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Cui K, Xia Y, Patnaik A, Salivara A, Lowenstein ED, Isik EG, Knorz AL, Airaghi L, Crotti M, Garratt AN, Meng F, Schmitz D, Studer M, Rijli FM, Nothwang HG, Rost BR, Strauß U, Hernandez-Miranda LR. Genetic identification of medullary neurons underlying congenital hypoventilation. SCIENCE ADVANCES 2024; 10:eadj0720. [PMID: 38896627 PMCID: PMC11186509 DOI: 10.1126/sciadv.adj0720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 05/14/2024] [Indexed: 06/21/2024]
Abstract
Mutations in the transcription factors encoded by PHOX2B or LBX1 correlate with congenital central hypoventilation disorders. These conditions are typically characterized by pronounced hypoventilation, central apnea, and diminished chemoreflexes, particularly to abnormally high levels of arterial PCO2. The dysfunctional neurons causing these respiratory disorders are largely unknown. Here, we show that distinct, and previously undescribed, sets of medullary neurons coexpressing both transcription factors (dB2 neurons) account for specific respiratory functions and phenotypes seen in congenital hypoventilation. By combining intersectional chemogenetics, intersectional labeling, lineage tracing, and conditional mutagenesis, we uncovered subgroups of dB2 neurons with key functions in (i) respiratory tidal volumes, (ii) the hypercarbic reflex, (iii) neonatal respiratory stability, and (iv) neonatal survival. These data provide functional evidence for the critical role of distinct medullary dB2 neurons in neonatal respiratory physiology. In summary, our work identifies distinct subgroups of dB2 neurons regulating breathing homeostasis, dysfunction of which causes respiratory phenotypes associated with congenital hypoventilation.
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Affiliation(s)
- Ke Cui
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Yiling Xia
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Abhisarika Patnaik
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Aikaterini Salivara
- German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Eser G. Isik
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Adrian L. Knorz
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Laura Airaghi
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Michela Crotti
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Alistair N. Garratt
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Fanqi Meng
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dietmar Schmitz
- German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Michèle Studer
- Université Côte d'Azur (UCA), CNRS, Inserm, Institute of Biology Valrose (iBV), Nice, France
| | - Filippo M. Rijli
- Laboratory of Developmental Neuroepigenetics, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Hans G. Nothwang
- Division of Neurogenetics, Cluster of Excellence Hearing4all, Carl von Ossietzky University, Oldenburg, Germany
| | - Benjamin R. Rost
- German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ulf Strauß
- Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Luis R. Hernandez-Miranda
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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Wang L, Cheng M, Wang Y, Chen J, Xie F, Huang LH, Zhan C. Fasting-activated ventrolateral medulla neurons regulate T cell homing and suppress autoimmune disease in mice. Nat Neurosci 2024; 27:462-470. [PMID: 38182836 DOI: 10.1038/s41593-023-01543-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/01/2023] [Indexed: 01/07/2024]
Abstract
Dietary fasting markedly influences the distribution and function of immune cells and exerts potent immunosuppressive effects. However, the mechanisms through which fasting regulates immunity remain obscure. Here we report that catecholaminergic (CA) neurons in the ventrolateral medulla (VLM) are activated during fasting in mice, and we demonstrate that the activity of these CA neurons impacts the distribution of T cells and the development of autoimmune disease in an experimental autoimmune encephalomyelitis (EAE) model. Ablation of VLM CA neurons largely reversed fasting-mediated T cell redistribution. Activation of these neurons drove T cell homing to bone marrow in a CXCR4/CXCL12 axis-dependent manner, which may be mediated by a neural circuit that stimulates corticosterone secretion. Similar to fasting, the continuous activation of VLM CA neurons suppressed T cell activation, proliferation, differentiation and cytokine production in autoimmune mouse models and substantially alleviated disease symptoms. Collectively, our study demonstrates neuronal control of inflammation and T cell distribution, suggesting a neural mechanism underlying fasting-mediated immune regulation.
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Affiliation(s)
- Liang Wang
- Department of Hematology, The First Affiliated Hospital of USTC, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Hefei National Research Center for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Mingxiu Cheng
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
- National Institute of Biological Sciences, Beijing, China
| | - Yuchen Wang
- Department of Hematology, The First Affiliated Hospital of USTC, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Hefei National Research Center for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Jing Chen
- School of Sport Science, Beijing Sport University, Beijing, China
| | - Famin Xie
- School of Life Sciences, Fudan University, Shanghai, China
| | - Li-Hao Huang
- Institute of Metabolism & Integrative Biology, Fudan University, Shanghai, China
| | - Cheng Zhan
- Department of Hematology, The First Affiliated Hospital of USTC, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Hefei National Research Center for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
- National Institute of Biological Sciences, Beijing, China.
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Knapman FL, Cohen EM, Kulaga T, Lovell N, Lisowski L, McMullan S, Burke PGR, Bilston LE. Direct optogenetic activation of upper airway muscles in an acute model of upper airway hypotonia mimicking sleep onset. Sleep 2023; 46:zsad226. [PMID: 37651221 DOI: 10.1093/sleep/zsad226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/25/2023] [Indexed: 09/02/2023] Open
Abstract
STUDY OBJECTIVES Obstructive sleep apnea (OSA), where the upper airway collapses repeatedly during sleep due to inadequate dilator muscle tone, is challenging to treat as current therapies are poorly tolerated or have variable and unpredictable efficacy. We propose a novel, optogenetics-based therapy, that stimulates upper airway dilator muscle contractions in response to light. To determine the feasibility of a novel optogenetics-based OSA therapy, we developed a rodent model of human sleep-related upper airway muscle atonia. Using this model, we evaluated intralingual delivery of candidate optogenetic constructs, notably a muscle-targeted approach that will likely have a favorable safety profile. METHODS rAAV serotype 9 viral vectors expressing a channelrhodopsin-2 variant, driven by a muscle-specific or nonspecific promoter were injected into rat tongues to compare strength and specificity of opsin expression. Light-evoked electromyographic responses were recorded in an acute, rodent model of OSA. Airway dilation was captured with ultrasound. RESULTS The muscle-specific promoter produced sufficient opsin expression for light stimulation to restore and/or enhance electromyographic signals (linear mixed model, F = 140.0, p < 0.001) and induce visible tongue contraction and airway dilation. The muscle-specific promoter induced stronger (RM-ANOVA, F(1,8) = 10.0, p = 0.013) and more specific opsin expression than the nonspecific promoter in an otherwise equivalent construct. Viral DNA and RNA were robust in the tongue, but low or absent in all other tissues. CONCLUSIONS Significant functional responses to direct optogenetic muscle activation were achieved following muscle-specific promoter-driven rAAV-mediated transduction, providing proof-of-concept for an optogenetic therapy for patients with inadequate dilator muscle activity during sleep.
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Affiliation(s)
- Fiona L Knapman
- Neuroscience Research Australia, Sydney, NSW, Australia
- School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
| | | | - Tom Kulaga
- School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Nigel Lovell
- School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Leszek Lisowski
- Translational Vectorology Research Unit, Children's Medical Research Institute, Sydney, NSW, Australia
- Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine, Warsaw, Poland
| | - Simon McMullan
- Macquarie Medical School, Macquarie University, Sydney, NSW, Australia
| | - Peter G R Burke
- Neuroscience Research Australia, Sydney, NSW, Australia
- School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
- Macquarie Medical School, Macquarie University, Sydney, NSW, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, Sydney, NSW, Australia
- School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
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Pace SA, Myers B. Hindbrain Adrenergic/Noradrenergic Control of Integrated Endocrine and Autonomic Stress Responses. Endocrinology 2023; 165:bqad178. [PMID: 38015813 DOI: 10.1210/endocr/bqad178] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/07/2023] [Accepted: 11/27/2023] [Indexed: 11/30/2023]
Abstract
Hindbrain adrenergic/noradrenergic nuclei facilitate endocrine and autonomic responses to physical and psychological challenges. Neurons that synthesize adrenaline and noradrenaline target hypothalamic structures to modulate endocrine responses while descending spinal projections regulate sympathetic function. Furthermore, these neurons respond to diverse stress-related metabolic, autonomic, and psychosocial challenges. Accordingly, adrenergic and noradrenergic nuclei are integrative hubs that promote physiological adaptation to maintain homeostasis. However, the precise mechanisms through which adrenaline- and noradrenaline-synthesizing neurons sense interoceptive and exteroceptive cues to coordinate physiological responses have yet to be fully elucidated. Additionally, the regulatory role of these cells in the context of chronic stress has received limited attention. This mini-review consolidates reports from preclinical rodent studies on the organization and function of brainstem adrenaline and noradrenaline cells to provide a framework for how these nuclei coordinate endocrine and autonomic physiology. This includes identification of hindbrain adrenaline- and noradrenaline-producing cell groups and their role in stress responding through neurosecretory and autonomic engagement. Although temporally and mechanistically distinct, the endocrine and autonomic stress axes are complementary and interconnected. Therefore, the interplay between brainstem adrenergic/noradrenergic nuclei and peripheral physiological systems is necessary for integrated stress responses and organismal survival.
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Affiliation(s)
- Sebastian A Pace
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Brent Myers
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
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5
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MacMillan S, Evans AM. AMPK facilitates the hypoxic ventilatory response through non-adrenergic mechanisms at the brainstem. Pflugers Arch 2023; 475:89-99. [PMID: 35680670 PMCID: PMC9816276 DOI: 10.1007/s00424-022-02713-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/29/2022] [Indexed: 01/31/2023]
Abstract
We recently demonstrated that the hypoxic ventilatory response (HVR) is facilitated by the AMP-activated protein kinase (AMPK) in catecholaminergic neural networks that likely lie downstream of the carotid bodies within the caudal brainstem. Here, we further subcategorise the neurons involved, by cross-comparison of mice in which the genes encoding the AMPK-α1 (Prkaa1) and AMPK-α2 (Prkaa2) catalytic subunits were deleted in catecholaminergic (TH-Cre) or adrenergic (PNMT-Cre) neurons. As expected, the HVR was markedly attenuated in mice with AMPK-α1/α2 deletion in catecholaminergic neurons, but surprisingly was modestly augmented in mice with AMPK-α1/α2 deletion in adrenergic neurons when compared against a variety of controls (TH-Cre, PNMT-Cre, AMPK-α1/α2 floxed). Moreover, AMPK-α1/α2 deletion in catecholaminergic neurons precipitated marked hypoventilation and apnoea during poikilocapnic hypoxia, relative to controls, while mice with AMPK-α1/α2 deletion in adrenergic neurons entered relative hyperventilation with reduced apnoea frequency and duration. We conclude, therefore, that AMPK-dependent modulation of non-adrenergic networks may facilitate increases in ventilatory drive that shape the classical HVR, whereas AMPK-dependent modulation of adrenergic networks may provide some form of negative feedback or inhibitory input to moderate HVR, which could, for example, protect against hyperventilation-induced hypocapnia and respiratory alkalosis.
