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Missaghi K, Le Gal JP, Mercier J, Grover M, Beauséjour PA, Chartré S, Messihad O, Auclair F, Dubuc R. Revisiting the two rhythm generators for respiration in lampreys. Front Neuroanat 2024; 17:1270535. [PMID: 38250023 PMCID: PMC10796688 DOI: 10.3389/fnana.2023.1270535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 11/17/2023] [Indexed: 01/23/2024] Open
Abstract
In lampreys, respiration consists of a fast and a slow rhythm. This study was aimed at characterizing both anatomically and physiologically the brainstem regions involved in generating the two rhythms. The fast rhythm generator has been located by us and others in the rostral hindbrain, rostro-lateral to the trigeminal motor nucleus. More recently, this was challenged by researchers reporting that the fast rhythm generator was located more rostrally and dorsomedially, in a region corresponding to the mesencephalic locomotor region. These contradictory observations made us re-examine the location of the fast rhythm generator using anatomical lesions and physiological recordings. We now confirm that the fast respiratory rhythm generator is in the rostro-lateral hindbrain as originally described. The slow rhythm generator has received less attention. Previous studies suggested that it was composed of bilateral, interconnected rhythm generating regions located in the caudal hindbrain, with ascending projections to the fast rhythm generator. We used anatomical and physiological approaches to locate neurons that could be part of this slow rhythm generator. Combinations of unilateral injections of anatomical tracers, one in the fast rhythm generator area and another in the lateral tegmentum of the caudal hindbrain, were performed to label candidate neurons on the non-injected side of the lateral tegmentum. We found a population of neurons extending from the facial to the caudal vagal motor nuclei, with no clear clustering in the cell distribution. We examined the effects of stimulating different portions of the labeled population on the respiratory activity. The rostro-caudal extent of the population was arbitrarily divided in three portions that were each stimulated electrically or chemically. Stimulation of either of the three sites triggered bursts of discharge characteristic of the slow rhythm, whereas inactivating any of them stopped the slow rhythm. Substance P injected locally in the lateral tegmentum accelerated the slow respiratory rhythm in a caudal hindbrain preparation. Our results show that the fast respiratory rhythm generator consists mostly of a population of neurons rostro-lateral to the trigeminal motor nucleus, whereas the slow rhythm generator is distributed in the lateral tegmentum of the caudal hindbrain.
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Affiliation(s)
- Kianoush Missaghi
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
| | | | - Julien Mercier
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
| | - Martin Grover
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
| | | | - Shannon Chartré
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
| | - Omima Messihad
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - François Auclair
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Réjean Dubuc
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
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2
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Pan YK, Perry SF. The control of breathing in fishes - historical perspectives and the path ahead. J Exp Biol 2023; 226:307288. [PMID: 37097020 DOI: 10.1242/jeb.245529] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
The study of breathing in fishes has featured prominently in Journal of Experimental Biology (JEB), particularly during the latter half of the past century. Indeed, many of the seminal discoveries in this important sub-field of comparative respiratory physiology were reported first in JEB. The period spanning 1960-1990 (the 'golden age of comparative respiratory physiology') witnessed intense innovation in the development of methods to study the control of breathing. Many of the guiding principles of piscine ventilatory control originated during this period, including our understanding of the dominance of O2 as the driver of ventilation in fish. However, a critical issue - the identity of the peripheral O2 chemoreceptors - remained unanswered until methods for cell isolation, culture and patch-clamp recording established that gill neuroepithelial cells (NECs) respond to hypoxia in vitro. Yet, the role of the NECs and other putative peripheral or central chemoreceptors in the control of ventilation in vivo remains poorly understood. Further progress will be driven by the implementation of genetic tools, most of which can be used in zebrafish (Danio rerio). These tools include CRISPR/Cas9 for selective gene knockout, and Tol2 systems for transgenesis, the latter of which enables optogenetic stimulation of cellular pathways, cellular ablation and in vivo cell-specific biosensing. Using these methods, the next period of discovery will see the identification of the peripheral sensory pathways that initiate ventilatory responses, and will elucidate the nature of their integration within the central nervous system and their link to the efferent motor neurons that control breathing.
