PNS单体Rb_l对豚鼠心脏乳头肌动作电位和收缩力的影响

目的 :了解PNS单体Rbl对豚鼠心脏乳头肌动作电位和收缩力的影响。方法 :运用带有动作电位和收缩力分析软件控制的细胞内微电极技术 ,研究了三七皂苷 (PNS)单体Rbl对豚鼠正常心脏乳头肌动作电位 (AP)各特征参数及收缩力 (FC)的影响。结果 :Rb1 1 0～ 30 μmol·L- 1 分别使APD 2 0 ,APD 90明显缩短 ,FC显著下降 (P<0 .0 1 ,n =5) ,并可降低高钾诱发的豚鼠乳头肌慢反应动作电位的动作电位幅值 (APA)及零相最大上升速率(Vmax) (P <0 .0 5 ,n =5)。但对静息电位 (RP) ,APA ,Vmax及AP的超射值 (OS)无明显影响 (P >0 .0 5 ,n =5)。另外 ,Rbl可浓度依赖性地抑制乳头肌收缩力 (FC) ,RP ,APA不随Rbl剂量增加而产生明显变化 ,呈典型的兴奋 收缩脱藕联。结论 :其效应可能通过阻滞钙通道而产生

Effects of Rb_l on Action Potentials and Force of Contractionin Guinea Pig Ventricular Papillary Muscles

Objective: To evaluate the effects of Rbl on action potentials and force of contraction in guinea pig ventricular papillary muscles. Method: The ventricular papillary muscles of guinea pig were isolated regularly and immersed with Tyrode, s solution . The effects of Rbl ( purified saponins of panaxnotoginseng) on the action potentials (AP) , the slow action potentials and the force of contraction (FC) of the muscles were studied . The AP and FC were measured synchronously. Result: Rb l shortened the duration of AP, including APD2O and APD90, and reduced the FC( n=5, P <0.01), but didn't affect the rest potential (RP), the amplitude of action potential(APA), overshot (OS) and maximal upstrok velocity (Vmax). Rbl also decreased the APA of slow action potential, but quinidine had no such effects. Conclusion: Rb l may be a channel blocker.