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Affiliation(s)
- Sandy MacMillan
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - A. Mark Evans
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD UK
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6
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Lynch E, Dempsey B, Saleeba C, Monteiro E, Turner A, Burke PGR, Allen AM, Dampney RAL, Hildreth CM, Cornish JL, Goodchild AK, McMullan S. Descending pathways from the superior colliculus mediating autonomic and respiratory effects associated with orienting behaviour. J Physiol 2022; 600:5311-5332. [PMID: 36271640 PMCID: PMC10107157 DOI: 10.1113/jp283789] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/14/2022] [Indexed: 01/05/2023] Open
Abstract
The ability to discriminate competing external stimuli and initiate contextually appropriate behaviours is a key brain function. Neurons in the deep superior colliculus (dSC) integrate multisensory inputs and activate descending projections to premotor pathways responsible for orienting, attention and defence, behaviours which involve adjustments to respiratory and cardiovascular parameters. However, the neural pathways that subserve the physiological components of orienting are poorly understood. We report that orienting responses to optogenetic dSC stimulation are accompanied by short-latency autonomic, respiratory and electroencephalographic effects in awake rats, closely mimicking those evoked by naturalistic alerting stimuli. Physiological responses were not accompanied by detectable aversion or fear, and persisted under urethane anaesthesia, indicating independence from emotional stress. Anterograde and trans-synaptic viral tracing identified a monosynaptic pathway that links the dSC to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA), a key hub for the coordination of orienting and locomotor behaviours. In urethane-anaesthetized animals, sympathoexcitatory and cardiovascular, but not respiratory, responses to dSC stimulation were replicated by optogenetic stimulation of the dSC-GiA terminals, suggesting a likely role for this pathway in mediating the autonomic components of dSC-mediated responses. Similarly, extracellular recordings from putative GiA sympathetic premotor neurons confirmed short-latency excitatory inputs from the dSC. This pathway represents a likely substrate for autonomic components of orienting responses that are mediated by dSC neurons and suggests a mechanism through which physiological and motor components of orienting behaviours may be integrated without the involvement of higher centres that mediate affective components of defensive responses. KEY POINTS: Neurons in the deep superior colliculus (dSC) integrate multimodal sensory signals to elicit context-dependent innate behaviours that are accompanied by stereotypical cardiovascular and respiratory activities. The pathways responsible for mediating the physiological components of colliculus-mediated orienting behaviours are unknown. We show that optogenetic dSC stimulation evokes transient orienting, respiratory and autonomic effects in awake rats which persist under urethane anaesthesia. Anterograde tracing from the dSC identified projections to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA). Stimulation of this pathway recapitulated autonomic effects evoked by stimulation of dSC neurons. Electrophysiological recordings from putative GiA sympathetic premotor neurons confirmed short latency excitatory input from dSC neurons. This disynaptic dSC-GiA-spinal sympathoexcitatory pathway may underlie autonomic adjustments to salient environmental cues independent of input from higher centres.
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Affiliation(s)
- Erin Lynch
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Bowen Dempsey
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Christine Saleeba
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Eloise Monteiro
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Anita Turner
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Peter G R Burke
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Andrew M Allen
- Department of Physiology, University of Melbourne, Victoria, Australia
| | - Roger A L Dampney
- School of Medical Sciences (Physiology), University of Sydney, Sydney, New South Wales, Australia
| | - Cara M Hildreth
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Jennifer L Cornish
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Ann K Goodchild
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Simon McMullan
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
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Toledo C, Andrade DC, Diaz-Jara E, Ortolani D, Bernal-Santander I, Schwarz KG, Ortiz FC, Marcus NJ, Oliveira LM, Takakura AC, Moreira TS, Del Rio R. Cardiorespiratory alterations following intermittent photostimulation of RVLM C1 neurons: Implications for long-term blood pressure, breathing and sleep regulation in freely moving rats. Acta Physiol (Oxf) 2022; 236:e13864. [PMID: 35959519 DOI: 10.1111/apha.13864] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 01/29/2023]
Abstract
AIM Sympathoexcitation and sleep-disordered breathing are common contributors for disease progression. Catecholaminergic neurons from the rostral ventrolateral medulla (RVLM-C1) modulate sympathetic outflow and have anatomical projections to respiratory neurons; however, the contribution of highly selective activation of RVLM-C1 neurons on long-term autonomic and breathing (dys)regulation remains to be understood. METHODS To explore this relationship, a lentiviral vector carrying the light-sensitive cation channel channelrhodopsin-2 (LVV-PRSX8-ChR2-YFP) was unilaterally injected into the RVLM of healthy rats. On the contralateral side, LVV-PRSX8-ChR2-YFP was co-injected with a specific immunotoxin (DβH-SAP) targeted to eliminate C1 neurons. RESULTS Intermittent photostimulation of RVLM-C1 in vivo, in unrestrained freely moving rats, elicited long-term facilitation of the sympathetic drive, a rise in blood pressure and sympatho-respiratory coupling. In addition, photoactivation of RVLM-C1 induced long-lasting ventilatory instability, characterized by oscillations in tidal volume and increased breathing variability, but only during non-rapid eye movement sleep. These effects were not observed when photostimulation of the RVLM was performed in the presence of DβH-SAP toxin. CONCLUSIONS The finding that intermittent activation of RVLM-C1 neurons induces autonomic and breathing dysfunction suggest that episodic stimulation of RVLM-C1 may serve as a pathological substrate for the long-term development of cardiorespiratory disorders.
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Affiliation(s)
- Camilo Toledo
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - David C Andrade
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Esteban Diaz-Jara
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Domiziana Ortolani
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ignacio Bernal-Santander
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Karla G Schwarz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernando C Ortiz
- Mechanisms of Myelin Formation and Repair Laboratory, Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad, Autónoma de Chile, Santiago, Chile
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, Iowa, USA
| | - Luiz M Oliveira
- Department of Pharmacology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
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8
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da Silva MP, Spiller PF, Paton JFR, Moraes DJA. Peripheral chemoreflex activation induces expiratory but not inspiratory excitation of C1 pre-sympathetic neurones of rats. Acta Physiol (Oxf) 2022; 235:e13853. [PMID: 35722749 DOI: 10.1111/apha.13853] [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: 03/30/2022] [Revised: 06/10/2022] [Accepted: 06/16/2022] [Indexed: 11/30/2022]
Abstract
AIMS Stimulation of peripheral chemoreceptors, as during hypoxia, increases breathing and respiratory-related sympathetic bursting. Activation of catecholaminergic C1 neurones induces sympathoexcitation, while its ablation reduces the chemoreflex sympathoexcitatory response. However, no study has determined the respiratory phase(s) in which the pre-sympathetic C1 neurones are recruited by peripheral chemoreceptor and whether C1 neurone activation affects all phases of respiratory modulation of sympathetic activity. We addressed these unknowns by testing the hypothesis that peripheral chemoreceptor activation excites pre-sympathetic C1 neurones during inspiration and expiration. METHODS Using the in situ preparation of rat, we made intracellular recordings from baroreceptive pre-sympathetic C1 neurones during peripheral chemoreflex stimulation. We optogenetically activated C1 neurones selectively and compared any respiratory-phase-related increases in sympathetic activity with that which occurs following stimulation of the peripheral chemoreflex. RESULTS Activation of peripheral chemoreceptors using cytotoxic hypoxia (potassium cyanide) increased the firing frequency of C1 neurones and both the frequency and amplitude of their excitatory post-synaptic currents during the phase of expiration only. In contrast, optogenetic stimulation of C1 neurones activates inspiratory neurones, which secondarily inhibit expiratory neurones, but produced comparable increases in sympathetic activity across all phases of respiration. CONCLUSION Our data reveal that the peripheral chemoreceptor-mediated expiratory-related sympathoexcitation is mediated through excitation of expiratory neurones antecedent to C1 pre-sympathetic neurones; these may be found in the Kölliker-Fuse nucleus. Despite peripheral chemoreceptor excitation of inspiratory neurones, these do not trigger C1 neurone-mediated increases in sympathetic activity. These studies provide compelling novel insights into the functional organization of respiratory-sympathetic neural networks.
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Affiliation(s)
- Melina P da Silva
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Pedro F Spiller
- 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
| | - Davi J A Moraes
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
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Fenik VB, Rukhadze I. Activity of Pontine A7 Noradrenergic Neurons is suppressed during REM sleep. J Appl Physiol (1985) 2022; 133:130-143. [PMID: 35616303 PMCID: PMC9255708 DOI: 10.1152/japplphysiol.00771.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The activity of hypoglossal motoneurons plays a key role in the maintenance of upper airway patency. The withdrawal of noradrenergic excitatory drive and increase of cholinergic inhibition markedly decreases excitability of hypoglossal motoneurons during sleep and especially during rapid-eye-movement (REM) stage. This leads to increased collapsibility of upper airway during sleep, which is the major neurological factor of obstructive sleep apnea (OSA) pathophysiology. Anatomical and functional data suggests that noradrenergic A7 neurons are the main source of noradrenergic drive to hypoglossal motoneurons. However, it is unknown whether the behavior of A7 neurons during sleep-wake cycle is in accord with their proposed involvement in sleep-related depression of hypoglossal motoneuron activity. Therefore, we sought to assess the behavior of A7 neurons during sleep and wakefulness in naturally sleeping head-restrained rats. We have found that, similar to other pontine noradrenergic neurons, the putative A7 noradrenergic neurons fired with relatively long-lasting action potentials with a low frequency regular discharge. Importantly, all noradrenergic A7 neurons were predominantly silent during REM sleep. The REM-off activity of the A7 neurons supports our hypothesis that these neurons may significantly contribute to the withdrawal of excitatory noradrenergic drive from upper airway motoneurons during REM sleep and, consequently, play a critical role in maintaining upper airway patency and pathophysiology of OSA. Therefore, noradrenergic A7 neurons may serve as an additional target for designing pharmacological approaches to treat OSA.
