biology, University of Virginia, Charlottesville, VA
| | | | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, VA
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5
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Strain MM, Conley NJ, Kauffman LS, Espinoza L, Fedorchak S, Martinez PC, Crook ME, Jalil M, Hodes GE, Abbott SBG, Güler AD, Campbell JN, Boychuk CR. Dorsal Motor Vagal Neurons Can Elicit Bradycardia and Reduce Anxiety-Like Behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.566855. [PMID: 38014247 PMCID: PMC10680764 DOI: 10.1101/2023.11.14.566855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Cardiovagal neurons (CVNs) innervate cardiac ganglia through the vagus nerve to control cardiac function. Although the cardioinhibitory role of CVNs in nucleus ambiguus (CVNNA) is well established, the nature and functionality of CVNs in dorsal motor nucleus of the vagus (CVNDMV) is less clear. We therefore aimed to characterize CVNDMV anatomically, physiologically, and functionally. Optogenetically activating cholinergic DMV neurons resulted in robust bradycardia through peripheral muscarinic (parasympathetic) and nicotinic (ganglionic) acetylcholine receptors, but not beta-1-adrenergic (sympathetic) receptors. Retrograde tracing from the cardiac fat pad labeled CVNNA and CVNDMV through the vagus nerve. Using whole cell patch clamp, CVNDMV demonstrated greater hyperexcitability and spontaneous action potential firing ex vivo despite similar resting membrane potentials, compared to CVNNA. Chemogenetically activating DMV also caused significant bradycardia with a correlated reduction in anxiety-like behavior. Thus, DMV contains uniquely hyperexcitable CVNs capable of cardioinhibition and robust anxiolysis.
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Affiliation(s)
- Misty M. Strain
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | | | - Lily S. Kauffman
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | - Stephanie Fedorchak
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | | | - Maisie E. Crook
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Maira Jalil
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Georgia E. Hodes
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | | | - Ali D. Güler
- Department of Biology, University of Virginia, Charlottesville, VA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Carie R. Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO
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6
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van Weperen VYH, Vaseghi M. Cardiac vagal afferent neurotransmission in health and disease: review and knowledge gaps. Front Neurosci 2023; 17:1192188. [PMID: 37351426 PMCID: PMC10282187 DOI: 10.3389/fnins.2023.1192188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/23/2023] [Indexed: 06/24/2023] Open
Abstract
The meticulous control of cardiac sympathetic and parasympathetic tone regulates all facets of cardiac function. This precise calibration of cardiac efferent innervation is dependent on sensory information that is relayed from the heart to the central nervous system. The vagus nerve, which contains vagal cardiac afferent fibers, carries sensory information to the brainstem. Vagal afferent signaling has been predominantly shown to increase parasympathetic efferent response and vagal tone. However, cardiac vagal afferent signaling appears to change after cardiac injury, though much remains unknown. Even though subsequent cardiac autonomic imbalance is characterized by sympathoexcitation and parasympathetic dysfunction, it remains unclear if, and to what extent, vagal afferent dysfunction is involved in the development of vagal withdrawal. This review aims to summarize the current understanding of cardiac vagal afferent signaling under in health and in the setting of cardiovascular disease, especially after myocardial infarction, and to highlight the knowledge gaps that remain to be addressed.
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Affiliation(s)
- Valerie Y. H. van Weperen
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States
| | - Marmar Vaseghi
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrhythmia Center, Los Angeles, CA, United States
- Molecular, Cellular, and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States
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7
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Strain MM, Espinoza L, Fedorchak S, Littlejohn EL, Andrade MA, Toney GM, Boychuk CR. Early central cardiovagal dysfunction after high fat diet in a murine model. Sci Rep 2023; 13:6550. [PMID: 37085567 PMCID: PMC10121716 DOI: 10.1038/s41598-023-32492-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/28/2023] [Indexed: 04/23/2023] Open
Abstract
High fat diet (HFD) promotes cardiovascular disease and blunted cardiac vagal regulation. Temporal onset of loss of cardiac vagal control and its underlying mechanism are presently unclear. We tested our hypothesis that reduced central vagal regulation occurs early after HFD and contributes to poor cardiac regulation using cardiovascular testing paired with pharmacology in mice, molecular biology, and a novel bi-transgenic mouse line. Results show HFD, compared to normal fat diet (NFD), significantly blunted cardio/pulmonary chemoreflex bradycardic responses after 15 days, extending as far as tested (> 30 days). HFD produced resting tachycardia by day 3, reflected significant loss of parasympathetic tone. No differences in bradycardic responses to graded electrical stimulation of the distal cut end of the cervical vagus indicated diet-induced differences in vagal activity were centrally mediated. In nucleus ambiguus (NA), surface expression of δ-subunit containing type A gamma-aminobutyric acid receptors (GABAA(δ)R) increased at day 15 of HFD. Novel mice lacking δ-subunit expression in vagal motor neurons (ChAT-δnull) failed to exhibit blunted reflex bradycardia or resting tachycardia after two weeks of HFD. Thus, reduced parasympathetic output contributes to early HFD-induced HR dysregulation, likely through increased GABAA(δ)Rs. Results underscore need for research on mechanisms of early onset increases in GABAA(δ)R expression and parasympathetic dysfunction after HFD.
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Affiliation(s)
- Misty M Strain
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, 7703 Floyd Curl Drive, Mail Code 7746, San Antonio, TX, 78229-3901, USA
| | - Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, 7703 Floyd Curl Drive, Mail Code 7746, San Antonio, TX, 78229-3901, USA
| | - Stephanie Fedorchak
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, 7703 Floyd Curl Drive, Mail Code 7746, San Antonio, TX, 78229-3901, USA
| | - Erica L Littlejohn
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, 7703 Floyd Curl Drive, Mail Code 7746, San Antonio, TX, 78229-3901, USA
| | - Mary Ann Andrade
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, 7703 Floyd Curl Drive, Mail Code 7746, San Antonio, TX, 78229-3901, USA
| | - Glenn M Toney
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, 7703 Floyd Curl Drive, Mail Code 7746, San Antonio, TX, 78229-3901, USA
| | - Carie R Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, 7703 Floyd Curl Drive, Mail Code 7746, San Antonio, TX, 78229-3901, USA.
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8
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Arai T, Kanazawa H, Kimura K, Munakata M, Yamakawa H, Shinmura K, Yuasa S, Sano M, Fukuda K. Upregulation of neuropeptide Y in cardiac sympathetic nerves induces stress (Takotsubo) cardiomyopathy. Front Neurosci 2022; 16:1013712. [DOI: 10.3389/fnins.2022.1013712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Substantial emotional or physical stress may lead to an imbalance in the brain, resulting in stress cardiomyopathy (SC) and transient left ventricular (LV) apical ballooning. Even though these conditions are severe, their precise underlying mechanisms remain unclear. Appropriate animal models are needed to elucidate the precise mechanisms. In this study, we established a new animal model of epilepsy-induced SC. The SC model showed an increased expression of the acute phase reaction protein, c-Fos, in the paraventricular hypothalamic nucleus (PVN), which is the sympathetic nerve center of the brain. Furthermore, we observed a significant upregulation of neuropeptide Y (NPY) expression in the left stellate ganglion (SG) and cardiac sympathetic nerves. NPY showed neither positive nor negative inotropic and chronotropic effects. On the contrary, NPY could interrupt β-adrenergic signaling in cardiomyocytes when exposure to NPY precedes exposure to noradrenaline. Moreover, its elimination in the left SG via siRNA treatment tended to reduce the incidence of SC. Thus, our results indicated that upstream sympathetic activation induced significant upregulation of NPY in the left SG and cardiac sympathetic nerves, resulting in cardiac dysfunctions like SC.
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9
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Neuhuber WL, Berthoud HR. Functional anatomy of the vagus system: How does the polyvagal theory comply? Biol Psychol 2022; 174:108425. [PMID: 36100134 DOI: 10.1016/j.biopsycho.2022.108425] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022]
Abstract
Due to its pivotal role in autonomic networks and interoception, the vagus attracts continued interest from both basic scientists and therapists of various clinical disciplines. In particular, the widespread use of heart rate variability as an index of autonomic cardiac control and a proposed central role of the vagus in biopsychological concepts, e.g., the polyvagal theory, provide a good opportunity to recall basic features of vagal anatomy. In addition to the "classical" vagal brainstem nuclei, i.e., dorsal motor nucleus, nucleus ambiguus and nucleus tractus solitarii, the spinal trigeminal and paratrigeminal nuclei come into play as targets of vagal afferents. On the other hand, the nucleus of the solitary tract receives and integrates not only visceral but also somatic afferents.
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Affiliation(s)
- Winfried L Neuhuber
- Institute of Anatomy and Cell Biology, Friedrich-Alexander-Universität, Krankenhausstrasse 9, Erlangen, Germany.
| | - Hans-Rudolf Berthoud
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
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10
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Abstract
Much of biology is rhythmical and comprises oscillators that can couple. These have optimized energy efficiency and have been preserved during evolution. The respiratory and cardiovascular systems contain numerous oscillators, and importantly, they couple. This coupling is dynamic but essential for an efficient transmission of neural information critical for the precise linking of breathing and oxygen delivery while permitting adaptive responses to changes in state. The respiratory pattern generator and the neural network responsible for sympathetic and cardiovagal (parasympathetic) tone generation interact at many levels ensuring that cardiac output and regional blood flow match oxygen delivery to the lungs and tissues efficiently. The most classic manifestations of these interactions are respiratory sinus arrhythmia and the respiratory modulation of sympathetic nerve activity. These interactions derive from shared somatic and cardiopulmonary afferent inputs, reciprocal interactions between brainstem networks and inputs from supra-pontine regions. Disrupted respiratory-cardiovascular coupling can result in disease, where it may further the pathophysiological sequelae and be a harbinger of poor outcomes. This has been well documented by diminished respiratory sinus arrhythmia and altered respiratory sympathetic coupling in animal models and/or patients with myocardial infarction, heart failure, diabetes mellitus, and neurological disorders as stroke, brain trauma, Parkinson disease, or epilepsy. Future research needs to assess the therapeutic potential for ameliorating respiratory-cardiovascular coupling in disease.
