Dynamic exercise training prevents exercise pressor reflex overactivity in spontaneously hypertensive rats

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5 Citations (Scopus)

Abstract

Cardiovascular responses to exercise are exaggerated in hypertension. We previously demonstrated that this heightened cardiovascular response to exercise is mediated by an abnormal skeletal muscle exercise pressor reflex (EPR) with important contributions from its mechanically and chemically sensitive components. Exercise training attenuates exercise pressor reflex function in healthy subjects as well as in heart failure rats. However, whether exercise training has similar physiological benefits in hypertension remains to be elucidated. Thus we tested the hypothesis that the EPR overactivity manifest in hypertension is mitigated by exercise training. Changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to muscle contraction, passive muscle stretch, and hindlimb intra-arterial capsaicin administration were examined in untrained normotensive Wistar-Kyoto rats (WKY<inf>UT</inf>; n=6), exercise-trained WKY (WKY<inf>ET</inf>; n =7), untrained spontaneously hypertensive rats (SHRUT; n=8), and exercise-trained SHR (SHR<inf>ET</inf>; n =7). Baseline MAP after decerebration was significantly decreased by 3 mo of wheel running in SHR<inf>ET</inf> (104 ± 9 mmHg) compared with SHRUT (125 ± 10 mmHg). As previously reported, the pressor and renal sympathetic responses to muscle contraction, stretch, and capsaicin administration were significantly higher in SHR<inf>UT</inf> than WKY<inf>UT</inf>. Exercise training significantly attenuated the enhanced contraction-induced elevations in MAP (SHR<inf>UT</inf>: 53 ±11 mmHg; SH<inf>RET</inf>: 19 ± 3 mmHg) and RSNA (SHRUT: 145 ± 32%; SHRET: 57 ± 11%). Training produced similar attenuating effects in SHR during passive stretch and capsaicin administration. These data demonstrate that the abnormally exaggerated EPR function that develops in hypertensive rats is significantly diminished by exercise training.

Original languageEnglish (US)
Pages (from-to)H762-H770
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume309
Issue number5
DOIs
StatePublished - Sep 3 2015

Fingerprint

Inbred SHR Rats
Reflex
Exercise
Capsaicin
Arterial Pressure
Muscle Contraction
Hypertension
Kidney
Inbred WKY Rats
Hindlimb
Running
Healthy Volunteers
Skeletal Muscle
Heart Failure

Keywords

  • Blood pressure
  • Exercise pressor reflex
  • Hypertension exercise training
  • Sympathetic nerve activity

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Cardiology and Cardiovascular Medicine

Cite this

@article{c022ccb0e77a47db8b4c9512b2bbd61a,
title = "Dynamic exercise training prevents exercise pressor reflex overactivity in spontaneously hypertensive rats",
abstract = "Cardiovascular responses to exercise are exaggerated in hypertension. We previously demonstrated that this heightened cardiovascular response to exercise is mediated by an abnormal skeletal muscle exercise pressor reflex (EPR) with important contributions from its mechanically and chemically sensitive components. Exercise training attenuates exercise pressor reflex function in healthy subjects as well as in heart failure rats. However, whether exercise training has similar physiological benefits in hypertension remains to be elucidated. Thus we tested the hypothesis that the EPR overactivity manifest in hypertension is mitigated by exercise training. Changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to muscle contraction, passive muscle stretch, and hindlimb intra-arterial capsaicin administration were examined in untrained normotensive Wistar-Kyoto rats (WKYUT; n=6), exercise-trained WKY (WKYET; n =7), untrained spontaneously hypertensive rats (SHRUT; n=8), and exercise-trained SHR (SHRET; n =7). Baseline MAP after decerebration was significantly decreased by 3 mo of wheel running in SHRET (104 ± 9 mmHg) compared with SHRUT (125 ± 10 mmHg). As previously reported, the pressor and renal sympathetic responses to muscle contraction, stretch, and capsaicin administration were significantly higher in SHRUT than WKYUT. Exercise training significantly attenuated the enhanced contraction-induced elevations in MAP (SHRUT: 53 ±11 mmHg; SHRET: 19 ± 3 mmHg) and RSNA (SHRUT: 145 ± 32{\%}; SHRET: 57 ± 11{\%}). Training produced similar attenuating effects in SHR during passive stretch and capsaicin administration. These data demonstrate that the abnormally exaggerated EPR function that develops in hypertensive rats is significantly diminished by exercise training.",
keywords = "Blood pressure, Exercise pressor reflex, Hypertension exercise training, Sympathetic nerve activity",
author = "Masaki Mizuno and Iwamoto, {Gary A.} and Wanpen Vongpatanasin and Mitchel, {Jere H.} and Smith, {Scott A.}",
year = "2015",
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T1 - Dynamic exercise training prevents exercise pressor reflex overactivity in spontaneously hypertensive rats