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Affiliation(s)
- Yihang Kevin Pan
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
| | - Steve F Perry
- Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
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3
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Gourine AV, Spyer KM. Geoff Burnstock, purinergic signalling, and chemosensory control of breathing. Auton Neurosci 2021; 235:102839. [PMID: 34198056 DOI: 10.1016/j.autneu.2021.102839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/11/2021] [Accepted: 06/20/2021] [Indexed: 12/14/2022]
Abstract
This article is the authors' contribution to the tribute issue in honour of Geoffrey Burnstock, the founder of this journal and the field of purinergic signalling. We give a brief account of the results of experimental studies which at the beginning received valuable input from Geoff, who both directly and indirectly influenced our research undertaken over the last two decades. Research into the mechanisms controlling breathing identified ATP as the common mediator of the central and peripheral chemosensory transduction. Studies of the sources and mechanisms of chemosensory ATP release in the CNS suggested that this signalling pathway is universally engaged in conditions of increased metabolic demand by brain glial cells - astrocytes. Astrocytes appear to function as versatile CNS metabolic sensors that detect changes in brain tissue pH, CO2, oxygen, and cerebral perfusion pressure. Experimental studies on various aspects of astrocyte biology generated data indicating that the function of these omnipresent glial cells and communication between astrocytes and neurons are governed by purinergic signalling, - first discovered by Geoff Burnstock in the 70's and researched through his entire scientific career.
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Affiliation(s)
- Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London WC1E 6BT, UK.
| | - K Michael Spyer
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
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4
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The lamprey respiratory network: Some evolutionary aspects. Respir Physiol Neurobiol 2021; 294:103766. [PMID: 34329767 DOI: 10.1016/j.resp.2021.103766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/19/2021] [Accepted: 07/25/2021] [Indexed: 01/25/2023]
Abstract
Breathing is a complex behaviour that involves rhythm generating networks. In this review, we examine the main characteristics of respiratory rhythm generation in vertebrates and, in particular, we describe the main results of our studies on the role of neural mechanisms involved in the neuromodulation of the lamprey respiration. The lamprey respiratory rhythm generator is located in the paratrigeminal respiratory group (pTRG) and shows similarities with the mammalian preBötzinger complex. In fact, within the pTRG a major role is played by glutamate, but also GABA and glycine display important contributions. In addition, neuromodulatory influences are exerted by opioids, substance P, acetylcholine and serotonin. Both structures respond to exogenous ATP with a biphasic response and astrocytes there located strongly contribute to the modulation of the respiratory pattern. The results emphasize that some important characteristics of the respiratory rhythm generating network are, to a great extent, maintained throughout evolution.
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5
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Astrocytic contribution to glutamate-related central respiratory chemoreception in vertebrates. Respir Physiol Neurobiol 2021; 294:103744. [PMID: 34302992 DOI: 10.1016/j.resp.2021.103744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/18/2021] [Indexed: 12/24/2022]
Abstract
Central respiratory chemoreceptors play a key role in the respiratory homeostasis by sensing CO2 and H+ in brain and activating the respiratory neural network. This ability of specific brain regions to respond to acidosis and hypercapnia is based on neuronal and glial mechanisms. Several decades ago, glutamatergic transmission was proposed to be involved as a main mechanism in central chemoreception. However, a complete identification of mechanism has been elusive. At the rostral medulla, chemosensitive neurons of the retrotrapezoid nucleus (RTN) are glutamatergic and they are stimulated by ATP released by RTN astrocytes in response to hypercapnia. In addition, recent findings show that caudal medullary astrocytes in brainstem can also contribute as CO2 and H+ sensors that release D-serine and glutamate, both gliotransmitters able to activate the respiratory neural network. In this review, we describe the mammalian astrocytic glutamatergic contribution to the central respiratory chemoreception trying to trace in vertebrates the emergence of several components involved in this process.
