Chen K M, Guan Y Y, Sun J J
Department of Pharmacology, Sun Yat-Sen University of Medical Sciences, Guangzhou, China.
Zhongguo Yao Li Xue Bao. 1993 Nov;14(6):500-4.
The purified direct lytic factors (DLF) from southern Chinese cobra (Naja naja atra) venom induced a contractile response in Ca(2+)-free Krebs' solution and a further increase in the tension following a subsequent addition of Ca2+ into bath. After depletion of intracellular Ca2+ pool by phenylephrine, DLF failed to induce any contractile response. In 45Ca2+ experiments, DLF increased both 45Ca2+ release and 45Ca2+ influx. Procaine 2 mmol.L-1 decreased the DLF induced 45Ca2+ release and 45Ca2+ influx by 67 +/- 23% and 46 +/- 32%, respectively. Nifedipine and verapamil 1 mmol.L-1 markedly inhibited the contractile response and the 45Ca2+ influx induced by DLF. These results suggest that DLF induces extracellular Ca2+ entry through voltage dependent Ca2+ channel and Ca2+ release from the intracellular Ca2+ pool which is sensitive to phenylephrine.
从中国南方眼镜蛇（眼镜蛇）毒液中纯化得到的直接溶解因子（DLF），在无钙的克雷布斯溶液中可诱导收缩反应，随后向浴槽中添加钙离子后，张力会进一步增加。在用去氧肾上腺素耗尽细胞内钙库后，DLF未能诱导任何收缩反应。在45Ca2+实验中，DLF增加了45Ca2+的释放和45Ca2+的内流。2 mmol.L-1的普鲁卡因分别使DLF诱导的45Ca2+释放和45Ca2+内流减少了67±23%和46±32%。1 mmol.L-1的硝苯地平和维拉帕米显著抑制了DLF诱导的收缩反应和45Ca2+内流。这些结果表明，DLF通过电压依赖性钙通道诱导细胞外钙离子进入，并从对去氧肾上腺素敏感的细胞内钙库中释放钙离子。
