Sarcolemmal and sarcoplasmic reticulum calcium channels are crucial for basic cellular electrophysiological properties, excitation-contraction coupling, and control of cardiac contractility.
This review summarizes the fundamental structure and function of calcium channels in cardiac myocytes, highlighting their critical roles in cellular electrophysiology, excitation-contraction coupling, and arrhythmogenesis.
There are Ca channels in the plasma membrane and also the sarcoplasmic reticulum (SR) membrane in cardiac myocytes. The relationship between channel structure, associated proteins and function of these Ca channels is discussed. The sarcolemmal Ca channels are crucial both to the basic cellular electrophysiological properties and control of cardiac contractility (via excitation-contraction coupling). The intracellular Ca release channels (or ryanodine receptors) respond to triggering events mediated by sarcolemmal ion currents and are largely responsible for releasing Ca which activates the myofilaments to produce contraction. Several possible mechanisms of excitation-contraction coupling are discussed. The Ca released from the SR can also feedback on several sarcolemmal ion currents and alter action potential configuration as well as contribute to arrhythmogenesis.
Donald M. Bers (Sat,) conducted a review in Cardiac myocyte physiology. Sarcolemmal and sarcoplasmic reticulum calcium channels are crucial for basic cellular electrophysiological properties, excitation-contraction coupling, and control of cardiac contractility.