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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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Magalhães KS, Spiller PF, da Silva MP, Kuntze LB, Paton JFR, Machado BH, Moraes DJA. Locus Coeruleus as a vigilance centre for active inspiration and expiration in rats. Sci Rep 2018; 8:15654. [PMID: 30353035 PMCID: PMC6199338 DOI: 10.1038/s41598-018-34047-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/08/2018] [Indexed: 01/05/2023] Open
Abstract
At rest, inspiration is an active process while expiration is passive. However, high chemical drive (hypercapnia or hypoxia) activates central and peripheral chemoreceptors triggering reflex increases in inspiration and active expiration. The Locus Coeruleus contains noradrenergic neurons (A6 neurons) that increase their firing frequency when exposed to hypercapnia and hypoxia. Using recently developed neuronal hyperpolarising technology in conscious rats, we tested the hypothesis that A6 neurons are a part of a vigilance centre for controlling breathing under high chemical drive and that this includes recruitment of active inspiration and expiration in readiness for flight or fight. Pharmacogenetic inhibition of A6 neurons was without effect on resting and on peripheral chemoreceptors-evoked inspiratory, expiratory and ventilatory responses. On the other hand, the number of sighs evoked by systemic hypoxia was reduced. In the absence of peripheral chemoreceptors, inhibition of A6 neurons during hypercapnia did not affect sighing, but reduced both the magnitude and incidence of active expiration, and the frequency and amplitude of inspiration. These changes reduced pulmonary ventilation. Our data indicated that A6 neurons exert a CO2-dependent modulation of expiratory drive. The data also demonstrate that A6 neurons contribute to the CO2-evoked increases in the inspiratory motor output and hypoxia-evoked sighing.
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Affiliation(s)
- Karolyne S Magalhães
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Pedro F Spiller
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Melina P da Silva
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luciana B Kuntze
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Benedito H Machado
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Davi J A Moraes
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil.
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Maddock RJ, Buonocore MH, Miller AR, Yoon JH, Soosman SK, Unruh AM. Abnormal activity-dependent brain lactate and glutamate+glutamine responses in panic disorder. Biol Psychiatry 2013; 73:1111-9. [PMID: 23332354 PMCID: PMC3636170 DOI: 10.1016/j.biopsych.2012.12.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 12/02/2012] [Accepted: 12/27/2012] [Indexed: 01/04/2023]
Abstract
BACKGROUND Prior evidence suggests panic disorder (PD) is characterized by neurometabolic abnormalities, including increased brain lactate responses to neural activation. Increased lactate responses could reflect a general upregulation of metabolic responses to neural activation. However, prior studies in PD have not measured activity-dependent changes in brain metabolites other than lactate. Here we examine activity-dependent changes in both lactate and glutamate plus glutamine (glx) in PD. METHODS Twenty-one PD patients (13 remitted, 8 symptomatic) and 12 healthy volunteers were studied. A single-voxel, J-difference, magnetic resonance spectroscopy editing sequence was used to measure lactate and glx changes in visual cortex induced by visual stimulation. RESULTS The PD patients had significantly greater activity-dependent increases in brain lactate than healthy volunteers. The differences were significant for both remitted and symptomatic PD patients, who did not differ from each other. Activity-dependent changes in glx were significantly smaller in PD patients than in healthy volunteers. The temporal correlation between lactate and glx changes was significantly stronger in control subjects than in PD patients. CONCLUSIONS The novel demonstration that glx responses are diminished and temporally decoupled from lactate responses in PD contradicts the model of a general upregulation of activity-dependent brain metabolic responses in PD. The increase in activity-dependent brain lactate accumulation appears to be a trait feature of PD. Given the close relationship between lactate and pH in the brain, the findings are consistent with a model of brain metabolic and pH dysregulation associated with altered function of acid-sensitive fear circuits contributing to trait vulnerability in PD.
