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Ahmadian M, Erskine E, Wainman L, Wearing OH, Duffy JS, Stewart LC, Hoiland RL, Taki A, Perim RR, Mitchell GS, Little JP, Mueller PJ, Foster GE, West CR. Acute intermittent hypoxia elicits sympathetic neuroplasticity independent of peripheral chemoreflex activation and spinal cord tissue hypoxia in a rodent model of high-thoracic spinal cord injury. Exp Neurol 2025; 384:115054. [PMID: 39547501 DOI: 10.1016/j.expneurol.2024.115054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2024] [Revised: 11/06/2024] [Accepted: 11/09/2024] [Indexed: 11/17/2024]
Abstract
The loss of medullary control of spinal circuits controlling the heart and blood vessels is a unifying mechanism linking both hemodynamic instability and the risk for cardiovascular diseases (CVD) following spinal cord injury (SCI). As such, new avenues to regulate sympathetic activity are essential to mitigate CVD in this population. Acute intermittent hypoxia (AIH) induces a type of neuroplasticity known as long-term facilitation (LTF), a persistent increase in nerve activity post-AIH in spinal motor circuits. Whether LTF occurs within the sympathetic circuit following SCI is largely unknown. We aimed to test whether AIH elicits sympathetic LTF (i.e., sLTF) and attenuates hypoactivity in sub-lesional splanchnic sympathetic circuits in a male rat model of SCI. In 3 experimental series, we tested whether 1) high-thoracic contusion SCI induces hypoactivity in splanchnic sympathetic nerve activity, 2) AIH elicits sLTF following SCI, and 3) sLTF requires carotid chemoreflex activation or spinal cord tissue hypoxia. Our results indicate that a single-session of AIH therapy (10 × 1 min of FiO2 = 0.1, interspersed with 2 min of FiO2 = 1.0) delivered at 2 weeks following SCI attenuates SCI-induced sympathetic hypoactivity by eliciting sLTF 90 min post-treatment that is independent of peripheral chemoreflex activation and/or spinal cord hypoxia. These findings advance our mechanistic understanding of AIH in the field and yield new insights into factors underpinning AIH-induced sLTF following SCI in a rat model. Our findings also set the stage for the chronic application of AIH to alleviate secondary complications resulting from sympathetic hypoactivity following SCI.
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Affiliation(s)
- Mehdi Ahmadian
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, BC, Canada; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Erin Erskine
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Liisa Wainman
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Oliver H Wearing
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Jennifer S Duffy
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Liam C Stewart
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Ryan L Hoiland
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Alissa Taki
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Raphael R Perim
- Department of Physiology and Pharmacology, College of Osteopathic Medicine, Marian University, Indianapolis, IN, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Centre, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Jonathan P Little
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Patrick J Mueller
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Glen E Foster
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Christopher R West
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada; Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada; Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
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Suleiman A, Wongtangman K, Eikermann M, Stucke AG. Neuroanatomical and pharmaco-physiological effects of hypoxia and esketamine on breathing, the sympathetic nerve system, and cortical function. Br J Anaesth 2024:S0007-0912(24)00686-X. [PMID: 39694753 DOI: 10.1016/j.bja.2024.11.011] [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: 10/24/2024] [Revised: 11/01/2024] [Accepted: 11/04/2024] [Indexed: 12/20/2024] Open
Abstract
Acute hypoxic ventilatory response is an important reflex that helps maintain breathing during low oxygen levels, but it is attenuated by most general anaesthetics. Analgesic doses of ketamine and esketamine are known to have respiratory stimulant effects. In their recent study in the British Journal of Anaesthesia, Jansen and colleagues show that low-dose esketamine preserved the acute hypoxic ventilatory response, while increasing breathing rate, systolic blood pressure, and heart rate. Participants also exhibited higher levels of alertness and unpleasant psychotropic effects compared with the control condition. We review the pharmaco-physiological effects of acute hypoxia and its interactions with esketamine. We provide a summary of the effects of hypoxia and esketamine on the neurocircuitry that leads to arousal, activation of the sympathetic nerve system, and increased drive to upper airway dilator and respiratory pump muscles.
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Affiliation(s)
- Aiman Suleiman
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Karuna Wongtangman
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Matthias Eikermann
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA; Klinik fu¨r Ana¨sthesiologie und Intensivmedizin, Universita¨t Duisburg-Essen, Essen, Germany.
| | - Astrid G Stucke
- Medical College of Wisconsin and WI Children's Wisconsin, Milwaukee, WI, USA
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3
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Moreira TS, Mulkey DK, Takakura AC. Update on vascular control of central chemoreceptors. Exp Physiol 2024; 109:1837-1843. [PMID: 38153366 PMCID: PMC11522829 DOI: 10.1113/ep091329] [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: 10/31/2023] [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.
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Affiliation(s)
- Thiago S. Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias BiomedicasUniversidade de Sao PauloSao PauloBrazil
| | - Daniel K. Mulkey
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsConnecticutUSA
| | - Ana C. Takakura
- Department of Pharmacology, Instituto de Ciencias BiomedicasUniversidade de Sao PauloSão PauloBrazil
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Nuding SC, Segers LS, Iceman KE, 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. J Neurophysiol 2024; 132:1315-1329. [PMID: 39259892 PMCID: PMC11495181 DOI: 10.1152/jn.00032.2024] [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: 02/05/2024] [Revised: 08/20/2024] [Accepted: 09/11/2024] [Indexed: 09/13/2024] Open
Abstract
Hypoxia can trigger a sequence of breathing-related behaviors, from augmentation to apneusis to apnea and gasping. Gasping is 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 hypotheses that hypoxia-evoked gasps are amplified through a disinhibitory microcircuit within the inspiratory neuron chain and that this drive is distributed via an efference copy mechanism. This generates coordinated gasplike discharges concurrently in other circuits of the raphe-pontomedullary respiratory network. Data were obtained from six 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. Neuron spike trains were recorded at multiple pontomedullary sites simultaneously and evaluated for firing rate modulations and short-timescale correlations indicative of functional connectivity. Experimental perturbations evoked reconfiguration of raphe-pontomedullary circuits during initial augmentation, apneusis and augmented bursts, apnea, and gasping. Functional connectivity, altered firing rates, efference copy of gasp drive, and coordinated incremental blood pressure increases support a distributed brain stem network model for amplification and broadcasting of inspiratory drive during autoresuscitative gasping. Gasping begins with a reduction in inhibition by expiratory neurons and an initial loss of inspiratory drive during hypoxic apnea and culminates in autoresuscitative efforts. NEW & NOTEWORTHY Severe hypoxia evokes a sequence of breathing-related behaviors culminating in gasping. We report firing rate modulations and short-timescale correlations in spike trains recorded simultaneously in the raphe-pontomedullary respiratory network during hypoxia. Our findings support a disinhibitory microcircuit and a distributed efference copy mechanism for amplification of gasping. Coordinated increments in blood pressure lead to a model for autoresuscitative bootstrapping of peripheral chemoreceptor reflexes, breathing, and sympathetic activity, complementing and extending prior work.
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Affiliation(s)
- Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Kimberly E Iceman
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Russell O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Jay B Dean
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Pierina A Valarezo
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Dale Shuman
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Irene C Solomon
- Department of Physiology and Biophysics, Renaissance School of Medicine at Stony Brook University, Stony Brook, New York, United States
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
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Silveira AF, Santos MB, Collange NZ, Hayashi CY, Vilela GHF, Almeida SLSD, Andrade JBCD, Rojas S, Moraes FMD, Veiga VC, Flato UAP, Russo TL, Silva GS. Intracranial compliance in patients with COVID-19: a multicenter observational study. ARQUIVOS DE NEURO-PSIQUIATRIA 2024; 82:1-8. [PMID: 39121935 DOI: 10.1055/s-0044-1788669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2024]
Abstract
BACKGROUND Patients with severe coronavirus disease-19 (COVID-19) may require the use of invasive mechanical ventilation (MV) for prolonged periods. Aggressive MV parameters have been associated with changes in intracranial pressure (ICP) in patients with acute intracranial disorders. Significant ICP elevation could compromise intracranial compliance (ICC) and cerebrovascular hemodynamics (CVH). However, the effects of these parameters in individuals without neurological disorders have not yet been evaluated. OBJECTIVE To evaluate ICC in patients on MV with COVID-19 infection compared to other diagnoses, to better characterize the effects of MV and COVID-19 upon ICC. We also compared between the ICC in patients with COVID-19 who did not require MV and healthy volunteers, to assess the isolated effect of COVID-19 upon ICC. METHODS This was an exploratory, observational study with a convenience sample. The ICC was evaluated with a noninvasive ICP monitoring device. The P2/P1 ratio was calculated by dividing the amplitude of these two points, being defined as "abnormal" when P2 > P1. The statistical analysis was performed using a mixed linear model with random effects to compare the P2/P1 ratio in all four groups on the first monitoring day. RESULTS A convenience sample of 78 subjects (15 MV-COVID-19, 15 MV non-COVID-19, 24 non-MV-COVID-19, and 24 healthy participants) was prospectively enrolled. There was no difference in P2/P1 ratios between MV patients with and without COVID-19, nor between non-MV patients with COVID-19 and healthy volunteers. However, the P2/P1 ratio was higher in COVID-19 patients with MV use than in those without it. CONCLUSION This exploratory analysis suggests that COVID-19 does not impair ICC.
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Affiliation(s)
- Ana Flávia Silveira
- Universidade Federal de São Carlos, Departamento de Fisioterapia, São Carlos SP, Brazil
| | - Marcella Barreto Santos
- Universidade Federal de São Paulo, Departamento de Neurologia e Neurocirurgia, São Paulo SP, Brazil
| | - Nelci Zanon Collange
- Universidade Federal de São Paulo, Departamento de Neurologia e Neurocirurgia, São Paulo SP, Brazil
- Centro de Neurocirurgia Pediátrica (CENEPE), São Paulo SP, Brazil
| | | | | | | | - João Brainer Clares de Andrade
- Universidade Federal de São Paulo, Departamento de Neurologia e Neurocirurgia, São Paulo SP, Brazil
- Centro Universitário São Camilo, São Paulo SP, Brazil
| | - Salómon Rojas
- Beneficência Portuguesa Hospital, Divisão da Unidade de Terapia Intensiva Neurológica, São Paulo SP, Brazil
| | - Fabiano Moulin de Moraes
- Universidade Federal de São Paulo, Departamento de Neurologia e Neurocirurgia, São Paulo SP, Brazil
| | - Viviane Cordeiro Veiga
- Beneficência Portuguesa Hospital, Divisão da Unidade de Terapia Intensiva Neurológica, São Paulo SP, Brazil
| | - Uri Adrian Prync Flato
- Hospital Samaritano, Américas Serviços Médicos, Unidade de Terapia Intensiva Geral, São Paulo SP, Brazil
| | - Thiago Luiz Russo
- Universidade Federal de São Carlos, Departamento de Fisioterapia, São Carlos SP, Brazil
| | - Gisele Sampaio Silva
- Universidade Federal de São Paulo, Departamento de Neurologia e Neurocirurgia, São Paulo SP, Brazil
- Hospital Israelita Albert Einstein, Departamento de Neurologia, São Paulo SP, Brazil
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Kazemi K, Abiri A, Zhou Y, Rahmani A, Khayat RN, Liljeberg P, Khine M. Improved sleep stage predictions by deep learning of photoplethysmogram and respiration patterns. Comput Biol Med 2024; 179:108679. [PMID: 39033682 DOI: 10.1016/j.compbiomed.2024.108679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 07/23/2024]
Abstract
Sleep staging is a crucial tool for diagnosing and monitoring sleep disorders, but the standard clinical approach using polysomnography (PSG) in a sleep lab is time-consuming, expensive, uncomfortable, and limited to a single night. Advancements in sensor technology have enabled home sleep monitoring, but existing devices still lack sufficient accuracy to inform clinical decisions. To address this challenge, we propose a deep learning architecture that combines a convolutional neural network and bidirectional long short-term memory to accurately classify sleep stages. By supplementing photoplethysmography (PPG) signals with respiratory sensor inputs, we demonstrated significant improvements in prediction accuracy and Cohen's kappa (k) for 2- (92.7 %; k = 0.768), 3- (80.2 %; k = 0.714), 4- (76.8 %, k = 0.550), and 5-stage (76.7 %, k = 0.616) sleep classification using raw data. This relatively translatable approach, with a less intensive AI model and leveraging only a few, inexpensive sensors, shows promise in accurately staging sleep. This has potential for diagnosing and managing sleep disorders in a more accessible and practical manner, possibly even at home.
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Affiliation(s)
| | - Arash Abiri
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA, United States
| | - Yongxiao Zhou
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA, United States
| | - Amir Rahmani
- Department of Computer Science, University of California, Irvine, Irvine, CA, United States; School of Nursing, University of California, Irvine, Irvine, CA, United States
| | - Rami N Khayat
- Division of Pulmonary and Critical Care Medicine, The UCI Comprehensive Sleep Center, University of California. Irvine, Newport Beach, CA, United States
| | | | - Michelle Khine
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA, United States.