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Affiliation(s)
- Victor B Fenik
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States.,VA Greater Los Angeles Healthcare System, West Los Angeles, CA, United States
| | - Irma Rukhadze
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States.,VA Greater Los Angeles Healthcare System, West Los Angeles, CA, United States.,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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Zoccal DB. The nature of sympathetic rhythmicity. J Physiol 2022; 600:2537-2539. [DOI: 10.1113/jp282863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Daniel B. Zoccal
- Department of Physiology and Pathology School of Dentistry of Araraquara São Paulo State University
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11
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Severs L, Vlemincx E, Ramirez JM. The psychophysiology of the sigh: I: The sigh from the physiological perspective. Biol Psychol 2022; 170:108313. [DOI: 10.1016/j.biopsycho.2022.108313] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 12/30/2022]
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Wu Y, Luo Z, Hu Z, Lv K, Liu Y, Wang D. Optical Activation of the Dorsal Horn of the Thoracic Spinal Cord Prevents Ventricular Arrhythmias in Acute Myocardial Ischemia-Reperfusion Rats. Front Cardiovasc Med 2022; 9:753959. [PMID: 35198610 PMCID: PMC8858961 DOI: 10.3389/fcvm.2022.753959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 01/05/2022] [Indexed: 11/13/2022] Open
Abstract
Background and ObjectivesSpinal cord stimulation can prevent myocardial ischemia and reperfusion arrhythmias, but the relevant neurons and mechanisms remain unknown. Thus, this study applied optogenetic techniques to selectively activate glutamatergic neurons at the thoracic spinal cord (T1 segment) for examining the anti-arrhythmia effects during acute myocardial ischemic-reperfusion.MethodsAdeno-associated viruses (AAVs) carrying channelrhodopsin-2 (ChR2, a blue-light sensitive ion channel) CaMKIIα-hChR2(H134R) or empty vector were injected into the dorsal horn of the T1 spinal cord. Four weeks later, optogenetic stimulation with a 473-nm blue laser was applied for 30 min. Then, the myocardial ischemia-reperfusion model was created by occlusion of the anterior descending coronary artery for ischemia (15 min) and reperfusion (30 min). Cardiac electrical activity and sympathetic nerve activity were assessed continuously.ResultsCaMKIIα-hChR2 viral transfection is primarily expressed in glutamatergic neurons in the spinal cord. Selective optical stimulation of the T1 dorsal horn in the ChR2 rat reduced the ventricular arrhythmia and arrhythmia score during myocardial ischemia-reperfusion, preventing the over-activation of cardiac sympathetic nerve activity. Additionally, optical stimulation also reduced the action potential duration at the 90% level (APD90) and APD dispersion.ConclusionSelective optical stimulation T1 glutamatergic neurons of dorsal horn prevent ischemia-reperfusion arrhythmias. The mechanism may be associated with inhibiting sympathetic nervous system overexcitation and increasing APD dispersion during myocardial ischemia-reperfusion.
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Affiliation(s)
- Yong Wu
- Department of Gerontology, First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Zhongxu Luo
- Department of Gerontology, First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Zhengtao Hu
- Department of Gerontology, First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Kun Lv
- Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institution (Wannan Medical College), Wuhu, China
| | - Yinhua Liu
- Department of Pathology, First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Deguo Wang
- Department of Gerontology, First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
- Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institution (Wannan Medical College), Wuhu, China
- *Correspondence: Deguo Wang
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Kubin L. Breathing during sleep. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:179-199. [PMID: 35965026 DOI: 10.1016/b978-0-323-91534-2.00005-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The depth, rate, and regularity of breathing change following transition from wakefulness to sleep. Interactions between sleep and breathing involve direct effects of the central mechanisms that generate sleep states exerted at multiple respiratory regulatory sites, such as the central respiratory pattern generator, respiratory premotor pathways, and motoneurons that innervate the respiratory pump and upper airway muscles, as well as effects secondary to sleep-related changes in metabolism. This chapter discusses respiratory effects of sleep as they occur under physiologic conditions. Breathing and central respiratory neuronal activities during nonrapid eye movement (NREM) sleep and REM sleep are characterized in relation to activity of central wake-active and sleep-active neurons. Consideration is given to the obstructive sleep apnea syndrome because in this common disorder, state-dependent control of upper airway patency by upper airway muscles attains high significance and recurrent arousals from sleep are triggered by hypercapnic and hypoxic episodes. Selected clinical trials are discussed in which pharmacological interventions targeted transmission in noradrenergic, serotonergic, cholinergic, and other state-dependent pathways identified as mediators of ventilatory changes during sleep. Central pathways for arousals elicited by chemical stimulation of breathing are given special attention for their important role in sleep loss and fragmentation in sleep-related respiratory disorders.
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Affiliation(s)
- Leszek Kubin
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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14
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Abstract
Breathing is a critical, complex, and highly integrated behavior. Normal rhythmic breathing, also referred to as eupnea, is interspersed with different breathing related behaviors. Sighing is one of such behaviors, essential for maintaining effective gas exchange by preventing the gradual collapse of alveoli in the lungs, known as atelectasis. Critical for the generation of both sighing and eupneic breathing is a region of the medulla known as the preBötzinger Complex (preBötC). Efforts are underway to identify the cellular pathways that link sighing as well as sneezing, yawning, and hiccupping with other brain regions to better understand how they are integrated and regulated in the context of other behaviors including chemosensation, olfaction, and cognition. Unraveling these interactions may provide important insights into the diverse roles of these behaviors in the initiation of arousal, stimulation of vigilance, and the relay of certain behavioral states. This chapter focuses primarily on the function of the sigh, how it is locally generated within the preBötC, and what the functional implications are for a potential link between sighing and cognitive regulation. Furthermore, we discuss recent insights gained into the pathways and mechanisms that control yawning, sneezing, and hiccupping.
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NODA M, MATSUDA T. Central regulation of body fluid homeostasis. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2022; 98:283-324. [PMID: 35908954 PMCID: PMC9363595 DOI: 10.2183/pjab.98.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Extracellular fluids, including blood, lymphatic fluid, and cerebrospinal fluid, are collectively called body fluids. The Na+ concentration ([Na+]) in body fluids is maintained at 135-145 mM and is broadly conserved among terrestrial animals. Homeostatic osmoregulation by Na+ is vital for life because severe hyper- or hypotonicity elicits irreversible organ damage and lethal neurological trauma. To achieve "body fluid homeostasis" or "Na homeostasis", the brain continuously monitors [Na+] in body fluids and controls water/salt intake and water/salt excretion by the kidneys. These physiological functions are primarily regulated based on information on [Na+] and relevant circulating hormones, such as angiotensin II, aldosterone, and vasopressin. In this review, we discuss sensing mechanisms for [Na+] and hormones in the brain that control water/salt intake behaviors, together with the responsible sensors (receptors) and relevant neural pathways. We also describe mechanisms in the brain by which [Na+] increases in body fluids activate the sympathetic neural activity leading to hypertension.
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Affiliation(s)
- Masaharu NODA
- Homeostatic Mechanism Research Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
- Correspondence should be addressed to: Homeostatic Mechanism Research Unit, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama, Kanagawa 226-8503, Japan (e-mail: )
| | - Takashi MATSUDA
- Homeostatic Mechanism Research Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
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Malheiros-Lima MR, Silva TM, Takakura AC, Moreira TS. A5 noradrenergic-projecting C1 neurons activate sympathetic and breathing outputs in anaesthetized rats. Exp Physiol 2021; 107:147-160. [PMID: 34813109 DOI: 10.1113/ep089691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/16/2021] [Indexed: 12/18/2022]
Abstract
NEW FINDINGS What is the central question of this study? C1 neurons innervate pontine noradrenergic cell groups, including the A5 region: do A5 noradrenergic neurons contribute to the activation of sympathetic and respiratory responses produced by selective activation of the C1 group of neurons. What is the main finding and its importance? The increase in sympathetic and respiratory activities elicited by selective stimulation of C1 neurons is reduced after blockade of excitatory amino acid within the A5 region, suggesting that the C1-A5 pathway might be important for sympathetic-respiratory control. ABSTRACT Adrenergic C1 neurons innervate and excite pontine noradrenergic cell groups, including the ventrolateral pontine noradrenergic region (A5). Here, we tested the hypothesis that C1 activates A5 neurons through the release of glutamate and this effect is important for sympathetic and respiratory control. Using selective tools, we restricted the expression of channelrhodopsin2 under the control of the artificial promoter PRSx8 to C1 neurons (69%). Transduced catecholaminergic terminals within the A5 region are in contact with noradrenergic A5 neurons and the C1 terminals within the A5 region are predominantly glutamatergic. In a different group of animals, we performed retrograde lesion of C1 adrenergic neurons projecting to the A5 region with unilateral injection of the immunotoxin anti-dopamine β-hydroxylase-saporin (anti-DβH-SAP) directly into the A5 region during the hypoxic condition. As expected, hypoxia (8% O2 , 3 h) induced a robust increase in fos expression within the catecholaminergic C1 and A5 regions of the brainstem. Depletion of C1 cells projecting to the A5 regions reduced fos immunoreactivity induced by hypoxia within the C1 region. Physiological experiments showed that bilateral injection of kynurenic acid (100 mM) into the A5 region reduced the rise in mean arterial pressure, and sympathetic and phrenic nerve activities produced by optogenetic stimulation of C1 cells. In conclusion, the C1 neurons activate the ventrolateral pontine noradrenergic neurons (A5 region) possibly via the release of glutamate and might be important for sympathetic and respiratory outputs in anaesthetized rats.
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Affiliation(s)
- Milene R Malheiros-Lima
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
| | - Talita M Silva
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, SP, Brazil
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Oliveira LM, Takakura AC, Moreira TS. Forebrain and Hindbrain Projecting-neurons Target the Post-inspiratory Complex Cholinergic Neurons. Neuroscience 2021; 476:102-115. [PMID: 34582982 DOI: 10.1016/j.neuroscience.2021.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/19/2021] [Accepted: 09/20/2021] [Indexed: 02/06/2023]
Abstract
The postinspiratory complex (PiCo) is a region located in the ventromedial medulla involved with the post-inspiratory activity. PiCo neurons are excitatory (VGlut2+) and express the enzyme choline acetyl transferase (ChAT+). Evidence also suggests that PiCo is coupled to two additional groups of neurons involved in breathing process, i.e. the pre-Bötzinger complex (preBötC, inspiration) and the retrotrapezoid nucleus (RTN, active expiration), composing all together, the hypothesized triple respiratory oscillator. Here, our main objective is to demonstrate the afferent connections to PiCo region. We mapped projecting-neurons to PiCo by injecting Fluorogold (FG) retrograde tracer into the PiCo of adult Long-Evans Chat-cre male rats. We reported extensive projections from periaqueductal grey matter and Kölliker-Fuse regions and mild projections from the nucleus of the solitary tract, ventrolateral medulla and hypothalamus. We also injected a cre-dependent vector expressing channelrhodopsin 2 (AAV5-ChR2) fused with enhanced mCherry into the PiCo of ChAT-cre rats to optogenetic activate those neurons and investigate the role of PiCo for inspiratory/postinspiratory activity. Both in urethane-anesthetized and unrestrained conscious rats the response of ChR2-transduced neurons to light induced an increase in postinspiratory activity. Our data confirmed that PiCo seems to be dedicated to postinspiratory activity and represent a site of integration for autonomic and motor components of respiratory and non-respiratory pathways.
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Affiliation(s)
- Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000 Sao Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000 Sao Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000 Sao Paulo, SP, Brazil.
