Mechanisms of IhERG/IKr Modulation by α1-Adrenoceptors in HEK293 Cells and Cardiac Myocytes.

Background: The rapid delayed rectifier K+ current (IKr), carried by the hERG protein, is one of the main repolarising currents in the human heart and a reduction of this current increases the risk of ventricular fibrillation. α1-adrenoceptors (α1-AR) activation reduces IKr but, despite the clear relationship between an increase in the sympathetic tone and arrhythmias, the mechanisms underlying the α1-AR regulation of the hERG channel are controversial. Thus, we aimed to investigate the mechanisms by which α1-AR stimulation regulates IKr.

Tamoxifen inhibition of kv7.2/kv7.3 channels.

KCNQ genes encode five Kv7 K(+) channel subunits (Kv7.1-Kv7.5).