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7
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Schwalbe DC, Stornetta DS, Abraham-Fan RJ, Souza GMPR, Jalil M, Crook ME, Campbell JN, Abbott SBG. Molecular Organization of Autonomic, Respiratory, and Spinally-Projecting Neurons in the Mouse Ventrolateral Medulla. J Neurosci 2024; 44:e2211232024. [PMID: 38918066 PMCID: PMC11293450 DOI: 10.1523/jneurosci.2211-23.2024] [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: 11/28/2023] [Revised: 06/05/2024] [Accepted: 06/11/2024] [Indexed: 06/27/2024] Open
Abstract
The ventrolateral medulla (VLM) is a crucial region in the brain for visceral and somatic control, serving as a significant source of synaptic input to the spinal cord. Experimental studies have shown that gene expression in individual VLM neurons is predictive of their function. However, the molecular and cellular organization of the VLM has remained uncertain. This study aimed to create a comprehensive dataset of VLM cells using single-cell RNA sequencing in male and female mice. The dataset was enriched with targeted sequencing of spinally-projecting and adrenergic/noradrenergic VLM neurons. Based on differentially expressed genes, the resulting dataset of 114,805 VLM cells identifies 23 subtypes of neurons, excluding those in the inferior olive, and five subtypes of astrocytes. Spinally-projecting neurons were found to be abundant in seven subtypes of neurons, which were validated through in situ hybridization. These subtypes included adrenergic/noradrenergic neurons, serotonergic neurons, and neurons expressing gene markers associated with premotor neurons in the ventromedial medulla. Further analysis of adrenergic/noradrenergic neurons and serotonergic neurons identified nine and six subtypes, respectively, within each class of monoaminergic neurons. Marker genes that identify the neural network responsible for breathing were concentrated in two subtypes of neurons, delineated from each other by markers for excitatory and inhibitory neurons. These datasets are available for public download and for analysis with a user-friendly interface. Collectively, this study provides a fine-scale molecular identification of cells in the VLM, forming the foundation for a better understanding of the VLM's role in vital functions and motor control.
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Affiliation(s)
- Dana C Schwalbe
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
| | | | | | | | - Maira Jalil
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Maisie E Crook
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - John N Campbell
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
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8
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Wang W, Wu D, Wang H, Zhang Z, Jiang X, Li S, Shi Y, Gao X. Acute Effects of Breath-Hold Conditions on Aerobic Fitness in Elite Rugby Players. Life (Basel) 2024; 14:917. [PMID: 39202660 PMCID: PMC11355650 DOI: 10.3390/life14080917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/09/2024] [Accepted: 07/19/2024] [Indexed: 09/03/2024] Open
Abstract
The effects of face immersion and concurrent exercise on the diving reflex evoked by breath-hold (BH) differ, yet little is known about the combined effects of different BH conditions on aerobic fitness in elite athletes. This study aimed to assess the acute effects of various BH conditions on 18 male elite rugby players (age: 23.5 ± 1.8 years; height: 183.3 ± 3.4 cm; body mass: 84.8 ± 8.5 kg) and identify the BH condition eliciting the greatest aerobic fitness activation. Participants underwent five warm-up conditions: baseline regular breathing, dynamic dry BH (DD), static dry BH (SD), wet dynamic BH (WD), and wet static BH (WS). Significant differences (p < 0.05) were found in red blood cells (RBCs), red blood cell volume (RGB), and hematocrit (HCT) pre- and post-warm-up. Peak oxygen uptake (VO2peak) and relative oxygen uptake (VO2/kgpeak) varied significantly across conditions, with BH groups showing notably higher values than the regular breathing group (p < 0.05). Interaction effects of facial immersion and movement conditions were significant for VO2peak, VO2/kgpeak, and the cardiopulmonary optimal point (p < 0.05). Specifically, VO2peak and peak stroke volume (SVpeak) were significantly higher in the DD group compared to that in other conditions. Increases in VO2peak were strongly correlated with changes in RBCs and HCT induced by DD warm-up (r∆RBC = 0.84, r∆HCT = 0.77, p < 0.01). In conclusion, DD BH warm-up appears to optimize subsequent aerobic performance in elite athletes.
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Affiliation(s)
- Wendi Wang
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing 100061, China; (W.W.); (D.W.); (H.W.)
| | - Dongzhe Wu
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing 100061, China; (W.W.); (D.W.); (H.W.)
- School of Sport Science, Beijing Sport University, Beijing 100084, China
| | - Hao Wang
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing 100061, China; (W.W.); (D.W.); (H.W.)
| | - Zhiqiang Zhang
- Department of Sports and Arts, China Agricultural University, Beijing 100083, China; (Z.Z.); (X.J.); (S.L.); (Y.S.)
| | - Xuming Jiang
- Department of Sports and Arts, China Agricultural University, Beijing 100083, China; (Z.Z.); (X.J.); (S.L.); (Y.S.)
| | - Shufeng Li
- Department of Sports and Arts, China Agricultural University, Beijing 100083, China; (Z.Z.); (X.J.); (S.L.); (Y.S.)
| | - Yongjin Shi
- Department of Sports and Arts, China Agricultural University, Beijing 100083, China; (Z.Z.); (X.J.); (S.L.); (Y.S.)
| | - Xiaolin Gao
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing 100061, China; (W.W.); (D.W.); (H.W.)
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9
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Shafer BM, West CR, Foster GE. Advancements in the neurocirculatory reflex response to hypoxia. Am J Physiol Regul Integr Comp Physiol 2024; 327:R1-R13. [PMID: 38738293 PMCID: PMC11380992 DOI: 10.1152/ajpregu.00237.2023] [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: 10/23/2023] [Revised: 04/16/2024] [Accepted: 04/29/2024] [Indexed: 05/14/2024]
Abstract
Hypoxia is a pivotal factor in the pathophysiology of various clinical conditions, including obstructive sleep apnea, which has a strong association with cardiovascular diseases like hypertension, posing significant health risks. Although the precise mechanisms linking hypoxemia-associated clinical conditions with hypertension remains incompletely understood, compelling evidence suggests that hypoxia induces plasticity of the neurocirculatory control system. Despite variations in experimental designs and the severity, frequency, and duration of hypoxia exposure, evidence from animal and human models consistently demonstrates the robust effects of hypoxemia in triggering reflex-mediated sympathetic activation. Both acute and chronic hypoxia alters neurocirculatory regulation and, in some circumstances, leads to sympathetic outflow and elevated blood pressures that persist beyond the hypoxic stimulus. Dysregulation of autonomic control could lead to adverse cardiovascular outcomes and increase the risk of developing hypertension.
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Affiliation(s)
- Brooke M Shafer
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Christopher R West
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, British Columbia, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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10
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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.
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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
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11
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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.
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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
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12
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Kaur S, Lynch N, Sela Y, Lima JD, Thomas RC, Bandaru SS, Saper CB. Lateral parabrachial FoxP2 neurons regulate respiratory responses to hypercapnia. Nat Commun 2024; 15:4475. [PMID: 38796568 PMCID: PMC11128025 DOI: 10.1038/s41467-024-48773-5] [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: 04/26/2023] [Accepted: 05/10/2024] [Indexed: 05/28/2024] Open
Abstract
About half of the neurons in the parabrachial nucleus (PB) that are activated by CO2 are located in the external lateral (el) subnucleus, express calcitonin gene-related peptide (CGRP), and cause forebrain arousal. We report here, in male mice, that most of the remaining CO2-responsive neurons in the adjacent central lateral (PBcl) and Kölliker-Fuse (KF) PB subnuclei express the transcription factor FoxP2 and many of these neurons project to respiratory sites in the medulla. PBclFoxP2 neurons show increased intracellular calcium during wakefulness and REM sleep and in response to elevated CO2 during NREM sleep. Photo-activation of the PBclFoxP2 neurons increases respiration, whereas either photo-inhibition of PBclFoxP2 or genetic deletion of PB/KFFoxP2 neurons reduces the respiratory response to CO2 stimulation without preventing awakening. Thus, augmenting the PBcl/KFFoxP2 response to CO2 in patients with sleep apnea in combination with inhibition of the PBelCGRP neurons may avoid hypoventilation and minimize EEG arousals.
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Affiliation(s)
- Satvinder Kaur
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Nicole Lynch
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Yaniv Sela
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Janayna D Lima
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Renner C Thomas
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sathyajit S Bandaru
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Clifford B Saper
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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13
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Trevizan-Baú P, Stanić D, Furuya WI, Dhingra RR, Dutschmann M. Neuroanatomical frameworks for volitional control of breathing and orofacial behaviors. Respir Physiol Neurobiol 2024; 323:104227. [PMID: 38295924 DOI: 10.1016/j.resp.2024.104227] [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: 12/07/2023] [Revised: 01/22/2024] [Accepted: 01/25/2024] [Indexed: 02/16/2024]
Abstract
Breathing is the only vital function that can be volitionally controlled. However, a detailed understanding how volitional (cortical) motor commands can transform vital breathing activity into adaptive breathing patterns that accommodate orofacial behaviors such as swallowing, vocalization or sniffing remains to be developed. Recent neuroanatomical tract tracing studies have identified patterns and origins of descending forebrain projections that target brain nuclei involved in laryngeal adductor function which is critically involved in orofacial behavior. These nuclei include the midbrain periaqueductal gray and nuclei of the respiratory rhythm and pattern generating network in the brainstem, specifically including the pontine Kölliker-Fuse nucleus and the pre-Bötzinger complex in the medulla oblongata. This review discusses the functional implications of the forebrain-brainstem anatomical connectivity that could underlie the volitional control and coordination of orofacial behaviors with breathing.
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Affiliation(s)
- Pedro Trevizan-Baú
- The Florey Institute, University of Melbourne, Victoria, Australia; Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Davor Stanić
- The Florey Institute, University of Melbourne, Victoria, Australia
| | - Werner I Furuya
- The Florey Institute, University of Melbourne, Victoria, Australia
| | - Rishi R Dhingra
- The Florey Institute, University of Melbourne, Victoria, Australia; Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Mathias Dutschmann
- The Florey Institute, University of Melbourne, Victoria, Australia; Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, USA.
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Ricordeau F, Chouchou F, Pichot V, Roche F, Petitjean T, Gormand F, Bastuji H, Charbonnier E, Le Cam P, Stauffer E, Rheims S, Peter-Derex L. Impaired post-sleep apnea autonomic arousals in patients with drug-resistant epilepsy. Clin Neurophysiol 2024; 160:1-11. [PMID: 38367308 DOI: 10.1016/j.clinph.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 12/20/2023] [Accepted: 02/04/2024] [Indexed: 02/19/2024]
Abstract
OBJECTIVE Sudden and unexpected deaths in epilepsy (SUDEP) pathophysiology may involve an interaction between respiratory dysfunction and sleep/wake state regulation. We investigated whether patients with epilepsy exhibit impaired sleep apnea-related arousals. METHODS Patients with drug-resistant (N = 20) or drug-sensitive (N = 20) epilepsy and obstructive sleep apnea, as well as patients with sleep apnea but without epilepsy (controls, N = 20) were included. We explored (1) the respiratory arousal threshold based on nadir oxygen saturation, apnea-hypopnea index, and fraction of hypopnea among respiratory events; (2) the cardiac autonomic response to apnea/hypopnea quantified as percentages of changes from the baseline in RR intervals (RRI), high (HF) and low (LF) frequency powers, and LF/HF. RESULTS The respiratory arousal threshold did not differ between groups. At arousal onset, RRI decreased (-9.42%) and LF power (179%) and LF/HF ratio (190%) increased. This was followed by an increase in HF power (118%), p < 0.05. The RRI decrease was lower in drug-resistant (-7.40%) than in drug-sensitive patients (-9.94%) and controls (-10.91%), p < 0.05. LF and HF power increases were higher in drug-resistant (188%/126%) than in drug-sensitive patients (172%/126%) and controls (177%/115%), p < 0.05. CONCLUSIONS Cardiac reactivity following sleep apnea is impaired in drug-resistant epilepsy. SIGNIFICANCE This autonomic dysfunction might contribute to SUDEP pathophysiology.
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Affiliation(s)
- François Ricordeau
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France
| | - Florian Chouchou
- IRISSE Laboratory (EA4075), UFR SHE, University of La Réunion, Le Tampon, France
| | - Vincent Pichot
- SAINBIOSE, INSERM U1059, Saint-Etienne Jean-Monnet University, Mines Saint-Etienne, France; Clinical Physiology and Exercise, Visas Center, Saint Etienne University Hospital, France
| | - Frédéric Roche
- SAINBIOSE, INSERM U1059, Saint-Etienne Jean-Monnet University, Mines Saint-Etienne, France; Clinical Physiology and Exercise, Visas Center, Saint Etienne University Hospital, France
| | - Thierry Petitjean
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Frédéric Gormand
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Hélène Bastuji
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS UMR 5292 / INSERM U1028 and Lyon 1 University, Lyon, France
| | - Eléna Charbonnier
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Pierre Le Cam
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Emeric Stauffer
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Inter-university Laboratoryof Human MovementBiology (LIBM) EA7424, Team « Vascular Biology and Red Blood Cell », Lyon 1 University, Lyon, France; Respiratory Functional Investigation & Physical Activity Department, Hospices Civils de Lyon, Lyon, France
| | - Sylvain Rheims
- Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS UMR 5292 / INSERM U1028 and Lyon 1 University, Lyon, France; Lyon 1 University, Lyon, France
| | - Laure Peter-Derex
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS UMR 5292 / INSERM U1028 and Lyon 1 University, Lyon, France; Lyon 1 University, Lyon, France.
