Schwartz J S, Bache R J
Department of Medicine, University of Minnesota Medical School, Minneapolis.
J Cardiovasc Pharmacol. 1988 May;11(5):608-13. doi: 10.1097/00005344-198805000-00014.
Cardiac glycosides have previously been shown to constrict small coronary resistance vessels. This study evaluated the effect of a bolus intravenous dose of ouabain (20 micrograms/kg) on large left circumflex coronary arterial diameter measured by sonomicrometry in nine awake chronically instrumented dogs. Between 5 and 10 min after ouabain administration external circumflex coronary diameter decreased (3.87 +/- 0.21 to 3.83 +/- 0.21 mm, p less than 0.05). Twenty minutes after ouabain administration, coronary diameter had returned to control. At the time of the peak decrease in coronary diameter, heart rate had decreased (104 +/- 7 to 82 +/- 7 beats/min, p less than 0.05), circumflex coronary blood flow had decreased (45 +/- 7 to 38 +/- 6 ml/min, p less than 0.05), total circumflex coronary resistance had increased (2.7 +/- 0.4 to 3.5 +/- 0.6 U, p less than 0.05) and aortic pressure was unchanged (108 +/- 4 to 113 +/- 4 mm Hg). Alpha-adrenergic blockade with phentolamine did not prevent the decrease in circumflex coronary arterial diameter in each of five dogs (3.67 +/- 0.28 to 3.60 +/- 0.28 mm, p less than 0.05). Therefore, intravenous ouabain caused vasoconstriction of large coronary arteries. These vasocontrictor effects were not mediated by alpha-adrenergic mechanisms. This constriction could have important consequences in the presence of coronary stenoses.
强心苷类药物先前已被证明可使小冠状动脉阻力血管收缩。本研究评估了静脉推注哇巴因（20微克/千克）对9只清醒的、长期植入仪器的犬通过超声测量法测得的左旋支冠状动脉大血管直径的影响。给予哇巴因后5至10分钟，左旋支冠状动脉外径减小（从3.87±0.21毫米降至3.83±0.21毫米，p<0.05）。给予哇巴因20分钟后，冠状动脉直径恢复至对照水平。在冠状动脉直径减小的峰值时刻，心率下降（从104±7次/分钟降至82±7次/分钟，p<0.05），左旋支冠状动脉血流量下降（从45±7毫升/分钟降至38±6毫升/分钟，p<0.05），左旋支冠状动脉总阻力增加（从2.7±0.4单位增至3.5±0.6单位，p<0.05），而主动脉压力未改变（从108±4毫米汞柱增至113±4毫米汞柱）。用酚妥拉明进行α-肾上腺素能阻断并未阻止五只犬中每只犬的左旋支冠状动脉直径减小（从3.67±0.28毫米降至3.60±0.28毫米，p<0.05）。因此，静脉注射哇巴因可导致大冠状动脉血管收缩。这些血管收缩作用并非由α-肾上腺素能机制介导。在存在冠状动脉狭窄的情况下，这种收缩可能会产生重要后果。
