莲心碱对心肌电活动及机械活动的影响

Effets of liensinine on electrical and mechanical activities in isolated guinea pig myocardium

莲心碱（Ｌｉｅ）１－３００ｕｍｏｌ·Ｌ１可浓度依赖性地降低离体豚鼠乳头状肌收缩力（Ｆｅ）和快反应劝作电位（ＡＰ）的零相上升幅度（ＡＰＡ）及最大除极速率（Ｖｍａｘ），延长动作电位时程（ＡＰＤ），且对Ｖｍａｘ的抑制作用有频率依赖性；同浓度下，其作用强于奎尼丁。对高Ｋ＋诱发的慢ＡＰ，Ｌｉｅ也能剂量依赖性地降低ＡＰＡ，Ｖｍａｘ，Ｆｅ，其作用弱于维拉帕米。Ｌｉｅ还可对抗乙酰胆碱缩短ＡＰＤ的作用提示Ｌｉｅ对Ｎａ＋，Ｋ＋Ｃａ２＋的跨膜转运均有非特异性阻滞作用。

The effects of liensinine (Lie )on ae -tion potenthl(AP)and eontraetile foree(Fe)in iso-lated guinea pig myocardium were simultaneously ex- amined Lie1-300 umol·L could concentrationdependently reduce Fe,decline the amplittide(APA),Vmam.and prolong the duration(APD)of the action po-tential And it reduced Vmax、in a frequency depen-dent manner Lie could still concentrationdependently reduce the APA Vmax of the slow AP、and Fe At the same concentration the effeets of Lieon all the ahove parameters of the fast AP were strong-er than those of quinidine but effeets of Lie on those of the slow AP were mueh weaker than those of verapamil The effeet of acetylcholine 30 umol L on shortening the APD of the left auriele eould be antagonized by Lie 30umolL The antiarrhythmie effects of Lie can be explained by a nonspecific inhibi-tion of the current of Na+i K+ and ca2+