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15
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Hofmann GC, Gama de Barcellos Filho P, Khodadadi F, Ostrowski D, Kline DD, Hasser EM. Vagotomy blunts cardiorespiratory responses to vagal afferent stimulation via pre- and postsynaptic effects in the nucleus tractus solitarii. J Physiol 2024; 602:1147-1174. [PMID: 38377124 DOI: 10.1113/jp285854] [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: 10/26/2023] [Accepted: 01/29/2024] [Indexed: 02/22/2024] Open
Abstract
Viscerosensory information travels to the brain via vagal afferents, where it is first integrated within the brainstem nucleus tractus solitarii (nTS), a critical contributor to cardiorespiratory function and site of neuroplasticity. We have shown that decreasing input to the nTS via unilateral vagus nerve transection (vagotomy) induces morphological changes in nTS glia and reduces sighs during hypoxia. The mechanisms behind post-vagotomy changes are not well understood. We hypothesized that chronic vagotomy alters cardiorespiratory responses to vagal afferent stimulation via blunted nTS neuronal activity. Male Sprague-Dawley rats (6 weeks old) underwent right cervical vagotomy caudal to the nodose ganglion, or sham surgery. After 1 week, rats were anaesthetized, ventilated and instrumented to measure mean arterial pressure (MAP), heart rate (HR), and splanchnic sympathetic and phrenic nerve activity (SSNA and PhrNA, respectively). Vagal afferent stimulation (2-50 Hz) decreased cardiorespiratory parameters and increased neuronal Ca2+ measured by in vivo photometry and in vitro slice imaging of nTS GCaMP8m. Vagotomy attenuated both these reflex and neuronal Ca2+ responses compared to shams. Vagotomy also reduced presynaptic Ca2+ responses to stimulation (Cal-520 imaging) in the nTS slice. The decrease in HR, SSNA and PhrNA due to nTS nanoinjection of exogenous glutamate also was tempered following vagotomy. This effect was not restored by blocking excitatory amino acid transporters. However, the blunted responses were mimicked by NMDA, not AMPA, nanoinjection and were associated with reduced NR1 subunits in the nTS. Altogether, these results demonstrate that vagotomy induces multiple changes within the nTS tripartite synapse that influence cardiorespiratory reflex responses to afferent stimulation. KEY POINTS: Multiple mechanisms within the nucleus tractus solitarii (nTS) contribute to functional changes following vagal nerve transection. Vagotomy results in reduced cardiorespiratory reflex responses to vagal afferent stimulation and nTS glutamate nanoinjection. Blunted responses occur via reduced presynaptic Ca2+ activation and attenuated NMDA receptor expression and function, leading to a reduction in nTS neuronal activation. These results provide insight into the control of autonomic and respiratory function, as well as the plasticity that can occur in response to nerve damage and cardiorespiratory disease.
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Affiliation(s)
- Gabrielle C Hofmann
- Comparative Medicine, University of Missouri, Columbia, Missouri, USA
- Area Pathobiology, University of Missouri, Columbia, Missouri, USA
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Procopio Gama de Barcellos Filho
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Fateme Khodadadi
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Daniela Ostrowski
- Department of Pharmacology, A.T. Still University, Kirksville, Missouri, USA
| | - David D Kline
- Area Pathobiology, University of Missouri, Columbia, Missouri, USA
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - Eileen M Hasser
- Area Pathobiology, University of Missouri, Columbia, Missouri, USA
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
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Jia X, Sun J, Zhuo Q, Zhao B, Liu Y. Effect of the NLRP3 inflammasome on increased hypoxic ventilation response after CIH exposure in mice. Respir Physiol Neurobiol 2024; 321:104204. [PMID: 38128772 DOI: 10.1016/j.resp.2023.104204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/27/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Chronic intermittent hypoxia (CIH) increases the hypoxic ventilation response (HVR). The downstream cytokine IL-1β of the NLRP3 inflammasome regulates respiration by acting on the carotid body (CB) and neurons in the respiratory center, but the effect of the NLRP3 inflammasome on HVR induced by CIH remains unclear. OBJECTIVE To investigate the effect of NLRP3 on the increased HVR and spontaneous apnea events and duration induced by CIH, the expression and localization of NLRP3 in the respiratory regulatory center of the rostral ventrolateral medulla (RVLM), and the effect of CIH on the activation of the NLRP3 inflammasome in the RVLM. METHODS Eighteen male, 7-week-old C57BL/6 N mice and eighteen male, 7-week-old C57BL/6 N NLRP3 knockout mice were randomly divided into CON-WT, CON-NLRP3-/-, CIH-WT and CIH-NLRP3-/- groups. Respiratory changes in mice were continuously detected using whole-body plethysmography. The expression and localization of the NLRP3 protein and the formation of apoptosis-associated speck-like protein containing CARD (ASC) specks were detected using immunofluorescence staining. RESULTS NLRP3 knockout reduced the increased HVR and the incidence and duration of spontaneous apnea events associated with CIH. The increase in HVR caused by CIH partially recovered after reoxygenation. After CIH, NLRP3 inflammasome activation in the RVLM, which is related to respiratory regulation after hypoxia, increased, which was consistent with the trend of the ventilation response. CONCLUSION The NLRP3 inflammasome may be involved in the increase in the HVR and the incidence and duration of spontaneous apnea induced by CIH. NLRP3 inhibitors may help reduce the increase in the HVR after CIH, which is important for ensuring sleep quality at night in patients with obstructive sleep apnea.
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Affiliation(s)
- Xinyun Jia
- Department of Respiratory, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China; Life Science Research Center, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China
| | - Jianxia Sun
- Department of Respiratory, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China; Life Science Research Center, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China
| | - Qingya Zhuo
- Department of Respiratory, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China; Life Science Research Center, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China
| | - Baosheng Zhao
- Department of Thoracic Surgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui 453100, Henan, China
| | - Yuzhen Liu
- Department of Respiratory, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China; Life Science Research Center, The First Affiliated Hospital of Xinxiang Medical University, 88 Jiankang Road, Weihui 453100, Henan, China; Department of Thoracic Surgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui 453100, Henan, China.
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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.
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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.
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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.
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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.
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19
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SheikhBahaei S, Marina N, Rajani V, Kasparov S, Funk GD, Smith JC, Gourine AV. Contributions of carotid bodies, retrotrapezoid nucleus neurons and preBötzinger complex astrocytes to the CO 2 -sensitive drive for breathing. J Physiol 2024; 602:223-240. [PMID: 37742121 PMCID: PMC10841148 DOI: 10.1113/jp283534] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/06/2023] [Indexed: 09/25/2023] Open
Abstract
Current models of respiratory CO2 chemosensitivity are centred around the function of a specific population of neurons residing in the medullary retrotrapezoid nucleus (RTN). However, there is significant evidence suggesting that chemosensitive neurons exist in other brainstem areas, including the rhythm-generating region of the medulla oblongata - the preBötzinger complex (preBötC). There is also evidence that astrocytes, non-neuronal brain cells, contribute to central CO2 chemosensitivity. In this study, we reevaluated the relative contributions of the RTN neurons, the preBötC astrocytes, and the carotid body chemoreceptors in mediating the respiratory responses to CO2 in experimental animals (adult laboratory rats). To block astroglial signalling via exocytotic release of transmitters, preBötC astrocytes were targeted to express the tetanus toxin light chain (TeLC). Bilateral expression of TeLC in preBötC astrocytes was associated with ∼20% and ∼30% reduction of the respiratory response to CO2 in conscious and anaesthetized animals, respectively. Carotid body denervation reduced the CO2 respiratory response by ∼25%. Bilateral inhibition of RTN neurons transduced to express Gi-coupled designer receptors exclusively activated by designer drug (DREADDGi ) by application of clozapine-N-oxide reduced the CO2 response by ∼20% and ∼40% in conscious and anaesthetized rats, respectively. Combined blockade of astroglial signalling in the preBötC, inhibition of RTN neurons and carotid body denervation reduced the CO2 -induced respiratory response by ∼70%. These data further support the hypothesis that the CO2 -sensitive drive to breathe requires inputs from the peripheral chemoreceptors and several central chemoreceptor sites. At the preBötC level, astrocytes modulate the activity of the respiratory network in response to CO2 , either by relaying chemosensory information (i.e. they act as CO2 sensors) or by enhancing the preBötC network excitability to chemosensory inputs. KEY POINTS: This study reevaluated the roles played by the carotid bodies, neurons of the retrotrapezoid nucleus (RTN) and astrocytes of the preBötC in mediating the CO2 -sensitive drive to breathe. The data obtained show that disruption of preBötC astroglial signalling, blockade of inputs from the peripheral chemoreceptors or inhibition of RTN neurons similarly reduce the respiratory response to hypercapnia. These data provide further support for the hypothesis that the CO2 -sensitive drive to breathe is mediated by the inputs from the peripheral chemoreceptors and several central chemoreceptor sites.
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Affiliation(s)
- Shahriar SheikhBahaei
- Centre for Cardiovascular and Metabolic Neuroscience, Research Department of Neuroscience Physiology and Pharmacology, University College London, London WC1E 6BT, UK
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, 20892 MD, USA
- present address: Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, 20892 MD, USA
| | - Nephtali Marina
- Centre for Cardiovascular and Metabolic Neuroscience, Research Department of Neuroscience Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Vishaal Rajani
- Department of Physiology, Neuroscience & Mental Health Institute, Women and Children’s Health Research Institute, University of Alberta, T6G 2E1, Canada
- present address: Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Sergey Kasparov
- Department of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | - Gregory D. Funk
- Department of Physiology, Neuroscience & Mental Health Institute, Women and Children’s Health Research Institute, University of Alberta, T6G 2E1, Canada
| | - Jeffrey C. Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, 20892 MD, USA
| | - Alexander V. Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Research Department of Neuroscience Physiology and Pharmacology, University College London, London WC1E 6BT, UK
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20
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Hao X, Yang Y, Liu J, Zhang D, Ou M, Ke B, Zhu T, Zhou C. The Modulation by Anesthetics and Analgesics of Respiratory Rhythm in the Nervous System. Curr Neuropharmacol 2024; 22:217-240. [PMID: 37563812 PMCID: PMC10788885 DOI: 10.2174/1570159x21666230810110901] [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: 11/23/2022] [Revised: 04/27/2023] [Accepted: 02/28/2023] [Indexed: 08/12/2023] Open
Abstract
Rhythmic eupneic breathing in mammals depends on the coordinated activities of the neural system that sends cranial and spinal motor outputs to respiratory muscles. These outputs modulate lung ventilation and adjust respiratory airflow, which depends on the upper airway patency and ventilatory musculature. Anesthetics are widely used in clinical practice worldwide. In addition to clinically necessary pharmacological effects, respiratory depression is a critical side effect induced by most general anesthetics. Therefore, understanding how general anesthetics modulate the respiratory system is important for the development of safer general anesthetics. Currently used volatile anesthetics and most intravenous anesthetics induce inhibitory effects on respiratory outputs. Various general anesthetics produce differential effects on respiratory characteristics, including the respiratory rate, tidal volume, airway resistance, and ventilatory response. At the cellular and molecular levels, the mechanisms underlying anesthetic-induced breathing depression mainly include modulation of synaptic transmission of ligand-gated ionotropic receptors (e.g., γ-aminobutyric acid, N-methyl-D-aspartate, and nicotinic acetylcholine receptors) and ion channels (e.g., voltage-gated sodium, calcium, and potassium channels, two-pore domain potassium channels, and sodium leak channels), which affect neuronal firing in brainstem respiratory and peripheral chemoreceptor areas. The present review comprehensively summarizes the modulation of the respiratory system by clinically used general anesthetics, including the effects at the molecular, cellular, anatomic, and behavioral levels. Specifically, analgesics, such as opioids, which cause respiratory depression and the "opioid crisis", are discussed. Finally, underlying strategies of respiratory stimulation that target general anesthetics and/or analgesics are summarized.