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Affiliation(s)
- James P Fisher
- Manaaki Manawa-The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, Auckland, New Zealand
| | - Tymoteusz Zera
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Julian F R Paton
- Manaaki Manawa-The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, Auckland, New Zealand.
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11
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Angiotensin II and the Cardiac Parasympathetic Nervous System in Hypertension. Int J Mol Sci 2021; 22:ijms222212305. [PMID: 34830184 PMCID: PMC8624735 DOI: 10.3390/ijms222212305] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 01/08/2023] Open
Abstract
The renin-angiotensin-aldosterone system (RAAS) impacts cardiovascular homeostasis via direct actions on peripheral blood vessels and via modulation of the autonomic nervous system. To date, research has primarily focused on the actions of the RAAS on the sympathetic nervous system. Here, we review the critical role of the RAAS on parasympathetic nerve function during normal physiology and its role in cardiovascular disease, focusing on hypertension. Angiotensin (Ang) II receptors are present throughout the parasympathetic nerves and can modulate vagal activity via actions at the level of the nerve endings as well as via the circumventricular organs and as a neuromodulator acting within brain regions. There is tonic inhibition of cardiac vagal tone by endogenous Ang II. We review the actions of Ang II via peripheral nerve endings as well as via central actions on brain regions. We review the evidence that Ang II modulates arterial baroreflex function and examine the pathways via which Ang II can modulate baroreflex control of cardiac vagal drive. Although there is evidence that Ang II can modulate parasympathetic activity and has the potential to contribute to impaired baseline levels and impaired baroreflex control during hypertension, the exact central regions where Ang II acts need further investigation. The beneficial actions of angiotensin receptor blockers in hypertension may be mediated in part via actions on the parasympathetic nervous system. We highlight important unknown questions about the interaction between the RAAS and the parasympathetic nervous system and conclude that this remains an important area where future research is needed.
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12
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Espinoza L, Fedorchak S, Boychuk CR. Interplay Between Systemic Metabolic Cues and Autonomic Output: Connecting Cardiometabolic Function and Parasympathetic Circuits. Front Physiol 2021; 12:624595. [PMID: 33776789 PMCID: PMC7991741 DOI: 10.3389/fphys.2021.624595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 02/12/2021] [Indexed: 12/21/2022] Open
Abstract
There is consensus that the heart is innervated by both the parasympathetic and sympathetic nervous system. However, the role of the parasympathetic nervous system in controlling cardiac function has received significantly less attention than the sympathetic nervous system. New neuromodulatory strategies have renewed interest in the potential of parasympathetic (or vagal) motor output to treat cardiovascular disease and poor cardiac function. This renewed interest emphasizes a critical need to better understand how vagal motor output is generated and regulated. With clear clinical links between cardiovascular and metabolic diseases, addressing this gap in knowledge is undeniably critical to our understanding of the interaction between metabolic cues and vagal motor output, notwithstanding the classical role of the parasympathetic nervous system in regulating gastrointestinal function and energy homeostasis. For this reason, this review focuses on the central, vagal circuits involved in sensing metabolic state(s) and enacting vagal motor output to influence cardiac function. It will review our current understanding of brainstem vagal circuits and their unique position to integrate metabolic signaling into cardiac activity. This will include an overview of not only how metabolic cues alter vagal brainstem circuits, but also how vagal motor output might influence overall systemic concentrations of metabolic cues known to act on the cardiac tissue. Overall, this review proposes that the vagal brainstem circuits provide an integrative network capable of regulating and responding to metabolic cues to control cardiac function.
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Affiliation(s)
- Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Stephanie Fedorchak
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Carie R Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
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13
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Input-output signal processing plasticity of vagal motor neurons in response to cardiac ischemic injury. iScience 2021; 24:102143. [PMID: 33665562 PMCID: PMC7898179 DOI: 10.1016/j.isci.2021.102143] [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: 11/17/2020] [Revised: 01/01/2021] [Accepted: 01/29/2021] [Indexed: 11/23/2022] Open
Abstract
Vagal stimulation is emerging as the next frontier in bioelectronic medicine to modulate peripheral organ health and treat disease. The neuronal molecular phenotypes in the dorsal motor nucleus of the vagus (DMV) remain largely unexplored, limiting the potential for harnessing the DMV plasticity for therapeutic interventions. We developed a mesoscale single-cell transcriptomics data from hundreds of DMV neurons under homeostasis and following physiological perturbations. Our results revealed that homeostatic DMV neuronal states can be organized into distinguishable input-output signal processing units. Remote ischemic preconditioning induced a distinctive shift in the neuronal states toward diminishing the role of inhibitory inputs, with concomitant changes in regulatory microRNAs miR-218a and miR-495. Chronic cardiac ischemic injury resulted in a dramatic shift in DMV neuronal states suggestive of enhanced neurosecretory function. We propose a DMV molecular network mechanism that integrates combinatorial neurotransmitter inputs from multiple brain regions and humoral signals to modulate cardiac health.
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14
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Hadaya J, Ardell JL. Autonomic Modulation for Cardiovascular Disease. Front Physiol 2020; 11:617459. [PMID: 33414727 PMCID: PMC7783451 DOI: 10.3389/fphys.2020.617459] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022] Open
Abstract
Dysfunction of the autonomic nervous system has been implicated in the pathogenesis of cardiovascular disease, including congestive heart failure and cardiac arrhythmias. Despite advances in the medical and surgical management of these entities, progression of disease persists as does the risk for sudden cardiac death. With improved knowledge of the dynamic relationships between the nervous system and heart, neuromodulatory techniques such as cardiac sympathetic denervation and vagal nerve stimulation (VNS) have emerged as possible therapeutic approaches for the management of these disorders. In this review, we present the structure and function of the cardiac nervous system and the remodeling that occurs in disease states, emphasizing the concept of increased sympathoexcitation and reduced parasympathetic tone. We review preclinical evidence for vagal nerve stimulation, and early results of clinical trials in the setting of congestive heart failure. Vagal nerve stimulation, and other neuromodulatory techniques, may improve the management of cardiovascular disorders, and warrant further study.
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Affiliation(s)
- Joseph Hadaya
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, United States.,UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA, United States.,Molecular, Cellular, and Integrative Physiology Program, UCLA, Los Angeles, CA, United States
| | - Jeffrey L Ardell
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, United States.,UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA, United States
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15
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Hanna P, L Ardell J, ShivkumarKalyanam K. Cardiac Neuroanatomy for the Cardiac Electrophysiologist. J Atr Fibrillation 2020; 13:2407. [PMID: 33024507 DOI: 10.4022/jafib.2407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/11/2019] [Accepted: 10/12/2019] [Indexed: 12/22/2022]
Abstract
The cardiac neuraxis is integral to cardiac physiology, and its dysregulation is implicated in cardiovascular disease. Neuromodulatory therapies are being developed that target the cardiac autonomic nervous system (ANS) to treat cardiac pathophysiology. An appreciation of the cardiac neuroanatomy is a prerequisite for development of such targeted therapies. Here, we provide a review of the current understanding of the cardiac ANS. The parasympathetic and sympathetic nervous system are composed of higher order cortical centers, brainstem, spinal cord, intrathoracic extracardiac ganglia and intrinsic cardiac ganglia. A series of interacting feedback loops mediates reflex pathways to exert control over the cardiac conduction system and contractile tissue. Further exploration of this complex regulatory system promises to yield neuroscience-based therapeutics for cardiac disease.
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Affiliation(s)
- Peter Hanna
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine, UCLA, Los Angeles, CA.,UCLA Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA
| | - Jeffrey L Ardell
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine, UCLA, Los Angeles, CA.,UCLA Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA
| | - Kalyanam ShivkumarKalyanam
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine, UCLA, Los Angeles, CA.,UCLA Molecular, Cellular & Integrative Physiology Program, UCLA, Los Angeles, CA
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16
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Viruses in connectomics: Viral transneuronal tracers and genetically modified recombinants as neuroscience research tools. J Neurosci Methods 2020; 346:108917. [PMID: 32835704 DOI: 10.1016/j.jneumeth.2020.108917] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/25/2022]
Abstract
Connectomic studies have become 'viral', as viral pathogens have been turned into irreplaceable neuroscience research tools. Highly sensitive viral transneuronal tracing technologies are available, based on the use of alpha-herpesviruses and a rhabdovirus (rabies virus), which function as self-amplifying markers by replicating in recipient neurons. These viruses highly differ with regard to host range, cellular receptors, peripheral uptake, replication, transport direction and specificity. Their characteristics, that make them useful for different purposes, will be highlighted and contrasted. Only transneuronal tracing with rabies virus is entirely specific. The neuroscientist toolbox currently include wild-type alpha-herpesviruses and rabies virus strains enabling polysynaptic tracing of neuronal networks across multiple synapses, as well as genetically modified viral tracers for dual transneuronal tracing, and complementary viral tools including defective and chimeric recombinants that function as single step or monosynaptically restricted tracers, or serve for monitoring and manipulating neuronal activity and gene expression. Methodological issues that are crucial for appropriate use of these technologies will be summarized. Among wild-type and genetically engineered viral tools, rabies virus and chimeric recombinants based on rabies virus as virus backbone are the most powerful, because of the ability of rabies virus to propagate exclusively among connected neurons unidirectionally (retrogradely), without affecting neuronal function. Understanding in depth viral properties is essential for neuroscientists who intend to exploit alpha-herpesviruses, rhabdoviruses or derived recombinants as research tools. Key knowledge will be summarized regarding their cellular receptors, intracellular trafficking and strategies to contrast host defense that explain their different pathophysiology and properties as research tools.
