ABSTRACT
Sodium channels Calcium channels Potassium channels Membrane action potential Electrical coupling (GAP junction) Mechanism of cardiac arrhythmias
SODIUM CHANNELS The sodium (Na) channel is a voltage-gated channel that is responsible for the rapid depolarization of conducting myocardial cells. This is important for mechanical synchrony. It has been mapped to chromosome 3 (SCN5A). It consists of one alpha and occasionally one or multiple beta subunits. The beta subunits are auxiliary units and their role in cardiac myocytes is not well understood. The alpha subunit consists of four charged domains arranged in a clockwise manner to form a single-pore, highly selective, monovalent channel.1
