Article
Biology
Caroline B. Ferreira, Talita M. Silva, Phelipe E. Silva, Claudio L. Castro, Catherine Czeisler, Jose J. Otero, Ana C. Takakura, Thiago S. Moreira
Summary: Mutations in the Phox2b gene, specifically the non-polyalanine repeat expansion mutations (NPARM) form, were found to affect respiratory control and the number of certain neurons. This study contributes to our understanding of the neuropathology of congenital central hypoventilation syndrome (CCHS) and provides new evidence for the mechanisms underlying NPARM CCHS.
Article
Physiology
Kirstyn J. Buchholz, Suzanne E. Neumueller, Nicholas J. Burgraff, Matthew R. Hodges, Lawrence Pan, Hubert Forster
Summary: Moderate chronic hypercapnia in healthy adult female goats suppresses acute CO2/[H+] chemosensitivity and reverses the arterial to mixed expired CO2 gradient, suggesting the suppression of vital mechanisms of ventilatory control and the recruitment of additional physiological systems to help buffer excess CO2.
JOURNAL OF APPLIED PHYSIOLOGY
(2022)
Article
Neurosciences
Benjamin J. Narang, Giorgio Manferdelli, Nicolas Bourdillon, Gregoire P. Millet, Tadej Debevec
Summary: Pre-term birth is associated with physiological effects on ventilatory responsiveness, but overall ventilation is similar to term-born individuals under various environmental conditions.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Geriatrics & Gerontology
Belinda Yew, Jung Yun Jang, Shubir Dutt, Yanrong Li, Isabel J. Sible, Aimee Gaubert, Jean K. Ho, Anna E. Blanken, Anisa Marshall, Xingfeng Shao, Danny J. J. Wang, Daniel A. Nation
Summary: This study compared cerebrovascular reactivity (CVR) in cognitively unimpaired older adults and younger adults. The results showed that older adults had lower levels of global CVR under both hypercapnia and hypocapnia compared to younger adults. Region-of-interest analyses revealed attenuated CVR to hypocapnia in select frontal and temporal regions, and lower CVR to hypercapnia in all cortical, limbic, and subcortical regions examined in older adults compared to younger adults. The findings suggest age-related deficits in CVR, especially in vasodilatory responses, even in cognitively unimpaired older adults.
NEUROBIOLOGY OF AGING
(2022)
Article
Neurosciences
Matiram Pun, Andrew E. Beaudin, Jill K. Raneri, Todd J. Anderson, Patrick J. Hanly, Marc J. Poulin
Summary: The primary characteristic of obstructive sleep apnea (OSA) is chronic exposure to intermittent hypoxia (IH) due to repeated upper airway obstruction. Continuous positive airway pressure (CPAP) is the gold-standard treatment of OSA, reducing the acute ventilatory response to hypoxia. CPAP also corrects ancillary features of OSA such as intermittent hypercapnia, negative intrathoracic pressure and surges in sympathetic activity.
EXPERIMENTAL NEUROLOGY
(2021)
Article
Neurosciences
Alex A. Bhogal
Summary: Using BOLD MRI to evaluate changes in cerebrovascular reactivity in the white matter has shown that the response shape may only partially reflect the actual vascular reactivity, potentially influenced by the venous draining topology. This finding suggests implications when attributing diseases mechanisms and/or progression to presumed impaired white matter BOLD-CVR.
Review
Neurosciences
Andrew E. Beaudin, Patrick J. Hanly, Jill K. Raneri, Magdy Younes, Matiram Pun, Todd J. Anderson, Marc J. Poulin
Summary: Exposure to intermittent hypoxia (IH) is believed to increase the risk of cerebrovascular and cardiovascular disease, but sleep accompanied by IH does not significantly alter vascular responses to hypoxia and hypercapnia in healthy young individuals. However, IH sleep does lead to an increased heart rate response to hypoxia upon waking.
EXPERIMENTAL NEUROLOGY
(2022)
Article
Endocrinology & Metabolism
Jinxia (Fiona) Yao, Ho-Ching (Shawn) Yang, James H. Wang, Zhenhu Liang, Thomas M. Talavage, Gregory G. Tamer, Ikbeom Jang, Yunjie Tong
Summary: This study developed a novel analytical method to accurately calculate the arrival time of elevated CO2 at each voxel and used 26 candidate hemodynamic response functions to quantitatively describe the temporal brain reactions to a CO2 stimulus. By improving the traditional method, this approach successfully mapped three perfusion-related parameters: the relative arrival time of blood, the hemodynamic response function, and CVR during a CO2 challenge.
JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM
(2021)
Article
Endocrinology & Metabolism
Ece Su Sayin, James Duffin, Julien Poublanc, Lashmikumar Venkatraghavan, David John Mikulis, Joseph Arnold Fisher, Olivia Sobczyk
Summary: The evaluation of cerebrovascular reactivity (CVR) is a valuable test for assessing vasodilatory reserve. This study aimed to investigate the effects of mild hyperoxia on CVR. The results showed that mild hyperoxia did not significantly affect CVR.
JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM
(2023)
Article
Neurosciences
Monika Jampolska, Kryspin Andrzejewski, Pawel M. Boguszewski, Katarzyna Kaczynska
Summary: Parkinson's disease affects movement control and can also impair respiration, leading to chronic hypoxia and hypercapnia. In this study, we investigated the respiratory response in a PD model and found that baseline ventilation was reduced, but restored with L-DOPA supplementation. This highlights the potential of dopamine supplementation in improving respiratory function in PD.
Article
Geriatrics & Gerontology
Szilvia Kecskes, Akos Menyhart, Ferenc Bari, Eszter Farkas
Summary: This study discovered a decline in cerebrovascular reactivity (CVR) and cellular senescence in the brains of old rats. Additionally, CVR impairment was observed in acute cerebral ischemia. The use of nimodipine showed mixed effects, improving CVR in aging brains but worsening it in acute ischemia.
FRONTIERS IN AGING NEUROSCIENCE
(2023)
Article
Physiology
Joao Paulo Jacob Sabino, Lucas Vaz de Castro Oliveira, Renato Nery Soriano, Marcelo Kwiatkoski, Luiz G. S. Branco, Glauber S. F. da Silva
Summary: The study found that hypercapnia increases endogenous production of H2S in the medullary raphe, and inhibiting the endogenous H2S attenuates the ventilatory response to hypercapnia, indicating excitatory action through the CBS-H2S pathway.
EXPERIMENTAL PHYSIOLOGY
(2021)
Article
Physiology
Celine-Hivda Yegen, Melanie Lambert, Antoine Beurnier, David Montani, Marc Humbert, Carole Planes, Emilie Boncoeur, Nicolas Voituron, Fabrice Antigny
Summary: This study demonstrates that KCNK3/TASK-1 deficiency in rats leads to an enhanced ventilatory response to hypoxia but no changes in response to hypercapnia. The increased hypoxia response in Kcnk3-deficient rats is accompanied by elevated activity in the ventrolateral region of the medulla oblongata and an increased number of c-Fos positive cells in the first central relay of peripheral chemoreceptors and Raphe Obscurus.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2023)
Article
Neurosciences
Hannah Sweetman, Mahmudur Rahman, Aditya Vedantam, Kajana Satkunendrarajah
Summary: Degenerative cervical myelopathy (DCM) is a neurological condition characterized by chronic compression of the cervical spinal cord, leading to impaired limb function. While respiratory dysfunction is not a common symptom of DCM, it can affect the ventilatory response to respiratory challenges. Surgical decompression improves sensorimotor function in DCM, but its impact on respiratory function is unclear. This study evaluates respiratory function and adaptive ventilation in a DCM model, showing that DCM impairs acute adaptive ventilatory ability and surgical decompression does not fully restore it.
EXPERIMENTAL NEUROLOGY
(2024)
Article
Neurosciences
Peiying Liu, Dengrong Jiang, Marilyn Albert, Christopher E. Bauer, Arvind Caprihan, Brian T. Gold, Steven M. Greenberg, Karl G. Helmer, Kay Jann, Gregory Jicha, Pavel Rodriguez, Claudia L. Satizabal, Sudha Seshadri, Herpreet Singh, Jeffrey F. Thompson, Danny J. J. Wang, Hanzhang Lu
Summary: The study evaluated the reliability of CO2-CVR quantification across different studies, including inter-rater consistency, inter-scanner reproducibility, and test-retest repeatability. The results demonstrated good consistency of CO2-CVR in healthy volunteers, indicating its potential use as an imaging biomarker in multi-center studies and clinical trials.