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17
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Liu C, Jiang H, Yu L, S Po S. Vagal Stimulation and Arrhythmias. J Atr Fibrillation 2020; 13:2398. [PMID: 33024499 DOI: 10.4022/jafib.2398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/14/2020] [Accepted: 03/17/2020] [Indexed: 12/14/2022]
Abstract
I mbalance of the sympathetic and parasympathetic nervous systems is probably the most prevalent autonomic mechanism underlying many a rrhythmias . Recently, vagus nerve stimulation ( VNS has emerged as a novel therapeutic modality to treat arrhythmias through its anti adrenergic and anti inflammatory actions . C linical trials applying VNS to the cervical vagus nerve in heart failure pati en ts yielded conflicting results, possibly due to limited understanding of the optimal stimulation parameters for the targeted cardiovascular diseases. Transcutaneous VNS by stimulating the auricular branch of the vagus nerve, has attracted great attention d ue to its noninvasiveness. In this r eview, we summarize current knowledge about the complex relationship between VNS and cardiac arrhythmias and discuss recent advances in using VNS , particularly transcutaneous VNS , to treat arrhythmias.
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Affiliation(s)
- Chengzhe Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous System Research Center of Wuhan Univer s ity, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Hong Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous System Research Center of Wuhan Univer s ity, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Lilei Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiac Autonomic Nervous System Research Center of Wuhan Univer s ity, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Sunny S Po
- Heart Rhythm Institute and Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, O K USA
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18
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Wu P, Vaseghi M. The autonomic nervous system and ventricular arrhythmias in myocardial infarction and heart failure. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2020; 43:172-180. [PMID: 31823401 DOI: 10.1111/pace.13856] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 11/25/2019] [Accepted: 12/05/2019] [Indexed: 12/20/2022]
Abstract
Ventricular arrhythmias (VA) can range in presentation from asymptomatic to cardiac arrest and sudden cardiac death (SCD). Sustained ventricular tachycardias/ventricular fibrillation (VT/VF) are a common cause of SCD in the setting of myocardial infarction (MI) and heart failure. A particularly arrhythmogenic cardiac syncytia in these conditions can be attributed to both sympathetic activation and parasympathetic dysfunction, while appropriate neuromodulation has the potential to reduce occurrence of VT/VF. In this review, we outline the components of the autonomic nervous system that play an important role in normal cardiac electrophysiology and function. In addition, we discuss changes that occur in the setting of cardiac disease including adverse neural remodeling and neurohormonal activation which significantly contribute to propensity for VT/VF. Finally, we review neuromodulation strategies to mitigate VT/VF which predominantly rely on increasing parasympathetic drive and blockade of sympathetic neurotransmission.
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Affiliation(s)
- Perry Wu
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Marmar Vaseghi
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California
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19
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Konstam MA, Udelson JE, Butler J, Klein HU, Parker JD, Teerlink JR, Wedge PM, Saville BR, Ardell JL, Libbus I, DiCarlo LA. Impact of Autonomic Regulation Therapy in Patients with Heart Failure. Circ Heart Fail 2019; 12:e005879. [DOI: 10.1161/circheartfailure.119.005879] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Background:
The ANTHEM-HFrEF (Autonomic Regulation Therapy to Enhance Myocardial Function and Reduce Progression of Heart Failure with Reduced Ejection Fraction) pivotal study is an adaptive, open-label, randomized, controlled study evaluating whether autonomic regulation therapy will benefit patients with advanced HFrEF. While early-phase studies have supported potential use of vagus nerve stimulation to deliver autonomic regulation therapy for HFrEF, results of larger clinical trials have been inconsistent. The ANTHEM-HFrEF study uses a novel design, with adaptive sample size selection, evaluating effects on morbidity and mortality as well as symptoms and function.
Methods:
The ANTHEM-HFrEF study will randomize patients (2:1) to autonomic regulation therapy plus guideline-directed medical therapy, or guideline-directed medical therapy alone. The morbidity and mortality trial utilizes a conventional frequentist approach for analysis of the primary outcome end point—reduction in the composite of cardiovascular death or first HF hospitalization—and a Bayesian adaptive approach toward sample size selection. Embedded within the ANTHEM-HFrEF study is a second trial evaluating improvement in symptoms and function. Symptom/function success will require meeting 2 risk-related conditions (trend for reduced cardiovascular death/HF hospitalization and sufficient freedom from device-related serious adverse events) and 3 efficacy end point components (changes in left ventricular EF, 6-minute walk distance, and Kansas City Cardiomyopathy Questionnaire overall score).
Conclusions:
Vagus nerve stimulation remains a promising, yet unproven treatment in HFrEF. A successful ANTHEM-HFrEF pivotal study would provide an important advance in HFrEF treatment and offer a model for expediting evaluation of new therapies.
Clinical Trial Registration:
URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT03425422.
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Affiliation(s)
- Marvin A. Konstam
- The CardioVascular Center at Tufts Medical Center, Boston, MA (M.A.K., J.E.U.)
| | - James E. Udelson
- The CardioVascular Center at Tufts Medical Center, Boston, MA (M.A.K., J.E.U.)
| | - Javed Butler
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS (J.B.)
| | - Helmut U. Klein
- Department of Medicine, University of Rochester Medical Center, NY (H.U.K.)
| | - John D. Parker
- University of Toronto, Mount Sinai Hospital, Division of Cardiology, Sinai Health Systems and University Health Network, Toronto, Canada (J.D.P.)
| | - John R. Teerlink
- Section of Cardiology, San Francisco Veterans Affairs Medical Center and School of Medicine, University of California (J.R.T.)
| | | | - Benjamin R. Saville
- Berry Consultants LLC, Austin TX and Department of Biostatistics, Vanderbilt University, Nashville TN (B.R.S.)
| | - Jeffrey L. Ardell
- Neurocardiology Center, University of California, Los Angeles (J.L.A.)
| | - Imad Libbus
- LivaNova USA Incorporated, Houston, TX (I.L., L.A.D.)
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20
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Sellers DL, Tan JKY, Pineda JMB, Peeler DJ, Porubsky VL, Olden BR, Salipante SJ, Pun SH. Targeting Ligands Deliver Model Drug Cargo into the Central Nervous System along Autonomic Neurons. ACS NANO 2019; 13:10961-10971. [PMID: 31589023 PMCID: PMC7651855 DOI: 10.1021/acsnano.9b01515] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
While biologic drugs such as proteins, peptides, or nucleic acids have shown promise in the treatment of neurodegenerative diseases, the blood-brain barrier (BBB) severely limits drug delivery to the central nervous system (CNS) after systemic administration. Consequently, drug delivery challenges preclude biological drug candidates from the clinical armamentarium. In order to target drug delivery and uptake into to the CNS, we used an in vivo phage display screen to identify peptides able to target drug-uptake by the vast array of neurons of the autonomic nervous system (ANS). Using next-generation sequencing, we identified 21 candidate targeted ANS-to-CNS uptake ligands (TACL) that enriched bacteriophage accumulation and delivered protein-cargo into the CNS after intraperitoneal (IP) administration. The series of TACL peptides were synthesized and tested for their ability to deliver a model enzyme (NeutrAvidin-horseradish peroxidase fusion) to the brain and spinal cord. Three TACL-peptides facilitated significant active enzyme delivery into the CNS, with limited accumulation in off-target organs. Peptide structure and serum stability is increased when internal cysteine residues are cyclized by perfluoroarylation with decafluorobiphenyl, which increased delivery to the CNS further. TACL-peptide was demonstrated to localize in parasympathetic ganglia neurons in addition to neuronal structures in the hindbrain and spinal cord. By targeting uptake into ANS neurons, we demonstrate the potential for TACL-peptides to bypass the blood-brain barrier and deliver a model drug into the brain and spinal cord.
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Affiliation(s)
- Drew L. Sellers
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, 98195, USA
| | - James-Kevin Y. Tan
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195, USA
| | - Julio Marco B. Pineda
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195, USA
| | - David J. Peeler
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195, USA
| | - Veronica L. Porubsky
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195, USA
| | - Brynn R. Olden
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195, USA
| | - Stephen J. Salipante
- Department of Laboratory Medicine, University of Washington, Seattle, Washington 98195, United States
| | - Suzie H. Pun
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195, USA
- Molecular Engineering and Sciences Institute, University of Washington, Seattle, Washington, 98195, USA
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21
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Liu DS, Xu TL. Cell-Type Identification in the Autonomic Nervous System. Neurosci Bull 2018; 35:145-155. [PMID: 30171526 DOI: 10.1007/s12264-018-0284-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/31/2018] [Indexed: 11/25/2022] Open
Abstract
The autonomic nervous system controls various internal organs and executes crucial functions through sophisticated neural connectivity and circuits. Its dysfunction causes an imbalance of homeostasis and numerous human disorders. In the past decades, great efforts have been made to study the structure and functions of this system, but so far, our understanding of the classification of autonomic neuronal subpopulations remains limited and a precise map of their connectivity has not been achieved. One of the major challenges that hinder rapid progress in these areas is the complexity and heterogeneity of autonomic neurons. To facilitate the identification of neuronal subgroups in the autonomic nervous system, here we review the well-established and cutting-edge technologies that are frequently used in peripheral neuronal tracing and profiling, and discuss their operating mechanisms, advantages, and targeted applications.
