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Matus LN, Flessland OD, Mueller PJ. Sex-dependent development of enhanced sympathoexcitation in sedentary versus physically active rats. J Physiol 2021; 599:4101-4116. [PMID: 34258769 DOI: 10.1113/jp281757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 07/07/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The rostral ventrolateral medulla (RVLM) may contribute to sex-based differences in cardiovascular disease (CVD) based on overactivation of the sympathetic nervous system observed in sedentary male rats; however, the added influence of the reproductive cycle in females is currently unknown. To our knowledge this is the first study to demonstrate greater increases in sympathetic nerve activity in response to direct activation of the RVLM in female versus male rats prior to the onset of the reproductive cycle, which persisted after the onset of the reproductive cycle. Lower resting blood pressures in females also suggest peripheral adaptations contribute to sex-based differences in CVD. Sedentary versus physically active conditions appear to promote higher resting sympathetic outflow independent of age and sex. Our results demonstrate the importance of examining sedentary conditions in the context of sex differences and the reproductive cycle in contributing to sympathetic overactivity associated with cardiovascular disease. ABSTRACT Female reproductive hormones are considered cardioprotective based on higher risks of cardiovascular disease (CVD) in post- versus pre-menopausal women. Similarly, based on epidemiological studies, a sedentary lifestyle is also a major risk factor for CVD. The mechanisms by which sedentary conditions contribute to CVD, and their influences in the presence and absence of female reproductive hormones are unknown. We hypothesized that sexually immature male and female rats would have similar centrally mediated regulation of blood pressure, but upon sexual maturation, female rats would have lower resting blood pressure and centrally-mediated sympathoexcitation compared to age-matched males. We also predicted resting sympathetic activity would increase upon exposure to sedentary versus active conditions (voluntary wheel running) in males but not in females. We recorded splanchnic sympathetic nerve activity (SSNA) and blood pressure in 4-, 8- and 16-week-old male and female rats under Inactin anaesthesia before and during microinjections of glutamate (1-100 mM) into the rostral ventrolateral medulla (RVLM). Four-week-old female rats had lower resting blood pressure and greater sympathoexcitation following activation of the RVLM, as did 8- and 16-week-old female rats, independent of age or activity condition. Sedentary animals had higher baseline SSNA compared to active animals, independent of sex or age. Our results reveal a complex influence of the interactions between the female reproductive cycle and sedentary conditions. They also demonstrate the importance of examining sedentary conditions in the context of sex- and female reproductive cycle-dependent incidences of cardiovascular disease.
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Affiliation(s)
- Lyndsey N Matus
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI, 48201, USA
| | - Olivia D Flessland
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI, 48201, USA
| | - Patrick J Mueller
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI, 48201, USA
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Covassin N, Bukartyk J, Singh P, Calvin AD, St Louis EK, Somers VK. Effects of Experimental Sleep Restriction on Ambulatory and Sleep Blood Pressure in Healthy Young Adults: A Randomized Crossover Study. Hypertension 2021; 78:859-870. [PMID: 34247512 DOI: 10.1161/hypertensionaha.121.17622] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Naima Covassin
- Department of Cardiovascular Medicine (N.C., J.B., P.S., V.K.S.), Mayo Clinic, Rochester, MN
| | - Jan Bukartyk
- Department of Cardiovascular Medicine (N.C., J.B., P.S., V.K.S.), Mayo Clinic, Rochester, MN
| | - Prachi Singh
- Department of Cardiovascular Medicine (N.C., J.B., P.S., V.K.S.), Mayo Clinic, Rochester, MN.,Pennington Biomedical Research Center, Baton Rouge, LA (P.S.)
| | - Andrew D Calvin
- Department of Cardiovascular Medicine, Mayo Clinic Health System, Eau Claire, WI (A.D.C.)
| | - Erik K St Louis
- Center for Sleep Medicine, Department of Neurology (E.K.S.L.), Mayo Clinic, Rochester, MN.,Division of Pulmonary and Critical Care Medicine, Department of Medicine (E.K.S.L.), Mayo Clinic, Rochester, MN
| | - Virend K Somers
- Department of Cardiovascular Medicine (N.C., J.B., P.S., V.K.S.), Mayo Clinic, Rochester, MN
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Katayama K, Dominelli PB, Foster GE, Kipp S, Leahy MG, Ishida K, Sheel AW. Respiratory modulation of sympathetic vasomotor outflow during graded leg cycling. J Appl Physiol (1985) 2021; 131:858-867. [PMID: 34197231 DOI: 10.1152/japplphysiol.00118.2021] [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: 11/22/2022] Open
Abstract
Respiratory modulation of sympathetic vasomotor outflow to skeletal muscles (muscle sympathetic nerve activity; MSNA) occurs in resting humans. Specifically, MSNA is highest at end-expiration and lowest at end-inspiration during quiet, resting breathing. We tested the hypothesis that within-breath modulation of MSNA would be amplified during graded leg cycling. Thirteen (n = 3 females) healthy young (age: 25.2 ± 4.7 yr) individuals completed all testing. MSNA (right median nerve) was measured at rest (baseline) and during semirecumbent cycle exercise at 40%, 60%, and 80% of maximal workload (Wmax). MSNA burst frequency (BF) was 20.0 ± 4.0 bursts/min at baseline and was not different during exercise at 40%Wmax (21.3 ± 3.7 bursts/min; P = 0.292). Thereafter, MSNA BF increased significantly compared with baseline (60%Wmax: 31.6 ± 5.8 bursts/min; P < 0.001, 80%Wmax: 44.7 ± 5.3 bursts/min; P < 0.001). At baseline and all exercise intensities, MSNA BF was lowest at end-inspiration and greatest at mid-to-end expiration. The within-breath change in MSNA BF (ΔMSNA BF; end-expiration minus end-inspiration) gradually increased from baseline to 60%Wmax leg cycling, but no further increase appeared at 80%Wmax exercise. Our results indicate that within-breath modulation of MSNA is amplified from baseline to moderate intensity during dynamic exercise in young healthy individuals, and that no further potentiation occurs at higher exercise intensities. Our findings provide an important extension of our understanding of respiratory influences on sympathetic vasomotor control.NEW & NOTEWORTHY Within-breath modulation of sympathetic vasomotor outflow to skeletal muscle (muscle sympathetic nerve activity; MSNA) occurs in spontaneously breathing humans at rest. It is unknown if respiratory modulation persists during dynamic whole body exercise. We found that MSNA burst frequency was lowest at end-inspiration and highest at mid-to-end expiration during rest and graded leg cycling. Respiratory modulation of sympathetic vasomotor outflow remains intact and is amplified during dynamic whole body exercise.
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Affiliation(s)
- Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Paolo B Dominelli
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, 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
| | - Shalaya Kipp
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael G Leahy
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Andrew William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
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54
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Assadpour E, Ivry I, Wasef S, Adeyinka B, Murray KR, Edgell H. Oral contraceptives and menstrual cycle influence autonomic reflex function. Physiol Rep 2021; 8:e14550. [PMID: 32889781 PMCID: PMC7507440 DOI: 10.14814/phy2.14550] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 12/31/2022] Open
Abstract
Progesterone and its analogues are known to influence ventilation. Therefore, the purpose of this study was to investigate the role of endogenous and pharmaceutical female sex hormones in ventilatory control during the activation of the metaboreflex, mechanoreflex, and CO2 chemoreflex. Women aged 18–30 taking (n = 14) or not taking (n = 12) oral contraceptives (OC and NOC, respectively) were tested in the low hormone (LH) and high hormone (HH) conditions corresponding to the early follicular and mid‐luteal phases (NOC) or placebo and high‐dose pills (OC). Women underwent three randomized trials: (a) 3 min of passive leg movement (PLM), (b) 2 min of 40% maximal voluntary handgrip exercise followed by 2 min of post‐exercise circulatory occlusion (PECO), and (c) 5 min of breathing 5% CO2. We primarily measured hemodynamics and ventilation. During PLM, the OC group had a smaller pressor response (p = .012). During PECO, the OC group similarly exhibited a smaller pressor response (p = .043) and also exhibited a greater ventilatory response (p = .024). Lastly, in response to breathing 5% CO2, women in the HH phase had a greater ventilatory response (p = .022). We found that OC use attenuates the pressor response to both the metaboreflex and mechanoreflex while increasing the ventilatory response to metaboreflex activation. We also found evidence of an enhanced CO2 chemoreflex in the HH phase. We hypothesize that OC effects are from the chronic upregulation of pulmonary and vascular β‐adrenergic receptors. We further suggest that the increased cyclic progesterone in the HH phase enhances the chemoreflex.
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Affiliation(s)
- Elnaz Assadpour
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Ilana Ivry
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Sara Wasef
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Baithat Adeyinka
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Kevin R Murray
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Heather Edgell
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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55
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Tymko MM, Berthelsen LF, Skow RJ, Steele AR, Fraser GM, Steinback CD. Assessing static and dynamic sympathetic transduction using microneurography. J Appl Physiol (1985) 2021; 130:1626-1634. [PMID: 33792401 DOI: 10.1152/japplphysiol.00032.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The relationship between sympathetic nerve activity and the vasculature has been of great interest due to its potential role in various cardiovascular-related diseases. This relationship, termed "sympathetic transduction," has been quantified using several different laboratory and analytical techniques. The most common method is to assess the association between relative changes in muscle sympathetic nerve activity, measured via microneurography, and physiological outcomes (e.g., blood pressure, total peripheral resistance, blood flow, etc.) in response to a sympathetic stressor (e.g., exercise, cold stress, orthostatic stress). This approach, however, comes with its own caveats. For instance, elevations in blood pressure and heart rate during a sympathetic stressor can have an independent impact on muscle sympathetic nerve activity. Another assessment of sympathetic transduction was developed by Wallin and Nerhed in 1982, where alterations in blood pressure and heart rate were assessed immediately following bursts of muscle sympathetic nerve activity at rest. This approach has since been characterized and further innovated by others, including the breakdown of consecutive burst sequences (e.g., singlet, doublet, triplet, and quadruplet), and burst height (quartile analysis) on specific vascular outcomes (e.g., blood pressure, blood flow, vascular resistance). The purpose of this review is to provide an overview of the literature that has assessed sympathetic transduction using microneurography and various sympathetic stressors (static sympathetic transduction) and using the same or similar approach established by Wallin and Nerhed at rest (dynamic neurovascular transduction). Herein, we discuss the overlapping literature between these two methodologies and highlight the key physiological questions that remain.