Article
Cardiac & Cardiovascular Systems
Massimo Nardone, Andre L. Teixeira, Anthony Incognito, Tyler D. Vermeulen, Brooke M. Shafer, Philip J. Millar, Glen E. Foster
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
(2020)
Article
Physiology
Jordan D. Bird, Jack K. Leacy, Glen E. Foster, Caroline A. Rickards, Richard J. A. Wilson, Ken D. O'Halloran, Nicholas G. Jendzjowsky, Brandon A. Pentz, Britta R. M. Byman, Scott F. Thrall, Alexandra L. Skalk, Sarah A. Hewitt, Craig D. Steinback, David Burns, Peter Ondrus, Trevor A. Day
Summary: Rapid ascent to high altitude poses challenges of acute hypoxia and acid-base disturbances, which are countered by ventilatory and renal acclimatization. Renal compensation through bicarbonate elimination helps in normalizing arterial pH. The time course and magnitude of these adaptation processes can vary widely between individuals.
JOURNAL OF APPLIED PHYSIOLOGY
(2021)
Editorial Material
Neurosciences
Glen E. Foster
JOURNAL OF PHYSIOLOGY-LONDON
(2021)
Article
Physiology
Joanna R. G. Keough, Michael M. Tymko, Lindsey M. Boulet, Alenna N. Jamieson, Trevor A. Day, Glen E. Foster
Summary: The study aimed to investigate whether experience-dependent effects (EDEs) differ between two different durations of acute isocapnic intermittent hypoxia protocols and found that while there was no evidence of progressive augmentation or post-hypoxia frequency decline, long-term facilitation in ventilation and blood pressure still occurred. The findings suggest that acute isocapnic intermittent hypoxia alone may not elicit all of the EDEs described in animal models, and ventilatory long-term facilitation occurs regardless of the length of hypoxia-normoxia cycles.
EXPERIMENTAL PHYSIOLOGY
(2021)
Article
Physiology
Keisho Katayama, Paolo B. Dominelli, Glen E. Foster, Shalaya Kipp, Michael G. Leahy, Koji Ishida, Andrew William Sheel
Summary: The study found that respiratory modulation of sympathetic vasomotor outflow to skeletal muscles remains intact and is amplified during dynamic exercise, reaching peak amplification at moderate intensity before plateauing at higher exercise intensities.
JOURNAL OF APPLIED PHYSIOLOGY
(2021)
Article
Neurosciences
Anthony Incognito, Andre L. Teixeira, Brooke M. Shafer, Massimo Nardone, Tyler D. Vermeulen, Glen E. Foster, Philip J. Millar
Summary: This study demonstrates that rhythmic handgrip exercise and isocapnic hypoxia induce similar proportions of single-unit inhibition when matched by multiunit sympathoexcitation, indicating that heterogeneous single-unit response patterns are related to the level of sympathoexcitation independent of the stressor type. Interestingly, only 47% of single units behaved consistently across both stressors, suggesting potential for functional specificity within the postganglionic neuronal pool.
JOURNAL OF NEUROPHYSIOLOGY
(2021)
Article
Physiology
Lindsey M. Boulet, Taylor L. Atwater, Courtney Brown, Brooke M. Shafer, Tyler D. Vermeulen, Paul C. Cotton, Trevor A. Day, Glen E. Foster
Summary: The study found differences in the coronary vasodilatory response to hypoxia between males and females, with a paradoxical reduction in coronary blood velocity in males but not females during metaboreflex activation under hypoxic conditions.
EXPERIMENTAL PHYSIOLOGY
(2022)
Article
Neurosciences
Glen E. Foster, Brooke M. Shafer, Conan Shing
Summary: MSNA measurement is crucial for understanding sympathetic nerve activity in humans, and the process of identifying and quantifying sympathetic bursts is often laborious and variable across research labs. A newly developed open-source web application has shown good agreement with manual scoring methods for key MSNA metrics, providing an efficient and standardized approach for data analysis in research studies. This tool has the potential to improve reproducibility and streamline the analysis of MSNA in future studies.
JOURNAL OF NEUROPHYSIOLOGY
(2021)
Article
Physiology
Austin J. White, Lindsey M. Boulet, Brooke M. Shafer, Tyler D. Vermeulen, Taylor L. Atwater, Mike Stembridge, Philip N. Ainslie, Richard J. A. Wilson, Trevor A. Day, Glen E. Foster
Summary: Coronary vasoconstriction with metaboreflex activation is greatest following acute ascent to high altitude and restored to low-altitude levels following 8-9 days of acclimatization.