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Affiliation(s)
- Di-Shi Liu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Tian-Le Xu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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22
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Garrott K, Dyavanapalli J, Cauley E, Dwyer MK, Kuzmiak-Glancy S, Wang X, Mendelowitz D, Kay MW. Chronic activation of hypothalamic oxytocin neurons improves cardiac function during left ventricular hypertrophy-induced heart failure. Cardiovasc Res 2018; 113:1318-1328. [PMID: 28472396 DOI: 10.1093/cvr/cvx084] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 04/28/2017] [Indexed: 01/07/2023] Open
Abstract
Aims A distinctive hallmark of heart failure (HF) is autonomic imbalance, consisting of increased sympathetic activity, and decreased parasympathetic tone. Recent work suggests that activation of hypothalamic oxytocin (OXT) neurons could improve autonomic balance during HF. We hypothesized that a novel method of chronic selective activation of hypothalamic OXT neurons will improve cardiac function and reduce inflammation and fibrosis in a rat model of HF. Methods and results Two groups of male Sprague-Dawley rats underwent trans-ascending aortic constriction (TAC) to induce left ventricular (LV) hypertrophy that progresses to HF. In one TAC group, OXT neurons in the paraventricular nucleus of the hypothalamus were chronically activated by selective expression and activation of excitatory DREADDs receptors with daily injections of clozapine N-oxide (CNO) (TAC + OXT). Two additional age-matched groups received either saline injections (Control) or CNO injections for excitatory DREADDs activation (OXT NORM). Heart rate (HR), LV developed pressure (LVDP), and coronary flow rate were measured in isolated heart experiments. Isoproterenol (0.01 nM-1.0 µM) was administered to evaluate β-adrenergic sensitivity. We found that increases in cellular hypertrophy and myocardial collagen density in TAC were blunted in TAC + OXT animals. Inflammatory cytokine IL-1β expression was more than twice higher in TAC than all other hearts. LVDP, rate pressure product (RPP), contractility, and relaxation were depressed in TAC compared with all other groups. The response of TAC and TAC + OXT hearts to isoproterenol was blunted, with no significant increase in RPP, contractility, or relaxation. However, HR in TAC + OXT animals increased to match Control at higher doses of isoproterenol. Conclusions Activation of hypothalamic OXT neurons to elevate parasympathetic tone reduced cellular hypertrophy, levels of IL-1β, and fibrosis during TAC-induced HF in rats. Cardiac contractility parameters were significantly higher in TAC + OXT compared with TAC animals. HR sensitivity, but not contractile sensitivity, to β-adrenergic stimulation was improved in TAC + OXT hearts.
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Affiliation(s)
- Kara Garrott
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800?22nd Street NW, Suite 5000, Washington, DC 20052, USA
| | - Jhansi Dyavanapalli
- Department of Pharmacology and Physiology, The George Washington University, Ross Hall, 2300 Eye St. NW, Suite 640, Washington, DC 20037, USA
| | - Edmund Cauley
- Department of Pharmacology and Physiology, The George Washington University, Ross Hall, 2300 Eye St. NW, Suite 640, Washington, DC 20037, USA
| | - Mary Kate Dwyer
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800?22nd Street NW, Suite 5000, Washington, DC 20052, USA
| | - Sarah Kuzmiak-Glancy
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800?22nd Street NW, Suite 5000, Washington, DC 20052, USA
| | - Xin Wang
- Department of Pharmacology and Physiology, The George Washington University, Ross Hall, 2300 Eye St. NW, Suite 640, Washington, DC 20037, USA
| | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University, Ross Hall, 2300 Eye St. NW, Suite 640, Washington, DC 20037, USA
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, GWU Science and Engineering Hall, 800?22nd Street NW, Suite 5000, Washington, DC 20052, USA
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23
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Vaseghi M, Salavatian S, Rajendran PS, Yagishita D, Woodward WR, Hamon D, Yamakawa K, Irie T, Habecker BA, Shivkumar K. Parasympathetic dysfunction and antiarrhythmic effect of vagal nerve stimulation following myocardial infarction. JCI Insight 2017; 2:86715. [PMID: 28814663 DOI: 10.1172/jci.insight.86715] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 07/06/2017] [Indexed: 01/22/2023] Open
Abstract
Myocardial infarction causes sympathetic activation and parasympathetic dysfunction, which increase risk of sudden death due to ventricular arrhythmias. Mechanisms underlying parasympathetic dysfunction are unclear. The aim of this study was to delineate consequences of myocardial infarction on parasympathetic myocardial neurotransmitter levels and the function of parasympathetic cardiac ganglia neurons, and to assess electrophysiological effects of vagal nerve stimulation on ventricular arrhythmias in a chronic porcine infarct model. While norepinephrine levels decreased, cardiac acetylcholine levels remained preserved in border zones and viable myocardium of infarcted hearts. In vivo neuronal recordings demonstrated abnormalities in firing frequency of parasympathetic neurons of infarcted animals. Neurons that were activated by parasympathetic stimulation had low basal firing frequency, while neurons that were suppressed by left vagal nerve stimulation had abnormally high basal activity. Myocardial infarction increased sympathetic inputs to parasympathetic convergent neurons. However, the underlying parasympathetic cardiac neuronal network remained intact. Augmenting parasympathetic drive with vagal nerve stimulation reduced ventricular arrhythmia inducibility by decreasing ventricular excitability and heterogeneity of repolarization of infarct border zones, an area with known proarrhythmic potential. Preserved acetylcholine levels and intact parasympathetic neuronal pathways can explain the electrical stabilization of infarct border zones with vagal nerve stimulation, providing insight into its antiarrhythmic benefit.
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Affiliation(s)
- Marmar Vaseghi
- Cardiac Arrhythmia Center.,Neurocardiology Research Center of Excellence, and.,Molecular Cellular and Integrative Physiology Interdepartmental Program, UCLA, Los Angeles, California, USA
| | - Siamak Salavatian
- Cardiac Arrhythmia Center.,Neurocardiology Research Center of Excellence, and.,Molecular Cellular and Integrative Physiology Interdepartmental Program, UCLA, Los Angeles, California, USA
| | - Pradeep S Rajendran
- Cardiac Arrhythmia Center.,Neurocardiology Research Center of Excellence, and.,Molecular Cellular and Integrative Physiology Interdepartmental Program, UCLA, Los Angeles, California, USA
| | - Daigo Yagishita
- Cardiac Arrhythmia Center.,Neurocardiology Research Center of Excellence, and
| | | | - David Hamon
- Cardiac Arrhythmia Center.,Neurocardiology Research Center of Excellence, and
| | | | - Tadanobu Irie
- Cardiac Arrhythmia Center.,Neurocardiology Research Center of Excellence, and
| | - Beth A Habecker
- Department of Physiology & Pharmacology and.,Department of Medicine Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Kalyanam Shivkumar
- Cardiac Arrhythmia Center.,Neurocardiology Research Center of Excellence, and.,Molecular Cellular and Integrative Physiology Interdepartmental Program, UCLA, Los Angeles, California, USA
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24
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Hanna P, Rajendran PS, Ajijola OA, Vaseghi M, Andrew Armour J, Ardell JL, Shivkumar K. Cardiac neuroanatomy - Imaging nerves to define functional control. Auton Neurosci 2017; 207:48-58. [PMID: 28802636 DOI: 10.1016/j.autneu.2017.07.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 07/22/2017] [Accepted: 07/28/2017] [Indexed: 01/08/2023]
Abstract
The autonomic nervous system regulates normal cardiovascular function and plays a critical role in the pathophysiology of cardiovascular disease. Further understanding of the interplay between the autonomic nervous system and cardiovascular system holds promise for the development of neuroscience-based cardiovascular therapeutics. To this end, techniques to image myocardial innervation will help provide a basis for understanding the fundamental underpinnings of cardiac neural control. In this review, we detail the evolution of gross and microscopic anatomical studies for functional mapping of cardiac neuroanatomy.
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Affiliation(s)
- Peter Hanna
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Pradeep S Rajendran
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Molecular, Cellular & Integrative Physiology Program, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Olujimi A Ajijola
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Marmar Vaseghi
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - J Andrew Armour
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Jefrrey L Ardell
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Molecular, Cellular & Integrative Physiology Program, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Kalyanam Shivkumar
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Molecular, Cellular & Integrative Physiology Program, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.
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25
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Jungen C, Scherschel K, Eickholt C, Kuklik P, Klatt N, Bork N, Salzbrunn T, Alken F, Angendohr S, Klene C, Mester J, Klöcker N, Veldkamp MW, Schumacher U, Willems S, Nikolaev VO, Meyer C. Disruption of cardiac cholinergic neurons enhances susceptibility to ventricular arrhythmias. Nat Commun 2017; 8:14155. [PMID: 28128201 PMCID: PMC5290156 DOI: 10.1038/ncomms14155] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 11/28/2016] [Indexed: 12/19/2022] Open
Abstract
The parasympathetic nervous system plays an important role in the pathophysiology of atrial fibrillation. Catheter ablation, a minimally invasive procedure deactivating abnormal firing cardiac tissue, is increasingly becoming the therapy of choice for atrial fibrillation. This is inevitably associated with the obliteration of cardiac cholinergic neurons. However, the impact on ventricular electrophysiology is unclear. Here we show that cardiac cholinergic neurons modulate ventricular electrophysiology. Mechanical disruption or pharmacological blockade of parasympathetic innervation shortens ventricular refractory periods, increases the incidence of ventricular arrhythmia and decreases ventricular cAMP levels in murine hearts. Immunohistochemistry confirmed ventricular cholinergic innervation, revealing parasympathetic fibres running from the atria to the ventricles parallel to sympathetic fibres. In humans, catheter ablation of atrial fibrillation, which is accompanied by accidental parasympathetic and concomitant sympathetic denervation, raises the burden of premature ventricular complexes. In summary, our results demonstrate an influence of cardiac cholinergic neurons on the regulation of ventricular function and arrhythmogenesis. Catheter ablation is a common therapy for atrial fibrillation but disrupts cardiac cholinergic neurons. Here the authors report that cholinergic neurons innervate heart ventricles and show that their ablation leads to increased susceptibility to ventricular arrhythmias in mouse models and in patients.