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Abstract
We have discovered that the ventrolateral medulla (VLM) catecholaminergic (CA) neurons, a group of neurons that control mouse stress response, are activated in tumor-bearing mice, and the neuronal activity promotes tumor growth in multiple syngeneic and spontaneous mouse tumor models. The tumor-promoting effect of these VLM CA neurons is mediated by cytotoxic T cells. These findings establish an interaction between a tumor and a group of neurons in the mouse brain that influences tumorigenesis and tumor growth by modulating adaptive immunity. It is known that tumor growth can be influenced by the nervous system. It is not known, however, if tumors communicate directly with the central nervous system (CNS) or if such interactions may impact tumor growth. Here, we report that ventrolateral medulla (VLM) catecholaminergic (CA) neurons in the mouse brain are activated in tumor-bearing mice and the activity of these neurons significantly alter tumor growth in multiple syngeneic and spontaneous mouse tumor models. Specific ablation of VLM CA neurons by a dopamine-β-hydroxylase (DBH) promotor-activated apoptosis-promoting caspase-3 in Dbh-Cre mice as well as inhibition of these neurons by a chemogenetic method slowed tumor progression. Consistently, chemogenetic activation of VLM CA neurons promoted tumor growth. The tumor inhibition effect of VLM CA neuron ablation is mitigated in Dbh-Cre;Rag1−/− mice, indicating that this regulatory effect is mediated by the adaptive immune system. Specific depletion of CD8+ T cells using an anti-CD8+ antibody also mitigated the tumor suppression resulting from the VLM CA neuron ablation. Finally, we showed that the VLM CA neuronal ablation had an additive antitumor effect with paclitaxel treatment. Collectively, our study uncovered the role of VLM CA neurons in the mouse brain in controlling tumor growth in the mouse body.
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Girin B, Juventin M, Garcia S, Lefèvre L, Amat C, Fourcaud-Trocmé N, Buonviso N. The deep and slow breathing characterizing rest favors brain respiratory-drive. Sci Rep 2021; 11:7044. [PMID: 33782487 PMCID: PMC8007577 DOI: 10.1038/s41598-021-86525-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 03/15/2021] [Indexed: 12/15/2022] Open
Abstract
A respiration-locked activity in the olfactory brain, mainly originating in the mechano-sensitivity of olfactory sensory neurons to air pressure, propagates from the olfactory bulb to the rest of the brain. Interestingly, changes in nasal airflow rate result in reorganization of olfactory bulb response. By leveraging spontaneous variations of respiratory dynamics during natural conditions, we investigated whether respiratory drive also varies with nasal airflow movements. We analyzed local field potential activity relative to respiratory signal in various brain regions during waking and sleep states. We found that respiration regime was state-specific, and that quiet waking was the only vigilance state during which all the recorded structures can be respiration-driven whatever the respiratory frequency. Using CO2-enriched air to alter respiratory regime associated to each state and a respiratory cycle based analysis, we evidenced that the large and strong brain drive observed during quiet waking was related to an optimal trade-off between depth and duration of inspiration in the respiratory pattern, characterizing this specific state. These results show for the first time that changes in respiration regime affect cortical dynamics and that the respiratory regime associated with rest is optimal for respiration to drive the brain.
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Affiliation(s)
- Baptiste Girin
- Lyon Neuroscience Research Center (CRNL), Inserm U 1028, CNRS UMR 5292, University Lyon 1, 69675, Bron, France
| | - Maxime Juventin
- Lyon Neuroscience Research Center (CRNL), Inserm U 1028, CNRS UMR 5292, University Lyon 1, 69675, Bron, France
| | - Samuel Garcia
- Lyon Neuroscience Research Center (CRNL), Inserm U 1028, CNRS UMR 5292, University Lyon 1, 69675, Bron, France
| | - Laura Lefèvre
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, UK
| | - Corine Amat
- Lyon Neuroscience Research Center (CRNL), Inserm U 1028, CNRS UMR 5292, University Lyon 1, 69675, Bron, France
| | - Nicolas Fourcaud-Trocmé
- Lyon Neuroscience Research Center (CRNL), Inserm U 1028, CNRS UMR 5292, University Lyon 1, 69675, Bron, France
| | - Nathalie Buonviso
- Lyon Neuroscience Research Center (CRNL), Inserm U 1028, CNRS UMR 5292, University Lyon 1, 69675, Bron, France.
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20
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Schmeichel AM, Coon EA, Parisi JE, Singer W, Low PA, Benarroch EE. Loss of putative GABAergic neurons in the ventrolateral medulla in multiple system atrophy. Sleep 2021; 44:6182442. [PMID: 33755181 DOI: 10.1093/sleep/zsab074] [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: 12/08/2020] [Revised: 03/17/2021] [Indexed: 11/12/2022] Open
Abstract
STUDY OBJECTIVES Multiple system atrophy (MSA) is associated with disturbances in cardiovascular, sleep and respiratory control. The lateral paragigantocellular nucleus (LPGi) in the ventrolateral medulla (VLM) contains GABAergic neurons that participate in control of rapid eye movement (REM) sleep and cardiovagal responses. We sought to determine whether there was loss of putative GABAergic neurons in the LPGi and adjacent regions in MSA. METHODS Sections of the medulla were processed for GAD65/67 immunoreactivity in eight subjects with clinical and neuropathological diagnosis of MSA and in six control subjects. These putative GABAergic LPGi neurons were mapped based on their relationship to adjacent monoaminergic VLM groups. RESULTS There were markedly decreased numbers of GAD-immunoreactive neurons in the LPGi and adjacent VLM regions in MSA. CONCLUSIONS There is loss of GABAergic neurons in the VLM, including the LPGi in patients with MSA. Whereas these findings provide a possible mechanistic substrate, given the few cases included, further studies are necessary to determine whether they contribute to REM sleep-related cardiovagal and possibly respiratory dysregulation in MSA.
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Affiliation(s)
| | | | - Joseph E Parisi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | | | - Phillip A Low
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
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21
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Differential Contribution of the Retrotrapezoid Nucleus and C1 Neurons to Active Expiration and Arousal in Rats. J Neurosci 2020; 40:8683-8697. [PMID: 32973046 DOI: 10.1523/jneurosci.1006-20.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/13/2020] [Accepted: 09/14/2020] [Indexed: 12/31/2022] Open
Abstract
Collectively, the retrotrapezoid nucleus (RTN) and adjacent C1 neurons regulate breathing, circulation and the state of vigilance, but previous methods to manipulate the activity of these neurons have been insufficiently selective to parse out their relative roles. We hypothesize that RTN and C1 neurons regulate distinct aspects of breathing (e.g., frequency, amplitude, active expiration, sighing) and differ in their ability to produce arousal from sleep. Here we use optogenetics and a combination of viral vectors in adult male and female Th-Cre rats to transduce selectively RTN (Phox2b+ /Nmb +) or C1 neurons (Phox2b+/Th +) with Channelrhodopsin-2. RTN photostimulation modestly increased the probability of arousal. RTN stimulation robustly increased breathing frequency and amplitude; it also triggered strong active expiration but not sighs. Consistent with these responses, RTN innervates the entire pontomedullary respiratory network, including expiratory premotor neurons in the caudal ventral respiratory group, but RTN has very limited projections to brainstem regions that regulate arousal (locus ceruleus, CGRP+ parabrachial neurons). C1 neuron stimulation produced robust arousals and similar increases in breathing frequency and amplitude compared with RTN stimulation, but sighs were elicited and active expiration was absent. Unlike RTN, C1 neurons innervate the locus ceruleus, CGRP+ processes within the parabrachial complex, and lack projections to caudal ventral respiratory group. In sum, stimulating C1 or RTN activates breathing robustly, but only RTN neuron stimulation produces active expiration, consistent with their role as central respiratory chemoreceptors. Conversely, C1 stimulation strongly stimulates ascending arousal systems and sighs, consistent with their postulated role in acute stress responses.SIGNIFICANCE STATEMENT The C1 neurons and the retrotrapezoid nucleus (RTN) reside in the rostral ventrolateral medulla. Both regulate breathing and the cardiovascular system but in ways that are unclear because of technical limitations (anesthesia, nonselective neuronal actuators). Using optogenetics in unanesthetized rats, we found that selective stimulation of either RTN or C1 neurons activates breathing. However, only RTN triggers active expiration, presumably because RTN, unlike C1, has direct excitatory projections to abdominal premotor neurons. The arousal potential of the C1 neurons is far greater than that of the RTN, however, consistent with C1's projections to brainstem wake-promoting structures. In short, C1 neurons orchestrate cardiorespiratory and arousal responses to somatic stresses, whereas RTN selectively controls lung ventilation and arterial Pco2 stability.
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22
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Su CK. State-dependent modulation of sympathetic firing by α 1-adrenoceptors requires constitutive PKC activity in the neonatal rat spinal cord. Auton Neurosci 2020; 227:102688. [PMID: 32502943 DOI: 10.1016/j.autneu.2020.102688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/10/2020] [Accepted: 05/15/2020] [Indexed: 01/02/2023]
Abstract
The central adrenergic and noradrenergic neurotransmitter systems diffusively affect the operation of the spinal neural network and dynamically gauge central sympathetic outflow. Using in vitro splanchnic nerve-thoracic spinal cord preparations as an experimental model, this study examined the intraspinal α1-adrenoceptor-meidated modulation of sympathetic firing behaviors. Several sympathetic single-fiber activities were simultaneously recorded. Application of phenylephrine (Phe, an α1-adrenoceptor agonist) increased, decreased or did not affect spontaneous firing. A log-log plot of the change ratios of the average firing rates (AFR) versus their basal AFR displays a linear data distribution. Thus, the heterogeneity in α1-adrenoceptor-mediated responses is well described by a power law function. Phe-induced power-law firing modulation (plFM) was sensitive to prazosin (Prz, an α1-adrenoceptor antagonist). Heparin (Hep, a competitive IP3 receptor blocker) and chelerythrine (Che, a protein kinase C inhibitor) also caused plFM. Phe-induced plFM persisted in the presence of Hep; however, it was occluded by Che pretreatment. Pair-wise analysis of single-fiber activities revealed synchronous sympathetic discharges. Application of Phe, Hep or Che suppressed synchronous discharges in fiber pairs with apparent correlated firing (ACF) and induced or potentiated synchronous discharges in those without or with minimal ACF. Thus, the basal activities of the sympathetic preganglionic neurons participate in determining the responses mediated by the activation of α1-adrenoceptors. This deterministic factor, which is intrinsic to spinal neural networks, helps the supraspinal adrenergic and noradrenergic systems differentially control their widely distributed neural targets.
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Affiliation(s)
- Chun-Kuei Su
- Department of Biotechnology, College of Life Science, Zhaoqing University, Zhaoqing, Guangdong, China; Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC.
