运动训练大鼠心肌由兴奋α-肾上腺素受体引起的收缩性变化研究

采用经颈动脉插入心导管测量心肌收缩性指标的实验方法,在心得安阻断心肌β—肾上腺素受体,肾上腺素兴奋α—肾上腺素受体的条件下,观察研究了大鼠经七周游泳训练后心肌由兴奋α—肾上腺素受体引起的收缩性能变化。结果表明,dp/dtmax,d~2p/dt~2max,Vpm和dv/dtmax等反映心肌收缩性能诸指标,均比对照组明显提高(P<0.01),持续时间也明显延长。说明经游泳训练后,大鼠心肌由α—受体兴奋引起的收缩性增强。这一结果提示:运动训练提高了心肌β—和α—肾上腺素受体的协同调节作用,使心脏在运动中对交感兴奋作出的反应更为完善有效。

Effect of Exercise on Rat''''s Myocardiai Contractility Elicited by Excited a-adrenoceptors

The method of left ventricular catheterization via the carotid to measure the indexes of myocardial contractility was used to observe and study the changes of the rat's myocardial contractility elicited by excited a-adrenoceptors after the rats had been trained in swimming for seven weeks . The study was carried out with the ?adrenoceptor blockaded and the a-adrenoceptors excited . The results showed that the indexes of the trained rats which indicate myocardial contractility , such as dp/dt max , d2p/dt2 max , Vpm and dv/dt max were noticeably higher (P<0. 01) and lasted longer than those of the rats in the control group . After training in swimming , the rat's myocardial contractility elicited by excited a-adrenoceptors was strengthened. These results suggest that sports training can improve the coordination of myocardial ?and a-adrenoceptors and make the heart become more perfect and efficient in its reaction to sympathetic nerve excitation.