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Affiliation(s)
- Christiane Jungen
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 13347 Berlin, Germany
| | - Katharina Scherschel
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 13347 Berlin, Germany
| | - Christian Eickholt
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Pawel Kuklik
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Niklas Klatt
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 13347 Berlin, Germany
| | - Nadja Bork
- DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 13347 Berlin, Germany.,Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Tim Salzbrunn
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Fares Alken
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Stephan Angendohr
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Christiane Klene
- Department of Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Janos Mester
- Department of Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Nikolaj Klöcker
- Institute of Neural and Sensory Physiology, Medical Faculty, University of Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Marieke W Veldkamp
- Academic Medical Center, University of Amsterdam, Department of Clinical and Experimental Cardiology, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Udo Schumacher
- Institute of Anatomy and Experimental Morphology, University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Stephan Willems
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 13347 Berlin, Germany
| | - Viacheslav O Nikolaev
- DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 13347 Berlin, Germany.,Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Christian Meyer
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart Center, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 13347 Berlin, Germany
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Verberne AJM, Korim WS, Sabetghadam A, Llewellyn-Smith IJ. Adrenaline: insights into its metabolic roles in hypoglycaemia and diabetes. Br J Pharmacol 2016; 173:1425-37. [PMID: 26896587 DOI: 10.1111/bph.13458] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 01/20/2016] [Accepted: 02/11/2016] [Indexed: 01/05/2023] Open
Abstract
Adrenaline is a hormone that has profound actions on the cardiovascular system and is also a mediator of the fight-or-flight response. Adrenaline is now increasingly recognized as an important metabolic hormone that helps mobilize energy stores in the form of glucose and free fatty acids in preparation for physical activity or for recovery from hypoglycaemia. Recovery from hypoglycaemia is termed counter-regulation and involves the suppression of endogenous insulin secretion, activation of glucagon secretion from pancreatic α-cells and activation of adrenaline secretion. Secretion of adrenaline is controlled by presympathetic neurons in the rostroventrolateral medulla, which are, in turn, under the control of central and/or peripheral glucose-sensing neurons. Adrenaline is particularly important for counter-regulation in individuals with type 1 (insulin-dependent) diabetes because these patients do not produce endogenous insulin and also lose their ability to secrete glucagon soon after diagnosis. Type 1 diabetic patients are therefore critically dependent on adrenaline for restoration of normoglycaemia and attenuation or loss of this response in the hypoglycaemia unawareness condition can have serious, sometimes fatal, consequences. Understanding the neural control of hypoglycaemia-induced adrenaline secretion is likely to identify new therapeutic targets for treating this potentially life-threatening condition.
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Affiliation(s)
- A J M Verberne
- Clinical Pharmacology and Therapeutics Unit, Department of Medicine, Austin Health, University of Melbourne, Heidelberg, VIC, Australia
| | - W S Korim
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - A Sabetghadam
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - I J Llewellyn-Smith
- Cardiovascular Medicine and Human Physiology, Flinders University, Bedford Park, SA, Australia
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Ardell JL, Rajendran PS, Nier HA, KenKnight BH, Armour JA. Central-peripheral neural network interactions evoked by vagus nerve stimulation: functional consequences on control of cardiac function. Am J Physiol Heart Circ Physiol 2015; 309:H1740-52. [PMID: 26371171 DOI: 10.1152/ajpheart.00557.2015] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/10/2015] [Indexed: 12/19/2022]
Abstract
Using vagus nerve stimulation (VNS), we sought to determine the contribution of vagal afferents to efferent control of cardiac function. In anesthetized dogs, the right and left cervical vagosympathetic trunks were stimulated in the intact state, following ipsilateral or contralateral vagus nerve transection (VNTx), and then following bilateral VNTx. Stimulations were performed at currents from 0.25 to 4.0 mA, frequencies from 2 to 30 Hz, and a 500-μs pulse width. Right or left VNS evoked significantly greater current- and frequency-dependent suppression of chronotropic, inotropic, and lusitropic function subsequent to sequential VNTx. Bradycardia threshold was defined as the current first required for a 5% decrease in heart rate. The threshold for the right vs. left vagus-induced bradycardia in the intact state (2.91 ± 0.18 and 3.47 ± 0.20 mA, respectively) decreased significantly with right VNTx (1.69 ± 0.17 mA for right and 3.04 ± 0.27 mA for left) and decreased further following bilateral VNTx (1.29 ± 0.16 mA for right and 1.74 ± 0.19 mA for left). Similar effects were observed following left VNTx. The thresholds for afferent-mediated effects on cardiac parameters were 0.62 ± 0.04 and 0.65 ± 0.06 mA with right and left VNS, respectively, and were reflected primarily as augmentation. Afferent-mediated tachycardias were maintained following β-blockade but were eliminated by VNTx. The increased effectiveness and decrease in bradycardia threshold with sequential VNTx suggest that 1) vagal afferents inhibit centrally mediated parasympathetic efferent outflow and 2) the ipsilateral and contralateral vagi exert a substantial buffering capacity. The intact threshold reflects the interaction between multiple levels of the cardiac neural hierarchy.
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Affiliation(s)
- Jeffrey L Ardell
- Neurocardiology Research Center of Excellence, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California; Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California; Molecular, Cellular, and Integrative Physiology Program, University of California-Los Angeles, Los Angeles, California;
| | - Pradeep S Rajendran
- Neurocardiology Research Center of Excellence, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California; Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California; Molecular, Cellular, and Integrative Physiology Program, University of California-Los Angeles, Los Angeles, California
| | - Heath A Nier
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee; and
| | | | - J Andrew Armour
- Neurocardiology Research Center of Excellence, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California; Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California
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28
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Yamakawa K, Rajendran PS, Takamiya T, Yagishita D, So EL, Mahajan A, Shivkumar K, Vaseghi M. Vagal nerve stimulation activates vagal afferent fibers that reduce cardiac efferent parasympathetic effects. Am J Physiol Heart Circ Physiol 2015; 309:H1579-90. [PMID: 26371172 DOI: 10.1152/ajpheart.00558.2015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/10/2015] [Indexed: 12/13/2022]
Abstract
Vagal nerve stimulation (VNS) has been shown to have antiarrhythmic effects, but many of these benefits were demonstrated in the setting of vagal nerve decentralization. The purpose of this study was to evaluate the role of afferent fiber activation during VNS on efferent control of cardiac hemodynamic and electrophysiological parameters. In 37 pigs a 56-electrode sock was placed over the ventricles to record local activation recovery intervals (ARIs), a surrogate of action potential duration. In 12 of 37 animals atropine was given systemically. Right and left VNS were performed under six conditions: both vagal trunks intact (n = 25), ipsilateral right (n = 11), ipsilateral left (n = 14), contralateral right (n = 7), contralateral left (n = 10), and bilateral (n = 25) vagal nerve transection (VNTx). Unilateral VNTx significantly affected heart rate, PR interval, Tau, and global ARIs. Right VNS after ipsilateral VNTx had augmented effects on hemodynamic parameters and increase in ARI, while subsequent bilateral VNTx did not significantly modify this effect (%change in ARI in intact condition 2.2 ± 0.9% vs. ipsilateral VNTx 5.3 ± 1.7% and bilateral VNTx 5.3 ± 0.8%, P < 0.05). Left VNS after left VNTx tended to increase its effects on hemodynamics and ARI response (P = 0.07), but only after bilateral VNTx did these changes reach significance (intact 1.1 ± 0.5% vs. ipsilateral VNTx 3.6 ± 0.7% and bilateral VNTx 6.6 ± 1.6%, P < 0.05 vs. intact). Contralateral VNTx did not modify VNS response. The effect of atropine on ventricular ARI was similar to bilateral VNTx. We found that VNS activates afferent fibers in the ipsilateral vagal nerve, which reflexively inhibit cardiac parasympathetic efferent electrophysiological and hemodynamic effects.
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Affiliation(s)
- Kentaro Yamakawa
- University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and Department of Anesthesiology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California
| | - Pradeep S Rajendran
- University of California Los Angeles Cardiac Arrhythmia Center, Los Angeles, California; University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and
| | - Tatsuo Takamiya
- University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and Department of Anesthesiology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California
| | - Daigo Yagishita
- University of California Los Angeles Cardiac Arrhythmia Center, Los Angeles, California; University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and
| | - Eileen L So
- University of California Los Angeles Cardiac Arrhythmia Center, Los Angeles, California; University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and
| | - Aman Mahajan
- University of California Los Angeles Cardiac Arrhythmia Center, Los Angeles, California; University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and Department of Anesthesiology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California
| | - Kalyanam Shivkumar
- University of California Los Angeles Cardiac Arrhythmia Center, Los Angeles, California; University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and
| | - Marmar Vaseghi
- University of California Los Angeles Cardiac Arrhythmia Center, Los Angeles, California; University of California Los Angeles Neurocardiology Research Center of Excellence, Los Angeles, California; and
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Ciriello J. Sex and estrogen affect the distribution of urocortin-1 immunoreactivity in brainstem autonomic nuclei of the rat. Brain Res Bull 2015; 116:81-92. [PMID: 26146233 DOI: 10.1016/j.brainresbull.2015.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/27/2015] [Accepted: 06/29/2015] [Indexed: 12/30/2022]
Abstract
Urocortin-1 (UCN-1), a neuropeptide closely related to the hypothalamic hormone corticotropin-releasing factor, has been associated with stress, feeding behaviors, cardiovascular control, and to exhibit functional gender differences. This study was done to investigate whether estrogen (E; 17β-estradiol) treatment (9 weeks) altered UCN-1 immunoreactivity in brainstem autonomic nuclei in female Wistar rats. Experiments were done in age matched adult males (controls), females (intact), and ovariectomized (OVX) only and OVX+E (30pg/ml plasma) treated females. All animals received intracerebroventricular injections of colchicine and were then perfused transcardially with Zamboni's fixative. Coronal brainstem sections (40μm) were cut and processed immunohistochemically for UCN-1. In males, moderate UCN-1 fiber labeling was found in the nucleus of the solitary tract (NTS) and throughout the rostral ventral lateral medulla (RVLM). Additionally, a few UCN-1 immunoreactive neurons were observed in hypoglossal nucleus (XII), facial nucleus (FN) and nucleus ambiguus (Amb). In intact females and OVX+E females, fewer UCN-1 labeled fibers were found within NTS compared to males. In contrast, the RVLM was more densely innervated in the female cases. Furthermore, in both intact and OVX+E females UCN-1 labeled neurons were found not only within Amb, FN and XII, but also within NTS, RVLM and nucleus raphé pallidus (RP). In OVX only animals, moderate to dense UCN-1 fiber labeling was observed in the NTS complex and throughout RVLM compared to males and the other female groups. However, in contrast to all other groups, UCN-1 labeled neurons were found in greater number within Amb, FN, NTS, dorsal motor nucleus of the vagus, XII, RVLM, magnocellular reticular nucleus and RP. These data not only suggest that sex differences exist in the distribution of UCN-1 within brainstem autonomic areas, but that circulating level of E may play an important role with regards to the function of these UCN-1 neurons during stress responses.