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Affiliation(s)
- Michael M Tymko
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Lindsey F Berthelsen
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Rachel J Skow
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew R Steele
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Graham M Fraser
- The Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Craig D Steinback
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
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56
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Giersch GEW, Charkoudian N, Pereira T, Edgell H, Freeberg KA, Craighead DH, Neill M, Allison EY, Zapcic AK, Smith KJ, Bock JM, Casey DP, Shenouda N, Ranadive SM, Tremblay JC, Williams AM, Simpson LL, Meah VL, Ruediger SL, Bailey TG, Pereira HM, Lei TH, Perry B, Mündel T, Freemas JA, Worley ML, Baranauskas MN, Carter SJ, Johnson BD, Schlader ZJ, Bates LC, Stoner L, Zieff G, Poles J, Adams N, Meyer ML, Hanson ED, Greenlund IM, Bigalke JA, Carter JR, Kerr ZY, Stanford K, Pomeroy A, Boggess K, de Souza HLR, Meireles A, Arriel RA, Leite LHR, Marocolo M, Chapman CL, Atencio JK, Kaiser BW, Comrada LN, Halliwill JR, Minson CT, Williams JS, Dunford EC, MacDonald MJ, Santisteban KJ, Larson EA, Reed E, Needham KW, Gibson BM, Gillen J, Barbosa TC, Cardoso LLY, Gliemann L, Tamariz-Ellemann A, Hellsten Y, DuBos LE, Babcock MC, Moreau KL, Wickham KA, Vagula M, Moir ME, Klassen SA, Rodrigues A. Commentaries on Point:Counterpoint: Investigators should/should not control for menstrual cycle phase when performing studies of vascular control. J Appl Physiol (1985) 2021; 129:1122-1135. [PMID: 33197376 DOI: 10.1152/japplphysiol.00809.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- Gabrielle E W Giersch
- Thermal and Mountain Medicine Division, United States Army Research Institute for Environmental Medicine, Natick, Massachusetts,Oak Ridge Institute for Science and Education, Oak Ridge, Tennnessee
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, United States Army Research Institute for Environmental Medicine, Natick, Massachusetts
| | - T Pereira
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada
| | - H Edgell
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada
| | - Kaitlin A Freeberg
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
| | - Daniel H Craighead
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado
| | - Matthew Neill
- Department of Kinesiology, Lakehead University, Thunder Bay, Ontario, Canada
| | - Elric Y Allison
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Andrea K Zapcic
- Department of Kinesiology, Lakehead University, Thunder Bay, Ontario, Canada
| | - Kurt J Smith
- Integrative Physiology Lab, Department of Kinesiology and Nutrition, University of Chicago, Chicago, Illinois
| | - Joshua M Bock
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa,Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa,Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Ninette Shenouda
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware
| | - Sushant M Ranadive
- Department of Kinesiology, University of Maryland, College Park, Maryland
| | - Joshua C Tremblay
- Centre for Heart, Lung and Vascular Health, University of British Columbia–Okanagan, Kelowna, British Columbia, Canada
| | - Alexandra M Williams
- Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada
| | - Lydia L Simpson
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom
| | - Victoria L Meah
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Stefanie L Ruediger
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre of Research on Exercise, Physical Activity and Health, The University of Queensland, Australia
| | - Tom G Bailey
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre of Research on Exercise, Physical Activity and Health, The University of Queensland, Australia,School of Nursing, Midwifery and Social Work, The University of Queensland, Australia
| | - Hugo M Pereira
- Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma
| | - Tze-Huan Lei
- College of Physical Education, Hubei Normal University, Huangshi, China,Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan
| | - Blake Perry
- School of Health Sciences, Massey University, Wellington, New Zealand
| | - Toby Mündel
- School of Sport Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Jessica A Freemas
- H.H. Morris Human Performance Laboratories, Dept. of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Morgan L Worley
- H.H. Morris Human Performance Laboratories, Dept. of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Marissa N Baranauskas
- H.H. Morris Human Performance Laboratories, Dept. of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Stephen J Carter
- H.H. Morris Human Performance Laboratories, Dept. of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Blair D Johnson
- H.H. Morris Human Performance Laboratories, Dept. of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Zachary J Schlader
- H.H. Morris Human Performance Laboratories, Dept. of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Lauren C Bates
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Lee Stoner
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Gabriel Zieff
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jillian Poles
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Nathan Adams
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Michelle L Meyer
- Department of Emergency Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Erik D Hanson
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Ian M Greenlund
- Department of Health and Human Development, Montana State University, Bozeman, Montana,Department of Psychology, Montana State University, Bozeman, Montana
| | - Jeremy A Bigalke
- Department of Health and Human Development, Montana State University, Bozeman, Montana,Department of Psychology, Montana State University, Bozeman, Montana
| | - Jason R Carter
- Department of Health and Human Development, Montana State University, Bozeman, Montana,Department of Psychology, Montana State University, Bozeman, Montana
| | - Zachary Y Kerr
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kathleen Stanford
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Alex Pomeroy
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kim Boggess
- Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Hiago L R de Souza
- Physiology and Human Performance Research Group, Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Anderson Meireles
- Physiology and Human Performance Research Group, Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Rhai A Arriel
- Physiology and Human Performance Research Group, Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Laura H R Leite
- Physiology and Human Performance Research Group, Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Moacir Marocolo
- Physiology and Human Performance Research Group, Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | | | - Jessica K Atencio
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Brendan W Kaiser
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Lindan N Comrada
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - John R Halliwill
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | | | - Jennifer S Williams
- Vascular Dynamics Lab, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Emily C Dunford
- Vascular Dynamics Lab, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Maureen J MacDonald
- Vascular Dynamics Lab, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | | | - Emily A Larson
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Emma Reed
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Karen W Needham
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Brandon M Gibson
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Jenna Gillen
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Canada
| | - Thales C Barbosa
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Licy L Yanes Cardoso
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Lasse Gliemann
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | | | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Lyndsey E DuBos
- Division of Geriatric Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Matthew C Babcock
- Division of Geriatric Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Kerrie L Moreau
- Division of Geriatric Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado,Veterans Affairs Eastern Colorado Geriatric Research, Educational and Clinical Center, Denver, Colorado
| | - Kate A Wickham
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | | | - M Erin Moir
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada
| | | | - Alex Rodrigues
- Physiology and Human Performance Research Group, Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
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DeLucia CM, DeBonis DR, Schwyhart SM, Bailey EF. Acute cardiovascular responses to a single bout of high intensity inspiratory muscle strength training in healthy young adults. J Appl Physiol (1985) 2021; 130:1114-1121. [PMID: 33600284 DOI: 10.1152/japplphysiol.01015.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
High intensity, low volume inspiratory muscle strength training (IMST) has favorable effects on casual systolic blood pressure and systemic vascular resistance. However, the acute effects of IMST on heart rate (HR), blood pressure (BP), and sympathetic regulation of vascular resistance and the trajectory of post exercise recovery are not known. We recruited 14 young adults (7 women/7 men, age: 22 ± 2 years) to perform a single bout of high intensity IMST (inspiratory resistance set at 75% of maximal inspiratory pressure) importantly, female and male subjects were matched in regard to the target inspiratory pressure and target inspiratory muscle work per breath. We recorded HR, beat-to-beat changes in BP and postganglionic, muscle sympathetic nerve activities (MSNA) continuously throughout baseline, a single bout of IMST (comprising five sets of 6 inspiratory efforts) and in recovery. We show that one bout of IMST does not effect a change in BP, however, it effects a significant increase in HR (68.4 ± 11.7 beats/min versus 85.4 ± 13.6 beats/min; P < 0.001) and a significant decline in MSNA (6.8 ± 1.1 bursts/15 s bin; P < 0.001 versus 3.6 ± 0.6 bursts/15 s bin) relative to baseline. Remarkably, among men MSNA rebounded to baseline levels within the first minute of recovery, however, in women, MSNA suppression persisted for 5 min. We show that in healthy young adults, high intensity, low volume respiratory training results in the acute suppression of MSNA. Importantly, MSNA suppression is of greater magnitude and longer duration in women than in men.NEW & NOTEWORTHY Previous studies show 6 weeks of high intensity, low volume inspiratory muscle strength training (IMST) lowers blood pressure (BP) and systemic vascular resistance in young adults. However, the acute response to IMST is unknown. We characterized BP, heart rate, and sympathetic nervous activity (SNA) in healthy young adults at baseline, during IMST, and in recovery. There was no acute effect of IMST on BP, however, there was significant IMST-related suppression of SNA that was of greater magnitude in women than men.
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Affiliation(s)
- Claire M DeLucia
- Department of Physiology University of Arizona College of Medicine, Tucson, Arizona
| | - Dean R DeBonis
- Department of Physiology University of Arizona College of Medicine, Tucson, Arizona
| | - Sarah M Schwyhart
- Department of Physiology University of Arizona College of Medicine, Tucson, Arizona
| | - E Fiona Bailey
- Department of Physiology University of Arizona College of Medicine, Tucson, Arizona
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Convertino VA, Koons NJ, Suresh MR. Physiology of Human Hemorrhage and Compensation. Compr Physiol 2021; 11:1531-1574. [PMID: 33577122 DOI: 10.1002/cphy.c200016] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hemorrhage is a leading cause of death following traumatic injuries in the United States. Much of the previous work in assessing the physiology and pathophysiology underlying blood loss has focused on descriptive measures of hemodynamic responses such as blood pressure, cardiac output, stroke volume, heart rate, and vascular resistance as indicators of changes in organ perfusion. More recent work has shifted the focus toward understanding mechanisms of compensation for reduced systemic delivery and cellular utilization of oxygen as a more comprehensive approach to understanding the complex physiologic changes that occur following and during blood loss. In this article, we begin with applying dimensional analysis for comparison of animal models, and progress to descriptions of various physiological consequences of hemorrhage. We then introduce the complementary side of compensation by detailing the complexity and integration of various compensatory mechanisms that are activated from the initiation of hemorrhage and serve to maintain adequate vital organ perfusion and hemodynamic stability in the scenario of reduced systemic delivery of oxygen until the onset of hemodynamic decompensation. New data are introduced that challenge legacy concepts related to mechanisms that underlie baroreflex functions and provide novel insights into the measurement of the integrated response of compensation to central hypovolemia known as the compensatory reserve. The impact of demographic and environmental factors on tolerance to hemorrhage is also reviewed. Finally, we describe how understanding the physiology of compensation can be translated to applications for early assessment of the clinical status and accurate triage of hypovolemic and hypotensive patients. © 2021 American Physiological Society. Compr Physiol 11:1531-1574, 2021.
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Affiliation(s)
- Victor A Convertino
- Battlefield Healthy & Trauma Center for Human Integrative Physiology, United States Army Institute of Surgical Research, JBSA San Antonio, Texas, USA
| | - Natalie J Koons
- Battlefield Healthy & Trauma Center for Human Integrative Physiology, United States Army Institute of Surgical Research, JBSA San Antonio, Texas, USA
| | - Mithun R Suresh
- Battlefield Healthy & Trauma Center for Human Integrative Physiology, United States Army Institute of Surgical Research, JBSA San Antonio, Texas, USA
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Holwerda SW, Carter JR, Yang H, Wang J, Pierce GL, Fadel PJ. CORP: Standardizing methodology for assessing spontaneous baroreflex control of muscle sympathetic nerve activity in humans. Am J Physiol Heart Circ Physiol 2021; 320:H762-H771. [PMID: 33275522 PMCID: PMC8082800 DOI: 10.1152/ajpheart.00704.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/28/2022]
Abstract
The use of spontaneous bursts of muscle sympathetic nerve activity (MSNA) to assess arterial baroreflex control of sympathetic nerve activity has seen increased utility in studies of both health and disease. However, methods used for analyzing spontaneous MSNA baroreflex sensitivity are highly variable across published studies. Therefore, we sought to comprehensively examine methods of producing linear regression slopes to quantify spontaneous MSNA baroreflex sensitivity in a large cohort of subjects (n = 150) to support a standardized procedure for analysis that would allow for consistent and comparable results across laboratories. The primary results demonstrated that 1) consistency of linear regression slopes was considerably improved when the correlation coefficient was above -0.70, which is more stringent compared with commonly reported criterion of -0.50, 2) longer recording durations increased the percentage of linear regressions producing correlation coefficients above -0.70 (1 min = 15%, 2 min = 28%, 5 min = 53%, 10 min = 67%, P < 0.001) and reaching statistical significance (1 min = 40%, 2 min = 69%, 5 min = 78%, 10 min = 89%, P < 0.001), 3) correlation coefficients were improved with 3-mmHg versus 1-mmHg and 2-mmHg diastolic blood pressure (BP) bin size, and 4) linear regression slopes were reduced when the acquired BP signal was not properly aligned with the cardiac cycle triggering the burst of MSNA. In summary, these results support the use of baseline recording durations of 10 min, a correlation coefficient above -0.70 for reliable linear regressions, 3-mmHg bin size, and importance of properly time-aligning MSNA and diastolic BP. Together, these findings provide best practices for determining spontaneous MSNA baroreflex sensitivity under resting conditions for improved rigor and reproducibility of results.
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Affiliation(s)
- Seth W Holwerda
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, Kansas
| | - Jason R Carter
- Department of Health and Human Development, Montana State University, Bozeman, Montana
| | - Huan Yang
- Department of Neurology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts
| | - Jing Wang
- College of Nursing, University of Texas at Arlington, Arlington, Texas
| | - Gary L Pierce
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
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60
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Stewart JM, Warsy IA, Visintainer P, Terilli C, Medow MS. Supine Parasympathetic Withdrawal and Upright Sympathetic Activation Underly Abnormalities of the Baroreflex in Postural Tachycardia Syndrome: Effects of Pyridostigmine and Digoxin. Hypertension 2021; 77:1234-1244. [PMID: 33423527 PMCID: PMC7946724 DOI: 10.1161/hypertensionaha.120.16113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Julian M Stewart
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla.,Departments of Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla
| | - Irfan A Warsy
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla
| | - Paul Visintainer
- Baystate Medical Center, University of Massachusetts School of Medicine, Worcester (P.V.)
| | - Courtney Terilli
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla
| | - Marvin S Medow
- From the Department of Pediatrics (J.M.S., I.A.W., C.T., M.S.M.), New York Medical College, Valhalla.,Departments of Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla
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61
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Young BE, Greaney JL, Keller DM, Fadel PJ. Sympathetic transduction in humans: recent advances and methodological considerations. Am J Physiol Heart Circ Physiol 2021; 320:H942-H953. [PMID: 33416453 DOI: 10.1152/ajpheart.00926.2020] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ever since their origin more than one half-century ago, microneurographic recordings of sympathetic nerve activity have significantly advanced our understanding of the generation and regulation of central sympathetic outflow in human health and disease. For example, it is now appreciated that a myriad of disease states exhibit chronic sympathetic overactivity, a significant predictor of cardiovascular morbidity and mortality. Although microneurographic recordings allow for the direct quantification of sympathetic outflow, they alone do not provide information with respect to the ensuing sympathetically mediated vasoconstriction and blood pressure (BP) response. Therefore, the study of vascular and/or BP responses to sympathetic outflow (i.e., sympathetic transduction) has now emerged as an area of growing interest within the field of neural cardiovascular control in human health and disease. To date, studies have primarily examined sympathetic transduction under two distinct paradigms: when reflexively evoking sympatho-excitation through the induction of a laboratory stressor (i.e., sympathetic transduction during stress) and/or following spontaneous bursts of sympathetic outflow occurring under resting conditions (i.e., sympathetic transduction at rest). The purpose of this brief review is to highlight how our physiological understanding of sympathetic transduction has been advanced by these studies and to evaluate the primary analytical techniques developed to study sympathetic transduction in humans. We also discuss the framework by which the assessment of sympathetic transduction during stress reflects a fundamentally different process relative to sympathetic transduction at rest and why findings from investigations using these different techniques should be interpreted as such and not necessarily be considered one and the same.
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Affiliation(s)
- Benjamin E Young
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Jody L Greaney
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - David M Keller
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
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62
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Jeong JH, Brown ML, Kapuku G, Harshfield GA, Park J. α-Adrenergic receptor blockade attenuates pressor response during mental stress in young black adults. Physiol Rep 2021; 8:e14642. [PMID: 33356011 PMCID: PMC7757373 DOI: 10.14814/phy2.14642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/13/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022] Open
Abstract
Black individuals exhibit increased blood pressure (BP) responses to sympathetic stimulation that are associated with an increased risk of hypertension (HTN). We tested the hypothesis that α1 -adrenergic blockade inhibits the increased BP response during and after 45-min stress in young normotensive Black adults, which may be mediated, in part, by dampened vasoconstriction and decreased renal sodium retention. Utilizing a double-masked randomized, crossover study design, 51 normotensive Black adults (31 ± 8 yr) were treated with either a placebo or 1 mg/day of prazosin for 1 week. On the final day of each treatment, hemodynamic measures and urinary sodium excretion (UNaV) were collected before (Rest), during (Stress) and after (Recovery) 45 min of mental stress induced via a competitive video game task. During the Stress period, diastolic BP and total peripheral resistance (TPR) were significantly lower with prazosin compared to placebo (p < .05 for both). Similarly, we observed lower systolic BP, diastolic BP, and TPR during the Recovery period with prazosin versus placebo (p < .05 for both). There was no effect of prazosin on stress-associated UNaV. The change in systolic BP from Rest to Recovery was positively associated with the change in TPR with both treatments (p < .05 for both). In summary, prazosin treatment dampened BP reactivity to 45-min mental stress and lowered post-stress BP over the recovery period, which was linked to reduce TPR in young normotensive Black adults. These results suggest that α1 -adrenergic receptor activity may contribute to BP responses and delayed BP recovery to prolonged mental stress through increased vasoconstriction in Black adults.