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23
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De-Giorgio F, Bilel S, Tirri M, Arfè R, Trapella C, Camuto C, Foti F, Frisoni P, Neri M, Botrè F, Marti M. Methiopropamine and its acute behavioral effects in mice: is there a gray zone in new psychoactive substances users? Int J Legal Med 2020; 134:1695-1711. [DOI: 10.1007/s00414-020-02302-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/14/2020] [Indexed: 12/18/2022]
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Malheiros-Lima MR, Silva JN, Souza FC, Takakura AC, Moreira TS. C1 neurons are part of the circuitry that recruits active expiration in response to the activation of peripheral chemoreceptors. eLife 2020; 9:52572. [PMID: 31971507 PMCID: PMC7010411 DOI: 10.7554/elife.52572] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/21/2020] [Indexed: 12/18/2022] Open
Abstract
Breathing results from the interaction of two distinct oscillators: the pre-Bötzinger Complex (preBötC), which drives inspiration; and the lateral parafacial region (pFRG), which drives active expiration. The pFRG is silent at rest and becomes rhythmically active during the stimulation of peripheral chemoreceptors, which also activates adrenergic C1 cells. We postulated that the C1 cells and the pFRG may constitute functionally distinct but interacting populations for controlling expiratory activity during hypoxia. We found in rats that: a) C1 neurons are activated by hypoxia and project to the pFRG region; b) active expiration elicited by hypoxia was blunted after blockade of ionotropic glutamatergic receptors at the level of the pFRG; and c) selective depletion of C1 neurons eliminated the active expiration elicited by hypoxia. These results suggest that C1 cells may regulate the respiratory cycle, including active expiration, under hypoxic conditions.
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Affiliation(s)
- Milene R Malheiros-Lima
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Josiane N Silva
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Felipe C Souza
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
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25
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Debi RA, Spector SP. Heart to breathe: partial ablation of rostral ventrolateral medulla catecholaminergic neurons mediates disordered breathing in volume overload heart failure rats. J Physiol 2020; 598:447-449. [PMID: 31900936 DOI: 10.1113/jp279368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Ryan Andrew Debi
- York University, Biology, 4700 Keele St., Toronto, Ontario, M3J 1P3, Canada
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Souza GMPR, Stornetta RL, Stornetta DS, Abbott SBG, Guyenet PG. Contribution of the Retrotrapezoid Nucleus and Carotid Bodies to Hypercapnia- and Hypoxia-induced Arousal from Sleep. J Neurosci 2019; 39:9725-9737. [PMID: 31641048 PMCID: PMC6891059 DOI: 10.1523/jneurosci.1268-19.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/03/2019] [Accepted: 10/16/2019] [Indexed: 11/21/2022] Open
Abstract
The combination of hypoxia and hypercapnia during sleep produces arousal, which helps restore breathing and normalizes blood gases. Hypercapnia and hypoxia produce arousal in mammals by activating central (pH-sensitive) and peripheral (primarily O2-sensitive) chemoreceptors. The relevant chemoreceptors and the neuronal circuits responsible for arousal are largely unknown. Here we examined the contribution of two lower brainstem nuclei that could be implicated in CO2 and hypoxia-induced arousal: the retrotrapezoid nucleus (RTN), a CO2-responsive nucleus, which mediates the central respiratory chemoreflex; and the C1 neurons, which are hypoxia activated and produce arousal and blood pressure increases when directly stimulated. Additionally, we assessed the contribution of the carotid bodies (CBs), the main peripheral chemoreceptors in mammals, to hypoxia and CO2-induced arousal. In unanesthetized male rats, we tested whether ablation of the RTN, CBs, or C1 neurons affects arousal from sleep and respiratory responses to hypercapnia or hypoxia. The sleep-wake pattern was monitored by EEG and neck EMG recordings and breathing by whole-body plethysmography. The latency to arousal in response to hypoxia or hypercapnia was determined along with changes in ventilation coincident with the arousal. RTN lesions impaired CO2-induced arousal but had no effect on hypoxia-induced arousal. CB ablation impaired arousal to hypoxia and, to a lesser extent, hypercapnia. C1 neuron ablation had no effect on arousal. Thus, the RTN contributes to CO2-induced arousal, whereas the CBs contribute to both hypoxia and CO2-induced arousal. Asphyxia-induced arousal likely requires the combined activation of RTN, CBs and other central chemoreceptors.SIGNIFICANCE STATEMENT Hypercapnia and hypoxia during sleep elicit arousal, which facilitates airway clearing in the case of obstruction and reinstates normal breathing in the case of hypoventilation or apnea. Arousal can also be detrimental to health by interrupting sleep. We sought to clarify how CO2 and hypoxia cause arousal. We show that the retrotrapezoid nucleus, a brainstem nucleus that mediates the effect of brain acidification on breathing, also contributes to arousal elicited by CO2 but not hypoxia. We also show that the carotid bodies contribute predominantly to hypoxia-induced arousal. Lesions of the retrotrapezoid nucleus or carotid bodies attenuate, but do not eliminate, arousal to CO2 or hypoxia; therefore, we conclude that these structures are not the sole trigger of CO2 or hypoxia-induced arousal.
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Affiliation(s)
- George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
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Toledo C, Andrade DC, Díaz HS, Pereyra KV, Schwarz KG, Díaz-Jara E, Oliveira LM, Takakura AC, Moreira TS, Schultz HD, Marcus NJ, Del Rio R. Rostral ventrolateral medullary catecholaminergic neurones mediate irregular breathing pattern in volume overload heart failure rats. J Physiol 2019; 597:5799-5820. [PMID: 31642520 DOI: 10.1113/jp278845] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/14/2019] [Indexed: 08/25/2023] Open
Abstract
KEY POINTS A strong association between disordered breathing patterns, elevated sympathetic activity, and enhanced central chemoreflex drive has been shown in experimental and human heart failure (HF). The aim of this study was to determine the contribution of catecholaminergic rostral ventrolateral medulla catecholaminergic neurones (RVLM-C1) to both haemodynamic and respiratory alterations in HF. Apnoea/hypopnoea incidence (AHI), breathing variability, respiratory-cardiovascular coupling, cardiac autonomic control and cardiac function were analysed in HF rats with or without selective ablation of RVLM-C1 neurones. Partial lesion (∼65%) of RVLM-C1 neurones reduces AHI, respiratory variability, and respiratory-cardiovascular coupling in HF rats. In addition, the deleterious effects of central chemoreflex activation on cardiac autonomic balance and cardiac function in HF rats was abolished by ablation of RVLM-C1 neurones. Our findings suggest that RVLM-C1 neurones play a pivotal role in breathing irregularities in volume overload HF, and mediate the sympathetic responses induced by acute central chemoreflex activation. ABSTRACT Rostral ventrolateral medulla catecholaminergic neurones (RVLM-C1) modulate sympathetic outflow and breathing under normal conditions. Heart failure (HF) is characterized by chronic RVLM-C1 activation, increased sympathetic activity and irregular breathing patterns. Despite studies showing a relationship between RVLM-C1 and sympathetic activity in HF, no studies have addressed a potential contribution of RVLM-C1 neurones to irregular breathing in this context. Thus, the aim of this study was to determine the contribution of RVLM-C1 neurones to irregular breathing patterns in HF. Sprague-Dawley rats underwent surgery to induce volume overload HF. Anti-dopamine β-hydroxylase-saporin toxin (DβH-SAP) was used to selectively lesion RVLM-C1 neurones. At 8 weeks post-HF induction, breathing pattern, blood pressures (BP), respiratory-cardiovascular coupling (RCC), central chemoreflex function, cardiac autonomic control and cardiac function were studied. Reduction (∼65%) of RVLM-C1 neurones resulted in attenuation of irregular breathing, decreased apnoea-hypopnoea incidence (11.1 ± 2.9 vs. 6.5 ± 2.5 events h-1 ; HF+Veh vs. HF+DβH-SAP; P < 0.05) and improved cardiac autonomic control in HF rats. Pathological RCC was observed in HF rats (peak coherence >0.5 between breathing and cardiovascular signals) and was attenuated by DβH-SAP treatment (coherence: 0.74 ± 0.12 vs. 0.54 ± 0.10, HF+Veh vs. HF+DβH-SAP rats; P < 0.05). Central chemoreflex activation had deleterious effects on cardiac function and cardiac autonomic control in HF rats that were abolished by lesion of RVLM-C1 neurones. Our findings reveal that RVLM-C1 neurones play a major role in irregular breathing patterns observed in volume overload HF and highlight their contribution to cardiac dysautonomia and deterioration of cardiac function during chemoreflex activation.
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Affiliation(s)
- Camilo Toledo
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - David C Andrade
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación en Fisiología del Ejercicio, Universidad Mayor, Santiago, Chile
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Katherin V Pereyra
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Karla G Schwarz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Esteban Díaz-Jara
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luiz M Oliveira
- Department of Pharmacology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA, USA
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
- Centro de Envejecimiento y Regeneración (CARE-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
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Souza GMPR, Kanbar R, Stornetta DS, Abbott SBG, Stornetta RL, Guyenet PG. Breathing regulation and blood gas homeostasis after near complete lesions of the retrotrapezoid nucleus in adult rats. J Physiol 2019; 596:2521-2545. [PMID: 29667182 DOI: 10.1113/jp275866] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/04/2018] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS The retrotrapezoid nucleus (RTN) drives breathing proportionally to brain PCO2 but its role during various states of vigilance needs clarification. Under normoxia, RTN lesions increased the arterial PCO2 set-point, lowered the PO2 set-point and reduced alveolar ventilation relative to CO2 production. Tidal volume was reduced and breathing frequency increased to a comparable degree during wake, slow-wave sleep and REM sleep. RTN lesions did not produce apnoeas or disordered breathing during sleep. RTN lesions in rats virtually eliminated the central respiratory chemoreflex (CRC) while preserving the cardiorespiratory responses to hypoxia; the relationship between CRC and number of surviving RTN Nmb neurons was an inverse exponential. The CRC does not function without the RTN. In the quasi-complete absence of the RTN and CRC, alveolar ventilation is reduced despite an increased drive to breathe from the carotid bodies. ABSTRACT The retrotrapezoid nucleus (RTN) is one of several CNS nuclei that contribute, in various capacities (e.g. CO2 detection, neuronal modulation) to the central respiratory chemoreflex (CRC). Here we test how important the RTN is to PCO2 homeostasis and breathing during sleep or wake. RTN Nmb-positive neurons were killed with targeted microinjections of substance P-saporin conjugate in adult rats. Under normoxia, rats with large RTN lesions (92 ± 4% cell loss) had normal blood pressure and arterial pH but were hypoxic (-8 mmHg PaO2 ) and hypercapnic (+10 mmHg ). In resting conditions, minute volume (VE ) was normal but breathing frequency (fR ) was elevated and tidal volume (VT ) reduced. Resting O2 consumption and CO2 production were normal. The hypercapnic ventilatory reflex in 65% FiO2 had an inverse exponential relationship with the number of surviving RTN neurons and was decreased by up to 92%. The hypoxic ventilatory reflex (HVR; FiO2 21-10%) persisted after RTN lesions, hypoxia-induced sighing was normal and hypoxia-induced hypotension was reduced. In rats with RTN lesions, breathing was lowest during slow-wave sleep, especially under hyperoxia, but apnoeas and sleep-disordered breathing were not observed. In conclusion, near complete RTN destruction in rats virtually eliminates the CRC but the HVR persists and sighing and the state dependence of breathing are unchanged. Under normoxia, RTN lesions cause no change in VE but alveolar ventilation is reduced by at least 21%, probably because of increased physiological dead volume. RTN lesions do not cause sleep apnoea during slow-wave sleep, even under hyperoxia.
