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Nuding SC, Segers LS, Iceman K, O'Connor R, Dean JB, Valarezo PA, Shuman D, Solomon IC, Bolser DC, Morris KF, Lindsey BG. Hypoxia evokes a sequence of raphe-pontomedullary network operations for inspiratory drive amplification and gasping. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.07.566027. [PMID: 37986850 PMCID: PMC10659307 DOI: 10.1101/2023.11.07.566027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Hypoxia can trigger a sequence of breathing-related behaviors, from tachypnea to apneusis to apnea and gasping, an autoresuscitative behavior that, via large tidal volumes and altered intrathoracic pressure, can enhance coronary perfusion, carotid blood flow, and sympathetic activity, and thereby coordinate cardiac and respiratory functions. We tested the hypothesis that hypoxia-evoked gasps are amplified through a disinhibitory microcircuit within the inspiratory neuron chain and a distributed efference copy mechanism that generates coordinated gasp-like discharges concurrently in other circuits of the raphe-pontomedullary respiratory network. Data were obtained from 6 decerebrate, vagotomized, neuromuscularly-blocked, and artificially ventilated adult cats. Arterial blood pressure, phrenic nerve activity, end-tidal CO2, and other parameters were monitored. Hypoxia was produced by ventilation with a gas mixture of 5% O2 in nitrogen (N2). Neuron spike trains were recorded at multiple pontomedullary sites simultaneously and evaluated for firing rate modulations and short-time scale correlations indicative of functional connectivity. Experimental perturbations evoked reconfiguration of raphe-pontomedullary circuits during tachypnea, apneusis and augmented bursts, apnea, and gasping. The functional connectivity, altered firing rates, efference copy of gasp drive, and coordinated step increments in blood pressure reported here support a distributed brain stem network model for amplification and broadcasting of inspiratory drive during autoresuscitative gasping that begins with a reduction in inhibition by expiratory neurons and an initial loss of inspiratory drive during hypoxic apnea.
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2
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Koucký V, Koucká P, Koucký M. Hyperoxic ventilatory response in infants is related to nocturnal hypoxaemia. ERJ Open Res 2024; 10:00512-2023. [PMID: 38333650 PMCID: PMC10851931 DOI: 10.1183/23120541.00512-2023] [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: 07/19/2023] [Accepted: 10/22/2023] [Indexed: 02/10/2024] Open
Abstract
Background The carotid bodies primarily serve as oxaemia sensors that affect tidal breathing. Their function has not yet been studied in infants with nocturnal hypoxaemia. This cross-sectional study aimed to characterise the hyperoxic ventilatory response (HVR) in infants and its relationship to nocturnal hypoxaemia. Methods The HVR was analysed in term infants aged <24 months with childhood interstitial lung disease (chILD), those with severe recurrent wheezing (wheeze), and nonrespiratory controls. The HVR timing was characterised using hyperoxia response time (HRT1), and HVR magnitude was characterised by the relative change in minute volume between normoxia and 30-s hyperoxia (VE_dH30). Time spent with an arterial haemoglobin oxygen saturation (SpO2) <90% during overnight monitoring (t90) was estimated. Results HVR data were available for 23 infants with chILD, 24 wheeze and 14 control infants. A significant decrease in minute volume under 30 s of hyperoxia was observed in all patients. HRT1 was shorter in chILD (5.6±1.2 s) and wheeze (5.9±1.5 s) groups than in the controls (12.6±5.5 s) (ANOVA p<0.001). VE_dH30 was increased in the chILD group (24.3±8.0%) compared with that in the controls (14.7±9.2%) (p=0.003). t90 was abnormal in the wheeze (8.0±5.0%) and chILD (32.7±25.8%) groups and higher in the chILD group than in the controls (p<0.001). HRT1 negatively correlated with t90 in all groups. Conclusion Significant differences in HVR timing and magnitude were noted in the chILD, wheeze and control groups. A relationship between nocturnal hypoxaemia and HRT1 was proposed. HVR characterisation may help identify patients with abnormal nocturnal SpO2.
