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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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2
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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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3
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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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4
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Stens NA, Hisdal J, Bakke EF, Kaur N, Sharma A, Stranden E, Thijssen DHJ, Høiseth LØ. Factors mediating the pressor response to isometric muscle contraction: An experimental study in healthy volunteers during lower body negative pressure. PLoS One 2020; 15:e0243627. [PMID: 33296410 PMCID: PMC7725372 DOI: 10.1371/journal.pone.0243627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/24/2020] [Indexed: 12/20/2022] Open
Abstract
Whilst both cardiac output (CO) and total peripheral resistance (TPR) determine mean arterial blood pressure (MAP), their relative importance in the pressor response to isometric exercise remains unclear. This study aimed to elucidate the relative importance of these two different factors by examining pressor responses during cardiopulmonary unloading leading to step-wise reductions in CO. Hemodynamics were investigated in 11 healthy individuals before, during and after two-minute isometric exercise during lower body negative pressure (LBNP; -20mmHg and -40mmHg). The blood pressure response to isometric exercise was similar during normal and reduced preload, despite a step-wise reduction in CO during LBNP (-20mmHg and -40mmHg). During -20mmHg LBNP, the decreased stroke volume, and consequently CO, was counteracted by an increased TPR, while heart rate (HR) was unaffected. HR was increased during -40 mmHg LBNP, although insufficient to maintain CO; the drop in CO was perfectly compensated by an increased TPR to maintain MAP. Likewise, transient application of LBNP (-20mmHg and -40mmHg) resulted in a short transient drop in MAP, caused by a decrease in CO, which was compensated by an increase in TPR. This study suggests that, in case of reductions of CO, changes in TPR are primarily responsible for maintaining the pressor response during isometric exercise. This highlights the relative importance of TPR compared to CO in mediating the pressor response during isometric exercise.
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Affiliation(s)
- Niels A. Stens
- Department of Physiology, Research Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Section of Vascular Investigations, Oslo University Hospital, Oslo, Norway
| | - Jonny Hisdal
- Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Section of Vascular Investigations, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Espen F. Bakke
- Institute of Aviation Medicine, Norwegian Armed Forces Medical Service, Oslo, Norway
| | - Narinder Kaur
- Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Section of Vascular Investigations, Oslo University Hospital, Oslo, Norway
- Dermatology Center Telemark, Porsgrunn, Norway
| | - Archana Sharma
- Department of Endocrinology, Oslo University Hospital, Oslo, Norway
- Department of Anesthesiology, Oslo University Hospital, Oslo, Norway
| | - Einar Stranden
- Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Section of Vascular Investigations, Oslo University Hospital, Oslo, Norway
| | - Dick H. J. Thijssen
- Department of Physiology, Research Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Lars Øivind Høiseth
- Department of Anesthesiology, Oslo University Hospital, Oslo, Norway
- * E-mail:
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5
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Dillon GA, Lichter ZS, Alexander LM, Vianna LC, Wang J, Fadel PJ, Greaney JL. Reproducibility of the neurocardiovascular responses to common laboratory-based sympathoexcitatory stimuli in young adults. J Appl Physiol (1985) 2020; 129:1203-1213. [PMID: 32940559 DOI: 10.1152/japplphysiol.00210.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The magnitude of blood pressure (BP) and muscle sympathetic nerve activity (MSNA) responses to laboratory stressors is commonly used to compare neurocardiovascular responsiveness between groups and conditions. However, no studies have rigorously examined the reproducibility of BP and MSNA responsiveness. Here, we assess the within-visit reproducibility of BP (finger photoplethysmography) and MSNA (microneurography) responses to isometric handgrip (HG) and postexercise ischemia (PEI) in young healthy adults (n = 30). In a subset (n = 21), we also examined the between-visit reproducibility of responsiveness to HG, PEI, and the cold pressor test (CPT). Intraclass correlation coefficients (ICCs) were used as a primary reproducibility measure (e.g., ICC >0.75 is considered very good). Within a visit, the increase in mean arterial pressure during HG [ICC = 0.85 (0.69-0.93); P < 0.001] and PEI [ICC = 0.85 (0.69-0.93); P < 0.001] demonstrated very good reproducibility. Furthermore, the between-visit reproducibility of the