1
|
Whitaker-Fornek JR, Nelson JK, Pilarski JQ. Chloride Modulates Central pH Sensitivity and Plasticity of Brainstem Breathing-Related Biorhythms in Zebra Finch Embryos. Dev Psychobiol 2024; 66:e22518. [PMID: 38924086 PMCID: PMC11210689 DOI: 10.1002/dev.22518] [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: 08/31/2023] [Revised: 05/26/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024]
Abstract
All terrestrial vertebrate life must transition from aquatic gas exchange in the embryonic environment to aerial or pulmonary respiration at birth. In addition to being able to breathe air, neonates must possess functional sensory feedback systems for maintaining acid-base balance. Respiratory neurons in the brainstem act as pH sensors that can adjust breathing to regulate systemic pH. The central pH sensitivity of breathing-related motor output develops over the embryonic period in the zebra finch (Taeniopygia guttata). Due to the key role of chloride ions in electrochemical stability and developmental plasticity, we tested chloride's role in the development of central pH sensitivity. We blocked gamma-aminobutyric acid-A receptors and cation-chloride cotransport that subtly modulated the low-pH effects on early breathing biorhythms. Further, chloride-free artificial cerebrospinal fluid altered the pattern and timing of breathing biorhythms and blocked the stimulating effect of acidosis in E12-14 brainstems. Early and middle stage embryos exhibited rebound plasticity in brainstem motor outputs during low-pH treatment, which was eliminated by chloride-free solution. Results show that chloride modulates low-pH sensitivity and rebound plasticity in the zebra finch embryonic brainstem, but work is needed to determine the cellular and circuit mechanisms that control functional chloride balance during acid-base disturbances.
Collapse
Affiliation(s)
| | - Jennie K. Nelson
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho
| | - Jason Q. Pilarski
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho
- Department of Dental Sciences, Idaho State University, Pocatello, Idaho
| |
Collapse
|
2
|
Taylor CE, Mendenhall LE, Sunshine MD, Wilson JN, Calulot CM, Sun RC, Johnson LA, Alilain WJ. Sex and APOE genotype influence respiratory function under hypoxic and hypoxic-hypercapnic conditions. J Neurophysiol 2024; 132:23-33. [PMID: 38748407 DOI: 10.1152/jn.00255.2023] [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: 06/30/2023] [Revised: 04/12/2024] [Accepted: 05/08/2024] [Indexed: 06/12/2024] Open
Abstract
The apolipoprotein E (APOE) gene has been studied due to its influence on Alzheimer's disease (AD) development and work in an APOE mouse model recently demonstrated impaired respiratory motor plasticity following spinal cord injury (SCI). Individuals with AD often copresent with obstructive sleep apnea (OSA) characterized by cessations in breathing during sleep. Despite the prominence of APOE genotype and sex as factors in AD progression, little is known about the impact of these variables on respiratory control. Ventilation is tightly regulated across many systems, with respiratory rhythm formation occurring in the brainstem but modulated in response to chemoreception. Alterations within these modulatory systems may result in disruptions of appropriate respiratory control and ultimately, disease. Using mice expressing two different humanized APOE alleles, we characterized how sex and the presence of APOE3 or APOE4 influences ventilation during baseline breathing (normoxia) and during respiratory challenges. We show that sex and APOE genotype influence breathing during hypoxic challenge, which may have clinical implications in the context of AD and OSA. In addition, female mice, while responding robustly to hypoxia, were unable to recover to baseline respiratory levels, emphasizing sex differences in disordered breathing.NEW & NOTEWORTHY This study is the first to use whole body plethysmography (WBP) to measure the impact of APOE alleles on breathing under normoxia and during adverse respiratory challenges in a targeted replacement Alzheimer's model. Both sex and genotype were shown to affect breathing under normoxia, hypoxic challenge, and hypoxic-hypercapnic challenge. This work has important implications regarding the impact of genetics on respiratory control as well as applications pertaining to conditions of disordered breathing including sleep apnea and neurotrauma.
Collapse
Affiliation(s)
- Chase E Taylor
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Laura E Mendenhall
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Michael D Sunshine
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Jessica N Wilson
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Chris M Calulot
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Ramon C Sun
- Department of Biochemistry & Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida, United States
- Department of Biochemistry, University of Florida, Gainesville, Florida, United States
- Center for Advanced Spatial Biomolecule Research, University of Florida, Gainesville, Florida, United States
| | - Lance A Johnson
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States
| | - Warren J Alilain
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
O'Croinin BR, Young DA, Maier LE, van Diepen S, Day TA, Steinback CD. Influence of hypercapnia and hypercapnic hypoxia on the heart rate response to apnea. Physiol Rep 2024; 12:e16054. [PMID: 38872580 PMCID: PMC11176737 DOI: 10.14814/phy2.16054] [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: 03/05/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 06/15/2024] Open
Abstract
We aimed to determine the relative contribution of hypercapnia and hypoxia to the bradycardic response to apneas. We hypothesized that apneas with hypercapnia would cause greater bradycardia than normoxia, similar to the response seen with hypoxia, and that apneas with hypercapnic hypoxia would induce greater bradycardia than hypoxia or hypercapnia alone. Twenty-six healthy participants (12 females; 23 ± 2 years; BMI 24 ± 3 kg/m2) underwent three gas challenges: hypercapnia (+5 torr end tidal partial pressure of CO2 [PETCO2]), hypoxia (50 torr end tidal partial pressure of O2 [PETO2]), and hypercapnic hypoxia (combined hypercapnia and hypoxia), with each condition interspersed with normocapnic normoxia. Heart rate and rhythm, blood pressure, PETCO2, PETO2, and oxygen saturation were measured continuously. Hypercapnic hypoxic apneas induced larger bradycardia (-19 ± 16 bpm) than normocapnic normoxic apneas (-11 ± 15 bpm; p = 0.002), but had a comparable response to hypoxic (-19 ± 15 bpm; p = 0.999) and hypercapnic apneas (-14 ± 14 bpm; p = 0.059). Hypercapnic apneas were not different from normocapnic normoxic apneas (p = 0.134). After removal of the normocapnic normoxic heart rate response, the change in heart rate during hypercapnic hypoxia (-11 ± 16 bpm) was similar to the summed change during hypercapnia+hypoxia (-9 ± 10 bpm; p = 0.485). Only hypoxia contributed to this bradycardic response. Under apneic conditions, the cardiac response is driven by hypoxia.
Collapse
Affiliation(s)
- Benjamin R O'Croinin
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Desmond A Young
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Lauren E Maier
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Sean van Diepen
- Department of Critical Care Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Division of Cardiology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Craig D Steinback
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
5
|
Limper U, Schöneberger L, Shalchian-Tehran P, Hartmann A, Poggenborg J, Annecke T. Management of Neurogenic Respiratory Alkalosis and Concomitant Lactatemia After Resection of a Posterior Fossa Meningioma: A Case Report. A A Pract 2024; 18:e01800. [PMID: 38864528 DOI: 10.1213/xaa.0000000000001800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Central neurogenic hyperventilation (CNH) is a rare disease, caused by chemical or mechanical disturbance of respiratory centers. It is characterized by the absence of extracerebral respiratory stimuli. A woman developed severe respiratory alkalosis and lactatemia after resection of a posterior fossa meningioma despite lack of cardio-respiratory or metabolic alterations. Cerebral computed tomography (cCT) revealed edema of the pontomedullary area. Treatment with mannitol and dexamethasone reestablished normal breathing patterns. Lactatemia was likely due to reduced splanchnic lactate utilization. Intracranial pathologies should be suspected in case of hyperventilation without overt reasons. cCT to confirm edema or ischemia and prompt treatment is suggested.
Collapse
Affiliation(s)
- Ulrich Limper
- From the Department of Anaesthesiology and Critical Care Medicine, Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Department of Cardiovascular Aerospace Medicine, Cologne, Germany
| | - Louisa Schöneberger
- From the Department of Anaesthesiology and Critical Care Medicine, Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| | - Paiman Shalchian-Tehran
- Department of Neurosurgery, Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| | - Alexander Hartmann
- Department of Neurosurgery, Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| | - Jörg Poggenborg
- Department of Radiology, Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| | - Thorsten Annecke
- From the Department of Anaesthesiology and Critical Care Medicine, Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| |
Collapse
|
6
|
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.
Collapse
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.
| |
Collapse
|
7
|
Park H, Lee CH. The Impact of Pulmonary Disorders on Neurological Health (Lung-Brain Axis). Immune Netw 2024; 24:e20. [PMID: 38974208 PMCID: PMC11224666 DOI: 10.4110/in.2024.24.e20] [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: 03/04/2024] [Revised: 04/30/2024] [Accepted: 05/23/2024] [Indexed: 07/09/2024] Open
Abstract
The brain and lungs, vital organs in the body, play essential roles in maintaining overall well-being and survival. These organs interact through complex and sophisticated bi-directional pathways known as the 'lung-brain axis', facilitated by their close proximity and neural connections. Numerous studies have underscored the mediation of the lung-brain axis by inflammatory responses and hypoxia-induced damage, which are pivotal to the progression of both pulmonary and neurological diseases. This review aims to delve into how pulmonary diseases, including acute/chronic airway diseases and pulmonary conditions, can instigate neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. Additionally, we highlight the emerging research on the lung microbiome which, drawing parallels between the gut and lungs in terms of microbiome contents, may play a significant role in modulating brain health. Ultimately, this review paves the way for exciting avenues of future research and therapeutics in addressing respiratory and neurological diseases.
Collapse
Affiliation(s)
- Hongryeol Park
- Department of Tissue Morphogenesis, Max-Planck Institute for Molecular Biomedicine, Muenster 48149, Germany
| | - Chan Hee Lee
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
- Program of Material Science for Medicine and Pharmaceutics, Hallym University, Chuncheon 24252, Korea
| |
Collapse
|
8
|
Walker JJ, Meunier E, Garcia S, Messaoudi B, Mouly AM, Veyrac A, Buonviso N, Courtiol E. State-dependent alteration of respiration in a rat model of Parkinson's disease. Exp Neurol 2024; 375:114740. [PMID: 38395215 DOI: 10.1016/j.expneurol.2024.114740] [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: 11/14/2023] [Revised: 02/06/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
Parkinson's disease (PD) is the second most frequent neurodegenerative disorder. Besides major deficits in motor coordination, patients may also display sensory and cognitive impairments, which are often overlooked despite being inherently part of the PD symptomatology. Amongst those symptoms, respiration, a key mechanism involved in the regulation of multiple physiological and neuronal processes, appears to be altered. Importantly, breathing patterns are highly correlated with the animal's behavioral states. This raises the question of the potential impact of behavioral state on respiration deficits in PD. To answer this question, we first characterized the respiratory parameters in a neurotoxin-induced rat model of PD (6-OHDA) across three different vigilance states: sleep, quiet waking and exploration. We noted a significantly higher respiratory frequency in 6-OHDA rats during quiet waking compared to Sham rats. A higher respiratory amplitude was also observed in 6-OHDA rats during both quiet waking and exploration. No effect of the treatment was noted during sleep. Given the relation between respiration and olfaction and the presence of olfactory deficits in PD patients, we then investigated the odor-evoked sniffing response in PD rats, using an odor habituation/cross-habituation paradigm. No substantial differences were observed in olfactory abilities between the two groups, as assessed through sniffing frequency. These results corroborate the hypothesis that respiratory impairments in 6-OHDA rats are vigilance-dependent. Our results also shed light on the importance of considering the behavioral state as an impacting factor when analyzing respiration.
