摘要
用膜片钳全细胞方法研究犬心室肌内膜、中层 (M细胞 )及外膜细胞的L型钙电流的特性 ,并观察nifedipine(1μM)对三层心肌单个细胞动作电位的影响。结果 :心室肌内膜、M及外膜细胞在去极电压为 +10mv时 ,ICa ,L的峰电流pA/pF分别为 - 4.2 9± 1.2 4、- 5 .30± 0 .38、- 4.0 3± 1.19,P <0 .0 5。Nifedipine(1μM)对三层细胞动作电位均缩短。心室肌内膜、M及心外膜细胞动作电位复极化达 90 %时程分别由用药前的 44 7.3± 47.0 ,5 2 4.2± 5 5 .2 ,438.2±39.3ms缩短至用药后的 30 2 .4± 42 .7,30 5 .4± 37.2 ,30 3.3± 37.6ms ,缩短率 32 .8% ,41.5 % ,33 .6 % (P <0 .0 5 )。表明犬心室肌内膜、M及外膜细胞的L型钙电流分布的差异性 。
The characteristics of L-type calcium current and the effects of nifedipine on action potential duration(APD) were investigated in isolated single cells from canine left ventricular epicardial,midmyocardial (M) and endocardial cells by using the patch-clamp whole cell techniques.The results showed that the current(pA/pF) of L-type calcium was-4.29±1.24,-5.30±0.38,-4.03±1.19( P <0.05) in endocardial,M and epicardial cells,respectively.Nifedipine(1 μM) reduced APD from 447.3±47.0,524.2±55.2 ,438.2±39.3 ms to 302.4±42.7(32.8%),305.4±37.2(41.5%),303.3±37.6 ms(33.6%)( P <0.05)respectively in endocardial,M and epicardial cells.The different distribution of L type calcinm current in canine left ventricular epicardial,midmyocardial (M) and endocardial cells,May be the ionic reason of M cell developing afterdepolarizations and triggered activity.
出处
《中国心脏起搏与心电生理杂志》
2001年第1期22-24,共3页
Chinese Journal of Cardiac Pacing and Electrophysiology
基金
国家自然科学基金资助项目 (批号 3980 0 0 71)
