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Metabolite accumulation augments muscle mechanoreflex influence on carotid baroreflex control of heart rate but not blood pressure in man
Author(s) -
Drew Rachel,
White Michael
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.lb121
Subject(s) - baroreflex , isometric exercise , circulatory system , blood pressure , heart rate , mean arterial pressure , medicine , cardiology , reflex , occlusion , anesthesia
The influence of muscle mechanoreflex activation on carotid baroreflex (CBR) control of mean arterial pressure (MAP) and heart rate (HR) was investigated during post‐exercise circulatory occlusion (PECO) and concurrent passive calf stretch of the exercised or contralateral limb. In 4 trials, with local circulatory occlusion, subjects either sustained one‐legged isometric calf plantarflexor exercise at 50% maximum force for 1.5 min (EX) or rested (CON). Occlusion continued for a further 6.5min, in the last 3min of which concurrent sustained passive stretch of the previously exercised calf (PE) or previously inactive calf (PI) occurred for EX and CON. CBR function was determined in each phase using rapid pulses of neck pressure from +40 to −80mmHg. PECO produced an upward and rightward shift of the CBR‐MAP and CBR‐HR function curves compared to CON and concurrent stretch in PI did not alter maximum CBR‐HR gain from CON. Passive stretch in PE decreased the maximum CBR‐HR gain compared to PI and CON without further resetting. Maximum CBR‐MAP gain was unaffected by stretch in PI or PE but there was further rightward and upward resetting of the function curves from PECO. These findings indicate that exercise‐induced metabolite accumulation augments mechanoreflex activation during stretch, suggesting sensitization of mechanoreceptors which leads to increased cardiac vagal inhibition.