Referenced in: none

Automatically associated channels: Kv4.1

Title: Characterization of Cardiac Anoctamin1 Ca²⁺-Activated Chloride Channels and Functional Role in Ischemia-Induced Arrhythmias.

Authors: Zhen Ye, Ming-ming Wu, Chun-Yu Wang, Yan-Chao Li, Chang-Jiang Yu, Yuan-Feng Gong, Jun Zhang, Qiu-shi Wang, Bin-Lin Song, Kuai Yu, H Criss Hartzell, Dayue Darrel Duan, Dan Zhao, Zhi-Ren Zhang

Journal, date & volume: J. Cell. Physiol., 2015 Feb , 230, 337-46

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/24962810

Abstract
Anoctamin1 (ANO1) encodes a Ca(2+)-activated chloride (Cl(-)) channel (CaCC) in variety tissues of many species. Whether ANO1 expresses and functions as a CaCC in cardiomyocytes remain unknown. The objective of this study is to characterize the molecular and functional expression of ANO1 in cardiac myocytes and the role of ANO1-encoded CaCCs in ischemia-induced arrhythmias in the heart. Quantitative real-time RT-PCR, immunofluorescence staining assays, and immunohistochemistry identified the molecular expression, location, and distribution of ANO1 in mouse ventricular myocytes (mVMs). Patch-clamp recordings combined with pharmacological analyses found that ANO1 was responsible for a Ca(2+)-activated Cl(-) current (I(Cl.Ca)) in cardiomyocytes. Myocardial ischemia led to a significant increase in the current density of I(Cl.Ca), which was inhibited by a specific ANO1 inhibitor, T16A(inh)-A01, and an antibody targeting at the pore area of ANO1. Moreover, cardiomyocytes isolated from mice with ischemia-induced arrhythmias had an accelerated early phase 1 repolarization of action potentials (APs) and a deeper "spike and dome" compared to control cardiomyocytes from non-ischemia mice. Application of the antibody targeting at ANO1 pore prevented the ischemia-induced early phase 1 repolarization acceleration and caused a much shallower "spike and dome". We conclude that ANO1 encodes CaCC and plays a significant role in the phase 1 repolarization of APs in mVMs. The ischemia-induced increase in ANO1 expression may be responsible for the increased density of I(Cl.Ca) in the ischemic heart and may contribute, at least in part, to ischemia-induced arrhythmias.