Regulation of cardiac L-type calcium current by phosphorylation and G proteins

Voltage-dependent Ca super(2+) channels play a major role in the electromechanical coupling of cardiac cells. During the plateau phase Ca super(2+) entry induces a Ca super(2+)-dependent Ca super(2+) release from the sarcoplasmic reticulum and consequently the initiation of contraction. Voltage-dependent Ca super(2+) channels are also involved in the spontaneous impulse generation as well as in the duration of the action potentials and hence in refractoriness. Ca super(2+) channels are also the target of various hormones and neurotransmitters. The progress has been made possible by the availability of purified biochemical compounds and new biophysical techniques, i.e. isolated cells and the patch-clamp technique.