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Hori A, Fukazawa A, Katanosaka K, Mizuno M, Hotta N. Mechanosensitive channels in the mechanical component of the exercise pressor reflex. Auton Neurosci 2023; 250:103128. [PMID: 37925831 DOI: 10.1016/j.autneu.2023.103128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023]
Abstract
The cardiovascular response is appropriately regulated during exercise to meet the metabolic demands of the active muscles. The exercise pressor reflex is a neural feedback mechanism through thin-fiber muscle afferents activated by mechanical and metabolic stimuli in the active skeletal muscles. The mechanical component of this reflex is referred to as skeletal muscle mechanoreflex. Its initial step requires mechanotransduction mediated by mechanosensors, which convert mechanical stimuli into biological signals. Recently, various mechanosensors have been identified, and their contributions to muscle mechanoreflex have been actively investigated. Nevertheless, the mechanosensitive channels responsible for this muscular reflex remain largely unknown. This review discusses progress in our understanding of muscle mechanoreflex under healthy conditions, focusing on mechanosensitive channels.
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Affiliation(s)
- Amane Hori
- College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan; Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-8472, Japan; Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Ayumi Fukazawa
- Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-8472, Japan; Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Kimiaki Katanosaka
- College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
| | - Masaki Mizuno
- Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Norio Hotta
- College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
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Sprick JD, Jeong J, Sabino-Carvalho JL, Li S, Park J. Neurocirculatory regulation and adaptations to exercise in chronic kidney disease. Am J Physiol Heart Circ Physiol 2023; 324:H843-H855. [PMID: 37000610 PMCID: PMC10191135 DOI: 10.1152/ajpheart.00115.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/01/2023]
Abstract
Chronic kidney disease (CKD) is characterized by pronounced exercise intolerance and exaggerated blood pressure reactivity during exercise. Classic mechanisms of exercise intolerance in CKD have been extensively described previously and include uremic myopathy, chronic inflammation, malnutrition, and anemia. We contend that these classic mechanisms only partially explain the exercise intolerance experienced in CKD and that alterations in cardiovascular and autonomic regulation also play a key contributing role. The purpose of this review is to examine the physiological factors that contribute to neurocirculatory dysregulation during exercise and discuss the adaptations that result from regular exercise training in CKD. Key neurocirculatory mechanisms contributing to exercise intolerance in CKD include augmentation of the exercise pressor reflex, aberrations in neurocirculatory control, and increased neurovascular transduction. In addition, we highlight how some contributing factors may be improved through exercise training, with a specific focus on the sympathetic nervous system. Important areas for future work include understanding how the exercise prescription may best be optimized in CKD and how the beneficial effects of exercise training may extend to the brain.
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Affiliation(s)
- Justin D Sprick
- Department of Kinesiology, Health Promotion and Recreation, University of North Texas, Denton, Texas, United States
| | - Jinhee Jeong
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
| | - Jeann L Sabino-Carvalho
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
| | - Sabrina Li
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
| | - Jeanie Park
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
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Qiu Y, Fernández-García B, Lehmann HI, Li G, Kroemer G, López-Otín C, Xiao J. Exercise sustains the hallmarks of health. JOURNAL OF SPORT AND HEALTH SCIENCE 2023; 12:8-35. [PMID: 36374766 PMCID: PMC9923435 DOI: 10.1016/j.jshs.2022.10.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/10/2022] [Accepted: 09/02/2022] [Indexed: 05/23/2023]
Abstract
Exercise has long been known for its active role in improving physical fitness and sustaining health. Regular moderate-intensity exercise improves all aspects of human health and is widely accepted as a preventative and therapeutic strategy for various diseases. It is well-documented that exercise maintains and restores homeostasis at the organismal, tissue, cellular, and molecular levels to stimulate positive physiological adaptations that consequently protect against various pathological conditions. Here we mainly summarize how moderate-intensity exercise affects the major hallmarks of health, including the integrity of barriers, containment of local perturbations, recycling and turnover, integration of circuitries, rhythmic oscillations, homeostatic resilience, hormetic regulation, as well as repair and regeneration. Furthermore, we summarize the current understanding of the mechanisms responsible for beneficial adaptations in response to exercise. This review aimed at providing a comprehensive summary of the vital biological mechanisms through which moderate-intensity exercise maintains health and opens a window for its application in other health interventions. We hope that continuing investigation in this field will further increase our understanding of the processes involved in the positive role of moderate-intensity exercise and thus get us closer to the identification of new therapeutics that improve quality of life.
