G-protein inhibition of N- and P/Q-type calcium channels

Neuronal HVA calcium channels are important regulators of the neuronal activity. By controlling the flow of the extracellular calcium into cytoplasm, these proteins trigger neurotransmitter release, alter action potential firing, and induce gene expression. Correspondingly, the G-protein-mediated modulation of the HVA channels is of extreme importance. It was recently demonstrated that the activity of P/Q and N-types calcium channels is differentially modulated by G-proteins that results in different extents of their inhibition. The fine tuning of Ca2+ channel activity by intracellular proteins is thus of the extreme physiological importance in the regulation of Ca2+ influx into neurones by neurotransmitters and hormones.