Coupling of L-type voltage-sensitive calcium channels to P2X(2) purinoceptors in PC-12 cells
SCIE
SCOPUS
- Title
- Coupling of L-type voltage-sensitive calcium channels to P2X(2) purinoceptors in PC-12 cells
- Authors
- Hur, EM; Park, TJ; Kim, KT
- Date Issued
- 2001-05
- Publisher
- AMER PHYSIOLOGICAL SOC
- Abstract
- 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 [H-3] 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 P2X(2) and P2X(4) receptor mRNAs were detected, studies with pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid revealed that P2X(2) 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 P2X(2)-mediated activation of VSCCs. We report that depolarization induced by Na+ entry through the P2X(2) purinoceptors effectively activates L-type VSCCs in PC-12 cells.
- Keywords
- ATP; nifedipine; depolarization; RAT PHEOCHROMOCYTOMA CELLS; PC12 CELLS; ATP RECEPTOR; SIGNALING PATHWAYS; CA2+ CHANNELS; NA+ INFLUX; NEURONS; ELEMENTARY; ACTIVATION; INHIBITION
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/19580
- DOI
- 10.1152/ajpcell.2001.280.5.C1121
- ISSN
- 0363-6143
- Article Type
- Article
- Citation
- AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY, vol. 280, no. 5, page. C1121 - C1129, 2001-05
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