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Affiliation(s)
- George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
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Optogenetic analysis of respiratory neuronal networks in the ventral medulla of neonatal rats producing channelrhodopsin in Phox2b-positive cells. Pflugers Arch 2019; 471:1419-1439. [DOI: 10.1007/s00424-019-02317-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/06/2019] [Accepted: 10/04/2019] [Indexed: 12/19/2022]
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30
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Patrone LGA, Capalbo AC, Marques DA, Bícego KC, Gargaglioni LH. An age- and sex-dependent role of catecholaminergic neurons in the control of breathing and hypoxic chemoreflex during postnatal development. Brain Res 2019; 1726:146508. [PMID: 31606412 DOI: 10.1016/j.brainres.2019.146508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/23/2019] [Accepted: 10/09/2019] [Indexed: 12/27/2022]
Abstract
The respiratory system undergoes significant development during the postnatal phase. Maturation of brainstem catecholaminergic (CA) neurons is important for the control and modulation of respiratory rhythmogenesis, as well as for chemoreception in early life. We demonstrated an inhibitory role for CA neurons in CO2 chemosensitivity in neonatal and juvenile male and female rats, but information regarding their role in the hypoxic ventilatory response (HVR) is lacking. We evaluated the contribution of brainstem CA neurons in the HVR during postnatal (P) development (P7-8, P14-15 and P20-21) in male and female rats through chemical injury with conjugated saporin anti-dopamine beta-hydroxylase (DβH-SAP, 420 ng·μL-1) injected in the fourth ventricle. Ventilation (V̇E) and oxygen consumption were recorded one week after the lesion in unanesthetized rats during exposure to normoxia and hypoxia. Hypoxia reduced breathing variability in P7-8 control rats of both sexes. At P7-8, the HVR for lesioned males and females increased 27% and 24%, respectively. Additionally, the lesion reduced the normoxic breathing variability in both sexes at P7-8, but hypoxia partially reverted this effect. For P14-15, the increase in V̇E during hypoxia was 30% higher for male and 24% higher for female lesioned animals. A sex-specific difference was detected at P20-21, as lesioned males exhibited a 24% decrease in the HVR, while lesioned females experienced a 22% increase. Furthermore, the hypoxia-induced body temperature reduction was attenuated in P20-21 lesioned females. We conclude that brainstem CA neurons modulate the HRV during the postnatal phase, and possibly thermoregulation during hypoxia.
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Affiliation(s)
- Luis Gustavo A Patrone
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Aretuza C Capalbo
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Danuzia A Marques
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil.
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31
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Hasegawa S, Inoue T, Inagi R. Neuroimmune interactions and kidney disease. Kidney Res Clin Pract 2019; 38:282-294. [PMID: 31422643 PMCID: PMC6727900 DOI: 10.23876/j.krcp.19.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/28/2019] [Accepted: 06/02/2019] [Indexed: 12/15/2022] Open
Abstract
The autonomic nervous system plays critical roles in maintaining homeostasis in humans, directly regulating inflammation by altering the activity of the immune system. The cholinergic anti-inflammatory pathway is a well-studied neuroimmune interaction involving the vagus nerve. CD4-positive T cells expressing β2 adrenergic receptors and macrophages expressing the alpha 7 subunit of the nicotinic acetylcholine receptor in the spleen receive neurotransmitters such as norepinephrine and acetylcholine and are key mediators of the cholinergic anti-inflammatory pathway. Recent studies have demonstrated that vagus nerve stimulation, ultrasound, and restraint stress elicit protective effects against renal ischemia-reperfusion injury. These protective effects are induced primarily via activation of the cholinergic anti-inflammatory pathway. In addition to these immunological roles, nervous systems are directly related to homeostasis of renal physiology. Whole-kidney three-dimensional visualization using the tissue clearing technique CUBIC (clear, unobstructed brain/body imaging cocktails and computational analysis) has illustrated that renal sympathetic nerves are primarily distributed around arteries in the kidneys and denervated after ischemia-reperfusion injury. In contrast, artificial renal sympathetic denervation has a protective effect against kidney disease progression in murine models. Further studies are needed to elucidate how neural networks are involved in progression of kidney disease.
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Affiliation(s)
- Sho Hasegawa
- Division of Nephrology and Endocrinology, University of Tokyo Graduate School of Medicine, Tokyo, Japan.,Division of CKD Pathophysiology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Tsuyoshi Inoue
- Division of CKD Pathophysiology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Reiko Inagi
- Division of CKD Pathophysiology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
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32
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O'Connor KM, Lucking EF, O'Halloran KD. Chronic intermittent hypoxia‐induced hypertension: An expired hypothesis laid to rest? Exp Physiol 2019; 104:1327-1328. [DOI: 10.1113/ep087868] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 06/04/2019] [Indexed: 12/23/2022]
Affiliation(s)
- Karen M. O'Connor
- Department of Physiology, School of MedicineCollege of Medicine & Health, University College Cork Cork Ireland
| | - Eric F. Lucking
- Department of Physiology, School of MedicineCollege of Medicine & Health, University College Cork Cork Ireland
| | - Ken D. O'Halloran
- Department of Physiology, School of MedicineCollege of Medicine & Health, University College Cork Cork Ireland
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Inoue T, Tanaka S, Rosin DL, Okusa MD. Bioelectronic Approaches to Control Neuroimmune Interactions in Acute Kidney Injury. Cold Spring Harb Perspect Med 2019; 9:a034231. [PMID: 30126836 PMCID: PMC6546041 DOI: 10.1101/cshperspect.a034231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Recent studies have shown renal protective effects of bioelectric approaches, including ultrasound treatment, electrical vagus nerve stimulation, and optogenetic brainstem C1 neuron stimulation. The renal protection acquired by all three modalities was lost in splenectomized mice and/or α7 subunit of the nicotinic acetylcholine receptor-deficient mice. C1 neuron-mediated renal protection was blocked by β2-adrenergic receptor antagonist. These findings indicate that all three methods commonly, at least partially, activate the cholinergic anti-inflammatory pathway, a well-studied neuroimmune pathway. In this article, we summarize the current understanding of neuroimmune axis-mediated kidney protection in preclinical models of acute kidney injury by these three modalities. Examination of the differences among these three modalities might lead to a further elucidation of the neuroimmune axis involved in renal protection and is of interest for developing new therapeutic approaches.
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Affiliation(s)
- Tsuyoshi Inoue
- Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Shinji Tanaka
- Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
| | - Diane L Rosin
- Department of Pharmacology, University of Virginia Health System Charlottesville, Virginia 22908
| | - Mark D Okusa
- Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia Health System, Charlottesville, Virginia 22908
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Trudeau LE, El Mestikawy S. Glutamate Cotransmission in Cholinergic, GABAergic and Monoamine Systems: Contrasts and Commonalities. Front Neural Circuits 2018; 12:113. [PMID: 30618649 PMCID: PMC6305298 DOI: 10.3389/fncir.2018.00113] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/03/2018] [Indexed: 11/13/2022] Open
Abstract
Multiple discoveries made since the identification of vesicular glutamate transporters (VGLUTs) two decades ago revealed that many neuronal populations in the brain use glutamate in addition to their "primary" neurotransmitter. Such a mode of cotransmission has been detected in dopamine (DA), acetylcholine (ACh), serotonin (5-HT), norepinephrine (NE) and surprisingly even in GABA neurons. Interestingly, work performed by multiple groups during the past decade suggests that the use of glutamate as a cotransmitter takes different forms in these different populations of neurons. In the present review, we will provide an overview of glutamate cotransmission in these different classes of neurons, highlighting puzzling differences in: (1) the proportion of such neurons expressing a VGLUT in different brain regions and at different stages of development; (2) the sub-cellular localization of the VGLUT; (3) the localization of the VGLUT in relation to the neurons' other vesicular transporter; and (4) the functional role of glutamate cotransmission.
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Affiliation(s)
- Louis-Eric Trudeau
- CNS Research Group, Department of Pharmacology and Physiology, Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Salah El Mestikawy
- Department of Psychiatry, Faculty of Medicine, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.,Sorbonne Universités, Université Pierre et Marie Curie UM 119-CNRS UMR 8246-INSERM U1130, Neurosciences Paris Seine-Institut de Biologie Paris Seine (NPS-IBPS), Paris, France
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35
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Next-Generation Tools to Study Autonomic Regulation In Vivo. Neurosci Bull 2018; 35:113-123. [PMID: 30560436 DOI: 10.1007/s12264-018-0319-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/29/2018] [Indexed: 12/31/2022] Open
Abstract
The recent development of tools to decipher the intricacies of neural networks has improved our understanding of brain function. Optogenetics allows one to assess the direct outcome of activating a genetically-distinct population of neurons. Neurons are tagged with light-sensitive channels followed by photo-activation with an appropriate wavelength of light to functionally activate or silence them, resulting in quantifiable changes in the periphery. Capturing and manipulating activated neuron ensembles, is a recently-designed technique to permanently label activated neurons responsible for a physiological function and manipulate them. On the other hand, neurons can be transfected with genetically-encoded Ca2+ indicators to capture the interplay between them that modulates autonomic end-points or somatic behavior. These techniques work with millisecond temporal precision. In addition, neurons can be manipulated chronically to simulate physiological aberrations by transfecting designer G-protein-coupled receptors exclusively activated by designer drugs. In this review, we elaborate on the fundamental concepts and applications of these techniques in research.
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36
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Basting T, Xu J, Mukerjee S, Epling J, Fuchs R, Sriramula S, Lazartigues E. Glutamatergic neurons of the paraventricular nucleus are critical contributors to the development of neurogenic hypertension. J Physiol 2018; 596:6235-6248. [PMID: 30151830 PMCID: PMC6292814 DOI: 10.1113/jp276229] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/17/2018] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Recurrent periods of over-excitation in the paraventricular nucleus (PVN) of the hypothalamus could contribute to chronic over-activation of this nucleus and thus enhanced sympathetic drive. Stimulation of the PVN glutamatergic population utilizing channelrhodopsin-2 leads to an immediate frequency-dependent increase in baseline blood pressure. Partial lesions of glutamatergic neurons of the PVN (39.3%) result in an attenuated rise in blood pressure following Deoxycorticosterone acetate (DOCA)-salt treatment and reduced index of sympathetic activity. These data suggest that stimulation of PVN glutamatergic neurons is sufficient to cause autonomic dysfunction and drive the increase in blood pressure during hypertension. ABSTRACT Neuro-cardiovascular dysregulation leads to increased sympathetic activity and neurogenic hypertension. The paraventricular nucleus (PVN) of the hypothalamus is a key hub for blood pressure (BP) control, producing or relaying the increased sympathetic tone in hypertension. We hypothesize that increased central sympathetic drive is caused by chronic over-excitation of glutamatergic PVN neurons. We tested how stimulation or lesioning of excitatory PVN neurons in conscious mice affects BP, baroreflex and sympathetic activity. Glutamatergic PVN neurons were unilaterally transduced with channelrhodopsin-2 using an adeno-associated virus (CamKII-ChR2-eYFP-AAV2) in wildtype mice (n = 7) to assess the impact of acute stimulation of excitatory PVN neurons selectively on resting BP in conscious mice. Stimulation of the PVN glutamatergic population resulted in an immediate frequency-dependent (2, 10 and 20 Hz) increase in BP from baseline by ∼9 mmHg at 20 Hz stimulation (P < 0.001). Additionally, in vGlut2-cre mice glutamatergic neurons of the PVN were bilaterally lesioned utilizing a cre-dependent caspase (AAV2-flex-taCASP3-TEVp). Resting BP and urinary noradrenaline (norepinephrine) levels were then recorded in conscious mice before and after DOCA-salt hypertension. Partial lesions of glutamatergic neurons of the PVN (39.3%, P < 0.05) resulted in an attenuated rise in BP following DOCA-salt treatment (P < 0.05 at 7 day time point, n = 8). Noradrenaline levels as an index of sympathetic activity between the lesion and wildtype groups showed a significant reduction after DOCA-salt treatment in the lesioned animals (P < 0.05). These experiments suggest that stimulation of PVN glutamatergic neurons is sufficient to cause autonomic dysfunction and drive the increase in BP.