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Affiliation(s)
- Xuechao Hao
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yaoxin Yang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Mengchan Ou
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Bowen Ke
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
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21
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Amorim MR, Wang X, Aung O, Bevans-Fonti S, Anokye-Danso F, Ribeiro C, Escobar J, Freire C, Pho H, Dergacheva O, Branco LGS, Ahima RS, Mendelowitz D, Polotsky VY. Leptin signaling in the dorsomedial hypothalamus couples breathing and metabolism in obesity. Cell Rep 2023; 42:113512. [PMID: 38039129 PMCID: PMC10804286 DOI: 10.1016/j.celrep.2023.113512] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 10/25/2023] [Accepted: 11/14/2023] [Indexed: 12/03/2023] Open
Abstract
Mismatch between CO2 production (Vco2) and respiration underlies the pathogenesis of obesity hypoventilation. Leptin-mediated CNS pathways stimulate both metabolism and breathing, but interactions between these functions remain elusive. We hypothesized that LEPRb+ neurons of the dorsomedial hypothalamus (DMH) regulate metabolism and breathing in obesity. In diet-induced obese LeprbCre mice, chemogenetic activation of LEPRb+ DMH neurons increases minute ventilation (Ve) during sleep, the hypercapnic ventilatory response, Vco2, and Ve/Vco2, indicating that breathing is stimulated out of proportion to metabolism. The effects of chemogenetic activation are abolished by a serotonin blocker. Optogenetic stimulation of the LEPRb+ DMH neurons evokes excitatory postsynaptic currents in downstream serotonergic neurons of the dorsal raphe (DR). Administration of retrograde AAV harboring Cre-dependent caspase to the DR deletes LEPRb+ DMH neurons and abolishes metabolic and respiratory responses to leptin. These findings indicate that LEPRb+ DMH neurons match breathing to metabolism through serotonergic pathways to prevent obesity-induced hypoventilation.
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Affiliation(s)
- Mateus R Amorim
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA; Department of Anesthesiology and Critical Care Medicine, George Washington University, Washington, DC 20037, USA.
| | - Xin Wang
- Department of Pharmacology and Physiology, George Washington University, Washington, DC 20037, USA
| | - O Aung
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA
| | - Shannon Bevans-Fonti
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA; Department of Anesthesiology and Critical Care Medicine, George Washington University, Washington, DC 20037, USA
| | | | - Caitlin Ribeiro
- Department of Pharmacology and Physiology, George Washington University, Washington, DC 20037, USA
| | - Joan Escobar
- Department of Pharmacology and Physiology, George Washington University, Washington, DC 20037, USA
| | - Carla Freire
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA
| | - Huy Pho
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA
| | - Olga Dergacheva
- Department of Pharmacology and Physiology, George Washington University, Washington, DC 20037, USA
| | - Luiz G S Branco
- University of São Paulo, Ribeirão Preto, São Paulo 14040-904, Brazil
| | - Rexford S Ahima
- Department of Medicine, Johns Hopkins University, Baltimore, MD 21224, 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; 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.
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22
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Bhandare AM, Dale N. Neural correlate of reduced respiratory chemosensitivity during chronic epilepsy. Front Cell Neurosci 2023; 17:1288600. [PMID: 38193031 PMCID: PMC10773801 DOI: 10.3389/fncel.2023.1288600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024] Open
Abstract
While central autonomic, cardiac, and/or respiratory dysfunction underlies sudden unexpected death in epilepsy (SUDEP), the specific neural mechanisms that lead to SUDEP remain to be determined. In this study, we took advantage of single-cell neuronal Ca2+ imaging and intrahippocampal kainic acid (KA)-induced chronic epilepsy in mice to investigate progressive changes in key cardiorespiratory brainstem circuits during chronic epilepsy. Weeks after induction of status epilepticus (SE), when mice were experiencing recurrent spontaneous seizures (chronic epilepsy), we observed that the adaptive ventilatory responses to hypercapnia were reduced for 5 weeks after SE induction with its partial recovery at week 7. These changes were paralleled by alterations in the chemosensory responses of neurons in the retrotrapezoid nucleus (RTN). Neurons that displayed adapting responses to hypercapnia were less prevalent and exhibited smaller responses over weeks 3-5, whereas neurons that displayed graded responses to hypercapnia became more prevalent by week 7. Over the same period, chemosensory responses of the presympathetic rostral ventrolateral medullary (RVLM) neurons showed no change. Mice with chronic epilepsy showed enhanced sensitivity to seizures, which invade the RTN and possibly put the chemosensory circuits at further risk of impairment. Our findings establish a dysfunctional breathing phenotype with its RTN neuronal correlate in mice with chronic epilepsy and suggest that the assessment of respiratory chemosensitivity may have the potential for identifying people at risk of SUDEP.
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Affiliation(s)
- Amol M. Bhandare
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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23
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Lee QN, Chen JE, Wheeler GJ, Fan AP. Characterizing systemic physiological effects on the blood oxygen level dependent signal of resting-state fMRI in time-frequency space using wavelets. Hum Brain Mapp 2023; 44:6537-6551. [PMID: 37950750 PMCID: PMC10681653 DOI: 10.1002/hbm.26533] [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: 04/25/2023] [Revised: 09/27/2023] [Accepted: 10/19/2023] [Indexed: 11/13/2023] Open
Abstract
Systemic physiological dynamics, such as heart rate variability (HRV) and respiration volume per time (RVT), are known to account for significant variance in the blood oxygen level dependent (BOLD) signal of resting-state functional magnetic resonance imaging (rsfMRI). However, synchrony between these cardiorespiratory changes and the BOLD signal could be due to neuronal (i.e., autonomic activity inducing changes in heart rate and respiration) or vascular (i.e., cardiorespiratory activity facilitating hemodynamic changes and thus the BOLD signal) effects and the contributions of these effects may differ spatially, temporally, and spectrally. In this study, we characterize these brain-body dynamics using a wavelet analysis in rapidly sampled rsfMRI data with simultaneous pulse oximetry and respiratory monitoring of the Human Connectome Project. Our time-frequency analysis across resting-state networks (RSNs) revealed differences in the coherence of the BOLD signal and heartbeat interval (HBI)/RVT dynamics across frequencies, with unique profiles per network. Somatomotor (SMN), visual (VN), and salience (VAN) networks demonstrated the greatest synchrony with both systemic physiological signals when compared to other networks; however, significant coherence was observed in all RSNs regardless of direct autonomic involvement. Our phase analysis revealed distinct frequency profiles of percentage of time with significant coherence between BOLD and systemic physiological signals for different phase offsets across RSNs, suggesting that the phase offset and temporal order of signals varies by frequency. Lastly, our analysis of temporal variability of coherence provides insight on potential influence of autonomic state on brain-body communication. Overall, the novel wavelet analysis enables an efficient characterization of the dynamic relationship between cardiorespiratory activity and the BOLD signal in spatial, temporal, and spectral dimensions to inform our understanding of autonomic states and improve our interpretation of the BOLD signal.
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Affiliation(s)
- Quimby N. Lee
- Department of NeurologyUniversity of California‐Davis, School of MedicineDavisCaliforniaUSA
| | - Jingyuan E. Chen
- Athinoula A. Martinos Center for Biomedical ImagingMassachusetts General HospitalBostonMassachusettsUSA
- Department of RadiologyHarvard Medical SchoolBostonMassachusettsUSA
| | - Gregory J. Wheeler
- Department of Biomedical EngineeringUniversity of California‐DavisDavisCaliforniaUSA
| | - Audrey P. Fan
- Department of NeurologyUniversity of California‐Davis, School of MedicineDavisCaliforniaUSA
- Department of Biomedical EngineeringUniversity of California‐DavisDavisCaliforniaUSA
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24
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Georgescu T. The role of maternal hormones in regulating autonomic functions during pregnancy. J Neuroendocrinol 2023; 35:e13348. [PMID: 37936545 DOI: 10.1111/jne.13348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 11/09/2023]
Abstract
Offspring development relies on numerous physiological changes that occur in a mother's body, with hormones driving many of these adaptations. Amongst these, the physiological functions controlled by the autonomic nervous system are required for the mother to survive and are adjusted to meet the demands of the growing foetus and to ensure a successful birth. The hormones oestrogen, progesterone, and lactogenic hormones rise significantly during pregnancy, suggesting they may also play a role in regulating the maternal adaptations linked to autonomic nervous system functions, including respiratory, cardiovascular, and thermoregulatory functions. Indeed, expression of pregnancy hormone receptors spans multiple brain regions known to regulate these physiological functions. This review examines how respiratory, cardiovascular, and thermoregulatory functions are controlled by these pregnancy hormones by focusing on their action on central nervous system circuits. Inadequate adaptations in these systems during pregnancy can give rise to several pregnancy complications, highlighting the importance in understanding the mechanistic underpinnings of these changes and potentially identifying ways to treat pregnancy-associated afflictions using hormones.
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Affiliation(s)
- T Georgescu
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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25
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Tymko MM, Young D, Vergel D, Matenchuk BA, Maier LE, Sivak A, Davenport MH, Steinback CD. The effect of hypoxemia on muscle sympathetic nerve activity and cardiovascular function: a systematic review and meta-analysis. Am J Physiol Regul Integr Comp Physiol 2023; 325:R474-R489. [PMID: 37642283 DOI: 10.1152/ajpregu.00021.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 08/01/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023]
Abstract
We conducted a systematic review and meta-analysis to determine the effect of acute poikilocapnic, high-altitude, and acute isocapnia hypoxemia on muscle sympathetic nerve activity (MSNA) and cardiovascular function. A comprehensive search across electronic databases was performed until June 2021. All observational designs were included: population (healthy individuals); exposures (MSNA during hypoxemia); comparators (hypoxemia severity and duration); outcomes (MSNA; heart rate, HR; and mean arterial pressure, MAP). Sixty-one studies were included in the meta-analysis. MSNA burst frequency increased by a greater extent during high-altitude hypoxemia [P < 0.001; mean difference (MD), +22.5 bursts/min; confidence interval (CI) = -19.20 to 25.84] compared with acute poikilocapnic hypoxemia (P < 0.001; MD, +5.63 bursts/min; CI = -4.09 to 7.17) and isocapnic hypoxemia (P < 0.001; MD, +4.72 bursts/min; CI = -3.37 to 6.07). MSNA burst amplitude was only elevated during acute isocapnic hypoxemia (P = 0.03; standard MD, +0.46 au; CI = -0.03 to 0.90), and MSNA burst incidence was only elevated during high-altitude hypoxemia [P < 0.001; MD, 33.05 bursts/100 heartbeats; CI = -28.59 to 37.51]. Meta-regression analysis indicated a strong relationship between MSNA burst frequency and hypoxemia severity for acute isocapnic studies (P < 0.001) but not acute poikilocapnia (P = 0.098). HR increased by the same extent across each type of hypoxemia [P < 0.001; MD +13.81 heartbeats/min; 95% CI = 12.59-15.03]. MAP increased during high-altitude hypoxemia (P < 0.001; MD, +5.06 mmHg; CI = 3.14-6.99), and acute isocapnic hypoxemia (P < 0.001; MD, +1.91 mmHg; CI = 0.84-2.97), but not during acute poikilocapnic hypoxemia (P = 0.95). Both hypoxemia type and severity influenced sympathetic nerve and cardiovascular function. These data are important for the better understanding of healthy human adaptation to hypoxemia.
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Affiliation(s)
- Michael M Tymko
- Integrative Cerebrovascular and Environmental Physiology SB Laboratory, Department of Human Health and Nutritional Sciences, College of Biological Science, University of Guelph, Guelph, Ontario, Canada
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Desmond Young
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Daniel Vergel
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Brittany A Matenchuk
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sports and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Lauren E Maier
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Allison Sivak
- H.T. Coutts Education and Physical Education Library, University of Alberta, Edmonton, Alberta, Canada
| | - Margie H Davenport
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sports and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Craig D Steinback
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
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26
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Ahmadzadeh E, Polglase GR, Stojanovska V, Herlenius E, Walker DW, Miller SL, Allison BJ. Does fetal growth restriction induce neuropathology within the developing brainstem? J Physiol 2023; 601:4667-4689. [PMID: 37589339 PMCID: PMC10953350 DOI: 10.1113/jp284191] [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: 01/29/2023] [Accepted: 08/04/2023] [Indexed: 08/18/2023] Open
Abstract
Fetal growth restriction (FGR) is a complex obstetric issue describing a fetus that does not reach its genetic growth potential. The primary cause of FGR is placental dysfunction resulting in chronic fetal hypoxaemia, which in turn causes altered neurological, cardiovascular and respiratory development, some of which may be pathophysiological, particularly for neonatal life. The brainstem is the critical site of cardiovascular, respiratory and autonomic control, but there is little information describing how chronic hypoxaemia and the resulting FGR may affect brainstem neurodevelopment. This review provides an overview of the brainstem-specific consequences of acute and chronic hypoxia, and what is known in FGR. In addition, we discuss how brainstem structural alterations may impair functional control of the cardiovascular and respiratory systems. Finally, we highlight the clinical and translational findings of the potential roles of the brainstem in maintaining cardiorespiratory adaptation in the transition from fetal to neonatal life under normal conditions and in response to the pathological environment that arises during development in growth-restricted infants. This review emphasises the crucial role that the brainstem plays in mediating cardiovascular and respiratory responses during fetal and neonatal life. We assess whether chronic fetal hypoxaemia might alter structure and function of the brainstem, but this also serves to highlight knowledge gaps regarding FGR and brainstem development.
