大鼠胰腺β细胞中两种钙通道的单通道记录
Single-channel recordings of two types of calcium channels in rat pancreatic beta-cells.
作者信息
Sala S, Matteson D R
机构信息
University of Maryland School of Medicine, Department of Biophysics, Baltimore 21201.
出版信息
Biophys J. 1990 Aug;58(2):567-71. doi: 10.1016/S0006-3495(90)82400-0.
Using the cell-attached configuration of the patch clamp technique, we have identified two different types of Ca channels in rat pancreatic beta-cell membranes. The two channels differ in single channel conductance, voltage dependence, and inactivation properties. The single-channel conductance, measured with 100 mM Ba2+ in the pipette, was 21.8 pS for the large channel and 6.4 pS for the small channel. The large-conductance channel is similar to the fast deactivating or L-type Ca channel described in other preparations. It is voltage dependent, has a threshold for activation around -30 mV, and can be activated from a holding potential of -40 mV. On the other hand, the small-conductance Ca channel is similar to the SD or T type Ca channel; it has a lower activation threshold, around -50 mV, and it can be inactivated by holding the membrane potential at -40 mV.
运用膜片钳技术的细胞贴附式配置，我们在大鼠胰腺β细胞膜中鉴定出两种不同类型的钙通道。这两种通道在单通道电导、电压依赖性和失活特性方面存在差异。用吸管中100 mM Ba2+测量时，大通道的单通道电导为21.8 pS，小通道为6.4 pS。大电导通道类似于其他制剂中描述的快速失活或L型钙通道。它具有电压依赖性，激活阈值约为 -30 mV，可从 -40 mV的钳制电位激活。另一方面，小电导钙通道类似于SD或T型钙通道；它具有较低的激活阈值，约为 -50 mV，并且通过将膜电位保持在 -40 mV可使其失活。
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