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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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Dereli AS, Oh AYS, McMullan S, Kumar NN. Galaninergic and hypercapnia-activated neuronal projections to the ventral respiratory column. Brain Struct Funct 2024; 229:1121-1142. [PMID: 38578351 PMCID: PMC11147908 DOI: 10.1007/s00429-024-02782-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 02/26/2024] [Indexed: 04/06/2024]
Abstract
In mammals, the ventral respiratory column (VRC) plays a pivotal role in integrating neurochemically diverse inputs from brainstem and forebrain regions to generate respiratory motor patterns. VRC microinjection of the neuropeptide galanin has been reported to dampen carbon dioxide (CO2)-mediated chemoreflex responses. Additionally, we previously demonstrated that galaninergic neurons in the retrotrapezoid nucleus (RTN) are implicated in the adaptive response to hypercapnic stimuli, suggesting a link between RTN neuroplasticity and increased neuronal drive to the VRC. VRC neurons express galanin receptor 1, suggesting potential regulatory action by galanin, however, the precise galaninergic chemoreceptor-VRC circuitry remains to be determined. This study aimed to identify sources of galaninergic input to the VRC that contribute to central respiratory chemoreception. We employed a combination of retrograde neuronal tracing, in situ hybridisation and immunohistochemistry to investigate VRC-projecting neurons that synthesise galanin mRNA. In an additional series of experiments, we used acute hypercapnia exposure (10% CO2, 1 h) and c-Fos immunohistochemistry to ascertain which galaninergic nuclei projecting to the VRC are activated. Our findings reveal that a total of 30 brain nuclei and 51 subnuclei project to the VRC, with 12 of these containing galaninergic neurons, including the RTN. Among these galaninergic populations, only a subset of the RTN neurons (approximately 55%) exhibited activation in response to acute hypercapnia. Our findings highlight that the RTN is the likely source of galaninergic transmission to the VRC in response to hypercapnic stimuli.
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Affiliation(s)
- Ayse S Dereli
- Department of Pharmacology, School of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Alice Y S Oh
- Department of Pharmacology, School of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Simon McMullan
- Macquarie Medical School, Macquarie University, Sydney, Australia
| | - Natasha N Kumar
- Department of Pharmacology, School of Biomedical Sciences, University of New South Wales, Sydney, Australia.
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Korkutata M, De Luca R, Fitzgerald B, Arrigoni E, Scammell TE. Afferent projections to the Calca /CGRP-expressing parabrachial neurons in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.593004. [PMID: 38766214 PMCID: PMC11100666 DOI: 10.1101/2024.05.07.593004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The parabrachial nucleus (PB), located in the dorsolateral pons, contains primarily glutamatergic neurons which regulate responses to a variety of interoceptive and cutaneous sensory signals. The lateral PB subpopulation expressing the Calca gene which produces the neuropeptide calcitonin gene-related peptide (CGRP) relays signals related to threatening stimuli such as hypercarbia, pain, and nausea, yet the afferents to these neurons are only partially understood. We mapped the afferent projections to the lateral part of the PB in mice using conventional cholera toxin B subunit (CTb) retrograde tracing, and then used conditional rabies virus retrograde tracing to map monosynaptic inputs specifically targeting the PB Calca /CGRP neurons. Using vesicular GABA (vGAT) and glutamate (vGLUT2) transporter reporter mice, we found that lateral PB neurons receive GABAergic afferents from regions such as the lateral part of the central nucleus of the amygdala, lateral dorsal subnucleus of the bed nucleus of the stria terminalis, substantia innominata, and the ventrolateral periaqueductal gray. Additionally, they receive glutamatergic afferents from the infralimbic and insular cortex, paraventricular nucleus, parasubthalamic nucleus, trigeminal complex, medullary reticular nucleus, and nucleus of the solitary tract. Using anterograde tracing and confocal microscopy, we then identified close axonal appositions between these afferents and PB Calca /CGRP neurons. Finally, we used channelrhodopsin-assisted circuit mapping to test whether some of these inputs directly synapse upon the PB Calca /CGRP neurons. These findings provide a comprehensive neuroanatomical framework for understanding the afferent projections regulating the PB Calca /CGRP neurons.
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Janes TA, Cardani S, Saini JK, Pagliardini S. Etonogestrel promotes respiratory recovery in an in vivo rat model of central chemoreflex impairment. Acta Physiol (Oxf) 2024; 240:e14093. [PMID: 38258900 DOI: 10.1111/apha.14093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/11/2023] [Accepted: 01/01/2024] [Indexed: 01/24/2024]
Abstract
AIM The central CO2 chemoreflex is a vital component of respiratory control networks, providing excitatory drive during resting conditions and challenges to blood gas homeostasis. The retrotrapezoid nucleus is a crucial hub for CO2 chemosensitivity; its ablation or inhibition attenuates CO2 chemoreflexes and diminishes restful breathing. Similar phenotypes characterize certain hypoventilation syndromes, suggesting underlying retrotrapezoid nucleus impairment in these disorders. Progesterone stimulates restful breathing and CO2 chemoreflexes. However, its mechanisms and sites of actions remain unknown and the experimental use of synthetic progestins in patients and animal models have been met with mixed respiratory outcomes. METHODS We investigated whether acute or chronic administration of the progestinic drug, etonogestrel, could rescue respiratory chemoreflexes following selective lesion of the retrotrapezoid nucleus with saporin toxin. Adult female Sprague Dawley rats were grouped based on lesion size determined by the number of surviving chemosensitive neurons, and ventilatory responses were measured by whole body plethysmography. RESULTS Ventilatory responses to hypercapnia (but not hypoxia) were compromised in a lesion-dependent manner. Chronic etonogestrel treatment improved CO2 chemosensitivity selectively in rats with moderate lesion, suggesting that a residual number of chemosensitive neurons are required for etonogestrel-induced CO2 chemoreflex recovery. CONCLUSION This study provides new evidence for the use of progestins as respiratory stimulants under conditions of central hypoventilation and provides a new testable model for assessing the mechanism of action of progestins in the respiratory network.
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Affiliation(s)
- Tara A Janes
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Silvia Cardani
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Jasmeen K Saini
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Silvia Pagliardini
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
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5
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Oliveira LM, Moreira TS, Takakura AC. Interaction between Kölliker-Fuse/A7 and the parafacial respiratory region on the control of respiratory regulation. Respir Physiol Neurobiol 2024; 320:104201. [PMID: 38043841 DOI: 10.1016/j.resp.2023.104201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/24/2023] [Accepted: 11/29/2023] [Indexed: 12/05/2023]
Abstract
Respiration is regulated by various types of neurons located in the pontine-medullary regions. The Kölliker-Fuse (KF)/A7 noradrenergic neurons play a role in modulating the inspiratory cycle by influencing the respiratory output. These neurons are interconnected and may also project to brainstem and spinal cord, potentially involved in regulating the post-inspiratory phase. In the present study, we hypothesize that the parafacial (pF) neurons, in conjunction with adrenergic mechanisms originating from the KF/A7 region, may provide the neurophysiological basis for breathing modulation. We conducted experiments using urethane-anesthetized, vagotomized, and artificially ventilated male Wistar rats. Injection of L-glutamate into the KF/A7 region resulted in inhibition of inspiratory activity, and a prolonged and high-amplitude genioglossal activity (GGEMG). Blockade of the α1 adrenergic receptors (α1-AR) or the ionotropic glutamatergic receptors in the pF region decrease the activity of the GGEMG without affecting inspiratory cessation. In contrast, blockade of α2-AR in the pF region extended the duration of GG activity. Notably, the inspiratory and GGEMG activities induced by KF/A7 stimulation were completely blocked by bilateral blockade of glutamatergic receptors in the Bötzinger complex (BötC). While our study found a limited role for α1 and α2 adrenergic receptors at the pF level in modulating the breathing response to KF/A7 stimulation, it became evident that BötC neurons are responsible for the respiratory effects induced by KF/A7 stimulation.
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Affiliation(s)
- Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP 05508, Brazil; Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Avenue, JMB10, Seattle, WA 98101, USA
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP 05508, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP 05508, Brazil.
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Harmata GI, Rhone AE, Kovach CK, Kumar S, Mowla MR, Sainju RK, Nagahama Y, Oya H, Gehlbach BK, Ciliberto MA, Mueller RN, Kawasaki H, Pattinson KT, Simonyan K, Davenport PW, Howard MA, Steinschneider M, Chan AC, Richerson GB, Wemmie JA, Dlouhy BJ. Failure to breathe persists without air hunger or alarm following amygdala seizures. JCI Insight 2023; 8:e172423. [PMID: 37788112 PMCID: PMC10721319 DOI: 10.1172/jci.insight.172423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/29/2023] [Indexed: 10/05/2023] Open
Abstract
Postictal apnea is thought to be a major cause of sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying postictal apnea are unknown. To understand causes of postictal apnea, we used a multimodal approach to study brain mechanisms of breathing control in 20 patients (ranging from pediatric to adult) undergoing intracranial electroencephalography for intractable epilepsy. Our results indicate that amygdala seizures can cause postictal apnea. Moreover, we identified a distinct region within the amygdala where electrical stimulation was sufficient to reproduce prolonged breathing loss persisting well beyond the end of stimulation. The persistent apnea was resistant to rising CO2 levels, and air hunger failed to occur, suggesting impaired CO2 chemosensitivity. Using es-fMRI, a potentially novel approach combining electrical stimulation with functional MRI, we found that amygdala stimulation altered blood oxygen level-dependent (BOLD) activity in the pons/medulla and ventral insula. Together, these findings suggest that seizure activity in a focal subregion of the amygdala is sufficient to suppress breathing and air hunger for prolonged periods of time in the postictal period, likely via brainstem and insula sites involved in chemosensation and interoception. They further provide insights into SUDEP, may help identify those at greatest risk, and may lead to treatments to prevent SUDEP.