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Affiliation(s)
- Jin Hee Jeong
- Department of MedicineGeorgia Prevention InstituteMedical College of GeorgiaAugusta UniversityAugustaGAUSA
- Division of Renal MedicineDepartment of MedicineEmory UniversityAtlantaGAUSA
- Department of Veterans Affairs Health Care SystemDecaturGAUSA
| | - Michelle L. Brown
- Department of MedicineGeorgia Prevention InstituteMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Gaston Kapuku
- Department of MedicineGeorgia Prevention InstituteMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Gregory A. Harshfield
- Department of MedicineGeorgia Prevention InstituteMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Jeanie Park
- Division of Renal MedicineDepartment of MedicineEmory UniversityAtlantaGAUSA
- Department of Veterans Affairs Health Care SystemDecaturGAUSA
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63
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Robertson AD, Papadhima I, Edgell H. Sex differences in the autonomic and cerebrovascular responses to upright tilt. Auton Neurosci 2020; 229:102742. [PMID: 33197693 DOI: 10.1016/j.autneu.2020.102742] [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] [Received: 07/15/2020] [Revised: 10/30/2020] [Accepted: 11/02/2020] [Indexed: 01/11/2023]
Abstract
Sex differences in the regulation of autonomic and cerebrovascular responses to orthostatic stress remain unclear. The objectives of this study were to concurrently investigate autonomic control and cerebrovascular resistance indices, including critical closing pressure (CrCP) and resistance area product (RAP), during upright tilt in men and women. In 13 women and 14 men (18-29 years), ECG, non-invasive blood pressure, middle cerebral artery blood velocity, and end-tidal CO2 (ETCO2) were continuously measured during supine rest and 70° tilt. Heart rate variability (HRV), cardiovagal baroreflex sensitivity (cBRS), and transfer function parameters of dynamic cerebral autoregulation were calculated. Compared to supine, upright tilt increased the low frequency-to-high frequency ratio of HRV in men only (P = 0.044), and decreased cBRS more in women (P = 0.001). Cerebrovascular resistance index (CVRi) increased during tilt only in men (sex-by-time interaction: P = 0.004). RAP was lower in women throughout tilt (main effect of sex: P = 0.022). CrCP decreased during tilt in both sexes (main effect of time: P < 0.001). Normalizing to ETCO2 did not alter the effect of tilt on cerebrovascular resistance. Men displayed a greater increase of sympathetic indices and CVRi during tilt while women had greater parasympathetic withdrawal. We hypothesize that increased sympathetic activity in men may drive sex differences in the cerebrovascular response to upright posture.
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Affiliation(s)
- Andrew D Robertson
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada; Schlegel-UW Research Institute for Aging, University of Waterloo, Waterloo, Ontario, Canada
| | - Ismina Papadhima
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada
| | - Heather Edgell
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada; Muscle Health Research Centre, York University, Toronto, Ontario, Canada.
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64
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Stanhewicz AE, Wong BJ. Counterpoint: Investigators should not control for menstrual cycle phase when performing studies of vascular control that include women. J Appl Physiol (1985) 2020; 129:1117-1119. [DOI: 10.1152/japplphysiol.00427.2020] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Anna E. Stanhewicz
- Department of Health & Human Physiology, University of Iowa, Iowa City, Iowa
| | - Brett J. Wong
- Department of Kinesiology & Health, Georgia State University, Atlanta, Georgia
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65
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Hissen SL, Taylor CE. Sex differences in vascular transduction of sympathetic nerve activity. Clin Auton Res 2020; 30:381-392. [PMID: 32865664 DOI: 10.1007/s10286-020-00722-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/18/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE Sympathetic vasoconstriction plays a major role in the beat-to-beat control of blood pressure. To be effective and thus avoid dangerously high or low blood pressures, this mechanism relies upon transduction of sympathetic nerve activity at the level of the vasculature. However, recent evidence suggests that considerable variability exists in beat-to-beat vascular transduction, particularly between the sexes. METHODS We reviewed the methods available for quantifying beat-to-beat transduction of muscle sympathetic nerve activity (MSNA) and explored the recent evidence for sex differences in vascular transduction. We paid specific attention to relationships between vascular transduction and factors such as resting levels of sympathetic nerve activity and baroreflex sensitivity. RESULTS There are two dominant methods now available for the quantification of beat-to-beat transduction of muscle sympathetic nerve activity at rest. Whilst there is some evidence to suggest that young females exhibit lower levels of vascular transduction, results vary depending on the method used and the direction of change in MSNA. Evidence suggests that compensatory relationships may exist between key components of neurovascular control, such as vascular transduction and resting levels of MSNA. Also consistent is the presence of such relationships in young males but not young females. CONCLUSION The lack of significant relationships in young females may reflect the influence of vasodilator mechanisms that counteract sympathetic vasoconstriction. The assessment of vascular transduction following MSNA bursts and non-bursts in males and females, both young and older, may help to gain a mechanistic understanding of the prevalence of hypotensive and hypertensive disorders across the lifespan.
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Affiliation(s)
- Sarah L Hissen
- Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chloe E Taylor
- School of Health Sciences, Western Sydney University, Campbelltown Campus, Locked Bag 1797, Penrith, Sydney, NSW, 2751, Australia.
- School of Medicine, Western Sydney University, Sydney, Australia.
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66
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Prasad B, Morgan BJ, Gupta A, Pegelow DF, Teodorescu M, Dopp JM, Dempsey JA. The need for specificity in quantifying neurocirculatory vs. respiratory effects of eucapnic hypoxia and transient hyperoxia. J Physiol 2020; 598:4803-4819. [PMID: 32770545 DOI: 10.1113/jp280515] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 08/04/2020] [Indexed: 12/24/2022] Open
Abstract
KEY POINTS The carotid chemoreceptor mediates the ventilatory and muscle sympathetic nerve activity (MSNA) responses to hypoxia and contributes to tonic sympathetic and respiratory drives. It is often presumed that both excitatory and inhibitory tests of chemoreflex function show congruence in the end-organ responses. Ventilatory and neurocirculatory (MSNA, blood pressure and heart rate) responses to chemoreflex inhibition elicited by transient hyperoxia and to chemoreflex excitation produced by steady-state eucapnic hypoxia were measured in a cohort of 82 middle-aged individuals. Ventilatory and MSNA responsiveness to hyperoxia and hypoxia were not significantly correlated within individuals. It was concluded that ventilatory responses to hypoxia and hyperoxia do not predict MSNA responses and it is recommended that tests using the specific outcome of interest, i.e. MSNA or ventilation, are required. Transient hyperoxia is recommended as a sensitive and reliable means of quantifying tonic chemoreceptor-driven levels of sympathetic nervous system activity and respiratory drive. ABSTRACT Hypersensitivity of the carotid chemoreceptor leading to sympathetic nervous system activation and ventilatory instability has been implicated in the pathogenesis and consequences of several common clinical conditions. A variety of treatment approaches aimed at lessening chemoreceptor-driven sympathetic overactivity are now under investigation; thus, the ability to quantify this outcome variable with specificity and precision is crucial. Accordingly, we measured ventilatory and neurocirculatory responses to chemoreflex inhibition elicited by transient hyperoxia and chemoreflex excitation produced by exposure to graded, steady-state eucapnic hypoxia in middle-aged men and women (n = 82) with continuous positive airway pressure-treated obstructive sleep apnoea. Progressive, eucapnic hypoxia produced robust and highly variable increases in ventilation (+83 ± 59%) and muscle sympathetic nerve activity (MSNA) burst frequency (+55 ± 31%), whereas transient hyperoxia caused marked reductions in these variables (-35 ± 14% and -42 ± 16%, respectively). Coefficients of variation for ventilatory and MSNA burst frequency responses, indicating test-retest reproducibility, were respectively 9% and 24% for hyperoxia and 35% and 28% for hypoxia. Based on statistical measures of rank correlation or even comparisons across quartiles of corresponding ventilatory and MSNA responses, we found that the magnitudes of ventilatory inhibition with hyperoxia or excitation with eucapnic hypoxia were not correlated with corresponding MSNA responses within individuals. We conclude that, in conscious, behaving humans, ventilatory sensitivities to progressive, steady-state, eucapnic hypoxia and transient hyperoxia do not predict MSNA responsiveness. Our findings also support the use of transient hyperoxia as a reliable, sensitive, measure of the carotid chemoreceptor contribution to tonic sympathetic nervous system activity and respiratory drive.
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Affiliation(s)
- Bharati Prasad
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Barbara J Morgan
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.,Department of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Ahana Gupta
- GPPA Medical Scholars Program, University of Illinois at Chicago, Chicago, IL, USA
| | - David F Pegelow
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Mihaela Teodorescu
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - John M Dopp
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
| | - Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.,Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, WI, USA
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67
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Tabuchi A, Craig JC, Hirai DM, Colburn TD, Kano Y, Poole DC, Musch TI. Systemic NOS inhibition reduces contracting muscle oxygenation more in intact female than male rats. Nitric Oxide 2020; 100-101:38-44. [PMID: 32371102 DOI: 10.1016/j.niox.2020.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/14/2020] [Accepted: 04/22/2020] [Indexed: 10/24/2022]
Abstract
Females respond to baroreceptor stimulation with enhanced modulation of heart rate (HR) to regulate blood pressure and also express greater reliance on nitric oxide (NO) for vascular control compared to males. Sex differences in muscle oxygenation consequent to central hemodynamic challenge induced by systemic NO synthase (NOS) inhibition are unknown. We tested the hypotheses that systemic NOS inhibition would induce lower contracting skeletal muscle oxygenation in females compared to males. The spinotrapezius of Sprague-Dawley rats (females (♀) = 9, males (♂) = 9) was surgically exposed and contracted by electrical stimulation (180s, 1 Hz, ~6 V) under pentobarbital sodium anesthesia. Oxyphor G4 was injected into the muscle and phosphorescence quenching was used to measure the interstitial PO2 (PO2is, determined by O2 delivery-to-utilization matching) under control (Krebs-Henseleit solution) and after intra-arterial infusion of nitro-l-arginine methyl ester (l-NAME; NOS blockade; 10 mg kg-1). At rest, females showed a greater PO2is increase (ΔPO2is/ΔMAP) and HR (ΔHR/ΔMAP) reduction than males in response to the elevated MAP induced by systemic NOS inhibition (both p < 0.05). Following l-NAME, during the contracting steady-state, females exhibited lower PO2is than males (♂: 17.1 ± 1.4 vs ♀: 10.8 ± 1.4 mmHg, p < 0.05). The rate pressure product was lower in females than males (♂: 482 ± 14 vs ♀: 392 ± 29, p < 0.05) and correlated with the steady-state PO2is (r = 0.66, p < 0.05). These results support that females express greater reductions in HR than males in response to l-NAME-induced elevation of MAP via the baroreceptor reflex and provide new insights on how central hemodynamics affect skeletal muscle oxygenation in a sex-specific manner.
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Affiliation(s)
- Ayaka Tabuchi
- Departments of Kinesiology and Anatomy & Physiology, Kansas State University, Manhattan, KS, USA; Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Tokyo, Japan
| | - Jesse C Craig
- Departments of Kinesiology and Anatomy & Physiology, Kansas State University, Manhattan, KS, USA
| | - Daniel M Hirai
- Departments of Kinesiology and Anatomy & Physiology, Kansas State University, Manhattan, KS, USA
| | - Trenton D Colburn
- Departments of Kinesiology and Anatomy & Physiology, Kansas State University, Manhattan, KS, USA
| | - Yutaka Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Tokyo, Japan
| | - David C Poole
- Departments of Kinesiology and Anatomy & Physiology, Kansas State University, Manhattan, KS, USA
| | - Timothy I Musch
- Departments of Kinesiology and Anatomy & Physiology, Kansas State University, Manhattan, KS, USA.
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68
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Coovadia Y, Adler TE, Steinback CD, Fraser GM, Usselman CW. Sex differences in dynamic blood pressure regulation: beat-by-beat responses to muscle sympathetic nerve activity. Am J Physiol Heart Circ Physiol 2020; 319:H531-H538. [PMID: 32734818 DOI: 10.1152/ajpheart.00245.2020] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
It has been suggested that sex differences in acute blood pressure fluctuations occur during the periods of time between bursts of muscle sympathetic nerve activity. Therefore, we tested the hypothesis that men experience more dynamic changes in mean arterial pressure (Finometer MIDI) than women during acute sympathoinhibition (i.e., slow breathing) in which bursts of sympathetic activity occur more infrequently than at rest. We tested healthy women (n = 9) and men (n = 9) of similar age (22 ± 2 vs. 23 ± 3 yr, P = 0.6). Custom software was used to calculate beat-by-beat changes in blood pressure following sympathetic burst and nonburst sequences (recorded using microneurography) during 10 min of supine rest and a 15-min bout of slow breathing. During slow breathing following nonburst sequences, women demonstrated smaller overall reductions in mean arterial pressure compared with men over the subsequent 15 cardiac cycles (P < 0.01). In addition, following a burst of sympathetic activity, women experienced greater overall increases in mean arterial pressure compared with men over the following 15 cardiac cycles (P < 0.01). Despite these differences, the peak and nadir changes in arterial pressure following burst and nonburst sequences were not different between the sexes (P = 0.45 and P = 0.48, burst and nonburst sequences, respectively). As such, these data suggest that women respond to a burst of sympathetic activity with more sustained increases in blood pressure than men, coupled with improved maintenance of blood pressure during acute periods of sympathetic quiescence. In other words, these findings suggest that men rely more on frequent bursts of sympathetic activity to acutely regulate arterial pressure than women.NEW & NOTEWORTHY We demonstrate that during acute sympathoinhibition, women demonstrate more sustained increases in blood pressure following sympathetic bursts of activity than men. Likewise, during prolonged sympathetic quiescence, blood pressure is less labile in women than men. This suggests that lower overall blood pressure in young women may not be mediated by smaller beat-by-beat changes in blood pressure in response to sympathetic outflow but may instead be mediated by a lower frequency of sympathetic bursts.
