Klabunde R E
Am J Physiol. 1986 Jan;250(1 Pt 2):H62-7. doi: 10.1152/ajpheart.1986.250.1.H62.
The effects of dipyridamole on active hyperemia were evaluated in dog gracilis muscles undergoing sustained isometric contractions. Muscles were stimulated to contract for 5, 15, 25, and 50 s at 20% maximal tension (20% Tmax) or for 10 s at 100% Tmax during intra-arterial infusion of either saline or dipyridamole (1 microM). In two separate groups of dogs, muscles were stimulated to contract under free-flow or restricted-flow (ischemic) conditions. In the later group, blood flow was reduced to 50% of precontraction level during the period of contraction. Dipyridamole increased resting vascular conductance by about 45%; however, it did not affect the change in vascular conductance resulting from muscle contraction. The recovery time for active hyperemia following free-flow contractions at 20% Tmax was not altered by dipyridamole. However, dipyridamole increased the recovery time following 50 s of restricted-flow contraction (20% Tmax) and 10 s of 100% Tmax contractions by 46 and 169%, respectively. These results suggest that adenosine contributes to active hyperemia following sustained ischemic contractions at 20% Tmax and contractions at 100% Tmax but not from contractions at 20% Tmax where blood flow is allowed to increase freely.
在经历持续等长收缩的犬股薄肌中评估双嘧达莫对主动充血的影响。在动脉内输注生理盐水或双嘧达莫（1微摩尔）期间，肌肉以最大张力的20%（20%Tmax）刺激收缩5、15、25和50秒，或以最大张力的100%刺激收缩10秒。在两组不同的犬中，肌肉在自由血流或受限血流（缺血）条件下被刺激收缩。在后者组中，收缩期间血流减少至收缩前水平的50%。双嘧达莫使静息血管传导率增加约45%；然而，它不影响肌肉收缩引起的血管传导率变化。双嘧达莫不改变在20%Tmax自由血流收缩后主动充血的恢复时间。然而，双嘧达莫使在20%Tmax受限血流收缩50秒和100%Tmax收缩10秒后的恢复时间分别增加46%和169%。这些结果表明，腺苷在20%Tmax持续缺血收缩和100%Tmax收缩后对主动充血有作用，但在血流可自由增加的20%Tmax收缩后则不然。