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6
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Broadhead MJ, Miles GB. A common role for astrocytes in rhythmic behaviours? Prog Neurobiol 2021; 202:102052. [PMID: 33894330 DOI: 10.1016/j.pneurobio.2021.102052] [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: 10/07/2020] [Revised: 03/03/2021] [Accepted: 04/13/2021] [Indexed: 01/16/2023]
Abstract
Astrocytes are a functionally diverse form of glial cell involved in various aspects of nervous system infrastructure, from the metabolic and structural support of neurons to direct neuromodulation of synaptic activity. Investigating how astrocytes behave in functionally related circuits may help us understand whether there is any conserved logic to the role of astrocytes within neuronal networks. Astrocytes are implicated as key neuromodulatory cells within neural circuits that control a number of rhythmic behaviours such as breathing, locomotion and circadian sleep-wake cycles. In this review, we examine the evidence that astrocytes are directly involved in the regulation of the neural circuits underlying six different rhythmic behaviours: locomotion, breathing, chewing, gastrointestinal motility, circadian sleep-wake cycles and oscillatory feeding behaviour. We discuss how astrocytes are integrated into the neuronal networks that regulate these behaviours, and identify the potential gliotransmission signalling mechanisms involved. From reviewing the evidence of astrocytic involvement in a range of rhythmic behaviours, we reveal a heterogenous array of gliotransmission mechanisms, which help to regulate neuronal networks. However, we also observe an intriguing thread of commonality, in the form of purinergic gliotransmission, which is frequently utilised to facilitate feedback inhibition within rhythmic networks to constrain a given behaviour within its operational range.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK.
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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7
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Bozzo M, Lacalli TC, Obino V, Caicci F, Marcenaro E, Bachetti T, Manni L, Pestarino M, Schubert M, Candiani S. Amphioxus neuroglia: Molecular characterization and evidence for early compartmentalization of the developing nerve cord. Glia 2021; 69:1654-1678. [PMID: 33624886 DOI: 10.1002/glia.23982] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/02/2021] [Accepted: 02/09/2021] [Indexed: 12/19/2022]
Abstract
Glial cells play important roles in the development and homeostasis of metazoan nervous systems. However, while their involvement in the development and function in the central nervous system (CNS) of vertebrates is increasingly well understood, much less is known about invertebrate glia and the evolutionary history of glial cells more generally. An investigation into amphioxus glia is therefore timely, as this organism is the best living proxy for the last common ancestor of all chordates, and hence provides a window into the role of glial cell development and function at the transition of invertebrates and vertebrates. We report here our findings on amphioxus glia as characterized by molecular probes correlated with anatomical data at the transmission electron microscopy (TEM) level. The results show that amphioxus glial lineages express genes typical of vertebrate astroglia and radial glia, and that they segregate early in development, forming what appears to be a spatially separate cell proliferation zone positioned laterally, between the dorsal and ventral zones of neural cell proliferation. Our study provides strong evidence for the presence of vertebrate-type glial cells in amphioxus, while highlighting the role played by segregated progenitor cell pools in CNS development. There are implications also for our understanding of glial cells in a broader evolutionary context, and insights into patterns of precursor cell deployment in the chordate nerve cord.
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Affiliation(s)
- Matteo Bozzo
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
| | - Thurston C Lacalli
- Biology Department, University of Victoria, Victoria, British Columbia, Canada
| | - Valentina Obino
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | | | - Emanuela Marcenaro
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,Centre of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Tiziana Bachetti
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
| | - Lucia Manni
- Centre of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Mario Pestarino
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
| | - Michael Schubert
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer, Villefranche-sur-Mer, France
| | - Simona Candiani
- Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy
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8
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Burton MT, Santin JM. A direct excitatory action of lactate ions in the central respiratory network of bullfrogs, Lithobates catesbeianus. ACTA ACUST UNITED AC 2020; 223:jeb.235705. [PMID: 33161381 DOI: 10.1242/jeb.235705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 11/03/2020] [Indexed: 12/14/2022]
Abstract
Chemoreceptors that detect O2 and CO2/pH regulate ventilation. However, recent work shows that lactate ions activate arterial chemoreceptors independent of pH to stimulate breathing. Although lactate rises in the central nervous system (CNS) during metabolic challenges, the ability of lactate ions to enhance ventilation by directly targeting the central respiratory network remains unclear. To address this possibility, we isolated the amphibian brainstem-spinal cord and found that small increases in CNS lactate stimulate motor output that causes breathing. In addition, lactate potentiated the excitatory postsynaptic strength of respiratory motor neurons, thereby coupling central lactate to the excitatory drive of neurons that trigger muscle contraction. Lactate did not affect motor output through pH or pyruvate metabolism, arguing for sensitivity to lactate anions per se. In sum, these results introduce a mechanism whereby lactate ions in the CNS match respiratory motor output to metabolic demands.