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Affiliation(s)
- Elham Ahmadzadeh
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Obstetrics and GynaecologyMonash UniversityClaytonVictoriaAustralia
| | - Graeme R. Polglase
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Obstetrics and GynaecologyMonash UniversityClaytonVictoriaAustralia
| | - Vanesa Stojanovska
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Obstetrics and GynaecologyMonash UniversityClaytonVictoriaAustralia
| | - Eric Herlenius
- Department of Women's and Children's HealthKarolinska InstitutetSolnaSweden
- Astrid Lindgren Children´s HospitalKarolinska University Hospital StockholmSolnaSweden
| | - David W. Walker
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Neurodevelopment in Health and Disease Research Program, School of Health and Biomedical SciencesRoyal Melbourne Institute of Technology (RMIT)MelbourneVictoriaAustralia
| | - Suzanne L. Miller
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Obstetrics and GynaecologyMonash UniversityClaytonVictoriaAustralia
| | - Beth J. Allison
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Obstetrics and GynaecologyMonash UniversityClaytonVictoriaAustralia
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27
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Ruyle BC, Lima-Silveira L, Martinez D, Cummings KJ, Heesch CM, Kline DD, Hasser EM. Paraventricular nucleus projections to the nucleus tractus solitarii are essential for full expression of hypoxia-induced peripheral chemoreflex responses. J Physiol 2023; 601:4309-4336. [PMID: 37632733 DOI: 10.1113/jp284907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/13/2023] [Indexed: 08/28/2023] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) is essential to peripheral chemoreflex neurocircuitry, but the specific efferent pathways utilized are not well defined. The PVN sends dense projections to the nucleus tractus solitarii (nTS), which exhibits neuronal activation following a hypoxic challenge. We hypothesized that nTS-projecting PVN (PVN-nTS) neurons contribute to hypoxia-induced nTS neuronal activation and cardiorespiratory responses. To selectively target PVN-nTS neurons, rats underwent bilateral nTS nanoinjection of retrogradely transported adeno-associated virus (AAV) driving Cre recombinase expression. We then nanoinjected into PVN AAVs driving Cre-dependent expression of Gq or Gi designer receptors exclusively activated by designer drugs (DREADDs) to test the degree that selective activation or inhibition, respectively, of the PVN-nTS pathway affects the hypoxic ventilatory response (HVR) of conscious rats. We used immunohistochemistry for Fos and extracellular recordings to examine how DREADD activation influences PVN-nTS neuronal activation by hypoxia. Pathway activation enhanced the HVR at moderate hypoxic intensities and increased PVN and nTS Fos immunoreactivity in normoxia and hypoxia. In contrast, PVN-nTS inhibition reduced both the HVR and PVN and nTS neuronal activation following hypoxia. To further confirm selective pathway effects on central cardiorespiratory output, rats underwent hypoxia before and after bilateral nTS nanoinjections of C21 to activate or inhibit PVN-nTS terminals. PVN terminal activation within the nTS enhanced tachycardic, sympathetic and phrenic (PhrNA) nerve activity responses to hypoxia whereas inhibition attenuated hypoxia-induced increases in nTS neuronal action potential discharge and PhrNA. The results demonstrate the PVN-nTS pathway enhances nTS neuronal activation and is necessary for full cardiorespiratory responses to hypoxia. KEY POINTS: The hypothalamic paraventricular nucleus (PVN) contributes to peripheral chemoreflex cardiorespiratory responses, but specific PVN efferent pathways are not known. The nucleus tractus solitarii (nTS) is the first integration site of the peripheral chemoreflex, and the nTS receives dense projections from the PVN. Selective GqDREADD activation of the PVN-nTS pathway was shown to enhance ventilatory responses to hypoxia and activation (Fos immunoreactivity (IR)) of nTS neurons in conscious rats, augmenting the sympathetic and phrenic nerve activity (SSNA and PhrNA) responses to hypoxia in anaesthetized rats. Selective GiDREADD inhibition of PVN-nTS neurons attenuates ventilatory responses, nTS neuronal Fos-IR, action potential discharge and PhrNA responses to hypoxia. These results demonstrate that a projection from the PVN to the nTS is critical for full chemoreflex responses to hypoxia.
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Affiliation(s)
- Brian C Ruyle
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
| | - Ludmila Lima-Silveira
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Diana Martinez
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Kevin J Cummings
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Cheryl M Heesch
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - David D Kline
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Eileen M Hasser
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
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Wan HY, Bunsawat K, Amann M. Autonomic cardiovascular control during exercise. Am J Physiol Heart Circ Physiol 2023; 325:H675-H686. [PMID: 37505474 PMCID: PMC10659323 DOI: 10.1152/ajpheart.00303.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/11/2023] [Accepted: 07/23/2023] [Indexed: 07/29/2023]
Abstract
The cardiovascular response to exercise is largely determined by neurocirculatory control mechanisms that help to raise blood pressure and modulate vascular resistance which, in concert with regional vasodilatory mechanisms, promote blood flow to active muscle and organs. These neurocirculatory control mechanisms include a feedforward mechanism, known as central command, and three feedback mechanisms, namely, 1) the baroreflex, 2) the exercise pressor reflex, and 3) the arterial chemoreflex. The hemodynamic consequences of these control mechanisms result from their influence on the autonomic nervous system and subsequent alterations in cardiac output and vascular resistance. Although stimulation of the baroreflex inhibits sympathetic outflow and facilitates parasympathetic activity, central command, the exercise pressor reflex, and the arterial chemoreflex facilitate sympathetic activation and inhibit parasympathetic drive. Despite considerable understanding of the cardiovascular consequences of each of these mechanisms in isolation, the circulatory impact of their interaction, which occurs when various control systems are simultaneously activated (e.g., during exercise at altitude), has only recently been recognized. Although aging and cardiovascular disease (e.g., heart failure, hypertension) have both been recognized to alter the hemodynamic consequences of these regulatory systems, this review is limited to provide a brief overview on the action and interaction of neurocirculatory control mechanisms in health.
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Affiliation(s)
- Hsuan-Yu Wan
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah, United States
| | - Kanokwan Bunsawat
- Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, Utah, United States
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Markus Amann
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah, United States
- Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, Utah, United States
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
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29
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Dempsey JA, Welch JF. Control of Breathing. Semin Respir Crit Care Med 2023; 44:627-649. [PMID: 37494141 DOI: 10.1055/s-0043-1770342] [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: 07/28/2023]
Abstract
Substantial advances have been made recently into the discovery of fundamental mechanisms underlying the neural control of breathing and even some inroads into translating these findings to treating breathing disorders. Here, we review several of these advances, starting with an appreciation of the importance of V̇A:V̇CO2:PaCO2 relationships, then summarizing our current understanding of the mechanisms and neural pathways for central rhythm generation, chemoreception, exercise hyperpnea, plasticity, and sleep-state effects on ventilatory control. We apply these fundamental principles to consider the pathophysiology of ventilatory control attending hypersensitized chemoreception in select cardiorespiratory diseases, the pathogenesis of sleep-disordered breathing, and the exertional hyperventilation and dyspnea associated with aging and chronic diseases. These examples underscore the critical importance that many ventilatory control issues play in disease pathogenesis, diagnosis, and treatment.
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Affiliation(s)
- Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, University of Wisconsin, Madison, Wisconsin
| | - Joseph F Welch
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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30
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Guluzade NA, Huggard JD, Duffin J, Keir DA. A test of the interaction between central and peripheral respiratory chemoreflexes in humans. J Physiol 2023; 601:4591-4609. [PMID: 37566804 DOI: 10.1113/jp284772] [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: 03/30/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
How central and peripheral chemoreceptor drives to breathe interact in humans remains contentious. We measured the peripheral chemoreflex sensitivity to hypoxia (PChS) at various isocapnic CO2 tensions (P C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) to determine the form of the relationship between PChS and centralP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ . Twenty participants (10F) completed three repetitions of modified rebreathing tests with end-tidalP O 2 ${P_{{{\mathrm{O}}_{\mathrm{2}}}}}$ (P ET O 2 ${P_{{\mathrm{ET}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) clamped at 150, 70, 60 and 45 mmHg. End-tidalP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ (P ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ),P ET O 2 ${P_{{\mathrm{ET}}{{\mathrm{O}}_{\mathrm{2}}}}}$ , ventilation (V ̇ $\dot{V}$ E ) and calculated oxygen saturation (SC O2 ) were measured breath-by-breath by gas-analyser and pneumotach. TheV ̇ $\dot{V}$ E -P ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ relationship of repeat-trials were linear-interpolated, combined, averaged into 1 mmHg bins, and fitted with a double-linear function (V ̇ $\dot{V}$ E S, L min-1 mmHg-1 ). PChS was computed at intervals of 1 mmHg ofP ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ as follows: the difference inV ̇ $\dot{V}$ E between the three hypoxic profiles and the hyperoxic profile (∆V ̇ $\dot{V}$ E ) was calculated; three ∆V ̇ $\dot{V}$ E values were plotted against corresponding SC O2 ; and linear regression determined PChS (Lmin-1 mmHg-1 %SC O2 -1 ). These processing steps were repeated at eachP ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ to produce the PChS vs. isocapnicP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ relationship. These were fitted with linear and polynomial functions, and Akaike information criterion identified the best-fit model. One-way repeated measures analysis of variance assessed between-condition differences.V ̇ $\dot{V}$ E S increased (P < 0.0001) with isoxicP ET O 2 ${P_{{\mathrm{ET}}{{\mathrm{O}}_{\mathrm{2}}}}}$ from 3.7 ± 1.5 L min-1 mmHg-1 at 150 mmHg to 4.4 ± 1.8, 5.0 ± 1.6 and 6.0 ± 2.2 Lmin-1 mmHg-1 at 70, 60 and 45 mmHg, respectively. Mean SC O2 fell progressively (99.3 ± 0%, 93.7 ± 0.1%, 90.4 ± 0.1% and 80.5 ± 0.1%; P < 0.0001). In all individuals, PChS increased withP ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ , and this relationship was best described by a linear model in 75%. Despite increasing central chemoreflex activation, PChS increased linearly withP ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ indicative of an additive central-peripheral chemoreflex response. KEY POINTS: How central and peripheral chemoreceptor drives to breathe interact in humans remains contentious. We measured peripheral chemoreflex sensitivity to hypoxia (PChS) at various isocapnic carbon dioxide tensions (P C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) to determine the form of the relationship between PChS and centralP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ . Participants performed three repetitions of modified rebreathing with end-tidalP O 2 ${P_{{{\mathrm{O}}_{\mathrm{2}}}}}$ fixed at 150, 70, 60 and 45 mmHg. PChS was computed at intervals of 1 mmHg of end-tidalP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ (P ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) as follows: the difference inV ̇ $\dot{V}$ E between the three hypoxic profiles and the hyperoxic profile (∆V ̇ $\dot{V}$ E ) was calculated; three ∆V ̇ $\dot{V}$ E values were plotted against corresponding calculated oxygen saturation (SC O2 ); and linear regression determined PChS (Lmin-1 mmHg-1 %SC O2 -1 ). In all individuals, PChS increased withP ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ , and this relationship was best described by a linear (rather than polynomial) model in 15 of 20. Most participants did not exhibit a hypo- or hyper-additive effect of central chemoreceptors on the peripheral chemoreflex indicating that the interaction was additive.