Collapse
Affiliation(s)
- Jean Jacques Walker
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France.
| | - Estelle Meunier
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France
| | - Samuel Garcia
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France.
| | - Belkacem Messaoudi
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France.
| | - Anne-Marie Mouly
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France.
| | - Alexandra Veyrac
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France.
| | - Nathalie Buonviso
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France.
| | - Emmanuelle Courtiol
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, CMO, Centre Hospitalier Le Vinatier, Bâtiment 452, Neurocampus Michel Jouvet - 95 Bd Pinel, 69675 Bron Cedex, France.
| |
Collapse
|
9
|
Burgess A, Andrews G, Colby KME, Lucas SJE, Sprecher K, Donnelly J, Ainslie PN, Basnet AS, Burgess KR. Loop gain response to increased cerebral blood flow at high altitude. Sleep Breath 2024; 28:763-771. [PMID: 38085496 DOI: 10.1007/s11325-023-02956-4] [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: 06/03/2023] [Revised: 11/09/2023] [Accepted: 11/22/2023] [Indexed: 05/31/2024]
Abstract
PURPOSE To compare loop gain (LG) before and during pharmacological increases in cerebral blood flow (CBF) at high altitude (HA). Loop gain (LG) describes stability of a negative-feedback control system; defining the magnitude of response to a disturbance, such as hyperpnea to an apnea in periodic breathing (PB). "Controller-gain" sensitivity from afferent peripheral (PCR) and central-chemoreceptors (CCR) plays a key role in perpetuating PB. Changes in CBF may have a critical role via effects on central chemo-sensitivity during sleep. METHODS Polysomnography (PSG) was performed on volunteers after administration of I.V. Acetazolamide (ACZ-10mg/kg) + Dobutamine (DOB-2-5 μg/kg/min) to increase CBF (via Duplex-ultrasound). Central sleep apnea (CSA) was measured from NREM sleep. The duty ratio (DR) was calculated as ventilatory duration (s) divided by cycle duration (s) (hyperpnea/hyperpnea + apnea), LG = 2π/(2πDR-sin2πDR). RESULTS A total of 11 volunteers were studied. Compared to placebo-control, ACZ/DOB showed a significant increase in the DR (0.79 ± 0.21 vs 0.52 ± 0.03, P = 0.002) and reduction in LG (1.90 ± 0.23 vs 1.29 ± 0.35, P = 0.0004). ACZ/DOB increased cardiac output (CO) (8.19 ± 2.06 vs 6.58 ± 1.56L/min, P = 0.02) and CBF (718 ± 120 vs 526 ± 110ml/min, P < 0.001). There was no significant change in arterial blood gases, minute ventilation (VE), or hypoxic ventilatory response (HVR). However, there was a reduction of hypercapnic ventilatory response (HCVR) by 29% (5.9 ± 2.7 vs 4.2 ± 2.8 L/min, P = 0.1). CONCLUSION Pharmacological elevation in CBF significantly reduced LG and severity of CSA. We speculate the effect was on HCVR "controller gain," rather than "plant gain," because PaCO2 and VE were unchanged. An effect via reduced circulation time is unlikely, as the respiratory-cycle length did not change.
Collapse
Affiliation(s)
- Andrew Burgess
- Canberra Sleep Clinic, Canberra, Australian Capital Territory, Australia
| | | | | | | | | | | | | | | | - Keith R Burgess
- Peninsula Sleep Clinic, Sydney, NSW, Australia.
- Macquarie University, Sydney, NSW, Australia.
| |
Collapse
|
10
|
Eugenín J, Richerson GB. Editorial: Alternative and expanding views on central respiratory chemoreception in health and disease. Front Physiol 2024; 15:1403768. [PMID: 38645691 PMCID: PMC11026679 DOI: 10.3389/fphys.2024.1403768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 03/26/2024] [Indexed: 04/23/2024] Open
Affiliation(s)
- Jaime Eugenín
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, Chile
| | - George B. Richerson
- Departments of Neurology and Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, United States
| |
Collapse
|
11
|
Souza GMPR, Abbott SBG. Loss-of-function of chemoreceptor neurons in the retrotrapezoid nucleus: What have we learned from it? Respir Physiol Neurobiol 2024; 322:104217. [PMID: 38237884 PMCID: PMC10922619 DOI: 10.1016/j.resp.2024.104217] [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: 10/14/2023] [Revised: 01/11/2024] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
Central respiratory chemoreceptors are cells in the brain that regulate breathing in relation to arterial pH and PCO2. Neurons located at the retrotrapezoid nucleus (RTN) have been hypothesized to be central chemoreceptors and/or to be part of the neural network that drives the central respiratory chemoreflex. The inhibition or ablation of RTN chemoreceptor neurons has offered important insights into the role of these cells on central respiratory chemoreception and the neural control of breathing over almost 60 years since the original identification of acid-sensitive properties of this ventral medullary site. Here, we discuss the current definition of chemoreceptor neurons in the RTN and describe how this definition has evolved over time. We then summarize the results of studies that use loss-of-function approaches to evaluate the effects of disrupting the function of RTN neurons on respiration. These studies offer evidence that RTN neurons are indispensable for the central respiratory chemoreflex in mammals and exert a tonic drive to breathe at rest. Moreover, RTN has an interdependent relationship with oxygen sensing mechanisms for the maintenance of the neural drive to breathe and blood gas homeostasis. Collectively, RTN neurons are a genetically-defined group of putative central respiratory chemoreceptors that generate CO2-dependent drive that supports eupneic breathing and stimulates the hypercapnic ventilatory reflex.
Collapse
|
12
|
Ribeiro LDJA, Bastos VHDV, Coertjens M. Breath-holding as model for the evaluation of EEG signal during respiratory distress. Eur J Appl Physiol 2024; 124:753-760. [PMID: 38105311 DOI: 10.1007/s00421-023-05379-x] [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: 08/08/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023]
Abstract
PURPOSE Research describes the existence of a relationship between cortical activity and the regulation of bulbar respiratory centers through the evaluation of the electroencephalographic (EEG) signal during respiratory challenges. For example, we found evidences of a reduction in the frequency of the EEG (alpha band) in both divers and non-divers during apnea tests. For instance, this reduction was more prominent in divers due to the greater physiological disturbance resulting from longer apnea time. However, little is known about EEG adaptations during tests of maximal apnea, a test that voluntarily stops breathing and induces dyspnea. RESULTS Through this mini-review, we verified that a protocol of successive apneas triggers a significant increase in the maximum apnea time and we hypothesized that successive maximal apnea test could be a powerful model for the study of cortical activity during respiratory distress. CONCLUSION Dyspnea is a multifactorial symptom and we believe that performing a successive maximal apnea protocol is possible to understand some factors that determine the sensation of dyspnea through the EEG signal, especially in people not trained in apnea.
Collapse
Affiliation(s)
- Lucas de Jesus Alves Ribeiro
- Physiotherapy Department, Universidade Federal do Delta do Parnaíba, Av. São Sebastião, CEP: 64.202-020, Parnaíba, PI, 2819, Brazil
- Brain Mapping and Functionality Laboratory, Universidade Federal do Delta do Parnaíba, Piauí, Brazil
| | - Victor Hugo do Vale Bastos
- Physiotherapy Department, Universidade Federal do Delta do Parnaíba, Av. São Sebastião, CEP: 64.202-020, Parnaíba, PI, 2819, Brazil
- Postgraduate Program in Biomedical Sciences, Universidade Federal do Delta do Parnaíba, Piauí, Brazil
- Brain Mapping and Functionality Laboratory, Universidade Federal do Delta do Parnaíba, Piauí, Brazil
| | - Marcelo Coertjens
- Physiotherapy Department, Universidade Federal do Delta do Parnaíba, Av. São Sebastião, CEP: 64.202-020, Parnaíba, PI, 2819, Brazil.
- Postgraduate Program in Biomedical Sciences, Universidade Federal do Delta do Parnaíba, Piauí, Brazil.
| |
Collapse
|
13
|
Cummings KJ, Leiter JC, Trachtenberg FL, Okaty BW, Darnall RA, Haas EA, Harper RM, Nattie EE, Krous HF, Mena OJ, Richerson GB, Dymecki SM, Kinney HC, Haynes RL. Altered 5-HT2A/C receptor binding in the medulla oblongata in the sudden infant death syndrome (SIDS): Part II. Age-associated alterations in serotonin receptor binding profiles within medullary nuclei supporting cardiorespiratory homeostasis. J Neuropathol Exp Neurol 2024; 83:144-160. [PMID: 38323418 PMCID: PMC10880067 DOI: 10.1093/jnen/nlae004] [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] [Indexed: 02/08/2024] Open
Abstract
The failure of chemoreflexes, arousal, and/or autoresuscitation to asphyxia may underlie some sudden infant death syndrome (SIDS) cases. In Part I, we showed that some SIDS infants had altered 5-hydroxytryptamine (5-HT)2A/C receptor binding in medullary nuclei supporting chemoreflexes, arousal, and autoresuscitation. Here, using the same dataset, we tested the hypotheses that the prevalence of low 5-HT1A and/or 5-HT2A/C receptor binding (defined as levels below the 95% confidence interval of controls-a new approach), and the percentages of nuclei affected are greater in SIDS versus controls, and that the distribution of low binding varied with age of death. The prevalence and percentage of nuclei with low 5-HT1A and 5-HT2A/C binding in SIDS were twice that of controls. The percentage of nuclei with low 5-HT2A/C binding was greater in older SIDS infants. In >80% of older SIDS infants, low 5-HT2A/C binding characterized the hypoglossal nucleus, vagal dorsal nucleus, nucleus of solitary tract, and nuclei of the olivocerebellar subnetwork (important for blood pressure regulation). Together, our findings from SIDS infants and from animal models of serotonergic dysfunction suggest that some SIDS cases represent a serotonopathy. We present new hypotheses, yet to be tested, about how defects within serotonergic subnetworks may lead to SIDS.
Collapse
Affiliation(s)
- Kevin J Cummings
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - James C Leiter
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | | | - Benjamin W Okaty
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert A Darnall
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Elisabeth A Haas
- Department of Research, Rady’s Children’s Hospital, San Diego, California, USA
| | - Ronald M Harper
- Department of Neurobiology and the Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Eugene E Nattie
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Henry F Krous
- Department of Pediatrics, University of California San Diego, San Diego, California, USA
- Departments of Pathology and Pediatrics, Rady Children’s Hospital, San Diego, California, USA
| | - Othon J Mena
- San Diego County Medical Examiner Office, San Diego, California, USA
| | - George B Richerson
- Departments of Neurology and Molecular Physiology & Biophysics, University of Iowa, Iowa City, Iowa, USA
| | - Susan M Dymecki
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Hannah C Kinney
- Department of Pathology, CJ Murphy Laboratory for SIDS Research, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Robin L Haynes
- Department of Pathology, CJ Murphy Laboratory for SIDS Research, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
14
|
Díaz-Jara E, Pereyra K, Vicencio S, Olesen MA, Schwarz KG, Toledo C, Díaz HS, Quintanilla RA, Del Rio R. Superoxide dismutase 2 deficiency is associated with enhanced central chemoreception in mice: Implications for breathing regulation. Redox Biol 2024; 69:102992. [PMID: 38142585 PMCID: PMC10788617 DOI: 10.1016/j.redox.2023.102992] [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: 10/30/2023] [Accepted: 12/07/2023] [Indexed: 12/26/2023] Open
Abstract
AIMS In mammals, central chemoreception plays a crucial role in the regulation of breathing function in both health and disease conditions. Recently, a correlation between high levels of superoxide anion (O2.-) in the Retrotrapezoid nucleus (RTN), a main brain chemoreceptor area, and enhanced central chemoreception has been found in rodents. Interestingly, deficiency in superoxide dismutase 2 (SOD2) expression, a pivotal antioxidant enzyme, has been linked to the development/progression of several diseases. Despite, the contribution of SOD2 on O2.- regulation on central chemoreceptor function is unknown. Accordingly, we sought to determine the impact of partial deletion of SOD2 expression on i) O2.-accumulation in the RTN, ii) central ventilatory chemoreflex function, and iii) disordered-breathing. Finally, we study cellular localization of SOD2 in the RTN of healthy mice. METHODS Central chemoreflex drive and breathing function were assessed in freely moving heterozygous SOD2 knockout mice (SOD2+/- mice) and age-matched control wild type (WT) mice by whole-body plethysmography. O2.- levels were determined in RTN brainstem sections and brain isolated mitochondria, while SOD2 protein expression and tissue localization were determined by immunoblot, RNAseq and immunofluorescent staining, respectively. RESULTS Our results showed that SOD2+/- mice displayed reductions in SOD2 levels and high O2.- formation and mitochondrial dysfunction within the RTN compared to WT. Additionally, SOD2+/- mice displayed a heightened ventilatory response to hypercapnia and exhibited overt signs of altered breathing patterns. Both, RNAseq analysis and immunofluorescence co-localization studies showed that SOD2 expression was confined to RTN astrocytes but not to RTN chemoreceptor neurons. Finally, we found that SOD2+/- mice displayed alterations in RTN astrocyte morphology compared to RTN astrocytes from WT mice. INNOVATION & CONCLUSION These findings provide first evidence of the role of SOD2 in the regulation of O2.- levels in the RTN and its potential contribution on the regulation of central chemoreflex function. Our results suggest that reductions in the expression of SOD2 in the brain may contribute to increase O2.- levels in the RTN being the outcome a chronic surge in central chemoreflex drive and the development/maintenance of altered breathing patterns. Overall, dysregulation of SOD2 and the resulting increase in O2.- levels in brainstem respiratory areas can disrupt normal respiratory control mechanisms and contribute to breathing dysfunction seen in certain disease conditions characterized by high oxidative stress.
