Molecular basis of the delayed rectifier current I-Ks in heart

Electrical activity underlies the control of the frequency, strength. and d uration of contraction of the heart. During the cardiac cycle, a regular rh ythmic pattern must be established in time-dependent changes in ionic condu ctances in order to ensure events that underlie normal cardiac function, Th is pattern must he tightly regulated by sympathetic nervous activity to ens ure a physiologically relevant relationship between diastolic filling and e lection times with variable heart tate. The duration of the ventricular act ion potential is: controlled in part by a slowly activated potassium channe l current. I-Ks. The molecular identity of the subunits that comprise the c hannels conducting this current is important, not only for understanding th e fundamental mechanisms that control electrical activity in healthy indivi duals, but also for understanding the molecular basis of at least one inher ited human disease. LQTS-1. This brief review summarizes key points of info rmation regarding the molecular determinants of the activity of these chann els, their relationship to human disease, and what is known, and yet to be discovered, about the molecular determinants of the regulation of this chan nel by sympathetic nervous activity. (C) 2001 Academic Press.