低氧对Ⅰ型颈动脉体细胞钾电流的抑制作用：对钙激活钾电流的选择性影响。

Hypoxic suppression of K+ currents in type I carotid body cells: selective effect on the Ca2(+)-activated K+ current.

作者信息

Peers C

机构信息

University Laboratory of Physiology, Oxford, U.K.

出版信息

Neurosci Lett. 1990 Nov 13;119(2):253-6. doi: 10.1016/0304-3940(90)90846-2.

DOI:10.1016/0304-3940(90)90846-2

PMID:1704113

Abstract

Whole-cell K+ currents were recorded in isolated type I carotid body cells using the patch-clamp technique. Hypoxia (pO2 25 torr) reversibly suppressed K+ currents in a voltage-dependent manner: maximal effects were seen at low, positive test potentials, where the Ca2(+)-activated component of K+ currents was greatest. Enhancing this component with 5 microM BAY K 8644 exaggerated the effects of hypoxia, and when the component was inhibited (100 microM Cd2+ or 5 microM nifedipine) hypoxic effects were abolished. As hypoxia does not affect Ca2+ currents directly, these data indicate the suppressive effect of hypoxia is selective for the Ca2(+)-activated component of K+ currents in type I cells.

摘要

采用膜片钳技术在分离的I型颈动脉体细胞中记录全细胞钾电流。低氧（pO2 25托）以电压依赖性方式可逆性抑制钾电流：在低的正测试电位下可观察到最大效应，此时钾电流的钙激活成分最大。用5微摩尔BAY K 8644增强该成分会夸大低氧的效应，而当该成分被抑制时（100微摩尔Cd2+或5微摩尔硝苯地平），低氧效应则被消除。由于低氧不直接影响钙电流，这些数据表明低氧的抑制作用对I型细胞中钾电流的钙激活成分具有选择性。