Collapse
Affiliation(s)
- Esteban Díaz-Jara
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Katherine Pereyra
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Sinay Vicencio
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Margrethe A Olesen
- Laboratory of Neurodegenerative Diseases, Universidad Autónoma de Chile, Santiago, Chile.
| | - Karla G Schwarz
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile; Institute of Physiology, Universidad Austral de Chile, Valdivia, Chile.
| | - Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Rodrigo A Quintanilla
- Laboratory of Neurodegenerative Diseases, Universidad Autónoma de Chile, Santiago, Chile.
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile; Department of Cell Biology and Physiology, School of Medicine, University of Kansas Medical Center, Kansas City, KS, United States.
| |
Collapse
|
15
|
Aung O, Amorim MR, Mendelowitz D, Polotsky VY. Revisiting the Role of Serotonin in Sleep-Disordered Breathing. Int J Mol Sci 2024; 25:1483. [PMID: 38338762 PMCID: PMC10855456 DOI: 10.3390/ijms25031483] [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: 12/12/2023] [Revised: 01/22/2024] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
Serotonin or 5-hydroxytryptamine (5-HT) is a ubiquitous neuro-modulator-transmitter that acts in the central nervous system, playing a major role in the control of breathing and other physiological functions. The midbrain, pons, and medulla regions contain several serotonergic nuclei with distinct physiological roles, including regulating the hypercapnic ventilatory response, upper airway patency, and sleep-wake states. Obesity is a major risk factor in the development of sleep-disordered breathing (SDB), such as obstructive sleep apnea (OSA), recurrent closure of the upper airway during sleep, and obesity hypoventilation syndrome (OHS), a condition characterized by daytime hypercapnia and hypoventilation during sleep. Approximately 936 million adults have OSA, and 32 million have OHS worldwide. 5-HT acts on 5-HT receptor subtypes that modulate neural control of breathing and upper airway patency. This article reviews the role of 5-HT in SDB and the current advances in 5-HT-targeted treatments for SDB.
Collapse
Affiliation(s)
- O Aung
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA; (O.A.); (M.R.A.)
- Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Anesthesiology and Critical Care Medicine, George Washington University, Washington, DC 20037, USA
| | - Mateus R. Amorim
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA; (O.A.); (M.R.A.)
- Department of Anesthesiology and Critical Care Medicine, George Washington University, Washington, DC 20037, USA
| | - David Mendelowitz
- Department of Pharmacology and Physiology, George Washington University, Washington, DC 20037, USA;
| | - Vsevolod Y. Polotsky
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA; (O.A.); (M.R.A.)
- Department of Anesthesiology and Critical Care Medicine, George Washington University, Washington, DC 20037, USA
- Department of Pharmacology and Physiology, George Washington University, Washington, DC 20037, USA;
| |
Collapse
|
16
|
Moreira TS, Mulkey DK, Takakura AC. Update on vascular control of central chemoreceptors. Exp Physiol 2023. [PMID: 38153366 DOI: 10.1113/ep091329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/11/2023] [Indexed: 12/29/2023]
Abstract
At least four mechanisms have been proposed to elucidate how neurons in the retrotrapezoid (RTN) region sense changes in CO2 /H+ to regulate breathing (i.e., function as respiratory chemosensors). These mechanisms include: (1) intrinsic neuronal sensitivity to H+ mediated by TASK-2 and GPR4; (2) paracrine activation of RTN neurons by CO2 -responsive astrocytes (via a purinergic mechanism); (3) enhanced excitatory synaptic input or disinhibition; and (4) CO2 -induced vascular contraction. Although blood flow can influence tissue CO2 /H+ levels, there is limited understanding of how control of vascular tone in central CO2 chemosensitive regions might contribute to respiratory output. In this review, we focus on recent evidence that CO2 /H+ -induced purinergic-dependent vasoconstriction in the ventral parafacial region near RTN neurons supports respiratory chemoreception. This mechanism appears to be unique to the ventral parafacial region and opposite to other brain regions, including medullary chemosensor regions, where CO2 /H+ elicits vasodilatation. We speculate that this mechanism helps to maintain CO2 /H+ levels in the vicinity of RTN neurons, thereby maintaining the drive to breathe. Important next steps include determining whether disruption of CO2 /H+ vascular reactivity contributes to or can be targeted to improve breathing problems in disease states, such as Parkinson's disease.
Collapse
Affiliation(s)
- Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
| |
Collapse
|
17
|
Ahmadzadeh E, Dudink I, Walker DW, Sutherland AE, Pham Y, Stojanovska V, Polglase GR, Miller SL, Allison BJ. The medullary serotonergic centres involved in cardiorespiratory control are disrupted by fetal growth restriction. J Physiol 2023. [PMID: 37641535 DOI: 10.1113/jp284971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023] Open
Abstract
Fetal growth restriction (FGR) is associated with cardiovascular and respiratory complications after birth and beyond. Despite research showing a range of neurological changes following FGR, little is known about how FGR affects the brainstem cardiorespiratory control centres. The primary neurons that release serotonin reside in the brainstem cardiorespiratory control centres and may be affected by FGR. At two time points in the last trimester of sheep brain development, 110 and 127 days of gestation (0.74 and 0.86 of gestation), we assessed histopathological alterations in the brainstem cardiorespiratory control centres of the pons and medulla in early-onset FGR versus control fetal sheep. The FGR cohort were hypoxaemic and asymmetrically growth restricted. Compared to the controls, the brainstem of FGR fetuses exhibited signs of neuropathology, including elevated cell death and reduced cell proliferation, grey and white matter deficits, and evidence of oxidative stress and neuroinflammation. FGR brainstem pathology was predominantly observed in the medullary raphé nuclei, hypoglossal nucleus, nucleus ambiguous, solitary tract and nucleus of the solitary tract. The FGR groups showed imbalanced brainstem serotonin and serotonin 1A receptor abundance in the medullary raphé nuclei, despite evidence of increased serotonin staining within vascular regions of placentomes collected from FGR fetuses. Our findings demonstrate both early and adaptive brainstem neuropathology in response to placental insufficiency. KEY POINTS: Early-onset fetal growth restriction (FGR) was induced in fetal sheep, resulting in chronic fetal hypoxaemia. Growth-restricted fetuses exhibit persistent neuropathology in brainstem nuclei, characterised by disrupted cell proliferation and reduced neuronal cell number within critical centres responsible for the regulation of cardiovascular and respiratory functions. Elevated brainstem inflammation and oxidative stress suggest potential mechanisms contributing to the observed neuropathological changes. Both placental and brainstem levels of 5-HT were found to be impaired following FGR.
Collapse
Affiliation(s)
- Elham Ahmadzadeh
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Ingrid Dudink
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - David W Walker
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Amy E Sutherland
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Yen Pham
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Beth J Allison
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
18
|
Souza GMPR, Stornetta DS, Shi Y, Lim E, Berry FE, Bayliss DA, Abbott SBG. Neuromedin B-Expressing Neurons in the Retrotrapezoid Nucleus Regulate Respiratory Homeostasis and Promote Stable Breathing in Adult Mice. J Neurosci 2023; 43:5501-5520. [PMID: 37290937 PMCID: PMC10376939 DOI: 10.1523/jneurosci.0386-23.2023] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/10/2023] Open
Abstract
Respiratory chemoreceptor activity encoding arterial Pco2 and Po2 is a critical determinant of ventilation. Currently, the relative importance of several putative chemoreceptor mechanisms for maintaining eupneic breathing and respiratory homeostasis is debated. Transcriptomic and anatomic evidence suggests that bombesin-related peptide Neuromedin-B (Nmb) expression identifies chemoreceptor neurons in the retrotrapezoid nucleus (RTN) that mediate the hypercapnic ventilatory response, but functional support is missing. In this study, we generated a transgenic Nmb-Cre mouse and used Cre-dependent cell ablation and optogenetics to test the hypothesis that RTN Nmb neurons are necessary for the CO2-dependent drive to breathe in adult male and female mice. Selective ablation of ∼95% of RTN Nmb neurons causes compensated respiratory acidosis because of alveolar hypoventilation, as well as profound breathing instability and respiratory-related sleep disruption. Following RTN Nmb lesion, mice were hypoxemic at rest and were prone to severe apneas during hyperoxia, suggesting that oxygen-sensitive mechanisms, presumably the peripheral chemoreceptors, compensate for the loss of RTN Nmb neurons. Interestingly, ventilation following RTN Nmb -lesion was unresponsive to hypercapnia, but behavioral responses to CO2 (freezing and avoidance) and the hypoxia ventilatory response were preserved. Neuroanatomical mapping shows that RTN Nmb neurons are highly collateralized and innervate the respiratory-related centers in the pons and medulla with a strong ipsilateral preference. Together, this evidence suggests that RTN Nmb neurons are dedicated to the respiratory effects of arterial Pco2/pH and maintain respiratory homeostasis in intact conditions and suggest that malfunction of these neurons could underlie the etiology of certain forms of sleep-disordered breathing in humans.SIGNIFICANCE STATEMENT Respiratory chemoreceptors stimulate neural respiratory motor output to regulate arterial Pco2 and Po2, thereby maintaining optimal gas exchange. Neurons in the retrotrapezoid nucleus (RTN) that express the bombesin-related peptide Neuromedin-B are proposed to be important in this process, but functional evidence has not been established. Here, we developed a transgenic mouse model and demonstrated that RTN neurons are fundamental for respiratory homeostasis and mediate the stimulatory effects of CO2 on breathing. Our functional and anatomic data indicate that Nmb-expressing RTN neurons are an integral component of the neural mechanisms that mediate CO2-dependent drive to breathe and maintain alveolar ventilation. This work highlights the importance of the interdependent and dynamic integration of CO2- and O2-sensing mechanisms in respiratory homeostasis of mammals.
Collapse
Affiliation(s)
- George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Eunu Lim
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Faye E Berry
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| |
Collapse
|
19
|
Tubek S, Niewinski P, Langner-Hetmanczuk A, Jura M, Kuliczkowski W, Reczuch K, Ponikowski P. The effects of P2Y 12 adenosine receptors' inhibitors on central and peripheral chemoreflexes. Front Physiol 2023; 14:1214893. [PMID: 37538377 PMCID: PMC10394699 DOI: 10.3389/fphys.2023.1214893] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/30/2023] [Indexed: 08/05/2023] Open
Abstract
Introduction: The most common side effect of ticagrelor is dyspnea, which leads to premature withdrawal of this life-saving medication in 6.5% of patients. Increased chemoreceptors' sensitivity was suggested as a possible pathophysiological explanation of this phenomenon; however, the link between oversensitization of peripheral and/or central chemosensory areas and ticagrelor intake has not been conclusively proved. Methods: We measured peripheral chemoreceptors' sensitivity using hypoxic ventilatory response (HVR), central chemoreceptors' sensitivity using hypercapnic hyperoxic ventilatory response (HCVR), and dyspnea severity before and 4 ± 1 weeks following ticagrelor initiation in 11 subjects with chronic coronary syndrome undergoing percutaneous coronary intervention (PCI). The same tests were performed in 11 age-, sex-, and BMI-matched patients treated with clopidogrel. The study is registered at ClinicalTrials.com at NCT05080478. Results: Ticagrelor significantly increased both HVR (0.52 ± 0.46 vs. 0.84 ± 0.69 L min-1 %-1; p < 0.01) and HCVR (1.05 ± 0.64 vs. 1.75 ± 1.04 L min-1 mmHg-1; p < 0.01). The absolute change in HVR correlated with the change in HCVR. Clopidogrel administration did not significantly influence HVR (0.63 ± 0.32 vs. 0.58 ± 0.33 L min-1%-1; p = 0.53) and HCVR (1.22 ± 0.67 vs. 1.2 ± 0.64 L min-1 mmHg-1; p = 0.79). Drug-related dyspnea was reported by three subjects in the ticagrelor group and by none in the clopidogrel group. These patients were characterized by either high baseline HVR and HCVR or excessive increase in HVR following ticagrelor initiation. Discussion: Ticagrelor, contrary to clopidogrel, sensitizes both peripheral and central facets of chemodetection. Two potential mechanisms of ticagrelor-induced dyspnea have been identified: 1) high baseline HVR and HCVR or 2) excessive increase in HVR or HVR and HCVR. Whether other patterns of changes in chemosensitivities play a role in the pathogenesis of this phenomenon needs to be further investigated.
