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D'Souza AW, Hissen SL, Manabe K, Takeda R, Washio T, Coombs GB, Sanchez B, Fu Q, Shoemaker JK. Age- and sex-related differences in sympathetic vascular transduction and neurohemodynamic balance in humans. Am J Physiol Heart Circ Physiol 2023; 325:H917-H932. [PMID: 37594483 DOI: 10.1152/ajpheart.00301.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/19/2023]
Abstract
Bursts of muscle sympathetic nerve activity (MSNA) and the ensuing vasoconstriction are pivotal determinants of beat-by-beat blood pressure regulation. Although age and sex impact blood pressure regulation, how these factors affect the central and peripheral arcs of the baroreflex remains unclear. In 27 young [25 (SD 3) yr] males (YM; n = 14) and females (YF; n = 13) and 23 older [71 (SD 5) yr] males (OM; n = 11) and females (OF; n = 12), femoral artery blood flow, blood pressure, and MSNA were recorded for 10 min of supine rest. Sympathetic baroreflex sensitivity (i.e., central arc) was quantified as the relationship between diastolic blood pressure and MSNA burst incidence. Signal averaging was used to determine sympathetic vascular transduction into leg vascular conductance (LVC) for 12 cardiac cycles following MSNA bursts (i.e., peripheral arc). Older adults demonstrated attenuated sympathetic transduction into LVC (both P < 0.001) following MSNA bursts, and smaller increases in sympathetic transduction as a function of MSNA burst size and firing pattern compared with young adults (range, P = 0.004-0.032). YM (r2 = 0.36; P = 0.032) and OM (r2 = 0.51; P = 0.014) exhibited an inverse relationship between the central and peripheral arcs of the baroreflex, whereas females did not (YF, r2 = 0.03, P = 0.621; OF, r2 = 0.06, P = 0.445). MSNA burst incidence was inversely related to sympathetic transduction in YM and OF (range, P = 0.03-0.046) but not in YF or OM (range, P = 0.360-0.603). These data indicate that age is associated with attenuated sympathetic vascular transduction, whereas age- and sex-specific changes are present in the relationship between the central and peripheral arcs of the baroreflex regulation of blood pressure.NEW & NOTEWORTHY Sympathetic vascular transduction is attenuated in older compared with young adults, regardless of biological sex. Males, but not females (regardless of age), demonstrate an inverse relationship between central (sympathetic baroreflex sensitivity) and peripheral (sympathetic vascular transduction) components of the baroreflex arc. Young males and older females exhibit an inverse relationship between resting sympathetic outflow and sympathetic vascular transduction. Our results indicate that age and sex exert independent and interactive effects on sympathetic vascular transduction and sympathetic neurohemodynamic balance in humans.
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Affiliation(s)
- Andrew W D'Souza
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Sarah L Hissen
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Kazumasa Manabe
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Ryosuke Takeda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan
| | - Takuro Washio
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Geoff B Coombs
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Belinda Sanchez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - J Kevin Shoemaker
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
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DeLorey DS. Sympathetic vasoconstriction in skeletal muscle: Modulatory effects of aging, exercise training, and sex. Appl Physiol Nutr Metab 2021; 46:1437-1447. [PMID: 34348066 DOI: 10.1139/apnm-2021-0399] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sympathetic nervous system (SNS) is a critically important regulator of the cardiovascular system. The SNS controls cardiac output and its distribution, as well as peripheral vascular resistance and blood pressure at rest and during exercise. Aging is associated with increased blood pressure and decreased skeletal muscle blood flow at rest and in response to exercise. The mechanisms responsible for the blunted skeletal muscle blood flow response to dynamic exercise with aging have not been fully elucidated; however, increased muscle sympathetic nerve activity (MSNA), elevated vascular resistance and a decline in endothelium-dependent vasodilation are commonly reported in older adults. In contrast to aging, exercise training has been shown to reduce blood pressure and enhance skeletal muscle vascular function. Exercise training has been shown to enhance nitric oxide-dependent vascular function and may improve the vasodilatory capacity of the skeletal muscle vasculature; however, surprisingly little is known about the effect of exercise training on the neural control of circulation. The control of blood pressure and skeletal muscle blood flow also differs between males and females. Blood pressure and MSNA appear to be lower in young females compared to males. However, females experience a larger increase in MSNA with aging compared to males. The mechanism(s) for the altered SNS control of vascular function in females remain to be determined. Novelty: • This review will summarize our current understanding of the effects of aging, exercise training and sex on sympathetic vasoconstriction at rest and during exercise. • Areas where additional research is needed are also identified.
