关键词: 心肌, 细胞学, 动作电位, 钙通道, L型

Abstract: To investigate the effects of panaxadiol saponins monomer Rb₁ on action potential(AP) and L-type calcium channel in ischemic cardiomyocytes of guinea pigs. Methods The Langendorff perfusion method was used to isolatethe ventricular myocytes of guinea pigs and the ventricular myocytes were randomly divided into normal control group,ischemia group and three dose groups of Rb₁ (100,200 and 400 μm•L^-1).The AP of ventricular myocytes was recorded by current-clamp mode and the current of L-type calcium channel was recorded by voltage-clamp mode using whole clamp technique. Results Compared with ischemic cardiomyocytes group,the action potential duration(APD₅₀) and (APD₉₀) were decreased in 100,200 and 400　μm•L^-1Rb₁ groups（P<0.05 or P<0.001）,the peak current of L-type calcium channel in ischemic cardiomyocytes was decreased singnificantly（P<0.05 or P<0.01）after Rb₁ was administered.Panaxadiol saponins monomer Rb₁ inhibited the opening of calcium channel in ischemic cardiomyocytes,the effect of calcium current was reduced with the increasing of Rb₁ dose in a dose -dependent manner. Conclusion Panaxadiol saponins monomer Rb₁ can shorten AP duration of ischemic cardiomyocytes and inhibit the opening of calcium channel which may be one of the critical mechanisms of anti-myocardial ischemia of panaxadiol saponins monomer Rb₁.

Key words: myocardium, cytology, action potentials, calcium channels, L-type