Collapse
Affiliation(s)
- Stanislaw Tubek
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Piotr Niewinski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Anna Langner-Hetmanczuk
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Maksym Jura
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
- Department of Physiology, Wroclaw Medical University, Wroclaw, Poland
| | - Wiktor Kuliczkowski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Krzysztof Reczuch
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| | - Piotr Ponikowski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, Wroclaw, Poland
| |
Collapse
|
20
|
Phelan DE, Mota C, Strowitzki MJ, Shigemura M, Sznajder JI, Crowe L, Masterson JC, Hayes SE, Reddan B, Yin X, Brennan L, Crean D, Cummins EP. Hypercapnia alters mitochondrial gene expression and acylcarnitine production in monocytes. Immunol Cell Biol 2023; 101:556-577. [PMID: 36967673 PMCID: PMC10330468 DOI: 10.1111/imcb.12642] [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: 08/12/2022] [Revised: 03/03/2023] [Accepted: 03/25/2023] [Indexed: 03/29/2023]
Abstract
CO2 is produced during aerobic respiration. Normally, levels of CO2 in the blood are tightly regulated but pCO2 can rise (hypercapnia, pCO2 > 45 mmHg) in patients with lung diseases, for example, chronic obstructive pulmonary disease (COPD). Hypercapnia is a risk factor in COPD but may be of benefit in the context of destructive inflammation. The effects of CO2 per se, on transcription, independent of pH change are poorly understood and warrant further investigation. Here we elucidate the influence of hypercapnia on monocytes and macrophages through integration of state-of-the-art RNA-sequencing, metabolic and metabolomic approaches. THP-1 monocytes and interleukin 4-polarized primary murine macrophages were exposed to 5% CO2 versus 10% CO2 for up to 24 h in pH-buffered conditions. In hypercapnia, we identified around 370 differentially expressed genes (DEGs) under basal and about 1889 DEGs under lipopolysaccharide-stimulated conditions in monocytes. Transcripts relating to both mitochondrial and nuclear-encoded gene expression were enhanced in hypercapnia in basal and lipopolysaccharide-stimulated cells. Mitochondrial DNA content was not enhanced, but acylcarnitine species and genes associated with fatty acid metabolism were increased in hypercapnia. Primary macrophages exposed to hypercapnia also increased activation of genes associated with fatty acid metabolism and reduced activation of genes associated with glycolysis. Thus, hypercapnia elicits metabolic shifts in lipid metabolism in monocytes and macrophages under pH-buffered conditions. These data indicate that CO2 is an important modulator of monocyte transcription that can influence immunometabolic signaling in immune cells in hypercapnia. These immunometabolic insights may be of benefit in the treatment of patients experiencing hypercapnia.
Collapse
Affiliation(s)
- David E Phelan
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Catarina Mota
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Moritz J Strowitzki
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Masahiko Shigemura
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Louise Crowe
- Allergy, Inflammation & Remodeling Research Laboratory, Kathleen Lonsdale Institute for Human Health Research, Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Joanne C Masterson
- Allergy, Inflammation & Remodeling Research Laboratory, Kathleen Lonsdale Institute for Human Health Research, Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Sophie E Hayes
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Ben Reddan
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Xiaofei Yin
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Lorraine Brennan
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Daniel Crean
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Eoin P Cummins
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| |
Collapse
|
21
|
Stewart JM, Medow MS. Anticipatory central command on standing decreases cerebral blood velocity causing hypocapnia in hyperpneic postural tachycardia syndrome. J Appl Physiol (1985) 2023; 135:26-34. [PMID: 37227184 PMCID: PMC10281786 DOI: 10.1152/japplphysiol.00016.2023] [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: 01/10/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 05/26/2023] Open
Abstract
Fifty percent of patients with postural tachycardia syndrome (POTS) are hypocapnic during orthostasis related to initial orthostatic hypotension (iOH). We determined whether iOH drives hypocapnia in POTS by low BP or decreased cerebral blood velocity (CBv). We studied three groups; healthy volunteers (n = 32, 18 ± 3 yr) were compared with POTS, grouped by presence [POTS-low end-tidal CO2 (↓ETCO2), n = 26, 19 ± 2 yr] or absence [POTS-normal upright end-tidal carbon dioxide (nlCO2), n = 28, 19 ± 3 yr] of standing hypocapnia defined by end-tidal CO2 (ETCO2) ≤ 30 mmHg at steady-state, measuring middle cerebral artery CBv, heart rate (HR), and beat-to-beat blood pressure (BP). After 30 min supine, subjects stood for 5 min. Quantities were measured prestanding, at minimum CBv, minimum BP, peak HR, CBv recovery, BP recovery, minimum HR, steady-state, and 5 min. Baroreflex gain was estimated by α index. iOH occurred with similar frequency and minimum BP in POTS-↓ETCO2 and POTS-nlCO2. Minimum CBv was reduced significantly (P < 0.05) in POTS-↓ETCO2 (48 ± 3 cm/s) preceding hypocapnia compared with POTS-nlCO2 (61 ± 3 cm/s) or Control (60 ± 2 cm/s). The anticipatory increased BP was significantly larger (P < 0.05) in POTS (8 ± 1 mmHg vs. 2 ± 1) and began ∼8 s prestanding. HR increased in all subjects, CBv increased significantly (P < 0.05) in both POTS-nlCO2 (76 ± 2 to 85 ± 2 cm/s) and Control (75 ± 2 to 80 ± 2 cm/s) consistent with central command. CBv decreased in POTS-↓ETCO2 (76 ± 3 to 64 ± 3 cm/s) correlating with decreased baroreflex gain. Cerebral conductance [meanCBv/mean arterial blood pressure (MAP)] was reduced in POTS-↓ETCO2 throughout. Data support the hypothesis that excessively reduced CBv during iOH may intermittently reduce carotid body blood flow, sensitizing that organ and producing postural hyperventilation in POTS-↓ETCO2. Excessive fall in CBv occurs in part during prestanding central command and is a facet of defective parasympathetic regulation in POTS.NEW & NOTEWORTHY Dyspnea is frequent in postural tachycardia syndrome (POTS) and is associated with upright hyperpnea and hypocapnia that drives sinus tachycardia. It is initiated by an exaggerated reduction in cerebral conductance and decreased cerebral blood flow (CBF) that precedes the act of standing. This is a form of autonomically mediated "central command." Cerebral blood flow is further reduced by initial orthostatic hypotension common in POTS. Hypocapnia is maintained during the standing response and might account for persistent postural tachycardia.
Collapse
Affiliation(s)
- Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, New York, United States
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Marvin S Medow
- Department of Pediatrics, New York Medical College, Valhalla, New York, United States
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| |
Collapse
|
22
|
Brady CT, Marshall A, Zhang C, Parker MD. NBCe1-B/C-knockout mice exhibit an impaired respiratory response and an enhanced renal response to metabolic acidosis. Front Physiol 2023; 14:1201034. [PMID: 37405134 PMCID: PMC10315466 DOI: 10.3389/fphys.2023.1201034] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 06/07/2023] [Indexed: 07/06/2023] Open
Abstract
The sodium-bicarbonate cotransporter (NBCe1) has three primary variants: NBCe1-A, -B and -C. NBCe1-A is expressed in renal proximal tubules in the cortical labyrinth, where it is essential for reclaiming filtered bicarbonate, such that NBCe1-A knockout mice are congenitally acidemic. NBCe1-B and -C variants are expressed in chemosensitive regions of the brainstem, while NBCe1-B is also expressed in renal proximal tubules located in the outer medulla. Although mice lacking NBCe1-B/C (KOb/c) exhibit a normal plasma pH at baseline, the distribution of NBCe1-B/C indicates that these variants could play a role in both the rapid respiratory and slower renal responses to metabolic acidosis (MAc). Therefore, in this study we used an integrative physiologic approach to investigate the response of KOb/c mice to MAc. By means of unanesthetized whole-body plethysmography and blood-gas analysis, we demonstrate that the respiratory response to MAc (increase in minute volume, decrease in pCO2) is impaired in KOb/c mice leading to a greater severity of acidemia after 1 day of MAc. Despite this respiratory impairment, the recovery of plasma pH after 3-days of MAc remained intact in KOb/c mice. Using data gathered from mice housed in metabolic cages we demonstrate a greater elevation of renal ammonium excretion and greater downregulation of the ammonia recycling enzyme glutamine synthetase in KOb/c mice on day 2 of MAc, consistent with greater renal acid-excretion. We conclude that KOb/c mice are ultimately able to defend plasma pH during MAc, but that the integrated response is disturbed such that the burden of work shifts from the respiratory system to the kidneys, delaying the recovery of pH.
Collapse
Affiliation(s)
- Clayton T. Brady
- Jacobs School of Medicine and Biomedical Sciences, Department of Physiology and Biophysics, The State University of New York: The University at Buffalo, Buffalo, NY, United States
| | - Aniko Marshall
- Jacobs School of Medicine and Biomedical Sciences, Department of Physiology and Biophysics, The State University of New York: The University at Buffalo, Buffalo, NY, United States
| | - Chen Zhang
- Jacobs School of Medicine and Biomedical Sciences, Department of Physiology and Biophysics, The State University of New York: The University at Buffalo, Buffalo, NY, United States
- Department of Biological Sciences, The State University of New York: The University at Buffalo, Buffalo, NY, United States
| | - Mark D. Parker
- Jacobs School of Medicine and Biomedical Sciences, Department of Physiology and Biophysics, The State University of New York: The University at Buffalo, Buffalo, NY, United States
- Jacobs School of Medicine and Biomedical Sciences, Department of Ophthalmology, The State University of New York: The University at Buffalo, Buffalo, NY, United States
| |
Collapse
|
23
|
Yegen CH, Marchant D, Bernaudin JF, Planes C, Boncoeur E, Voituron N. Chronic pulmonary fibrosis alters the functioning of the respiratory neural network. Front Physiol 2023; 14:1205924. [PMID: 37383147 PMCID: PMC10293840 DOI: 10.3389/fphys.2023.1205924] [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: 04/14/2023] [Accepted: 06/02/2023] [Indexed: 06/30/2023] Open
Abstract
Some patients with idiopathic pulmonary fibrosis present impaired ventilatory variables characterised by low forced vital capacity values associated with an increase in respiratory rate and a decrease in tidal volume which could be related to the increased pulmonary stiffness. The lung stiffness observed in pulmonary fibrosis may also have an effect on the functioning of the brainstem respiratory neural network, which could ultimately reinforce or accentuate ventilatory alterations. To this end, we sought to uncover the consequences of pulmonary fibrosis on ventilatory variables and how the modification of pulmonary rigidity could influence the functioning of the respiratory neuronal network. In a mouse model of pulmonary fibrosis obtained by 6 repeated intratracheal instillations of bleomycin (BLM), we first observed an increase in minute ventilation characterised by an increase in respiratory rate and tidal volume, a desaturation and a decrease in lung compliance. The changes in these ventilatory variables were correlated with the severity of the lung injury. The impact of lung fibrosis was also evaluated on the functioning of the medullary areas involved in the elaboration of the central respiratory drive. Thus, BLM-induced pulmonary fibrosis led to a change in the long-term activity of the medullary neuronal respiratory network, especially at the level of the nucleus of the solitary tract, the first central relay of the peripheral afferents, and the Pre-Bötzinger complex, the inspiratory rhythm generator. Our results showed that pulmonary fibrosis induced modifications not only of pulmonary architecture but also of central control of the respiratory neural network.
Collapse
Affiliation(s)
- Céline-Hivda Yegen
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
| | - Dominique Marchant
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
| | - Jean-François Bernaudin
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
- Faculté de Médecine, Sorbonne Université, Paris, France
| | - Carole Planes
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
- Service de Physiologie et d’Explorations Fonctionnelles, Hôpital Avicenne, APHP, Bobigny, France
| | - Emilie Boncoeur
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
| | - Nicolas Voituron
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
- Département STAPS, Université Sorbonne Paris Nord, Bobigny, France
| |
Collapse
|
24
|
Tian QQ, Cheng C, Liu PH, Yin ZX, Zhang MK, Cui YP, Zhao R, Deng H, Lu LM, Tang CZ, Xu NG, Yang XJ, Sun JB, Qin W. Combined effect of transcutaneous auricular vagus nerve stimulation and 0.1 Hz slow-paced breathing on working memory. Front Neurosci 2023; 17:1133964. [PMID: 36968483 PMCID: PMC10034029 DOI: 10.3389/fnins.2023.1133964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 02/22/2023] [Indexed: 03/11/2023] Open
Abstract
BackgroundPrevious research has found that transcutaneous auricular vagus nerve stimulation (taVNS) can improve working memory (WM) performance. It has also been shown that 0.1 Hz slow-paced breathing (SPB, i.e., breathing at a rate of approximately 6 breaths/min) can significantly influence physical state and cognitive function via changes in autonomic afferent activity. In the present study, we investigated the synergistic effects of taVNS and SPB on WM performance.MethodsA total of 96 healthy people participated in this within-subjects experiment involving four conditions, namely taVNS, SPB, combined taVNS with SPB (taVNS + SPB), and sham. Each participant underwent each intervention for 30 min and WM was compared pre- and post-intervention using the spatial and digit n-back tasks in a random order four times. Permutation-based analysis of variance was used to assess the interaction between time and intervention.ResultsFor the spatial 3-back task, a significant interaction between time and intervention was found for the accuracy rate of matching trials (mACC, p = 0.03). Post hoc analysis suggested that both taVNS and taVNS + SPB improved WM performance, however, no significant difference was found in the SPB or sham groups.ConclusionThis study has replicated the effects of taVNS on WM performance reported in previous studies. However, the synergistic effects of combined taVNS and SPB warrant further research.