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Affiliation(s)
- Václav Koucký
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - Pavlína Koucká
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - Miroslav Koucký
- Department of Mathematics, Faculty of Science, Humanities and Education, Technical University of Liberec, Liberec, Czech Republic
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Iturriaga R. Carotid body contribution to the physio-pathological consequences of intermittent hypoxia: role of nitro-oxidative stress and inflammation. J Physiol 2023; 601:5495-5507. [PMID: 37119020 DOI: 10.1113/jp284112] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/24/2023] [Indexed: 04/30/2023] Open
Abstract
Obstructive sleep apnoea (OSA), characterized by chronic intermittent hypoxia (CIH), is considered to be an independent risk for hypertension. The pathological cardiorespiratory consequences of OSA have been attributed to systemic oxidative stress, inflammation and sympathetic overflow induced by CIH, but an emerging body of evidence indicates that a nitro-oxidative and pro-inflammatory milieu within the carotid body (CB) is involved in the potentiation of CB chemosensory responses to hypoxia, which contribute to enhance the sympathetic activity. Accordingly, autonomic and cardiovascular alterations induced by CIH are critically dependent on an abnormally heightened CB chemosensory input to the nucleus of tractus solitarius (NTS), where second-order neurons project onto the rostral ventrolateral medulla (RVLM), activating pre-sympathetic neurons that control pre-ganglionic sympathetic neurons. CIH produces oxidative stress and neuroinflammation in the NTS and RVLM, which may contribute to the long-term irreversibility of the CIH-induced alterations. This brief review is mainly focused on the contribution of nitro-oxidative stress and pro-inflammatory molecules on the hyperactivation of the hypoxic chemoreflex pathway including the CB and the brainstem centres, and whether the persistence of autonomic and cardiorespiratory alterations may depend on the glial-related neuroinflammation induced by the enhanced CB chemosensory afferent input.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación en Fisiología y Medicina de Altura, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile
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4
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Moon RY, Carlin RF, Hand I. Evidence Base for 2022 Updated Recommendations for a Safe Infant Sleeping Environment to Reduce the Risk of Sleep-Related Infant Deaths. Pediatrics 2022; 150:188305. [PMID: 35921639 DOI: 10.1542/peds.2022-057991] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Every year in the United States, approximately 3500 infants die of sleep-related infant deaths, including sudden infant death syndrome (SIDS) (International Statistical Classification of Diseases and Related Health Problems 10th Revision [ICD-10] R95), ill-defined deaths (ICD-10 R99), and accidental suffocation and strangulation in bed (ICD-10 W75). After a substantial decline in sleep-related deaths in the 1990s, the overall death rate attributable to sleep-related infant deaths have remained stagnant since 2000, and disparities persist. The triple risk model proposes that SIDS occurs when an infant with intrinsic vulnerability (often manifested by impaired arousal, cardiorespiratory, and/or autonomic responses) undergoes an exogenous trigger event (eg, exposure to an unsafe sleeping environment) during a critical developmental period. The American Academy of Pediatrics recommends a safe sleep environment to reduce the risk of all sleep-related deaths. This includes supine positioning; use of a firm, noninclined sleep surface; room sharing without bed sharing; and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include human milk feeding; avoidance of exposure to nicotine, alcohol, marijuana, opioids, and illicit drugs; routine immunization; and use of a pacifier. New recommendations are presented regarding noninclined sleep surfaces, short-term emergency sleep locations, use of cardboard boxes as a sleep location, bed sharing, substance use, home cardiorespiratory monitors, and tummy time. In addition, additional information to assist parents, physicians, and nonphysician clinicians in assessing the risk of specific bed-sharing situations is included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, which is included in this issue.
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Affiliation(s)
- Rachel Y Moon
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Rebecca F Carlin
- Division of Pediatric Critical Care and Hospital Medicine, Department of Pediatrics, Columbia University Irving Medical Center, NewYork-Presbyterian Hospital, New York City, New York
| | - Ivan Hand
- Department of Pediatrics, SUNY-Downstate College of Medicine, NYC Health + Hospitals, Kings County, Brooklyn, New York
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Martin RJ, Mitchell LJ, MacFarlane PM. Apnea of prematurity and sudden infant death syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:43-52. [PMID: 36031315 DOI: 10.1016/b978-0-323-91532-8.00010-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Apnea is a frequent occurrence in prematurity and its prevalence in the most severely preterm population is indicative of an immature respiratory neural control system. Preterm infants are also at increased risk of Sudden Infant Death Syndrome (SIDS), which has been associated with similar respiratory neural control dysfunction seen in prematurity. Generally, abnormalities in both central and peripheral mechanisms of respiratory control are thought to be key underlying features of abnormal respiratory system development. Numerous factors contribute to the etiology of apnea and respiratory control dysfunction including the environment (e.g., substance use/misuse), sex, genetics, a vulnerable neonate, and various underlying comorbidities. However, there are major gaps in our understanding of both normal and abnormal respiratory control system development, which highlights the need for continued research using novel and innovative methods.
