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本实验在35只兔心脏上观察了α和β受体阻断剂对心肌缺血早期MET变化的影响,并初步分析了α受体阻断剂抗心律失常效应的作用机理。实验结果表明,β与α受体阻断剂对MET 的影响明显不同。β受体阻断剂心得安可使正常心脏与缺血心脏的MET同等程度的升高,而对阻断冠脉后 MET的降低无改善作用。与此相反,α受体阻断剂哌唑嗪对正常心脏的MET 无明显影响,但可使阻断冠脉血流后 MET降低的百分率明显减轻,此效应与血压变化和扩血管作用无直接关系。上述结果提示,β受体阻断剂可通过提高正常和缺血心脏MET 的绝对值发挥抗心律失常效应,而α受体阻断剂则有特异性的提高缺血心肌MET 的作用。
In this experiment, we observed the effect of α and β blockers on the changes of early myocardial MET in 35 rabbits, and analyzed the mechanism of antiarrhythmic effect of α blockers. The experimental results show that, β and α blockers on the impact of MET significantly different. Beta-blocker propranolol can make normal heart and ischemic heart MET increased to the same extent, but did not improve the reduction of MET after blocking the coronary artery. In contrast, prazosin, an alpha-blocker, had no significant effect on MET in normal hearts, but significantly reduced the percentage of MET reduction after coronary blood flow was blocked, which was not directly related to changes in blood pressure and vasodilation relationship. The above results suggest that beta blockers can exert anti-arrhythmic effects by increasing the absolute values of MET in normal and ischemic hearts, whereas alpha blockers specifically increase MET in ischemic myocardium.