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Affiliation(s)
- Yan Qiu
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Cardiac Regeneration and Ageing Lab, Institute of Cardiovascular Sciences, Shanghai Engineering Research Center of Organ Repair, School of Life Science, Shanghai University, Shanghai 200444, China
| | - Benjamin Fernández-García
- Health Research Institute of the Principality of Asturias (ISPA), Oviedo 33011, Spain; Department of Morphology and Cell Biology, Anatomy, University of Oviedo, Oviedo 33006, Spain
| | - H Immo Lehmann
- Cardiovascular Division of the Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Guoping Li
- Cardiovascular Division of the Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris Cité, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris 75231, France; Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif 94805, France; Institut du Cancer Paris CARPEM, Department of Biology, Hôpital Européen Georges Pompidou, AP-HP, Paris 75015, France.
| | - Carlos López-Otín
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología, Universidad de Oviedo, Oviedo 33006, Spain; Centro de Investigación Biomédica en Red Enfermedades Cáncer (CIBERONC), Oviedo 33006, Spain.
| | - Junjie Xiao
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Cardiac Regeneration and Ageing Lab, Institute of Cardiovascular Sciences, Shanghai Engineering Research Center of Organ Repair, School of Life Science, Shanghai University, Shanghai 200444, China.
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Teixeira AL, Vianna LC. The exercise pressor reflex: An update. Clin Auton Res 2022; 32:271-290. [PMID: 35727398 DOI: 10.1007/s10286-022-00872-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/25/2022] [Indexed: 02/07/2023]
Abstract
The exercise pressor reflex is a feedback mechanism engaged upon stimulation of mechano- and metabosensitive skeletal muscle afferents. Activation of these afferents elicits a reflex increase in heart rate, blood pressure, and ventilation in an intensity-dependent manner. Consequently, the exercise pressor reflex has been postulated to be one of the principal mediators of the cardiorespiratory responses to exercise. In this updated review, we will discuss classical and recent advancements in our understating of the exercise pressor reflex function in both human and animal models. Particular attention will be paid to the afferent mechanisms and pathways involved during its activation, its effects on different target organs, its potential role in the abnormal cardiovascular response to exercise in diseased states, and the impact of age and biological sex on these responses. Finally, we will highlight some unanswered questions in the literature that may inspire future investigations in the field.
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Affiliation(s)
- André L Teixeira
- NeuroV̇ASQ̇, Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, DF, Brasília, Brazil
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Lauro C Vianna
- NeuroV̇ASQ̇, Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, DF, Brasília, Brazil.
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Gama G, dos Santos Rangel MV, de Oliveira Coelho VC, Paz GA, de Matos CVB, Silva BP, Lopes GDO, Lopes KG, Farinatti P, Borges JP. The effects of exercise training on autonomic and hemodynamic responses to muscle metaboreflex in people living with HIV/AIDS: A randomized clinical trial protocol. PLoS One 2022; 17:e0265516. [PMID: 35303017 PMCID: PMC8932586 DOI: 10.1371/journal.pone.0265516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/23/2022] [Indexed: 11/24/2022] Open
Abstract
Background People living with HIV (PLHIV) present impaired muscle metaboreflex, which may lead to exercise intolerance and increased cardiovascular risk. The muscle metaboreflex adaptations to exercise training in these patients are unknown. The present study aims to investigate the effects of a supervised multimodal exercise training on hemodynamic and autonomic responses to muscle metaboreflex activation in PLHIV. Methods and design In this randomized clinical trial protocol, 42 PLHIV aged 30–50 years will be randomly assigned at a ratio of 1:1 into an intervention or a control group. The intervention group will perform exercise training (3x/week during 12 weeks) and the control group will remain physically inactive. A reference group composed of 21 HIV-uninfected individuals will be included. Primary outcomes will be blood pressure and heart rate variability indices assessed during resting, mental stress, and activation of muscle metaboreflex by a digital sphygmomanometer and a heart rate monitor; respectively. Mental stress will be induced by the Stroop Color-Word test and muscle metaboreflex will be activated through a post-exercise circulatory arrest (PECA) protocol, being the latter performed without and with the application of a capsaicin-based analgesic balm in the exercised limb. Secondary outcomes will be heart rate, peripheral vascular resistance, stroke volume, cardiac output, blood lactate, anthropometric markers and handgrip maximal voluntary contraction. The intervention and control groups of PLHIV will be evaluated at baseline and after the intervention, while the HIV-uninfected reference group only at baseline. Discussion The findings of the present study may help to elucidate the muscle metaboreflex adaptations to exercise training in PLHIV. Trial registration This study will be performed at University of Rio de Janeiro State following registration at ClinicalTrials.gov as NCT04512456 on August 13, 2020.
