Yatomi Y, Higashihara M, Ozaki Y, Kume S, Kurokawa K
First Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Biochem Biophys Res Commun. 1990 Aug 31;171(1):109-15. doi: 10.1016/0006-291x(90)91363-w.
Cytoplasmic Ca2+ mobilization in human platelets triggered by a CD 9 monoclonal antibody, TP82, was monitored by the Ca2(+)-sensitive photoprotein, aequorin and Ca2(+)-sensitive fluorophores, fura 2 and quin 2. Aequorin-indicated Ca2+ values were proportional to the concentration of TP82, which was in inverse proportion to the lag time before the onset of platelet aggregation and serotonin release. When fura 2 was used as a Ca2+ indicator, above a threshold concentration, the TP82-induced intracellular Ca2+ value remained unchanged even with increasing concentration. The findings obtained with quin 2 were compatible with the fact that the TP82-induced intracellular Ca2+ increase was largely dependent on the secondary effect of thromboxane A2. These findings may be clues to explain the marked difference in the Ca2(+)-response characteristics between the fluorescent indicators and aequorin as well as the properties of TP82-induced platelet activation.
通过钙敏感光蛋白水母发光蛋白以及钙敏感荧光团fura 2和quin 2监测由CD 9单克隆抗体TP82触发的人血小板中的细胞质钙动员。水母发光蛋白指示的钙值与TP82的浓度成正比，而TP82的浓度与血小板聚集和5-羟色胺释放开始前的延迟时间成反比。当fura 2用作钙指示剂时，高于阈值浓度，即使浓度增加，TP82诱导的细胞内钙值仍保持不变。用quin 2获得的结果与TP82诱导的细胞内钙增加很大程度上依赖于血栓素A2的继发效应这一事实相符。这些发现可能是解释荧光指示剂与水母发光蛋白之间钙反应特性的显著差异以及TP82诱导的血小板活化特性的线索。