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Affiliation(s)
- Nasimi A Guluzade
- School of Kinesiology, The University of Western Ontario, London, ON, Canada
| | - Joshua D Huggard
- School of Kinesiology, The University of Western Ontario, London, ON, Canada
| | - James Duffin
- Department of Anaesthesia and Pain Management, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Thornhill Research Inc., Toronto, ON, Canada
| | - Daniel A Keir
- School of Kinesiology, The University of Western Ontario, London, ON, Canada
- Toronto General Research Institute, Toronto General Hospital, Toronto, ON, Canada
- Lawson Health Research Institute, London, ON, Canada
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Carr JMJR, Day TA, Ainslie PN, Hoiland RL. The jugular venous-to-arterial P C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ difference during rebreathing and end-tidal forcing: Relationship with cerebral perfusion. J Physiol 2023; 601:4251-4262. [PMID: 37635691 DOI: 10.1113/jp284449] [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: 01/24/2023] [Accepted: 08/11/2023] [Indexed: 08/29/2023] Open
Abstract
We examined two assumptions of the modified rebreathing technique for the assessment of the ventilatory central chemoreflex (CCR) and cerebrovascular CO2 reactivity (CVR), hypothesizing: (1) that rebreathing abolishes the gradient between the partial pressures of arterial and brain tissue CO2 [measured via the surrogate jugular venousP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ and arterialP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ difference (Pjv-a CO2 )] and (2) rebreathing eliminates the capacity of CVR to influence the Pjv-a CO2 difference, and thus affect CCR sensitivity. We also evaluated these variables during two separate dynamic end-tidal forcing (ETF) protocols (termed: ETF-1 and ETF-2), another method of assessing CCR sensitivity and CVR. Healthy participants were included in the rebreathing (n = 9), ETF-1 (n = 11) and ETF-2 (n = 10) protocols and underwent radial artery and internal jugular vein (advanced to jugular bulb) catheterization to collect blood samples. Transcranial Doppler ultrasound was used to measure middle cerebral artery blood velocity (MCAv). The Pjv-a CO2 difference was not abolished during rebreathing (6.2 ± 2.6 mmHg; P < 0.001), ETF-1 (9.3 ± 1.5 mmHg; P < 0.001) or ETF-2 (8.6 ± 1.4 mmHg; P < 0.001). The Pjv-a CO2 difference did not change during the rebreathing protocol (-0.1 ± 1.2 mmHg; P = 0.83), but was reduced during the ETF-1 (-3.9 ± 1.1 mmHg; P < 0.001) and ETF-2 (-3.4 ± 1.2 mmHg; P = 0.001) protocols. Overall, increases in MCAv were associated with reductions in the Pjv-a CO2 difference during ETF (-0.095 ± 0.089 mmHg cm-1 s-1 ; P = 0.001) but not during rebreathing (-0.028 ± 0.045 mmHg · cm-1 · s-1 ; P = 0.067). These findings suggest that, although the Pjv-a CO2 is not abolished during any chemoreflex assessment technique, hyperoxic hypercapnic rebreathing is probably more appropriate to assess CCR sensitivity independent of cerebrovascular reactivity to CO2 . KEY POINTS: Modified rebreathing is a technique used to assess the ventilatory central chemoreflex and is based on the premise that the rebreathing method eliminates the difference between arterial and brain tissueP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ . Therefore, rebreathing is assumed to isolate the ventilatory response to central chemoreflex stimulation from the influence of cerebral blood flow. We assessed these assumptions by measuring arterial and jugular venous bulbP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ and middle cerebral artery blood velocity during modified rebreathing and compared these data against data from another test of the ventilatory central chemoreflex using hypercapnic dynamic end-tidal forcing. The difference between arterial and jugular venous bulbP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ remained present during both rebreathing and end-tidal forcing tests, whereas middle cerebral artery blood velocity was associated with theP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ difference during end-tidal forcing but not rebreathing. These findings offer substantiating evidence that clarifies and refines the assumptions of modified rebreathing tests, enhancing interpretation of future findings.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, AB, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
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32
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Bock JM, Greenlund IM, Somers VK, Baker SE. Sex Differences in Neurovascular Control: Implications for Obstructive Sleep Apnea. Int J Mol Sci 2023; 24:13094. [PMID: 37685900 PMCID: PMC10487948 DOI: 10.3390/ijms241713094] [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: 07/11/2023] [Revised: 08/10/2023] [Accepted: 08/14/2023] [Indexed: 09/10/2023] Open
Abstract
Patients with obstructive sleep apnea (OSA) have a heightened risk of developing cardiovascular diseases, namely hypertension. While seminal evidence indicates a causal role for sympathetic nerve activity in the hypertensive phenotype commonly observed in patients with OSA, no studies have investigated potential sex differences in the sympathetic regulation of blood pressure in this population. Supporting this exploration are large-scale observational data, as well as controlled interventional studies in healthy adults, indicating that sleep disruption increases blood pressure to a greater extent in females relative to males. Furthermore, females with severe OSA demonstrate a more pronounced hypoxic burden (i.e., disease severity) during rapid eye movement sleep when sympathetic nerve activity is greatest. These findings would suggest that females are at greater risk for the hemodynamic consequences of OSA and related sleep disruption. Accordingly, the purpose of this review is three-fold: (1) to review the literature linking sympathetic nerve activity to hypertension in OSA, (2) to highlight recent experimental data supporting the hypothesis of sex differences in the regulation of sympathetic nerve activity in OSA, and (3) to discuss the potential sex differences in peripheral adrenergic signaling that may contribute to, or offset, cardiovascular risk in patients with OSA.
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Affiliation(s)
- Joshua M. Bock
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA; (J.M.B.)
| | - Ian M. Greenlund
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA; (J.M.B.)
| | - Virend K. Somers
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA; (J.M.B.)
| | - Sarah E. Baker
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN 55901, USA
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33
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van Weperen VYH, Ripplinger CM, Vaseghi M. Autonomic control of ventricular function in health and disease: current state of the art. Clin Auton Res 2023; 33:491-517. [PMID: 37166736 PMCID: PMC10173946 DOI: 10.1007/s10286-023-00948-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/20/2023] [Indexed: 05/12/2023]
Abstract
PURPOSE Cardiac autonomic dysfunction is one of the main pillars of cardiovascular pathophysiology. The purpose of this review is to provide an overview of the current state of the art on the pathological remodeling that occurs within the autonomic nervous system with cardiac injury and available neuromodulatory therapies for autonomic dysfunction in heart failure. METHODS Data from peer-reviewed publications on autonomic function in health and after cardiac injury are reviewed. The role of and evidence behind various neuromodulatory therapies both in preclinical investigation and in-use in clinical practice are summarized. RESULTS A harmonic interplay between the heart and the autonomic nervous system exists at multiple levels of the neuraxis. This interplay becomes disrupted in the setting of cardiovascular disease, resulting in pathological changes at multiple levels, from subcellular cardiac signaling of neurotransmitters to extra-cardiac, extra-thoracic remodeling. The subsequent detrimental cycle of sympathovagal imbalance, characterized by sympathoexcitation and parasympathetic withdrawal, predisposes to ventricular arrhythmias, progression of heart failure, and cardiac mortality. Knowledge on the etiology and pathophysiology of this condition has increased exponentially over the past few decades, resulting in a number of different neuromodulatory approaches. However, significant knowledge gaps in both sympathetic and parasympathetic interactions and causal factors that mediate progressive sympathoexcitation and parasympathetic dysfunction remain. CONCLUSIONS Although our understanding of autonomic imbalance in cardiovascular diseases has significantly increased, specific, pivotal mediators of this imbalance and the recognition and implementation of available autonomic parameters and neuromodulatory therapies are still lagging.
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Affiliation(s)
- Valerie Y H van Weperen
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrythmia Center, University of California, 100 Medical Plaza, Suite 660, Los Angeles, CA, 90095, USA
| | | | - Marmar Vaseghi
- Division of Cardiology, Department of Medicine, UCLA Cardiac Arrythmia Center, University of California, 100 Medical Plaza, Suite 660, Los Angeles, CA, 90095, USA.
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Migliaccio GM, Russo L, Maric M, Padulo J. Sports Performance and Breathing Rate: What Is the Connection? A Narrative Review on Breathing Strategies. Sports (Basel) 2023; 11:sports11050103. [PMID: 37234059 DOI: 10.3390/sports11050103] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/27/2023] Open
Abstract
Breathing is a natural and necessary process for humans. At the same time, the respiratory pace and frequency can vary so much, depending on the status of the subject. Specifically, in sports, breathing can have the effect of limiting performance from a physiological point of view, or, on the other hand, breathing can regulate the psychological status of the athletes. Therefore, the aim of this narrative review is to focus on the literature about the physiological and psychological aspects of breathing pace in sports performance, merging these two aspects because they are usually considered split, in order to create a new integrated vision of breathing and sports performance. Voluntary breathing can be divided into a slow or fast pace (VSB and VFB, respectively), and their effects on both the physiological and psychological parameters are very different. VSB can benefit athletes in a variety of ways, not just physically but mentally as well. It can help improve cardiovascular fitness, reduce stress and anxiety, and improve overall health and well-being, allowing athletes to maintain focus and concentration during training and competition. VFB is normal during physical training and competition, but away from training, if it is not voluntary, it can cause feelings of anxiety, panic, dizziness, and lightheadedness and trigger a stress response in the body, affecting the athlete's quality of life. In summary, the role of breathing in the performance of athletes should be considered, although no definitive data are available. The connection between breathing and sports performance is still unclear, but athletes can obtain benefits in focus and concentration using slow breathing strategies.
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Affiliation(s)
| | - Luca Russo
- Department of Human Sciences, Università Telematica degli Studi IUL, 50122 Florence, Italy
| | - Mike Maric
- Department of Performance, Sport Science Lab, 09131 Cagliari, Italy
| | - Johnny Padulo
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, 20133 Milan, Italy
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Kaur S, Nicole L, Sela Y, Lima J, Thomas R, Bandaru S, Saper C. Lateral parabrachial FoxP2 neurons regulate respiratory responses to hypercapnia. RESEARCH SQUARE 2023:rs.3.rs-2865756. [PMID: 37205337 PMCID: PMC10187408 DOI: 10.21203/rs.3.rs-2865756/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Although CGRP neurons in the external lateral parabrachial nucleus (PBelCGRP neurons) are critical for cortical arousal in response to hypercapnia, activating them has little effect on respiration. However, deletion of all Vglut2 expressing neurons in the PBel region suppresses both the respiratory and arousal response to high CO2. We identified a second population of non-CGRP neurons adjacent to the PBelCGRP group in the central lateral, lateral crescent and Kölliker-Fuse parabrachial subnuclei that are also activated by CO2 and project to the motor and premotor neurons that innvervate respiratory sites in the medulla and spinal cord. We hypothesize that these neurons may in part mediate the respiratory response to CO2 and that they may express the transcription factor, Fork head Box protein 2 (FoxP2), which has recently been found in this region. To test this, we examined the role of the PBFoxP2 neurons in respiration and arousal response to CO2, and found that they show cFos expression in response to CO2 exposure as well as increased intracellular calcium activity during spontaneous sleep-wake and exposure to CO2. We also found that optogenetically photo-activating PBFoxP2 neurons increases respiration and that photo-inhibition using archaerhodopsin T (ArchT) reduced the respiratory response to CO2 stimulation without preventing awakening. Our results indicate that PBFoxP2 neurons play an important role in the respiratory response to CO2 exposure during NREM sleep, and indicate that other pathways that also contribute to the response cannot compensate for the loss of the PBFoxP2 neurons. Our findings suggest that augmentation of the PBFoxP2 response to CO2 in patients with sleep apnea in combination with inhibition of the PBelCGRP neurons may avoid hypoventilation and minimize EEG arousals.
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Affiliation(s)
| | | | | | | | | | - Sathyajit Bandaru
- Beth Israel Department of Neurology, Program in Neuroscience and Division of Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Ma-02215
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Giannoni A, Borrelli C, Gentile F, Sciarrone P, Spießhöfer J, Piepoli M, Richerson GB, Floras JS, Coats AJS, Javaheri S, Emdin M, Passino C. Autonomic and respiratory consequences of altered chemoreflex function: clinical and therapeutic implications in cardiovascular diseases. Eur J Heart Fail 2023; 25:642-656. [PMID: 36907827 PMCID: PMC10989193 DOI: 10.1002/ejhf.2819] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/10/2023] [Accepted: 02/26/2023] [Indexed: 03/14/2023] Open
Abstract
The importance of chemoreflex function for cardiovascular health is increasingly recognized in clinical practice. The physiological function of the chemoreflex is to constantly adjust ventilation and circulatory control to match respiratory gases to metabolism. This is achieved in a highly integrated fashion with the baroreflex and the ergoreflex. The functionality of chemoreceptors is altered in cardiovascular diseases, causing unstable ventilation and apnoeas and promoting sympathovagal imbalance, and it is associated with arrhythmias and fatal cardiorespiratory events. In the last few years, opportunities to desensitize hyperactive chemoreceptors have emerged as potential options for treatment of hypertension and heart failure. This review summarizes up to date evidence of chemoreflex physiology/pathophysiology, highlighting the clinical significance of chemoreflex dysfunction, and lists the latest proof of concept studies based on modulation of the chemoreflex as a novel target in cardiovascular diseases.
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Affiliation(s)
- Alberto Giannoni
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
| | | | - Francesco Gentile
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
| | | | - Jens Spießhöfer
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- University of Aachen, Aachen, Germany
| | | | | | - John S Floras
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
| | | | - Shahrokh Javaheri
- Division of Pulmonary and Sleep Medicine, Bethesda North Hospital, Cincinnati, Ohio, Division of Pulmonary, Critical Care and Sleep Medicine, University of Cincinnati, Cincinnati, Ohio, and Division of Cardiology, The Ohio State University, Columbus, Ohio USA
| | - Michele Emdin
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
| | - Claudio Passino
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
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Karim S, Chahal A, Khanji MY, Petersen SE, Somers V. Autonomic Cardiovascular Control in Health and Disease. Compr Physiol 2023; 13:4493-4511. [PMID: 36994768 PMCID: PMC10406398 DOI: 10.1002/cphy.c210037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Autonomic neural control of the cardiovascular system is formed of complex and dynamic processes able to adjust rapidly to mitigate perturbations in hemodynamics and maintain homeostasis. Alterations in autonomic control feature in the development or progression of a multitude of diseases with wide-ranging physiological implications given the neural system's responsibility for controlling inotropy, chronotropy, lusitropy, and dromotropy. Imbalances in sympathetic and parasympathetic neural control are also implicated in the development of arrhythmia in several cardiovascular conditions sparking interest in autonomic modulation as a form of treatment. A number of measures of autonomic function have shown prognostic significance in health and in pathological states and have undergone varying degrees of refinement, yet adoption into clinical practice remains extremely limited. The focus of this contemporary narrative review is to summarize the anatomy, physiology, and pathophysiology of the cardiovascular autonomic nervous system and describe the merits and shortfalls of testing modalities available. © 2023 American Physiological Society. Compr Physiol 13:4493-4511, 2023.
