钙激活性钾通道是人小肠上皮细胞的容积调节性通道(英文)

目的 :研究细胞容积调节机制 ,探讨人类小肠上皮细胞调节性容积减小 （RVD）过程中离子通道的作用及其种类。方法 :膜片钳全细胞记录和单通道记录法记录培养的人类小肠上皮细胞 RVD过程中电流的变化 ,细胞容积测定法观察 RVD过程中特异性钙激活性钾通道阻断剂 （clotrimazole）的作用。结果 :全细胞记录法证实细胞 RVD过程中 K+通道和 Cl-通道电流同时被激活 ,该 K+通道电流具有明显的钙依赖性并可被 clotrim azole阻断。单通道记录法进一步证实 RVD过程中激活的 K+通道为 Interm ediate- conductance钙激活性钾通道。结论 :人类小肠上皮细胞在低渗溶液作用下具有 RVD过程 ,钙激活性钾通道在 RVD过程中具有十分重要的作用。

Ca2+-activated K+ channel is a volume regulatory channel in epithelial cells

The regulatory volume decrease (RVD) is an essential function of the cell. In most cell types, RVD is accomplished mainly by KCl efflux induced by parallel activation of K + and Cl- channels. This investigation was aimed to study the K + channel that was responsible for the RVD in human intestine 407 cells using patch clamp. Whole-cell recordings showed that hypotonic stress could activate K + current which depended on the intracellular Ca 2+ and was blocked reversibly by an specific intermediate-conductance K + channel(IK) blocker, clotrimazole. This channel was also activated by hypotonic challenge in cell-attached mode. Cell volume measurement confirmed the electrophysiological results. Thus, it is concluded that the IK channel is responsible for K + efflux during the RVD in Intestine 407 cells.