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Affiliation(s)
- Gail I.S. Harmata
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Pharmacological Sciences Training Program
- Department of Psychiatry
| | | | | | | | | | | | | | - Hiroyuki Oya
- Department of Neurosurgery
- Iowa Neuroscience Institute
| | | | | | - Rashmi N. Mueller
- Department of Neurosurgery
- Department of Anesthesia, University of Iowa, Iowa City, Iowa, USA
| | | | - Kyle T.S. Pattinson
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Kristina Simonyan
- Department of Otolaryngology–Head and Neck Surgery, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Paul W. Davenport
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
| | - Matthew A. Howard
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
| | | | | | - George B. Richerson
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Neurology
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
- Department of Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - John A. Wemmie
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Psychiatry
- Department of Internal Medicine
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Brian J. Dlouhy
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
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Burtscher J, Citherlet T, Camacho-Cardenosa A, Camacho-Cardenosa M, Raberin A, Krumm B, Hohenauer E, Egg M, Lichtblau M, Müller J, Rybnikova EA, Gatterer H, Debevec T, Baillieul S, Manferdelli G, Behrendt T, Schega L, Ehrenreich H, Millet GP, Gassmann M, Schwarzer C, Glazachev O, Girard O, Lalande S, Hamlin M, Samaja M, Hüfner K, Burtscher M, Panza G, Mallet RT. Mechanisms underlying the health benefits of intermittent hypoxia conditioning. J Physiol 2023. [PMID: 37860950 DOI: 10.1113/jp285230] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023] Open
Abstract
Intermittent hypoxia (IH) is commonly associated with pathological conditions, particularly obstructive sleep apnoea. However, IH is also increasingly used to enhance health and performance and is emerging as a potent non-pharmacological intervention against numerous diseases. Whether IH is detrimental or beneficial for health is largely determined by the intensity, duration, number and frequency of the hypoxic exposures and by the specific responses they engender. Adaptive responses to hypoxia protect from future hypoxic or ischaemic insults, improve cellular resilience and functions, and boost mental and physical performance. The cellular and systemic mechanisms producing these benefits are highly complex, and the failure of different components can shift long-term adaptation to maladaptation and the development of pathologies. Rather than discussing in detail the well-characterized individual responses and adaptations to IH, we here aim to summarize and integrate hypoxia-activated mechanisms into a holistic picture of the body's adaptive responses to hypoxia and specifically IH, and demonstrate how these mechanisms might be mobilized for their health benefits while minimizing the risks of hypoxia exposure.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Tom Citherlet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Alba Camacho-Cardenosa
- Department of Physical Education and Sports, Faculty of Sports Science, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
| | - Marta Camacho-Cardenosa
- Clinical Management Unit of Endocrinology and Nutrition - GC17, Maimónides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
| | - Antoine Raberin
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Bastien Krumm
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Erich Hohenauer
- Rehabilitation and Exercise Science Laboratory (RES lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
- International University of Applied Sciences THIM, Landquart, Switzerland
- Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Margit Egg
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Mona Lichtblau
- Department of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Julian Müller
- Department of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Elena A Rybnikova
- Pavlov Institute of Physiology, Russian Academy of Sciences, St Petersburg, Russia
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
- Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT TIROL-Private University for Health Sciences and Health Technology, Hall in Tirol, Austria
| | - Tadej Debevec
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
- Department of Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Sebastien Baillieul
- Service Universitaire de Pneumologie Physiologie, University of Grenoble Alpes, Inserm, Grenoble, France
| | | | - Tom Behrendt
- Chair Health and Physical Activity, Department of Sport Science, Institute III, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Lutz Schega
- Chair Health and Physical Activity, Department of Sport Science, Institute III, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Hannelore Ehrenreich
- Clinical Neuroscience, University Medical Center and Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Christoph Schwarzer
- Institute of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Oleg Glazachev
- Department of Normal Physiology, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, Western Australia, Australia
| | - Sophie Lalande
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA
| | - Michael Hamlin
- Department of Tourism, Sport and Society, Lincoln University, Christchurch, New Zealand
| | - Michele Samaja
- Department of Health Science, University of Milan, Milan, Italy
| | - Katharina Hüfner
- Department of Psychiatry, Psychotherapy, Psychosomatics and Medical Psychology, University Hospital for Psychiatry II, Medical University of Innsbruck, Innsbruck, Austria
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Gino Panza
- The Department of Health Care Sciences, Program of Occupational Therapy, Wayne State University, Detroit, MI, USA
- John D. Dingell VA Medical Center Detroit, Detroit, MI, USA
| | - Robert T Mallet
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
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Gonye EC, Bayliss DA. Criteria for central respiratory chemoreceptors: experimental evidence supporting current candidate cell groups. Front Physiol 2023; 14:1241662. [PMID: 37719465 PMCID: PMC10502317 DOI: 10.3389/fphys.2023.1241662] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 08/16/2023] [Indexed: 09/19/2023] Open
Abstract
An interoceptive homeostatic system monitors levels of CO2/H+ and provides a proportionate drive to respiratory control networks that adjust lung ventilation to maintain physiologically appropriate levels of CO2 and rapidly regulate tissue acid-base balance. It has long been suspected that the sensory cells responsible for the major CNS contribution to this so-called respiratory CO2/H+ chemoreception are located in the brainstem-but there is still substantial debate in the field as to which specific cells subserve the sensory function. Indeed, at the present time, several cell types have been championed as potential respiratory chemoreceptors, including neurons and astrocytes. In this review, we advance a set of criteria that are necessary and sufficient for definitive acceptance of any cell type as a respiratory chemoreceptor. We examine the extant evidence supporting consideration of the different putative chemoreceptor candidate cell types in the context of these criteria and also note for each where the criteria have not yet been fulfilled. By enumerating these specific criteria we hope to provide a useful heuristic that can be employed both to evaluate the various existing respiratory chemoreceptor candidates, and also to focus effort on specific experimental tests that can satisfy the remaining requirements for definitive acceptance.
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Affiliation(s)
- Elizabeth C. Gonye
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States
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9
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Jones AA, Marino GM, Spears AR, Arble DM. The Molecular Circadian Clock of Phox2b-expressing Cells Drives Daily Variation of the Hypoxic but Not Hypercapnic Ventilatory Response in Mice. FUNCTION 2023; 4:zqad023. [PMID: 37342417 PMCID: PMC10278984 DOI: 10.1093/function/zqad023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 06/22/2023] Open
Abstract
While the suprachiasmatic nucleus (SCN) controls 24-h rhythms in breathing, including minute ventilation (VE), the mechanisms by which the SCN drives these daily changes are not well understood. Moreover, the extent to which the circadian clock regulates hypercapnic and hypoxic ventilatory chemoreflexes is unknown. We hypothesized that the SCN regulates daily breathing and chemoreflex rhythms by synchronizing the molecular circadian clock of cells. We used whole-body plethysmography to assess ventilatory function in transgenic BMAL1 knockout (KO) mice to determine the role of the molecular clock in regulating daily rhythms in ventilation and chemoreflex. Unlike their wild-type littermates, BMAL1 KO mice exhibited a blunted daily rhythm in VE and failed to demonstrate daily variation in the hypoxic ventilatory response (HVR) or hypercapnic ventilatory response (HCVR). To determine if the observed phenotype was mediated by the molecular clock of key respiratory cells, we then assessed ventilatory rhythms in BMAL1fl/fl; Phox2bCre/+ mice, which lack BMAL1 in all Phox2b-expressing chemoreceptor cells (hereafter called BKOP). BKOP mice lacked daily variation in HVR, similar to BMAL1 KO mice. However, unlike BMAL1 KO mice, BKOP mice exhibited circadian variations in VE and HCVR comparable to controls. These data indicate that the SCN regulates daily rhythms in VE, HVR, and HCVR, in part, through the synchronization of the molecular clock. Moreover, the molecular clock of Phox2b-expressing cells is specifically necessary for daily variation in the hypoxic chemoreflex. These findings suggest that disruption of circadian biology may undermine respiratory homeostasis, which, in turn, may have clinical implications for respiratory disease.
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Affiliation(s)
- Aaron A Jones
- Department of Biological Sciences, Marquette University, WI 53233, USA
| | | | - Allison R Spears
- Department of Biological Sciences, Marquette University, WI 53233, USA
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10
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Krohn F, Novello M, van der Giessen RS, De Zeeuw CI, Pel JJM, Bosman LWJ. The integrated brain network that controls respiration. eLife 2023; 12:83654. [PMID: 36884287 PMCID: PMC9995121 DOI: 10.7554/elife.83654] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/29/2023] [Indexed: 03/09/2023] Open
Abstract
Respiration is a brain function on which our lives essentially depend. Control of respiration ensures that the frequency and depth of breathing adapt continuously to metabolic needs. In addition, the respiratory control network of the brain has to organize muscular synergies that integrate ventilation with posture and body movement. Finally, respiration is coupled to cardiovascular function and emotion. Here, we argue that the brain can handle this all by integrating a brainstem central pattern generator circuit in a larger network that also comprises the cerebellum. Although currently not generally recognized as a respiratory control center, the cerebellum is well known for its coordinating and modulating role in motor behavior, as well as for its role in the autonomic nervous system. In this review, we discuss the role of brain regions involved in the control of respiration, and their anatomical and functional interactions. We discuss how sensory feedback can result in adaptation of respiration, and how these mechanisms can be compromised by various neurological and psychological disorders. Finally, we demonstrate how the respiratory pattern generators are part of a larger and integrated network of respiratory brain regions.
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Affiliation(s)
- Friedrich Krohn
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Manuele Novello
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Johan J M Pel
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
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11
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Nokes B, Cooper J, Cao M. Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology. Expert Rev Respir Med 2022; 16:917-929. [PMID: 35949101 DOI: 10.1080/17476348.2022.2112669] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Introduction The recent continuous positive airway pressure (CPAP) crisis has highlighted the need for alternative obstructive sleep apnea (OSA) therapies. This article serves to review OSA pathophysiology and how sleep apnea mechanisms may be utilized to individualize alternative treatment options.Areas covered: The research highlighted below focuses on 1) mechanisms of OSA pathogenesis and 2) CPAP alternative therapies based on mechanism of disease. We reviewed PubMed from inception to July 2022 for relevant articles pertaining to OSA pathogenesis, sleep apnea surgery, as well as sleep apnea alternative therapies.Expert opinion: Although the field of individualized OSA treatment is still in its infancy, much has been learned about OSA traits and how they may be targeted based on a patient's physiology and preferences. While CPAP remains the gold-standard for OSA management, several novel alternatives are emerging. CPAP is a universal treatment approach for all severities of OSA. We believe that a personalized approach to OSA treatment beyond CPAP lies ahead. Additional research is needed with respect to implementation and combination of therapies longitudinally, but we are enthusiastic about the future of OSA treatment based on the data presented here.
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Affiliation(s)
- Brandon Nokes
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of California, San Diego, La Jolla, CA, USA.,Section of Sleep Medicine, Veterans Affairs (VA) San Diego Healthcare System, La Jolla, CA, USA
| | - Jessica Cooper
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Michelle Cao
- Division of Pulmonary, Allergy, Critical Care Medicine & Division of Sleep Medicine, Stanford University, Palo Alto, CA, USA
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12
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Kato K, Morinaga R, Yokoyama T, Fushuku S, Wakai J, Nakamuta N, Yamamoto Y. Effects of CO 2 on time-dependent changes in cardiorespiratory functions under sustained hypoxia. Respir Physiol Neurobiol 2022; 300:103886. [PMID: 35296417 DOI: 10.1016/j.resp.2022.103886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/16/2022] [Accepted: 03/09/2022] [Indexed: 11/18/2022]
Abstract
Hypercapnia in addition to hypoxia affects the mammalian cardiorespiratory system and has been suggested to exert its effects on cardiorespiratory function by slightly different mechanisms to hypoxia. In the present study, we examined cardiorespiratory changes in urethane-anesthetized rats under hypocapnic (Hypo, 10% O2), isocapnic (Iso, 10% O2 and 4% CO2), and hypercapnic (Hyper, 10% O2 and 8% CO2) hypoxia for 2 h to clarify the effects of CO2 on sustained hypoxia-induced cardiorespiratory responses. Respiratory frequency increased the most in Hypo and tidal volume in Hyper. Minute ventilation, a product of respiratory frequency and tidal volume, increased the most in the latter group. Regarding cardiovascular variables during the hypoxic exposure period, heart rate and mean blood pressure both markedly decreased in Hypo. However, decreases in these parameters were small in Iso, and both increased over the pre-exposure level in Hyper. The present results suggest that CO2 interferes with the hypoxia-activated neural pathway via another pathway under sustained exposure to hypoxia.
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Affiliation(s)
- Kouki Kato
- Center for Laboratory Animal Science, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Ryosuke Morinaga
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, 2-1-1-1 Midorigaoka Higashi, Asahikawa, Hokkaido 078-8510, Japan
| | - Takuya Yokoyama
- Department of Anatomy (Cell Biology), Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan
| | - Seigo Fushuku
- Center for Laboratory Animal Science, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Jun Wakai
- Department of Laboratory Animal Medicine, Institute for Biomedical Sciences, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate 020-8550, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate 020-8550, Japan.