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Affiliation(s)
- Yasmine Coovadia
- Cardiovascular Health and Autonomic Regulation Laboratory, Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | - Tessa E Adler
- Cardiovascular Health and Autonomic Regulation Laboratory, Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | - Craig D Steinback
- Neurovascular Health Laboratory, Program for Pregnancy and Postpartum Health, Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Graham M Fraser
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador
| | - Charlotte W Usselman
- Cardiovascular Health and Autonomic Regulation Laboratory, Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada.,McGill Research Centre for Physical Activity and Health, McGill University, Montreal, Quebec, Canada
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69
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Ely MR, Ratchford SM, La Salle DT, Trinity JD, Wray DW, Halliwill JR. Effect of histamine-receptor antagonism on leg blood flow during exercise. J Appl Physiol (1985) 2020; 128:1626-1634. [PMID: 32407239 DOI: 10.1152/japplphysiol.00689.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Histamine mediates vasodilation during inflammatory and immune responses, as well as following endurance exercise. During exercise, intramuscular histamine concentration increases, and its production, appears related to exercise intensity and duration. However, whether histamine contributes to exercise hyperemia and promotes exercise blood flow in an intensity- or duration-dependent pattern is unknown. The purpose of this study was to compare leg blood flow across a range of exercise intensities, before and after prolonged exercise, with and without histamine-receptor antagonism. It was hypothesized that combined oral histamine H1/H2-receptor antagonism would decrease leg blood flow, and the effect would be greater at higher intensities and following prolonged exercise. Sixteen (7F, 9M) volunteers performed single-leg knee-extension exercise after consuming either placebo or combined histamine H1/H2-receptor antagonists (Blockade). Exercise consisted of two graded protocols at 20, 40, 60, and 80% of peak power, separated by 60 min of knee-extension exercise at 60% of peak power. Femoral artery blood flow was measured by ultrasonography. Femoral artery blood flow increased with exercise intensity up to 2,660 ± 97 mL/min at 80% of peak power during Placebo (P < 0.05). Blood flow was further elevated with Blockade to 2,836 ± 124 mL/min (P < 0.05) at 80% peak power (9.1 ± 4.8% higher than placebo). These patterns were not affected by prolonged exercise (P = 0.13). On average, femoral blood flow during prolonged exercise was 12.7 ± 2.8% higher with Blockade vs. Placebo (P < 0.05). Contrary to the hypothesis, these results suggest that histamine receptor antagonism during exercise, regardless of intensity or duration, increases leg blood flow measured by ultrasonography.NEW & NOTEWORTHY Leg blood flow during exercise was increased by taking antihistamines, which block the receptors for histamine, a molecule often associated with inflammatory and immune responses. The elevated blood flow occurred over exercise intensities ranging from 20 to 80% of peak capacity and during exercise of 60 min duration. These results suggest that exercise-induced elevations in histamine concentrations are involved in novel, poorly understood, and perhaps complex ways in the exercise response.
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Affiliation(s)
- Matthew R Ely
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Stephen M Ratchford
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - D Taylor La Salle
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Joel D Trinity
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - D Walter Wray
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - John R Halliwill
- Department of Human Physiology, University of Oregon, Eugene, Oregon
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Salman IM, Ameer OZ, McMurray S, Giarola AS, Sridhar A, Lewis SJ, Hsieh YH. Laterality Influences Central Integration of Baroreceptor Afferent Input in Male and Female Sprague Dawley Rats. Front Physiol 2020; 11:499. [PMID: 32536876 PMCID: PMC7269127 DOI: 10.3389/fphys.2020.00499] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/23/2020] [Indexed: 12/02/2022] Open
Abstract
We explored the effects of baroreceptor afferents laterality and sexual dimorphism on the expression of cardiovascular reflex responses to baroreflex activation in Sprague Dawley (SD) rats. Under urethane anesthesia, rats of either sex (total n = 18) were instrumented for left, right and bilateral aortic depressor nerve (ADN) stimulation (1–40 Hz, 0.2 ms, 0.4 mA for 20 s) and measurement of mean arterial pressure (MAP), heart rate (HR) and mesenteric (MVR) and femoral (FVR) vascular resistance. Female rats were matched for the diestrus phase of the estrus cycle. Left, right and bilateral ADN stimulation evoked frequency-dependent drops in MAP, HR, and MVR, and increases in FVR. Irrespective of sex, left and bilateral ADN stimulation as compared to right-sided stimulation mediated greater reflex reductions in MAP, HR, and MVR but not in FVR. In males, reflex bradycardic responses were greater in response to bilateral stimulation relative to both left- and right-sided stimulation. In females, left ADN stimulation evoked the largest increase in FVR. Left and bilateral ADN stimulations evoked greater reductions in MAP and MVR while left-sided stimulation produced larger increases in FVR in females compared with males. All other reflex responses to ADN stimulation were relatively comparable between males and females. These results show a differential baroreflex processing of afferent neurotransmission promoted by left versus right baroreceptor afferent inputs and sexual dimorphism in the expression of baroreflex responses in rats of either sex. Collectively, these data add to our understanding of physiological mechanisms pertaining to baroreflex control in both males and females.
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Affiliation(s)
- Ibrahim M Salman
- College of Pharmacy, Alfaisal University, Riyadh, Saudi Arabia.,Division of Pulmonology, Allergy and Immunology, Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Omar Z Ameer
- College of Pharmacy, Alfaisal University, Riyadh, Saudi Arabia
| | - Sheridan McMurray
- Department of Disease Biology, Galvani Bioelectronics, Hertfordshire, United Kingdom
| | - Alessandra S Giarola
- Department of Disease Biology, Galvani Bioelectronics, Hertfordshire, United Kingdom
| | - Arun Sridhar
- Department of Disease Biology, Galvani Bioelectronics, Hertfordshire, United Kingdom
| | - Stephen J Lewis
- Division of Pulmonology, Allergy and Immunology, Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
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71
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Smith JR, Bruhn EJ, Berg JD, Nur AA, Villarraga N, Olson TP. Combined influence of inspiratory loading and locomotor subsystolic cuff inflation on cardiovascular responses during submaximal exercise. J Appl Physiol (1985) 2020; 128:1338-1345. [PMID: 32240016 DOI: 10.1152/japplphysiol.00781.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is unknown if simultaneous stimulation of the respiratory and locomotor muscle afferents via inspiratory loading (IL) and locomotor subsystolic cuff inflation (CUFF) influences the cardiovascular responses during exercise. We hypothesized that combined IL and CUFF (IL + CUFF) will result in greater increases in blood pressure (MAP) and systemic vascular resistance (SVR) than IL and CUFF alone during exercise. Eight adults (6 males/2 females) were enrolled and performed four 10-min bouts of constant-load cycling eliciting 40% maximal oxygen uptake on a single day. For each exercise bout, the first 5 min consisted of spontaneous breathing. The second 5 min consisted of voluntary hyperventilation (i.e., breathing frequency of 40 breaths/min) with IL (30% maximum inspiratory pressure), CUFF (80 mmHg), IL + CUFF, or no intervention (CTL) in randomized order. During exercise, cardiac output and MAP were determined via open-circuit acetylene wash-in and manual sphygmomanometry, respectively, and SVR was calculated. Across CTL, IL, CUFF, and IL + CUFF, MAP was greater with each condition (CTL: 97 ± 14; IL: 106 ± 13; CUFF: 114 ± 14; IL + CUFF: 119 ± 15 mmHg, all P < 0.02). Furthermore, SVR was greater with IL + CUFF compared with IL, CUFF, and CTL (CTL: 6.6 ± 1.1; IL: 7.5 ± 1.4; CUFF: 7.5 ± 1.3; IL + CUFF: 8.2 ± 1.4 mmHg·L-1·min-1, all P < 0.02). Cardiac output was not different across conditions (CTL: 15.2 ± 3.8; IL: 14.8 ± 3.7; CUFF: 15.6 ± 3.5; IL + CUFF: 14.7 ± 4.3 L/min, all P > 0.05). These data demonstrate that simultaneous stimulation of respiratory and locomotor muscle afferent feedback results in additive MAP and SVR responses than IL and CUFF alone during submaximal exercise. These findings have important clinical implications for populations with exaggerated locomotor and respiratory muscle reflex feedbacks.NEW & NOTEWORTHY Reflexes arising from the respiratory and locomotor muscles influence cardiovascular regulation during exercise. However, it is unclear how the respiratory and locomotor muscle reflexes interact when simultaneously stimulated. Herein, we demonstrate that stimulation of the respiratory and locomotor muscle reflexes yielded additive cardiovascular responses during submaximal exercise.
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Affiliation(s)
- Joshua R Smith
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota
| | - Eric J Bruhn
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota
| | - Jessica D Berg
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota
| | - Amran A Nur
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota
| | | | - Thomas P Olson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota
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72
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Baker SE, Limberg JK, Scruggs ZM, Curry TB, Nicholson WT, Barnes JN, Joyner MJ. Greater Influence of Aerobic Fitness on Autonomic Support of Blood Pressure in Young Women Than in Older Women. Hypertension 2020; 75:1497-1504. [PMID: 32336237 DOI: 10.1161/hypertensionaha.119.14042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aging increases autonomic support of blood pressure; however, the impact of aerobic fitness on autonomic support of blood pressure has not been addressed in women. As such, we hypothesized that aerobic fitness would be related to the change in blood pressure during ganglionic blockade such that women with greater aerobic fitness would have a blunted fall in blood pressure during ganglionic blockade due to increased vagal tone. Thirteen young premenopausal and 13 older postmenopausal women completed a screening visit where aerobic fitness (maximal oxygen consumption, VO2max) was measured. On a separate study day, participants were instrumented for assessment of muscle sympathetic nerve activity, heart rate (electrocardiography), and beat by beat blood pressure (arterial catheter and pressure transducer) and underwent pharmacological blockade of the autonomic ganglia using trimethaphan camyslate. Heart rate, blood pressure, and muscle sympathetic nerve activity were analyzed before and during ganglionic blockade. In young women, there was a significant relationship between aerobic fitness and the change in blood pressure during ganglionic blockade (r=0.761, P=0.003). In older women, there was no relationship between aerobic fitness and the change in blood pressure during ganglionic blockade (r=-0.106, P=0.73). Measures of heart rate variability were related to fitness in young women, but not older women (root mean square of successive differences between normal heartbeats, r=0.713, P=0.006 versus r=-0.172, P=0.575). Our data suggest that in young women, autonomic support of blood pressure is attenuated in those that are highly fit; however, this relationship is not significant in older women.
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Affiliation(s)
- Sarah E Baker
- From the Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN (S.E.B., Z.M.S., T.B.C., W.R.N., M.J.J.)
| | - Jacqueline K Limberg
- Department of Nutrition & Exercise Physiology, University of Missouri, Columbia (J.K.L.)
| | - Zachariah M Scruggs
- From the Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN (S.E.B., Z.M.S., T.B.C., W.R.N., M.J.J.)
| | - Timothy B Curry
- From the Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN (S.E.B., Z.M.S., T.B.C., W.R.N., M.J.J.)
| | - Wayne T Nicholson
- From the Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN (S.E.B., Z.M.S., T.B.C., W.R.N., M.J.J.)
| | - Jill N Barnes
- Department of Kinesiology, University of Wisconsin, Madison (J.N.B.)
| | - Michael J Joyner
- From the Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN (S.E.B., Z.M.S., T.B.C., W.R.N., M.J.J.)
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73
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Ferreira MJ, Sanches IC, Jorge L, Llesuy SF, Irigoyen MC, De Angelis K. Ovarian status modulates cardiovascular autonomic control and oxidative stress in target organs. Biol Sex Differ 2020; 11:15. [PMID: 32264929 PMCID: PMC7140311 DOI: 10.1186/s13293-020-00290-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 03/18/2020] [Indexed: 01/08/2023] Open
Abstract
Studies have presented conflicting findings regarding the association between both fluctuation and deprivation of ovarian hormones and cardiovascular autonomic modulation and oxidative stress and their potential impact on resting arterial pressure (AP) and cardiovascular risk. This study aimed to assess cardiovascular autonomic modulation, baroreflex sensitivity (BRS), and oxidative stress in male rats (M) and in female rats during ovulatory (FOV) and non-ovulatory phases (FNOV) of the estrous cycle and after deprivation of ovarian hormones (FO). Direct AP was recorded, and BRS was assessed by using increasing doses of phenylephrine and sodium nitroprusside. AP and heart rate variability were assessed by spectral analysis. Oxidative stress profile was evaluated in cardiac, renal, and muscle tissues. In females, the ovulatory phase and ovarian hormone deprivation induced an increase in AP (FOV and FO ~ 9 mmHg) when compared to the non-ovulatory phase. Ovariectomy promoted increased cardiac sympathovagal balance (~ 17–37%) when compared to other groups. Both FOV and FO groups presented impaired BRS, associated with higher AP variability. In general, antioxidant capacity was higher in the FNOV than in the M group. Ovarian hormone deprivation induced a decrease in catalase activity in cardiac and renal tissues and an increase in lipid peroxidation in all tissues analyzed. Positive correlations (p < 0.05) were found between vascular sympathetic modulation and lipid peroxidation in cardiac (r = 0.60), renal (r = 0.60), and muscle (r = 0.57) tissues. In conclusion, both oscillation and deprivation of ovarian hormones play an important role in cardiovascular autonomic control and oxidative stress profile in target organs, which is reflected in AP changes.
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Affiliation(s)
- Maycon Junior Ferreira
- Physiology Exercise Laboratory, Department of Physiology, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
| | - Iris Callado Sanches
- Human Movement Laboratory, Sao Judas Tadeu University (USJT), Sao Paulo, SP, Brazil
| | - Luciana Jorge
- Hypertension Unit, Heart Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - Susana Francisca Llesuy
- University Institute of Italian Hospital, Italian Hospital of Buenos Aires (HIBA), Buenos Aires, Argentina
| | | | - Kátia De Angelis
- Physiology Exercise Laboratory, Department of Physiology, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil. .,Laboratory of Translational Physiology, Nove de Julho University (UNINOVE), Sao Paulo, SP, Brazil.