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Affiliation(s)
- Richard J. Maddock
- Department of Psychiatry, University of California Davis Medical Center, Sacramento, CA 95817, USA,Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Michael H. Buonocore
- Department of Radiology, University of California Davis Medical Center, Sacramento, CA 95817, USA,Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Amber R. Miller
- Department of Psychiatry, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Jong H. Yoon
- Department of Psychiatry, University of California Davis Medical Center, Sacramento, CA 95817, USA,Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Steffan K. Soosman
- Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - April M. Unruh
- Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
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The central respiratory chemoreceptor: where is it located?-Invited article. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009. [PMID: 19536502 DOI: 10.1007/978-90-481-2259-2_43] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
We review previous reports on the localization of the central chemoreceptor focusing on our studies that used various experimental techniques including lesioning (brainstem transection and removal of pia mater), analyses of neuronal responses to CO(2) by electrophysiological and optical recording, mapping of CO(2)-excitable neurons by c-fos immunohistochemistry and local acidic stimulation. Among these experimental techniques, voltage imaging with calculation of cross correlation coefficients between the respiratory output activity and each pixel, i.e., correlation coefficient imaging technique, enabled us to effectively analyze imaging data without empirical signal processing. The reviewed studies have indicated that the most superficial layer of the rostral ventral medulla, i.e., the surface portions of the nucleus retrotrapezoideus/parafacial respiratory group, nucleus parapyramidal superficialis and nucleus raphe pallidus, is important in central chemoreception. We suggest that one of the major respiratory rhythm generators, i.e., the preBötzinger complex, is not chemosensitive in itself or rather inhibited by CO(2). Based on our detailed analysis of c-fos immunohistochemistry, we propose a cell-vessel architecture model for the central respiratory chemoreceptor. Primary chemoreceptor cells are mainly located beneath large surface vessels within the marginal glial layer of the ventral medulla, and surround fine penetrating vessels that branch from a large surface vessel. Respiratory neurons in the rostral portion of the ventral respiratory group could be intrinsically chemosensitive, but their role in chemoreception might be secondary. Definitive identification of chemosensitive sites and chemoreceptor cells needs further studies.
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Erlichman JS, Boyer AC, Reagan P, Putnam RW, Ritucci NA, Leiter JC. Chemosensory responses to CO2 in multiple brain stem nuclei determined using a voltage-sensitive dye in brain slices from rats. J Neurophysiol 2009; 102:1577-90. [PMID: 19553484 DOI: 10.1152/jn.00381.2009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We used epifluorescence microscopy and a voltage-sensitive dye, di-8-ANEPPS, to study changes in membrane potential during hypercapnia with or without synaptic blockade in chemosensory brain stem nuclei: the locus coeruleus (LC), the nucleus of the solitary tract, lateral paragigantocellularis nucleus, raphé pallidus, and raphé obscurus and, in putative nonchemosensitive nuclei, the gigantocellularis reticular nucleus and the spinotrigeminal nucleus. We studied the response to hypercapnia in LC cells to evaluate the performance characteristics of the voltage-sensitive dye. Hypercapnia depolarized many LC cells and the voltage responses to hypercapnia were diminished, but not eradicated, by synaptic blockade (there were intrinsically CO2-sensitive cells in the LC). The voltage response to hypercapnia was substantially diminished after inhibiting fast Na+ channels with tetrodotoxin. Thus action potential-related activity was responsible for most of the optical signal that we detected. We systematically examined CO2 sensitivity among cells in brain stem nuclei to test the hypothesis that CO2 sensitivity is a ubiquitous phenomenon, not restricted to nominally CO2 chemosensory nuclei. We found intrinsically CO2 sensitive neurons in all the nuclei that we examined; even the nonchemosensory nuclei had small numbers of intrinsically CO2 sensitive neurons. However, synaptic blockade significantly altered the distribution of CO2-sensitive cells in all of the nuclei so that the cellular response to CO2 in more intact preparations may be difficult to predict based on studies of intrinsic neuronal activity. Thus CO2-sensitive neurons are widely distributed in chemosensory and nonchemosensory nuclei and CO2 sensitivity is dependent on inhibitory and excitatory synaptic activity even within brain slices. Neuronal CO2 sensitivity important for the behavioral response to CO2 in intact animals will thus be determined as much by synaptic mechanisms and patterns of connectivity throughout the brain as by intrinsic CO2 sensitivity.