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Affiliation(s)
- John Ciriello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada.
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30
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Mundell NA, Beier KT, Pan YA, Lapan SW, Göz Aytürk D, Berezovskii VK, Wark AR, Drokhlyansky E, Bielecki J, Born RT, Schier AF, Cepko CL. Vesicular stomatitis virus enables gene transfer and transsynaptic tracing in a wide range of organisms. J Comp Neurol 2015; 523:1639-63. [PMID: 25688551 PMCID: PMC4458151 DOI: 10.1002/cne.23761] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 02/03/2015] [Accepted: 02/10/2015] [Indexed: 12/20/2022]
Abstract
Current limitations in technology have prevented an extensive analysis of the connections among neurons, particularly within nonmammalian organisms. We developed a transsynaptic viral tracer originally for use in mice, and then tested its utility in a broader range of organisms. By engineering the vesicular stomatitis virus (VSV) to encode a fluorophore and either the rabies virus glycoprotein (RABV‐G) or its own glycoprotein (VSV‐G), we created viruses that can transsynaptically label neuronal circuits in either the retrograde or anterograde direction, respectively. The vectors were investigated for their utility as polysynaptic tracers of chicken and zebrafish visual pathways. They showed patterns of connectivity consistent with previously characterized visual system connections, and revealed several potentially novel connections. Further, these vectors were shown to infect neurons in several other vertebrates, including Old and New World monkeys, seahorses, axolotls, and Xenopus. They were also shown to infect two invertebrates, Drosophila melanogaster, and the box jellyfish, Tripedalia cystophora, a species previously intractable for gene transfer, although no clear evidence of transsynaptic spread was observed in these species. These vectors provide a starting point for transsynaptic tracing in most vertebrates, and are also excellent candidates for gene transfer in organisms that have been refractory to other methods. J. Comp. Neurol. 523:1639–1663, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Nathan A Mundell
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, 02115.,Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, 02115
| | - Kevin T Beier
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, 02115.,Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, 02115
| | - Y Albert Pan
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, 01238
| | - Sylvain W Lapan
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, 02115.,Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, 02115
| | - Didem Göz Aytürk
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, 02115.,Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, 02115
| | | | - Abigail R Wark
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, 02115
| | - Eugene Drokhlyansky
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, 02115.,Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, 02115
| | - Jan Bielecki
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, 93106
| | - Richard T Born
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, 02115
| | - Alexander F Schier
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, 01238
| | - Constance L Cepko
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, 02115.,Department of Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, 02115
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Beier KT, Saunders AB, Oldenburg IA, Sabatini BL, Cepko CL. Vesicular stomatitis virus with the rabies virus glycoprotein directs retrograde transsynaptic transport among neurons in vivo. Front Neural Circuits 2013; 7:11. [PMID: 23403489 PMCID: PMC3566411 DOI: 10.3389/fncir.2013.00011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/20/2013] [Indexed: 12/24/2022] Open
Abstract
Defining the connections among neurons is critical to our understanding of the structure and function of the nervous system. Recombinant viruses engineered to transmit across synapses provide a powerful approach for the dissection of neuronal circuitry in vivo. We recently demonstrated that recombinant vesicular stomatitis virus (VSV) can be endowed with anterograde or retrograde transsynaptic tracing ability by providing the virus with different glycoproteins. Here we extend the characterization of the transmission and gene expression of recombinant VSV (rVSV) with the rabies virus glycoprotein (RABV-G), and provide examples of its activity relative to the anterograde transsynaptic tracer form of rVSV. rVSV with RABV-G was found to drive strong expression of transgenes and to spread rapidly from neuron to neuron in only a retrograde manner. Depending upon how the RABV-G was delivered, VSV served as a polysynaptic or monosynaptic tracer, or was able to define projections through axonal uptake and retrograde transport. In animals co-infected with rVSV in its anterograde form, rVSV with RABV-G could be used to begin to characterize the similarities and differences in connections to different areas. rVSV with RABV-G provides a flexible, rapid, and versatile tracing tool that complements the previously described VSV-based anterograde transsynaptic tracer.
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Affiliation(s)
- Kevin T Beier
- Department of Genetics and Department of Ophthalmology, Harvard Medical School, Harvard University and Howard Hughes Medical Institute Boston, MA, USA
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33
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Dejongste MJ, Hautvast RW, Ruiters MH, Ter Horst GJ. Spinal Cord Stimulation and the Induction of c-fos and Heat Shock Protein 72 in the Central Nervous System of Rats. Neuromodulation 2012; 1:73-84. [PMID: 22150939 DOI: 10.1111/j.1525-1403.1998.tb00020.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For more than a decade, spinal cord stimulation (SCS) has been used as an adjuvant treatment for patients who are unresponsive to conventional therapies for angina pectoris. Many studies showed that SCS has both electro-analgesic and anti-ischemic effects. Nonetheless, the biological substrates by which SCS acts have not yet been unraveled, although recently areas in the brain have been described that show changes in blood flow, following SCS, and during provocation of angina. In search of a putative mechanism of action of SCS, we hypothesized that SCS affects processing of nociceptive information within the central nervous system (CNS). Moreover, it may alter the limbic system activity that maintains the balance between sympathetic and parasympathetic activity in the heart. Hence, we have developed a rat model to investigate its suitability for studying the induction of neural activity during SCS. To characterize neural activity, we used the expression of both the immediate early gene c-fos and the heat shock protein 72 (HSP72). c-Fos was used to identify structures in the CNS affected by SCS, and HSP72 was applied in order to ascertain whether SCS might operate as a stressor. In 20 halothane-anesthetized male Wistar rats, two electrodes were placed epidurally, one at the C7 level and the other at the T2 level. Two days after surgery, the rats were either stimulated "treated" animals, n = 10) or used as controls ("unstimulated" = "sham," n = 10) in random order. Furthermore, we studied the effect of SCS on behavior in five treated and five control rats. Three hours after stimulation, the rats were euthanized and the brain and spinal cord were removed. The treated group showed regional increased c-fos expression in regions of the limbic system (periaqueductal gray, paraventricular hypothalamic nucleus, paraventricular thalamic nucleus, central amygdala, agranular and dysgranular insular cortex, (peri)ambiguus, nucleus tractus solitarius, and spinal cord) that are involved in the processing of pain and cardiovascular regulation, among other things. Moreover, in both treated rats and controls, HSP72-expression was found in the endothelium of the enthorhinal cortex, the amygdala, and the ventral hypothalamus, but not in the neurons. Finally, treated animals were significantly more alert and active than controls. In conclusion, the rat model we developed appears to be suitable for studying potential mechanisms through which SCS may act. In addition, SCS affects c-fos expression in specific parts of the brain known to be involved in regulation of pain and emotions. HSP72-expression is limited to the endothelium of certain parts of the CNS and thereby excludes physical stress effects as a potential mechanism of SCS.
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Affiliation(s)
- M J Dejongste
- Dept. of Cardiology, Thoraxcenter.Biomedical Technology Center, andBiological Psychiatry, University Hospital of Groningen, Groningen, The Netherlands
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Tan W, Sherman D, Turesson J, Shao XM, Janczewski WA, Feldman JL. Reelin demarcates a subset of pre-Bötzinger complex neurons in adult rat. J Comp Neurol 2012; 520:606-19. [PMID: 21858819 DOI: 10.1002/cne.22753] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Identification of two markers of neurons in the pre-Bötzinger complex (pre-BötC), the neurokinin 1 receptor (NK1R) and somatostatin (Sst) peptide, has been of great utility in understanding the essential role of the pre-BötC in breathing. Recently, the transcription factor dbx1 was identified as a critical, but transient, determinant of glutamatergic pre-BötC neurons. Here, to identify additional markers, we constructed and screened a single-cell subtractive cDNA library from pre-BötC inspiratory neurons. We identified the glycoprotein reelin as a potentially useful marker, because it is expressed in distinct populations of pre-BötC and inspiratory bulbospinal ventral respiratory group (ibsVRG) neurons. Reelin ibsVRG neurons were larger (27.1 ± 3.8 μm in diameter) and located more caudally (>12.8 mm caudal to Bregma) than reelin pre-BötC neurons (15.5 ± 2.4 μm in diameter, <12.8 mm rostral to Bregma). Pre-BötC reelin neurons coexpress NK1R and Sst. Reelin neurons were also found in the parahypoglossal and dorsal parafacial regions, pontine respiratory group, and ventromedial medulla. Reelin-deficient (Reeler) mice exhibited impaired respones to hypoxia compared with littermate controls. We suggest that reelin is a useful molecular marker for pre-BötC neurons in adult rodents and may play a functional role in pre-BötC microcircuits.
