Burnashev N A
Gen Physiol Biophys. 1986 Oct;5(5):495-504.
The patch-clamp method was used to examine inward rectifying potassium channels in the membrane of rat ventricular myocytes. Two types of inward rectifying channels strongly selective for K+ ions and with different conductance and kinetics coexist in rat myocardial cells. When the concentration of K+ was 140 mmol/l on the extracellular side of the patch, the conductance was 38.9 pS for type I channels and 25.7 pS for the type II. The type II channels had a detectable conductance (4 pS) at potentials positive than the potassium equilibrium potential. The mean open time was 18 ms at -60 mV patch membrane potential and 12 ms at -100 mV for type I channels, and 1.3 s at -60 mV and 0.94 s at -105 mV for type II channels, respectively. The opening probability of type II channels decreased with hyperpolarization. The type II channels can adopt several (about 10 or more) conductance states, which can occur either within one opening or as individual events.
采用膜片钳方法检测大鼠心室肌细胞膜上的内向整流钾通道。大鼠心肌细胞中存在两种对K⁺离子具有强选择性、电导和动力学不同的内向整流通道。当膜片外侧K⁺浓度为140 mmol/L时，I型通道的电导为38.9 pS，II型通道的电导为25.7 pS。II型通道在高于钾平衡电位的电位下具有可检测的电导（4 pS）。I型通道在膜片电位为-60 mV时平均开放时间为18 ms，在-100 mV时为12 ms；II型通道在-60 mV时为1.3 s，在-105 mV时为0.94 s。II型通道的开放概率随超极化而降低。II型通道可呈现几种（约10种或更多）电导状态，这些状态可在一次开放内出现，也可作为单个事件出现。
