Hormonal modulations of calcium channel activity

Hormones and neurotransmitters which modulate the membraneous influx of calcium into the cytoplasm interact with heptahelical receptors coupling to heterotrimeric G-proteins. Whereas early studies on cardiomyocytes demonstrated the involvement of a cAMP (cyclic adenosine monophosphate)-stimulated phosphorylation in the regulation of calcium channels, there is growing evidence for a direct coupling of G-proteins to these channels. Various approaches led to the identification of the subtypes of G-protein involved in these signal transduction processes