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Affiliation(s)
- Wenbin Tan
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
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35
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Harvey RD. Muscarinic receptor agonists and antagonists: effects on cardiovascular function. Handb Exp Pharmacol 2012:299-316. [PMID: 22222704 DOI: 10.1007/978-3-642-23274-9_13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Muscarinic receptor activation plays an essential role in parasympathetic regulation of cardiovascular function. The primary effect of parasympathetic stimulation is to decrease cardiac output by inhibiting heart rate. However, pharmacologically, muscarinic agonists are actually capable of producing both inhibitory and stimulatory effects on the heart as well as vasculature. This reflects the fact that muscarinic receptors are expressed throughout the cardiovascular system, even though they are not always involved in mediating parasympathetic responses. In the heart, in addition to regulating heart rate by altering the electrical activity of the sinoatrial node, activation of M₂ receptors can affect conduction of electrical impulses through the atrioventricular node. These same receptors can also regulate the electrical and mechanical activity of the atria and ventricles. In the vasculature, activation of M₃ and M₅ receptors in epithelial cells can cause vasorelaxation, while activation of M₁ or M₃ receptors in vascular smooth muscle cells can cause vasoconstriction in the absence of endothelium. This review focuses on our current understanding of the signaling mechanisms involved in mediating these responses.
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Affiliation(s)
- Robert D Harvey
- Department of Pharmacology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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36
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Denk W, Briggman KL, Helmstaedter M. Structural neurobiology: missing link to a mechanistic understanding of neural computation. Nat Rev Neurosci 2012; 13:351-8. [PMID: 22353782 DOI: 10.1038/nrn3169] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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37
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Abstract
Powerful transneuronal tracing technologies exploit the ability of some neurotropic viruses to travel across neuronal pathways and to function as self-amplifying markers. Rabies virus is the only viral tracer that is entirely specific, as it propagates exclusively between connected neurons by strictly unidirectional (retrograde) transneuronal transfer, allowing for the stepwise identification of neuronal connections of progressively higher order. Transneuronal tracing studies in primates and rodent models prior to the development of clinical disease have provided valuable information on rabies pathogenesis. We have shown that rabies virus propagation occurs at chemical synapses but not via gap junctions or cell-to-cell spread. Infected neurons remain viable, as they can express their neurotransmitters and cotransport other tracers. Axonal transport occurs at high speed, and all populations of the same synaptic order are infected simultaneously regardless of their neurotransmitters, synaptic strength, and distance, showing that rabies virus receptors are ubiquitously distributed within the CNS. Conversely, in the peripheral nervous system, rabies virus receptors are present only on motor endplates and motor axons, since uptake and transneuronal transmission to the CNS occur exclusively via the motor route, while sensory and autonomic endings are not infected. Infection of sensory and autonomic ganglia requires longer incubation times, as it reflects centrifugal propagation from the CNS to the periphery, via polysynaptic connections from sensory and autonomic neurons to the initially infected motoneurons. Virus is recovered from end organs only after the development of rabies because anterograde spread to end organs is likely mediated by passive diffusion, rather than active transport mechanisms.
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Affiliation(s)
- Gabriella Ugolini
- Neurobiologie et Développement, UPR3294 CNRS, Institut de Neurobiologie Alfred Fessard, 91198 Gif-sur-Yvette, France
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Merico A, Cavinato M. Autonomic dysfunction in the early stage of ALS with bulbar involvement. ACTA ACUST UNITED AC 2011; 12:363-7. [PMID: 21623664 DOI: 10.3109/17482968.2011.584628] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Our objective was to assess the autonomic function of ALS patients with and without bulbar signs to characterize dysautonomia in ALS disease. Standard autonomic tests and spectral analysis of heart rate variability (HRV), reflecting changes in the sympathovagal balance, were examined in 33 ALS patients (14 with bulbar signs) and 30 controls. Results showed that in the supine position, ALS patients had significantly lower total power and absolute values of high-frequency power indicating a depressed sinus arrhythmia. Patients with bulbar signs showed more marked autonomic alterations at rest. Tilting did not induce the expected increase in low-frequency and decrease in high-frequency power of HRV in all patients. No correlation was found between autonomic tests and clinical parameters. Our findings suggest an early subclinical involvement of the autonomic system in ALS, particularly affecting parasympathetic cardiac control. Patients with prominent bulbar signs show a more severe autonomic dysfunction under resting conditions.
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Affiliation(s)
- Antonio Merico
- Department of Neurophysiology, San Camillo Foundation, Institute of Care and Research , Venice , Italy
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39
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Ugolini G. Advances in viral transneuronal tracing. J Neurosci Methods 2010; 194:2-20. [DOI: 10.1016/j.jneumeth.2009.12.001] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 11/28/2009] [Accepted: 12/03/2009] [Indexed: 10/20/2022]
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40
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Teashirt 3 regulates development of neurons involved in both respiratory rhythm and airflow control. J Neurosci 2010; 30:9465-76. [PMID: 20631175 DOI: 10.1523/jneurosci.1765-10.2010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neonatal breathing in mammals involves multiple neuronal circuits, but its genetic basis remains unclear. Mice deficient for the zinc finger protein Teashirt 3 (TSHZ3) fail to breathe and die at birth. Tshz3 is expressed in multiple areas of the brainstem involved in respiration, including the pre-Bötzinger complex (preBötC), the embryonic parafacial respiratory group (e-pF), and cranial motoneurons that control the upper airways. Tshz3 inactivation led to pronounced cell death of motoneurons in the nucleus ambiguus and induced strong alterations of rhythmogenesis in the e-pF oscillator. In contrast, the preBötC oscillator appeared to be unaffected. These deficits result in impaired upper airway function, abnormal central respiratory rhythm generation, and altered responses to pH changes. Thus, a single gene, Tshz3, controls the development of diverse components of the circuitry required for breathing.
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Hou L, Tang H, Chen Y, Wang L, Zhou X, Rong W, Wang J. Presynaptic modulation of tonic and respiratory inputs to cardiovagal motoneurons by substance P. Brain Res 2009; 1284:31-40. [DOI: 10.1016/j.brainres.2009.05.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 05/19/2009] [Accepted: 05/25/2009] [Indexed: 02/05/2023]
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42
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Suzuki S, Yanagita S, Amemiya S, Kato Y, Kubota N, Ryushi T, Kita I. Effects of negative air ions on activity of neural substrates involved in autonomic regulation in rats. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2008; 52:481-489. [PMID: 18188611 DOI: 10.1007/s00484-007-0143-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 11/30/2007] [Accepted: 12/18/2007] [Indexed: 05/25/2023]
Abstract
The neural mechanism by which negative air ions (NAI) mediate the regulation of autonomic nervous system activity is still unknown. We examined the effects of NAI on physiological responses, such as blood pressure (BP), heart rate (HR), and heart rate variability (HRV) as well as neuronal activity, in the paraventricular nucleus of the hypothalamus (PVN), locus coeruleus (LC), nucleus ambiguus (NA), and nucleus of the solitary tract (NTS) with c-Fos immunohistochemistry in anesthetized, spontaneously breathing rats. In addition, we performed cervical vagotomy to reveal the afferent pathway involved in mediating the effects of NAI on autonomic regulation. NAI significantly decreased BP and HR, and increased HF power of the HRV spectrum. Significant decreases in c-Fos positive nuclei in the PVN and LC, and enhancement of c-Fos expression in the NA and NTS were induced by NAI. After vagotomy, these physiological and neuronal responses to NAI were not observed. These findings suggest that NAI can modulate autonomic regulation through inhibition of neuronal activity in PVN and LC as well as activation of NA neurons, and that these effects of NAI might be mediated via the vagus nerves.
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Affiliation(s)
- Satoko Suzuki
- Department of Human Health Science, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
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43
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Sakamoto K, Saito T, Orman R, Koizumi K, Lazar J, Salciccioli L, Stewart M. Autonomic consequences of kainic acid-induced limbic cortical seizures in rats: Peripheral autonomic nerve activity, acute cardiovascular changes, and death. Epilepsia 2008; 49:982-96. [DOI: 10.1111/j.1528-1167.2008.01545.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lavezzi AM, Matturri L. Functional neuroanatomy of the human pre-Bötzinger complex with particular reference to sudden unexplained perinatal and infant death. Neuropathology 2008; 28:10-6. [DOI: 10.1111/j.1440-1789.2007.00824.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
The preponderance of basic obesity research focuses on its development as affected by diet and other environmental factors, genetics and their interactions. By contrast, we have been studying the reversal of a naturally-occurring seasonal obesity in Siberian hamsters. In the course of this work, we determined that the sympathetic innervation of white adipose tissue (WAT) is the principal initiator of lipid mobilization not only in these animals, but in all mammals including humans. We present irrefutable evidence for the sympathetic nervous system (SNS) innervation of WAT with respect to neuroanatomy (including its central origins as revealed by transneuronal viral tract tracers), neurochemistry (norepinephrine turnover studies) and function (surgical and chemical denervation). A relatively unappreciated role of WAT SNS innervation also is reviewed--the control of fat cell proliferation as shown by selective chemical denervation that triggers adipocyte proliferation, although the precise mechanism by which this occurs presently is unknown. There is no, however, equally strong evidence for the parasympathetic innervation of this tissue; indeed, the data largely are negative severely questioning its existence and importance. Convincing evidence also is given for the sensory innervation of WAT (as shown by tract tracing and by markers for sensory nerves in WAT), with suggestive data supporting a possible role in conveying information on the degree of adiposity to the brain. Collectively, these data offer an additional or alternative view to the predominate one of the control of body fat stores via circulating factors that serve as efferent and afferent communicators.
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Affiliation(s)
- Timothy J Bartness
- Department of Biology, Neurobiology and Behavior Program, Georgia State University, Atlanta, GA 30302-4010, USA.