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Affiliation(s)
- Gabriel Gama
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Marcus Vinicius dos Santos Rangel
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Vanessa Cunha de Oliveira Coelho
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Gabriela Andrade Paz
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Catarina Vieira Branco de Matos
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Bárbara Pinheiro Silva
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Gabriella de Oliveira Lopes
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Karynne Grutter Lopes
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- Graduate Program in Clinical and Experimental Physiopathology, Faculty of Medical Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Paulo Farinatti
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Juliana Pereira Borges
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- * E-mail:
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Ando S, Takagi Y, Watanabe H, Mochizuki K, Sudo M, Fujibayashi M, Tsurugano S, Sato K. Effects of electrical muscle stimulation on cerebral blood flow. BMC Neurosci 2021; 22:67. [PMID: 34775960 PMCID: PMC8591929 DOI: 10.1186/s12868-021-00670-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/29/2021] [Indexed: 01/16/2023] Open
Abstract
Background Electrical muscle stimulation (EMS) induces involuntary muscle contraction. Several studies have suggested that EMS has the potential to be an alternative method of voluntary exercise; however, its effects on cerebral blood flow (CBF) when applied to large lower limb muscles are poorly understood. Thus, the purpose of this study was to examine the effects of EMS on CBF, focusing on whether the effects differ between the internal carotid (ICA) and vertebral (VA) arteries. Methods The participants performed the experiments under EMS and control (rest) conditions in a randomized crossover design. The ICA and VA blood flow were measured before and during EMS or control. Heart rate, blood pressure, minute ventilation, oxygen uptake, and end-tidal partial pressure of carbon dioxide (PETCO2) were monitored and measured as well. Results The ICA blood flow increased during EMS [Pre: 330 ± 69 mL min−1; EMS: 371 ± 81 mL min−1, P = 0.001, effect size (Cohen’s d) = 0.55]. In contrast, the VA blood flow did not change during EMS (Pre: 125 ± 47 mL min−1; EMS: 130 ± 45 mL min−1, P = 0.26, effect size = 0.12). In the EMS condition, there was a significant positive linear correlation between ΔPETCO2 and ΔICA blood flow (R = 0.74, P = 0.02). No relationships were observed between ΔPETCO2 and ΔVA blood flow (linear: R = − 0.17, P = 0.66; quadratic: R = 0.43, P = 0.55). Conclusions The present results indicate that EMS increased ICA blood flow but not VA blood flow, suggesting that the effects of EMS on cerebral perfusion differ between anterior and posterior cerebral circulation, primarily due to the differences in cerebrovascular response to CO2.
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Affiliation(s)
- Soichi Ando
- Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan.
| | - Yoko Takagi
- Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Hikaru Watanabe
- Faculty of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Kodai Mochizuki
- Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Mizuki Sudo
- Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Tobuki 150, Hachioji, Tokyo, 192-0001, Japan
| | | | - Shinobu Tsurugano
- Health Care Center, The University of Electro-Communication, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Kohei Sato
- Department of Arts and Sport Science, Tokyo Gakugei University, Tokyo, Japan
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Teixeira AL, Fernandes IA, Millar PJ, Vianna LC. GABA A receptor activation modulates the muscle sympathetic nerve activity responses at the onset of static exercise in humans. J Appl Physiol (1985) 2021; 131:1138-1147. [PMID: 34410847 DOI: 10.1152/japplphysiol.00423.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exercise is a well-known sympathoexcitatory stimulus. However, muscle sympathetic nerve activity (MSNA) can decrease during the onset of muscle contraction. Yet, the underlying mechanisms and neurotransmitters involved in the sympathetic responses at the onset of exercise remain unknown. Herein, we tested the hypothesis that GABAA receptors may contribute to the MSNA responses at the onset of static handgrip in humans. Thirteen young, healthy individuals (4 females) performed 30 s of ischemic static handgrip at 30% of maximum volitional contraction before and following oral administration of either placebo or diazepam (10 mg), a benzodiazepine that enhances GABAA activity. MSNA (microneurography), beat-to-beat blood pressure (finger photopletysmography), heart rate (electrocardiogram), and stroke volume (ModelFlow) were continuously measured. Cardiac output (CO = stroke volume × heart rate) and total vascular conductance (TVC = CO/mean blood pressure) were subsequently calculated. At rest, MSNA was reduced while hemodynamic variables were unchanged after diazepam administration. Before diazepam, static handgrip elicited a significant decrease in MSNA burst frequency (Δ-7 ± 2 bursts/min, P < 0.01 vs. baseline) and MSNA burst incidence (Δ-16 ± 2 bursts/100 heart beats, P < 0.01 vs. baseline); however, these responses were attenuated following diazepam administration (Δ-1 ± 2 bursts/min and Δ-7 ± 2 bursts/100 heart beats, respectively; P < 0.01 vs. before diazepam). Diazepam did not affect the increases in heart rate, blood pressure, CO, and TVC at the exercise onset. Importantly, the placebo had no effect on any variable at rest or exercise onset. These findings suggest that GABAA receptor activation modulates the MSNA responses at the onset of static exercise in young, healthy humans.NEW & NOTEWORTHY In this study, we found that the reduction in muscle sympathetic nerve activity at the onset of static handgrip exercise was blunted following GABAA receptor activation with oral administration of diazepam in young, healthy individuals. The present findings provide novel insight into neural circuitry mechanisms controlling muscle sympathetic outflow during exercise in humans.
