Cav1.3 and Cav1.2 channels of adrenal chromaffin cells: Emerging views on cAMP/cGMP-mediated phosphorylation and role in pacemaking

► Cav1.2 and Cav1.3 L-type channels are highly expressed in mammalian adrenal chromaffin cells. ► Both isoforms are equally up-modulated by cAMP/PKA and down-modulated by NO/cGMP/PKG. ► When opposingly stimulated, PKA and PKG cause up to a factor of ten Ca2 + current variations. ► Cav1.3 allows sufficient inward Ca2 + current to surge at sub-threshold potentials. ► The Cav1.3 current sets the firing frequency by triggering BK and SK currents.