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74
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Yamagata T, Sako T. High cardiovascular reactivity and muscle strength attenuate hypotensive effects of isometric handgrip training in young women: A randomized controlled trial. Clin Exp Hypertens 2020; 42:595-600. [PMID: 32249609 DOI: 10.1080/10641963.2020.1747482] [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] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Isometric resistance training may reduce resting blood pressure (BP); however, the magnitude of this effect varies among individual subjects and few studies attempted to predict it. This study aimed to investigate the potential hypotensive effects of isometric training and their association with cardiovascular reactivity to acute isometric exercise and muscle strength in young women. METHODS In this randomized trial, twenty young women were randomly assigned to either the training (n = 10) or control (n = 10) group. Women from the training group performed unilateral isometric handgrip sessions for 8 weeks (4 × 2 min at 25% of maximal voluntary contraction [MVC]; 3 days/week). Cardiovascular reactivity to acute isometric exercise and MVC were measured at baseline. Resting BP was assessed during and after the intervention. RESULTS Resting systolic BP significantly lowered only in the training group. The change in resting systolic BP following an 8-week intervention was significantly associated with the systolic BP and diastolic BP reactivity to the acute exercise at baseline during set 3 and 4 (P <.05). The handgrip MVC was associated with changes in systolic BP (r = 0.79, P =.007), diastolic BP (r = 0.68, P =.032), and mean arterial pressure (r = 0.79, P =.006). These results indicated that high cardiovascular reactivity and strength attenuate the hypotensive effects following isometric training in young women. CONCLUSIONS The hypotensive effects following isometric training may be identified by BP reactivity to acute isometric exercise or handgrip strength in young women.
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Affiliation(s)
- Takashi Yamagata
- Department of Clothing, Faculty of Human Sciences and Design, Japan Women's University , Tokyo, Japan
| | - Takayuki Sako
- Department of Food and Nutrition, Faculty of Human Sciences and Design, Japan Women's University , Tokyo, Japan
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75
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Abstract
Baroreceptors are mechanosensitive elements of the peripheral nervous system that maintain homeostasis by coordinating physiologic responses to external and internal stimuli. While it is recognized that carotid and cardiopulmonary baroreceptor reflexes modulate autonomic output to mitigate excessive fluctuations in arterial blood pressure and to maintain intravascular volume, increasing evidence suggests that baroreflex pathways also project to key regions of the central nervous system that regulate somatosensory, somatomotor, and central nervous system arousal. In addition to maintaining autonomic homeostasis, baroreceptor activity modulates the perception of pain, as well as neuroimmune, neuroendocrine, and cognitive responses to physical and psychologic stressors. This review summarizes the role that baroreceptor pathways play in modulating acute and chronic pain perception. The contribution of baroreceptor function to postoperative outcomes is also presented. Finally, methods that enhance baroreceptor function, which hold promise in improving postoperative and pain management outcomes, are presented.
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76
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Baker FC, Siboza F, Fuller A. Temperature regulation in women: Effects of the menstrual cycle. Temperature (Austin) 2020; 7:226-262. [PMID: 33123618 PMCID: PMC7575238 DOI: 10.1080/23328940.2020.1735927] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/17/2020] [Accepted: 02/24/2020] [Indexed: 02/08/2023] Open
Abstract
Core body temperature changes across the ovulatory menstrual cycle, such that it is 0.3°C to 0.7°C higher in the post-ovulatory luteal phase when progesterone is high compared with the pre-ovulatory follicular phase. This temperature difference, which is most evident during sleep or immediately upon waking before any activity, is used by women as a retrospective indicator of an ovulatory cycle. Here, we review both historical and current literature aimed at characterizing changes in core body temperature across the menstrual cycle, considering the assessment of the circadian rhythm of core body temperature and thermoregulatory responses to challenges, including heat and cold exposure, exercise, and fever. We discuss potential mechanisms for the thermogenic effect of progesterone and the temperature-lowering effect of estrogen, and discuss effects on body temperature of exogenous formulations of these hormones as contained in oral contraceptives. We review new wearable temperature sensors aimed at tracking daily temperature changes of women across multiple menstrual cycles and highlight the need for future research on the validity and reliability of these devices. Despite the change in core body temperature across the menstrual cycle being so well identified, there remain gaps in our current understanding, particularly about the underlying mechanisms and microcircuitry involved in the temperature changes.
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Affiliation(s)
- Fiona C. Baker
- Center for Health Sciences, SRI International, Menlo Park, USA
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Felicia Siboza
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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77
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Liu SH, Lai CT, Chen HR, Lin WL, Yamada S, Lugtu IC, Chou YH, Yang CC, Kuo TBJ, Chen SA, Lo LW. The Impact of Estrogen Supplementation to Autonomic and Sleep Modulations in Free-Moving Spontaneously Hypertensive Rats. Int Heart J 2020; 61:128-137. [DOI: 10.1536/ihj.19-297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Shin-Huei Liu
- Division of Cardiology, Taipei Veterans General Hospital
| | - Chun-Ting Lai
- Institute of Brain Science, National Yang-Ming University
- Sleep Research Center, National Yang-Ming University
| | | | - Wei-Lun Lin
- Division of Cardiology, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University
| | - Shinya Yamada
- Division of Cardiology, Taipei Veterans General Hospital
| | | | - Yu-Hui Chou
- Division of Cardiology, Taipei Veterans General Hospital
| | - Cheryl C.H. Yang
- Institute of Brain Science, National Yang-Ming University
- Sleep Research Center, National Yang-Ming University
| | - Terry Bo-Jau Kuo
- Institute of Brain Science, National Yang-Ming University
- Sleep Research Center, National Yang-Ming University
- Digital Medicine Center, National Yang-Ming University
| | - Shih-Ann Chen
- Division of Cardiology, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University
| | - Li-Wei Lo
- Division of Cardiology, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University
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78
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Stuckless TJR, Vermeulen TD, Brown CV, Boulet LM, Shafer BM, Wakeham DJ, Steinback CD, Ayas NT, Floras JS, Foster GE. Acute intermittent hypercapnic hypoxia and sympathetic neurovascular transduction in men. J Physiol 2020; 598:473-487. [PMID: 31805605 DOI: 10.1113/jp278941] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/03/2019] [Indexed: 01/02/2023] Open
Abstract
KEY POINTS Intermittent hypoxia leads to long-lasting increases in muscle sympathetic nerve activity and blood pressure, contributing to increased risk for hypertension in obstructive sleep apnoea patients. We determined whether augmented vascular responses to increasing sympathetic vasomotor outflow, termed sympathetic neurovascular transduction (sNVT), accompanied changes in blood pressure following acute intermittent hypercapnic hypoxia in men. Lower body negative pressure was utilized to induce a range of sympathetic vasoconstrictor firing while measuring beat-by-beat blood pressure and forearm vascular conductance. IH reduced vascular shear stress and steepened the relationship between diastolic blood pressure and sympathetic discharge frequency, suggesting greater systemic sNVT. Our results indicate that recurring cycles of acute intermittent hypercapnic hypoxia characteristic of obstructive sleep apnoea could promote hypertension by increasing sNVT. ABSTRACT Acute intermittent hypercapnic hypoxia (IH) induces long-lasting elevations in sympathetic vasomotor outflow and blood pressure in healthy humans. It is unknown whether IH alters sympathetic neurovascular transduction (sNVT), measured as the relationship between sympathetic vasomotor outflow and either forearm vascular conductance (FVC; regional sNVT) or diastolic blood pressure (systemic sNVT). We tested the hypothesis that IH augments sNVT by exposing healthy males to 40 consecutive 1 min breathing cycles, each comprising 40 s of hypercapnic hypoxia ( P ETC O 2 : +4 ± 3 mmHg above baseline; P ET O 2 : 48 ± 3 mmHg) and 20 s of normoxia (n = 9), or a 40 min air-breathing control (n = 7). Before and after the intervention, lower body negative pressure (LBNP; 3 min at -15, -30 and -45 mmHg) was applied to elicit reflex increases in muscle sympathetic nerve activity (MSNA, fibular microneurography) when clamping end-tidal gases at baseline levels. Ventilation, arterial pressure [systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP)], brachial artery blood flow ( Q ̇ BA ), FVC ( Q ̇ BA /MAP) and MSNA burst frequency were measured continuously. Following IH, but not control, ventilation [5 L min-1 ; 95% confidence interval (CI) = 1-9] and MAP (5 mmHg; 95% CI = 1-9) were increased, whereas FVC (-0.2 mL min-1 mmHg-1 ; 95% CI = -0.0 to -0.4) and mean shear rate (-21.9 s-1 ; 95% CI = -5.8 to -38.0; all P < 0.05) were reduced. Systemic sNVT was increased following IH (0.25 mmHg burst-1 min-1 ; 95% CI = 0.01-0.49; P < 0.05), whereas changes in regional forearm sNVT were similar between IH and sham. Reductions in vessel wall shear stress and, consequently, nitric oxide production may contribute to heightened systemic sNVT and provide a potential neurovascular mechanism for elevated blood pressure in obstructive sleep apnoea.
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Affiliation(s)
- Troy J R Stuckless
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Tyler D Vermeulen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Courtney V Brown
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Brooke M Shafer
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Denis J Wakeham
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Craig D Steinback
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Najib T Ayas
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - John S Floras
- University Health Network and Mount Sinai Hospital Division of Cardiology, Toronto, ON, Canada.,Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
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Shimizu K, Shiozawa K, Ishida K, Saito M, Mizuno S, Akima H, Katayama K. Blood pressure and limb blood flow responses during hyperpnoea are not affected by menstrual cycle phase in young women. Respir Physiol Neurobiol 2020; 275:103387. [PMID: 31945516 DOI: 10.1016/j.resp.2020.103387] [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: 06/25/2019] [Revised: 01/11/2020] [Accepted: 01/11/2020] [Indexed: 12/18/2022]
Abstract
The purpose of this study was to clarify whether the menstrual cycle affects the cardiovascular and limb blood flow responses during hyperpnoea. Fifteen young female subjects participated. An incremental respiratory endurance test was performed at the early follicular (EF) and midluteal (ML) phases. Target minute ventilation was initially set at 30 % of maximal voluntary ventilation (MVV12) and was increased by 10 %MVV12 every 3 min. The test was terminated when the subjects no longer maintained the target ventilation. Mean arterial blood pressure (MBP) and mean blood flow in the brachial artery were continuously measured. There were no significant differences in the increase in MBP (EF: +13.0 ± 7.9 mmHg vs. ML: + 15.4 ± 12.9 mmHg during the test, F = 0.70, P = 0.59) and the decrease in brachial blood flow between the phases. These results suggest that menstrual cycle does not affect respiratory muscle-induced metaboreflex in young women.
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Affiliation(s)
- Kaori Shimizu
- Graduate School of Education and Human Development, Nagoya University, Nagoya, Japan
| | - Kana Shiozawa
- Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Koji Ishida
- Graduate School of Medicine, Nagoya University, Nagoya, Japan; Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan
| | - Mitsuru Saito
- Applied Physiology Laboratory, Toyota Technological Institute, Nagoya, Japan
| | - Sahiro Mizuno
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan; Research Fellow of Japan Society for the Promotion of Science, Japan
| | - Hiroshi Akima
- Graduate School of Education and Human Development, Nagoya University, Nagoya, Japan; Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan
| | - Keisho Katayama
- Graduate School of Medicine, Nagoya University, Nagoya, Japan; Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.
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80
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Dillon GA, Shepherd JR, Casey DP, Dinenno FA, Curry TB, Joyner MJ, Ranadive SM. Rapid-onset vasodilator responses to exercise in humans: Effect of increased baseline blood flow. Exp Physiol 2020; 105:88-95. [PMID: 31762131 PMCID: PMC6938538 DOI: 10.1113/ep088227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 11/22/2019] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the effect of an elevated baseline blood flow, induced by high-dose intra-arterial infusion of either adenosine or ATP, on the rapid-onset vasodilatory response to a single forearm muscle contraction? What is the main finding and its importance? The peak response to a single contraction is unaffected by augmented baseline blood flow, and thus, is likely to be attributable to a feedforward vasodilatory mechanism. ABSTRACT The hyperaemic responses to single muscle contractions are proportional to exercise intensity, which, in turn, is proportional to tissue metabolic demand. Hence, we tested the hypothesis that the rapid-onset vasodilatory response after a single muscle contraction would be unaffected when baseline blood flow was increased via high-dose intra-arterial infusion of either adenosine (ADO) or ATP. Twenty-four healthy young participants (28 ± 1 years) performed a single forearm contraction (20% maximal voluntary contraction) 75 min after commencement of a continuous infusion of ADO (n = 6), ATP (n = 8) or saline (control; n = 10). Brachial artery diameter and blood velocity were measured using Doppler ultrasound. Resting forearm vascular conductance (FVC; in millilitres per minute per 100 mmHg per decilitre of forearm volume) was significantly higher during ADO (33 ± 17) and ATP infusion (33 ± 17) compared with the control infusion (8 ± 3; P < 0.05). The peak FVCs post-contraction during ADO and ATP infusions were significantly greater than during the control infusion (P < 0.05), but not different from one another. The peak change in FVC from baseline was similar in all three conditions (control, 14 ± 1; ADO, 24 ± 2; and ATP, 23 ± 6; P = 0.15). Total FVC (area under the curve) did not differ significantly between ADO and ATP (333 ± 69 and 440 ± 125); however, total FVC during ATP infusion was significantly greater compared with the control value (150 ± 19; P < 0.05). We conclude that the peak response to a single contraction is unaffected by augmented baseline blood flow and is therefore likely to be attributable to a feedforward vasodilatory mechanism.