Collapse
Affiliation(s)
- Qian-Qian Tian
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Chen Cheng
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Peng-Hui Liu
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Zi-Xin Yin
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Meng-Kai Zhang
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Ya-Peng Cui
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Rui Zhao
- School of Electronics and Information, Xi’an Polytechnic University, Xi’an, Shaanxi, China
| | - Hui Deng
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
- Guangzhou Institute of Technology, Xidian University, Xi’an, Shaanxi, China
| | - Li-Ming Lu
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Chun-Zhi Tang
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Neng-Gui Xu
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xue-Juan Yang
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
- Guangzhou Institute of Technology, Xidian University, Xi’an, Shaanxi, China
- Xue-Juan Yang,
| | - Jin-Bo Sun
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
- Guangzhou Institute of Technology, Xidian University, Xi’an, Shaanxi, China
- *Correspondence: Jin-Bo Sun,
| | - Wei Qin
- Intelligent Non-Invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi’an, Shaanxi, China
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi, China
- Guangzhou Institute of Technology, Xidian University, Xi’an, Shaanxi, China
| |
Collapse
|
25
|
Cáceres D, Ochoa M, González-Ortiz M, Bravo K, Eugenín J. Effects of Prenatal Cannabinoids Exposure upon Placenta and Development of Respiratory Neural Circuits. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1428:199-232. [PMID: 37466775 DOI: 10.1007/978-3-031-32554-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Cannabis use has risen dangerously during pregnancy in the face of incipient therapeutic use and a growing perception of safety. The main psychoactive compound of the Cannabis sativa plant is the phytocannabinoid delta-9-tetrahydrocannabinol (A-9 THC), and its status as a teratogen is controversial. THC and its endogenous analogues, anandamide (AEA) and 2-AG, exert their actions through specific receptors (eCBr) that activate intracellular signaling pathways. CB1r and CB2r, also called classic cannabinoid receptors, together with their endogenous ligands and the enzymes that synthesize and degrade them, constitute the endocannabinoid system. This system is distributed ubiquitously in various central and peripheral tissues. Although the endocannabinoid system's most studied role is controlling the release of neurotransmitters in the central nervous system, the study of long-term exposure to cannabinoids on fetal development is not well known and is vital for understanding environmental or pathological embryo-fetal or postnatal conditions. Prenatal exposure to cannabinoids in animal models has induced changes in placental and embryo-fetal organs. Particularly, cannabinoids could influence both neural and nonneural tissues and induce embryo-fetal pathological conditions in critical processes such as neural respiratory control. This review aims at the acute and chronic effects of prenatal exposure to cannabinoids on placental function and the embryo-fetal neurodevelopment of the respiratory pattern. The information provided here will serve as a theoretical framework to critically evaluate the teratogen effects of the consumption of cannabis during pregnancy.
Collapse
Affiliation(s)
- Daniela Cáceres
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Martín Ochoa
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Marcelo González-Ortiz
- Laboratorio de Investigación Materno-Fetal (LIMaF), Departamento de Obstetricia y Ginecología, Facultad de Medicina, Universidad de Concepción, Concepción, Chile
| | - Karina Bravo
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
- Facultad de Ingeniería, Universidad Autónoma de Chile, Providencia, Chile
| | - Jaime Eugenín
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.
| |
Collapse
|
26
|
Dai L, Wang X, Xiao Y. Role of chemosensitivity: Possible pathophysiological mediator of obstructive sleep apnea and type 2 diabetes. Sleep Med 2023; 101:490-496. [PMID: 36527940 DOI: 10.1016/j.sleep.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Obstructive sleep apnea (OSA) and type 2 diabetes show some mutual promotion of disease development. Variation in chemosensitivity is a key contributor to the pathophysiological mechanisms causing OSA and type 2 diabetes. According to studies conducted thus far, people with OSA or type 2 diabetes may have higher chemoreflex levels, but it is challenging to identify the precise changes because of variations in participant characteristics, the severity of the disease at the time of recruitment, and the small sample sizes in each study. Lowering chemosensitivity may also be viewed as a new issue for individuals with OSA and type 2 diabetes who require personalized care. The purpose of this review was to give an overview of chemosensitivity changes in OSA and glucose metabolism, as well as prospective therapeutic treatments for patients with OSA and type 2 diabetes.
Collapse
Affiliation(s)
- Lu Dai
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Xiaona Wang
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Yi Xiao
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.
| |
Collapse
|
27
|
Cates VC, Bruce CD, Marullo AL, Isakovich R, Saran G, Leacy JK, O′Halloran KD, Brutsaert TD, Sherpa MT, Day TA. Steady-state chemoreflex drive captures ventilatory acclimatization during incremental ascent to high altitude: Effect of acetazolamide. Physiol Rep 2022; 10:e15521. [PMID: 36461658 PMCID: PMC9718940 DOI: 10.14814/phy2.15521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023] Open
Abstract
Ventilatory acclimatization (VA) is important to maintain adequate oxygenation with ascent to high altitude (HA). Transient hypoxic ventilatory response tests lack feasibility and fail to capture the integrated steady-state responses to chronic hypoxic exposure in HA fieldwork. We recently characterized a novel index of steady-state respiratory chemoreflex drive (SSCD), accounting for integrated contributions from central and peripheral respiratory chemoreceptors during steady-state breathing at prevailing chemostimuli. Acetazolamide is often utilized during ascent for prevention or treatment of altitude-related illnesses, eliciting metabolic acidosis and stimulating respiratory chemoreceptors. To determine if SSCD reflects VA during ascent to HA, we characterized SSCD in 25 lowlanders during incremental ascent to 4240 m over 7 days. We subsequently compared two separate subgroups: no acetazolamide (NAz; n = 14) and those taking an oral prophylactic dose of acetazolamide (Az; 125 mg BID; n = 11). At 1130/1400 m (day zero) and 4240 m (day seven), steady-state measurements of resting ventilation (V̇I ; L/min), pressure of end-tidal (PET )CO2 (Torr), and peripheral oxygen saturation (SpO2 ; %) were measured. A stimulus index (SI; PET CO2 /SpO2 ) was calculated, and SSCD was calculated by indexing V̇I against SI. We found that (a) both V̇I and SSCD increased with ascent to 4240 m (day seven; V̇I : +39%, p < 0.0001, Hedges' g = 1.52; SSCD: +56.%, p < 0.0001, Hedges' g = 1.65), (b) and these responses were larger in the Az versus NAz subgroup (V̇I : p = 0.02, Hedges' g = 1.04; SSCD: p = 0.02, Hedges' g = 1.05). The SSCD metric may have utility in assessing VA during prolonged stays at altitude, providing a feasible alternative to transient chemoreflex tests.
Collapse
Affiliation(s)
- Valerie C. Cates
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Christina D. Bruce
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Anthony L. Marullo
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
- Department of Physiology. School of MedicineUniversity Cork CollegeCorkIreland
| | - Rodion Isakovich
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Gurkarn Saran
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Jack K. Leacy
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
- Department of Physiology. School of MedicineUniversity Cork CollegeCorkIreland
| | - Ken D. O′Halloran
- Department of Physiology. School of MedicineUniversity Cork CollegeCorkIreland
| | | | | | - Trevor A. Day
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| |
Collapse
|
28
|
Xia Y, Cui K, Alonso A, Lowenstein ED, Hernandez-Miranda LR. Transcription factors regulating the specification of brainstem respiratory neurons. Front Mol Neurosci 2022; 15:1072475. [PMID: 36523603 PMCID: PMC9745097 DOI: 10.3389/fnmol.2022.1072475] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/14/2022] [Indexed: 11/12/2023] Open
Abstract
Breathing (or respiration) is an unconscious and complex motor behavior which neuronal drive emerges from the brainstem. In simplistic terms, respiratory motor activity comprises two phases, inspiration (uptake of oxygen, O2) and expiration (release of carbon dioxide, CO2). Breathing is not rigid, but instead highly adaptable to external and internal physiological demands of the organism. The neurons that generate, monitor, and adjust breathing patterns locate to two major brainstem structures, the pons and medulla oblongata. Extensive research over the last three decades has begun to identify the developmental origins of most brainstem neurons that control different aspects of breathing. This research has also elucidated the transcriptional control that secures the specification of brainstem respiratory neurons. In this review, we aim to summarize our current knowledge on the transcriptional regulation that operates during the specification of respiratory neurons, and we will highlight the cell lineages that contribute to the central respiratory circuit. Lastly, we will discuss on genetic disturbances altering transcription factor regulation and their impact in hypoventilation disorders in humans.
Collapse
Affiliation(s)
- 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
| | - 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
| | - Antonia Alonso
- Functional Genoarchitecture and Neurobiology Groups, Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain
| | - Elijah D. Lowenstein
- Developmental Biology/Signal Transduction, Max Delbrück Center for Molecular Medicine, 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
| |
Collapse
|
29
|
Mendo B, Gonçalves M, Lopes L, Matos LC, Machado J. Can Yoga, Qigong, and Tai Chi Breathing Work Support the Psycho-Immune Homeostasis during and after the COVID-19 Pandemic? A Narrative Review. Healthcare (Basel) 2022; 10:healthcare10101934. [PMID: 36292380 PMCID: PMC9601556 DOI: 10.3390/healthcare10101934] [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: 08/08/2022] [Revised: 09/25/2022] [Accepted: 09/27/2022] [Indexed: 11/04/2022] Open
Abstract
Breathing is crucial in life; nevertheless, the healthcare community often overlooks the health potential of breathing techniques. Conscious manipulation of breathing to achieve specific health goals is found in yoga, Qigong and Tai Chi. This paper reviews the value of breathing exercises as a foremost mechanism for promoting, recuperating and maintaining health. Practices involving breathing techniques are described, and their prophylactic or therapeutic characteristics are explored. The main goals of this review are: (i) to summarize the evidence supporting the hypothesis that breathing practices have a significant beneficial impact on human health; (ii) to provide a deeper understanding of traditional biofeedback practices, particularly yoga, Qigong and Tai Chi, and outline their focus on breathing techniques; (iii) to outline specific immune-related responses, relevant for COVID-19 disorders; and (iv) to call for committed attention and action from the scientific community and health agencies in promoting the implementation of a practical and costless health program based on breathing techniques. This review shows the health potentials of breathing practices and exercises, which, by having a high benefit-cost ratio, could be selected and implemented as a primary standard routine in public health programs.
Collapse
Affiliation(s)
- Bruno Mendo
- ICBAS–Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313 Porto, Portugal
- CBSin–Center of BioSciences in Integrative Health, 4250-105 Porto, Portugal
- Correspondence:
| | - Mário Gonçalves
- ICBAS–Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313 Porto, Portugal
- CBSin–Center of BioSciences in Integrative Health, 4250-105 Porto, Portugal
| | - Lara Lopes
- ICBAS–Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313 Porto, Portugal
- CBSin–Center of BioSciences in Integrative Health, 4250-105 Porto, Portugal
| | - Luís Carlos Matos
- CBSin–Center of BioSciences in Integrative Health, 4250-105 Porto, Portugal
- Faculdade de Engenharia da Universidade do Porto, 4200-465 Porto, Portugal
- CTEC–Centro Transdisciplinar de Estudos da Consciência, Universidade Fernando Pessoa, 4249-004 Porto, Portugal
| | - Jorge Machado
- ICBAS–Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313 Porto, Portugal
- CBSin–Center of BioSciences in Integrative Health, 4250-105 Porto, Portugal
- LABIOMEP–Porto Biomechanics Laboratory, University of Porto, 4200-450 Porto, Portugal
| |
Collapse
|
30
|
Gourine AV, Dale N. Brain H + /CO 2 sensing and control by glial cells. Glia 2022; 70:1520-1535. [PMID: 35102601 DOI: 10.1002/glia.24152] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 01/04/2023]
Abstract
Maintenance of constant brain pH is critically important to support the activity of individual neurons, effective communication within the neuronal circuits, and, thus, efficient processing of information by the brain. This review article focuses on how glial cells detect and respond to changes in brain tissue pH and concentration of CO2 , and then trigger systemic and local adaptive mechanisms that ensure a stable milieu for the operation of brain circuits. We give a detailed account of the cellular and molecular mechanisms underlying sensitivity of glial cells to H+ and CO2 and discuss the role of glial chemosensitivity and signaling in operation of three key mechanisms that work in concert to keep the brain pH constant. We discuss evidence suggesting that astrocytes and marginal glial cells of the brainstem are critically important for central respiratory CO2 chemoreception-a fundamental physiological mechanism that regulates breathing in accord with changes in blood and brain pH and partial pressure of CO2 in order to maintain systemic pH homeostasis. We review evidence suggesting that astrocytes are also responsible for the maintenance of local brain tissue extracellular pH in conditions of variable acid loads associated with changes in the neuronal activity and metabolism, and discuss potential role of these glial cells in mediating the effects of CO2 on cerebral vasculature.