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13
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Hirsch D, Kohl A, Wang Y, Sela-Donenfeld D. Axonal Projection Patterns of the Dorsal Interneuron Populations in the Embryonic Hindbrain. Front Neuroanat 2022; 15:793161. [PMID: 35002640 PMCID: PMC8738170 DOI: 10.3389/fnana.2021.793161] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Unraveling the inner workings of neural circuits entails understanding the cellular origin and axonal pathfinding of various neuronal groups during development. In the embryonic hindbrain, different subtypes of dorsal interneurons (dINs) evolve along the dorsal-ventral (DV) axis of rhombomeres and are imperative for the assembly of central brainstem circuits. dINs are divided into two classes, class A and class B, each containing four neuronal subgroups (dA1-4 and dB1-4) that are born in well-defined DV positions. While all interneurons belonging to class A express the transcription factor Olig3 and become excitatory, all class B interneurons express the transcription factor Lbx1 but are diverse in their excitatory or inhibitory fate. Moreover, within every class, each interneuron subtype displays its own specification genes and axonal projection patterns which are required to govern the stage-by-stage assembly of their connectivity toward their target sites. Remarkably, despite the similar genetic landmark of each dINs subgroup along the anterior-posterior (AP) axis of the hindbrain, genetic fate maps of some dA/dB neuronal subtypes uncovered their contribution to different nuclei centers in relation to their rhombomeric origin. Thus, DV and AP positional information has to be orchestrated in each dA/dB subpopulation to form distinct neuronal circuits in the hindbrain. Over the span of several decades, different axonal routes have been well-documented to dynamically emerge and grow throughout the hindbrain DV and AP positions. Yet, the genetic link between these distinct axonal bundles and their neuronal origin is not fully clear. In this study, we reviewed the available data regarding the association between the specification of early-born dorsal interneuron subpopulations in the hindbrain and their axonal circuitry development and fate, as well as the present existing knowledge on molecular effectors underlying the process of axonal growth.
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Affiliation(s)
- Dana Hirsch
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.,Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Ayelet Kohl
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yuan Wang
- Department of Biomedical Sciences, Program in Neuroscience, College of Medicine, Florida State University, Tallahassee, FL, United States
| | - Dalit Sela-Donenfeld
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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14
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Smith JC. Respiratory rhythm and pattern generation: Brainstem cellular and circuit mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:1-35. [PMID: 35965022 DOI: 10.1016/b978-0-323-91534-2.00004-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Breathing movements in mammals are driven by rhythmic neural activity automatically generated within spatially and functionally organized brainstem neural circuits comprising the respiratory central pattern generator (CPG). This chapter reviews up-to-date experimental information and theoretical studies of the cellular and circuit mechanisms of respiratory rhythm and pattern generation operating within critical components of this CPG in the lower brainstem. Over the past several decades, there have been substantial advances in delineating the spatial architecture of essential medullary regions and their regional cellular and circuit properties required to understand rhythm and pattern generation mechanisms. A fundamental concept is that the circuits in these regions have rhythm-generating capabilities at multiple cellular and circuit organization levels. The regional cellular properties, circuit organization, and control mechanisms allow flexible expression of neural activity patterns for a repertoire of respiratory behaviors under various physiologic conditions that are dictated by requirements for homeostatic regulation and behavioral integration. Many mechanistic insights have been provided by computational modeling studies driven by experimental results and have advanced understanding in the field. These conceptual and theoretical developments are discussed.
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Affiliation(s)
- Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
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15
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Zhu S, Hu X, Bennett S, Charlesworth O, Qin S, Mai Y, Dou H, Xu J. Galanin family peptides: Molecular structure, expression and roles in the neuroendocrine axis and in the spinal cord. Front Endocrinol (Lausanne) 2022; 13:1019943. [PMID: 36561569 PMCID: PMC9764007 DOI: 10.3389/fendo.2022.1019943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022] Open
Abstract
Galanin is a neurohormone as well as a neurotransmitter and plays versatile physiological roles for the neuroendocrine axis, such as regulating food intake, insulin level and somatostatin release. It is expressed in the central nervous system, including hypothalamus, pituitary, and the spinal cord, and colocalises with other neuronal peptides within neurons. Structural analyses reveal that the human galanin precursor is 104 amino acid (aa) residues in length, consisting of a mature galanin peptide (aa 33-62), and galanin message-associated peptide (GMAP; aa 63-104) at the C-terminus. GMAP appears to exhibit distinctive biological effects on anti-fungal activity and the spinal flexor reflex. Galanin-like peptide (GALP) has a similar structure to galanin and acts as a hypothalamic neuropeptide to mediate metabolism and reproduction, food intake, and body weight. Alarin, a differentially spliced variant of GALP, is specifically involved in vasoactive effect in the skin and ganglionic differentiation in neuroblastic tumors. Dysregulation of galanin, GALP and alarin has been implicated in various neuroendocrine conditions such as nociception, Alzheimer's disease, seizures, eating disorders, alcoholism, diabetes, and spinal cord conditions. Further delineation of the common and distinctive effects and mechanisms of various types of galanin family proteins could facilitate the design of therapeutic approaches for neuroendocrine diseases and spinal cord injury.
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Affiliation(s)
- Sipin Zhu
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
- Molecular Lab, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Xiaoyong Hu
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Guangdong Research Institute of Petrochemical and Fine Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, China
| | - Samuel Bennett
- Molecular Lab, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Oscar Charlesworth
- Molecular Lab, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Shengnan Qin
- Molecular Lab, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Yuliang Mai
- Guangdong Provincial Key Laboratory of Industrial Surfactant, Guangdong Research Institute of Petrochemical and Fine Chemical Engineering, Guangdong Academy of Sciences, Guangzhou, China
| | - Haicheng Dou
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jiake Xu
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
- Molecular Lab, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
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16
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Abstract
Brain PCO2 is sensed primarily via changes in [H+]. Small pH changes are detected in the medulla oblongata and trigger breathing adjustments that help maintain arterial PCO2 constant. Larger perturbations of brain CO2/H+, possibly also sensed elsewhere in the CNS, elicit arousal, dyspnea, and stress, and cause additional breathing modifications. The retrotrapezoid nucleus (RTN), a rostral medullary cluster of glutamatergic neurons identified by coexpression of Phoxb and Nmb transcripts, is the lynchpin of the central respiratory chemoreflex. RTN regulates breathing frequency, inspiratory amplitude, and active expiration. It is exquisitely responsive to acidosis in vivo and maintains breathing autorhythmicity during quiet waking, slow-wave sleep, and anesthesia. The RTN response to [H+] is partly an intrinsic neuronal property mediated by proton sensors TASK-2 and GPR4 and partly a paracrine effect mediated by astrocytes and the vasculature. The RTN also receives myriad excitatory or inhibitory synaptic inputs including from [H+]-responsive neurons (e.g., serotonergic). RTN is silenced by moderate hypoxia. RTN inactivity (periodic or sustained) contributes to periodic breathing and, likely, to central sleep apnea. RTN development relies on transcription factors Egr2, Phox2b, Lbx1, and Atoh1. PHOX2B mutations cause congenital central hypoventilation syndrome; they impair RTN development and consequently the central respiratory chemoreflex.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States.
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States
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17
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Patodia S, Somani A, Thom M. Review: Neuropathology findings in autonomic brain regions in SUDEP and future research directions. Auton Neurosci 2021; 235:102862. [PMID: 34411885 PMCID: PMC8455454 DOI: 10.1016/j.autneu.2021.102862] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/16/2021] [Accepted: 07/24/2021] [Indexed: 12/21/2022]
Abstract
Autonomic dysfunction is implicated from clinical, neuroimaging and experimental studies in sudden and unexpected death in epilepsy (SUDEP). Neuropathological analysis in SUDEP series enable exploration of acquired, seizure-related cellular adaptations in autonomic and brainstem autonomic centres of relevance to dysfunction in the peri-ictal period. Alterations in SUDEP compared to control groups have been identified in the ventrolateral medulla, amygdala, hippocampus and central autonomic regions. These involve neuropeptidergic, serotonergic and adenosine systems, as well as specific regional astroglial and microglial populations, as potential neuronal modulators, orchestrating autonomic dysfunction. Future research studies need to extend to clinically and genetically characterized epilepsies, to explore if common or distinct pathways of autonomic dysfunction mediate SUDEP. The ultimate objective of SUDEP research is the identification of disease biomarkers for at risk patients, to improve post-mortem recognition and disease categorisation, but ultimately, for exposing potential treatment targets of pharmacologically modifiable and reversible cellular alterations.
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Affiliation(s)
- Smriti Patodia
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Alyma Somani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
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18
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Palkovic B, Marchenko V, Zuperku EJ, Stuth EAE, Stucke AG. Multi-Level Regulation of Opioid-Induced Respiratory Depression. Physiology (Bethesda) 2021; 35:391-404. [PMID: 33052772 DOI: 10.1152/physiol.00015.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Opioids depress minute ventilation primarily by reducing respiratory rate. This results from direct effects on the preBötzinger Complex as well as from depression of the Parabrachial/Kölliker-Fuse Complex, which provides excitatory drive to preBötzinger Complex neurons mediating respiratory phase-switch. Opioids also depress awake drive from the forebrain and chemodrive.
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Affiliation(s)
- Barbara Palkovic
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Faculty of Medicine, University of Osijek, Osijek, Croatia
| | | | - Edward J Zuperku
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Zablocki VA Medical Center, Milwaukee, Wisconsin
| | - Eckehard A E Stuth
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Astrid G Stucke
- Medical College of Wisconsin, Milwaukee, Wisconsin.,Children's Hospital of Wisconsin, Milwaukee, Wisconsin
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19
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Oliveira LM, Baertsch NA, Moreira TS, Ramirez JM, Takakura AC. Unraveling the Mechanisms Underlying Irregularities in Inspiratory Rhythm Generation in a Mouse Model of Parkinson's Disease. J Neurosci 2021; 41:4732-4747. [PMID: 33863785 PMCID: PMC8260248 DOI: 10.1523/jneurosci.2114-20.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 12/15/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder anatomically characterized by a progressive loss of dopaminergic neurons in the substantia nigra compacta (SNpc). Much less known, yet clinically very important, are the detrimental effects on breathing associated with this disease. Consistent with the human pathophysiology, the 6-hydroxydopamine hydrochloride (6-OHDA) rodent model of PD shows reduced respiratory frequency (fR) and NK1r-immunoreactivity in the pre-Bötzinger complex (preBötC) and PHOX2B+ neurons in the retrotrapezoid nucleus (RTN). To unravel mechanisms that underlie bradypnea in PD, we employed a transgenic approach to label or stimulate specific neuron populations in various respiratory-related brainstem regions. PD mice were characterized by a pronounced decreased number of putatively rhythmically active excitatory neurons in the preBötC and adjacent ventral respiratory column (VRC). Specifically, the number of Dbx1 and Vglut2 neurons was reduced by 47.6% and 17.3%, respectively. By contrast, inhibitory Vgat+ neurons in the VRC, as well as neurons in other respiratory-related brainstem regions, showed relatively minimal or no signs of neuronal loss. Consistent with these anatomic observations, optogenetic experiments identified deficits in respiratory function that were specific to manipulations of excitatory (Dbx1/Vglut2) neurons in the preBötC. We conclude that the decreased number of this critical population of respiratory neurons is an important contributor to the development of irregularities in inspiratory rhythm generation in this mouse model of PD.SIGNIFICANCE STATEMENT We found a decreased number of a specific population of medullary neurons which contributes to breathing abnormalities in a mouse model of Parkinson's disease (PD).
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Affiliation(s)
- Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo 05508, Brazil
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington 98101
| | - Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington 98101
- Department of Pediatrics, University of Washington, Seattle, Washington 98101
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo 05508, Brazil
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington 98101
- Department of Neurological Surgery, University of Washington, Seattle, Washington 98101
- Department of Pediatrics, University of Washington, Seattle, Washington 98101
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo 05508, Brazil
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20
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Levy J, Droz-Bartholet F, Achour M, Facchinetti P, Parratte B, Giuliano F. Parafacial neurons in the human brainstem express specific markers for neurons of the retrotrapezoid nucleus. J Comp Neurol 2021; 529:3313-3320. [PMID: 34008871 DOI: 10.1002/cne.25191] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/08/2021] [Accepted: 05/13/2021] [Indexed: 11/06/2022]
Abstract
The retrotrapezoid nucleus (RTN) is a hub for respiratory chemoregulation in the mammal brainstem that integrates chemosensory information from peripheral sites and central relays. Chemosensitive neurons of the RTN express specific genetic and molecular determinants, which have been used to identify RTN precise location within the brainstem of rodents and nonhuman primates. Based on a comparative approach, we hypothesized that among mammals, neurons exhibiting the same specific molecular and genetic signature would have the same function. The co-expression of preprogalanin (PPGAL) and SLC17A6 (VGluT2) mRNAs with duplex in situ hybridization has been studied in formalin fixed paraffin-embedded postmortem human brainstems. Two specimens were processed and analyzed in line with RTN descriptions in adult rats and macaques. Double-labeled PPGAL+/SLC17A6+ neurons were only identified in the parafacial region of the brainstem. These neurons were found surrounding the nucleus of the facial nerve, located ventrally to the nucleus VII on caudal sections, and slightly more dorsally on rostral sections. The expression of neuromedin B (NMB) mRNA as a single marker of chemosensitive RTN neurons has not been confirmed in humans. The location of the RTN in human adults is provided. This should help to develop investigation tools combining anatomic high-resolution imaging and respiratory functional investigations to explore the pathogenic role of the RTN in congenital or acquired neurodegenerative diseases.