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Affiliation(s)
- Michael T Burton
- The University of North Carolina at Greensboro, Department of Biology, Greensboro, NC 27412, USA
| | - Joseph M Santin
- The University of North Carolina at Greensboro, Department of Biology, Greensboro, NC 27412, USA
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9
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Pan YK, Perry SF. Neuroendocrine control of breathing in fish. Mol Cell Endocrinol 2020; 509:110800. [PMID: 32240728 DOI: 10.1016/j.mce.2020.110800] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/21/2020] [Accepted: 03/23/2020] [Indexed: 10/24/2022]
Abstract
Beginning with the discovery more than 35 years ago that oxygen chemoreceptors of the fish gill are enriched with serotonin, numerous studies have examined the importance of this, and other neuroendocrine factors in piscine chemoreceptor function, and in particular on the chemoreceptor-mediated reflex control of breathing. However, despite these studies, there is continued debate as to the role of neuroendocrine factors in the initiation or modulation of breathing during environmental disturbances or physical activity. In this review, we summarize the state-of-knowledge surrounding the neuroendocrine control of oxygen chemoreception in fish and the associated reflex adjustments to ventilation. We focus on neurohumoral substances that either are present in chemosensory cells or those that are localised elsewhere but have also been implicated in the direct control of breathing. These substances include serotonin, catecholamines (adrenaline and noradrenaline), acetylcholine, purines and gaseous neurotransmitters. Despite the growing indirect evidence for an involvement of these neuroendocrine factors in chemoreception and ventilatory control, direct evidence awaits the incorporation of novel methods currently under development.
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Affiliation(s)
- Yihang Kevin Pan
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada
| | - Steve F Perry
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada.
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10
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Cinelli E, Mutolo D, Iovino L, Pantaleo T, Bongianni F. Key role of 5-HT 1A receptors in the modulation of the neuronal network underlying the respiratory rhythm generation in lampreys. Eur J Neurosci 2020; 52:3903-3917. [PMID: 32378271 DOI: 10.1111/ejn.14769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 04/06/2020] [Accepted: 04/29/2020] [Indexed: 12/17/2022]
Abstract
In mammals, 5-HTexcitatory respiratory effects imply 5-HT1A receptor-mediated disinhibition of pre-Bötzinger complex neurons. In the lamprey, 5-HT1A receptors are involved in the neural control of locomotion, but their role in the respiratory regulation, particularly at the level of the putative respiratory rhythm generator, the paratrigeminal respiratory group (pTRG), is not known. We here investigate the respiratory function of inhibitory 5-HT1A receptors within the pTRG of the isolated brainstem of the adult lamprey. The 5-HT1A receptor agonists either bath applied or microinjected into the pTRG did not cause significant effects. However, the selective 5-HT1A receptor antagonist (S)-WAY 100135 bath applied or microinjected into the pTRG induced depressing respiratory effects or even apnoea, thus revealing that 5-HT exerts a 5-HT1A receptor-mediated potent tonic influence on respiration and contributes to maintain baseline levels of respiratory activity. Microinjections of strychnine or bicuculline, either alone or in combination, into the pTRG prevented (S)-WAY 100135-induced apnoea. In addition, immunohistochemical studies corroborate the present findings suggesting that 5-HT1A receptors are widely expressed in close apposition to the soma of glycine-immunoreactive cells located within the pTRG region. The results show that in the lamprey respiratory network, 5-HT exerts a tonic influence on respiration by a potent inhibitory control on both GABAergic and glycinergic mechanisms. The observed disinhibitory effects resemble the excitatory respiratory modulation exerted by 5-HT1A receptor-mediated inhibition of glycinergic and/or GABAergic neurons present in mammals, supporting the notion that some features of the neuronal network subserving respiratory rhythm generation are highly conserved throughout phylogeny.