Collapse
Affiliation(s)
- Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, UK
| |
Collapse
|
31
|
Dean JB, Stavitzski NM. The O2-sensitive brain stem, hyperoxic hyperventilation, and CNS oxygen toxicity. Front Physiol 2022; 13:921470. [PMID: 35957982 PMCID: PMC9360621 DOI: 10.3389/fphys.2022.921470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Central nervous system oxygen toxicity (CNS-OT) is a complex disorder that presents, initially, as a sequence of cardio-respiratory abnormalities and nonconvulsive signs and symptoms (S/Sx) of brain stem origin that culminate in generalized seizures, loss of consciousness, and postictal cardiogenic pulmonary edema. The risk of CNS-OT and its antecedent “early toxic indications” are what limits the use of hyperbaric oxygen (HBO2) in hyperbaric and undersea medicine. The purpose of this review is to illustrate, based on animal research, how the temporal pattern of abnormal brain stem responses that precedes an “oxtox hit” provides researchers a window into the early neurological events underlying seizure genesis. Specifically, we focus on the phenomenon of hyperoxic hyperventilation, and the medullary neurons presumed to contribute in large part to this paradoxical respiratory response; neurons in the caudal Solitary complex (cSC) of the dorsomedial medulla, including putative CO2 chemoreceptor neurons. The electrophysiological and redox properties of O2-/CO2-sensitive cSC neurons identified in rat brain slice experiments are summarized. Additionally, evidence is summarized that supports the working hypothesis that seizure genesis originates in subcortical areas and involves cardio-respiratory centers and cranial nerve nuclei in the hind brain (brainstem and cerebellum) based on, respectively, the complex temporal pattern of abnormal cardio-respiratory responses and various nonconvulsive S/Sx that precede seizures during exposure to HBO2.
Collapse
|
32
|
da Silva Junior CA, Patrone LGA, Biancardi V, Vilela-Costa HH, Marques DA, Cristina-Silva C, da Costa Silva KS, Bícego KC, Szawka RE, Gargaglioni LH. Sexually dimorphic effects of prenatal diazepam exposure on respiratory control and the monoaminergic system of neonate and young rats. Pflugers Arch 2022; 474:1185-1200. [DOI: 10.1007/s00424-022-02730-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/05/2022] [Accepted: 07/08/2022] [Indexed: 11/30/2022]
|
33
|
Oliveira LM, Fernandes-Junior SA, Cabral LMC, Miranda NCS, Czeisler CM, Otero JJ, Moreira TS, Takakura AC. Regulation of blood vessels by ATP in the ventral medullary surface in a rat model of Parkinson's disease. Brain Res Bull 2022; 187:138-154. [PMID: 35777704 DOI: 10.1016/j.brainresbull.2022.06.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 05/26/2022] [Accepted: 06/25/2022] [Indexed: 11/17/2022]
Abstract
Parkinson's disease (PD) patients often experience impairment of autonomic and respiratory functions. These include conditions such as orthostatic hypotension and sleep apnea, which are highly correlated with dysfunctional central chemoreception. Blood flow is a fundamental determinant of tissue CO2/H+, yet the extent to which blood flow regulation within chemoreceptor regions contributes to respiratory behavior during neurological disease remains unknown. Here, we tested the hypothesis that 6-hydroxydopamine injection to inducing a known model of PD results in dysfunctional vascular homeostasis, biochemical dysregulation, and glial morphology of the ventral medullary surface (VMS). We show that hypercapnia (FiCO2 = 10%) induced elevated VMS pial vessel constriction in PD animals through a P2-receptor dependent mechanism. Similarly, we found a greater CO2-induced vascular constriction after ARL67156 (an ectonucleotidase inhibitor) in control and PD-induced animals. In addition, we also report that weighted gene correlational network analysis of the proteomic data showed a protein expression module differentially represented between both groups. This module showed that gene ontology enrichment for components of the ATP machinery were reduced in our PD-model compared to control animals. Altogether, our data indicate that dysfunction in purinergic signaling, potentially through altered ATP bioavailability in the VMS region, may compromise the RTN neuroglial vascular unit in a PD animal model.
Collapse
Affiliation(s)
- Luiz M Oliveira
- Departamento de Farmacologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP, 05508-000, Brazil
| | - Silvio A Fernandes-Junior
- Departamento de Farmacologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP, 05508-000, Brazil; The Ohio State University College of Medicine, Department of Pathology, USA
| | - Laís M C Cabral
- Departamento de Farmacologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP, 05508-000, Brazil
| | - Nicole C S Miranda
- Departamento de Farmacologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP, 05508-000, Brazil
| | | | - José J Otero
- The Ohio State University College of Medicine, Department of Pathology, USA
| | - Thiago S Moreira
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP, 05508-000, Brazil
| | - Ana C Takakura
- Departamento de Farmacologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, SP, 05508-000, Brazil.
| |
Collapse
|
34
|
Jareonsettasin P, Zeicu C, Diehl B, Harper RM, Astin R. Inappropriate Ventilatory Homeostatic Responses in Hospitalized COVID-19 Patients. Front Neurol 2022; 13:909915. [PMID: 35785338 PMCID: PMC9240262 DOI: 10.3389/fneur.2022.909915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/19/2022] [Indexed: 11/15/2022] Open
Abstract
Background The clinical presentation of COVID-19 suggests altered breathing control - tachypnoea, relative lack of dyspnoea, and often a discrepancy between severity of clinical and radiological findings. Few studies characterize and analyse the contribution of breathing drivers and their ventilatory and perceptual responses. Aim To establish the prevalence of inappropriate ventilatory and perceptual response in COVID-19, by characterizing the relationships between respiratory rate (RR), dyspnoea and arterial blood gas (ABG) in a cohort of COVID-19 patients at presentation to hospital, and their post-Covid respiratory sequelae at follow-up. Methods We conducted a retrospective cohort study including consecutive adult patients admitted to hospital with confirmed COVID-19 between 1st March 2020 and 30th April 2020. In those with concurrent ABG, RR and documented dyspnoea status on presentation, we documented patient characteristics, disease severity, and outcomes at hospital and 6-week post-discharge. Results Of 492 admissions, 194 patients met the inclusion criteria. Tachypnoea was present in 75% pronounced (RR>30) in 36%, and persisted during sleep. RR correlated with heart rate (HR) (r = 0.2674), temperature (r = 0.2824), CRP (r = 0.2561), Alveolar-arterial (A-a) gradient (r = 0.4189), and lower PaO2/FiO2 (PF) ratio (r = −0.3636). RR was not correlated with any neurological symptoms. Dyspnoea was correlated with RR (r = 0.2932), A-a gradient (r = 0.1723), and lower PF ratio (r = −0.1914), but not correlated with PaO2 (r = −0.1095), PaCO2 (r = −0.0598) or any recorded neurological symptom except for altered consciousness. Impaired ventilatory homeostatic control of pH/PaCO2 [tachypnoea (RR>20), hypocapnia (PaCO2 <4.6 kPa), and alkalosis (pH>7.45)] was observed in 29%. This group, of which 37% reported no dyspnoea, had more severe respiratory disease (A-a gradient 38.9 vs. 12.4 mmHg; PF ratio 120 vs. 238), and higher prevalence of anosmia (21 vs. 15%), dysgeusia (25 vs. 12%), headache (33 vs. 23%) and nausea (33 vs. 14%) with similar rates of new anxiety/depression (26 vs. 23%), but lower incidence of past neurological or psychiatric diagnoses (5 vs. 21%) compared to appropriate responders. Only 5% had hypoxia sufficiently severe to drive breathing (i.e. PaO2 <6.6 kPa). At 6 weeks post-discharge, 24% (8/34) showed a new breathing pattern disorder with no other neurological findings, nor previous respiratory, neurological, or psychiatric disorder diagnoses. Conclusions Impaired homeostatic control of ventilation i.e., tachypnoea, despite hypocapnia to the point of alkalosis appears prevalent in patients admitted to hospital with COVID-19, a finding typically accompanying more severe disease. Tachypnoea prevalence was between 12 and 29%. Data suggest that excessive tachypnoea is driven by both peripheral and central mechanisms, but not hypoxia. Over a third of patients with impaired homeostatic ventilatory control did not experience dyspnoea despite tachypnoea. A subset of followed-up patients developed post-covid breathing pattern disorder.
Collapse
Affiliation(s)
- Prem Jareonsettasin
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, United Kingdom
- Division of Medical Specialties, University College London Hospitals NHS Foundation Trust, London, United Kingdom
- *Correspondence: Prem Jareonsettasin
| | - Claudia Zeicu
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, United Kingdom
- Division of Medical Specialties, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Clinical Neurophysiology, University College London Hospitals NHS Foundation Trust National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Ronald M. Harper
- Department of Neurobiology and the Brain Research Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Rónan Astin
- Division of Medical Specialties, University College London Hospitals NHS Foundation Trust, London, United Kingdom
- NIHR University College London Hospitals Biomedical Research Centre, London, United Kingdom
| |
Collapse
|
35
|
Arce-Álvarez A, Salazar-Ardiles C, Cornejo C, Paez V, Vásquez-Muñoz M, Stillner-Vilches K, Jara CR, Ramirez-Campillo R, Izquierdo M, Andrade DC. Chemoreflex Control as the Cornerstone in Immersion Water Sports: Possible Role on Breath-Hold. Front Physiol 2022; 13:894921. [PMID: 35733994 PMCID: PMC9207453 DOI: 10.3389/fphys.2022.894921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 05/10/2022] [Indexed: 11/30/2022] Open
Abstract
Immersion water sports involve long-term apneas; therefore, athletes must physiologically adapt to maintain muscle oxygenation, despite not performing pulmonary ventilation. Breath-holding (i.e., apnea) is common in water sports, and it involves a decrease and increases PaO2 and PaCO2, respectively, as the primary signals that trigger the end of apnea. The principal physiological O2 sensors are the carotid bodies, which are able to detect arterial gases and metabolic alterations before reaching the brain, which aids in adjusting the cardiorespiratory system. Moreover, the principal H+/CO2 sensor is the retrotrapezoid nucleus, which is located at the brainstem level; this mechanism contributes to detecting respiratory and metabolic acidosis. Although these sensors have been characterized in pathophysiological states, current evidence shows a possible role for these mechanisms as physiological sensors during voluntary apnea. Divers and swimmer athletes have been found to displayed longer apnea times than land sports athletes, as well as decreased peripheral O2 and central CO2 chemoreflex control. However, although chemosensitivity at rest could be decreased, we recently found marked sympathoexcitation during maximum voluntary apnea in young swimmers, which could activate the spleen (which is a reservoir organ for oxygenated blood). Therefore, it is possible that the chemoreflex, autonomic function, and storage/delivery oxygen organ(s) are linked to apnea in immersion water sports. In this review, we summarized the available evidence related to chemoreflex control in immersion water sports. Subsequently, we propose a possible physiological mechanistic model that could contribute to providing new avenues for understanding the respiratory physiology of water sports.