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Affiliation(s)
- Gabrielle A. Dillon
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905 United States
| | - John R.A. Shepherd
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905 United States
| | - Darren P. Casey
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242 United States
| | - Frank A. Dinenno
- Department of Health and Exercise Science, and Center for Cardiovascular Research, Colorado State University, Fort Collins, CO 80523 United States
| | - Timothy B. Curry
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905 United States
| | - Michael J. Joyner
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905 United States
| | - Sushant M. Ranadive
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905 United States
- Department of Kinesiology, University of Maryland, College Park, MD 20742 United States
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Davydov DM, Shahabi L, Naliboff B. Cardiovascular phenotyping for personalized lifestyle treatments of chronic abdominal pain in Irritable Bowel Syndrome: A randomized pilot study. Neurogastroenterol Motil 2019; 31:e13710. [PMID: 31429514 PMCID: PMC6861616 DOI: 10.1111/nmo.13710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/30/2019] [Accepted: 08/08/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND Different physical exercise interventions for pain and other related symptoms largely follow non-personalized guidelines and show a high degree of variability in outcome. These interventions are considered to have different pathways toward improvement in autonomic regulation of energy metabolism. The current pilot study was conducted to assess the predictive value of individual cardiovascular (CV) activity markers at rest to predict clinical outcomes for two popular exercise-based interventions (walking and yoga) in patients with Irritable Bowel Syndrome (IBS). METHODS Twenty-seven adult participants with IBS were randomly assigned to a 16-biweekly Iyengar yoga or walking program. They completed pre- and post-treatment assessments on IBS symptom severity, affective and somatic complaints, and various measures of resting autonomic function including blood pressure (BP), heart rate and its variability, baroreceptor sensitivity (BRS) to activations and inhibitions with gains of brady- and tachycardiac baro-responses, and BP start points for these spontaneous baroreflexes. RESULTS Pretreatment BRS was differentially related to clinical response for the treatment groups. Specifically, a significant decrease in pain severity was found in response to yoga for those participants who had lower resting BRS to activations, but decreased pain severity was associated with higher resting BRS for those in the walking group. The effect was not related to affective symptom relief. Other CV measures showed similar associations with clinical outcomes for both groups. CONCLUSIONS The data suggest therefore that CV based phenotypes may be useful in personalizing clinical interventions for IBS. They may also point to autonomic mechanisms that are targets for such interventions.
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Affiliation(s)
- Dmitry M. Davydov
- Laboratory of Neuroimmunopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, 8 Baltiyskaia ul., Moscow, 125315, Russia
| | - Leila Shahabi
- Departments of Medicine, Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095
| | - Bruce Naliboff
- Departments of Medicine, Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, 760 Westwood Plaza, Los Angeles, CA 90095
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82
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Schmalenberger KM, Eisenlohr-Moul TA, Würth L, Schneider E, Thayer JF, Ditzen B, Jarczok MN. A Systematic Review and Meta-Analysis of Within-Person Changes in Cardiac Vagal Activity across the Menstrual Cycle: Implications for Female Health and Future Studies. J Clin Med 2019; 8:jcm8111946. [PMID: 31726666 PMCID: PMC6912442 DOI: 10.3390/jcm8111946] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/01/2019] [Accepted: 11/04/2019] [Indexed: 12/11/2022] Open
Abstract
Interest in cardiac vagal activity (CVA; e.g., parasympathetically-mediated heart rate variability) as a biomarker of physical and mental health has increased exponentially in recent years. However, the understanding of sources of within-person change (i.e., intra-individual variance) in CVA is lagging behind. This systematic review and meta-analysis summarizes and quantifies current empirical evidence of within-person changes in measures of CVA across the menstrual cycle in naturally-cycling premenopausal females. We conducted an extensive literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement in five databases to identify observational studies with repeated measures of CVA in at least two menstrual cycle phases. A broad meta-analysis (nstudies = 37; nindividuals = 1,004) revealed a significant CVA decrease from the follicular to luteal phase (d = −0.39, 95% CI (−0.67, −0.11)). Furthermore, 21 studies allowed for finer-grained comparisons between each of two cycle phases (menstrual, mid-to-late follicular, ovulatory, early-to-mid luteal, and premenstrual). Significant decreases in CVA were observed from the menstrual to premenstrual (nstudies = 5; nindividuals = 200; d = −1.17, 95% CI (−2.18, −0.17)) and from the mid-to-late follicular to premenstrual phases (nstudies = 8; nindividuals = 280; d = −1.32, 95% CI (−2.35, −0.29)). In conclusion, meta-analyses indicate the presence of CVA fluctuations across the menstrual cycle. Future studies involving CVA should control for cycle phase. Recommendations for covarying or selecting cycle phase are provided.
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Affiliation(s)
- Katja M. Schmalenberger
- Institute of Medical Psychology, Center for Psychosocial Medicine, University Hospital Heidelberg, 69115 Heidelberg, Germany; (L.W.); (E.S.); (B.D.)
- Correspondence: (K.M.S.); (M.N.J.); Tel.: +49-6221-56-8148 (K.M.S.); +49-731-500-61810 (M.N.J.)
| | - Tory A. Eisenlohr-Moul
- Women’s Mental Health Research Program, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA;
| | - Lena Würth
- Institute of Medical Psychology, Center for Psychosocial Medicine, University Hospital Heidelberg, 69115 Heidelberg, Germany; (L.W.); (E.S.); (B.D.)
| | - Ekaterina Schneider
- Institute of Medical Psychology, Center for Psychosocial Medicine, University Hospital Heidelberg, 69115 Heidelberg, Germany; (L.W.); (E.S.); (B.D.)
| | - Julian F. Thayer
- Department of Psychological Science, School of Social Ecology, University of California Irvine, Irvine, CA 92697-7085, USA
| | - Beate Ditzen
- Institute of Medical Psychology, Center for Psychosocial Medicine, University Hospital Heidelberg, 69115 Heidelberg, Germany; (L.W.); (E.S.); (B.D.)
| | - Marc N. Jarczok
- Clinic for Psychosomatic Medicine and Psychotherapy, Ulm University Medical Center, 89081 Ulm, Germany
- Correspondence: (K.M.S.); (M.N.J.); Tel.: +49-6221-56-8148 (K.M.S.); +49-731-500-61810 (M.N.J.)
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83
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Smith JR, Koepp KE, Berg JD, Akinsanya JG, Olson TP. Influence of Sex, Menstrual Cycle, and Menopause Status on the Exercise Pressor Reflex. Med Sci Sports Exerc 2019; 51:874-881. [PMID: 30986812 DOI: 10.1249/mss.0000000000001877] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this review, we highlight the underlying mechanisms responsible for the sex differences in the exercise pressor reflex (EPR), and, importantly, the impact of sex hormones and menopausal status. The EPR is attenuated in premenopausal women compared with age-matched men. Specifically, activation of the metaboreflex (a component of the EPR) results in attenuated increases in blood pressure and sympathetic vasomotor outflow compared with age-matched men. In addition, premenopausal women exhibit less transduction of sympathetic outflow to the peripheral vasculature than men. In stark contrast, postmenopausal women exhibit an augmented EPR arising from exaggerated metaboreflex-induced autonomic and cardiovascular reflexes. We propose that metaboreflex-induced autonomic and cardiovascular changes associated with menopause majorly contribute to the elevated blood pressure response during dynamic exercise in postmenopausal women. In addition, we discuss the potential mechanisms by which sex hormones in premenopausal women may impact the EPR as well as metaboreflex.
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Affiliation(s)
- Joshua R Smith
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
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84
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Fecchio RY, Brito L, Leicht AS, Forjaz CL, Peçanha T. Reproducibility of post-exercise heart rate recovery indices: A systematic review. Auton Neurosci 2019; 221:102582. [DOI: 10.1016/j.autneu.2019.102582] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/03/2019] [Accepted: 08/21/2019] [Indexed: 01/14/2023]
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85
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Fu Q, Ogoh S. Sex differences in baroreflex function in health and disease. J Physiol Sci 2019; 69:851-859. [PMID: 31721084 PMCID: PMC10717578 DOI: 10.1007/s12576-019-00727-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/29/2019] [Indexed: 01/16/2023]
Abstract
This brief review summarizes the current knowledge on sex differences in baroreflex function, with a major focus on studies in humans. It has been demonstrated that healthy women have blunted cardiovagal baroreflx sensitivity during a rapid (i.e., within seconds) hypertensive stimulus, but baroreflex sensitivity is similar between the sexes during a hypotensive stimulus. Normal aging decreases cardiovagal baroreflex sensitivity and the rate of decline is similar in men and women. Cardiovagal baroreflex sensitivity is reduced in pathological conditions such as hypertension and type II diabetes, and the reduction is greater in female patients than male patients. There is no clear sex difference in sympathetic baroreflex sensitivity among young individuals, however, with women of more advanced age, sympathetic baroreflex sensitivity decreases, which appears to be associated with greater arterial stiffness compared with similarly aged men. The blunted sympathetic baroreflex sensitivity in older women may predispose them to an increased prevalence of hypertension and cardiovascular disease.
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Affiliation(s)
- Qi Fu
- Women's Heart Health Laboratory, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Suite 435, Dallas, TX, 75231, USA.
- The University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Tokyo, Japan
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86
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Hissen SL, Macefield VG, Brown R, Taylor CE. Sympathetic baroreflex sensitivity is inversely related to vascular transduction in men but not women. Am J Physiol Heart Circ Physiol 2019; 317:H1203-H1209. [PMID: 31675259 DOI: 10.1152/ajpheart.00501.2019] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sympathetic baroreflex sensitivity (BRS) is a measure of how effectively the baroreflex buffers beat-to-beat changes in blood pressure through the modulation of muscle sympathetic nerve activity (MSNA). However, current methods of assessment do not take into account the transduction of sympathetic nerve activity at the level of the vasculature, which is known to vary between individuals. In this study we tested the hypothesis that there is an inverse relationship between sympathetic BRS and vascular transduction. In 38 (18 men) healthy adults, continuous measurements of blood pressure, MSNA and superficial femoral artery diameter and blood flow (Doppler ultrasound) were recorded during 10 min of rest. Spontaneous sympathetic BRS was quantified as the relationship between diastolic pressure and MSNA burst incidence. Vascular transduction was quantified by plotting the changes in leg vascular conductance for 10 cardiac cycles following each burst of MSNA, and taking the nadir. In men, sympathetic BRS was inversely related to vascular transduction (r = -0.49; P = 0.04). However, this relationship was not present in women (r = -0.17; P = 0.47). To conclude, an interaction exists between sympathetic BRS and vascular transduction in healthy men, such that men with high sympathetic BRS have low vascular transduction and vice versa. This may be to ensure that blood pressure is regulated effectively, although further research is needed to explore what mechanisms are involved and examine why this relationship was not apparent in women.NEW & NOTEWORTHY Evidence suggests that compensatory interactions exist between factors involved in cardiovascular control. This study was the first to demonstrate an inverse relationship between sympathetic BRS and beat-to-beat vascular transduction. Those with low sympathetic BRS had high vascular transduction and vice versa. However, this interaction was present in young men but not women.
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Affiliation(s)
- Sarah L Hissen
- School of Science and Health, Western Sydney University, Sydney, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia.,Neuroscience Research Australia, Sydney, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Rachael Brown
- School of Medicine, Western Sydney University, Sydney, Australia.,Neuroscience Research Australia, Sydney, Australia
| | - Chloe E Taylor
- School of Science and Health, Western Sydney University, Sydney, Australia.,School of Medicine, Western Sydney University, Sydney, Australia
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87
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Khoo MCK, Chalacheva P. Respiratory modulation of peripheral vasoconstriction: a modeling perspective. J Appl Physiol (1985) 2019; 127:1177-1186. [DOI: 10.1152/japplphysiol.00111.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Although respiratory sinus arrhythmia and blood pressure variability have been investigated extensively, there have been far fewer studies of the respiratory modulation of peripheral blood flow in humans. Existing studies have been based primarily on noninvasive measurements using digit photoplethysmography and laser-Doppler flowmetry. The cumulative knowledge derived from these studies suggests that respiration can contribute to fluctuations in peripheral blood flow and volume through a combination of mechanical, hemodynamic, and neural mechanisms. However, the most convincing evidence suggests that the sympathetic nervous system plays the predominant role under normal, resting conditions. This mini-review provides a consolidation and interpretation of the key findings reported in this topical area. Given the need to extract dynamic information from noninvasive measurements under largely “closed-loop” conditions, we propose that the application of analytical tools based on systems theory and mathematical modeling can be of great utility in future studies. In particular, we present an example of how the transfer relation linking respiration to peripheral vascular conductance can be derived using measurements recorded during spontaneous breathing, spontaneous sighs, and ventilator-induced sighs.
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Affiliation(s)
- Michael C. K. Khoo
- Biomedical Engineering Department, University of Southern California, Los Angeles, California
| | - Patjanaporn Chalacheva
- Biomedical Engineering Department, University of Southern California, Los Angeles, California
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88
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Measurement of compensatory reserve predicts racial differences in tolerance to simulated hemorrhage in women. J Trauma Acute Care Surg 2019; 85:S77-S83. [PMID: 29443858 DOI: 10.1097/ta.0000000000001837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The compensatory reserve measurement (CRM) has been established to accurately measure the body's total integrated capacity to compensate for physiologic states of reduced central blood volume and predict hemodynamic decompensation associated with inadequate tissue oxygenation. We previously demonstrated that African American (AA) women have a higher tolerance to reductions in central blood volume. Therefore, we tested the hypothesis that the CRM would identify racial differences during simulated hemorrhage, before the onset of traditional signs/symptoms. METHODS We performed a retrospective analysis during simulated hemorrhage using lower-body negative pressure (LBNP) in 23 AA (22 ± 1 years; 24 ± 1 kg/m) and 31 white women (WW) (20 ± 1 years; 23 ± 1 kg/m). Beat-by-beat blood pressure (BP) and heart rate (HR) were recorded during progressive lower body negative pressure to presyncope. The BP waveforms were analyzed using a machine-learning algorithm to derive the CRM at each lower body negative pressure stage. RESULTS Resting mean arterial BP (AA, 78 ± 3 mm Hg vs. WW, 74 ± 2 mm Hg) and HR (AA, 68 ± 2 bpm vs. WW, 65 ± 2 bpm) were similar between groups. The CRM progressively decreased during LBNP in both groups; however, the rate of decline in the CRM was less (p < 0.05) in AA. The CRM was 4% higher in AA at -15 mm Hg LBNP and progressively increased to 21% higher at -50 mm Hg LBNP (p < 0.05). However, changes in BP and HR were not different between groups. CONCLUSION These data support the notion that the greater tolerance to simulated hemorrhage induced by LBNP in AA women can be explained by their greater capacity to protect the reserve to compensate for progressive central hypovolemia compared with WW, independent of standard vital signs. LEVEL OF EVIDENCE Diagnostic test, level II.