pressor response to HG [ICC = 0.85 (0.62-0.94); P < 0.001], PEI [ICC = 0.84 (CI = 0.58-0.94); P < 0.001], and the CPT [ICC = 0.89 (0.72-0.95) P < 0.001]) were also very good. However, there was greater variability in both the within- [HG: ICC = 0.58 (-0.22-0.85), P = 0.001; PEI: ICC = 0.33 (-0.24-0.69), P = 0.042] and between-visit reproducibility of MSNA responsiveness [HG: ICC = 0.87 (0.53-0.96), P = 0.001; PEI: ICC = 0.24 (-0.62-0.78), P = 0.27; CPT: ICC = 0.77 (0.29-0.93), P = 0.007]. The magnitude of the BP response to several standard laboratory stimuli was very good, whereas the variability of the MSNA response to these perturbations was generally less consistent, particularly during PEI. These data provide novel insight for both study design and data interpretation when comparing neurocardiovascular responsiveness between different conditions, groups, or studies, as well as before and after interventions/treatments.NEW & NOTEWORTHY The magnitude of the increases in blood pressure and muscle sympathetic nerve activity in response to sympathoexcitatory stimuli such as static handgrip, postexercise ischemia, and the cold pressor test are commonly used to assess neurocardiovascular responsiveness. However, limited studies have comprehensively examined the reproducibility of these responses. We demonstrate that the reproducibility of the pressor response to these perturbations was very good within an individual, whereas the reproducibility of the MSNA response was less consistent.
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Affiliation(s)
- Gabrielle A Dillon
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - Zachary S Lichter
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - Lacy M Alexander
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - Lauro C Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
| | - Jing Wang
- College of Nursing, The University of Texas at Arlington, Arlington, Texas
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Jody L Greaney
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
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6
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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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7
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Limberg JK, Casey DP, Trinity JD, Nicholson WT, Wray DW, Tschakovsky ME, Green DJ, Hellsten Y, Fadel PJ, Joyner MJ, Padilla J. Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology. Am J Physiol Heart Circ Physiol 2019; 318:H301-H325. [PMID: 31886718 DOI: 10.1152/ajpheart.00649.2019] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,François M. Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | | | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia, Australia
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | | | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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8
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Multiannual, Intensive Strength-Endurance Training Modulates the Activity of the Cardiovascular and Autonomic Nervous System among Rowers of the International Level. BIOMED RESEARCH INTERNATIONAL 2019; 2019:3989304. [PMID: 31662977 PMCID: PMC6791253 DOI: 10.1155/2019/3989304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/24/2019] [Indexed: 11/17/2022]
Abstract
Introduction Professional athlete training is significantly different from recreational physical activity, and sustained, repetitive exposure to over-strenuous and intensive training may result in critical changes of most systems and organs in a sportsman's body. Aim The assessment of the influence of multiannual strength-endurance training on the autonomic nervous system (ANS) and cardiovascular system (CVS) among the rowers of Polish national team. Materials and Methods 20 rowers, aged 20–30, seniors of Polish national team were qualified into the study. The functional examination of ANS was conducted by means of Task Force® Monitor system. The assessed parameters included hemodynamic parameters, heart rate, and blood pressure variability and reflexes sensitivity of baroreceptors. In order to examine and compare the reaction of autonomic nervous system the subjects underwent a tilt test. Results In the study group, significantly higher levels of sBP (129.3 ± 12.2 vs 118.3 ± 8.4, p = 0.0030), SI (59.9 ± 8.8 vs 41.2 ± 6.8, p > 0.001), CI (3.2 ± 0.5 vs 2.4 ± 0.4, p > 0.001), and significantly lower levels of HR (54.2 ± 5.3 vs 60.1 ± 5.7, p = 0.0034) and TPRI (2333.3 ± 389.9 vs 2950.2 ± 604.2, p = 0.0012) compared to the control group, were found. After the tilt test the levels of HR (p = 0.0005) and TPRI (p = 0.0128) were significantly higher but SI (p > 0.001) and CI (p = 0.0006) were significantly lower in the study group compared to the control. Conclusions Multiannual strength-endurance training connected with rowing activities substantially modulates the activity of cardiovascular and autonomic nervous system, influences the volumetric workload of the heart and structural changes, and increases the sensitivity of reflexes of arterial baroreceptors.
