Himori N, Taira N
Naunyn Schmiedebergs Arch Pharmacol. 1976 Jul;294(1):31-7. doi: 10.1007/BF00692782.
In the arterially blood-perfused canine papillary muscle, i.a. injections of dipyridamole (10-300 mug) produced a dose-dependent increase in developed tension amounting to about 45% of the basal developed tension at 300 mug. The positive inotropic response to dipyridamole was greatly reduced by a prior i.a. injection of propranolol (10 mug) or by pretreatment with reserpine (0.2 mg/kg s.c. for 3 consecutive days) but not affected by a prior i.a. injection of tetrodotoxin (1 mug) or desmethylimipramine (3-10 mug). The positive inotropic response to dipyridamole reduced by pretreatment with reserpine was restored by i.a. infusion of noradrenaline (0.03 mug/min). Dipyridamole did not modify the positive inotropic responses to noradrenaline and tyramine. These results suggest that the positive inotropic response to dipyridamole is largely due to noradrenaline released from adrenergic nerve endings by a mechanism that differs from those operative in the action of tyramine or in liberation of noradrenaline upon excitation.
在动脉血灌注的犬乳头肌中，动脉内注射双嘧达莫（10 - 300微克）可使张力增加呈现剂量依赖性，在300微克时增加幅度约为基础张力的45%。预先动脉内注射普萘洛尔（10微克）或用利血平预处理（皮下注射0.2毫克/千克，连续3天）可使双嘧达莫的正性肌力反应大大降低，但预先动脉内注射河豚毒素（1微克）或去甲丙咪嗪（3 - 10微克）则不影响该反应。用利血平预处理后降低的双嘧达莫正性肌力反应，通过动脉内输注去甲肾上腺素（0.03微克/分钟）得以恢复。双嘧达莫并不改变对去甲肾上腺素和酪胺的正性肌力反应。这些结果表明，双嘧达莫的正性肌力反应很大程度上是由于去甲肾上腺素从肾上腺素能神经末梢释放，其机制不同于酪胺作用或兴奋时去甲肾上腺素释放所涉及的机制。