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Affiliation(s)
- Darren S DeLorey
- University of Alberta, Faculty of Kinesiology, Sport, and Recreation, Edmonton, Alberta, Canada;
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Mueller PJ, Clifford PS, Crandall CG, Smith SA, Fadel PJ. Integration of Central and Peripheral Regulation of the Circulation during Exercise: Acute and Chronic Adaptations. Compr Physiol 2017; 8:103-151. [DOI: 10.1002/cphy.c160040] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Just TP, DeLorey DS. Exercise training and α1-adrenoreceptor-mediated sympathetic vasoconstriction in resting and contracting skeletal muscle. Physiol Rep 2016; 4:4/3/e12707. [PMID: 26869686 PMCID: PMC4758927 DOI: 10.14814/phy2.12707] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Exercise training (ET) increases sympathetic vasoconstrictor responsiveness and enhances contraction‐mediated inhibition of sympathetic vasoconstriction (i.e., sympatholysis) through a nitric oxide (NO)‐dependent mechanism. Changes in α2‐adrenoreceptor vasoconstriction mediate a portion of these training adaptations, however the contribution of other postsynaptic receptors remains to be determined. Therefore, the purpose of this study was to investigate the effect of ET on α1‐adrenoreceptor‐mediated vasoconstriction in resting and contracting muscle. It was hypothesized that α1‐adrenoreceptor‐mediated sympatholysis would be enhanced following ET. Male Sprague Dawley rats were randomized to sedentary (S; n = 12) or heavy‐intensity treadmill ET (n = 11) groups. Subsequently, rats were anesthetized and instrumented for lumbar sympathetic chain stimulation and measurement of femoral vascular conductance (FVC) at rest and during muscle contraction. The percentage change in FVC in response to sympathetic stimulation was measured in control, α1‐adrenoreceptor blockade (Prazosin; 20 μg, IV), and combined α1 and NO synthase (NOS) blockade (l‐NAME; 5 mg·kg−1IV) conditions. Sympathetic vasoconstrictor responsiveness was increased (P < 0.05) in ET compared to S rats at low, but not high (P > 0.05) stimulation frequencies at rest (S: 2 Hz: −25 ± 4%; 5 Hz: −45 ± 5 %; ET: 2 Hz: −35 ± 7%, 5 Hz: −52 ± 7%), whereas sympathetic vasoconstrictor responsiveness was not different (P > 0.05) between groups during contraction (S: 2 Hz: −11 ± 8%; 5 Hz: −26 ± 11%; ET: 2 Hz: −10 ± 7%, 5 Hz: −27 ± 12%). Prazosin blunted (P < 0.05) vasoconstrictor responsiveness in S and ET rats at rest and during contraction, and abolished group differences in vasoconstrictor responsiveness. Subsequent NOS blockade increased vasoconstrictor responses (P < 0.05) in S at rest and during contraction, whereas in ET vasoconstriction was increased (P < 0.05) in response to sympathetic stimulation at 2 Hz at rest and unchanged (P > 0.05) during contraction. ET enhanced (P < 0.05) sympatholysis, however the training‐mediated improvements in sympatholysis were abolished by α1‐adrenoreceptor blockade. Subsequent NOS inhibition did not alter (P > 0.05) sympatholysis in S or ET rats. In conclusion, ET augmented α1‐adrenoreceptor‐mediated vasoconstriction in resting skeletal muscle and enhanced α1‐adrenoreceptor‐mediated sympatholysis. Furthermore, these data suggest that NO is not required to inhibit α2‐adrenoreceptor‐ and nonadrenoreceptor‐mediated vasoconstriction during exercise.