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Affiliation(s)
- Elenia Cinelli
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Donatella Mutolo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Ludovica Iovino
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Tito Pantaleo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Fulvia Bongianni
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
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11
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Broadhead MJ, Miles GB. Bi-Directional Communication Between Neurons and Astrocytes Modulates Spinal Motor Circuits. Front Cell Neurosci 2020; 14:30. [PMID: 32180706 PMCID: PMC7057799 DOI: 10.3389/fncel.2020.00030] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/03/2020] [Indexed: 01/22/2023] Open
Abstract
Evidence suggests that astrocytes are not merely supportive cells in the nervous system but may actively participate in the control of neural circuits underlying cognition and behavior. In this study, we examined the role of astrocytes within the motor circuitry of the mammalian spinal cord. Pharmacogenetic manipulation of astrocytic activity in isolated spinal cord preparations obtained from neonatal mice revealed astrocyte-derived, adenosinergic modulation of the frequency of rhythmic output generated by the locomotor central pattern generator (CPG) network. Live Ca2+ imaging demonstrated increased activity in astrocytes during locomotor-related output and in response to the direct stimulation of spinal neurons. Finally, astrocytes were found to respond to neuronally-derived glutamate in a metabotropic glutamate receptor 5 (mGluR5) dependent manner, which in turn drives astrocytic modulation of the locomotor network. Our work identifies bi-directional signaling mechanisms between neurons and astrocytes underlying modulatory feedback control of motor circuits, which may act to constrain network output within optimal ranges for movement.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
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12
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Janes TA, Rousseau JP, Fournier S, Kiernan EA, Harris MB, Taylor BE, Kinkead R. Development of central respiratory control in anurans: The role of neurochemicals in the emergence of air-breathing and the hypoxic response. Respir Physiol Neurobiol 2019; 270:103266. [PMID: 31408738 PMCID: PMC7476778 DOI: 10.1016/j.resp.2019.103266] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/10/2019] [Accepted: 08/05/2019] [Indexed: 01/08/2023]
Abstract
Physiological and environmental factors impacting respiratory homeostasis vary throughout the course of an animal's lifespan from embryo to adult and can shape respiratory development. The developmental emergence of complex neural networks for aerial breathing dates back to ancestral vertebrates, and represents the most important process for respiratory development in extant taxa ranging from fish to mammals. While substantial progress has been made towards elucidating the anatomical and physiological underpinnings of functional respiratory control networks for air-breathing, much less is known about the mechanisms establishing these networks during early neurodevelopment. This is especially true of the complex neurochemical ensembles key to the development of air-breathing. One approach to this issue has been to utilize comparative models such as anuran amphibians, which offer a unique perspective into early neurodevelopment. Here, we review the developmental emergence of respiratory behaviours in anuran amphibians with emphasis on contributions of neurochemicals to this process and highlight opportunities for future research.
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Affiliation(s)
- Tara A Janes
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Jean-Philippe Rousseau
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Stéphanie Fournier
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Elizabeth A Kiernan
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison Wisconsin, USA
| | - Michael B Harris
- Department of Biological Sciences, California State University Long Beach, California, USA
| | - Barbara E Taylor
- Department of Biological Sciences, California State University Long Beach, California, USA
| | - Richard Kinkead
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada.
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13
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Khakh BS. Astrocyte-Neuron Interactions in the Striatum: Insights on Identity, Form, and Function. Trends Neurosci 2019; 42:617-630. [PMID: 31351745 PMCID: PMC6741427 DOI: 10.1016/j.tins.2019.06.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/22/2019] [Accepted: 06/28/2019] [Indexed: 01/09/2023]
Abstract
The physiological functions of astrocytes within neural circuits remain incompletely understood. There has been progress in this regard from recent work on striatal astrocytes, where detailed studies are emerging. In this review, findings on striatal astrocyte identity, form, and function, are summarized with a focus on how astrocytes regulate striatal neurons, circuits, and behavior. Specific features of striatal astrocytes are highlighted to illustrate how they may be specialized to regulate medium spiny neurons (MSNs) by responding to, and altering, excitation and inhibition. Further experiments should reveal additional mechanisms for astrocyte-neuron interactions in the striatum and potentially reveal insights into the functions of astrocytes in neural circuits more generally.
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Affiliation(s)
- Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA.
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14
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Funk GD. Phylogenetically persistent purinergic modulation of central pattern generators for breathing in lamprey and mammals. J Physiol 2017; 595:7011-7012. [PMID: 29027203 DOI: 10.1113/jp274908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Gregory D Funk
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7.,Department of Physiology, Faculty of Medicine and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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