Yoshino M, Someya T, Nishio A, Yabu H
Department of Physiology, Sapporo Medical College, Japan.
Pflugers Arch. 1988 Feb;411(2):229-31. doi: 10.1007/BF00582322.
Whole-cell and single Ca channel currents were recorded in smooth muscle cells isolated from guinea-pig taenia coli to examine whether multiple types of Ca channels exist. Two different types of voltage-dependent Ca channels with different conductances and inactivation kinetics were identified from cell-attached patch clamp recordings using 50 mM Ba in the patch pipettes. One type of channel, with a large conductance of 25 pS, had a threshold of activation near -40 mV and the mean current reconstructed by averaging individual current responses inactivated slowly. A second type of channel, with a small conductance of 12 pS, had a similar threshold value to that of the 25 pS channel, but the averaged current inactivated rapidly. The steady state inactivation of the 12 pS channel was complete at a holding potential of -40 mV. We concluded that both channel types represent fast and slow inactivating voltage-dependent Ca channels which have been found in many excitable cells.
记录从豚鼠结肠带分离的平滑肌细胞中的全细胞电流和单个钙通道电流，以检查是否存在多种类型的钙通道。使用膜片钳微电极中含有50 mM钡的细胞贴附式膜片钳记录，鉴定出两种具有不同电导和失活动力学的电压依赖性钙通道。一种通道，电导为25 pS，激活阈值接近-40 mV，通过平均单个电流响应重建的平均电流缓慢失活。第二种通道，电导为12 pS，与25 pS通道具有相似的阈值，但平均电流快速失活。12 pS通道在-40 mV的钳制电位下稳态失活完成。我们得出结论，这两种通道类型均代表在许多可兴奋细胞中发现的快速和缓慢失活的电压依赖性钙通道。