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Affiliation(s)
- André L Teixeira
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.,NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
| | - Igor A Fernandes
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
| | - Philip J Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Lauro C Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
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Mizuno M, Hotta N, Ishizawa R, Kim HK, Iwamoto G, Vongpatanasin W, Mitchell JH, Smith SA. The Impact of Insulin Resistance on Cardiovascular Control During Exercise in Diabetes. Exerc Sport Sci Rev 2021; 49:157-167. [PMID: 33965976 PMCID: PMC8195845 DOI: 10.1249/jes.0000000000000259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Patients with diabetes display heightened blood pressure response to exercise, but the underlying mechanism remains to be elucidated. There is no direct evidence that insulin resistance (hyperinsulinemia or hyperglycemia) impacts neural cardiovascular control during exercise. We propose a novel paradigm in which hyperinsulinemia or hyperglycemia significantly influences neural regulatory pathways controlling the circulation during exercise in diabetes.
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Affiliation(s)
- Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Norio Hotta
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Gary Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Scott A. Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
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Gama G, Farinatti P, Rangel MVDS, Mira PADC, Laterza MC, Crisafulli A, Borges JP. Muscle metaboreflex adaptations to exercise training in health and disease. Eur J Appl Physiol 2021; 121:2943-2955. [PMID: 34189604 DOI: 10.1007/s00421-021-04756-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/19/2021] [Indexed: 12/11/2022]
Abstract
Abnormalities in the muscle metaboreflex concur to exercise intolerance and greater cardiovascular risk. Exercise training benefits neurocardiovascular function at rest and during exercise, but its role in favoring muscle metaboreflex in health and disease remains controversial. While some authors demonstrated that exercise training enhanced the sensitization of muscle metabolically afferents and improved neurocardiovascular responses to muscle metaboreflex activation, others reported unaltered responses. This narrative review aimed to: (a) highlight the current evidence on the effects of exercise training upon cardiovascular and autonomic responses to muscle metaboreflex activation; (b) analyze the role of training components and indicate potential mechanisms of metaboreflex adaptations; and (c) address key methodological features for future research. Though limited, accumulated evidence suggests that muscle metaboreflex adaptations depend on the individual clinical status, exercise modality, and training duration. In healthy populations, most trials negated the hypothesis of metaboreflex improvement due to chronic exercise, irrespective of the training duration. Favorable changes in patients with impaired metaboreflex, particularly chronic heart failure, mostly resulted from long-term interventions (> 16 weeks) including aerobic exercise of moderate to high intensity, performed in isolation or within multimodal training. Potential mechanisms of metaboreflex improvements include enhanced sensitivity of channels and receptors, greater antioxidant capacity, lower metabolite accumulation, increased functional sympatholysis, and muscle perfusion. Future research should investigate: (1) the dose-response relationship of training components within different exercise modalities to elicit improvements in individuals showing intact or impaired muscle metaboreflex; and (2) potential and specific underlying mechanisms of metaboreflex improvements in individuals with different medical conditions.
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Affiliation(s)
- Gabriel Gama
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rua São Francisco Xavier, 524, sala 8133F, Maracanã, Rio de Janeiro, RJ, CEP, 20550-013, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Paulo Farinatti
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rua São Francisco Xavier, 524, sala 8133F, Maracanã, Rio de Janeiro, RJ, CEP, 20550-013, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
- Graduate Program in Physical Activity Sciences, Salgado de Oliveira University, Niteroi, RJ, Brazil
| | - Marcus Vinicius Dos Santos Rangel
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rua São Francisco Xavier, 524, sala 8133F, Maracanã, Rio de Janeiro, RJ, CEP, 20550-013, Brazil
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil
| | - Pedro Augusto de Carvalho Mira
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, RJ, Brazil
- Cardiovascular Research Unit and Exercise Physiology - InCFEx, University Hospital and Faculty of Physical Education and Sports, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Mateus Camaroti Laterza
- Cardiovascular Research Unit and Exercise Physiology - InCFEx, University Hospital and Faculty of Physical Education and Sports, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Antonio Crisafulli
- Department of Medical Science and Public Health, University of Cagliari, Cagliari, Italy
| | - Juliana Pereira Borges
- Laboratory of Physical Activity and Health Promotion, Institute of Physical Education and Sports, University of Rio de Janeiro State, Rua São Francisco Xavier, 524, sala 8133F, Maracanã, Rio de Janeiro, RJ, CEP, 20550-013, Brazil.
