Alpha-adrenergic vascular responsiveness during postexercise XXXX in @entity1 .

@entity1 @entity2647 @entity1338 @entity551 @entity6927
In sedentary individuals, postexercise @entity551 following a single bout of aerobic exercise is due to an unexplained peripheral vasodilatation. We tested the hypothesis that alpha-adrenergic responsiveness in the forearm and leg vasculatures is blunted during postexercise @entity551 . We studied 12 @entity1 and two @entity1 before and 30 min after a 60 min bout of cycling at 60 % VO2,peak. In the first five subjects, arterial pressure (brachial artery catheter) and forearm blood flow (plethysmography) were measured and vascular conductance was calculated during intraarterial infusions of the @entity6927 -agonist @entity2647 and the alpha2-agonist @entity1338 . Exercise reduced mean arterial pressure (89 +/- 2 vs. 95 +/- 2 mmHg, P < 0.05) and increased forearm vascular conductance 77 +/- 33 % (P < 0.05). Despite these changes in baseline vascular conductance, vasoconstrictor responses in the forearm to @entity2647 and @entity1338 were similar (or enhanced) postexercise vs. preexercise. In the remaining nine subjects, arterial pressure (femoral artery catheter) and leg blood flow (Doppler ultrasound of the femoral artery) were measured and vascular conductance was calculated during intraarterial infusions of @entity2647 and @entity1338 . Exercise reduced mean arterial pressure (80 +/- 2 vs. 89 +/- 2 mmHg, P < 0.05) and increased leg vascular conductance 94 +/- 16 % (P < 0.05). Despite these changes in baseline vascular conductance, vasoconstrictor responses in the leg to @entity2647 and @entity1338 were similar (or enhanced) postexercise vs. preexercise. These results suggest that vascular responsiveness to alpha-adrenergic agonists is maintained during postexercise @entity551 in @entity1 . Thus, while postexercise @entity551 is associated with increased vascular conductance in the forearm and leg, it does not appear that blunting of alpha-adrenergic responsiveness is the cause.
