Paradoxical facilitation of exocytosis by inhibition of L-type calcium channels of bovine chromaffin cells

► Ca2+ entry through the L-subtype of VDCCs selectively regulate the endocytotic response after the application of a depolarizing pulse. ► L channel blockade with nifedipine transformed the exocytotic responses elicited by a double-pulse protocol, from depression to facilitation. ► This effect was mimicked by dynasore, calmidazolium, GTP-γS and GDP-βS. ► Ca2+ entry through PQ regulates fast exocytosis while Ca2+ entry through L channels preferentially controls rapid endocytosis.