- Graduate Program in Exercise and Sports Sciences, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil.
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Incognito AV, Teixeira AL, Shafer BM, Nardone M, Vermeulen TD, Foster GE, Millar PJ. Muscle sympathetic single-unit responses during rhythmic handgrip exercise and isocapnic hypoxia in males: the role of sympathoexcitation magnitude. J Neurophysiol 2021; 126:170-180. [PMID: 34133241 DOI: 10.1152/jn.00678.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A small proportion of postganglionic muscle sympathetic single units can be inhibited during sympathoexcitatory stressors in humans. However, whether these responses are dependent on the specific stressor or the level of sympathoexcitation remains unclear. We hypothesize that, when matched by sympathoexcitatory magnitude, different stressors can evoke similar proportions of inhibited single units. Multiunit and single-unit muscle sympathetic nerve activity (MSNA) were recorded in seven healthy young males at baseline and during 1) rhythmic handgrip exercise (40% of maximum voluntary contraction) and 2) acute isocapnic hypoxia (partial pressure of end-tidal O2 47 ± 3 mmHg). Single units were classified as activated, nonresponsive, or inhibited if the spike frequency was above, within, or below the baseline variability, respectively. By design, rhythmic handgrip and isocapnic hypoxia similarly increased multiunit total MSNA [Δ273 ± 208 vs. Δ254 ± 193 arbitrary units (AU), P = 0.84] and single-unit spike frequency (Δ8 ± 10 vs. Δ12 ± 13 spikes/min, P = 0.12). Among 19 identified single units, the proportions of activated (47% vs. 68%), nonresponsive (32% vs. 16%), and inhibited (21% vs. 16%) single units were not different between rhythmic handgrip and isocapnic hypoxia (P = 0.42). However, only 9 (47%) single units behaved with concordant response patterns across both stressors (7 activated, 1 nonresponsive, and 1 inhibited during both stressors). During the 1-min epoch with the highest increase in total MSNA during hypoxia (Δ595 ± 282 AU, P < 0.01) only one single unit was inhibited. These findings suggest that the proportions of muscle sympathetic single units inhibited during stress are associated with the level of sympathoexcitation and not the stressor per se in healthy young males.NEW & NOTEWORTHY Subpopulations of muscle sympathetic single units can be inhibited during mild sympathoexcitatory stress. We demonstrate that rhythmic handgrip exercise and isocapnic hypoxia, when matched by multiunit sympathoexcitation, induce similar proportions of single-unit inhibition, highlighting 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 with concordant response patterns between stressors, suggesting the potential for functional specificity within the postganglionic neuronal pool.
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Affiliation(s)
- Anthony V Incognito
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - André L Teixeira
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Brooke M Shafer
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Massimo Nardone
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Tyler D Vermeulen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, 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
| | - Philip J Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.,Toronto General Research Institute, Toronto General Hospital, Toronto, Ontario, Canada
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11
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Sabino-Carvalho JL, Fisher JP, Vianna LC. Autonomic Function in Patients With Parkinson's Disease: From Rest to Exercise. Front Physiol 2021; 12:626640. [PMID: 33815139 PMCID: PMC8017184 DOI: 10.3389/fphys.2021.626640] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 02/24/2021] [Indexed: 12/16/2022] Open
Abstract
Parkinson’s disease (PD) is a common neurodegenerative disorder classically characterized by symptoms of motor impairment (e.g., tremor and rigidity), but also presenting with important non-motor impairments. There is evidence for the reduced activity of both the parasympathetic and sympathetic limbs of the autonomic nervous system at rest in PD. Moreover, inappropriate autonomic adjustments accompany exercise, which can lead to inadequate hemodynamic responses, the failure to match the metabolic demands of working skeletal muscle and exercise intolerance. The underlying mechanisms remain unclear, but relevant alterations in several discrete central regions (e.g., dorsal motor nucleus of the vagus nerve, intermediolateral cell column) have been identified. Herein, we critically evaluate the clinically significant and complex associations between the autonomic dysfunction, fatigue and exercise capacity in PD.