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Campos MO, Mansur DE, Mattos JD, Paiva ACS, Videira RLR, Macefield VG, da Nóbrega ACL, Fernandes IA. Acid-sensing ion channels blockade attenuates pressor and sympathetic responses to skeletal muscle metaboreflex activation in humans. J Appl Physiol (1985) 2019; 127:1491-1501. [PMID: 31545154 DOI: 10.1152/japplphysiol.00401.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In animals, the blockade of acid-sensing ion channels (ASICs), cation pore-forming membrane proteins located in the free nerve endings of group IV afferent fibers, attenuates increases in arterial pressure (AP) and sympathetic nerve activity (SNA) during muscle contraction. Therefore, ASICs play a role in mediating the metabolic component (skeletal muscle metaboreflex) of the exercise pressor reflex in animal models. Here we tested the hypothesis that ASICs also play a role in evoking the skeletal muscle metaboreflex in humans, quantifying beat-by-beat mean AP (MAP; finger photoplethysmography) and muscle SNA (MSNA; microneurography) in 11 men at rest and during static handgrip exercise (SHG; 35% of the maximal voluntary contraction) and postexercise muscle ischemia (PEMI) before (B) and after (A) local venous infusion of either saline or amiloride (AM), an ASIC antagonist, via the Bier block technique. MAP (BAM +30 ± 6 vs. AAM +25 ± 7 mmHg, P = 0.001) and MSNA (BAM +14 ± 9 vs. AAM +10 ± 6 bursts/min, P = 0.004) responses to SHG were attenuated under ASIC blockade. Amiloride also attenuated the PEMI-induced increases in MAP (BAM +25 ± 6 vs. AAM +16 ± 6 mmHg, P = 0.0001) and MSNA (BAM +16 ± 9 vs. AAM +8 ± 8 bursts/min, P = 0.0001). MAP and MSNA responses to SHG and PEMI were similar before and after saline infusion. We conclude that ASICs play a role in evoking pressor and sympathetic responses to SHG and the isolated activation of the skeletal muscle metaboreflex in humans. NEW & NOTEWORTHY We showed that regional blockade of the acid-sensing ion channels (ASICs), induced by venous infusion of the antagonist amiloride via the Bier block anesthetic technique, attenuated increases in arterial pressure and muscle sympathetic nerve activity during both static handgrip exercise and postexercise muscle ischemia. These findings indicate that ASICs contribute to both pressor and sympathetic responses to the activation of the skeletal muscle metaboreflex in humans.
