摘要
目的研究犬左心室壁外膜层、中层(M细胞)及内膜层细胞的L型钙电流大小,观察氯化镉阻断钙电流后,三层心肌单个细胞跨膜动作电位的变化。方法应用膜片钳全细胞记录技术。结果去极电压为+10mv时,I_(Ca,L)电流的峰值达最大,在心外膜、M细胞及心内膜细胞间存在显著差异,分别为-4.0±1.2、-5.3±0.4及-4.3±1.2pA/pF,(P<0.05)。在其它去极电压,三层细胞钙电流值无显著差异。氯化镉(0.2mM)使三层细胞动作电位均缩短,心内膜、M细胞及心外膜细胞APD_(90)分别由用药前的436.4±39.0ms,511.6±48.7ms,431.8±42.36ms缩短至用药后的293.4±41.7,296.7±50.3,295.2±40.9ms,APD_(90)分别缩短32.8％,42.0％,31.6％(P<0.05)。结论犬心室外膜、中层(M细胞)及内膜细胞的L型钙电流分布的差异性。
objective This study was designed to explore the heterogeneity of L - type calcium current in isolated sin-gle cells from canine left ventricular epicardial, midmyocardial and endocardial cells. Melhods The patch - clamp whole cell techniques was used to record the amplitude of L - type calcium current and the effects of cycle on action potential duration (APD) in isolated single celis from canine left ventricular epicardial, midmyocardial and endocardial cells by using. Results The currents of L - type calcium were significantly different at + 10mV of depolarization voltages. They were - 4.03 ± 1.19,
- 4.29 ± 1. 24, - 5 . 30 ± 0 .38 pA/pF (P < 0.05 ) in epicardial, endocardial and midmyocardial cells respectively. CdCl (0.2mM)reduced APD from 436.4±39.0ms,511 .6±48 .7ms,431 .8±42.36ms to 293 .4± 41 .7,296 .7±50.3,295.2
±40. 9ms, and i. e. the shorting of APD90 were 32 .8 % , 42 .0% , 31 .6 % (P < 0.05) respectively in endocardial, midmyocardial and epicardial cells.
出处
《医学研究通讯》
2000年第11期7-9,共3页
Bulletin of Medical Research
基金
国家自然科学基金
关键词
心室肌细胞
钙通道电流
动作电位
异质性
Ventricular wall myocytes L - type calcium current Action potential duration APD Heterogeneity