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Affiliation(s)
- Jeann L Sabino-Carvalho
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
| | - James P Fisher
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Lauro C Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil.,Graduate Program in Medical Sciences, Faculty of Medicine, University of Brasília, Brasília, Brazil
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12
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Polito MD, Papst R, Goessler K. Twelve weeks of resistance training performed with different number of sets: Effects on maximal strength and resting blood pressure of individuals with hypertension. Clin Exp Hypertens 2021; 43:164-168. [PMID: 33043697 DOI: 10.1080/10641963.2020.1833024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Objective: This study aimed to verify the effect of resistance training performed with single (SET1) or three sets (SET3) on muscle strength and resting blood pressure (BP) of individuals with hypertension. BP was also assessed during knee extension exercise with submaximal load before and after training. Methods: Thirty-eight patients with hypertension were randomly assigned to a control group (CON: n = 12; 55.6 ± 3.2 years; 65.3 ± 9.3 kg; 163.5 ± 8.6 cm), SET1 group (n = 14; 58.1 ± 2.0 years; 65.4 ± 8.7 kg; 162.4 ± 11.1 cm) or SET3 group (n = 12; 57.9 ± 2.4 years; 66.3 ± 11.4 kg; 161.6 ± 7.5 cm). The training was conducted for 12 weeks (3 d.w-1; 4 exercises; 12-15 repetitions; moderate intensity). Results: No differences were found in pre-training values for BP and strength between groups. After training, SET3 showed lower values than CON for resting systolic (121.3 ± 8.0 vs 129.3 ± 10.3 mmHg; P = .01) and diastolic BP (73.5 ± 6.0 vs 79.5 ± 7.4 mmHg; P = .02). Muscle strength in bench-press and knee extension exercises increased in SET1 (48.1 ± 6.3 and 71.3 ± 12.2 kg, respectively) and SET3 (50.2 ± 7.8 and 75.2 ± 9.6 kg, respectively) in relation to CON (39.3 ± 5.1 and 62.4 ± 9.9 kg) (P < .01). BP during knee extension (70% of one maximal repetition) did not differ between groups either before or after training. Conclusion: Resistance training with a single set could be interesting when there is a need to increase muscle strength without necessarily reducing resting BP. On the other hand, the performance of three sets increased muscle strength and reduced BP at rest in individuals with hypertension.
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Affiliation(s)
- Marcos D Polito
- Physical Education Department, Londrina State University , Londrina, Brazil
| | - Rafael Papst
- Physical Education Department, Londrina State University , Londrina, Brazil
| | - Karla Goessler
- Faculdade de Medicina FMUSP, Universidade de São Paulo , São Paulo, Brazil
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13
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Incognito AV, Samora M, Shepherd AD, Cartafina RA, Guimarães GMN, Daher M, Vianna LC, Millar PJ. Sympathetic arterial baroreflex hysteresis in humans: different patterns during low- and high-pressure levels. Am J Physiol Heart Circ Physiol 2020; 319:H787-H792. [PMID: 32857604 DOI: 10.1152/ajpheart.00505.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fluctuations in diastolic pressure modulate muscle sympathetic nerve activity (MSNA) through the arterial baroreflex. A higher sympathetic baroreflex sensitivity (sBRS) to pressure falls compared with rises has been reported; however, the underlying mechanisms are unclear. We assessed whether beat-to-beat falling and rising diastolic pressures operate on two distinct baroreflex response curves. Twenty-two men (32 ± 8 yr) underwent sequential bolus injections of nitroprusside and phenylephrine (modified Oxford test) with continuous recording of heart rate, blood pressure, and MSNA. The weighted negative linear regression slope between falling or rising diastolic pressure and MSNA burst incidence quantified sBRSfall and sBRSrise, respectively. The diastolic pressure evoking a MSNA burst incidence of 50 (T50) was calculated. sBRSfall was greater than sBRSrise (-6.24 ± 2.80 vs. -4.34 ± 2.16 bursts·100 heartbeats-1·mmHg-1, P = 0.01) and had a narrower operating range (14 ± 8 vs. 20 ± 10 mmHg, P = 0.01) that was shifted rightward (T50, 75 ± 9 and 70 ± 11 mmHg, P < 0.001). At diastolic pressures below baseline, sBRSfall was less than sBRSrise (-1.81 ± 1.31 vs. -3.59 ± 1.70 bursts·100 heartbeats-1·mmHg-1, P = 0.003) as low absolute pressures operated closer to the saturation plateau on the falling, compared with the rising pressure curve. At pressures above baseline, sBRSfall was greater than sBRSrise (-5.23 ± 1.94 and -3.79 ± 1.67 bursts·100 heartbeats-1·mmHg-1, P = 0.03). These findings demonstrate that the sympathetic arterial baroreflex possesses two response curves for processing beat-to-beat diastolic pressure falls and rises. The falling pressure curve is rightward shifted, which reduces sensitivity to falling pressure at low absolute pressures. This demonstrates that the direction of the hysteresis is influenced by the prevailing pressure level relative to each baroreflex response curve.NEW & NOTEWORTHY The findings show that the arterial baroreflex processes diastolic pressure dependent on the direction of pressure change from the previous beat, yielding two distinct baroreflex response curves to falling and rising pressure. Overall, the falling pressure curve is rightward shifted and more sensitive. The rightward shift caused a hysteresis reversal at hypotensive pressures as the falling pressure saturation plateau of the sigmoid response curve occurred at higher pressures than the rising pressure curve.