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Affiliation(s)
- Richard J Martin
- Division of Neonatology, Department of Pediatrics, Rainbow Babies & Children's Hospital, Case Western Reserve University, Cleveland, OH, United States.
| | - Lisa J Mitchell
- Division of Neonatology, Department of Pediatrics, Rainbow Babies & Children's Hospital, Case Western Reserve University, Cleveland, OH, United States
| | - Peter M MacFarlane
- Division of Neonatology, Department of Pediatrics, Rainbow Babies & Children's Hospital, Case Western Reserve University, Cleveland, OH, United States
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Neubauer J, Forst AL, Warth R, Both CP, Haas C, Thomas J. Genetic variants in eleven central and peripheral chemoreceptor genes in sudden infant death syndrome. Pediatr Res 2022; 92:1026-1033. [PMID: 35102300 PMCID: PMC9586864 DOI: 10.1038/s41390-021-01899-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 07/14/2021] [Accepted: 08/16/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Sudden infant death syndrome (SIDS) is still one of the leading causes of postnatal infant death in developed countries. The occurrence of SIDS is described by a multifactorial etiology that involves the respiratory control system including chemoreception. It is still unclear whether genetic variants in genes involved in respiratory chemoreception might play a role in SIDS. METHODS The exome data of 155 SIDS cases were screened for variants within 11 genes described in chemoreception. Pathogenicity of variants was assigned based on the assessment of variant types and in silico protein predictions according to the current recommendations of the American College of Medical Genetics and Genomics. RESULTS Potential pathogenic variants in genes encoding proteins involved in respiratory chemoreception could be identified in 5 (3%) SIDS cases. Two of the variants (R137S/A188S) were found in the KNCJ16 gene, which encodes for the potassium channel Kir5.1, presumably involved in central chemoreception. Electrophysiologic analysis of these KCNJ16 variants revealed a loss-of-function for the R137S variant but no obvious impairment for the A188S variant. CONCLUSIONS Genetic variants in genes involved in respiratory chemoreception may be a risk factor in a fraction of SIDS cases and may thereby contribute to the multifactorial etiology of SIDS. IMPACT What is the key message of your article? Gene variants encoding proteins involved in respiratory chemoreception may play a role in a minority of SIDS cases. What does it add to the existing literature? Although impaired respiratory chemoreception has been suggested as an important risk factor for SIDS, genetic variants in single genes seem to play a minor role. What is the impact? This study supports previous findings, which indicate that genetic variants in single genes involved in respiratory control do not have a dominant role in SIDS.
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Affiliation(s)
- Jacqueline Neubauer
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Anna-Lena Forst
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Christian Peter Both
- grid.412341.10000 0001 0726 4330Department of Anesthesiology, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Cordula Haas
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Jörg Thomas
- Department of Anesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.