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Affiliation(s)
- Jonathan Levy
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France.,Service de Médecine Physique et de Réadaptation - APHP, Hôpital Raymond Poincaré, Garches, France.,Fondation Garches - Hôpital Raymond Poincaré, Garches, France
| | - François Droz-Bartholet
- Laboratoire d'Anatomie - Faculté de Médecine de Besançon, Université de Franche-Comté, Besançon, France.,Service de Médecine Physique et de Réadaptation - CHRU Jean Minjoz, Besançon, France
| | - Melyna Achour
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France
| | - Patricia Facchinetti
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France
| | - Bernard Parratte
- Laboratoire d'Anatomie - Faculté de Médecine de Besançon, Université de Franche-Comté, Besançon, France.,Service de Médecine Physique et de Réadaptation - CHRU Jean Minjoz, Besançon, France
| | - François Giuliano
- UMR 1179 (Inserm-UVSQ) Neuromuscular Handicap - UFR des sciences de la Santé Simone Veil, Université de Versailles St. Quentin, Montigny-le-Bretonneux, Paris Saclay campus, France.,Service de Médecine Physique et de Réadaptation - APHP, Hôpital Raymond Poincaré, Garches, France
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21
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Takakura AC, Malheiros-Lima MR, Moreira TS. Excitatory and inhibitory modulation of parafacial respiratory neurons in the control of active expiration. Respir Physiol Neurobiol 2021; 289:103657. [PMID: 33781931 DOI: 10.1016/j.resp.2021.103657] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/22/2021] [Accepted: 03/21/2021] [Indexed: 01/21/2023]
Abstract
In order to increase ventilation, the respiratory system engages active expiration through recruitment of abdominal muscles. Here, we reviewed the new advances in the modulation of parafacial respiratory (pF) region to trigger active expiration. In addition, we also made a comprehensive discussion of experiments indicating that the lateral aspect of the pF (pFL) is anatomically and functionally distinct from the adjacent and partially overlapping chemosensitive neurons of the ventral aspect of the pF (pFV) also named the retrotrapezoid nucleus. Recent evidence suggest a complex network responsible for the generation of active expiration and neuromodulatory systems that influence its activity. The activity of the pFL is tonically inhibited by inhibitory inputs and also receives excitatory inputs from chemoreceptors (central x peripheral) as well as from catecholaminergic C1 neurons. Therefore, the modulatory inputs and the physiological conditions under which these mechanisms are used to recruit active expiration and increase ventilation need further investigation.
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Affiliation(s)
- Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000, São Paulo, SP, Brazil.
| | - Milene R Malheiros-Lima
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000, São Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000, São Paulo, SP, Brazil.
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22
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Abbott SBG, Souza GMPR. Chemoreceptor mechanisms regulating CO 2 -induced arousal from sleep. J Physiol 2021; 599:2559-2571. [PMID: 33759184 DOI: 10.1113/jp281305] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/16/2021] [Indexed: 12/24/2022] Open
Abstract
Arousal from sleep in response to CO2 is a life-preserving reflex that enhances ventilatory drive and facilitates behavioural adaptations to restore eupnoeic breathing. Recurrent activation of the CO2 -arousal reflex is associated with sleep disruption in obstructive sleep apnoea. In this review we examine the role of chemoreceptors in the carotid bodies, the retrotrapezoid nucleus and serotonergic neurons in the dorsal raphe in the CO2 -arousal reflex. We also provide an overview of the supra-medullary structures that mediate CO2 -induced arousal. We propose a framework for the CO2 -arousal reflex in which the activity of the chemoreceptors converges in the parabrachial nucleus to trigger cortical arousal.
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Affiliation(s)
- Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 29903, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 29903, USA
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23
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Alzate-Correa D, Mei-Ling Liu J, Jones M, Silva TM, Alves MJ, Burke E, Zuñiga J, Kaya B, Zaza G, Aslan MT, Blackburn J, Shimada MY, Fernandes-Junior SA, Baer LA, Stanford KI, Kempton A, Smith S, Szujewski CC, Silbaugh A, Viemari JC, Takakura AC, Garcia AJ, Moreira TS, Czeisler CM, Otero JJ. Neonatal apneic phenotype in a murine congenital central hypoventilation syndrome model is induced through non-cell autonomous developmental mechanisms. Brain Pathol 2020; 31:84-102. [PMID: 32654284 PMCID: PMC7881415 DOI: 10.1111/bpa.12877] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 05/10/2020] [Accepted: 06/11/2020] [Indexed: 12/19/2022] Open
Abstract
Congenital central hypoventilation syndrome (CCHS) represents a rare genetic disorder usually caused by mutations in the homeodomain transcription factor PHOX2B. Some CCHS patients suffer mainly from deficiencies in CO2 and/or O2 respiratory chemoreflex, whereas other patients present with full apnea shortly after birth. Our goal was to identify the neuropathological mechanisms of apneic presentations in CCHS. In the developing murine neuroepithelium, Phox2b is expressed in three discrete progenitor domains across the dorsal-ventral axis, with different domains responsible for producing unique autonomic or visceral motor neurons. Restricting the expression of mutant Phox2b to the ventral visceral motor neuron domain induces marked newborn apnea together with a significant loss of visceral motor neurons, RTN ablation, and preBötzinger complex dysfunction. This finding suggests that the observed apnea develops through non-cell autonomous developmental mechanisms. Mutant Phox2b expression in dorsal rhombencephalic neurons did not generate significant respiratory dysfunction, but did result in subtle metabolic thermoregulatory deficiencies. We confirm the expression of a novel murine Phox2b splice variant which shares exons 1 and 2 with the more widely studied Phox2b splice variant, but which differs in exon 3 where most CCHS mutations occur. We also show that mutant Phox2b expression in the visceral motor neuron progenitor domain increases cell proliferation at the expense of visceral motor neuron development. We propose that visceral motor neurons may function as organizers of brainstem respiratory neuron development, and that disruptions in their development result in secondary/non-cell autonomous maldevelopment of key brainstem respiratory neurons.
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Affiliation(s)
- Diego Alzate-Correa
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jillian Mei-Ling Liu
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Mikayla Jones
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Talita M Silva
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Michele Joana Alves
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Elizabeth Burke
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jessica Zuñiga
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Behiye Kaya
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Giuliana Zaza
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Mehmet Tahir Aslan
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jessica Blackburn
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Marina Y Shimada
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Silvio A Fernandes-Junior
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Lisa A Baer
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Kristin I Stanford
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Amber Kempton
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Sakima Smith
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Caroline C Szujewski
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Committee on Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Abby Silbaugh
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Committee on Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Jean-Charles Viemari
- P3M Team, Institut de Neurosciences de la Timone, UMR 7289 AMU-CNRS, Marseille, France
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Alfredo J Garcia
- Institute for Integrative Physiology, Grossman Institute for Neuroscience Quantitative Biology and Human Behavior, The Committee on Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Catherine M Czeisler
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - José J Otero
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
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24
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Venner A, Todd WD, Fraigne J, Bowrey H, Eban-Rothschild A, Kaur S, Anaclet C. Newly identified sleep-wake and circadian circuits as potential therapeutic targets. Sleep 2020; 42:5306564. [PMID: 30722061 DOI: 10.1093/sleep/zsz023] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/25/2019] [Indexed: 02/06/2023] Open
Abstract
Optogenetics and chemogenetics are powerful tools, allowing the specific activation or inhibition of targeted neuronal subpopulations. Application of these techniques to sleep and circadian research has resulted in the unveiling of several neuronal populations that are involved in sleep-wake control, and allowed a comprehensive interrogation of the circuitry through which these nodes are coordinated to orchestrate the sleep-wake cycle. In this review, we discuss six recently described sleep-wake and circadian circuits that show promise as therapeutic targets for sleep medicine. The parafacial zone (PZ) and the ventral tegmental area (VTA) are potential druggable targets for the treatment of insomnia. The brainstem circuit underlying rapid eye movement sleep behavior disorder (RBD) offers new possibilities for treating RBD and neurodegenerative synucleinopathies, whereas the parabrachial nucleus, as a nexus linking arousal state control and breathing, is a promising target for developing treatments for sleep apnea. Therapies that act upon the hypothalamic circuitry underlying the circadian regulation of aggression or the photic regulation of arousal and mood pathway carry enormous potential for helping to reduce the socioeconomic burden of neuropsychiatric and neurodegenerative disorders on society. Intriguingly, the development of chemogenetics as a therapeutic strategy is now well underway and such an approach has the capacity to lead to more focused and less invasive therapies for treating sleep-wake disorders and related comorbidities.
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Affiliation(s)
- Anne Venner
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - William D Todd
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Jimmy Fraigne
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Hannah Bowrey
- Department of Psychiatry, Rutgers Biomedical Health Sciences, Rutgers University, Newark, NJ.,Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
| | | | - Satvinder Kaur
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Christelle Anaclet
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, NeuroNexus Institute, Graduate Program in Neuroscience - Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA
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25
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Breathing under Anesthesia: A Key Role for the Retrotrapezoid Nucleus Revealed by Conditional Phox2b Mutant Mice. Anesthesiology 2020; 130:995-1006. [PMID: 31091200 DOI: 10.1097/aln.0000000000002675] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Optimal management of anesthesia-induced respiratory depression requires identification of the neural pathways that are most effective in maintaining breathing during anesthesia. Lesion studies point to the brainstem retrotrapezoid nucleus. We therefore examined the respiratory effects of common anesthetic/analgesic agents in mice with selective genetic loss of retrotrapezoid nucleus neurons (Phox2b mice, hereafter designated "mutants"). METHODS All mice received intraperitoneal ketamine doses ranging from 100 mg/kg at postnatal day (P) 8 to 250 mg/kg at P60 to P62. Anesthesia effects in P8 and P14 to P16 mice were then analyzed by administering propofol (100 and 150 mg/kg at P8 and P14 to P16, respectively) and fentanyl at an anesthetic dose (1 mg/kg at P8 and P14 to P16). RESULTS Most mutant mice died of respiratory arrest within 13 min of ketamine injection at P8 (12 of 13, 92% vs. 0 of 8, 0% wild type; Fisher exact test, P < 0.001) and P14 to P16 (32 of 42, 76% vs. 0 of 59, 0% wild type; P < 0.001). Cardiac activity continued after terminal apnea, and mortality was prevented by mechanical ventilation, supporting respiratory arrest as the cause of death in the mutants. Ketamine-induced mortality in mutants compared to wild types was confirmed at P29 to P31 (24 of 36, 67% vs. 9 of 45, 20%; P < 0.001) and P60 to P62 (8 of 19, 42% vs. 0 of 12, 0%; P = 0.011). Anesthesia-induced mortality in mutants compared to wild types was also observed with propofol at P8 (7 of 7, 100% vs. 0 of 17,7/7, 100% vs. 0/17, 0%; P < 0.001) and P14 to P16 (8 of 10, 80% vs. 0 of 10, 0%; P < 0.001) and with fentanyl at P8 (15 of 16, 94% vs. 0 of 13, 0%; P < 0.001) and P14 to P16 (5 of 7, 71% vs. 0 of 11, 0%; P = 0.002). CONCLUSIONS Ketamine, propofol, and fentanyl caused death by respiratory arrest in most mice with selective loss of retrotrapezoid nucleus neurons, in doses that were safe in their wild type littermates. The retrotrapezoid nucleus is critical to sustain breathing during deep anesthesia and may prove to be a pharmacologic target for this purpose.