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Affiliation(s)
- Shahid Karim
- Mayo Clinic, Rochester, Minnesota, USA
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
| | - Anwar Chahal
- Mayo Clinic, Rochester, Minnesota, USA
- University of Pennsylvania, Pennsylvania, USA
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
| | - Mohammed Y. Khanji
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
- Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
- Newham University Hospital, Barts Health NHS Trust, London, UK
| | - Steffen E. Petersen
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
- Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
- Health Data Research UK, London, UK
- Alan Turing Institute, London, UK
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Ostrowski D, Heesch CM, Kline DD, Hasser EM. Nucleus tractus solitarii is required for the development and maintenance of phrenic and sympathetic long-term facilitation after acute intermittent hypoxia. Front Physiol 2023; 14:1120341. [PMID: 36846346 PMCID: PMC9949380 DOI: 10.3389/fphys.2023.1120341] [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: 12/09/2022] [Accepted: 01/26/2023] [Indexed: 02/11/2023] Open
Abstract
Exposure to acute intermittent hypoxia (AIH) induces prolonged increases (long term facilitation, LTF) in phrenic and sympathetic nerve activity (PhrNA, SNA) under basal conditions, and enhanced respiratory and sympathetic responses to hypoxia. The mechanisms and neurocircuitry involved are not fully defined. We tested the hypothesis that the nucleus tractus solitarii (nTS) is vital to augmentation of hypoxic responses and the initiation and maintenance of elevated phrenic (p) and splanchnic sympathetic (s) LTF following AIH. nTS neuronal activity was inhibited by nanoinjection of the GABAA receptor agonist muscimol before AIH exposure or after development of AIH-induced LTF. AIH but not sustained hypoxia induced pLTF and sLTF with maintained respiratory modulation of SSNA. nTS muscimol before AIH increased baseline SSNA with minor effects on PhrNA. nTS inhibition also markedly blunted hypoxic PhrNA and SSNA responses, and prevented altered sympathorespiratory coupling during hypoxia. Inhibiting nTS neuronal activity before AIH exposure also prevented the development of pLTF during AIH and the elevated SSNA after muscimol did not increase further during or following AIH exposure. Furthermore, nTS neuronal inhibition after the development of AIH-induced LTF substantially reversed but did not eliminate the facilitation of PhrNA. Together these findings demonstrate that mechanisms within the nTS are critical for initiation of pLTF during AIH. Moreover, ongoing nTS neuronal activity is required for full expression of sustained elevations in PhrNA following exposure to AIH although other regions likely also are important. Together, the data indicate that AIH-induced alterations within the nTS contribute to both the development and maintenance of pLTF.
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Affiliation(s)
- Daniela Ostrowski
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States,Department of Biology, Truman State University, Kirksville, MO, United States
| | - Cheryl M. Heesch
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States
| | - David D. Kline
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Eileen M. Hasser
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States,*Correspondence: Eileen M. Hasser,
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39
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Controls of Central and Peripheral Blood Pressure and Hemorrhagic/Hypovolemic Shock. J Clin Med 2023; 12:jcm12031108. [PMID: 36769755 PMCID: PMC9917827 DOI: 10.3390/jcm12031108] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/17/2023] [Accepted: 01/23/2023] [Indexed: 02/04/2023] Open
Abstract
The pressure exerted on the heart and blood vessels because of blood flow is considered an essential parameter for cardiovascular function. It determines sufficient blood perfusion, and transportation of nutrition, oxygen, and other essential factors to every organ. Pressure in the primary arteries near the heart and the brain is known as central blood pressure (CBP), while that in the peripheral arteries is known as peripheral blood pressure (PBP). Usually, CBP and PBP are correlated; however, various types of shocks and cardiovascular disorders interfere with their regulation and differently affect the blood flow in vital and accessory organs. Therefore, understanding blood pressure in normal and disease conditions is essential for managing shock-related cardiovascular implications and improving treatment outcomes. In this review, we have described the control systems (neural, hormonal, osmotic, and cellular) of blood pressure and their regulation in hemorrhagic/hypovolemic shock using centhaquine (Lyfaquin®) as a resuscitative agent.
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Augusto TRDL, Peroni J, de Vargas W, Santos PC, Dantas W, Padavini RL, Koch R, Saraiva E, Bastos MAV, Müller PDT. Carotid-body modulation through meditation in stage-I hypertensive subjects: Study protocol of a randomized and controlled study. Medicine (Baltimore) 2023; 102:e32295. [PMID: 36607871 PMCID: PMC9829266 DOI: 10.1097/md.0000000000032295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Adjunctive therapy for hypertension is in high demand for clinical research. Therefore, several meta-analyses have provided sufficient evidence for meditation as an adjunct therapy, without being anchored on reliable physiological grounds. Meditation modulates the autonomic nervous system. Herein, we propose a hierarchical-dependent effect for the carotid body (CB) in attenuating blood pressure (BP) and ventilatory variability (VV) fine-tuning due to known nerve connections between the CB, prefrontal brain, hypothalamus, and solitary tract nucleus. The aim of this exploratory study was to investigate the role of CB in the possible decrease in BP and changes in VV that could occur in response to meditation. This was a prospective, single-center, parallel-group, randomized, controlled clinical trial with concealed allocation. Eligible adult subjects of both sexes with stage 1 hypertension will be randomized into 1 of 2 groups: transcendental meditation or a control group. Subjects will be invited to 3 visits after randomization and 2 additional visits after completing 8 weeks of meditation or waiting-list control. Thus, subjects will undergo BP measurements in normoxia and hyperoxia, VV measurements using the Poincaré method at rest and during exercise, and CB activity measurement in the laboratory. The primary outcome of this study was the detection of changes in BP and CB activity after 8 weeks. Our secondary outcome was the detection of changes in the VV at rest and during exercise. We predict that interactions between hyperoxic deactivation of CB and meditation; Will reduce BP beyond stand-alone intervention or alternatively; Meditation will significantly attenuate the effects of hyperoxia as a stand-alone intervention. In addition, VV can be changed, partially mediated by a reduction in CB activity. Trial registration number: ReBEC registry (RBR-55n74zm). Stage: pre-results.
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Affiliation(s)
- Tiago Rodrigues de Lemos Augusto
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Juliana Peroni
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Wandriane de Vargas
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Priscilla Caroll Santos
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Wendel Dantas
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Roberta Lazari Padavini
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Rodrigo Koch
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | | | - Marco Aurélio Vinhosa Bastos
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Paulo de Tarso Müller
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
- * Correspondence: Paulo de Tarso Müller, Laboratory of Respiratory Pathophysiology (LAFIR); Respiratory Division of University Hospital, Federal University of Mato Grosso do Sul (UFMS), Rua Filinto Müller S/N, Vila Ipiranga CEP:79080-090, Campo Grande, Brazil (e-mail: )
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41
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Wiese BM, Alvarez Reyes A, Vanderah TW, Largent-Milnes TM. The endocannabinoid system and breathing. Front Neurosci 2023; 17:1126004. [PMID: 37144090 PMCID: PMC10153446 DOI: 10.3389/fnins.2023.1126004] [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: 12/16/2022] [Accepted: 03/16/2023] [Indexed: 05/06/2023] Open
Abstract
Recent changes in cannabis accessibility have provided adjunct therapies for patients across numerous disease states and highlights the urgency in understanding how cannabinoids and the endocannabinoid (EC) system interact with other physiological structures. The EC system plays a critical and modulatory role in respiratory homeostasis and pulmonary functionality. Respiratory control begins in the brainstem without peripheral input, and coordinates the preBötzinger complex, a component of the ventral respiratory group that interacts with the dorsal respiratory group to synchronize burstlet activity and drive inspiration. An additional rhythm generator: the retrotrapezoid nucleus/parafacial respiratory group drives active expiration during conditions of exercise or high CO2. Combined with the feedback information from the periphery: through chemo- and baroreceptors including the carotid bodies, the cranial nerves, stretch of the diaphragm and intercostal muscles, lung tissue, and immune cells, and the cranial nerves, our respiratory system can fine tune motor outputs that ensure we have the oxygen necessary to survive and can expel the CO2 waste we produce, and every aspect of this process can be influenced by the EC system. The expansion in cannabis access and potential therapeutic benefits, it is essential that investigations continue to uncover the underpinnings and mechanistic workings of the EC system. It is imperative to understand the impact cannabis, and exogenous cannabinoids have on these physiological systems, and how some of these compounds can mitigate respiratory depression when combined with opioids or other medicinal therapies. This review highlights the respiratory system from the perspective of central versus peripheral respiratory functionality and how these behaviors can be influenced by the EC system. This review will summarize the literature available on organic and synthetic cannabinoids in breathing and how that has shaped our understanding of the role of the EC system in respiratory homeostasis. Finally, we look at some potential future therapeutic applications the EC system has to offer for the treatment of respiratory diseases and a possible role in expanding the safety profile of opioid therapies while preventing future opioid overdose fatalities that result from respiratory arrest or persistent apnea.
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Affiliation(s)
- Beth M. Wiese
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States
| | - Angelica Alvarez Reyes
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States
- College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Todd W. Vanderah
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States
| | - Tally M. Largent-Milnes
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States
- *Correspondence: Tally M. Largent-Milnes,
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MacMillan S, Evans AM. AMPK facilitates the hypoxic ventilatory response through non-adrenergic mechanisms at the brainstem. Pflugers Arch 2023; 475:89-99. [PMID: 35680670 PMCID: PMC9816276 DOI: 10.1007/s00424-022-02713-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/29/2022] [Indexed: 01/31/2023]
Abstract
We recently demonstrated that the hypoxic ventilatory response (HVR) is facilitated by the AMP-activated protein kinase (AMPK) in catecholaminergic neural networks that likely lie downstream of the carotid bodies within the caudal brainstem. Here, we further subcategorise the neurons involved, by cross-comparison of mice in which the genes encoding the AMPK-α1 (Prkaa1) and AMPK-α2 (Prkaa2) catalytic subunits were deleted in catecholaminergic (TH-Cre) or adrenergic (PNMT-Cre) neurons. As expected, the HVR was markedly attenuated in mice with AMPK-α1/α2 deletion in catecholaminergic neurons, but surprisingly was modestly augmented in mice with AMPK-α1/α2 deletion in adrenergic neurons when compared against a variety of controls (TH-Cre, PNMT-Cre, AMPK-α1/α2 floxed). Moreover, AMPK-α1/α2 deletion in catecholaminergic neurons precipitated marked hypoventilation and apnoea during poikilocapnic hypoxia, relative to controls, while mice with AMPK-α1/α2 deletion in adrenergic neurons entered relative hyperventilation with reduced apnoea frequency and duration. We conclude, therefore, that AMPK-dependent modulation of non-adrenergic networks may facilitate increases in ventilatory drive that shape the classical HVR, whereas AMPK-dependent modulation of adrenergic networks may provide some form of negative feedback or inhibitory input to moderate HVR, which could, for example, protect against hyperventilation-induced hypocapnia and respiratory alkalosis.
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Affiliation(s)
- Sandy MacMillan
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - A. Mark Evans
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD UK
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43
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Biswas DD, El Haddad L, Sethi R, Huston ML, Lai E, Abdelbarr MM, Mhandire DZ, ElMallah MK. Neuro-respiratory pathology in spinocerebellar ataxia. J Neurol Sci 2022; 443:120493. [PMID: 36410186 PMCID: PMC9808489 DOI: 10.1016/j.jns.2022.120493] [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: 08/21/2022] [Revised: 10/22/2022] [Accepted: 11/09/2022] [Indexed: 11/15/2022]
Abstract
The spinocerebellar ataxias (SCA) are a heterogeneous group of neurodegenerative disorders with an autosomal dominant inheritance. Symptoms include poor coordination and balance, peripheral neuropathy, impaired vision, incontinence, respiratory insufficiency, dysphagia, and dysarthria. Although many patients with SCA have respiratory-related complications, the exact mechanism and extent of this pathology remain unclear. This review aims to provide an update on the recent clinical and preclinical scientific findings on neuropathology causing respiratory insufficiency in SCA.
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Affiliation(s)
- Debolina D Biswas
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA
| | - Léa El Haddad
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA
| | - Ronit Sethi
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA
| | - Meredith L Huston
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA
| | - Elias Lai
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA
| | - Mariam M Abdelbarr
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA
| | - Doreen Z Mhandire
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA
| | - Mai K ElMallah
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Box 2644, Durham, NC 27710, USA.
