钙激活氯通道电生理特性及调节机制

Electrophysiological Characterization and Regulation Mechanism of Calcium-activated Chloride Channels

钙激活氯通道(Calcium-activated Chloride Channels,CaCC)在许多生理过程中起着重要作用,如分泌蛋白及盐的跨上皮转运、神经元兴奋、平滑肌生理特性的维持、卵母细胞受精和心脏动作电位的复极化等。CaCC电生理特性较复杂,其全细胞电流随胞内钙离子浓度和刺激电压的不同而表现出不同整流特性和时间电压依赖性,不同组织的单通道电导有很大差异,大小介于1～70pS。CaCC可被NFA、9-AC、DPC、DIDS所阻断。目前CaCC通道蛋白的分子结构还不清楚,已克隆的两种蛋白家族CLCA和Bestrophin可作为其候选分子。本文综述了CaCC的电生理特性、调节机制、分子结构和生理功能。

Calcium-activated Chloride Channels （CaCC） play important roles in a variety of physiological processes such as secretion of proteins, salt vans-epithelial transport, and excitability of neurons, maintenance of smooth muscle physiological tone, oocyte fertilization and repolarization of the cardiac action potentials. The electrophysiological characterization of CaCC is complex. The whole-cell currents exhibit different characterizations of rectification and time, voltage dependence response upon different [Ca^2＋]i and membrane potentials, and single-channel conductance of CaCC is different （1-70pS） in different kinds of organizations. CaCC is blocked by many agents such as NFA, 9-AC, DPC, DIDS. Now, the molecule structures of CaCC have still not been continued. CLCA and Bestrophin gene family cloned recently may be its molecular candidates. The paper overviewed the electrophysiological characterization, mechanism of regulation, molecular structures and physiological fimctions of CaCC.