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Jewell JE, Brown J, Kreeger T, Williams ES. Prion protein in cardiac muscle of elk (Cervus elaphus nelsoni) and white-tailed deer (Odocoileus virginianus) infected with chronic wasting disease. J Gen Virol 2006; 87:3443-3450. [PMID: 17030881 DOI: 10.1099/vir.0.81777-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
To investigate the possible presence of disease-associated prion protein (PrP(d)) in striated muscle of chronic wasting disease (CWD)-affected cervids, samples of diaphragm, tongue, heart and three appendicular skeletal muscles from mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus nelsoni) and moose (Alces alces shirasi) were examined by ELISA, Western immunoblot and immunohistochemistry (IHC). PrP(d) was detected in samples of heart muscle from seven of 16 CWD-infected white-tailed deer, including one free-ranging deer, and in 12 of 17 CWD-infected elk, but not in any of 13 mule deer samples, nor in the single CWD-infected moose. For white-tailed deer, PrP(d) was detected by Western blot at multiple sites throughout the heart; IHC results on ventricular sections of both elk and white-tailed deer showed positive staining in cardiac myocytes, but not in conduction tissues or nerve ganglia. Levels of PrP(d) in cardiac tissues were estimated from Western blot band intensity to be lower than levels found in brain tissue. PrP(d) was not detected in diaphragm, triceps brachii, semitendinosus, latissiumus dorsi or tongue muscles for any of the study subjects. This is the first report of PrP(d) in cardiac tissue from transmissible spongiform encephalopathy-infected ruminants in the human food chain and the first demonstration by immunological assays of PrP(d) in any striated muscle of CWD-infected cervids.
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Affiliation(s)
- Jean E Jewell
- Department of Veterinary Sciences, University of Wyoming, Wyoming State Veterinary Laboratory (WSVL), 1174 Snowy Range Road, Laramie, WY 82070, USA
| | - Jeremy Brown
- Department of Veterinary Sciences, University of Wyoming, Wyoming State Veterinary Laboratory (WSVL), 1174 Snowy Range Road, Laramie, WY 82070, USA
| | - Terry Kreeger
- Veterinary Services Branch, Wyoming Game and Fish Department (WGFD), Wheatland, WY 82201, USA
| | - Elizabeth S Williams
- Department of Veterinary Sciences, University of Wyoming, Wyoming State Veterinary Laboratory (WSVL), 1174 Snowy Range Road, Laramie, WY 82070, USA
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Fletcher J, Moody WE, Chowdhary S, Coote JH. NO-cGMP pathway at ventrolateral medullary cardiac inhibitory sites enhances the baroreceptor reflex bradycardia in the rat. Brain Res 2006; 1123:125-34. [PMID: 17064669 DOI: 10.1016/j.brainres.2006.09.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 08/29/2006] [Accepted: 09/08/2006] [Indexed: 02/02/2023]
Abstract
The neuronal isoform of the enzyme nitric oxide synthase (nNOS) has been identified in the caudal ventrolateral medulla of the rat close to the location of cardiac vagal motoneurones. Therefore in this study we tested identified ventral medulla cardioinhibitory sites for the involvement of nitric oxide (NO) in the baroreceptor-heart rate reflex pathway. In rats anaesthetised with a mixture of urethane (650 mg kg(-1)) and chloralose (50 mg kg(-1)) i.v., blood pressure and heart rate were monitored continuously and using stereotaxic coordinates the ventrolateral caudal brainstem within and around the nucleus ambiguus was systematically explored for sites producing a bradycardia of >50 bpm, without a change in blood pressure, using D,L homocysteic acid (DLH, 0.2 M) microinjections (50 nl) from a glass micropipette. Identified sites were marked with pontamine sky blue. Microinjection of the NO donor sodium nitroprusside (SNP, 1 mM, 50 nl) at a cardioinhibitory site also produced a significant bradycardia (68+/-14 bpm) while the NOS inhibitor N(G)-nitro-l-arginine (l-NNA) (3 mM, 50 nl) caused a small significant increase in heart rate (5+/-1 bpm). Baroreceptor reflex gain measured by the response in heart rate to a change in blood pressure induced by phenylephrine i.v. was significantly increased (610+/-171%, p<0.05) during the steady state of the response to SNP, whereas it was significantly reduced (73+/-5%, p<0.01) by l-NNA injection at a medullary cardioinhibitory site. An inhibitor of soluble guanylyl cyclase, (1)H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ, 1 mM, 50 nl) also significantly reduced the baroreceptor reflex gain (63+/-8%, p<0.05). The results suggest that a NOS-cGMP signalling system in the baroreceptor reflex pathway distal to the NTS and closer to cardiac vagal motoneurones in the caudal ventral medulla contributes to enhancement of cardiac vagal tone.
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Affiliation(s)
- Janine Fletcher
- Department of Physiology, The Medical School, The University of Birmingham, Birmingham B15 2TT, UK.
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Xiao YF, TenBroek EM, Wilhelm JJ, Iaizzo PA, Sigg DC. Electrophysiological characterization of murine HL-5 atrial cardiomyocytes. Am J Physiol Cell Physiol 2006; 291:C407-16. [PMID: 16571870 DOI: 10.1152/ajpcell.00020.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
HL-5 cells are cultured murine atrial cardiomyocytes and have been used in studies to address important cellular and molecular questions. However, electrophysiological features of HL-5 cells have not been characterized. In this study, we examined such properties using whole cell patch-clamp techniques. Membrane capacitance of the HL-5 cells was from 8 to 62 pF. The resting membrane potential was −57.8 ± 1.4 mV ( n = 51). Intracellular injection of depolarizing currents evoked action potentials (APs) with variable morphologies in 71% of the patched cells. Interestingly, the incidence of successful, current-induced APs positively correlated with the hyperpolarizing degrees of resting membrane potentials ( r = 0.99, P < 0.001). Only a few of the patched cells (4 of 51, 7.8%) exhibited spontaneous APs. The muscarinic agonist carbachol activated the acetylcholine-activated K+ current and significantly shortened the duration of APs. Immunostaining confirmed the presence of the muscarinic receptor type 2 in HL-5 cells. The hyperpolarization-activated cation current ( If) was detected in 39% of the patched cells. The voltage to activate 50% of If channels was −73.4 ± 1.2 mV ( n = 12). Voltage-gated Na+, Ca2+, and K+ currents were observed in the HL-5 cells with variable incidences. Compared with the adult mouse cardiomyocytes, the HL-5 cells had prolonged APs and small outward K+ currents. Our data indicate that HL-5 cells display significant electrophysiological heterogeneity of morphological appearance of APs and expression of functional ion channels. Compared with adult murine cardiomyocytes, HL-5 cells show an immature phenotype of cardiac AP morphology.
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Affiliation(s)
- Yong-Fu Xiao
- Cardiac Rhythm Disease Management, Medtronic Inc., 7000 Central Avenue NE, B252, Minneapolis, MN 55432-3576, USA.
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Wang J, Chen Y, Li K, Hou L. Blockade of inhibitory neurotransmission evoked seizure-like firing of cardiac parasympathetic neurons in brainstem slices of newborn rats: Implications for sudden deaths in patients of epilepsy. Epilepsy Res 2006; 70:172-83. [PMID: 16759837 DOI: 10.1016/j.eplepsyres.2006.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 04/25/2006] [Accepted: 04/27/2006] [Indexed: 10/24/2022]
Abstract
In patients of epilepsy a proportion of unexplained sudden deaths had been attributed to neurogenic arrhythmias. Although some evidence has suggested that epileptogenic activation of the cardiac parasympathetic nerves, which is revealed by ictal bradyarrhythmias or cardiac asystole, might be very critical in causing sudden deaths of patients of epilepsy the firing behavior of cardiac parasympathetic neurons (CPNs) during epileptic attack is not known. In the present study fluorescent tracer was injected into the cardiac sac of newborn rats to retrogradely label the parasympathetic neurons in the nucleus ambiguus (NA). The fluorescence-labeled NA neurons were further examined using whole-cell patch-clamp method in medulla slices with respiratory-like rhythm, and those with an inspiratory-related increase of the mixed inhibitory synaptic activity were identified as CPNs. We have demonstrated that blockade of the GABAergic and the glycinergic receptors in medulla slices evoked intermittent seizure-like firing of CPNs under current-clamp configuration, and evoked intermittent excitatory inward currents (IEICs) under voltage-clamp configuration. These results have given new evidence that CPNs might fire in a seizure-like pattern during epileptic attack, which might be responsible for the neurogenic ictal bradyarrhythmias, cardiac asystole, or even the sudden deaths of patients of epilepsy.
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Affiliation(s)
- Jijiang Wang
- The State Key Laboratory of Medical Neurobiology, Fudan University Shanghai Medical College, Shanghai, China.
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Trotter RN, Stornetta RL, Guyenet PG, Roberts MR. Transneuronal mapping of the CNS network controlling sympathetic outflow to the rat thymus. Auton Neurosci 2006; 131:9-20. [PMID: 16843070 DOI: 10.1016/j.autneu.2006.06.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 05/30/2006] [Accepted: 06/02/2006] [Indexed: 11/24/2022]
Abstract
The thymus is a primary immune organ that is essential for the development of functional T cells. The thymus receives sympathetic innervation, and thymocytes and thymic epithelial cells express functional adrenergic receptors. In this study, we employed retrograde, transneuronal virus tracing to identify the CNS cell groups that regulate sympathetic outflow to the thymus. Pseudorabies virus (PRV) was injected into the thymus, and the pattern of PRV infection in sympathetic regulatory centers of the CNS was determined at 72 and 120 h post-inoculation. PRV infection within the CNS first appeared within the spinal cord at 72 h post-inoculation and was confined to neurons within the intermediolateral cell column at levels T1-T7. At 120 h post-inoculation infection had spread within the spinal cord to include the central autonomic nucleus, intercalated cell nucleus and light infection within the cells of the lateral funiculus. Within the brain, PRV positive cells were found within nuclei of the medulla oblongata, pons and hypothalamus. Infection in the hypothalamus was observed within the arcuate nucleus, dorsal, lateral, and posterior hypothalamus and in all parvicellular subdivisions of the paraventricular hypothalamic nucleus. None of the infected animals exhibited labeling of the dorsal motor nucleus of the vagus. In summary, this study provides the first anatomic map of CNS neurons involved in control of sympathetic outflow to the thymus.
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Affiliation(s)
- R Nicholas Trotter
- Department of Microbiology, University of Virginia, PO Box 800734, Charlottesville, VA 22908, USA
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