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Affiliation(s)
- Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Adrielle C S Paiva
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | | | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
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10
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Doherty CJ, King TJ, Incognito AV, Lee JB, Shepherd AD, Cacoilo JA, Slysz JT, Burr JF, Millar PJ. Effects of dynamic arm and leg exercise on muscle sympathetic nerve activity and vascular conductance in the inactive leg. J Appl Physiol (1985) 2019; 127:464-472. [PMID: 31246555 DOI: 10.1152/japplphysiol.00997.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The influence of muscle sympathetic nerve activity (MSNA) responses on local vascular conductance during exercise are not well established. Variations in exercise mode and active muscle mass can produce divergent MSNA responses. Therefore, we sought to examine the effects of small- versus large-muscle mass dynamic exercise on vascular conductance and MSNA responses in the inactive limb. Thirty-five participants completed two study visits in a randomized order. During visit 1, superficial femoral artery (SFA) blood flow (Doppler ultrasound) was assessed at rest and during steady-state rhythmic handgrip (RHG; 1:1 duty cycle, 40% maximal voluntary contraction), one-leg cycling (17 ± 3% peak power output), and concurrent exercise at the same intensities. During visit 2, MSNA (contralateral fibular nerve microneurography) was acquired successfully in 12/35 participants during the same exercise modes. SFA blood flow increased during RHG (P < 0.0001) and concurrent exercise (P = 0.03) but not cycling (P = 0.91). SFA vascular conductance was unchanged during RHG (P = 0.88) but reduced similarly during concurrent and cycling exercise (both P < 0.003). RHG increased MSNA burst frequency (P = 0.04) without altering burst amplitude (P = 0.69) or total MSNA (P = 0.26). In contrast, cycling and concurrent exercise had no effects on MSNA burst frequency (both P ≥ 0.10) but increased burst amplitude (both P ≤ 0.001) and total MSNA (both P ≤ 0.007). Across all exercise modes, the changes in MSNA burst amplitude and SFA vascular conductance were correlated negatively (r = -0.43, P = 0.02). In summary, the functional vascular consequences of alterations in sympathetic outflow to skeletal muscle are most closely associated with changes in MSNA burst amplitude, but not frequency, during low-intensity dynamic exercise.NEW & NOTEWORTHY Low-intensity small- versus large-muscle mass exercise can elicit divergent effects on muscle sympathetic nerve activity (MSNA). We examined the relationships between changes in MSNA (burst frequency and amplitude) and superficial femoral artery (SFA) vascular conductance during rhythmic handgrip, one-leg cycling, and concurrent exercise in the inactive leg. Only changes in MSNA burst amplitude were inversely associated with SFA vascular conductance responses. This result highlights the functional importance of measuring MSNA burst amplitude during exercise.
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Affiliation(s)
- Connor J Doherty
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Trevor J King
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Anthony V Incognito
- 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
| | - Andrew D Shepherd
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Joseph A Cacoilo
- Department of Kinesiology, University of Guelph-Humber, Toronto, Ontario, Canada
| | - Joshua T Slysz
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jamie F Burr
- 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 General Hospital, Toronto, Ontario, Canada
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11
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Samora M, Incognito AV, Vianna LC. Sex differences in blood pressure regulation during ischemic isometric exercise: the role of the β-adrenergic receptors. J Appl Physiol (1985) 2019; 127:408-414. [PMID: 31219771 DOI: 10.1152/japplphysiol.00270.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We sought to investigate whether the β-adrenergic receptors play a pivotal role in sex-related differences in arterial blood pressure (BP) regulation during isometric exercise. Sixteen volunteers (8 women) performed 2 min of ischemic isometric handgrip exercise (IHE) and 2 min of postexercise circulatory occlusion (PECO). Heart rate (HR) and beat-to-beat arterial BP were continuously measured. Beat-to-beat estimates of stroke volume (ModelFlow) were obtained and matched with HR to calculate cardiac output (Q̇) and total peripheral resistance (TPR). Two trials were randomly conducted between placebo and nonselective β-adrenergic blockade (40 mg propranolol). Under the placebo condition, the magnitude of the BP response in IHE was lower in women compared with men. During PECO, the BP remained elevated and the sex differences persisted. The β-blockade attenuated the BP response during IHE in men (∆57 ± 4 vs. ∆45 ± 7 mmHg, P = 0.025) due to a reduction in Q̇ (∆3.7 ± 0.5 vs. ∆1.8 ± 0.2 L/min, P = 0.012) while TPR was not affected. In women, however, the BP response during IHE was unchanged (∆27 ± 3 vs. ∆28 ± 3 mmHg, P = 0.889), despite attenuated Q̇ (∆2.7 ± 0.4 vs. ∆1.3 ± 0.2 L/min, P = 0.012). These responses were mediated by a robust increase in TPR under β-blockade (∆-0.2 ± 0.4 vs. ∆2.2 ± 0.7 mmHg·L-1·min, P = 0.012). These findings demonstrate that the sex differences in arterial BP regulation during ischemic IHE are mediated by β-adrenergic receptors.NEW & NOTEWORTHY We found that the blood pressure response during isometric exercise in women is mediated by increases in cardiac output, whereas in men it is mediated by increases in both cardiac output and total peripheral resistance. In addition, women showed a robust increase in total peripheral resistance under β-blockade during isometric exercise and muscle metaboreflex activation. These findings demonstrate that sex differences in blood pressure regulation during isometric exercise are mediated by β-adrenergic receptors.