Collapse
Affiliation(s)
- Alexis Arce-Álvarez
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
- Escuela de Kinesiología, Facultad de Salud, Universidad Católica Silva Henríquez, Santiago, Chile
- Navarrabiomed, Hospital Universitario de Navarra (CHN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Camila Salazar-Ardiles
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Carlos Cornejo
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Valeria Paez
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Manuel Vásquez-Muñoz
- Navarrabiomed, Hospital Universitario de Navarra (CHN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
- Clínica Santa María, Santiago, Chile
| | | | - Catherine R. Jara
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Rodrigo Ramirez-Campillo
- Exercise and Rehabilitation Sciences Laboratory, School of Physical Therapy, Faculty of Rehabilitation Sciences, Universidad Andres Bello, Santiago, Chile
| | - Mikel Izquierdo
- Navarrabiomed, Hospital Universitario de Navarra (CHN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - David C. Andrade
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
- *Correspondence: David C. Andrade, ,
| |
Collapse
|
36
|
Toledo C, Díaz-Jara E, Diaz HS, Schwarz KG, Pereyra KV, Las Heras A, Rios-Gallardo A, Andrade DC, Moreira T, Takakura A, Marcus NJ, Del Rio R. Medullary astrocytes mediate irregular breathing patterns generation in chronic heart failure through purinergic P2X7 receptor signalling. EBioMedicine 2022; 80:104044. [PMID: 35533501 PMCID: PMC9097632 DOI: 10.1016/j.ebiom.2022.104044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 11/05/2022] Open
Abstract
Background Breathing disorders (BD) (apnoeas/hypopneas, periodic breathing) are highly prevalent in chronic heart failure (CHF) and are associated with altered central respiratory control. Ample evidence identifies the retrotrapezoid nucleus (RTN) as an important chemosensitivity region for ventilatory control and generation of BD in CHF, however little is known about the cellular mechanisms underlying the RTN/BD relationship. Within the RTN, astrocyte‐mediated purinergic signalling modulates respiration, but the potential contribution of RTN astrocytes to BD in CHF has not been explored. Methods Selective neuron and/or astrocyte-targeted interventions using either optogenetic and chemogenetic manipulations in the RTN of CHF rats were used to unveil the contribution of the RTN on the development/maintenance of BD, the role played by astrocytes in BD and the molecular mechanism underpinning these alterations. Findings We showed that episodic photo-stimulation of RTN neurons triggered BD in healthy rats, and that RTN neurons ablation in CHF animals eliminates BD. Also, we found a reduction in astrocytes activity and ATP bioavailability within the RTN of CHF rats, and that chemogenetic restoration of normal RTN astrocyte activity and ATP levels improved breathing regularity in CHF. Importantly, P"X/ P2X7 receptor (P2X7r) expression was reduced in RTN astrocytes from CHF rats and viral vector-mediated delivery of human P2X7 P2X7r into astrocytes increases ATP bioavailability and abolished BD. Interpretation Our results support that RTN astrocytes play a pivotal role on BD generation and maintenance in the setting CHF by a mechanism encompassing P2X7r signalling. Funding This study was funded by the National Research and Development Agency of Chile (ANID).
Collapse
|
37
|
Ferretti G, Fagoni N, Taboni A, Vinetti G, di Prampero PE. A century of exercise physiology: key concepts on coupling respiratory oxygen flow to muscle energy demand during exercise. Eur J Appl Physiol 2022; 122:1317-1365. [PMID: 35217911 PMCID: PMC9132876 DOI: 10.1007/s00421-022-04901-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/25/2022] [Indexed: 12/26/2022]
Abstract
After a short historical account, and a discussion of Hill and Meyerhof's theory of the energetics of muscular exercise, we analyse steady-state rest and exercise as the condition wherein coupling of respiration to metabolism is most perfect. The quantitative relationships show that the homeostatic equilibrium, centred around arterial pH of 7.4 and arterial carbon dioxide partial pressure of 40 mmHg, is attained when the ratio of alveolar ventilation to carbon dioxide flow ([Formula: see text]) is - 21.6. Several combinations, exploited during exercise, of pertinent respiratory variables are compatible with this equilibrium, allowing adjustment of oxygen flow to oxygen demand without its alteration. During exercise transients, the balance is broken, but the coupling of respiration to metabolism is preserved when, as during moderate exercise, the respiratory system responds faster than the metabolic pathways. At higher exercise intensities, early blood lactate accumulation suggests that the coupling of respiration to metabolism is transiently broken, to be re-established when, at steady state, blood lactate stabilizes at higher levels than resting. In the severe exercise domain, coupling cannot be re-established, so that anaerobic lactic metabolism also contributes to sustain energy demand, lactate concentration goes up and arterial pH falls continuously. The [Formula: see text] decreases below - 21.6, because of ensuing hyperventilation, while lactate keeps being accumulated, so that exercise is rapidly interrupted. The most extreme rupture of the homeostatic equilibrium occurs during breath-holding, because oxygen flow from ambient air to mitochondria is interrupted. No coupling at all is possible between respiration and metabolism in this case.
Collapse
Affiliation(s)
- Guido Ferretti
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia, Brescia, Italy.
- Département d'Anesthésiologie, Pharmacologie et Soins Intensifs, Université de Genève, Genève, Switzerland.
| | - Nazzareno Fagoni
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia, Brescia, Italy
| | - Anna Taboni
- Département d'Anesthésiologie, Pharmacologie et Soins Intensifs, Université de Genève, Genève, Switzerland
| | - Giovanni Vinetti
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia, Brescia, Italy
| | | |
Collapse
|
38
|
Madirazza K, Pecotic R, Pavlinac Dodig I, Valic M, Dogas Z. Blockade of alpha2-adrenergic receptors in the caudal raphe region enhances the renal sympathetic nerve activity response to acute intermittent hypercapnia in rats. Physiol Res 2022; 71:159-169. [PMID: 35043650 DOI: 10.33549/physiolres.934717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The study investigated the role of alpha2-adrenergic receptors of the caudal raphe region in the sympathetic and cardiovascular responses to the acute intermittent hypercapnia (AIHc). Urethane-anesthetized, vagotomized, mechanically ventilated Sprague-Dawley rats (n=38) were exposed to the AIHc protocol (5×3 min, 15 % CO2+50 % O2) in hyperoxic background (50 % O2). alpha2-adrenergic receptor antagonist-yohimbine was applied intravenously (1 mg/kg, n=9) or microinjected into the caudal raphe region (2 mM, n=12) prior to exposure to AIHc. Control groups of animals received saline intravenously (n=7) or into the caudal raphe region (n=10) prior to exposure to AIHc. Renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and heart rate (HR) were monitored before exposure to the AIHc protocol (T0), during five hypercapnic episodes (THc1-5) and at 15 min following the end of the last hypercapnic episode (T15). Following intravenous administration of yohimbine, RSNA was significantly greater during THc1-5 and at T15 than in the control group (P<0.05). When yohimbine was microinjected into the caudal raphe region, AIHc elicited greater increases in RSNA during THc1-5 when compared to the controls (THc1: 138.0+/-4.0 % vs. 123.7+/-4.8 %, P=0.032; THc2: 137.1+/-5.0 % vs. 124.1+/-4.5 %, P=0.071; THc3: 143.1+/-6.4 % vs. 122.0±4.8 %, P=0.020; THc4: 146.1+/-6.2 % vs. 120.7+/-5.7 %, P=0.007 and THc5: 143.2+/-7.7 % vs. 119.2+/-7.2 %, P=0.038). During THc1-5, significant decreases in HR from T0 were observed in all groups, while changes in MAP were observed in the group that received yohimbine intravenously. These findings suggest that blockade of the alpha2-adrenegic receptors in the caudal raphe region might have an important role in sympathetic responses to AIHc.
Collapse
Affiliation(s)
- K Madirazza
- Department of Neuroscience, University of Split School of Medicine, Split, Croatia.
| | | | | | | | | |
Collapse
|
39
|
Feinstein JS, Gould D, Khalsa SS. Amygdala-driven apnea and the chemoreceptive origin of anxiety. Biol Psychol 2022; 170:108305. [PMID: 35271957 DOI: 10.1016/j.biopsycho.2022.108305] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 12/13/2022]
Abstract
Although the amygdala plays an important part in the pathogenesis of anxiety and generation of exteroceptive fear, recent discoveries have challenged the directionality of this brain-behavior relationship with respect to interoceptive fear. Here we highlight several paradoxical findings including: (1) amygdala lesion patients who experience excessive fear and panic following inhalation of carbon dioxide (CO2), (2) clinically anxious patients who have significantly smaller (rather than larger) amygdalae and a pronounced hypersensitivity toward CO2, and (3) epilepsy patients who exhibit apnea immediately following stimulation of their amygdala yet have no awareness that their breathing has stopped. The above findings elucidate an entirely novel role for the amygdala in the induction of apnea and inhibition of CO2-induced fear. Such a role is plausible given the strong inhibitory connections linking the central nucleus of the amygdala with respiratory and chemoreceptive centers in the brainstem. Based on this anatomical arrangement, we propose a model of Apnea-induced Anxiety (AiA) which predicts that recurring episodes of apnea are being unconsciously elicited by amygdala activation, resulting in transient spikes in CO2 that provoke fear and anxiety, and lead to characteristic patterns of escape and avoidance behavior in patients spanning the spectrum of anxiety. If this new conception of AiA proves to be true, and activation of the amygdala can repeatedly trigger states of apnea outside of one's awareness, then it remains possible that the chronicity of anxiety disorders is being interoceptively driven by a chemoreceptive system struggling to maintain homeostasis in the midst of these breathless states.
Collapse
Affiliation(s)
- Justin S Feinstein
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104; University of Iowa, Department of Neurology, Iowa City, Iowa, USA, 52242.
| | - Dylan Gould
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136
| | - Sahib S Khalsa
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104
| |
Collapse
|
40
|
Turk AZ, Bishop M, Adeck A, SheikhBahaei S. Astrocytic modulation of central pattern generating motor circuits. Glia 2022; 70:1506-1519. [PMID: 35212422 DOI: 10.1002/glia.24162] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 12/26/2022]
Abstract
Central pattern generators (CPGs) generate the rhythmic and coordinated neural features necessary for the proper conduction of complex behaviors. In particular, CPGs are crucial for complex motor behaviors such as locomotion, mastication, respiration, and vocal production. While the importance of these networks in modulating behavior is evident, the mechanisms driving these CPGs are still not fully understood. On the other hand, accumulating evidence suggests that astrocytes have a significant role in regulating the function of some of these CPGs. Here, we review the location, function, and role of astrocytes in locomotion, respiration, and mastication CPGs and propose that, similarly, astrocytes may also play a significant role in the vocalization CPG.
Collapse
Affiliation(s)
- Ariana Z Turk
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Mitchell Bishop
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Afuh Adeck
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Shahriar SheikhBahaei
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, Maryland, USA
| |
Collapse
|
41
|
Disordered breathing in severe cerebral illness - towards a conceptual framework. Respir Physiol Neurobiol 2022; 300:103869. [PMID: 35181538 DOI: 10.1016/j.resp.2022.103869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/26/2022] [Accepted: 02/11/2022] [Indexed: 12/16/2022]
Abstract
Despite potentially life-threatening symptoms of disordered breathing in severe cerebral illness, there are no clear recommendations on diagnostic and therapeutic strategies for these patients. To identify types of breathing disorders observed in severely neurological comprised patients, to direct further research on classification, pathophysiology, diagnosis and treatment for disordered breathing in cerebral disease. Data including polygraphy, transcutaneous capnometry, blood gas analysis and radiological examinations of patients with severe cerebral illness and disordered breathing admitted to the neurological intensive care were analyzed. Patients (15) presented with acquired central hypoventilation syndrome (ACHS), central bradypnea, central tachypnea, obstructive, mixed and central apneas and hypopneas, Cheyne Stokes respiration, ataxic (Biot's) breathing, cluster breathing and respiration alternans. Severe cerebral illness may result in an ACHS and in a variety of disorders of the respiratory rhythm. Two of these, abrupt switches between breathing patterns and respiration alternans, suggest the existence of a rhythmogenic respiratory network. Polygraphy, transcutaneous capnometry, blood gas analysis and MRI are promising tools for diagnosis and research alike.
Collapse
|
42
|
Semyanov A, Verkhratsky A. Inclusive Brain: From Neuronal Doctrine to the Active Milieu. FUNCTION (OXFORD, ENGLAND) 2022; 3:zqab069. [PMID: 35399497 PMCID: PMC8991029 DOI: 10.1093/function/zqab069] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 01/07/2023]
|
43
|
Kim KJ, Rivas E, Prejean B, Frisco D, Young M, Downs M. Novel Computerized Method for Automated Determination of Ventilatory Threshold and Respiratory Compensation Point. Front Physiol 2022; 12:782167. [PMID: 34975535 PMCID: PMC8718913 DOI: 10.3389/fphys.2021.782167] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/18/2021] [Indexed: 11/29/2022] Open
Abstract
Introduction: The ventilatory threshold (named as VT1) and the respiratory compensation point (named as VT2) describe prominent changes of metabolic demand and exercise intensity domains during an incremental exercise test. Methods: A novel computerized method based on the optimization method was developed for automatically determining VT1 and VT2 from expired air during a progressive maximal exercise test. A total of 109 peak cycle tests were performed by members of the US astronaut corps (74 males and 35 females). We compared the automatically determined VT1 and VT2 values against the visual subjective and independent analyses of three trained evaluators. We also characterized VT1 and VT2 and the respective absolute and relative work rates and distinguished differences between sexes. Results: The automated compared to the visual subjective values were analyzed for differences with t test, for agreement with Bland–Altman plots, and for equivalence with a two one-sided test approach. The results showed that the automated and visual subjective methods were statistically equivalent, and the proposed approach reliably determined VT1 and VT2 values. Females had lower absolute O2 uptake, work rate, and ventilation, and relative O2 uptake at VT1 and VT2 compared to men (p ≤ 0.04). VT1 and VT2 occurred at a greater relative percentage of their peak VO2 for females (67 and 88%) compared to males (55 and 74%; main effect for sex: p < 0.001). Overall, VT1 occurred at 58% of peak VO2, and VT2 occurred at 79% of peak VO2 (p < 0.0001). Conclusion: Improvements in determining of VT1 and VT2 by automated analysis are time efficient, valid, and comparable to subjective visual analysis and may provide valuable information in research and clinical practice as well as identifying exercise intensity domains of crewmembers in space.