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Iturriaga R, Alcayaga J, Chapleau MW, Somers VK. Carotid body chemoreceptors: physiology, pathology, and implications for health and disease. Physiol Rev 2021; 101:1177-1235. [PMID: 33570461 PMCID: PMC8526340 DOI: 10.1152/physrev.00039.2019] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The carotid body (CB) is the main peripheral chemoreceptor for arterial respiratory gases O2 and CO2 and pH, eliciting reflex ventilatory, cardiovascular, and humoral responses to maintain homeostasis. This review examines the fundamental biology underlying CB chemoreceptor function, its contribution to integrated physiological responses, and its role in maintaining health and potentiating disease. Emphasis is placed on 1) transduction mechanisms in chemoreceptor (type I) cells, highlighting the role played by the hypoxic inhibition of O2-dependent K+ channels and mitochondrial oxidative metabolism, and their modification by intracellular molecules and other ion channels; 2) synaptic mechanisms linking type I cells and petrosal nerve terminals, focusing on the role played by the main proposed transmitters and modulatory gases, and the participation of glial cells in regulation of the chemosensory process; 3) integrated reflex responses to CB activation, emphasizing that the responses differ dramatically depending on the nature of the physiological, pathological, or environmental challenges, and the interactions of the chemoreceptor reflex with other reflexes in optimizing oxygen delivery to the tissues; and 4) the contribution of enhanced CB chemosensory discharge to autonomic and cardiorespiratory pathophysiology in obstructive sleep apnea, congestive heart failure, resistant hypertension, and metabolic diseases and how modulation of enhanced CB reactivity in disease conditions may attenuate pathophysiology.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, and Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Julio Alcayaga
- Laboratorio de Fisiología Celular, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Mark W Chapleau
- Department of Internal Medicine, University of Iowa and Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Virend K Somers
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
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8
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Zhang M, Du S, Ou H, Cui R, Jiang N, Lin Y, Ge R, Ma D, Zhang J. Ablation of Zfhx4 results in early postnatal lethality by disrupting the respiratory center in mice. J Mol Cell Biol 2021; 13:210-224. [PMID: 33475140 PMCID: PMC8260053 DOI: 10.1093/jmcb/mjaa081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 11/19/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023] Open
Abstract
Breathing is an integrated motor behavior that is driven and controlled by a network of brainstem neurons. Zfhx4 is a zinc finger transcription factor and our results showed that it was specifically expressed in several regions of the mouse brainstem. Mice lacking Zfhx4 died shortly after birth from an apparent inability to initiate respiration. We also found that the electrical rhythm of brainstem‒spinal cord preparations was significantly depressed in Zfhx4-null mice compared to wild-type mice. Immunofluorescence staining revealed that Zfhx4 was coexpressed with Phox2b and Math1 in the brainstem and that Zfhx4 ablation greatly decreased the expression of these proteins, especially in the retrotrapezoid nucleus. Combined ChIP‒seq and mRNA expression microarray analysis identified Phox2b as the direct downstream target gene of Zfhx4, and this finding was validated by ChIP‒qPCR. Previous studies have reported that both Phox2b and Math1 play key roles in the development of the respiratory center, and Phox2b and Math1 knockout mice are neonatal lethal due to severe central apnea. On top of this, our study revealed that Zfhx4 is a critical regulator of Phox2b expression and essential for perinatal breathing.
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Affiliation(s)
- Meiqin Zhang
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Sichen Du
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Huayuan Ou
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Renjie Cui
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Nan Jiang
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yifeng Lin
- Children's Hospital, Fudan University, Shanghai 201102, China
| | - Runsheng Ge
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Duan Ma
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Children's Hospital, Fudan University, Shanghai 201102, China
| | - Jin Zhang
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences & Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
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Bednarczuk N, Milner A, Greenough A. The Role of Maternal Smoking in Sudden Fetal and Infant Death Pathogenesis. Front Neurol 2020; 11:586068. [PMID: 33193050 PMCID: PMC7644853 DOI: 10.3389/fneur.2020.586068] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/14/2020] [Indexed: 12/18/2022] Open
Abstract
Maternal smoking is a risk factor for both sudden infant death syndrome (SIDS) and sudden intrauterine unexplained death syndrome (SIUDS). Both SIDS and SIUDS are more frequently observed in infants of smoking mothers. The global prevalence of smoking during pregnancy is 1.7% and up to 8.1% of women in Europe smoke during pregnancy and worldwide 250 million women smoke during pregnancy. Infants born to mothers who smoke have an abnormal response to hypoxia and hypercarbia and they also have reduced arousal responses. The harmful effects of tobacco smoke are mainly mediated by release of carbon monoxide and nicotine. Nicotine can enter the fetal circulation and affect multiple developing organs including the lungs, adrenal glands and the brain. Abnormalities in brainstem nuclei crucial to respiratory control, the cerebral cortex and the autonomic nervous system have been demonstrated. In addition, hypodevelopment of the intermediolateral nucleus in the spinal cord has been reported. It initiates episodic respiratory movements that facilitate lung development. Furthermore, abnormal maturation and transmitter levels in the carotid bodies have been described which would make infants more vulnerable to hypoxic challenges. Unfortunately, smoking cessation programs do not appear to have significantly reduced the number of pregnant women who smoke.