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Affiliation(s)
- Milena Samora
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasilia, Distrito Federal, Brazil
| | - Anthony V Incognito
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasilia, Distrito Federal, Brazil.,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, Brasilia, Distrito Federal, Brazil
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Joshi H, Edgell H. Sex differences in the ventilatory and cardiovascular response to supine and tilted metaboreflex activation. Physiol Rep 2019; 7:e14041. [PMID: 30916469 PMCID: PMC6436143 DOI: 10.14814/phy2.14041] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 12/26/2022] Open
Abstract
Women have attenuated exercise pressor responses compared to men; however, their cerebrovascular and ventilatory responses have not been previously measured. Furthermore, recent evidence has shown that posture change can influence the response of the metaboreflex but this has only been tested in men. Young and healthy men (n = 14; age: 21 ± 2) and women (n = 11; age: 19 ± 1) underwent 40% MVC static handgrip exercise (HG) for 2 min followed by 3 min of post-exercise circulatory occlusion (PECO) in the supine and 70° tilted postures. In supine position during HG and PECO only men had an increase in ventilation (Men: Baseline: 12.5 ± 1.7 L/min, HG: 18.6 ± 5.3 L/min, PECO: 17.7 ± 10.3 L/min; Women: Baseline: 12.0 ± 1.5 L/min, HG: 12.4 ± 1.2 L/min, PECO: 11.5 ± 1.3 L/min; Sex × Time interaction P = 0.037). In supine position during HG and PECO men and women had similar reductions in cerebrovascular conductance (Men: Baseline: 0.79 ± 0.13 cm/sec/mmHg, HG: 0.68 ± 0.18 cm/sec/mmHg, PECO: 0.61 ± 0.19 cm/s/mmHg; Women: Baseline: 0.87 ± 0.13 cm/sec/mmHg, HG: 0.83 ± 0.14 cm/sec/mmHg, PECO: 0.75 ± 0.17 cm/sec/mmHg; P < 0.015 HG/PECO vs. baseline). When comparing the response to PECO in the supine versus upright postures there was a significant attenuation in the increase in mean arterial pressure in both men and women (Supine posture: Men: +23.3 ± 14.5 mmHg, Women: +12.0 ± 7.3 mmHg; Upright posture: Men: +15.7 ± 14.1 mmHg, Women: +7.7 ± 6.7 mmHg; Main effect of sex P = 0.042, Main effect of posture P < 0.001). Our results indicate sexually dimorphic ventilatory responses to HG and PECO which could be due to different interactions of the metaboreflex and chemoreflex. We have also shown evidence of attenuated metaboreflex function in the upright posture in both men and women.
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Affiliation(s)
- Hitesh Joshi
- School of Kinesiology and Health SciencesYork UniversityTorontoOntarioCanada
| | - Heather Edgell
- School of Kinesiology and Health SciencesYork UniversityTorontoOntarioCanada
- Muscle Health Research CentreYork UniversityTorontoOntarioCanada
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Teixeira AL, Samora M, Vianna LC. Muscle metaboreflex activation via postexercise ischemia as a tool for teaching cardiovascular physiology for undergraduate students. ADVANCES IN PHYSIOLOGY EDUCATION 2019; 43:34-41. [PMID: 30540204 DOI: 10.1152/advan.00174.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The cardiovascular responses to exercise are mediated by several interactive neural mechanisms, including central command, arterial baroreflex, and skeletal muscle mechano- and metaboreflex. In humans, muscle metaboreflex activation can be isolated via postexercise ischemia (PEI), which increases sympathetic nerve activity and partially maintains the exercise-induced increase in arterial blood pressure. Here, we describe a practical laboratory class using PEI as a simple and useful technique to teach cardiovascular physiology. In an undergraduate exercise physiology class ( n = 47), a traditional 4-h lecture was conducted discussing the neural control mechanisms of cardiovascular regulation during exercise. Thereafter, eight students (4 men and 4 women) were selected to participate as a volunteer of a practical laboratory class. Each participant performed 90 s of isometric handgrip exercise at 40% of maximal voluntary contraction, followed by 3 min of PEI. Arterial blood pressure and heart rate were measured by digital monitors at rest and during isometric handgrip, PEI, and recovery. In addition, blood samples were collected from the tip of the exercising finger for blood lactate analyses. After the laboratory class, a survey was given to determine the perceptions of the students. The findings demonstrate that this laboratory class has proved to be highly popular with students, who self-reported a significant improvement in their understanding of several aspects of cardiovascular regulation during exercise.
