Strader J R, Gwirtz P A, Jones C E
Department of Physiology, Texas College of Osteopathic Medicine, Fort Worth.
J Pharmacol Exp Ther. 1988 Aug;246(2):772-8.
During submaximal exercise, an alpha adrenergic vasoconstriction that opposes metabolic dilation exists in the coronary circulation. Fifteen dogs were given i.c. injections of prazosin (0.5 mg) or yohimbine (0.7 mg) to determine the participation of alpha 1 and alpha 2 adrenoceptors in the vasoconstriction during exercise. All dogs were chronically instrumented to measure left circumflex blood flow, heart rate, regional left ventricular function and global left ventricular function. The experimental protocol consisted of a graded exercise regimen during which, at the highest level of exercise an alpha antagonist was given i.c. Exercise significantly increased heart rate, left ventricular pressure, dP/dt, systolic shortening and rate of shortening, and coronary blood flow. After the prazosin injection there was an increase in circumflex blood flow (25 +/- 3%) as well as regional (38 +/- 6%) and global (20 +/- 3%) contractile function. However, there was no change in circumflex blood flow or myocardial function after yohimbine. These data indicate that during exercise the sympathetic constrictor tone in the coronary circulation is mediated primarily by alpha 1 adrenoceptors, with little or no involvement from alpha 2 adrenoceptors.
在次极量运动期间，冠脉循环中存在一种与代谢性扩张相反的α肾上腺素能血管收缩。给15只狗进行颅内注射哌唑嗪（0.5毫克）或育亨宾（0.7毫克），以确定α1和α2肾上腺素能受体在运动期间血管收缩中的作用。所有狗均长期植入仪器以测量左旋支血流量、心率、局部左心室功能和整体左心室功能。实验方案包括一个分级运动方案，在此期间，在运动的最高水平时进行颅内注射α拮抗剂。运动显著增加心率、左心室压力、dp/dt、收缩期缩短和缩短速率以及冠脉血流量。注射哌唑嗪后，左旋支血流量增加（25±3%），局部（38±6%）和整体（20±3%）收缩功能也增加。然而，注射育亨宾后，左旋支血流量或心肌功能没有变化。这些数据表明，在运动期间，冠脉循环中的交感缩血管张力主要由α1肾上腺素能受体介导，α2肾上腺素能受体几乎没有参与或不参与。
