摘要
目的探讨人右心室复极1相瞬间外向钾电流(Ito)的跨壁电不均一性。方法应用全细胞钳制技术,对人右心室心外膜下(Epi)细胞、中间层(M)细胞和心内膜下(Endo)细胞复极1相Ito离子流的电流强度、密度和动力学过程进行研究。结果人右心室三层细胞之间存在明显的Ito离子流电不均一性,在37℃、0·2Hz和除极化试验电压为+70mV时,Epi细胞和M细胞峰值Ito离子流的密度分别为(13·2±2·6)pA/pF,和(8·9±3·1)pA/pF,远大于Endo细胞(2·7±0·35)pA/pF,(P<0·01);在37℃条件下,人右心室Epi细胞和M细胞Ito离子流的激活和失活过程符合Boltzmann分布,两组细胞的激活和失活V1/2、斜率因子K等均差异无统计学意义(P>0·05)。结论在人右心室跨越室壁的3层细胞间,特别是Epi细胞与Endo细胞之间、M细胞与Endo细胞之间,复极1相存在明显的Ito离子流强度差异和强大的Ito离子流梯度。
Objective To investigate the transmural electrophysiological heterogeneity of transient outward potassium current （I10） in repolarization phase 1 of the human right ventricle. Methods Using whole cell patch-clamp technique,we researched the ionic intensity, density and the kinetic process of I10 in repolarization phase 1 from the human right ventricular epicardial cells, mid-myocardial cells （M cells） and endocardial cells. Results Our results showed there was obvious I10 electrophysiological heterogeneity among the three type cells in the human right ventricle. At 37℃, 0.2 Hz and ＋ 70 mV depolarizing test potential, the average peak I10 of epicardial cells and M cells approximately reached （13.2±2.6）pA/pF, 和（8.9±3.1）pA/pF, respectively which were much larger than the I10 of endocardial cells （2.7±0.35）pA/pF （P 〈 0.01）; There were no significant difference in activated and inactivated V1/2, slop factor K etc of I10 （all P 〈 0.01） which belonged to epicardial cells and M cells and their activated and inactivated process were in accordance with Boltzmann distribution. Conclusion These results suggest there exists evident difference and gradient of I10 among the three type myocardial cells, especially between epicardial cells and endocardial cells, M cells and endocardial cells in the human right ventricle.
出处
《中华心律失常学杂志》
2006年第1期28-32,共5页
Chinese Journal of Cardiac Arrhythmias
基金
卫生部科研基金资助项目(98-2-243)
关键词
人
电生理学
心肌
钾通道
Human
Electrophysiology
Myocardium
Potassium channels