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Affiliation(s)
- Anthony V Incognito
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.,NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Milena Samora
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Andrew D Shepherd
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Roberta A Cartafina
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | | | - Mauricio Daher
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Lauro C Vianna
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Philip J Millar
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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14
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Samora M, Teixeira AL, Sabino-Carvalho JL, Vianna LC. Sex differences in cardiac vagal reactivation from the end of isometric handgrip exercise and at the onset of muscle metaboreflex isolation. Auton Neurosci 2020; 228:102714. [PMID: 32829151 DOI: 10.1016/j.autneu.2020.102714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/09/2020] [Accepted: 08/07/2020] [Indexed: 11/18/2022]
Abstract
A parasympathetic reactivation is an underlying mechanism mediating the rapid fall in heart rate (HR) at the onset of post-exercise ischemia (PEI) in humans. Herein, we tested the hypothesis that, compared to men, women present a slower HR recovery at the cessation of isometric handgrip exercise (i.e., onset of PEI) due to an attenuated cardiac vagal reactivation. Forty-seven (23 women) young and healthy volunteers were recruited. Subjects performed 90s of isometric handgrip exercise at 40% of maximal voluntary contraction followed by 3-min of PEI. The onset of PEI was analyzed over the first 30s in 10s windows. Cardiac vagal reactivation was indexed using the HR fall and by HR variability metrics (e.g., RMSSD and SDNN) immediately after the cessation of the exercise. HR was significantly increased from rest during exercise in men and women and increases were similar between sexes. However, following the cessation of exercise, the HR recovery was significantly slower in women compared to men regardless of the time point (women vs. men: ∆-14 ± 8 vs. ∆-18 ± 6 beats.min-1 at 10s; ∆-20 ± 9 vs. ∆-25 ± 8 beats.min-1 at 20s; ∆-22 ± 10 vs. ∆-27 ± 9 beats.min-1 at 30s; P = .027). RMSSD and SDNN increased at the cessation of exercise in greater magnitude in men compared to women. These findings demonstrate that women had a slower HR recovery at the cessation of isometric handgrip exercise and onset of PEI compared to men, suggesting a sex-related difference in cardiac vagal reactivation in healthy young humans.
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Affiliation(s)
- Milena Samora
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, DF, Brazil
| | - André L Teixeira
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, DF, Brazil
| | - Jeann L Sabino-Carvalho
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, DF, Brazil
| | - Lauro C Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, DF, Brazil; Graduate Program in Medical Sciences, Faculty of Medicine, University of Brasília, Brasília, DF, Brazil.
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15
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Incognito AV, Nardone M, Teixeira AL, Lee JB, Kathia MM, Millar PJ. Muscle sympathetic single-unit response patterns during progressive muscle metaboreflex activation in young healthy adults. J Neurophysiol 2020; 124:682-690. [PMID: 32727266 DOI: 10.1152/jn.00305.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Muscle sympathetic single units can respond differentially to stress, but whether these responses are linked to the degree of sympathoexcitation is unclear. Fifty-three muscle sympathetic single units (microneurography) were recorded in 17 participants (8 women; 24 ± 3 yr). Five 40-s bouts of 10% static handgrip were performed during a 10-min forearm ischemia to progressively increase metabolite accumulation. Each static handgrip was separated by a 75-s ischemic rest [postexercise circulatory occlusion (PECO)] to assess the isolated action of the muscle metaboreflex. During each set of PECO, individual single units were classified as activated, nonresponsive, or inhibited if the spike frequency was above, within, or below the baseline variability, respectively. From sets 1-5 of PECO, the proportion of single units with activated (34, 45, 68, 87, and 89%), nonresponsive (43, 44, 23, 7, and 9%), or inhibited (23, 11, 9, 6, and 2%) responses changed (P < 0.001) as total muscle sympathoexcitation increased. A total of 51/53 (96%) single units were activated in at least one set of PECO, 16 (31%) initially inhibited before activation. This response pattern delayed the activation onset compared with noninhibited units (set 3 ± 1 vs. 2 ± 1, P < 0.001). Once activated, the spike-frequency rate of rise was similar (8.5 ± 6.5 vs. 7.1 ± 6.0 spikes/min per set, P = 0.48). Muscle sympathetic single-unit firing demonstrated differential control during muscle metaboreflex activation. Single units that were initially inhibited during progressive metaboreflex activation were capable of being activated in later sets. These findings reveal that single-unit activity is influenced by convergent neural inputs (i.e., both inhibitory and excitatory), which yield heterogenous single-unit activation thresholds.NEW & NOTEWORTHY Muscle sympathetic single units respond differentially to sympathoexcitatory stress such that single units can increase firing to contribute to the sympathoexcitatory response or can be nonresponsive or even inhibited. We observed a subgroup of single units that can respond bidirectionally, being first inhibited before activated by progressive increases in forearm muscle metaboreflex activation. These results suggest convergent neural inputs (i.e., inhibitory and excitatory), which yield heterogenous muscle sympathetic single-unit activation thresholds.