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Souza GMPR, Stornetta DS, Vitali AJ, Wildner H, Zeilhofer HU, Campbell JN, Abbott SBG. Chemogenetic activation of noradrenergic A5 neurons increases blood pressure and visceral sympathetic activity in adult rats. Am J Physiol Regul Integr Comp Physiol 2022; 323:R512-R531. [PMID: 35993562 PMCID: PMC9602699 DOI: 10.1152/ajpregu.00119.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/28/2022] [Accepted: 08/16/2022] [Indexed: 11/22/2022]
Abstract
In mammals, the pontine noradrenergic system influences nearly every aspect of central nervous system function. A subpopulation of pontine noradrenergic neurons, called A5, are thought to be important in the cardiovascular response to physical stressors, yet their function is poorly defined. We hypothesized that activation of A5 neurons drives a sympathetically mediated increase in blood pressure (BP). To test this hypothesis, we conducted a comprehensive assessment of the cardiovascular effects of chemogenetic stimulation of A5 neurons in male and female adult rats using intersectional genetic and anatomical targeting approaches. Chemogenetic stimulation of A5 neurons in freely behaving rats elevated BP by 15 mmHg and increased cardiac baroreflex sensitivity with a negligible effect on resting HR. Importantly, A5 stimulation had no detectable effect on locomotor activity, metabolic rate, or respiration. Under anesthesia, stimulation of A5 neurons produced a marked elevation in visceral sympathetic nerve activity (SNA) and no change in skeletal muscle SNA, showing that A5 neurons preferentially stimulate visceral SNA. Interestingly, projection mapping indicates that A5 neurons target sympathetic preganglionic neurons throughout the spinal cord and parasympathetic preganglionic neurons throughout in the brainstem, as well as the nucleus of the solitary tract, and ventrolateral medulla. Moreover, in situ hybridization and immunohistochemistry indicate that a subpopulation of A5 neurons coreleases glutamate and monoamines. Collectively, this study suggests A5 neurons are a central modulator of autonomic function with a potentially important role in sympathetically driven redistribution of blood flow from the visceral circulation to critical organs and skeletal muscle.
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Affiliation(s)
- George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia
| | - Alexander J Vitali
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Hanns U Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - John N Campbell
- Department of Biology, University of Virginia, Charlottesville, Virginia
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia
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45
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Takakura AC. A new neuromodulatory mechanism in the lateral hypothalamus regulating the hypercapnic ventilatory response in conscious rats. Exp Physiol 2022; 107:1212-1213. [PMID: 35969214 DOI: 10.1113/ep090733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 08/11/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, SP, 05508-000, Brazil
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46
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Nokes B, Cooper J, Cao M. Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology. Expert Rev Respir Med 2022; 16:917-929. [PMID: 35949101 DOI: 10.1080/17476348.2022.2112669] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Introduction The recent continuous positive airway pressure (CPAP) crisis has highlighted the need for alternative obstructive sleep apnea (OSA) therapies. This article serves to review OSA pathophysiology and how sleep apnea mechanisms may be utilized to individualize alternative treatment options.Areas covered: The research highlighted below focuses on 1) mechanisms of OSA pathogenesis and 2) CPAP alternative therapies based on mechanism of disease. We reviewed PubMed from inception to July 2022 for relevant articles pertaining to OSA pathogenesis, sleep apnea surgery, as well as sleep apnea alternative therapies.Expert opinion: Although the field of individualized OSA treatment is still in its infancy, much has been learned about OSA traits and how they may be targeted based on a patient's physiology and preferences. While CPAP remains the gold-standard for OSA management, several novel alternatives are emerging. CPAP is a universal treatment approach for all severities of OSA. We believe that a personalized approach to OSA treatment beyond CPAP lies ahead. Additional research is needed with respect to implementation and combination of therapies longitudinally, but we are enthusiastic about the future of OSA treatment based on the data presented here.
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Affiliation(s)
- Brandon Nokes
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of California, San Diego, La Jolla, CA, USA.,Section of Sleep Medicine, Veterans Affairs (VA) San Diego Healthcare System, La Jolla, CA, USA
| | - Jessica Cooper
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Michelle Cao
- Division of Pulmonary, Allergy, Critical Care Medicine & Division of Sleep Medicine, Stanford University, Palo Alto, CA, USA
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Olivares MJ, Toledo C, Ortolani D, Ortiz FC, Díaz HS, Iturriaga R, Del Río R. Sleep dysregulation in sympathetic-mediated diseases: implications for disease progression. Sleep 2022; 45:6649852. [DOI: 10.1093/sleep/zsac166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 06/18/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
The autonomic nervous system (ANS) plays an important role in the coordination of several physiological functions including sleep/wake process. Significant changes in ANS activity occur during wake-to-sleep transition maintaining the adequate cardiorespiratory regulation and brain activity. Since sleep is a complex homeostatic function, partly regulated by the ANS, it is not surprising that sleep disruption trigger and/or evidence symptoms of ANS impairment. Indeed, several studies suggest a bidirectional relationship between impaired ANS function (i.e. enhanced sympathetic drive), and the emergence/development of sleep disorders. Furthermore, several epidemiological studies described a strong association between sympathetic-mediated diseases and the development and maintenance of sleep disorders resulting in a vicious cycle with adverse outcomes and increased mortality risk. However, which and how the sleep/wake control and ANS circuitry becomes affected during the progression of ANS-related diseases remains poorly understood. Thus, understanding the physiological mechanisms underpinning sleep/wake-dependent sympathetic modulation could provide insights into diseases involving autonomic dysfunction. The purpose of this review is to explore potential neural mechanisms involved in both the onset/maintenance of sympathetic-mediated diseases (Rett syndrome, congenital central hypoventilation syndrome, obstructive sleep apnoea, type 2 diabetes, obesity, heart failure, hypertension, and neurodegenerative diseases) and their plausible contribution to the generation of sleep disorders in order to review evidence that may serve to establish a causal link between sleep disorders and heightened sympathetic activity.
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Affiliation(s)
- María José Olivares
- Department of Physiology, Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile , Santiago , Chile
| | - Camilo Toledo
- Department of Physiology, 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
| | - Domiziana Ortolani
- Department of Physiology, Laboratory of Cardiorespiratory Control, Pontificia Universidad Católica de Chile , Santiago , Chile
| | - Fernando C Ortiz
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile , Santiago , Chile
| | - Hugo S Díaz
- Department of Physiology, 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
| | - Rodrigo Iturriaga
- Department of Physiology, 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
| | - Rodrigo Del Río
- Department of Physiology, 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
- Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile , Santiago , Chile
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Milloy KM, White MG, Chicilo JOC, Cummings KJ, Pfoh JR, Day TA. Assessing central and peripheral respiratory chemoreceptor interaction in humans. Exp Physiol 2022; 107:1081-1093. [PMID: 35766127 DOI: 10.1113/ep089983] [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: 08/14/2021] [Accepted: 06/16/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? We investigated the interaction between central and peripheral respiratory chemoreceptors in healthy, awake human participants by (a) using a background of step increases in steady-state normoxic fraction of inspired carbon dioxide to alter central chemoreceptor activation and (b) using the transient hypoxia test to target the peripheral chemoreceptors. What is the main finding and its importance? Our data suggests that the central-peripheral respiratory chemoreceptor interaction is additive in minute ventilation and respiratory rate, but hypoadditive in tidal volume. Our study adds important new data in reconciling chemoreceptor interaction in awake healthy humans, and is consistent with previous reports of simple addition in intact rodents and humans. ABSTRACT Arterial blood gas levels are maintained through respiratory chemoreflexes, mediated by central (CCR) in the CNS and peripheral (PCR) chemoreceptors located in the carotid bodies. The interaction between central and peripheral chemoreceptors is controversial, and few studies have investigated this interaction in awake healthy humans, in part due to methodological challenges. We investigated the interaction between the CCRs and PCRs in healthy humans using a transient hypoxia test (three consecutive breaths of 100% N2 ; TT-HVR), which targets the stimulus and temporal domain specificity of the PCRs. TT-HVRs were superimposed upon three randomized background levels of steady-state inspired fraction of normoxic CO2 (FI CO2 ; 0, 0.02 and 0.04). Chemostimuli (calculated oxygen saturation; ScO2 ) and respiratory variable responses (respiratory rate, inspired tidal volume and ventilation; RR , VTI , V̇I ), were averaged from all three TT-HVR trials at each FI CO2 level. Responses were assessed as (a) a change from BL (delta; ∆) and (b) indexed against ∆ScO2 . Aside from a significantly lower ∆VTI response in 0.04 FI CO2 (P = 0.01), the hypoxic rate responses (∆RR or ∆RR /∆ScO2 ; P = 0.46, P = 0.81), hypoxic tidal volume response (∆VTI /∆ScO2 ; P = 0.08) and the hypoxic ventilatory responses (∆V̇I and (∆V̇I /∆ScO2 ; P = 0.09 and P = 0.31) were not significantly different across FI CO2 trials. Our data suggests simple addition between central and peripheral chemoreceptors in V̇I , which is mediated through simple addition in RR responses, but hypo-addition in VTI responses. Our study adds important new data in reconciling chemoreceptor interaction in awake healthy humans, and is consistent with previous reports of simple addition in intact rodents and humans. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Kristin M Milloy
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada
| | - Matthew G White
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada
| | - Janelle O C Chicilo
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada
| | | | - Jamie R Pfoh
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Canada
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Respiratory and heart rate dynamics during peripheral chemoreceptor deactivation compared to targeted sympathetic and sympathetic/parasympathetic (co-)activation. Auton Neurosci 2022; 241:103009. [PMID: 35753247 DOI: 10.1016/j.autneu.2022.103009] [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: 03/10/2022] [Revised: 05/29/2022] [Accepted: 06/13/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND The importance of peripheral chemoreceptors for cardiorespiratory neural control is known for decades. Pure oxygen inhalation deactivates chemoreceptors and increases parasympathetic outflow. However, the relationship between autonomic nervous system (ANS) activation and resulting respiratory as well as heart rate (HR) dynamics is still not fully understood. METHODS In young adults the impact of (1) 100 % pure oxygen inhalation (hyperoxic cardiac chemoreflex sensitivity (CHRS) testing), (2) the cold face test (CFT) and (3) the cold pressor test (CPT) on heart rate variability (HRV), hemodynamics and respiratory rate was investigated in randomized order. Baseline ANS outflow was determined assessing respiratory sinus arrhythmia via deep breathing, baroreflex sensitivity and HRV. RESULTS Baseline ANS outflow was normal in all participants (23 ± 1 years, 7 females, 3 males). Hyperoxic CHRS testing decreased HR (after 60 ± 3 vs before 63 ± 3 min-1, p = 0.004), while increasing total peripheral resistance (1053 ± 87 vs 988 ± 76 dyne*s + m2/cm5, p = 0.02) and mean arterial blood pressure (93 ± 4 vs 91 ± 4 mm Hg, p = 0.02). HRV indicated increased parasympathetic outflow after hyperoxic CHRS testing accompanied by a decrease in respiratory rate (15 ± 1vs 19 ± 1 min-1, p = 0.001). In contrast, neither CFT nor CPT altered the respiratory rate (18 ± 1 vs 18 ± 2 min-1, p = 0.38 and 18 ± 1 vs 18 ± 1 min-1, p = 0.84, respectively). CONCLUSION Changes in HR characteristics during deactivation of peripheral chemoreceptors but not during the CFT and CPT are related with a decrease in respiratory rate. This highlights the need of respiratory rate assessment when evaluating adaptations of cardiorespiratory chemoreceptor control.
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Gu L, Yu Q, Shen Y, Wang Y, Xu Q, Zhang H. The role of monoaminergic neurons in modulating respiration during sleep and the connection with SUDEP. Biomed Pharmacother 2022; 150:112983. [PMID: 35453009 DOI: 10.1016/j.biopha.2022.112983] [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: 02/15/2022] [Revised: 04/04/2022] [Accepted: 04/14/2022] [Indexed: 11/25/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among epilepsy patients, occurring even more frequently in cases with anti-epileptic drug resistance. Despite some advancements in characterizing SUDEP, the underlying mechanism remains incompletely understood. This review summarizes the latest advances in our understanding of the pathogenic mechanisms of SUDEP, in order to identify possible targets for the development of new strategies to prevent SUDEP. Based on our previous research along with the current literature, we focus on the role of sleep-disordered breathing (SDB) and its related neural mechanisms to consider the possible roles of monoaminergic neurons in the modulation of respiration during sleep and the occurrence of SUDEP. Overall, this review suggests that targeting the monoaminergic neurons is a promising approach to preventing SUDEP. The proposed roles of SDB and related monoaminergic neural mechanisms in SUDEP provide new insights for explaining the pathogenesis of SUDEP.
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Affiliation(s)
- LeYuan Gu
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Qian Yu
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Yue Shen
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - YuLing Wang
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Qing Xu
- Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - HongHai Zhang
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310006, China.
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