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Okada Y, Kuwana SI, Masumiya H, Kimura N, Chen Z, Oku Y. Chemosensitive Neuronal Network Organization in the Ventral Medulla Analyzed by Dynamic Voltage-Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 605:353-7. [DOI: 10.1007/978-0-387-73693-8_62] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
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Okada Y, Okada M, Kuwana SI, Kuwana SI, Oyamada Y, Chen Z. The cell-vessel architecture model for the central respiratory chemoreceptor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 580:233-8; discussion 351-9. [PMID: 16683725 DOI: 10.1007/0-387-31311-7_36] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Affiliation(s)
- Yasumasa Okada
- Department of Medicine, Keio University Tsukigase Rehabilitation Center, Izu City, Shizuoka 410-3215 Japan
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Hilaire G. Endogenous noradrenaline affects the maturation and function of the respiratory network: Possible implication for SIDS. Auton Neurosci 2006; 126-127:320-31. [PMID: 16603418 DOI: 10.1016/j.autneu.2006.01.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Accepted: 01/30/2006] [Indexed: 10/24/2022]
Abstract
Breathing is a vital, rhythmic motor act that is required for blood oxygenation and oxygen delivery to the whole body. Therefore, the brainstem network responsible for the elaboration of the respiratory rhythm must function from the very first moments of extrauterine life. In this review, it is shown that the brainstem noradrenergic system plays a pivotal role in both the modulation and the maturation of the respiratory rhythm generator. Compelling evidence are reported demonstrating that genetically induced alterations of the noradrenergic system in mice affect the prenatal maturation and the perinatal function of the respiratory rhythm generator and have drastic consequences on postnatal survival. Sudden Infant Death Syndrome (SIDS), the leader cause of infant death in industrialised countries, may result from cardiorespiratory disorders during sleep. As several cases of SIDS have been observed in infants having noradrenergic deficits, a possible link between prenatal alteration of the noradrenergic system, altered maturation and function of the respiratory network and SIDS is suggested.
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Affiliation(s)
- Gérard Hilaire
- Groupe d'étude des Réseaux Moteurs, FRE CNRS 2722, 280 boulevard Sainte Marguerite, 13009 Marseille, France.
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Nattie E, Li A. Central chemoreception 2005: A brief review. Auton Neurosci 2006; 126-127:332-8. [PMID: 16581308 DOI: 10.1016/j.autneu.2006.02.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Accepted: 02/06/2006] [Indexed: 10/24/2022]
Abstract
This brief review will place recent findings on specific neurons and receptors identified as putative central chemoreceptors, namely glutamatergic and serotonergic neurons and purogenic receptors, into the context of our working hypothesis that central chemoreception is a distributed property.
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Affiliation(s)
- Eugene Nattie
- Department of Physiology, Borwell Bldg., Dartmouth Medical School, Lebanon, NH 03756-0001, USA.
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Day TA, Wilson RJA. Specific carotid body chemostimulation is sufficient to elicit phrenic poststimulus frequency decline in a novel in situ dual-perfused rat preparation. Am J Physiol Regul Integr Comp Physiol 2005; 289:R532-R544. [PMID: 15802555 DOI: 10.1152/ajpregu.00812.2004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Time-dependent ventilatory responses to hypoxic and hypercapnic challenges, such as posthypoxic frequency decline (PHxFD) and posthypercapnic frequency decline (PHcFD), could profoundly affect breathing stability. However, little is known about the mechanisms that mediate these phenomena. To determine the contribution of specific carotid body chemostimuli to PHxFD and PHcFD, we developed a novel in situ arterially perfused, vagotomized, decerebrate rat preparation in which central and peripheral chemoreceptors are perfused separately (i.e., a nonanesthetized in situ dual perfused preparation). We confirmed that 1) the perfusion of central and peripheral chemoreceptor compartments was independent by applying specific carotid body hypoxia and hypercapnia before and after carotid sinus nerve transection, 2) the PCO(2) chemoresponse of the dual perfused preparation was similar to other decerebrate preparations, and 3) the phrenic output was stable enough to allow investigation of time-dependent phenomena. We then applied four 5-min bouts (separated by 5 min) of specific carotid body hypoxia (40 Torr PO(2) and 40 Torr PCO(2)) or hypercapnia (100 Torr PO(2) and 60 Torr PCO(2)) while holding the brain stem PO(2) and PCO(2) constant. We report the novel finding that specific carotid body chemostimuli were sufficient to elicit several phrenic time-dependent phenomena in the rat. Hypoxic challenges elicited PHxFD that increased with bout, leading to progressive augmentation of the phrenic response. Conversely, hypercapnia elicited short-term depression and PHcFD, neither of which was bout dependent. These results, placed in the context of previous findings, suggest multiple physiological mechanisms are responsible for PHxFD and PHcFD, a redundancy that may illustrate that these phenomena have significant adaptive advantages.
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Affiliation(s)
- Trevor A Day
- Dept. of Physiology and Biophysics, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1
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