绞股蓝总皂甙对单个豚鼠心室肌细胞的钙、钠、钾电流及动作电位的影响

目的研究绞股蓝总皂甙（ＧＰ）对成年豚鼠单个心室肌细胞的动作电位（ＡＰ）、Ｌ－型钙通道电流（ＩＣａ）、快钠通道电流（ＩＮａ）以及内向整流钾通道电流（ＩＫ１）的影响。方法膜片钳全细胞记录。结果５０ｍｇＬ－１ＧＰ能使动作电位时程（ＡＰＤ９０）由给药前的（７０８±２４）ｍｓ缩短到给药后的（３９６±１６）ｍｓ（Ｐ＜０．０１），抑制率５８．１％，动作电位幅值（ＡＰＡ）由给药前的（１２１±７．２）ｍＶ降到给药后的（８６±８．６）ｍＶ（Ｐ＜０．０１），抑制率２４．１％，静息膜电位无明显影响；５～５０ｍｇＬ－１的ＧＰ能浓度依赖性阻滞ＩＣａ和ＩＮａ，但对ＩＫ１无明显影响。结论ＧＰ对缺血心肌的保护作用在于减少“钙超载”和抑制异常兴奋性的产生。

Effect of GP on action potentials,L calcium channel currents,sodium channel currents and potassium channel currents in isolated single ventricular myocyte of guinea pigs

AIM To investigate the effects of GP on action potentials, L calcium channel currents, sodium channel currents and potassium channel currents in isolated single ventricular myocyte of guinea pig. METHODS Whole cell recording by patch clamp technique. RESULTS GP 50 mg·L-1 shortened action potential duration (APD90) 581% and shortened action potential amplitude (APA) 241%, but had no significant effects on rest membrane potential (RMP). GP 5￣50 mg·L-1 inhibitted calcium currents and sodium currents. The inhibition was concentration dependent. GP did not effect inward rectified potassium currents. CONCLUSIONS GP might prevent cardial myocyte from ischemic damage by inhibitting the “calcium overload” and generation of abnormal excitement.