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兔心室肌细胞电生理异质性研究--缺血对动作电位和钾流的影响
作者姓名:Qi XY  Shi WB  Wang HH  Zhang ZX  Xu YQ
作者单位:1. 上海中医药大学生理教研室,上海,200032
2. 上海第二医科大学生理教研室,上海,200025
摘    要:实验用全细胞膜片箝技术,观察正常及缺血条件下,兔心内膜下心室肌细胞与心外膜下心室肌细胞的动作电位和稳态外向钾流及其变化。结果显示:(1)正常条件下,心外膜下心室肌细胞与心内膜下心室肌细胞动作电位形态有差异,心外膜下心室肌细胞动作电位时程(APD)较短,复极1期后有明显的初迹,动作电位形态是“锋和圆顶”,而心内膜下心室肌细胞APD较长,并且没有上述动作电位形态特征。这两类细胞静息电位无差异。(2)在

关 键 词:心室肌细胞  电生理异质性  动作电位  缺血  钾流

A study on the electrophysiological heterogeneity of rabbit ventricular myocytes the effect of ischemia on action potentials and potassium currents
Qi XY,Shi WB,Wang HH,Zhang ZX,Xu YQ.A study on the electrophysiological heterogeneity of rabbit ventricular myocytes the effect of ischemia on action potentials and potassium currents[J].Acta Physiologica Sinica,2000,52(5):360-364.
Authors:Qi X Y  Shi W B  Wang H H  Zhang Z X  Xu Y Q
Institution:Department of Physiology, Shanghai University of Traditional Chinese Medicine, Shanghai 200032.
Abstract:With the whole-cell variant patch-clamp technique, action potentials (AP) and outward potassium currents of rabbit ventricular myocytes isolated from subendocardium and subepicardium were recorded and their changes were observed under normal and ischemia conditions. The results showed that (1) under normal condition, there were differences in the AP figures between ventricular subendocardial and subepicardial myocytes. Action potentials recorded from subepicardial myocytes had shorter action potential duration (APD) and a notch between phases 1 and 2, compared with those of subendocardial myocytes. The resting potential had no significant difference between these two populations of the action myocytes; (2) under ischemia condition, the notch of action potentials of subepicardial myocytes disappeared and the APD was shortened even more, compared with that of subendocardial myocytes; (3) under normal condition, the density of steady-state outward potassium currents of subepicardial myocytes was significantly greater than that of subendocardial myocytes; (4) under ischemia condition, the increase of steady-state outward potassium currents of subepicardial myocytes was greater than that of subendocardial myocytes. Glybenclamide could partly reverse the above changes. It is suggested that the increase of steady-state outward potassium currents during ischemia is mainly due to the opening of I(K-ATP) channels as a result of the deficiency of intracellular ATP caused by ischemia.
Keywords:ventricular myocytes  electrophysiological heterogeneity  action potential  ischemia  outward potassium current
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