ATP和凝血酶诱导的血管内皮细胞Ca~(2+)内流比较

采用fura 2荧光测定细胞 Ca2 +]i 变化技术 ,在培养的牛主动脉内皮细胞上观察ATP和凝血酶诱导的Ca2 +内流的特性 .ATP和凝血酶均能诱导内皮细胞 Ca2 +]i 呈双相升高 ,它们诱导的Ca2 +释放是环匹阿尼酸 (CPA)敏感Ca2 +池的一部分 .ATP诱导的Ca2 +释放和Ca2 +内流不完全通过激活磷脂酶C介导 ,而凝血酶诱导的Ca2 +释放和Ca2 +内流则完全通过激活磷脂酶C介导 .硝苯地平对ATP和凝血酶诱导的Ca2 +内流均无影响 ;SK&F 96 36 5与三七皂甙 2A对凝血酶诱导的Ca2 +内流没有影响 ,但可抑制ATP诱导的Ca2 +内流 ,且此作用比它们对CPA诱导Ca2 +内流的抑制作用小 .SK&F 96 36 5和三七皂甙 2A敏感的Ca2 +内流的特性不同 .结果表明ATP和凝血酶激活不同受体 ,引起Ca2 +内流的机理不同

Comparison of ATP and thrombin-induced Ca2+ entry in vascular endothelial cells

The effects of drugs on intracellular calcium concentration(［Ca2+］i) were investigated with fura-2 fluorescence technique to investigate ATP and thrombin-induced Ca2+ entry in bovine aortic endothelial cells(BAEC). It was found that application of ATP and thrombin gave rise to biphasic ［Ca2+］i elevation. ATP or thrombin only triggered a fraction of cyclopiazonic acid(CPA)-sensitive Ca2+ store, which was enough to activate Ca2+ entry. The Ca2+ release induced by thrombin resulted from the activation of phospholipase C(PLC), whereas the PLC-independent mechanism was involved in ATP-induced Ca2+ release. Nifedipine had no effect on ATP and thrombin- induced Ca2+ entry. SK&F 96365 and ginsenoside-2A inhibited both ATP and CPA-induced Ca2+ entry, however no effect of them on thrombin-induced Ca2+ entry was found. The inhibitory effects of SK&F 96365 and ginsenoside-2A on CPA-induced Ca2+ entry were less than that on ATP-induced Ca2+ entry. The Ca2+ influx sensitive to SK&F 96365 was not the same as that to ginsenoside-2A. These observations suggest that both ATP and thrombin evoke Ca2+ release and Ca2+ influx by activation of different receptor. However their mechanisms appear different.