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26
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Endogenous glutamatergic inputs to the Parabrachial Nucleus/Kölliker-Fuse Complex determine respiratory rate. Respir Physiol Neurobiol 2020; 277:103401. [PMID: 32036030 DOI: 10.1016/j.resp.2020.103401] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/06/2020] [Accepted: 01/28/2020] [Indexed: 01/10/2023]
Abstract
The Kölliker-Fuse Nucleus (KF) has been widely investigated for its contribution to "inspiratory off-switch" while more recent studies showed that activation of the Parabrachial Nucleus (PBN) shortened expiratory duration. This study used an adult, in vivo, decerebrate rabbit model to delineate the contribution of each site to inspiratory and expiratory duration through sequential block of glutamatergic excitation with the receptor antagonists 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) and d(-)-2-amino-5-phosphonopentanoic acid (AP5). Glutamatergic disfacilitation caused large increases in inspiratory and expiratory duration and minor decrease in peak phrenic activity (PPA). Hypoxia only partially reversed respiratory rate depression but PPA was increased to >200 % of control. The contribution of PBN activity to inspiratory and expiratory duration was equal while block of the KF affected inspiratory duration more than expiratory. We conclude that in the in vivo preparation respiratory rate greatly depends on PBN/KF activity, which contributes to the "inspiratory on- "and "off-switch", but is of minor importance for the magnitude of phrenic motor output.
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27
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Dereli AS, Yaseen Z, Carrive P, Kumar NN. Adaptation of Respiratory-Related Brain Regions to Long-Term Hypercapnia: Focus on Neuropeptides in the RTN. Front Neurosci 2019; 13:1343. [PMID: 31920508 PMCID: PMC6923677 DOI: 10.3389/fnins.2019.01343] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/28/2019] [Indexed: 12/21/2022] Open
Abstract
Long-term hypercapnia is associated with respiratory conditions including obstructive sleep apnea, chronic obstructive pulmonary disease and obesity hypoventilation syndrome. Animal studies have demonstrated an initial (within hours) increase in ventilatory drive followed by a decrease in this response over the long-term (days–weeks) in response hypercapnia. Little is known about whether changes in the central respiratory chemoreflex are involved. Here we investigated whether central respiratory chemoreceptor neurons of the retrotrapezoid nucleus (RTN), which project to the respiratory pattern generator within the ventral respiratory column (VRC) have a role in the mechanism of neuroplasticity associated with long-term hypercapnia. Adult male C57BL/6 mice (n = 5/group) were used. Our aims were (1) to determine if galanin, neuromedin B and gastrin-releasing peptide gene expression is altered in the RTN after long-term hypercapnia. This was achieved using qPCR to measure mRNA expression changes of neuropeptides in the RTN after short-term hypercapnia (6 or 8 h, 5 or 8% CO2) or long-term hypercapnia exposure (10 day, 5 or 8% CO2), (2) in the mouse brainstem, to determine the distribution of preprogalanin in chemoreceptors, and the co-occurrence of the galanin receptor 1 (GalR1:Gi-coupled receptor) with inhibitory GlyT2 ventral respiratory column neurons using in situ hybridization (ISH) to better characterize galaninergic RTN-VRC circuitry, (3) to investigate whether long-term hypercapnia causes changes to recruitment (detected by cFos immunohistochemistry) of respiratory related neural populations including the RTN neurons and their galaninergic subset, in vivo. Collectively, we found that hypercapnia decreases neuropeptide expression in the RTN in the short-term and has the opposite effect over the long-term. Following long term hypercapnia, the number of RTN galanin neurons remains unchanged, and their responsiveness to acute chemoreflex is sustained; in contrast, we identified multiple respiratory related sites that exhibit blunted chemoreflex activation. GalR1 was distributed in 11% of preBötC and 30% of BötC glycinergic neurons. Our working hypothesis is that during long-term hypercapnia, galanin co-release from RTN neurons may counterbalance glutamatergic inputs to respiratory centers to downscale energetically wasteful hyperventilation, thereby having a role in neuroplasticity by contributing to a decrease in ventilation, through the inhibitory effects of galanin.
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Affiliation(s)
- Ayse Sumeyra Dereli
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Zarwa Yaseen
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Pascal Carrive
- Department of Anatomy, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Natasha N Kumar
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
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28
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Participation of GABA B Receptors of Parafacial Respiratory Group in the Regulation of Respiration in Rats. Bull Exp Biol Med 2019; 168:24-27. [PMID: 31745683 DOI: 10.1007/s10517-019-04637-3] [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: 04/02/2019] [Indexed: 10/25/2022]
Abstract
The respiratory effects of microinjections of baclofen and 2-hydroxysaclofen into the parafacial respiratory group were studied in experiments on rats. It was shown that activation of GABAB receptors of the parafacial respiratory group suppressed external respiration due to a decrease in the tidal volume and inspiratory flow rate. In parallel, we observed a decrease in the amplitude and an increase in the duration of inspiratory bursts of the diaphragm. Injection of GABAB receptor blocker into the parafacial respiratory group increased pulmonary ventilation due to an increase in volumetric parameters of the inspiratory phase. This effect was accompanied by prolongation of expiration and lengthening of the intervals between the inspiratory bursts of the diaphragm. These results suggest that GABAB receptors of the parafacial respiratory group are an important element of the central mechanisms regulating the volumetric respiratory parameters and are involved in the regulation of the phases of the respiratory cycle.
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29
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Contribution of the Retrotrapezoid Nucleus and Carotid Bodies to Hypercapnia- and Hypoxia-induced Arousal from Sleep. J Neurosci 2019; 39:9725-9737. [PMID: 31641048 DOI: 10.1523/jneurosci.1268-19.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [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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30
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Guyenet PG, Stornetta RL, Souza GMPR, Abbott SBG, Shi Y, Bayliss DA. The Retrotrapezoid Nucleus: Central Chemoreceptor and Regulator of Breathing Automaticity. Trends Neurosci 2019; 42:807-824. [PMID: 31635852 DOI: 10.1016/j.tins.2019.09.002] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/28/2019] [Accepted: 09/05/2019] [Indexed: 12/15/2022]
Abstract
The ventral surface of the rostral medulla oblongata has been suspected since the 1960s to harbor central respiratory chemoreceptors [i.e., acid-activated neurons that regulate breathing to maintain a constant arterial PCO2 (PaCO2)]. The key neurons, a.k.a. the retrotrapezoid nucleus (RTN), have now been identified. In this review we describe their transcriptome, developmental lineage, and anatomical projections. We also review their contribution to CO2 homeostasis and to the regulation of breathing automaticity during sleep and wake. Finally, we discuss several mechanisms that contribute to the activation of RTN neurons by CO2in vivo: cell-autonomous effects of protons; paracrine effects of pH mediated by surrounding astrocytes and blood vessels; and excitatory inputs from other CO2-responsive CNS neurons.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA.
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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31
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Abstract
Breathing is a well-described, vital and surprisingly complex behaviour, with behavioural and physiological outputs that are easy to directly measure. Key neural elements for generating breathing pattern are distinct, compact and form a network amenable to detailed interrogation, promising the imminent discovery of molecular, cellular, synaptic and network mechanisms that give rise to the behaviour. Coupled oscillatory microcircuits make up the rhythmic core of the breathing network. Primary among these is the preBötzinger Complex (preBötC), which is composed of excitatory rhythmogenic interneurons and excitatory and inhibitory pattern-forming interneurons that together produce the essential periodic drive for inspiration. The preBötC coordinates all phases of the breathing cycle, coordinates breathing with orofacial behaviours and strongly influences, and is influenced by, emotion and cognition. Here, we review progress towards cracking the inner workings of this vital core.
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32
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Bolea I, Gella A, Sanz E, Prada-Dacasa P, Menardy F, Bard AM, Machuca-Márquez P, Eraso-Pichot A, Mòdol-Caballero G, Navarro X, Kalume F, Quintana A. Defined neuronal populations drive fatal phenotype in a mouse model of Leigh syndrome. eLife 2019; 8:47163. [PMID: 31403401 PMCID: PMC6731060 DOI: 10.7554/elife.47163] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/11/2019] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial deficits in energy production cause untreatable and fatal pathologies known as mitochondrial disease (MD). Central nervous system affectation is critical in Leigh Syndrome (LS), a common MD presentation, leading to motor and respiratory deficits, seizures and premature death. However, only specific neuronal populations are affected. Furthermore, their molecular identity and their contribution to the disease remains unknown. Here, using a mouse model of LS lacking the mitochondrial complex I subunit Ndufs4, we dissect the critical role of genetically-defined neuronal populations in LS progression. Ndufs4 inactivation in Vglut2-expressing glutamatergic neurons leads to decreased neuronal firing, brainstem inflammation, motor and respiratory deficits, and early death. In contrast, Ndufs4 deletion in GABAergic neurons causes basal ganglia inflammation without motor or respiratory involvement, but accompanied by hypothermia and severe epileptic seizures preceding death. These results provide novel insight in the cell type-specific contribution to the pathology, dissecting the underlying cellular mechanisms of MD.
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Affiliation(s)
- Irene Bolea
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, United States.,Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Alejandro Gella
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Elisenda Sanz
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Patricia Prada-Dacasa
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Fabien Menardy
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Angela M Bard
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | | | - Abel Eraso-Pichot
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Guillem Mòdol-Caballero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Xavier Navarro
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Franck Kalume
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Neurological Surgery, University of Washington, Seattle, United States.,Department of Pharmacology, University of Washington, Seattle, United States
| | - Albert Quintana
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, United States.,Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Pediatrics, University of Washington, Seattle, United States
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33
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Patodia S, Somani A, O'Hare M, Venkateswaran R, Liu J, Michalak Z, Ellis M, Scheffer IE, Diehl B, Sisodiya SM, Thom M. The ventrolateral medulla and medullary raphe in sudden unexpected death in epilepsy. Brain 2019; 141:1719-1733. [PMID: 29608654 PMCID: PMC5972615 DOI: 10.1093/brain/awy078] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/01/2018] [Indexed: 11/14/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a leading cause of premature death in patients with epilepsy. One hypothesis proposes that sudden death is mediated by post-ictal central respiratory depression, which could relate to underlying pathology in key respiratory nuclei and/or their neuromodulators. Our aim was to investigate neuronal populations in the ventrolateral medulla (which includes the putative human pre-Bötzinger complex) and the medullary raphe. Forty brainstems were studied comprising four groups: 14 SUDEP, six epilepsy controls, seven Dravet syndrome cases and 13 non-epilepsy controls. Serial sections through the medulla (from obex 1 to 10 mm) were stained for Nissl, somatostatin, neurokinin 1 receptor (for pre-Bötzinger complex neurons) and galanin, tryptophan hydroxylase and serotonin transporter (neuromodulatory systems). Using stereology total neuronal number and densities, with respect to obex level, were measured. Whole slide scanning image analysis was used to quantify immunolabelling indices as well as co-localization between markers. Significant findings included reduction in somatostatin neurons and neurokinin 1 receptor labelling in the ventrolateral medulla in sudden death in epilepsy compared to controls (P < 0.05). Galanin and tryptophan hydroxylase labelling was also reduced in sudden death cases and more significantly in the ventrolateral medulla region than the raphe (P < 0.005 and P < 0.05). With serotonin transporter, reduction in labelling in cases of sudden death in epilepsy was noted only in the raphe (P ≤ 0.01); however, co-localization with tryptophan hydroxylase was significantly reduced in the ventrolateral medulla. Epilepsy controls and cases with Dravet syndrome showed less significant alterations with differences from non-epilepsy controls noted only for somatostatin in the ventrolateral medulla (P < 0.05). Variations in labelling with respect to obex level were noted of potential relevance to the rostro-caudal organization of respiratory nuclear groups, including tryptophan hydroxylase, where the greatest statistical difference noted between all epilepsy cases and controls was at obex 9-10 mm (P = 0.034), the putative level of the pre-Bötzinger complex. Furthermore, there was evidence for variation with duration of epilepsy for somatostatin and neurokinin 1 receptor. Our findings suggest alteration to neuronal populations in the medulla in SUDEP with evidence for greater reduction in neuromodulatory neuropeptidergic and mono-aminergic systems, including for galanin, and serotonin. Other nuclei need to be investigated to evaluate if this is part of more widespread brainstem pathology. Our findings could be a result of previous seizures and may represent a pathological risk factor for SUDEP through impaired respiratory homeostasis during a seizure.
