Study On The Permeation And Gating Mechanism Of Calcium Activated Chloride Channels

The magic of life lies in that it can exchange energy, information and materialwith environment in a continuous way. Ion channels play an essential role ininformation and material exchanges in organisms. Calcium activated chloride channel(CACC), as an important member of ion channels, is a kind of widely distributedchannel in various tissues, which has various functions as follows regulation ofneuronal excitability, smooth muscle contraction maintainance, oocyte fertilizationand cardiac action potential repolarization and so on.In this study, the author took TMEM16A/CACC stablely-transfected HEK293cell line as study object and focused on the electrophysiological properties of theCACCs channel with an inside-out patch clamp recording modes. Based on the study,we drew the preliminary conclusions as follows:First, we studied on the calcium ion concerntration dependance of TMEM16Achannels which is stablely transfected in HEK293 cell lines. Our results showed thatboth the current-voltage (I-V) curves and rectification of TMEM16A channel havecalcium dependence.Second, we compared the difference of the electrophysiological properties ofTMEM16A when it was activated by various intracellular or extracellularconcentrations of calcium ion, and confirmed that calcium ion binding sites ofTMEM16A should locate in the intracellular side. Third, we studied the inhibitory effect of TMEM16A induced by NFA. We alsofound that a long time inside-out recording would induce the irreversible rundown ofTMEM16A current .