Characteristics of the inward-rectifying potassium current in mouse ventricular myocytes and its relation to early after-depolarization  

作　　者：周盈颖 郝雪梅 范劲松 刘泰(木逢) 

机构地区：[1]State Key Laboratory of Biomembrane and Membrane Engineering, College of Life Sciences, Peking University, Beijing 100871, China

出　　处：《Science China(Life Sciences)》1996年第2期133-143,共11页中国科学（生命科学英文版）

摘　　要：The properties of the inward-rectifying potassium current (IK1) were studied in the single myocytes isolated from adult mouse ventricles by the whole-cell patch-damp technique for the first time. Most of the properties of IK1 including channel conductances, activation, inactivation, rectification and external K+ sensitivity in mouse ventricular myocyte were similar to those in other species, but the current-voltage (1-V) curve of mouse ventricular myocyte showed no negative slope, i.e the slope in the range of membrane potential 50 mV positive to the reversal potential (VRev) was virtually flat and remained at a low current level ((59±39) pA). Under the superfusion of Tyrode's solution with 3mmol/L K+ and 3mmol/L Cs+, IK1 in the above region nearly decreased to zero, and then the early after-depolarization (EAD) occurred. The results suggest that this distinctive characteristic of IK1 in mouse ventricular myocyte may relate to the high susceptibility to EA0 in mouse myocardium. The inhibition of IK1 seems to be a prerequisite for the occurrence of EAD in this experiment.The properties of the inward-rectifying potassium current (IK1) were studied in the single myocytes isolated from adult mouse ventricles by the whole-cell patch-damp technique for the first time. Most of the properties of IK1 including channel conductances, activation, inactivation, rectification and external K+ sensitivity in mouse ventricular myocyte were similar to those in other species, but the current-voltage (1-V) curve of mouse ventricular myocyte showed no negative slope, i.e the slope in the range of membrane potential 50 mV positive to the reversal potential (VRev) was virtually flat and remained at a low current level ((59±39) pA). Under the superfusion of Tyrode’s solution with 3mmol/L K+ and 3mmol/L Cs+, IK1 in the above region nearly decreased to zero, and then the early after-depolarization (EAD) occurred. The results suggest that this distinctive characteristic of IK1 in mouse ventricular myocyte may relate to the high susceptibility to EA0 in mouse myocardium. The inhibition of IK1

关 键 词：inward-rectifying POTASSIUM current EARLY after-depolarization ventricular MYOCYTE cesium potassium. 

分 类 号：Q41[生物学—生理学]