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Affiliation(s)
- Smriti Patodia
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Alyma Somani
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Megan O'Hare
- Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Ranjana Venkateswaran
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Joan Liu
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Department of Biomedical Sciences, University of Westminster London W1W 6UW, UK
| | - Zuzanna Michalak
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Matthew Ellis
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine (Neurology), University of Melbourne, Victoria 3052, Australia
| | - Beate Diehl
- Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Sanjay M Sisodiya
- Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Maria Thom
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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34
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Levy J, Facchinetti P, Jan C, Achour M, Bouvier C, Brunet JF, Delzescaux T, Giuliano F. Tridimensional mapping of Phox2b expressing neurons in the brainstem of adult Macaca fascicularis and identification of the retrotrapezoid nucleus. J Comp Neurol 2019; 527:2875-2884. [PMID: 31071232 DOI: 10.1002/cne.24713] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 11/08/2022]
Abstract
Chemosensitivity is a key mechanism for the regulation of breathing in vertebrates. The retrotrapezoid nucleus is a crucial hub for respiratory chemoreception within the brainstem. It integrates chemosensory information that are both peripheral from the carotid bodies (via the nucleus of the solitary tract) and central through the direct sensing of extracellular protons. To date, the location of a genetically defined RTN has only been ascertained in rodents. We first demonstrated that Phox2b, a key determinant for the development of the visceral nervous system and branchiomotor nuclei in the brainstem including the RTN, had a similar distribution in the brainstem of adult macaques compared to adult rats. Second, based on previous description of a specific molecular signature for the RTN in rats, and on an innovative technique for duplex in situ hybridization, we identified parafacial neurons which coexpressed Phox2b and ppGal mRNAs. They were located ventrally to the nucleus of the facial nerve and extended from the caudal part of the nucleus of the superior olive to the rostral tip of the inferior olive. Using the previously described blockface technique, deformations were corrected to allow the proper alignment and stacking of digitized sections, hence providing for the first time a 3D reconstruction of the macaque brainstem, Phox2b distribution and the primate retrotrapezoid nucleus. This description should help bridging the gap between rodents and humans for the description of key respiratory structures in the brainstem.
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Affiliation(s)
- Jonathan Levy
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France.,Service de Médecine Physique et de Réadaptation-APHP, Hôpital Raymond Poincaré, Garches, France.,Fondation Garches-APHP, Hôpital Raymond Poincaré, Garches, France
| | - Patricia Facchinetti
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Caroline Jan
- Molecular Imaging Research Center (MIRCen)-Commissariat à l'Énergie Atomique (CEA), Fontenay-aux-Roses, France.,CNRS-CEA UMR9199-Neurodegenerative Diseases Laboratory, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Mélyna Achour
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Clément Bouvier
- Molecular Imaging Research Center (MIRCen)-Commissariat à l'Énergie Atomique (CEA), Fontenay-aux-Roses, France.,NEOXIA, Paris, France
| | - Jean-François Brunet
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, Paris, France
| | - Thierry Delzescaux
- Molecular Imaging Research Center (MIRCen)-Commissariat à l'Énergie Atomique (CEA), Fontenay-aux-Roses, France.,CNRS-CEA UMR9199-Neurodegenerative Diseases Laboratory, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - François Giuliano
- INSERM UMR1179-Handicap Neuromusculaire, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France.,Service de Médecine Physique et de Réadaptation-APHP, Hôpital Raymond Poincaré, Garches, France
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35
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Kaur S, Saper CB. Neural Circuitry Underlying Waking Up to Hypercapnia. Front Neurosci 2019; 13:401. [PMID: 31080401 PMCID: PMC6497806 DOI: 10.3389/fnins.2019.00401] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 04/08/2019] [Indexed: 12/13/2022] Open
Abstract
Obstructive sleep apnea is a sleep and breathing disorder, in which, patients suffer from cycles of atonia of airway dilator muscles during sleep, resulting in airway collapse, followed by brief arousals that help re-establish the airway patency. These repetitive arousals which can occur hundreds of times during the course of a night are the cause of the sleep-disruption, which in turn causes cognitive impairment as well as cardiovascular and metabolic morbidities. To prevent this potential outcome, it is important to target preventing the arousal from sleep while preserving or augmenting the increase in respiratory drive that reinitiates breathing, but will require understanding of the neural circuits that regulate the cortical and respiratory responses to apnea. The parabrachial nucleus (PB) is located in rostral pons. It receives chemosensory information from medullary nuclei that sense increase in CO2 (hypercapnia), decrease in O2 (hypoxia) and mechanosensory inputs from airway negative pressure during apneas. The PB area also exerts powerful control over cortical arousal and respiration, and therefore, is an excellent candidate for mediating the EEG arousal and restoration of the airway during sleep apneas. Using various genetic tools, we dissected the neuronal sub-types responsible for relaying the stimulus for cortical arousal to forebrain arousal circuits. The present review will focus on the circuitries that regulate waking-up from sleep in response to hypercapnia.
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Affiliation(s)
- Satvinder Kaur
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Clifford B Saper
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
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36
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Cook-Snyder DR, Miller JR, Navarrete-Opazo AA, Callison JJ, Peterson RC, Hopp FA, Stuth EAE, Zuperku EJ, Stucke AG. The contribution of endogenous glutamatergic input in the ventral respiratory column to respiratory rhythm. Respir Physiol Neurobiol 2019; 260:37-52. [PMID: 30502519 PMCID: PMC6397772 DOI: 10.1016/j.resp.2018.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/22/2018] [Accepted: 11/25/2018] [Indexed: 12/28/2022]
Abstract
Glutamate is the predominant excitatory neurotransmitter in the ventral respiratory column; however, the contribution of glutamatergic excitation in the individual subregions to respiratory rhythm generation has not been fully delineated. In an adult, in vivo, decerebrate rabbit model during conditions of mild hyperoxic hypercapnia we blocked glutamatergic excitation using the receptor antagonists 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) and d(-)-2-amino-5-phosphonopentanoic acid (AP5). Disfacilitation of the preBötzinger Complex caused a decrease in inspiratory and expiratory duration as well as peak phrenic amplitude and ultimately apnea. Disfacilitation of the Bötzinger Complex caused a decrease in inspiratory and expiratory duration; subsequent disfacilitation of the preBötzinger Complex resulted in complete loss of the respiratory pattern but maintained tonic inspiratory activity. We conclude that glutamatergic drive to the preBötzinger Complex is essential for respiratory rhythm generation. Glutamatergic drive to the Bötzinger Complex significantly affects inspiratory and expiratory phase duration. Bötzinger Complex neurons are responsible for maintaining the silent expiratory phase of the phrenic neurogram.
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Affiliation(s)
| | - Justin R Miller
- Department of Biology, Carthage College, Kenosha, WI, United States
| | | | - Jennifer J Callison
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Robin C Peterson
- Department of Neuroscience, Carthage College, Kenosha, WI, United States
| | - Francis A Hopp
- Zablocki VA Medical Center, Milwaukee, WI, United States
| | - Eckehard A E Stuth
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Milwaukee, WI, United States
| | - Edward J Zuperku
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Zablocki VA Medical Center, Milwaukee, WI, United States
| | - Astrid G Stucke
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Milwaukee, WI, United States.
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37
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Lavezzi AM, Poloniato A, Rovelli R, Lorioli L, Iasi GA, Pusiol T, Barera G, Ferrero S. Massive Amniotic Fluid Aspiration in a Case of Sudden Neonatal Death With Severe Hypoplasia of the Retrotrapezoid/Parafacial Respiratory Group. Front Pediatr 2019; 7:116. [PMID: 31019904 PMCID: PMC6458245 DOI: 10.3389/fped.2019.00116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/11/2019] [Indexed: 11/24/2022] Open
Abstract
We report a case of a baby, who, after pregnancy complicated by maternal Addison's disease and Hashimoto's thyroiditis and natural delivery, unexpectedly presented a cardiorespiratory collapse and died 1 hour after birth without responding to prolonged neonatal resuscitation maneuvers. The cause of death was reliably established by carrying out a forensic postmortem examination. More specifically, the histological examination of the lungs showed the presence of abundant endoalveolar and endobronchial cornea scales caused by absorption of amniotic fluid. The neuropathological examination of the brainstem highlighted severe hypodevelopment of the retrotrapezoid/parafacial respiratory group, which is a complex of neurons located in the caudal pons that is involved in respiratory rhythm coordination, especially expiration, in conditions of enhanced respiratory drive, as well as in chemoreception. This neuropathological finding shed new light on the mechanisms underlying the massive amniotic fluid aspiration which led to this early death.
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Affiliation(s)
- Anna M Lavezzi
- Department of Biomedical, Surgical and Dental Sciences, Lino Rossi Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, University of Milan, Milan, Italy
| | | | | | - Laura Lorioli
- Neonatal Unit, IRCCS Ospedale San Raffaele, Milan, Italy
| | | | - Teresa Pusiol
- Institute of Pathology, Hospital of Rovereto, Rovereto, Italy
| | | | - Stefano Ferrero
- Department of Biomedical, Surgical and Dental Sciences, Lino Rossi Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, University of Milan, Milan, Italy.,Division of Pathology, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
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38
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Vedyasova OA, Kovaleva TE. Role of GABA A Receptors of Parafacial Respiratory Group in Control of Respiration in Rats. Bull Exp Biol Med 2018; 165:711-714. [PMID: 30353348 DOI: 10.1007/s10517-018-4248-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Indexed: 12/01/2022]
Abstract
The role of GABAergic inhibition in the regulation of activity of the parafacial respiratory group was studied on narcotized mature rats. Microinjections of GABAA agonist muscimol into the parafacial respiratory group inhibited external respiration and bioelectrical activity of the diaphragmatic muscle resulting in diminished tidal volume and decreased respiration rate accompanied by prolonged inspiration, expiration, and intervals between the inspiratory bursts in the phrenic electromyogram. In contrast, microinjections of GABAA antagonist bicuculline into this group stimulated respiration and markedly increased its volumetric parameters. In addition, blockade of GABAA receptors affected the expiratory phase and interburst intervals in the phrenic electromyogram, but produced no effect on respiration rate. These findings attested to contribution of GABAA-mediated inhibition into the performance of parafacial respiratory group. The study revealed different roles of GABAA receptors in modulation of the mechanisms of respiration rate control in mature rats and formation of inspiratory motor outputs originating from the parafacial respiratory group.
