锌对心肌保护作用机理的探讨

应用电镜、电子示踪技术和立体计量测试法，从形态学上观察异丙基肾上腺素对心肌膜系统的影响及锌的保护作用，同时应用标准玻璃微电极技术和微机实时分析方法，研究异丙基肾上腺素致心肌损伤及锌对心肌保护作用的机理。实验结果表明：异丙基肾上腺素可引起心肌细胞膜系统损伤，此时心肌细胞的去极化和复极化过程均发生改变；经锌前处理后，心肌损伤程度明显减轻，心肌细胞的复极化过程得到明显改善。锌对心肌的保护作用，主要是通过阻断心肌细胞膜慢通道、减少平台期钙离子内流、防止细胞内钙超载来实现。

Studise on the mechanism of the protective effect of Zinc on the myocardial cells

Effect of isoproterenol (ISO) on the myocardial cellular electrical activity, pathologic changes and protective effect of Zn were observed by means of conventional microelectrode and pathological technique on the isolated ventricular papillary muscle cells of the guinea pigs. ISO can affect depolarization and repolarization of the myocardial cells during myocardial injury. It made APA,OS, RP and Vmax decreased,APD prolonged after injecting ISO 24h,and APD shortened after 48h. The effct of ISO on the repolarization of the cardial cells was exerted by the changes of plateau chiefly. Zn can weakan the electrical response and injurious degree of ISO on the myocardial cells,make APD improved obviously,the changes of the APD corresponded with the changes of the plateau of the action potential.The experiment results showed:The protective effct of Zn on the cardiac muscles was achieved by blocking the slow channel in the myocardial cellular membrane,influencing calcium ions inward current,decreasing the intracellular calcium load, and then opposing calcium overload - induced myocardial injury.