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细胞内游离钙浓度在细胞反应的调节中作为第二信使起很重要的作用,本实验采用荧光钙指示剂 quin-2测定血小板胞浆内游离钙浓度[Ca~(2+)]_i 的变化。结果表明在1 mmol/L 外钙的存在下,凝血酶(0.3 U/ml)使血小板[Ca~(2+)]_i 增高4～5倍。但在外钙缺乏的情况下,凝血酶使血小板[Ca~(2+)]_i增加较少。似乎凝血酶增加[Ca~(2+)]_i,部分是通过释放内钙,但主要是通过钙内流。J-894通过减少钙内流和释放明显抑制凝血酶引起的血小板[Ca~(2+)]_i 的升高,剂量与效应相关。提示 J-894可能是一种钙通道阻滞剂。
The intracellular free calcium concentration plays a very important role as a second messenger in the regulation of cellular responses. In this experiment, the change of [Ca 2+] i in the intracytoplasmic free calcium concentration was measured by the fluorescent calcium indicator quin-2 . The results showed that thrombin (0.3 U / ml) increased platelet [Ca ~ (2 +)] _ i by 4-5 fold in the presence of 1 mmol / L extra-calcium. However, in the absence of calcium, thrombin increased platelet [Ca ~ (2 +)] _i less. It appears that thrombin increases [Ca ~ (2 +)] _ i, partly by releasing intracellular calcium, but mainly via calcium influx. J-894 is associated with an increase in platelet [Ca ~ (2 +)] _i induced by reduced calcium influx and release of thrombin. Tip J-894 may be a calcium channel blocker.