Extracellular ATP elevates cytosolic Ca²⁺ by activating P2X and P2Y purinoceptors and voltage-sensitive Ca²⁺ channels (VCCCs) in PC-12 cells, thereby facilitating catecholamine secretion. We investigated the mechanism by which ATP activates VSCCs. 2-Methylthioadenosine 5'-triphosphate (2-MeS-ATP) and UTP were used as preferential activators of P2X and P2Y, respectively. Nifedipine inhibited the ATP- and 2-MeS-ATP-evoked cytosolic Ca²⁺ concentration increase and [³H]norepinephrine secretion, but not the UTP-evoked responses. Studies with Ca²⁺ channel blockers indicated that L-type VSCCs were activated after the P2X activation. Mn²⁺ entry profiles and studies with thapsigargin revealed that Ca²⁺ entry, rather than Ca²⁺ release, was sensitive to nifedipine. Although P2X₂ and P2X₄ receptor mRNAs were detected, studies with pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid revealed that P2X₂ was mainly coupled to the L-type VSCCs. The inhibitory effect of nifedipine did not occur in the absence of extracellular Na⁺, suggesting that Na⁺ influx, which induces depolarization, was essential for the P2X₂-mediated activation of VSCCs. We report that depolarization induced by Na⁺ entry through the P2X₂ purinoceptors effectively activates L-type VSCCs in PC-12 cells.