Oscillatory blood pressure response to the onset of cycling exercise in men: role of group III/IV muscle afferents

摘要: New Findings What is the central question of this study? Neural feedback from group III/IV muscle afferents has a key role in regulation cardiovascular responses to exercise. Blood pressure oscillates first seconds dynamic exercise, but contribution afferent pattern unclear. What main finding and its importance? We demonstrate that attenuation by spinal fentanyl impairs pressor response after 10 s moderate leg cycling does not appear be necessary for induction oscillatory blood at onset exercise. We investigated whether projections skeletal via lumbar intrathecal administration μ-opioid receptor agonist affects (BP) Eight healthy, recreationally active men (28 ± 3 years old) performed 40 s 80 W (60 r.p.m.) before (control) administration, while heart rate, stroke volume, cardiac output, systolic, mean diastolic BP total vascular conductance were continuously monitored. Sytolic included an initial increase (from 0 3 s), followed transient decrease below resting levels 3 10 s) then sustained (>10 s). In presence fentanyl, systolic closely matched those control conditions 10 s, blunted thereafter (P   0.05). These findings suggest during exercise contribute ∼10 s, they do implicated oscillation