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Affiliation(s)
- O A Vedyasova
- Department of Human and Animal Physiology, S. P. Korolev Samara National Research University, Samara, Russia.
| | - T E Kovaleva
- Department of Human and Animal Physiology, S. P. Korolev Samara National Research University, Samara, Russia
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39
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Dubois CJ, Cardoit L, Schwarz V, Markkanen M, Airaksinen MS, Uvarov P, Simmers J, Thoby-Brisson M. Role of the K +-Cl - Cotransporter KCC2a Isoform in Mammalian Respiration at Birth. eNeuro 2018; 5:ENEURO.0264-18.2018. [PMID: 30406192 PMCID: PMC6220586 DOI: 10.1523/eneuro.0264-18.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 12/31/2022] Open
Abstract
In central respiratory circuitry, synaptic excitation is responsible for synchronizing neuronal activity in the different respiratory rhythm phases, whereas chloride-mediated inhibition is important for shaping the respiratory pattern itself. The potassium chloride cotransporter KCC2, which serves to maintain low intraneuronal Cl- concentration and thus render chloride-mediated synaptic signaling inhibitory, exists in two isoforms, KCC2a and KCC2b. KCC2 is essential for functional breathing motor control at birth, but the specific contribution of the KCC2a isoform remains unknown. Here, to address this issue, we investigated the respiratory phenotype of mice deficient for KCC2a. In vivo plethysmographic recordings revealed that KCC2a-deficient pups at P0 transiently express an abnormally low breathing rate and a high occurrence of apneas. Immunostainings confirmed that KCC2a is normally expressed in the brainstem neuronal groups involved in breathing (pre-Bötzinger complex, parafacial respiratory group, hypoglossus nucleus) and is absent in these regions in the KCC2a-/- mutant. However, in variously reduced in vitro medullary preparations, spontaneous rhythmic respiratory activity is similar to that expressed in wild-type preparations, as is hypoglossal motor output, and no respiratory pauses are detected, suggesting that the rhythm-generating networks are not intrinsically affected in mutants at P0. In contrast, inhibitory neuromodulatory influences exerted by the pons on respiratory rhythmogenesis are stronger in the mutant, thereby explaining the breathing anomalies observed in vivo. Thus, our results indicate that the KCC2a isoform is important for establishing proper breathing behavior at the time of birth, but by acting at sites that are extrinsic to the central respiratory networks themselves.
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Affiliation(s)
- Christophe J. Dubois
- Institut de Neurosciences Cognitives et Intégratives D’Aquitaine, CNRS UMR 5287, Université de Bordeaux, Bordeaux 33076, France
| | - Laura Cardoit
- Institut de Neurosciences Cognitives et Intégratives D’Aquitaine, CNRS UMR 5287, Université de Bordeaux, Bordeaux 33076, France
| | - Veronika Schwarz
- Institut de Neurosciences Cognitives et Intégratives D’Aquitaine, CNRS UMR 5287, Université de Bordeaux, Bordeaux 33076, France
| | - Marika Markkanen
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki Finland
| | - Matti S. Airaksinen
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki Finland
| | - Pavel Uvarov
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki Finland
| | - John Simmers
- Institut de Neurosciences Cognitives et Intégratives D’Aquitaine, CNRS UMR 5287, Université de Bordeaux, Bordeaux 33076, France
| | - Muriel Thoby-Brisson
- Institut de Neurosciences Cognitives et Intégratives D’Aquitaine, CNRS UMR 5287, Université de Bordeaux, Bordeaux 33076, France
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40
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The Expression of Galanin in the Parafacial Respiratory Group and its Effects on Respiration in Neonatal Rats. Neuroscience 2018; 384:1-13. [PMID: 29772344 DOI: 10.1016/j.neuroscience.2018.05.009] [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] [Received: 07/12/2016] [Revised: 05/02/2018] [Accepted: 05/04/2018] [Indexed: 11/23/2022]
Abstract
The inhibitory peptide galanin is expressed within the retrotrapezoidal nucleus (RTN) - a key central chemoreceptor site that also contains the active expiratory oscillator. It was previously reported that microinjection of galanin into pre-Bötzinger complex - containing the inspiratory oscillator - exerts inhibitory effects on inspiratory motor output and respiratory rhythm. In neonatal rats, the present study aimed to investigate: (1) expression of galanin within the parafacial respiratory group (pFRG), which overlaps anatomically and functionally with the adult RTN, and; (2) effects of galanin on respiratory rhythm using the in vitro brainstem-spinal cord preparation. We showed that 14 ± 2% of Phox2b-immunoreactive (ir) neurons in the parafacial region were also galanin-ir. Galanin peptide expression was confirmed within 3/9 CO2-sensitive, Phox2b-ir Pre-Inspiratory neurons (Pre-I) recorded in parafacial region. Bath application of galanin (0.1-0.2 µM): (1) decreased the duration of membrane depolarization in both Pre-I and inspiratory pFRG neurons, and; (2) decreased the number of C4 bursts that were associated with each burst in Pre-I neurons within the pFRG. In preparations showing episodic breathing at baseline, the respiratory patterning reverted to the 'normal' pattern of single, uniformly rhythmic C4 bursts (n = 10). In preparations with normal respiratory patterning at baseline, slowing of C4 rhythm (n = 7) resulted although rhythmic bursting in recorded Pre-I neurons remained unperturbed (n = 6). This study therefore demonstrates that galanin is expressed within the pFRG of neonatal rats, including neurons that are intrinsically chemosensitive. Overall the peptide has an inhibitory effect on inspiratory motor output, as previously shown in adults.
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41
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Johnson CS, Bains JS, Watts AG. Neurotransmitter diversity in pre-synaptic terminals located in the parvicellular neuroendocrine paraventricular nucleus of the rat and mouse hypothalamus. J Comp Neurol 2018; 526:1287-1306. [PMID: 29424419 DOI: 10.1002/cne.24407] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 01/24/2018] [Accepted: 01/25/2018] [Indexed: 02/02/2023]
Abstract
Virtually all rodent neuroendocrine corticotropin-releasing-hormone (CRH) neurons are in the dorsal medial parvicellular (mpd) part of the paraventricular nucleus of the hypothalamus (PVH). They form the final common pathway for adrenocortical stress responses. Their activity is controlled by sets of GABA-, glutamate-, and catecholamine-containing inputs arranged in an interactive pre-motor network. Defining the nature and arrangement of these inputs can help clarify how stressor type and intensity information is conveyed to neuroendocrine neurons. Here we use immunohistochemistry with high-resolution 3-dimensional image analyses to examine the arrangement of single- and co-occurring GABA, glutamate, and catecholamine markers in synaptophysin-defined pre-synaptic terminals in the PVHmpd of unstressed rats and Crh-IRES-Cre;Ai14 transgenic mice: respectively, vesicular glutamate transporter 2 (VGluT2), vesicular GABA transporter (VGAT), dopamine β-hydroxylase (DBH), and phenylethanolamine n-methyltransferase (PNMT). Just over half of all PVHmpd pre-synaptic terminals contain VGAT, with slightly less containing VGluT2. The vast majority of terminal appositions with mouse CRH neurons occur non-somatically. However, there are significantly more somatic VGAT than VGluT2 appositions. In the rat PVHmpd, about five times as many pre-synaptic terminals contain PNMT than DBH only. However, because epinephrine release has never been detected in the PVH, PNMT terminals may functionally be noradrenergic not adrenergic. PNMT and VGluT2 co-occur in some pre-synaptic terminals indicating the potential for co-transmission of glutamate and norepinephrine. Collectively, these results provide a structural basis for how GABA/glutamate/catecholamine interactions enable adrenocortical responses to fast-onset interosensory stimuli, and more broadly, how combinations of PVH neurotransmitters and neuromodulators interact dynamically to control adrenocortical activity.
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Affiliation(s)
- Caroline S Johnson
- The Department of Biological Sciences, USC Dornsife College of Letters, Arts, and Sciences, and Neuroscience, Graduate Program, University of Southern California, Los Angeles, California
| | - Jaideep S Bains
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada
| | - Alan G Watts
- The Department of Biological Sciences, USC Dornsife College of Letters, Arts, and Sciences, and Neuroscience, Graduate Program, University of Southern California, Los Angeles, California
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42
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Guyenet PG, Bayliss DA, Stornetta RL, Kanbar R, Shi Y, Holloway BB, Souza GMPR, Basting TM, Abbott SBG, Wenker IC. Interdependent feedback regulation of breathing by the carotid bodies and the retrotrapezoid nucleus. J Physiol 2017; 596:3029-3042. [PMID: 29168167 DOI: 10.1113/jp274357] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/02/2017] [Indexed: 12/13/2022] Open
Abstract
The retrotrapezoid nucleus (RTN) regulates breathing in a CO2 - and state-dependent manner. RTN neurons are glutamatergic and innervate principally the respiratory pattern generator; they regulate multiple aspects of breathing, including active expiration, and maintain breathing automaticity during non-REM sleep. RTN neurons encode arterial PCO2 /pH via cell-autonomous and paracrine mechanisms, and via input from other CO2 -responsive neurons. In short, RTN neurons are a pivotal structure for breathing automaticity and arterial PCO2 homeostasis. The carotid bodies stimulate the respiratory pattern generator directly and indirectly by activating RTN via a neuronal projection originating within the solitary tract nucleus. The indirect pathway operates under normo- or hypercapnic conditions; under respiratory alkalosis (e.g. hypoxia) RTN neurons are silent and the excitatory input from the carotid bodies is suppressed. Also, silencing RTN neurons optogenetically quickly triggers a compensatory increase in carotid body activity. Thus, in conscious mammals, breathing is subject to a dual and interdependent feedback regulation by chemoreceptors. Depending on the circumstance, the activity of the carotid bodies and that of RTN vary in the same or the opposite directions, producing additive or countervailing effects on breathing. These interactions are mediated either via changes in blood gases or by brainstem neuronal connections, but their ultimate effect is invariably to minimize arterial PCO2 fluctuations. We discuss the potential relevance of this dual chemoreceptor feedback to cardiorespiratory abnormalities present in diseases in which the carotid bodies are hyperactive at rest, e.g. essential hypertension, obstructive sleep apnoea and heart failure.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Benjamin B Holloway
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Tyler M Basting
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University, New Orleans, Louisiana 70112, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ian C Wenker
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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Kaur S, Wang JL, Ferrari L, Thankachan S, Kroeger D, Venner A, Lazarus M, Wellman A, Arrigoni E, Fuller PM, Saper CB. A Genetically Defined Circuit for Arousal from Sleep during Hypercapnia. Neuron 2017; 96:1153-1167.e5. [PMID: 29103805 DOI: 10.1016/j.neuron.2017.10.009] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 09/11/2017] [Accepted: 10/04/2017] [Indexed: 12/21/2022]
Abstract
The precise neural circuitry that mediates arousal during sleep apnea is not known. We previously found that glutamatergic neurons in the external lateral parabrachial nucleus (PBel) play a critical role in arousal to elevated CO2 or hypoxia. Because many of the PBel neurons that respond to CO2 express calcitonin gene-related peptide (CGRP), we hypothesized that CGRP may provide a molecular identifier of the CO2 arousal circuit. Here, we report that selective chemogenetic and optogenetic activation of PBelCGRP neurons caused wakefulness, whereas optogenetic inhibition of PBelCGRP neurons prevented arousal to CO2, but not to an acoustic tone or shaking. Optogenetic inhibition of PBelCGRP terminals identified a network of forebrain sites under the control of a PBelCGRP switch that is necessary to arouse animals from hypercapnia. Our findings define a novel cellular target for interventions that may prevent sleep fragmentation and the attendant cardiovascular and cognitive consequences seen in obstructive sleep apnea. VIDEO ABSTRACT.