JOURNAL OF APPLIED PHYSIOLOGY
(2022)
Article
Physiology
Jacquie Baker, Mohammad A. Safarzadeh, Anthony V. Incognito, Nicholas G. Jendzjowsky, Glen E. Foster, Jordan D. Bird, Satish R. Raj, Trevor A. Day, Caroline A. Rickards, Natalia Zubieta-DeUrioste, Usman Alim, Richard J. A. Wilson
Summary: Cerebral hypoxia is a serious consequence of cardiorespiratory illnesses. Measuring the retinal microvasculature provides insights into cerebral microvasculature and potential implications for critical illness. This study demonstrates dynamic regulation of the retina during rapid ascent and prolonged exposure to high altitude, as well as sex-specific differences in retinal microvasculature. The ability to assess intact microvasculature contiguous with the brain has important research and clinical applications.
JOURNAL OF APPLIED PHYSIOLOGY
(2022)
Article
Neurosciences
Brooke M. Shafer, Anthony Incognito, Tyler D. Vermeulen, Massimo Nardone, Andre L. Teixeira, Stephen A. Klassen, Philip J. Millar, Glen E. Foster
Summary: This study reveals the mechanisms of sympathetic long-term facilitation following hypoxia, in which baroreflex resetting shifts the operating points of action potential clusters, reduces asynchronous action potential firing, and increases the contribution of large-amplitude action potentials.
JOURNAL OF PHYSIOLOGY-LONDON
(2022)
Article
Physiology
Leah M. Mann, Jason S. Chan, Sarah A. Angus, Connor J. Doherty, Benjamin P. Thompson, Glen E. Foster, Richard L. Hughson, Paolo B. Dominelli
Summary: Hypercapnic chemosensitivity is influenced by acute exercise, aerobic fitness, and sex. In this study, we found that higher fitness participants did not necessarily have lower chemosensitivity, but males had a higher chemoresponse compared to females. These findings suggest that sex, unlike aerobic fitness, has an impact on peripheral hypercapnic chemosensitivity.
JOURNAL OF APPLIED PHYSIOLOGY
(2022)
Article
Neurosciences
Brooke M. Shafer, Massimo Nardone, Anthony V. Incognito, Tyler D. Vermeulen, Andre L. Teixeira, Philip J. Millar, A. William Sheel, Chris West, Najib Ayas, Glen E. Foster
Summary: Post-hypoxia sympathoexcitation reduces vascular tone and diminishes sympathetic signalling. Blunted sympathetic transduction during acute hypoxia is confirmed, and the effects of hypoxia on the relationship between mean arterial pressure (MAP) and action potential (AP) activity are examined. It is found that MAP changes are blunted during acute hypoxia but restored in recovery, and asynchronous APs elicit smaller MAP changes compared to synchronous APs.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Neurosciences
Michael G. G. Leahy, Shalaya Kipp, Jenna M. M. Benbaruj, Nisha Charkoudian, Glen E. E. Foster, Michael S. S. Koehle, A. William Sheel
Summary: The effects of ageing and female sex hormones on the respiratory muscle metaboreflex are unclear. Our study found that older adults have a heightened pressor response to inspiratory work, and there is no difference in this response between older males and post-menopause females.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Respiratory System
Jordan D. Bird, Scott A. Sands, Raichel M. Alex, Conan L. H. Shing, Brooke M. Shafer, Nicholas G. Jendzjowsky, Richard J. A. Wilson, Trevor A. Day, Glen E. Foster
Summary: This study aimed to assess the effects of biological sex on loop gain and central sleep apnea (CSA) severity during acclimatization to high altitude. The results showed that CSA severity worsened with acclimatization in men but not in women, which may be due to greater increases in loop gain in men.