AU - Mizuno, Masaki

AU - Iwamoto, Gary A.

AU - Vongpatanasin, Wanpen

AU - Mitchel, Jere H.

AU - Smith, Scott A.

PY - 2015/9/3

Y1 - 2015/9/3

N2 - Cardiovascular responses to exercise are exaggerated in hypertension. We previously demonstrated that this heightened cardiovascular response to exercise is mediated by an abnormal skeletal muscle exercise pressor reflex (EPR) with important contributions from its mechanically and chemically sensitive components. Exercise training attenuates exercise pressor reflex function in healthy subjects as well as in heart failure rats. However, whether exercise training has similar physiological benefits in hypertension remains to be elucidated. Thus we tested the hypothesis that the EPR overactivity manifest in hypertension is mitigated by exercise training. Changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to muscle contraction, passive muscle stretch, and hindlimb intra-arterial capsaicin administration were examined in untrained normotensive Wistar-Kyoto rats (WKYUT; n=6), exercise-trained WKY (WKYET; n =7), untrained spontaneously hypertensive rats (SHRUT; n=8), and exercise-trained SHR (SHRET; n =7). Baseline MAP after decerebration was significantly decreased by 3 mo of wheel running in SHRET (104 ± 9 mmHg) compared with SHRUT (125 ± 10 mmHg). As previously reported, the pressor and renal sympathetic responses to muscle contraction, stretch, and capsaicin administration were significantly higher in SHRUT than WKYUT. Exercise training significantly attenuated the enhanced contraction-induced elevations in MAP (SHRUT: 53 ±11 mmHg; SHRET: 19 ± 3 mmHg) and RSNA (SHRUT: 145 ± 32%; SHRET: 57 ± 11%). Training produced similar attenuating effects in SHR during passive stretch and capsaicin administration. These data demonstrate that the abnormally exaggerated EPR function that develops in hypertensive rats is significantly diminished by exercise training.

AB - Cardiovascular responses to exercise are exaggerated in hypertension. We previously demonstrated that this heightened cardiovascular response to exercise is mediated by an abnormal skeletal muscle exercise pressor reflex (EPR) with important contributions from its mechanically and chemically sensitive components. Exercise training attenuates exercise pressor reflex function in healthy subjects as well as in heart failure rats. However, whether exercise training has similar physiological benefits in hypertension remains to be elucidated. Thus we tested the hypothesis that the EPR overactivity manifest in hypertension is mitigated by exercise training. Changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to muscle contraction, passive muscle stretch, and hindlimb intra-arterial capsaicin administration were examined in untrained normotensive Wistar-Kyoto rats (WKYUT; n=6), exercise-trained WKY (WKYET; n =7), untrained spontaneously hypertensive rats (SHRUT; n=8), and exercise-trained SHR (SHRET; n =7). Baseline MAP after decerebration was significantly decreased by 3 mo of wheel running in SHRET (104 ± 9 mmHg) compared with SHRUT (125 ± 10 mmHg). As previously reported, the pressor and renal sympathetic responses to muscle contraction, stretch, and capsaicin administration were significantly higher in SHRUT than WKYUT. Exercise training significantly attenuated the enhanced contraction-induced elevations in MAP (SHRUT: 53 ±11 mmHg; SHRET: 19 ± 3 mmHg) and RSNA (SHRUT: 145 ± 32%; SHRET: 57 ± 11%). Training produced similar attenuating effects in SHR during passive stretch and capsaicin administration. These data demonstrate that the abnormally exaggerated EPR function that develops in hypertensive rats is significantly diminished by exercise training.

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KW - Hypertension exercise training

KW - Sympathetic nerve activity

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