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Affiliation(s)
- Satvinder Kaur
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Joshua L Wang
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Loris Ferrari
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Stephen Thankachan
- Department of Psychiatry, Harvard Medical School & VA Boston Healthcare, 1400 VFW Parkway, West Roxbury, MA, USA
| | - Daniel Kroeger
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Anne Venner
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Michael Lazarus
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Japan
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Elda Arrigoni
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Patrick M Fuller
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Clifford B Saper
- Department of Neurology, Program in Neuroscience, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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Neuromedin B Expression Defines the Mouse Retrotrapezoid Nucleus. J Neurosci 2017; 37:11744-11757. [PMID: 29066557 DOI: 10.1523/jneurosci.2055-17.2017] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/09/2017] [Indexed: 11/21/2022] Open
Abstract
The retrotrapezoid nucleus (RTN) consists, by definition, of Phox2b-expressing, glutamatergic, non-catecholaminergic, noncholinergic neurons located in the parafacial region of the medulla oblongata. An unknown proportion of RTN neurons are central respiratory chemoreceptors and there is mounting evidence for biochemical diversity among these cells. Here, we used multiplexed in situ hybridization and single-cell RNA-Seq in male and female mice to provide a more comprehensive view of the phenotypic diversity of RTN neurons. We now demonstrate that the RTN of mice can be identified with a single and specific marker, Neuromedin B mRNA (Nmb). Most (∼75%) RTN neurons express low-to-moderate levels of Nmb and display chemoreceptor properties. Namely they are activated by hypercapnia, but not by hypoxia, and express proton sensors, TASK-2 and Gpr4. These Nmb-low RTN neurons also express varying levels of transcripts for Gal, Penk, and Adcyap1, and receptors for substance P, orexin, serotonin, and ATP. A subset of RTN neurons (∼20-25%), typically larger than average, express very high levels of Nmb mRNA. These Nmb-high RTN neurons do not express Fos after hypercapnia and have low-to-undetectable levels of Kcnk5 or Gpr4 transcripts; they also express Adcyap1, but are essentially devoid of Penk and Gal transcripts. In male rats, Nmb is also a marker of the RTN but, unlike in mice, this gene is expressed by other types of nearby neurons located within the ventromedial medulla. In sum, Nmb is a selective marker of the RTN in rodents; Nmb-low neurons, the vast majority, are central respiratory chemoreceptors, whereas Nmb-high neurons likely have other functions.SIGNIFICANCE STATEMENT Central respiratory chemoreceptors regulate arterial PCO2 by adjusting lung ventilation. Such cells have recently been identified within the retrotrapezoid nucleus (RTN), a brainstem nucleus defined by genetic lineage and a cumbersome combination of markers. Using single-cell RNA-Seq and multiplexed in situ hybridization, we show here that a single marker, Neuromedin B mRNA (Nmb), identifies RTN neurons in rodents. We also suggest that >75% of these Nmb neurons are chemoreceptors because they are strongly activated by hypercapnia and express high levels of proton sensors (Kcnk5 and Gpr4). The other RTN neurons express very high levels of Nmb, but low levels of Kcnk5/Gpr4/pre-pro-galanin/pre-pro-enkephalin, and do not respond to hypercapnia. Their function is unknown.
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Jarvie BC, Palmiter RD. HSD2 neurons in the hindbrain drive sodium appetite. Nat Neurosci 2016; 20:167-169. [PMID: 27918529 DOI: 10.1038/nn.4451] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 11/02/2016] [Indexed: 12/11/2022]
Abstract
Sodium-depleted animals develop an appetite for aversive concentrations of sodium. Here we show that chemogenetic activation of aldosterone-sensitive neurons that express 11β-hydroxysteroid dehydrogenase type 2 (HSD2) in the nucleus of the solitary tract is sufficient to drive consumption of sodium-containing solutions in mice, independently of thirst or hunger. These HSD2-positive neurons are necessary for full expression of sodium appetite and have distinct downstream targets that are activated during sodium depletion.
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Affiliation(s)
- Brooke C Jarvie
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Richard D Palmiter
- Department of Biochemistry, University of Washington, Seattle, Washington, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, Washington, USA
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Voltage-Dependent Rhythmogenic Property of Respiratory Pre-Bötzinger Complex Glutamatergic, Dbx1-Derived, and Somatostatin-Expressing Neuron Populations Revealed by Graded Optogenetic Inhibition. eNeuro 2016; 3:eN-NWR-0081-16. [PMID: 27275007 PMCID: PMC4891766 DOI: 10.1523/eneuro.0081-16.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Accepted: 05/12/2016] [Indexed: 11/21/2022] Open
Abstract
The rhythm of breathing in mammals, originating within the brainstem pre-Bötzinger complex (pre-BötC), is presumed to be generated by glutamatergic neurons, but this has not been directly demonstrated. Additionally, developmental expression of the transcription factor Dbx1 or expression of the neuropeptide somatostatin (Sst), has been proposed as a marker for the rhythmogenic pre-BötC glutamatergic neurons, but it is unknown whether these other two phenotypically defined neuronal populations are functionally equivalent to glutamatergic neurons with regard to rhythm generation. To address these problems, we comparatively investigated, by optogenetic approaches, the roles of pre-BötC glutamatergic, Dbx1-derived, and Sst-expressing neurons in respiratory rhythm generation in neonatal transgenic mouse medullary slices in vitro and also more intact adult perfused brainstem-spinal cord preparations in situ. We established three different triple-transgenic mouse lines with Cre-driven Archaerhodopsin-3 (Arch) expression selectively in glutamatergic, Dbx1-derived, or Sst-expressing neurons for targeted photoinhibition. In each line, we identified subpopulations of rhythmically active, Arch-expressing pre-BötC inspiratory neurons by whole-cell recordings in medullary slice preparations in vitro, and established that Arch-mediated hyperpolarization of these inspiratory neurons was laser power dependent with equal efficacy. By site- and population-specific graded photoinhibition, we then demonstrated that inspiratory frequency was reduced by each population with the same neuronal voltage-dependent frequency control mechanism in each state of the respiratory network examined. We infer that enough of the rhythmogenic pre-BötC glutamatergic neurons also have the Dbx1 and Sst expression phenotypes, and thus all three phenotypes share the same voltage-dependent frequency control property.
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Guyenet PG, Bayliss DA, Stornetta RL, Ludwig MG, Kumar NN, Shi Y, Burke PGR, Kanbar R, Basting TM, Holloway BB, Wenker IC. Proton detection and breathing regulation by the retrotrapezoid nucleus. J Physiol 2016; 594:1529-51. [PMID: 26748771 PMCID: PMC4799966 DOI: 10.1113/jp271480] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/04/2016] [Indexed: 01/26/2023] Open
Abstract
We discuss recent evidence which suggests that the principal central respiratory chemoreceptors are located within the retrotrapezoid nucleus (RTN) and that RTN neurons are directly sensitive to [H(+) ]. RTN neurons are glutamatergic. In vitro, their activation by [H(+) ] requires expression of a proton-activated G protein-coupled receptor (GPR4) and a proton-modulated potassium channel (TASK-2) whose transcripts are undetectable in astrocytes and the rest of the lower brainstem respiratory network. The pH response of RTN neurons is modulated by surrounding astrocytes but genetic deletion of RTN neurons or deletion of both GPR4 and TASK-2 virtually eliminates the central respiratory chemoreflex. Thus, although this reflex is regulated by innumerable brain pathways, it seems to operate predominantly by modulating the discharge rate of RTN neurons, and the activation of RTN neurons by hypercapnia may ultimately derive from their intrinsic pH sensitivity. RTN neurons increase lung ventilation by stimulating multiple aspects of breathing simultaneously. They stimulate breathing about equally during quiet wake and non-rapid eye movement (REM) sleep, and to a lesser degree during REM sleep. The activity of RTN neurons is regulated by inhibitory feedback and by excitatory inputs, notably from the carotid bodies. The latter input operates during normo- or hypercapnia but fails to activate RTN neurons under hypocapnic conditions. RTN inhibition probably limits the degree of hyperventilation produced by hypocapnic hypoxia. RTN neurons are also activated by inputs from serotonergic neurons and hypothalamic neurons. The absence of RTN neurons probably underlies the sleep apnoea and lack of chemoreflex that characterize congenital central hypoventilation syndrome.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | | | - Natasha N Kumar
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Peter G R Burke
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Tyler M Basting
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Benjamin B Holloway
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ian C Wenker
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
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48
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Silva JN, Tanabe FM, Moreira TS, Takakura AC. Neuroanatomical and physiological evidence that the retrotrapezoid nucleus/parafacial region regulates expiration in adult rats. Respir Physiol Neurobiol 2016; 227:9-22. [PMID: 26900003 DOI: 10.1016/j.resp.2016.02.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 02/11/2016] [Accepted: 02/11/2016] [Indexed: 01/09/2023]
Abstract
The rostroventrolateral medulla contains two functional neuronal populations: (1) the parafacial respiratory group (pFRG) neurons and (2) the chemosensitive retrotrapezoid nucleus (RTN) neurons. Using anatomical and physiological techniques, we investigated the role of the RTN/pFRG in CO2-induced active expiration (AE) in urethane-anesthetized rats. Anterograde tracing using biotinylated dextran amine (BDA) revealed dense neuronal projections emanating from the RTN/pFRG to the caudal ventral respiratory group (cVRG), 60% of which contained vesicular glutamate transporter-2. The minority (16%) of the RTN projections to the cVRG emanated from Phox2b positive neurons. Hypercapnia (10% CO2) increased DiaEMG and elicited AbdEMG activity. Bilateral injections of muscimol (2mM) into the RTN/pFRG reduced the activation of DiaEMG (23±4%) and abolished AE-induced by chemoreflex stimulation. Taken together, these results support the presence of direct excitatory projections from RTN/pFRG neurons to cVRG expiratory premotor neurons, playing a role in the generation/modulation of AE.
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Affiliation(s)
- Josiane N Silva
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (USP), 05508-000 São Paulo, SP, Brazil
| | - Fabiola M Tanabe
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (USP), 05508-000 São Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo (USP), 05508-000 São Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (USP), 05508-000 São Paulo, SP, Brazil.
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50
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Le S, Turner AJ, Parker LM, Burke PG, Kumar NN, Goodchild AK, McMullan S. Somatostatin 2a receptors are not expressed on functionally identified respiratory neurons in the ventral respiratory column of the rat. J Comp Neurol 2015; 524:1384-98. [PMID: 26470751 DOI: 10.1002/cne.23912] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 10/09/2015] [Accepted: 10/12/2015] [Indexed: 01/09/2023]
Abstract
Microinjection of somatostatin (SST) causes site-specific effects on respiratory phase transition, frequency, and amplitude when microinjected into the ventrolateral medulla (VLM) of the anesthetized rat, suggesting selective expression of SST receptors on different functional classes of respiratory neurons. Of the six subtypes of SST receptor, somatostatin 2a (sst2a ) is the most prevalent in the VLM, and other investigators have suggested that glutamatergic neurons in the preBötzinger Complex (preBötC) that coexpress neurokinin-1 receptor (NK1R), SST, and sst2a are critical for the generation of respiratory rhythm. However, quantitative data describing the distribution of sst2a in respiratory compartments other than preBötC, or on functionally identified respiratory neurons, is absent. Here we examine the medullary expression of sst2a with particular reference to glycinergic/expiratory neurons in the Bötzinger Complex (BötC) and NK1R-immunoreactive/inspiratory neurons in the preBötC. We found robust sst2a expression at all rostrocaudal levels of the VLM, including a large proportion of catecholaminergic neurons, but no colocalization of sst2a and glycine transporter 2 mRNA in the BötC. In the preBötC 54% of sst2a -immunoreactive neurons were also positive for NK1R. sst2a was not observed in any of 52 dye-labeled respiratory interneurons, including seven BötC expiratory-decrementing and 11 preBötC preinspiratory neurons. We conclude that sst2a is not expressed on BötC respiratory neurons and that phasic respiratory activity is a poor predictor of sst2a expression in the preBötC. Therefore, sst2a is unlikely to underlie responses to BötC SST injection, and is sparse or absent on respiratory neurons identified by classical functional criteria. J. Comp. Neurol. 524:1384-1398, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Sheng Le
- Faculty of Medicine & Health Sciences, Macquarie University, NSW, Australia
| | - Anita J Turner
- Faculty of Medicine & Health Sciences, Macquarie University, NSW, Australia
| | - Lindsay M Parker
- ARC Center of Excellence for Nanoscale BioPhotonics, Macquarie University, NSW, Australia
| | - Peter G Burke
- Neuroscience Research Australia, Randwick, NSW, Australia
| | - Natasha N Kumar
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Ann K Goodchild
- Faculty of Medicine & Health Sciences, Macquarie University, NSW, Australia
| | - Simon McMullan
- Faculty of Medicine & Health Sciences, Macquarie University, NSW, Australia
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