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Affiliation(s)
- Tyler Basting
- Department of Pharmacology and Experimental TherapeuticsLouisiana State University Health Sciences CenterNew OrleansLA70112USA
| | - Jiaxi Xu
- Department of Pharmacology and Experimental TherapeuticsLouisiana State University Health Sciences CenterNew OrleansLA70112USA
| | - Snigdha Mukerjee
- Department of Pharmacology and Experimental TherapeuticsLouisiana State University Health Sciences CenterNew OrleansLA70112USA
| | - Joel Epling
- Department of Pharmacology and Experimental TherapeuticsLouisiana State University Health Sciences CenterNew OrleansLA70112USA
| | - Robert Fuchs
- Department of Pharmacology and Experimental TherapeuticsLouisiana State University Health Sciences CenterNew OrleansLA70112USA
| | - Srinivas Sriramula
- Department of Pharmacology and Experimental TherapeuticsLouisiana State University Health Sciences CenterNew OrleansLA70112USA
- Department of Pharmacology and Toxicology, Brody School of MedicineEast Carolina UniversityGreenvilleNC27834USA
| | - Eric Lazartigues
- Department of Pharmacology and Experimental TherapeuticsLouisiana State University Health Sciences CenterNew OrleansLA70112USA
- Cardiovascular Center of ExcellenceLouisiana State University Health Sciences CenterNew OrleansLA70112USA
- Neuroscience Center of ExcellenceLouisiana State University Health Sciences CenterNew OrleansLA70112USA
- Southeast Louisiana Veterans Health Care SystemNew OrleansLAUSA
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Nomura K, Hiyama TY, Sakuta H, Matsuda T, Lin CH, Kobayashi K, Kobayashi K, Kuwaki T, Takahashi K, Matsui S, Noda M. [Na +] Increases in Body Fluids Sensed by Central Na x Induce Sympathetically Mediated Blood Pressure Elevations via H +-Dependent Activation of ASIC1a. Neuron 2018; 101:60-75.e6. [PMID: 30503172 DOI: 10.1016/j.neuron.2018.11.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 10/08/2018] [Accepted: 11/08/2018] [Indexed: 02/07/2023]
Abstract
Increases in sodium concentrations ([Na+]) in body fluids elevate blood pressure (BP) by enhancing sympathetic nerve activity (SNA). However, the mechanisms by which information on increased [Na+] is translated to SNA have not yet been elucidated. We herein reveal that sympathetic activation leading to BP increases is not induced by mandatory high salt intakes or the intraperitoneal/intracerebroventricular infusions of hypertonic NaCl solutions in Nax-knockout mice in contrast to wild-type mice. We identify Nax channels expressed in specific glial cells in the organum vasculosum lamina terminalis (OVLT) as the sensors detecting increases in [Na+] in body fluids and show that OVLT neurons projecting to the paraventricular nucleus (PVN) are activated via acid-sensing ion channel 1a (ASIC1a) by H+ ions exported from Nax-positive glial cells. The present results provide an insight into the neurogenic mechanisms responsible for salt-induced BP elevations.
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Affiliation(s)
- Kengo Nomura
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Takeshi Y Hiyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Hiraki Sakuta
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Takashi Matsuda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Chia-Hao Lin
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - Kazuto Kobayashi
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Kunihiko Takahashi
- Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Shigeyuki Matsui
- Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan; Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan.
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Role of C1 neurons in anti-inflammatory reflex: Mediation between afferents and efferents. Neurosci Res 2018; 136:6-12. [DOI: 10.1016/j.neures.2018.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 04/24/2018] [Accepted: 05/07/2018] [Indexed: 12/21/2022]
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Magalhães KS, Spiller PF, da Silva MP, Kuntze LB, Paton JFR, Machado BH, Moraes DJA. Locus Coeruleus as a vigilance centre for active inspiration and expiration in rats. Sci Rep 2018; 8:15654. [PMID: 30353035 PMCID: PMC6199338 DOI: 10.1038/s41598-018-34047-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/08/2018] [Indexed: 01/05/2023] Open
Abstract
At rest, inspiration is an active process while expiration is passive. However, high chemical drive (hypercapnia or hypoxia) activates central and peripheral chemoreceptors triggering reflex increases in inspiration and active expiration. The Locus Coeruleus contains noradrenergic neurons (A6 neurons) that increase their firing frequency when exposed to hypercapnia and hypoxia. Using recently developed neuronal hyperpolarising technology in conscious rats, we tested the hypothesis that A6 neurons are a part of a vigilance centre for controlling breathing under high chemical drive and that this includes recruitment of active inspiration and expiration in readiness for flight or fight. Pharmacogenetic inhibition of A6 neurons was without effect on resting and on peripheral chemoreceptors-evoked inspiratory, expiratory and ventilatory responses. On the other hand, the number of sighs evoked by systemic hypoxia was reduced. In the absence of peripheral chemoreceptors, inhibition of A6 neurons during hypercapnia did not affect sighing, but reduced both the magnitude and incidence of active expiration, and the frequency and amplitude of inspiration. These changes reduced pulmonary ventilation. Our data indicated that A6 neurons exert a CO2-dependent modulation of expiratory drive. The data also demonstrate that A6 neurons contribute to the CO2-evoked increases in the inspiratory motor output and hypoxia-evoked sighing.
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Affiliation(s)
- Karolyne S Magalhães
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Pedro F Spiller
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Melina P da Silva
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luciana B Kuntze
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Benedito H Machado
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Davi J A Moraes
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil.
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Breathing responses produced by optogenetic stimulation of adrenergic C1 neurons are dependent on the connection with preBötzinger complex in rats. Pflugers Arch 2018; 470:1659-1672. [DOI: 10.1007/s00424-018-2186-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/11/2018] [Accepted: 07/20/2018] [Indexed: 01/14/2023]
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Abstract
Rhythmicity is a universal timing mechanism in the brain, and the rhythmogenic mechanisms are generally dynamic. This is illustrated for the neuronal control of breathing, a behavior that occurs as a one-, two-, or three-phase rhythm. Each breath is assembled stochastically, and increasing evidence suggests that each phase can be generated independently by a dedicated excitatory microcircuit. Within each microcircuit, rhythmicity emerges through three entangled mechanisms: ( a) glutamatergic transmission, which is amplified by ( b) intrinsic bursting and opposed by ( c) concurrent inhibition. This rhythmogenic triangle is dynamically tuned by neuromodulators and other network interactions. The ability of coupled oscillators to reconfigure and recombine may allow breathing to remain robust yet plastic enough to conform to nonventilatory behaviors such as vocalization, swallowing, and coughing. Lessons learned from the respiratory network may translate to other highly dynamic and integrated rhythmic systems, if approached one breath at a time.
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Affiliation(s)
- Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington 98101, USA;
| | - Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington 98101, USA;
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Adamantidis A, Lüthi A. Optogenetic Dissection of Sleep-Wake States In Vitro and In Vivo. Handb Exp Pharmacol 2018; 253:125-151. [PMID: 29687163 DOI: 10.1007/164_2018_94] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Optogenetic tools have revolutionized insights into the fundamentals of brain function. This is particularly true for our current understanding of sleep-wake regulation and sleep rhythms. This is illustrated here through a comprehensive and step-by-step review over the major brain areas involved in transitions between sleep and wake states and in sleep rhythmogenesis.
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Affiliation(s)
- Antoine Adamantidis
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, Switzerland. .,Department of Clinical Research (DKF), University of Bern, Bern, Switzerland.
| | - Anita Lüthi
- Department of Fundamental Neurosciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
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Sunshine MD, Ganji CN, Reier PJ, Fuller DD, Moritz CT. Intraspinal microstimulation for respiratory muscle activation. Exp Neurol 2018; 302:93-103. [PMID: 29305050 DOI: 10.1016/j.expneurol.2017.12.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 12/20/2017] [Accepted: 12/26/2017] [Indexed: 11/17/2022]
Abstract
A complex propriospinal network is synaptically coupled to phrenic and intercostal motoneurons, and this makes it difficult to predict how gray matter intraspinal microstimulation (ISMS) will recruit respiratory motor units. We therefore mapped the cervical and high thoracic gray matter at locations which ISMS activates diaphragm (DIA) and external intercostal (EIC) motor units. Respiratory muscle electromyography (EMG) was recorded in anesthetized female spinally intact adult rats while a stimulating electrode was advanced ventrally into the spinal cord in 600μm increments. At each depth, single biphasic stimuli were delivered at 10-90μA during both the inspiratory and expiratory phase independently. Twenty electrode tracks were made from C2-T1 at medial and lateral gray matter locations. During inspiration, ISMS evoked DIA and EIC activity throughout C2-T1 gray matter locations, with mutual activation occurring at 17±9% of sites. During inspiratory phase ISMS the average latency for DIA activation was 4.40±0.70ms. During the expiratory phase, ISMS-induced DIA activation required electrodes to be in close proximity to the phrenic motoneuron pool, and average activation latency was 3.30±0.50ms. We conclude that appropriately targeted ISMS can co-activate DIA and EIC motor units, and endogenous respiratory drive has a powerful impact on ISMS-induced respiratory motor unit activation. The long latency diaphragm motor unit activation suggests the presence of a complex propriospinal network that can modulate phrenic motor output.
