Effect of alpha-adrenergic blockade with prazosin on large coronary diameter during exercise.
Effect of alpha-adrenergic blockade with prazosin on large coronary diameter during exercise.
复制标题
哌唑嗪α-肾上腺素能阻断对运动期间大冠状动脉直径的影响。
DOI：
10.1161/01.cir.85.3.1139
复制
发表时间：
1992
期刊：
影响因子：
37.8
通讯作者：
Schwartz,JS
中科院分区：
文献类型：
--
作者：
Baran,KW;Bache,RJ;Dai,XZ;Schwartz,JS
手术诱导的冠状动脉阻力血管扩张受到α-肾上腺素能机制的限制。然而，α-肾上腺素能机制对大冠状动脉在exercise.METHODS和APARTISIn本研究中，sonomicrometry的影响被用来测量回旋冠状动脉直径在跑步机运动前后α 1-肾上腺素能阻滞哌唑嗪在8个instrumented狗。在输注哌唑嗪之前，运动导致冠状动脉血管阻力下降（2.1 +/- 0.4至1.6 +/- 0.2单位，p <0.05）和冠状动脉回旋支扩张（4.66 +/- 0.37至4.79 +/- 0.34 mm，p <0.05）。运动时冠状动脉内输注哌唑嗪导致冠状动脉血管阻力进一步降低（1.6 +/- 0.2至1.4 +/- 0.2单位，p <0.05），回旋冠状动脉直径进一步增加（4.79 +/- 0.34至4.83 +/- 0.34 mm，p <0.05）。运动时冠状动脉内输注不含哌唑嗪的溶媒未导致冠状动脉血管阻力进一步降低或冠状动脉直径增加。哌唑嗪未引起心率、主动脉压或冠状动脉血流量显著增加。因此，小冠状动脉阻力血管和大心外膜冠状动脉在运动过程中扩张，并进一步扩大后α-肾上腺素能block. CONCLUSION这一发现表明，α 1-肾上腺素能活动在运动限制扩张的大小冠状动脉。
BACKGROUNDExercise-induced dilation of coronary resistance vessels is limited by alpha-adrenergic mechanisms. However, the effect of alpha-adrenergic mechanisms on large coronary arteries during exercise is not known.METHODS AND RESULTSIn the present study, sonomicrometry was used to measure circumflex coronary arterial diameter during treadmill exercise before and after alpha 1-adrenergic blockade with prazosin in eight instrumented dogs. Before infusion of prazosin, exercise caused a fall in coronary vascular resistance (2.1 +/- 0.4 to 1.6 +/- 0.2 units, p less than 0.05) and dilation of the circumflex coronary artery (4.66 +/- 0.37 to 4.79 +/- 0.34 mm, p less than 0.05). Intracoronary infusion of prazosin during exercise caused a further decrease in coronary vascular resistance (1.6 +/- 0.2 to 1.4 +/- 0.2 units, p less than 0.05) and a further increase in circumflex coronary arterial diameter (4.79 +/- 0.34 to 4.83 +/- 0.34 mm, p less than 0.05). Intracoronary infusion of vehicle without prazosin during exercise did not cause a further decrease in coronary vascular resistance or increase in coronary diameter. Prazosin caused no significant increase in heart rate, aortic pressure, or coronary blood flow. Therefore, both small coronary resistance vessels and large epicardial coronary arteries dilated during exercise and dilated further after alpha-adrenergic blockade.CONCLUSIONSThis finding indicates that alpha 1-adrenergic activity during exercise limits dilation of both large and small coronary arteries.