牛蛙球囊毛细胞A型钾离子流的研究

A-Type Potassium Currents in Bull-frog Saccular Hair Cells

为了进一步探讨前庭毛细胞膜上钾通道的类型及动力学特征，本实验用全细胞式膜片钳技术在牛蛙球囊毛细胞侧膜上研究了钾通道电流。结果表明：（１）阻断内向电流后，当钳制电位为－１００ｍＶ，阶跃从－７０ｍＶ至＋２０ｍＶ，随着膜电位的去极化，可记录到快速、瞬时的Ａ型钾通道电流，４－Ａｐ对其有特异性阻断作用。激活电压为（－５３．８３±７．８）ｍＶ。（２）Ａ型钾通道的数量在牛蛙毛细胞间存在差异。（３）除Ａ型钾通道外，细胞膜上还含有其它类型的钾通道，这种钾通道能被ＴＥＡ阻断，其性质待定。

In order to further explore the type and the kinetic feature of potassium channel on the vestibular hair cells membrane, whole-cell patch-cl amp technique was used to investigate potassium current on the bull-frog's saccular hair cells in this experiment. The experimental result showed: 1. When holding potential was -100 mV, rapid and instant current of A-type potasium channel could be recorded by the depolarizing voltage pulse from -70 mV to +20 mV and could be blocked, specially by 4-Ap after inward current was blocked. The activated membrane potential was (-53.83±7.8) mv.2. The amount of the A-type potassium channels were different among various hair cells. 3. Besides A-type potassium channels, there were others potassium channels on the hair cells membrane. They could be blocked by TEA. The nature remained to be further investigated.