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89
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Holwerda SW, Luehrs RE, DuBose LE, Majee R, Pierce GL. Sex and age differences in the association between sympathetic outflow and central elastic artery wall thickness in humans. Am J Physiol Heart Circ Physiol 2019; 317:H552-H560. [PMID: 31274352 DOI: 10.1152/ajpheart.00275.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Aging is characterized by increased wall thickness of the central elastic arteries (i.e., aorta and carotid arteries), although the mechanisms involved are unclear. Evidence suggests that age-related increases in muscle sympathetic nerve activity (MSNA) may be a contributing factor. However, studies in humans have been lacking. Therefore, we tested the hypothesis that age-related increases in MSNA would be independently associated with carotid artery intima-media thickness (IMT) but not in young women given the reduced influence of MSNA on the vasculature in this group. In 93 young and middle-age/older (MA/O) adults (19-73 yr, 41 women), we performed assessments of MSNA (microneurography) and common carotid IMT and lumen diameter (ultrasonography). Multiple regression that included MSNA and other cardiovascular disease risk factors indicated that MSNA (P = 0.002) and 24-h systolic blood pressure (BP) (P = 0.024) were independent determinants of carotid IMT-to-lumen ratio (model R2 = 0.38, P < 0.001). However, when examining only young women (<45 yr), no correlation was observed between MSNA and carotid IMT-to-lumen ratio (R = -0.01, P = 0.963). MSNA was significantly correlated with IMT-to-lumen ratio while controlling for 24-h systolic BP among young men (R = 0.49, P < 0.001) and MA/O women (R = 0.59, P = 0.022). However, among MA/O men, controlling for 24-h systolic BP attenuated the association between MSNA and carotid IMT-to-lumen ratio (R = 0.50, P = 0.115). Significant age differences in IMT-to-lumen ratio between young and MA/O men (P = 0.047) and young and MA/O women (P = 0.023) were removed when adjusting for MSNA (men: P = 0.970; women: P = 0.152). These findings demonstrate an association between higher sympathetic outflow and carotid artery wall thickness with a particular exception to young women.NEW & NOTEWORTHY Increased wall thickness of the large elastic arteries serves as a graded marker for cardiovascular disease risk and progression of atherosclerosis. Findings from the present study establish an independent association between higher sympathetic outflow and carotid artery wall thickness in adults with an exception to young women and extend findings from animal models that demonstrate hypertrophy of vascular smooth muscle following chronic sympathetic-adrenergic stimulation.
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Affiliation(s)
- Seth W Holwerda
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa.,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
| | - Rachel E Luehrs
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
| | - Lyndsey E DuBose
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
| | - Rumbidzai Majee
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
| | - Gary L Pierce
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa.,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
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90
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Hydration Status and Cardiovascular Function. Nutrients 2019; 11:nu11081866. [PMID: 31405195 PMCID: PMC6723555 DOI: 10.3390/nu11081866] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/30/2019] [Accepted: 08/08/2019] [Indexed: 02/07/2023] Open
Abstract
Hypohydration, defined as a state of low body water, increases thirst sensations, arginine vasopressin release, and elicits renin–angiotensin–aldosterone system activation to replenish intra- and extra-cellular fluid stores. Hypohydration impairs mental and physical performance, but new evidence suggests hypohydration may also have deleterious effects on cardiovascular health. This is alarming because cardiovascular disease is the leading cause of death in the United States. Observational studies have linked habitual low water intake with increased future risk for adverse cardiovascular events. While it is currently unclear how chronic reductions in water intake may predispose individuals to greater future risk for adverse cardiovascular events, there is evidence that acute hypohydration impairs vascular function and blood pressure (BP) regulation. Specifically, acute hypohydration may reduce endothelial function, increase sympathetic nervous system activity, and worsen orthostatic tolerance. Therefore, the purpose of this review is to present the currently available evidence linking acute hypohydration with altered vascular function and BP regulation.
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91
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Stewart JM, Shaban MA, Fialkoff T, Tuma‐Marcella B, Visintainer P, Terilli C, Medow MS. Mechanisms of tilt-induced vasovagal syncope in healthy volunteers and postural tachycardia syndrome patients without past history of syncope. Physiol Rep 2019; 7:e14148. [PMID: 31250563 PMCID: PMC6597794 DOI: 10.14814/phy2.14148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 05/31/2019] [Indexed: 12/25/2022] Open
Abstract
Upright tilt table testing has been used to test for vasovagal syncope (VVS) but can result in "false positives" in which tilt-induced fainting (tilt+) occurs in the absence of real-world fainting. Tilt+ occurs in healthy volunteers and in patients with postural tachycardia syndrome (POTS) and show enhanced susceptibility to orthostatic hypotension. We hypothesized that the mechanisms for hypotensive susceptibility differs between tilt+ healthy volunteers (Control-Faint (N = 12)), tilt+ POTS patients (POTS-Faint (N = 12)) and a non-fainter control group of (Control-noFaint) (N = 10). Subjects were studied supine and during 70° upright tilt while blood pressure (BP), cardiac output (CO), and systemic vascular resistance (SVR), were measured continuously. Impedance plethysmography estimated regional blood volumes, flows, and vascular resistance. Heart rate was increased while central blood volume was decreased in both Faint groups. CO increased in Control-Faint because of reduced splanchnic vascular resistance; splanchnic pooling was similar to Control-noFaint. Splanchnic blood flow in POTS-Faint decreased and resistance increased similar to Control-noFaint but splanchnic blood volume was markedly increased. Decreased SVR and splanchnic arterial vasoconstriction is the mechanism for faint in Control-Faint. Decreased CO caused by enhanced splanchnic pooling is the mechanism for faint in POTS-Faint. We propose that intrahepatic resistance is increased in POTS-Faint resulting in pooling and that both intrahepatic resistance and splanchnic arterial vasoconstriction are reduced in Control-Faint resulting in increased splanchnic blood flow and reduced splanchnic resistance.
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Affiliation(s)
- Julian M. Stewart
- Departments of Pediatrics and PhysiologyNew York Medical CollegeValhallaNew York
| | - Mohamed A. Shaban
- Departments of Pediatrics and PhysiologyNew York Medical CollegeValhallaNew York
| | - Tyler Fialkoff
- Departments of Pediatrics and PhysiologyNew York Medical CollegeValhallaNew York
| | | | - Paul Visintainer
- Baystate Medical CenterUniversity of Massachusetts School of MedicineSpringfield 01199Massachusetts
| | - Courtney Terilli
- Departments of Pediatrics and PhysiologyNew York Medical CollegeValhallaNew York
| | - Marvin S. Medow
- Departments of Pediatrics and PhysiologyNew York Medical CollegeValhallaNew York
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92
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Buharin VE, Shinohara M. Corticospinal excitability for flexor carpi radialis decreases with baroreceptor unloading during intentional co-contraction with opposing forearm muscles. Exp Brain Res 2019; 237:1947-1958. [PMID: 31129694 DOI: 10.1007/s00221-019-05563-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/17/2019] [Indexed: 11/29/2022]
Abstract
Concurrent activation of antagonistic muscles (co-contraction) is used for stiffening a joint, whereas its neural control under hemodynamic stress (e.g., posture change, high gravity, and hemorrhage) is unknown. Corticospinal excitability during co-contraction may be altered with baroreceptor unloading due to potential modulations in spinal and/or inhibitory pathways (e.g., disynaptic group I inhibition and GABA-mediated intracortical inhibition). The purpose of this study was to understand the effect of baroreceptor unloading on corticospinal excitability during co-contraction in humans. Motor evoked potential and cortical silent period in a wrist flexor muscle were examined using transcranial magnetic stimulation in two groups of healthy young adults. All subjects performed isometric contraction of the wrist flexors (flexion) and co-contraction of the wrist flexors and extensors (co-contraction). Spinal disynaptic inhibition was also assessed with the ratio of H-reflex responses to unconditioned and conditioned electrical stimulations of the peripheral nerves for the muscles. In one of the groups, baroreflex unloading was induced by applying lower body negative pressure. There was no significant effect of baroreflex unloading on cortical silent period or H-reflex measure of disynaptic inhibition. With baroreflex unloading, motor evoked potential area in the flexor carpi radialis was decreased during co-contraction but not during flexion. The results indicated that baroreceptor unloading decreases corticospinal excitability during co-contraction of antagonistic muscles, apparently by influencing neural pathways that were not probed with cortical silent period or spinal disynaptic inhibition.
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Affiliation(s)
- Vasiliy E Buharin
- School of Biological Sciences, Georgia Institute of Technology, 555 14th Street NW, Atlanta, GA, 30332-0356, USA.,Activ Surgical, 840 Summer Street, Suite 108, Boston, MA, 02127, USA
| | - Minoru Shinohara
- School of Biological Sciences, Georgia Institute of Technology, 555 14th Street NW, Atlanta, GA, 30332-0356, USA.
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93
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Witte E, Liu Y, Ward JL, Kempf KS, Whitaker A, Vidoni ED, Craig JC, Poole DC, Billinger SA. Exercise intensity and middle cerebral artery dynamics in humans. Respir Physiol Neurobiol 2019; 262:32-39. [PMID: 30710650 PMCID: PMC6393201 DOI: 10.1016/j.resp.2019.01.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/11/2019] [Accepted: 01/29/2019] [Indexed: 12/24/2022]
Abstract
Despite its necessity for understanding healthy brain aging, the influence of exercise intensity on cerebrovascular kinetics is currently unknown. We, therefore characterized middle cerebral artery blood flow velocity (MCAv) kinetics associated with two exercise intensities: low and moderate. We hypothesized that increasing exercise intensity would increase the MCAv amplitude response (Amp) and that age and estimated fitness (V̇O2max) would be related to Amp. Baseline (BL) values were collected for 90-seconds followed by a 6-minute exercise bout. Heart rate, end-tidal CO2, mean arterial pressure and MCAv were recorded throughout. MCAv kinetics were described by Amp, time delay (TD) and time constant (τ). Sixty-four adults completed the study. Amp was greater during moderate compared to low exercise intensity (p < 0.001) while no difference was observed in either TD (p = 0.65) or τ (p = 0.47). Amp was negatively associated with age (p < 0.01) and positively correlated with estimated V̇O2max (p < 0.01). Although Amp declines with age, maintaining higher V̇O2max may benefit the cerebrovascular response to exercise.
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Affiliation(s)
- Emily Witte
- University of Kansas Medical Center, Physical Therapy and Rehabilitation Science, MS 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, United States
| | - Yumei Liu
- University of Kansas Medical Center, Physical Therapy and Rehabilitation Science, MS 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, United States
| | - Jaimie L Ward
- University of Kansas Medical Center, Physical Therapy and Rehabilitation Science, MS 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, United States
| | - Katie S Kempf
- University of Kansas Medical Center, Physical Therapy and Rehabilitation Science, MS 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, United States
| | - Alicen Whitaker
- University of Kansas Medical Center, Physical Therapy and Rehabilitation Science, MS 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, United States
| | - Eric D Vidoni
- University of Kansas, Alzheimer's Disease Center, KU Clinical Research Center 4350 Shawnee Mission Parkway, MS 6002, Fairway, KS 66205, United States
| | - Jesse C Craig
- Kansas State University, Departments of Kinesiology, 131 Coles Hall, 920 Denison Ave, Manhattan, KS 66506, United States
| | - David C Poole
- Kansas State University, Departments of Kinesiology, 131 Coles Hall, 920 Denison Ave, Manhattan, KS 66506, United States
| | - Sandra A Billinger
- University of Kansas Medical Center, Physical Therapy and Rehabilitation Science, MS 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, United States.
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Favre ME, Serrador JM. Sex differences in cerebral autoregulation are unaffected by menstrual cycle phase in young, healthy women. Am J Physiol Heart Circ Physiol 2019; 316:H920-H933. [DOI: 10.1152/ajpheart.00474.2018] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sex is known to affect the prevalence of conditions such as stroke. However, effects of sex on cerebral blood flow regulation are still not well understood. Critical to this understanding is how fluctuations in hormones across the menstrual cycle affect cerebral autoregulation. We measured autoregulation in the early follicular, late follicular, and midluteal phases during spontaneous and induced blood pressure oscillations in 26 young, healthy individuals (13 women and 13 men, age: 26 ± 4 yr). Men participated three times, ~1–3 wk apart. Beat-by-beat blood pressure, heart rate, end-tidal CO2, and transcranial Doppler ultrasonography of the middle (MCA) and anterior (ACA) cerebral arteries were obtained. We did not find a difference in cerebral autoregulation across the menstrual cycle in women but found significantly improved autoregulation in the MCA and ACA of women compared with men. Women demonstrated significantly lower MCA gain (0.97 ± 0.13 vs. 1.17 ± 0.14%/mmHg, P = 0.001), higher MCA phase (46.1 ± 12.6 vs. 35.8 ± 7.9°, P = 0.019), and higher ACA phase (40.5 ± 10.8 vs 31.5 ± 8.5°, P = 0.040) during repeated squat-to-stand maneuvers. Women also had lower MCA gain (1.50 ± 0.11 vs. 1.72 ± 0.30%/mmHg, P = 0.029) during spontaneous fluctuations in pressure while standing and less of a decrease in MCA flow velocity (−18.7 ± 2.7 vs. −23.2 ± 6.0%, P = 0.014) during sit-to-stand maneuvers. Our results suggest that young women have improved cerebral autoregulation compared with young men regardless of menstrual cycle phase and that autoregulation is relatively robust to acute fluctuations in female sex hormones. NEW & NOTEWORTHY This is the first study to investigate thoroughly the effects of menstrual cycle phase and sex differences in cerebral autoregulation in young, healthy individuals. Cerebral autoregulation was unaffected by menstrual cycle phase during both repeated squat-to-stand and sit-to-stand maneuvers. However, women demonstrated significantly improved cerebral autoregulation in the middle and anterior cerebral arteries, suggesting women were able to maintain cerebral blood flow during changes in blood pressure more efficiently than men.