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Affiliation(s)
- Timothy P Just
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Darren S DeLorey
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB, Canada
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Grisé KN, Olver TD, McDonald MW, Dey A, Jiang M, Lacefield JC, Shoemaker JK, Noble EG, Melling CWJ. High Intensity Aerobic Exercise Training Improves Deficits of Cardiovascular Autonomic Function in a Rat Model of Type 1 Diabetes Mellitus with Moderate Hyperglycemia. J Diabetes Res 2016; 2016:8164518. [PMID: 26885531 PMCID: PMC4739461 DOI: 10.1155/2016/8164518] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 02/07/2023] Open
Abstract
Indices of cardiovascular autonomic neuropathy (CAN) in experimental models of Type 1 diabetes mellitus (T1DM) are often contrary to clinical data. Here, we investigated whether a relatable insulin-treated model of T1DM would induce deficits in cardiovascular (CV) autonomic function more reflective of clinical results and if exercise training could prevent those deficits. Sixty-four rats were divided into four groups: sedentary control (C), sedentary T1DM (D), control exercise (CX), or T1DM exercise (DX). Diabetes was induced via multiple low-dose injections of streptozotocin and blood glucose was maintained at moderate hyperglycemia (9-17 mM) through insulin supplementation. Exercise training consisted of daily treadmill running for 10 weeks. Compared to C, D had blunted baroreflex sensitivity, increased vascular sympathetic tone, increased serum neuropeptide Y (NPY), and decreased intrinsic heart rate. In contrast, DX differed from D in all measures of CAN (except NPY), including heart rate variability. These findings demonstrate that this T1DM model elicits deficits and exercise-mediated improvements to CV autonomic function which are reflective of clinical T1DM.
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Affiliation(s)
- Kenneth N. Grisé
- Exercise Biochemistry Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
| | - T. Dylan Olver
- Neurovascular Research Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
| | - Matthew W. McDonald
- Exercise Biochemistry Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
| | - Adwitia Dey
- Exercise Biochemistry Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
| | - Mao Jiang
- Exercise Biochemistry Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
| | - James C. Lacefield
- Department of Electrical and Computer Engineering, Department of Medical Biophysics and Robarts Research Institute, Western University, London, ON, Canada N6A 3K7
| | - J. Kevin Shoemaker
- Neurovascular Research Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
- Department of Physiology and Pharmacology, Western University, London, ON, Canada N6A 3K7
- Lawson Health Research Institute, London, ON, Canada N6C 2R5
| | - Earl G. Noble
- Exercise Biochemistry Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
- Lawson Health Research Institute, London, ON, Canada N6C 2R5
| | - C. W. James Melling
- Exercise Biochemistry Laboratory, School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada N6A 3K7
- *C. W. James Melling:
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Nyberg M, Al-Khazraji BK, Mortensen SP, Jackson DN, Ellis CG, Hellsten Y. Effect of extraluminal ATP application on vascular tone and blood flow in skeletal muscle: implications for exercise hyperemia. Am J Physiol Regul Integr Comp Physiol 2013; 305:R281-90. [PMID: 23761642 DOI: 10.1152/ajpregu.00189.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
During skeletal muscle contractions, the concentration of ATP increases in muscle interstitial fluid as measured by microdialysis probes. This increase is associated with the magnitude of blood flow, suggesting that interstitial ATP may be important for contraction-induced vasodilation. However, interstitial ATP has solely been described to induce vasoconstriction in skeletal muscle. To examine whether interstitial ATP induces vasodilation in skeletal muscle and to what extent this vasoactive effect is mediated by formation of nitric oxide (NO) and prostanoids, three different experimental models were studied. The rat gluteus maximus skeletal muscle model was used to study changes in local skeletal muscle hemodynamics. Superfused ATP at concentrations found during muscle contractions (1-10 μM) increased blood flow by up to 400%. In this model, the underlying mechanism was also examined by inhibition of NO and prostanoid formation. Inhibition of these systems abolished the vasodilator effect of ATP. Cell-culture experiments verified ATP-induced formation of NO and prostacyclin in rat skeletal muscle microvascular endothelial cells, and ATP-induced formation of NO in rat skeletal muscle cells. To confirm these findings in humans, ATP was infused into skeletal muscle interstitium of healthy subjects via microdialysis probes and found to increase muscle interstitial concentrations of NO and prostacyclin by ~60% and ~40%, respectively. Collectively, these data suggest that a physiologically relevant elevation in interstitial ATP concentrations increases muscle blood flow, indicating that the contraction-induced increase in skeletal muscle interstitial [ATP] is important for exercise hyperemia. The vasodilator effect of ATP application is mediated by NO and prostanoid formation.
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Affiliation(s)
- Michael Nyberg
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.