Collapse
Affiliation(s)
| | | | | | | | | | - Meghan Downs
- NASA Johnson Space Center, Houston, TX, United States
| |
Collapse
|
44
|
Abstract
Breathing (or respiration) is a complex motor behavior that originates in the brainstem. In minimalistic terms, breathing can be divided into two phases: inspiration (uptake of oxygen, O2) and expiration (release of carbon dioxide, CO2). The neurons that discharge in synchrony with these phases are arranged in three major groups along the brainstem: (i) pontine, (ii) dorsal medullary, and (iii) ventral medullary. These groups are formed by diverse neuron types that coalesce into heterogeneous nuclei or complexes, among which the preBötzinger complex in the ventral medullary group contains cells that generate the respiratory rhythm (Chapter 1). The respiratory rhythm is not rigid, but instead highly adaptable to the physic demands of the organism. In order to generate the appropriate respiratory rhythm, the preBötzinger complex receives direct and indirect chemosensory information from other brainstem respiratory nuclei (Chapter 2) and peripheral organs (Chapter 3). Even though breathing is a hard-wired unconscious behavior, it can be temporarily altered at will by other higher-order brain structures (Chapter 6), and by emotional states (Chapter 7). In this chapter, we focus on the development of brainstem respiratory groups and highlight the cell lineages that contribute to central and peripheral chemoreflexes.
Collapse
Affiliation(s)
- Eser Göksu Isik
- Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Luis R Hernandez-Miranda
- Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
| |
Collapse
|
45
|
Langer T, Zadek F, Carbonara M, Caccioppola A, Brusatori S, Zoerle T, Bottazzini F, Ferraris Fusarini C, di Modugno A, Zanella A, Zanier ER, Fumagalli R, Pesenti A, Stocchetti N. Cerebrospinal Fluid and Arterial Acid-Base Equilibrium of Spontaneously Breathing Patients with Aneurismal Subarachnoid Hemorrhage. Neurocrit Care 2022; 37:102-110. [PMID: 35199305 PMCID: PMC9283163 DOI: 10.1007/s12028-022-01450-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 01/12/2022] [Indexed: 12/29/2022]
Abstract
BACKGROUND Hyperventilation resulting in hypocapnic alkalosis (HA) is frequently encountered in spontaneously breathing patients with acute cerebrovascular conditions. The underlying mechanisms of this respiratory response have not been fully elucidated. The present study describes, applying the physical-chemical approach, the acid-base characteristics of cerebrospinal fluid (CSF) and arterial plasma of spontaneously breathing patients with aneurismal subarachnoid hemorrhage (SAH) and compares these results with those of control patients. Moreover, it investigates the pathophysiologic mechanisms leading to HA in SAH. METHODS Patients with SAH admitted to the neurological intensive care unit and patients (American Society of Anesthesiologists physical status of 1 and 2) undergoing elective surgery under spinal anesthesia were enrolled. CSF and arterial samples were collected simultaneously. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide (PCO2), weak noncarbonic acids (ATOT), and pH were measured in CSF and arterial blood samples. RESULTS Twenty spontaneously breathing patients with SAH and 25 controls were enrolled. The CSF of patients with SAH, as compared with controls, was characterized by a lower SID (23.1 ± 2.3 vs. 26.5 ± 1.4 mmol/L, p < 0.001) and PCO2 (40 ± 4 vs. 46 ± 3 mm Hg, p < 0.001), whereas no differences in ATOT (1.2 ± 0.5 vs. 1.2 ± 0.2 mmol/L, p = 0.95) and pH (7.34 ± 0.06 vs. 7.35 ± 0.02, p = 0.69) were observed. The reduced CSF SID was mainly caused by a higher lactate concentration (3.3 ± 1.3 vs. 1.4 ± 0.2 mmol/L, p < 0.001). A linear association (r = 0.71, p < 0.001) was found between CSF SID and arterial PCO2. A higher proportion of patients with SAH were characterized by arterial HA, as compared with controls (40 vs. 4%, p = 0.003). A reduced CSF-to-plasma difference in PCO2 was observed in nonhyperventilating patients with SAH (0.4 ± 3.8 vs. 7.8 ± 3.7 mm Hg, p < 0.001). CONCLUSIONS Patients with SAH have a reduction of CSF SID due to an increased lactate concentration. The resulting localized acidifying effect is compensated by CSF hypocapnia, yielding normal CSF pH values and resulting in a higher incidence of arterial HA.
Collapse
Affiliation(s)
- Thomas Langer
- Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy.
- Department of Anesthesia and Intensive Care Medicine, Niguarda Ca' Granda, Milan, Italy.
| | - Francesco Zadek
- Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Marco Carbonara
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessio Caccioppola
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Serena Brusatori
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Tommaso Zoerle
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Francesco Bottazzini
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Adriana di Modugno
- Central Laboratory, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alberto Zanella
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Elisa R Zanier
- Laboratory of Acute Brain Injury and Therapeutic Strategies, Department of Neuroscience, Istituto Di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Roberto Fumagalli
- Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy
- Department of Anesthesia and Intensive Care Medicine, Niguarda Ca' Granda, Milan, Italy
| | - Antonio Pesenti
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Nino Stocchetti
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| |
Collapse
|
46
|
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.
Collapse
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
| |
Collapse
|
47
|
LoMauro A, Aliverti A. Sex and gender in respiratory physiology. Eur Respir Rev 2021; 30:30/162/210038. [PMID: 34750114 DOI: 10.1183/16000617.0038-2021] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/08/2021] [Indexed: 11/05/2022] Open
Abstract
Sex is a biological concept determined at conception. Gender is a social concept. Medicine recognises sex as a biological variable and recommends including sex as a factor in clinical practice norms and as a topic of bench and clinical research. Sex plays a role in respiratory physiology according to two pathways: hormones and anatomy, with females characterised by smaller dimensions at every level of the respiratory system. Sex hormones also play specific roles in lung inflammatory processes, breathing control and in response to diseases. The literature is extremely controversial because many factors need to be considered to avoid erroneous comparisons. The main difficulty lies in creating homogeneous groups of subjects according to age, body weight, lung/airway size, fluctuations in circulating hormone levels, and exercise protocol. Because almost all of the knowledge available in physiology is based on research in males, medicine for women is therefore less evidence-based than that being applied to men. Finally, the number of transsexual people is increasing and they represent new challenges for clinicians, due to the anatomical and physiological changes that they undergo.
Collapse
Affiliation(s)
- Antonella LoMauro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| |
Collapse
|
48
|
Guyenet PG, Stornetta RL. Rostral ventrolateral medulla, retropontine region and autonomic regulations. Auton Neurosci 2021; 237:102922. [PMID: 34814098 DOI: 10.1016/j.autneu.2021.102922] [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: 03/25/2021] [Revised: 11/08/2021] [Accepted: 11/15/2021] [Indexed: 12/17/2022]
Abstract
The rostral half of the ventrolateral medulla (RVLM) and adjacent ventrolateral retropontine region (henceforth RVLMRP) have been divided into various sectors by neuroscientists interested in breathing or autonomic regulations. The RVLMRP regulates respiration, glycemia, vigilance and inflammation, in addition to blood pressure. It contains interoceptors that respond to acidification, hypoxia and intracranial pressure and its rostral end contains the retrotrapezoid nucleus (RTN) which is the main central respiratory chemoreceptor. Acid detection by the RTN is an intrinsic property of the principal neurons that is enhanced by paracrine influences from surrounding astrocytes and CO2-dependent vascular constriction. RTN mediates the hypercapnic ventilatory response via complex projections to the respiratory pattern generator (CPG). The RVLM contributes to autonomic response patterns via differential recruitment of several subtypes of adrenergic (C1) and non-adrenergic neurons that directly innervate sympathetic and parasympathetic preganglionic neurons. The RVLM also innervates many brainstem and hypothalamic nuclei that contribute, albeit less directly, to autonomic responses. All lower brainstem noradrenergic clusters including the locus coeruleus are among these targets. Sympathetic tone to the circulatory system is regulated by subsets of presympathetic RVLM neurons whose activity is continuously restrained by the baroreceptors and modulated by the respiratory CPG. The inhibitory input from baroreceptors and the excitatory input from the respiratory CPG originate from neurons located in or close to the rhythm generating region of the respiratory CPG (preBötzinger complex).
Collapse
Affiliation(s)
- Patrice G Guyenet
- University of Virginia School of Medicine, Department of Pharmacology, 1340 Jefferson Park Avenue, Charlottesville, VA 22908-0735, USA.
| | - Ruth L Stornetta
- University of Virginia School of Medicine, Department of Pharmacology, 1340 Jefferson Park Avenue, Charlottesville, VA 22908-0735, USA.
| |
Collapse
|
49
|
Randelman M, Zholudeva LV, Vinit S, Lane MA. Respiratory Training and Plasticity After Cervical Spinal Cord Injury. Front Cell Neurosci 2021; 15:700821. [PMID: 34621156 PMCID: PMC8490715 DOI: 10.3389/fncel.2021.700821] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/11/2021] [Indexed: 12/30/2022] Open
Abstract
While spinal cord injuries (SCIs) result in a vast array of functional deficits, many of which are life threatening, the majority of SCIs are anatomically incomplete. Spared neural pathways contribute to functional and anatomical neuroplasticity that can occur spontaneously, or can be harnessed using rehabilitative, electrophysiological, or pharmacological strategies. With a focus on respiratory networks that are affected by cervical level SCI, the present review summarizes how non-invasive respiratory treatments can be used to harness this neuroplastic potential and enhance long-term recovery. Specific attention is given to "respiratory training" strategies currently used clinically (e.g., strength training) and those being developed through pre-clinical and early clinical testing [e.g., intermittent chemical stimulation via altering inhaled oxygen (hypoxia) or carbon dioxide stimulation]. Consideration is also given to the effect of training on non-respiratory (e.g., locomotor) networks. This review highlights advances in this area of pre-clinical and translational research, with insight into future directions for enhancing plasticity and improving functional outcomes after SCI.
Collapse
Affiliation(s)
- Margo Randelman
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Lyandysha V Zholudeva
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States.,Gladstone Institutes, San Francisco, CA, United States
| | - Stéphane Vinit
- INSERM, END-ICAP, Université Paris-Saclay, UVSQ, Versailles, France
| | - Michael A Lane
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States.,Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, United States
| |
Collapse
|
50
|
Hatano K, Matsuura R, Ohtsuka Y, Yunoki T. Enhancement of self-sustained muscle activity through external dead space ventilation appears to be associated with hypercapnia. Respir Physiol Neurobiol 2021; 295:103777. [PMID: 34425262 DOI: 10.1016/j.resp.2021.103777] [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: 04/01/2021] [Revised: 07/24/2021] [Accepted: 08/19/2021] [Indexed: 11/19/2022]
Abstract
We reported that external dead space ventilation (EDSV) enhanced self-sustained muscle activity (SSMA) of the human soleus muscle, which is an indirect observation of plateau potentials. However, the main factor for EDSV to enhance SSMA remains unclear. The purpose of the present study was to examine the effects of EDSV-induced hypercapnia, hypoxia, and hyperventilation on SSMA. In Experiment 1 (n = 11; normal breathing [NB], EDSV, hypoxia, and voluntary hyperventilation conditions) and Experiment 2 (n = 9; NB and normoxic hypercapnia [NH] conditions), SSMA was evoked by electrical train stimulations of the right tibial nerve and measured using surface electromyography under each respiratory condition. In Experiment 1, SSMA was significantly higher than that in the NB condition only in the EDSV condition (P < 0.05). In Experiment 2, SSMA was higher in the NH condition than in the NB condition (P < 0.05). These results suggest that the EDSV-enhanced SSMA is due to hypercapnia, not hypoxia or increased ventilation.
Collapse
Affiliation(s)
- Kei Hatano
- Graduate School of Education, Hokkaido University, Sapporo, Japan.
| | - Ryouta Matsuura
- Graduate School of Education, Joetsu University of Education, Japan
| | - Yoshinori Ohtsuka
- Department of Sports and Human Studies, Sapporo International University, Japan
| | | |
Collapse
|