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Affiliation(s)
- Nadja Bednarczuk
- Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom
| | - Anthony Milner
- Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom
| | - Anne Greenough
- Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom.,The Asthma UK Centre for Allergic Mechanisms of Asthma, King's College London, London, United Kingdom.,National Institute for Health Research (NIHR) Biomedical Research Centre at Guy's & St Thomas' National Health Service (NHS) Foundation Trust and King's College London, London, United Kingdom
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10
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Patrone LGA, Capalbo AC, Marques DA, Bícego KC, Gargaglioni LH. An age- and sex-dependent role of catecholaminergic neurons in the control of breathing and hypoxic chemoreflex during postnatal development. Brain Res 2019; 1726:146508. [PMID: 31606412 DOI: 10.1016/j.brainres.2019.146508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/23/2019] [Accepted: 10/09/2019] [Indexed: 12/27/2022]
Abstract
The respiratory system undergoes significant development during the postnatal phase. Maturation of brainstem catecholaminergic (CA) neurons is important for the control and modulation of respiratory rhythmogenesis, as well as for chemoreception in early life. We demonstrated an inhibitory role for CA neurons in CO2 chemosensitivity in neonatal and juvenile male and female rats, but information regarding their role in the hypoxic ventilatory response (HVR) is lacking. We evaluated the contribution of brainstem CA neurons in the HVR during postnatal (P) development (P7-8, P14-15 and P20-21) in male and female rats through chemical injury with conjugated saporin anti-dopamine beta-hydroxylase (DβH-SAP, 420 ng·μL-1) injected in the fourth ventricle. Ventilation (V̇E) and oxygen consumption were recorded one week after the lesion in unanesthetized rats during exposure to normoxia and hypoxia. Hypoxia reduced breathing variability in P7-8 control rats of both sexes. At P7-8, the HVR for lesioned males and females increased 27% and 24%, respectively. Additionally, the lesion reduced the normoxic breathing variability in both sexes at P7-8, but hypoxia partially reverted this effect. For P14-15, the increase in V̇E during hypoxia was 30% higher for male and 24% higher for female lesioned animals. A sex-specific difference was detected at P20-21, as lesioned males exhibited a 24% decrease in the HVR, while lesioned females experienced a 22% increase. Furthermore, the hypoxia-induced body temperature reduction was attenuated in P20-21 lesioned females. We conclude that brainstem CA neurons modulate the HRV during the postnatal phase, and possibly thermoregulation during hypoxia.
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Affiliation(s)
- Luis Gustavo A Patrone
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Aretuza C Capalbo
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Danuzia A Marques
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV, Jaboticabal, SP, Brazil.
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11
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Garcia AJ, Viemari JC, Khuu MA. Respiratory rhythm generation, hypoxia, and oxidative stress-Implications for development. Respir Physiol Neurobiol 2019; 270:103259. [PMID: 31369874 DOI: 10.1016/j.resp.2019.103259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/15/2019] [Accepted: 07/24/2019] [Indexed: 02/07/2023]
Abstract
Encountered in a number of clinical conditions, repeated hypoxia/reoxygenation during the neonatal period can pose both a threat to immediate survival as well as a diminished quality of living later in life. This review focuses on our current understanding of central respiratory rhythm generation and the role that hypoxia and reoxygenation play in influencing rhythmogenesis. Here, we examine the stereotypical response of the inspiratory rhythm from the preBötzinger complex (preBötC), basic neuronal mechanisms that support rhythm generation during the peri-hypoxic interval, and the physiological consequences of inspiratory network responsivity to hypoxia and reoxygenation, acute and chronic intermittent hypoxia, and oxidative stress. These topics are examined in the context of Sudden Infant Death Syndrome, apneas of prematurity, and neonatal abstinence syndrome.
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Affiliation(s)
- Alfredo J Garcia
- Institute for Integrative Physiology, Section of Emergency Medicine, The University of Chicago, Chicago, 60637, IL, United States
| | - Jean Charles Viemari
- Institut de Neurosciences de la Timone, P3M team, UMR7289 CNRS & AMU, Faculté de Médecine de la Timone, 27 Bd Jean Moulin, Marseille, 13005, France
| | - Maggie A Khuu
- Institute for Integrative Physiology, Section of Emergency Medicine, The University of Chicago, Chicago, 60637, IL, United States
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12
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Schultz HD. Advances in cellular and integrative control of oxygen and carbon dioxide homeostasis. J Physiol 2018; 596:2933-2934. [PMID: 30239019 PMCID: PMC6068245 DOI: 10.1113/jp276326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/01/2018] [Indexed: 11/08/2022] Open
Affiliation(s)
- Harold D. Schultz
- Department of Cellular and Integrative PhysiologyUniveristy of Nebraska Medical CenterOmahaNE 68198USA
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