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Jendzjowsky NG, DeLorey DS. Short-term exercise training augments sympathetic vasoconstrictor responsiveness and endothelium-dependent vasodilation in resting skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2012; 303:R332-9. [DOI: 10.1152/ajpregu.00053.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypotheses that 4 wk of exercise training would diminish the magnitude of vasoconstriction in response to sympathetic nerve stimulation and augment endothelium-dependent vasodilation (EDD) in resting skeletal muscle in a training intensity-dependent manner. Sprague-Dawley rats were randomly assigned to sedentary time-control (S), mild- (M; 20 m/min, 5% grade), or heavy-intensity (H; 40 m/min, 5% grade) treadmill exercise groups. Animals trained 5 days/wk for 4 wk with training volume matched between groups. Rats were anesthetized and instrumented for study 24 h after the last training session. Arterial pressure and femoral artery blood flow were measured, and femoral vascular conductance (FVC) was calculated. Lumbar sympathetic chain stimulation was delivered continuously at 2 Hz and in patterns at 20 and 40 Hz. EDD was assessed by the vascular response to intra-arterial bolus injections of ACh. The response (% change FVC) to sympathetic stimulation increased ( P < 0.05) in a training intensity-dependent manner at 2 Hz (S: −20.2 ± 9.8%, M: −34.0 ± 6.7%, and H: −44.9 ± 2.0%), 20 Hz (S: −22.0 ± 10.6%, M: −31.2 ± 8.4%, and H: −42.8 ± 5.9%), and 40 Hz (S: H −24.5 ± 8.5%, M: −35.1 ± 8.9%, H: −44.9 ± 6.5%). The magnitude of EDD also increased in a training intensity-dependent manner ( P < 0.05). These data demonstrate that short-term exercise training augments the magnitude of vasoconstriction in response to sympathetic stimulation and EDD in resting skeletal muscle in a training intensity-dependent manner.
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Affiliation(s)
- Nicholas G. Jendzjowsky
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada; and
| | - Darren S. DeLorey
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada; and
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
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Delorey DS, Clifford PS, Mittelstadt S, Anton MM, Kluess HA, Tune JD, Dincer UD, Buckwalter JB. The effect of aging on adrenergic and nonadrenergic receptor expression and responsiveness in canine skeletal muscle. J Appl Physiol (1985) 2011; 112:841-8. [PMID: 22194325 DOI: 10.1152/japplphysiol.00945.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that adrenergic and nonadrenergic receptor responsiveness and protein expression would be altered with advancing age. Young (n = 6; 22 ± 1 mo; mean ± SE) and old (n = 6; 118 ± 9 mo) beagles were instrumented with flow probes and an indwelling catheter for continuous measurement of external iliac blood flow and arterial blood pressure. Vascular conductance (VC) was calculated as hindlimb blood flow/mean arterial pressure. Selective agonists for α-1, α-2, neuropeptide-Y (NPY), and purinergic (P2X) receptors were infused at rest and during treadmill running at moderate (2.5 mph) and heavy (4 mph with 2.5% grade) exercise intensities. Feed arteries were dissected from gracilis muscles, and α-1D, α-1B, α-2A, P2X-4, P2X-1, and NPY-Y1 receptor protein expression was determined. Phenylephrine produced similar decreases (P > 0.05) in VC in young and old beagles at rest (young: -62 ± 5%; old: -59 ± 5%) and during moderate (young: -67 ± 5%; old: -62 ± 4%) and heavy (young: -54 ± 4%; old: -49 ± 3%) exercise. Clonidine caused similar (P > 0.05) decreases in VC in old compared with young dogs at rest (young: -59 ± 8%; old: -70 ± 6%) and during moderate (young: -52 ± 6%; old: -47 ± 5%)- and heavy (young: -42 ± 5%; old: -43 ± 5%)-intensity exercise. NPY infusion resulted in a similar decline in VC in young and old beagles at rest (young: -40 ± 7%; old: -39 ± 9%) and during moderate (young: -47 ± 6%; old: -40 ± 6%)- and heavy (young: -40 ± 3%; old: -38 ± 4%)-intensity exercise. α-β-Methylene-ATP also produced similar decreases in VC in young and old beagles at rest (young: -36 ± 6%; old: -40 ± 8%) and during exercise at moderate (young: -42 ± 5%; old: -40 ± 9%) and heavy (young: -47 ± 5%; old: -42 ± 8%) intensities. α-1B receptor protein expression was elevated (P < 0.05) in old compared with young dogs, whereas there were no age-related differences in α-1D or α-2A receptor expression and nonadrenergic P2X-4, P2X-1, and NPY-Y1 receptor expression. The present findings indicate that postsynaptic adrenergic and nonadrenergic receptor responsiveness was not altered by advancing age. Moreover, the expression of adrenergic and nonadrenergic receptors in skeletal-muscle feed arteries was largely unaffected by aging.
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Affiliation(s)
- D S Delorey
- Department of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
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