Ca channels in cardiac myocytes: structure and function in Ca influx and intracellular Ca release.
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.
Bers
D M
DM
Department of Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA. dbers@luc.edu
Perez-Reyes
E
E
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D015640:Ion Channel Gating / Q000502:physiology*; D017136:Ion Transport; D009206:Myocardium / Q000378:metabolism*; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012508:Sarcolemma / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism; D013329:Structure-Activity Relationship
D015220:Calcium Channels; D019837:Ryanodine Receptor Calcium Release Channel; D015222:Sodium Channels; D002118:Calcium