L-TYPE Ca2+ CHANNEL FUNCTION AND MODULATION

The L-type Ca2+ channel on the surface membrane of cardiac cells opens under the membrane depolarization during the action potential and gates the Ca2+ entry into the cell.  This Ca2+ entry, in turn, triggers the Ca2+ release from intracellular stores, setting forth the excitation-contraction coupling in cardiac muscle cells.  We study the regulation of L-type Ca2+ channels by various modulators including beta1- and beta2-adrenergic stimulation and Ca2+-calmodulin-CaMKII signaling, using the whole-cell voltage clamp and single channel recording techniques as shown in the figure below.