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Affiliation(s)
- Michael D Sunshine
- Rehabilitation Medicine, University of Washington, Seattle, WA, United States; Center for Sensorimotor Neural Engineering (CSNE), Seattle, WA, United States; Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, United States.
| | - Comron N Ganji
- Rehabilitation Medicine, University of Washington, Seattle, WA, United States; Center for Sensorimotor Neural Engineering (CSNE), Seattle, WA, United States
| | - Paul J Reier
- Neuroscience, University of Florida, Gainesville, FL, United States
| | - David D Fuller
- Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, United States; Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, FL, United States
| | - Chet T Moritz
- Rehabilitation Medicine, University of Washington, Seattle, WA, United States; Center for Sensorimotor Neural Engineering (CSNE), Seattle, WA, United States; Physiology & Biophysics, University of Washington, Seattle, WA, United States; University of Washington Institute for Neuroengineering (UWIN), University of Washington, Seattle, WA, United States
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Dergacheva O, Mendelowitz D. Combined hypoxia and hypercapnia, but not hypoxia alone, suppresses neurotransmission from orexin to hypothalamic paraventricular spinally-projecting neurons in weanling rats. Brain Res 2017; 1679:33-38. [PMID: 29162453 DOI: 10.1016/j.brainres.2017.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/03/2017] [Accepted: 11/16/2017] [Indexed: 12/30/2022]
Abstract
Both orexin neurons in the lateral hypothalamus and spinally-projecting pre-sympathetic neurons (PSNs) in the paraventricular nucleus of the hypothalamus (PVN) play an important role in the regulation of cardiovascular function under normal conditions and during cardiovascular challenges such as hypoxia and/or hypercapnia. We have previously established, using selective optogenetic excitation of orexin neurons and pathways, there is a heterogeneous neurotransmission from orexin neurons to PSNs in the PVN. This study was undertaken to test whether this pathway is altered by acute exposure to hypoxia alone and/or combined hypoxia and hypercapnia (H/H). To test this hypothesis, we selectively expressed channelrhodopsin-2 (ChR2) in orexin neurons in the lateral hypothalamus and photoactivated ChR2-expressing fibers to evoke postsynaptic currents in spinally-projecting PSNs in an in vitro slice preparation in rats. In accordance with previously published data, two subpopulations of spinally-projecting PSNs were established, including those with glutamatergic or GABAergic inputs from orexin neurons. Hypoxia alone did not alter the peak amplitude of either glutamatergic or GABAergic neurotransmission, however, H/H significantly inhibited both glutamatergic and GABAergic neurotransmission from orexin neurons to SPNs. In conclusion, H/H may modulate cardiovascular function by affecting heterogeneous pathways from orexin neurons to spinally-projecting PSNs in the PVN.
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Affiliation(s)
- Olga Dergacheva
- *Department of Pharmacology and Physiology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA.
| | - David Mendelowitz
- *Department of Pharmacology and Physiology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA
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Central Network Dynamics Regulating Visceral and Humoral Functions. J Neurosci 2017; 37:10848-10854. [PMID: 29118214 DOI: 10.1523/jneurosci.1833-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/03/2017] [Accepted: 10/08/2017] [Indexed: 02/07/2023] Open
Abstract
The brain processes information from the periphery and regulates visceral and immune activity to maintain internal homeostasis, optimally respond to a dynamic external environment, and integrate these functions with ongoing behavior. In addition to its relevance for survival, this integration underlies pathology as evidenced by diseases exhibiting comorbid visceral and psychiatric symptoms. Advances in neuroanatomical mapping, genetically specific neuronal manipulation, and neural network recording are overcoming the challenges of dissecting complex circuits that underlie this integration and deciphering their function. Here we focus on reciprocal communication between the brain and urological, gastrointestinal, and immune systems. These studies are revealing how autonomic activity becomes integrated into behavior as part of a social strategy, how the brain regulates innate immunity in response to stress, and how drugs impact emotion and gastrointestinal function. These examples highlight the power of the functional organization of circuits at the interface of the brain and periphery.
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Stornetta RL, Guyenet PG. C1 neurons: a nodal point for stress? Exp Physiol 2017; 103:332-336. [PMID: 29080216 DOI: 10.1113/ep086435] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/20/2017] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the topic of this review? The C1 neurons (C1) innervate sympathetic and parasympathetic preganglionic neurons plus numerous brain nuclei implicated in stress, arousal and autonomic regulations. We consider here the contribution of C1 to stress-induced responses. What advances does it highlight? C1 activation is required for blood pressure stability during hypoxia and mild hemorrhage which exemplifies their homeostatic function. During restraint stress, C1 activate the splenic anti-inflammatory pathway resulting in tissue protection against ischemic injury. This effect, along with glucose release and, possibly, arousal are examples of adaptive non-homeostatic responses to stress that are also mediated by C1. The C1 cells are catecholaminergic and glutamatergic neurons located in the rostral ventrolateral medulla. Collectively, these neurons innervate sympathetic and parasympathetic preganglionic neurons, the hypothalamic paraventricular nucleus and countless brain structures involved in autonomic regulation, arousal and stress. Optogenetic inhibition of rostral C1 neurons has little effect on blood pressure (BP) at rest in conscious rats but produces large reductions in BP when the animals are anaesthetized or exposed to hypoxia. Optogenetic C1 stimulation increases BP and produces arousal from non-rapid eye movement sleep. C1 cell stimulation mimics the effect of restraint stress to attenuate kidney injury caused by renal ischaemia-reperfusion. These effects are mediated by the sympathetic nervous system through the spleen and eliminated by silencing the C1 neurons. These few examples illustrate that, depending on the nature of the stress, the C1 cells mediate adaptive responses of a homeostatic or allostatic nature.
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Affiliation(s)
- Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
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Impaired chemosensory control of breathing after depletion of bulbospinal catecholaminergic neurons in rats. Pflugers Arch 2017; 470:277-293. [PMID: 29032505 DOI: 10.1007/s00424-017-2078-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/11/2017] [Accepted: 10/09/2017] [Indexed: 02/07/2023]
Abstract
Bulbospinal catecholaminergic neurons located in the rostral aspect of the ventrolateral medulla (C1 neurons) or within the ventrolateral pons (A5 neurons) are involved in the regulation of blood pressure and sympathetic outflow. A stimulus that commonly activates the C1 or A5 neurons is hypoxia, which is also involved in breathing activation. Although pharmacological and optogenetic evidence suggests that catecholaminergic neurons also regulate breathing, a specific contribution of the bulbospinal neurons to respiratory control has not been demonstrated. Therefore, in the present study, we evaluated whether the loss of bulbospinal catecholaminergic C1 and A5 cells affects cardiorespiratory control during resting, hypoxic (8% O2), and hypercapnic (7% CO2) conditions in unanesthetized rats. Thoracic spinal cord (T4-T8) injections of the immunotoxin anti-dopamine β-hydroxylase-saporin (anti-DβH-SAP-2.4 ng/100 nl) and the retrograde tracer Fluor-Gold or ventrolateral pontine injections of 6-OHDA were performed in adult male Wistar rats (250-280 g, N = 7-9/group). Anti-DβH-SAP or 6-OHDA eliminated most bulbospinal C1 and A5 neurons or A5 neurons, respectively. Serotonergic neurons and astrocytes were spared. Depletion of the bulbospinal catecholaminergic cells did not change cardiorespiratory variables under resting condition, but it did affect the response to hypoxia and hypercapnia. Specifically, the increase in the ventilation, the number of sighs, and the tachycardia were reduced, but the MAP increased during hypoxia in anti-DβH-SAP-treated rats. Our data reveal that the bulbospinal catecholaminergic neurons (A5 and C1) facilitate the ventilatory reflex to hypoxia and hypercapnia.
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The effect of atomoxetine, a selective norepinephrine reuptake inhibitor, on respiratory arrest and cardiorespiratory function in the DBA/1 mouse model of SUDEP. Epilepsy Res 2017; 137:139-144. [PMID: 28844345 DOI: 10.1016/j.eplepsyres.2017.08.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 06/22/2017] [Accepted: 08/12/2017] [Indexed: 11/20/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a significant public health burden. The mechanisms of SUDEP are elusive, although cardiorespiratory dysfunction is a likely contributor. Clinical and animal studies indicate that seizure-induced respiratory arrest (S-IRA) is the primary event leading to death in many SUDEP cases. Our prior studies demonstrated that intraperitoneal (IP) injection of atomoxetine, a norepinephrine reuptake inhibitor (NRI) widely used to treat attention deficit hyperactivity disorder, suppresses S-IRA in DBA/1 mice. In the current study, we injected atomoxetine intracerebroventricularly (ICV) and measured its effect on S-IRA in DBA/1 mice to determine its central effects. Additionally, to test our hypothesis that atomoxetine reduces S-IRA via altering cardiorespiratory function, we examined the effect of atomoxetine on respiratory and cardiac function using non-invasive plethysmography and ECG in anesthetized DBA/1 mice, and on blood pressure and heart rate using a tail-cuff system in conscious DBA/1 mice. ICV administration of atomoxetine at 200-250nmol significantly reduced S-IRA evoked by acoustic stimulation in DBA/1 mice, consistent with a central atomoxetine effect on S-IRA. Peripheral atomoxetine administration at a dosage that reduces S-IRA (15mg/kg, IP) slightly increased basal ventilation and the ventilatory response to 7% CO2, but exerted no effect on heart rate in anesthetized DBA/1 mice. IP injection of atomoxetine produced no effect on the heart rate and blood pressures in conscious mice. These data suggest that atomoxetine suppresses S-IRA through direct effects on the CNS and potentially through enhanced lung ventilation in DBA/1 mice.
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50
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Zhang H, Zhao H, Feng HJ. Atomoxetine, a norepinephrine reuptake inhibitor, reduces seizure-induced respiratory arrest. Epilepsy Behav 2017; 73:6-9. [PMID: 28605634 PMCID: PMC5545072 DOI: 10.1016/j.yebeh.2017.04.046] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 04/26/2017] [Accepted: 04/26/2017] [Indexed: 12/31/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a devastating epilepsy complication, and no effective preventive strategies are currently available for this fatal disorder. Clinical and animal studies of SUDEP demonstrate that seizure-induced respiratory arrest (S-IRA) is the primary event leading to death after generalized seizures in many cases. Enhancing brain levels of serotonin reduces S-IRA in animal models relevant to SUDEP, including the DBA/1 mouse. Given that serotonin in the brain plays an important role in modulating respiration and arousal, these findings suggest that deficits in respiration and/or arousal may contribute to S-IRA. It is well known that norepinephrine is an important neurotransmitter that modulates respiration and arousal in the brain as well. Therefore, we hypothesized that enhancing noradrenergic neurotransmission suppresses S-IRA. To test this hypothesis, we examined the effect of atomoxetine, a norepinephrine reuptake inhibitor (NRI), on S-IRA evoked by either acoustic stimulation or pentylenetetrazole in DBA/1 mice. We report the original observation that atomoxetine specifically suppresses S-IRA without altering the susceptibility to seizures evoked by acoustic stimulation, and atomoxetine also reduces S-IRA evoked by pentylenetetrazole in DBA/1 mice. Our data suggest that the noradrenergic signaling is importantly involved in S-IRA, and that atomoxetine, a medication widely used to treat attention deficit hyperactivity disorder (ADHD), is potentially useful to prevent SUDEP.
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Affiliation(s)
- Honghai Zhang
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA,Department of Anesthesia, Hangzhou First People's Hospital, Nanjing Medical University, Hangzhou, China
| | - Haiting Zhao
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA,Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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