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Affiliation(s)
- André L Teixeira
- NeuroV̇ASQ̇, Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasília , Brazil
| | - Milena Samora
- 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
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Vianna LC, Fernandes IA, Barbosa TC, Teixeira AL, Nóbrega ACL. Capsaicin-based analgesic balm attenuates the skeletal muscle metaboreflex in healthy humans. J Appl Physiol (1985) 2018; 125:362-368. [PMID: 29698108 DOI: 10.1152/japplphysiol.00038.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The exercise pressor reflex (EPR) is comprised of group III and IV skeletal muscle afferents and is one of the principal mediators of the cardiovascular response to exercise. In animals, capsaicin-based analgesic balm (CAP) attenuates the pressor response to muscle contraction, indicating the transient receptor potential vanilloid 1 (TRPv1) receptor (localized on the group IV afferent neuron) as an important mediator of the EPR. However, whether these findings can be extrapolated to humans remains unknown. Here, we tested the hypothesis that CAP would attenuate blood pressure (BP) and muscle sympathetic nerve activity (MSNA) responses to isolated muscle metaboreflex activation in healthy men. MSNA (microneurography) and beat-to-beat heart hate (HR, by electrocardiography), and BP (finger photoplethysmography) were continuously measured in eight healthy males (23 ± 5 yr) at rest, during isometric handgrip exercise, and during postexercise ischemia (PEI). Trials were performed before and 30 and 60 min after the topical application of CAP (0.1%, CAPZASIN-HP) over the volar forearm of the subject's exercising arm. Isometric exercise evoked increases in mean BP (∆32 ± 4 mmHg) and MSNA (∆26 ± 5 bursts/min; ∆19 ± 5 bursts/100 heart beats). The increases in BP during handgrip were not affected by CAP, but the increase in MSNA was lower after 60 min of CAP application. During PEI, the increases in BP and MSNA were all significantly less than those before CAP (all P < 0.05). In conclusion, CAP attenuated BP and sympathetic responses evoked by PEI in humans. These data provide evidence that transient receptor potential vanilloid 1 receptors potentially contribute to the EPR in humans, via its metabolic component. NEW & NOTEWORTHY We found that topical application of capsaicin-based analgesic balm attenuates arterial blood pressure and muscle sympathetic nerve activity during isolated muscle metaboreflex activation following isometric handgrip exercise in healthy humans. These findings suggest that the transient receptor potential vanilloid 1 may contribute to the exercise pressor reflex in humans via its metabolic component.
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Affiliation(s)
- Lauro C Vianna
- NeuroVASQ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasilia, Federal District , Brazil
| | - Igor A Fernandes
- NeuroVASQ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasilia, Federal District , Brazil.,Department of Physiology and Pharmacology, Fluminense Federal University , Niterói, Rio de Janeiro , Brazil
| | - Thales C Barbosa
- Department of Kinesiology, University of Texas at Arlington , Arlington, Texas
| | - André L Teixeira
- NeuroVASQ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasilia, Federal District , Brazil
| | - Antonio C L Nóbrega
- Department of Physiology and Pharmacology, Fluminense Federal University , Niterói, Rio de Janeiro , Brazil
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