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Affiliation(s)
- Anthony V Incognito
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Massimo Nardone
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - André L Teixeira
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jordan B Lee
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Muhammad M Kathia
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Philip J Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.,Toronto General Research Institute, Toronto, Ontario, Canada
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16
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Li Q, Garry MG. A murine model of the exercise pressor reflex. J Physiol 2020; 598:3155-3171. [PMID: 32406099 DOI: 10.1113/jp277602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/30/2020] [Indexed: 12/26/2022] Open
Abstract
KEY POINTS The decerebrate mouse provides a novel working model of the exercise pressor reflex (EPR). The decerebrate mouse model of the EPR is similar to the previously described decerebrate rat model. Studying the EPR in transgenic mouse models can define exact mechanisms of the EPR in health and disease. ABSTRACT The exercise pressor reflex (EPR) is defined by a rise in mean arterial pressure (MAP) and heart rate (HR) in response to exercise and is necessary to match metabolic demand and prevent premature fatigue. While this reflex is readily tested in humans, mechanistic studies are largely infeasible. Here, we have developed a novel murine model of the EPR to allow for mechanistic studies in various mouse models. We observed that ventral root stimulation (VRS) in an anaesthetized mouse causes a depressor response and a reduction in HR. In contrast, the same stimulation in a decerebrate mouse causes a rise in MAP and HR which is abolished by dorsal rhizotomy or by neuromuscular blockade. Moreover, we demonstrate a reduced MAP response to VRS using TRPV1 antagonism or in Trpv1 null mice while the response to passive stretch remains intact. Additionally, we demonstrate that intra-arterial infusion of capsaicin results in a dose-related rise in MAP and HR that is significantly reduced by a selective and potent TRPV1 antagonist or is completely abolished in Trpv1 null mice. These data serve to validate the development of a decerebrate mouse model for the study of cardiovascular responses to exercise and further define the role of the TRPV1 receptor in mediating the EPR. This novel model will allow for extensive study of the EPR in unlimited transgenic and mutant mouse lines, and for an unprecedented exploration of the molecular mechanisms that control cardiovascular responses to exercise in health and disease.
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Affiliation(s)
- Qinglu Li
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mary G Garry
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
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17
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Sabino-Carvalho JL, Vianna LC. Altered cardiorespiratory regulation during exercise in patients with Parkinson's disease: A challenging non-motor feature. SAGE Open Med 2020; 8:2050312120921603. [PMID: 32435491 PMCID: PMC7222646 DOI: 10.1177/2050312120921603] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 04/03/2020] [Indexed: 01/27/2023] Open
Abstract
The incidence of Parkinson’s disease is increasing worldwide. The motor dysfunctions are the hallmark of the disease, but patients also experience non-motor impairments, and over 40% of the patients experience coexistent abnormalities, such as orthostatic hypotension. Exercise training has been suggested as a coping resource to alleviate Parkinson’s disease symptoms and delay disease progression. However, the body of knowledge is showing that the cardiovascular response to exercise in patients with Parkinson’s disease is altered. Adequate cardiovascular and hemodynamic adjustments to exercise are necessary to meet the metabolic demands of working skeletal muscle properly. Therefore, since Parkinson’s disease affects parasympathetic and sympathetic branches of the autonomic nervous system and the latter are crucial in ensuring these adjustments are adequately made, the understanding of these responses during exercise in this population is necessary. Several neural control mechanisms are responsible for the autonomic changes in the cardiovascular and hemodynamic systems seen during exercise. In this sense, the purpose of the present work is to review the current knowledge regarding the cardiovascular responses to dynamic and isometric/resistance exercise as well as the mechanisms by which the body maintains appropriate perfusion pressure to all organs during exercise in patients with Parkinson’s disease. Results from patients with Parkinson’s disease and animal models of Parkinson’s disease provide the reader with a well-rounded knowledge base. Through this, we will highlight what is known and not known about how the neural control of circulation is responding during exercise and the adaptations that occur when individuals exercise regularly.
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Affiliation(s)
- Jeann L Sabino-Carvalho
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
| | - Lauro C Vianna
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil.,Graduate Program in Medical Sciences, Faculty of Medicine, University of Brasília, Brasília, Brazil
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