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Affiliation(s)
- Michelle E. Favre
- Department of Pharmacology, Physiology and Neuroscience; Rutgers Biomedical and Health Sciences, Newark, New Jersey
| | - Jorge M. Serrador
- Department of Pharmacology, Physiology and Neuroscience; Rutgers Biomedical and Health Sciences, Newark, New Jersey
- War-Related Illness and Injury Study Center, Department of Veterans Affairs, East Orange, New Jersey
- Department of Cardiovascular Electronics, National University of Ireland Galway, Galway, Ireland
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95
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Robinson AT, Babcock MC, Watso JC, Brian MS, Migdal KU, Wenner MM, Farquhar WB. Relation between resting sympathetic outflow and vasoconstrictor responses to sympathetic nerve bursts: sex differences in healthy young adults. Am J Physiol Regul Integr Comp Physiol 2019; 316:R463-R471. [PMID: 30794437 DOI: 10.1152/ajpregu.00305.2018] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have demonstrated an inverse relation between resting muscle sympathetic nerve activity (MSNA) and vasoconstrictor responsiveness (i.e., sympathetic transduction), such that those with high resting MSNA have low vascular responsiveness, and vice versa. The purpose of this investigation was to determine whether biological sex influences the balance between resting MSNA and beat-to-beat sympathetic transduction. We measured blood pressure (BP) and MSNA during supine rest in 54 healthy young adults (27 females: 23 ± 4 yr, 107 ± 8/63 ± 8 mmHg; 27 males: 25 ± 3 yr, 115 ± 11/64 ± 7 mmHg; means ± SD). We quantified beat-to-beat fluctuations in mean arterial pressure (MAP, mmHg) and limb vascular conductance (LVC, %) for 10 cardiac cycles after each MSNA burst using signal averaging, an index of sympathetic vascular transduction. In females, there was no correlation between resting MSNA (burst incidence; burst/100 heartbeats) and peak ΔMAP (r = -0.10, P = 0.62) or peak ΔLVC (r = -0.12, P = 0.63). In males, MSNA was related to peak ΔMAP (r = -0.50, P = 0.01) and peak ΔLVC (r = 0.49, P = 0.03); those with higher resting MSNA had blunted increases in MAP and reductions in LVC in response to a burst of MSNA. In a sub-analysis, we performed a median split between high- versus low-MSNA status on ΔMAP and ΔLVC within each sex and found that only males demonstrated a significant difference in ΔMAP and ΔLVC between high- versus low-MSNA groups. These findings support an inverse relation between resting MSNA and sympathetic vascular transduction in males only and advance our understanding on the influence of biological sex on sympathetic nervous system-mediated alterations in beat-to-beat BP regulation.
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Affiliation(s)
- Austin T Robinson
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Matthew C Babcock
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Joseph C Watso
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Michael S Brian
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware.,Department of Health and Human Performance, Plymouth State University , Plymouth, New Hampshire
| | - Kamila U Migdal
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Megan M Wenner
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - William B Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
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96
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Minahan C, O'Neill H, Sikkema N, Joyce S, Larsen B, Sabapathy S. Oral contraceptives augment the exercise pressor reflex during isometric handgrip exercise. Physiol Rep 2019; 6. [PMID: 29512308 PMCID: PMC5840454 DOI: 10.14814/phy2.13629] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 01/22/2018] [Accepted: 01/24/2018] [Indexed: 11/24/2022] Open
Abstract
We sought to determine whether oral contraception alters the gender-related differences observed in the exercise pressor reflex during isometric handgrip exercise. Fifteen men, fifteen normally menstruating women (WomenNM), and fifteen women taking monophasic oral contraceptives (WomenOC) completed two trials of a 3-min isometric handgrip exercise protocol performed at 30% of their maximal voluntary contraction: (1) where arterial occlusion was applied to the previously exercising arm during a 3-min recovery period (Occlusion trial); (2) where no arterial occlusion was applied during recovery (Control trial). Handgrip exercise elicited greater increases in mean arterial pressure (MAP) in MEN compared to both female groups (P < 0.05), and in WomenOC compared to WomenNM in both trials (P = 0.01, P = 0.03). After 3 min of recovery, sBP was 12% (P = 0.01) and 9% (P = 0.02) higher in the Occlusion trial when compared to the Control trial for MEN and WomenOC. Conversely, arterial occlusion in recovery from handgrip did not sustain elevated sBP in the Occlusion trial, and sBP returned to recovery levels not different to the Control trial, in WomenNM (P = 0.41). These data indicate that gender-related differences in the metaboreflex during isometric handgrip exercise exist between men and normally menstruating women, but are blunted when men are compared to women taking oral contraceptives. We conclude that the suppression of 17β-estradiol and/or progestogen in women via the administration of oral contraceptives attenuates sex-related differences in the metaboreflex during isometric handgrip exercise.
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Affiliation(s)
- Clare Minahan
- Griffith Sports Physiology and Performance, Gold Coast, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Hailey O'Neill
- Griffith Sports Physiology and Performance, Gold Coast, Queensland, Australia
| | - Nelie Sikkema
- Griffith Sports Physiology and Performance, Gold Coast, Queensland, Australia
| | - Sarah Joyce
- Griffith Sports Physiology and Performance, Gold Coast, Queensland, Australia
| | - Brianna Larsen
- Griffith Sports Physiology and Performance, Gold Coast, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia.,Queensland Academy of Sport Centre of Excellence for Applied Sport Science Research, Nathan, Queensland, Australia
| | - Surendran Sabapathy
- Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
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97
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Carter JR. Microneurography and sympathetic nerve activity: a decade-by-decade journey across 50 years. J Neurophysiol 2019; 121:1183-1194. [PMID: 30673363 DOI: 10.1152/jn.00570.2018] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The technique of microneurography has advanced the field of neuroscience for the past 50 years. While there have been a number of reviews on microneurography, this paper takes an objective approach to exploring the impact of microneurography studies. Briefly, Web of Science (Thomson Reuters) was used to identify the highest citation articles over the past 50 years, and key findings are presented in a decade-by-decade highlight. This includes the establishment of microneurography in the 1960s, the acceleration of the technique by Gunnar Wallin in the 1970s, the international collaborations of the 1980s and 1990s, and finally the highest impact studies from 2000 to present. This journey through 50 years of microneurographic research related to peripheral sympathetic nerve activity includes a historical context for several of the laboratory interventions commonly used today (e.g., cold pressor test, mental stress, lower body negative pressure, isometric handgrip, etc.) and how these interventions and experimental approaches have advanced our knowledge of cardiovascular, cardiometabolic, and other human diseases and conditions.
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Affiliation(s)
- Jason R Carter
- Department of Kinesiology and Integrative Physiology, Michigan Technological University , Houghton, Michigan
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98
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Mansur DE, Campos MO, Mattos JD, Paiva ACS, Rocha MP, Videira RLR, Macefield VG, Nóbrega ACL, Fernandes IA. Muscle sympathetic nerve activity and hemodynamic responses to venous distension: does sex play a role? Am J Physiol Heart Circ Physiol 2018; 316:H734-H742. [PMID: 30592900 DOI: 10.1152/ajpheart.00702.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peripheral venous distension mechanically stimulates type III/IV sensory fibers in veins and evokes pressor and sympathoexcitatory reflex responses in humans. As young women have reduced venous compliance and impaired sympathetic transduction, we tested the hypothesis that pressor and sympathoexcitatory responses to venous distension may be attenuated in women compared with men. Mean arterial pressure (photoplethysmography), heart rate (HR), stroke volume (SV; Modelflow), cardiac output (CO = HR × SV), muscle sympathetic nerve activity (MSNA), femoral artery blood flow, and femoral artery conductance (Doppler ultrasound) were quantified in eight men (27 ± 4 yr) and nine women (28 ± 4 yr) before [control (CON)], during (INF), and immediately after (post-INF) a local infusion of saline [5% of the total forearm volume (30 ml/min); the infusion time was 2 ± 1 and 1 ± 1 min ( P = 0.0001) for men and women, respectively] through a retrograde catheter inserted into an antecubital vein, to which venous drainage and arterial supply had been occluded. Mean arterial pressure increased during and after infusion in both groups (vs. the CON group, P < 0.05), but women showed a smaller pressor response in the post-INF period (Δ+7.2 ± 2.0 vs. Δ+18.3 ± 3.9 mmHg in men, P = 0.019). MSNA increased and femoral artery conductance decreased similarly in both groups (vs. the CON group, P < 0.05) at post-INF. Although HR changes were similar, increases in SV (Δ+20.4 ± 8.6 vs. Δ+2.6 ± 2.7 ml, P = 0.05) and CO (Δ+0.84 ± 0.17 vs. Δ+0.34 ± 0.10 l/min, P = 0.024) were greater in men compared with women. Therefore, venous distension evokes a smaller pressor response in young women due to attenuated cardiac adjustments rather than reduced venous compliance or sympathetic transduction. NEW & NOTEWORTHY We found that the pressor response to venous distension was attenuated in young women compared with age-matched men. This was due to attenuated cardiac adjustments rather than reduced venous compliance, sympathetic activation, or impaired transduction and vascular control. Collectively, these findings suggest that an attenuated venous distension reflex could be involved in orthostatic intolerance in young women.
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Affiliation(s)
- Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Monique O Campos
- 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
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | | | - Vaughan G Macefield
- College of Medicine, Mohammed Bin Rashid University of Health and Medicine , Dubai , United Arab Emirates.,Baker Heart and Diabetes Institute , Melbourne, Victoria , Australia
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil.,NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasília , Brazil
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99
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El Sayed K, Macefield VG, Hissen SL, Joyner MJ, Taylor CE. Blood pressure reactivity at onset of mental stress determines sympathetic vascular response in young adults. Physiol Rep 2018; 6:e13944. [PMID: 30552755 PMCID: PMC6294720 DOI: 10.14814/phy2.13944] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 11/22/2018] [Indexed: 11/24/2022] Open
Abstract
We have previously shown in young males that the rate of rise in blood pressure (BP) at the onset of mental stress determines whether or not muscle sympathetic nerve activity (MSNA) has a role in driving the pressor response. The aim of this study was to investigate these interactions in young females. BP and MSNA were recorded continuously in 19 females and 21 males during 2-min mental stressors (mental arithmetic and Stroop test). Physical stressor tasks (cold pressor, handgrip exercise, postexercise ischemia) were also performed. During the first minute of mental arithmetic, the rate of rise in mean arterial pressure (MAP) was significantly greater in negative responders (mean decrease in MSNA) compared with positive responders (mean increase in MSNA) in both males (1.9 ± 0.7 vs. 0.7 ± 0.3 mmHg/sec) and females (1.0 ± 0.3 vs. 0.5 ± 0.2 mmHg/sec). For the Stroop test, there was no significant difference in the rate of the rise in BP between positive and negative responders (P > 0.05). However, peak changes in MAP were significantly greater in negative responders compared with positive responders in both males (22 ± 6 vs. 13 ± 3 mmHg) and females (12 ± 2 vs. 6 ± 1 mmHg). Sympathetic baroreflex sensitivity was greater in negative responders and may contribute to the fall in MSNA experienced by these individuals during mental stress. During physical stressors there were consistent increases in BP and MSNA in males and females. The findings suggest that, in both males and females, BP reactivity at the onset of mental stress dictates whether or not there is an increase or decrease in MSNA.
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Affiliation(s)
- Khadigeh El Sayed
- School of MedicineWestern Sydney UniversitySydneyNew South WalesAustralia
| | - Vaughan G. Macefield
- School of MedicineWestern Sydney UniversitySydneyNew South WalesAustralia
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Baker Heart and Diabetes InstituteMelbourneVictoriaAustralia
| | - Sarah L Hissen
- School of Science and HealthWestern Sydney UniversitySydneyNew South WalesAustralia
| | | | - Chloe E. Taylor
- School of MedicineWestern Sydney UniversitySydneyNew South WalesAustralia
- School of Science and HealthWestern Sydney UniversitySydneyNew South WalesAustralia
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100
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Kahkashan N, Arifuddin MS, Hazari MAH, Sultana S, Fatima F, Anees S. Variation in carotid-femoral pulse wave velocity, augmentation pressure and augmentation index during different phases of menstrual cycle. ANNALS OF MEDICAL PHYSIOLOGY 2018; 2:27-32. [DOI: 10.23921/amp.2018v2i3.10454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Physiological variation of estrogen and progesterone during menstrual cycle is well known. They not only have an effect on blood pressure control, but also seem to have a role in regulating arterial compliance. This study was done to find out whether there are any changes in central arterial parameters during different phases of menstrual cycle. Thirty female subjects in the age group of 18-22 years with normal, regular menstrual cycles participated in this prospective observational study at our teaching hospital. Anthropometric parameters were recorded. Blood pressure in all 4 limbs was recorded using cardiovascular risk analyzer-Periscope™ on Day 3rd to 5th (follicular phase), Day 12th to 14th (ovulation phase), Day 22nd to 24th (luteal phase) of their menstrual cycle. We collected blood samples during these three phases for estimation of estradiol and progesterone by ELISA technique. Analysis of variance and correlation statistics were done using SPSS 17.0 statistical software. No significant statistical changes were observed in systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure, aortic systolic pressure, aortic diastolic pressure, aortic augmentation pressure, aortic index and pulse wave velocity during the three recorded phases of the menstrual cycle. There are many studies which correlate changes in peripheral artery blood pressure with different phases of menstrual cycle. But there is scarcity in data available which correlates central arterial pressures and arterial stiffness with natural hormonal variations in different phases of menstrual cycle. However, our results show that although there are subtle changes in blood pressure parameters along with estrogen and progesterone levels throughout the menstrual cycle, yet these were not statistically significant.
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