Calcium channel subtypes in porcine adrenal chromaffin cells
Calcium channel subtypes in porcine adrenal chromaffin cells
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猪肾上腺嗜铬细胞的钙通道亚型
DOI：
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发表时间：
1997
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通讯作者：
Y. Nakazato
中科院分区：
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作者：
N. Kitamura;T. Ohta;S. Ito;Y. Nakazato
摘要研究硝苯地平、ω- concontoxin GVIA （ω-CgTx）和ω-agatoxin IVA （ω-AgTx）对钙离子电流、60 mm - k +诱导的细胞内Ca2+浓度（[Ca2+]i）升高和儿茶酚胺分泌的影响，以阐明培养的猪肾上腺染色质细胞中Ca2+通道的亚型。硝苯地平、ω-CgTx和ω-AgTx以剂量依赖性的方式抑制Ca2+电流，表明存在L型、N型和p型Ca2+通道。最大剂量硝苯地平（10 μM）、ω-CgTx （1 μM）和ω-AgTx （0.1 μM）对Ca2+电流的抑制作用分别为对照电流的85%、22%和94%。在同一细胞中观察到这三种阻滞剂的抑制作用，表明猪染色质细胞中至少存在三种Ca2+通道亚型。硝苯地平（10 μM）和ω-CgTx （1 μM）对60 mM K+诱导的[Ca2+]i升高和儿茶酚胺分泌均有抑制作用，ω-AgTx （0.1 μM）无抑制作用。这些结果表明，猪肾上腺染色质细胞中存在L型、N型和p型Ca2+通道，高浓度K+诱导Ca2+进入的主要途径是L型和N型Ca2+通道。
Abstract The effects of nifedipine, ω-conotoxin GVIA (ω-CgTx) and ω-agatoxin IVA (ω-AgTx) on Ca2+ currents, a 60-mM-K+-induced increase in intracellular Ca2+ concentration ([Ca2+]i) and catecholamine secretion were examined to clarify the subtypes of Ca2+ channels in cultured adrenal chromaffin cells from the pig. Nifedipine, ω-CgTx, and ω-AgTx inhibited Ca2+ currents in a dose-dependent manner, suggesting the presence of L-, N- and P-type Ca2+ channels. The maximal doses of nifedipine (10 μM), ω-CgTx (1 μM), and ω-AgTx (0.1 μM) inhibited Ca2+ currents to 85%, 22%, and 94% of control currents, respectively. The inhibitory effects of these three blockers were observed in the same cell, indicating that at least three subtypes of Ca2+ channels are present in porcine chromaffin cells. The increase in [Ca2+]i and catecholamine secretion induced by 60 mM K+ were inhibited equally by nifedipine (10 μM) and ω-CgTx (1 μM), but not by ω-AgTx (0.1 μM). These results suggest that L-, N- and P-type Ca2+ channels are present in porcine adrenal chromaffin cells, and that the major pathways of Ca2+ entry evoked by a high concentration of K+ are L- and N-type Ca2+ channels.