ANNALS OF THE AMERICAN THORACIC SOCIETY
(2023)
Article
Physiology
Alyssa R. Mickle, Jesus D. Penaloza-Aponte, Richard Coffey, Natale A. Hall, David Baekey, Erica A. Dale
Summary: Closed-loop epidural stimulation (CL-ES) can improve respiratory deficits caused by cervical spinal cord injury, restoring diaphragm activity and enhancing contralateral activity. This treatment has the potential to lead to lasting recovery and device independence.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Shawn Miller Jr, Edgar Juarez Lopez, Jessica M. L. Grittner, Brendan J. Dougherty
Summary: This study tested the impact of CO2 supplementation at different concentrations on ventilatory long-term facilitation (vLTF) in rats and found that 2% CO2 supplementation during and after acute, intermittent hypoxia (AIH) was sufficient to maintain isocapnia and induce significant vLTF.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Behnam Vafadari, Yoshitaka Oku, Charlotte Tacke, Ali Harb, Swen Huelsmann
Summary: The preBo·tzinger Complex (preBo·tC) in the brainstem plays a critical role in generating respiratory rhythm. This study aimed to investigate the activity of inhibitory glycinergic neurons in the preBo·tC of anesthetized mice. Using juxtacellular recordings and optogenetic activation, the researchers were able to identify and characterize the activity pattern of these inhibitory neurons in relation to the breathing rhythm.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Stephen M. Johnson, Maia G. Gumnit, Sarah M. Johnson, Tracy L. Baker, Jyoti J. Watters
Summary: Low-level activation of mu-opioid receptors can increase the amplitude of inspiratory bursts in neonatal rat brainstem-spinal cord preparations. Endomorphin-2, an endogenous ligand for these receptors, was found to have similar effects. Disinhibition of inhibitory synaptic transmission may not be involved in the changes induced by endomorphin-2, and different mechanisms may underlie the increase in burst amplitude and decrease in burst frequency.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Raphael Martins de Abreu, Beatrice Cairo, Patricia Rehder-Santos, Claudio Donisete da Silva, Etore De Favari Signini, Juliana Cristina Milan-Mattos, Camila Akemi Sakaguchi, Aparecida Maria Catai, Alberto Porta
Summary: The purpose of this study was to determine the association between exercise capacity based on peak oxygen uptake (VO2peak) and resting cardiorespiratory coupling (CRC) levels. The results showed that resting CRC values were associated with exercise capacity in athletes but not in non-athletes.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Sarah M. Russel, Raluca E. Gosman, Katherine Gonzalez, Joshua Wright, Dennis O. Frank-Ito
Summary: This study aimed to characterize the response of different nasal morphologies to airflow-related variables during rapid/deep inspiration. The results showed that notched nasal vestibules had higher resistance values and airflow velocities, while standard nasal vestibules had higher mucosal heat flux. Different nasal phenotypes may predispose individuals to exercise-induced rhinitis.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Ivan Poliacek, Lukas Martvon, Michal Simera, Marcel Veternik, Jakub Misek, Lucia Cibulkova, Kimberly E. Iceman, Donald C. Bolser, Teresa Pitts
Summary: An animal model study evaluated the effects of an abdominal incision on cough and swallow, revealing that abdominal wall manipulations can increase pharyngeal muscle activity during swallow without affecting the cough reflex. Swallowing tended to occur more during the inspiratory phase. The results highlight the important role of abdominal wall sensory feedback in regulating swallow motor patterns.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Rui Yu, Tatsuma Okazaki, Yuzhuo Ren, Junko Okuyama, Satoru Ebihara, Shin-Ichi Izumi
Summary: Body postures significantly influence respiratory muscle force, cough pressure, subjective ease of coughing, and pulmonary function. The 60-degree semi-recumbent posture and sitting posture show better results compared to the supine posture.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Suzuna Sato, Koji Ishida, Noriko I. Tanaka, Keisho Katayama
Summary: Respiratory muscle endurance training has beneficial effects on whole-body endurance performance. A novel high-intensity interval (HII) protocol is found to enhance the efficacy of respiratory muscle training programs.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Letter
Physiology
R. Arieli
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Correction
Physiology
Ivan Poliacek, Michal Simera, Marcel Veternik, Zuzana Kotmanova, Teresa Pitts, Jan Hanacek, Jana Plevkova, Peter Machac, Nadezda Visnovcova, Jakub Misek, Jan Jakus
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
Article
Physiology
Dimitrios I. Bourdas, Nickos D. Geladas
Summary: This study examined the effects of breath-hold training on the performance of novice and elite breath-hold divers. The results showed that breath-hold training significantly improved red blood cell concentration, hemoglobin oxygen saturation steady state duration, and breath-hold time in novice divers. Elite divers had better breath-hold performance and higher peak mean arterial pressure compared to novices. The study suggests that breath-hold training can enhance the performance of divers.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2024)
