血小板激活时胞质游离钙浓度与两种颗粒数变化的相关性

THE RELATIONSHIP BETWEEN CYTOSOLIC Ca^(2+) AND TWO KINDS OF GRANULE NUMBER IN ACTIVATED PLATELETS

用电镜形态计量法检测血小板α颗粒（αG）和致密颗粒（dG）的数密度，用钙荧光指示剂Fura2检测血小板胞质游离Ca2+浓度（[Ca2+]i），观察到在钙离子导体A23187作用下，血小板[Ca2+]i明显升高。凝血酶与ADP也都分别引起[Ca2+]i升高，且有浓度依赖性。选用三种激动剂的不同量以反映血小板不同程度激活时，测定[Ca2+]i与颗粒数密度，分析两者间的相关性，发现αG和dG的数密度都与[Ca2+]；有紧密的相关性（Pr（αG）＜0．05，pr（dG）＜0.01），说明血小板的[Ca2+]i升高可促进αG和dG内容的分泌。

The numerical density (Nv) of the α-granule (αG) and dense grantile (dG)measured by using electron dricroscopic morphometry and the cytosolic free calcium concentration ([ Ca2+]i) by using Ca-fluorescent indicator were observed for studying the relationship of [ Ca2+]i and Nv of αG and dG in platelets activated by A23187, thrombin or ADP. The results showed that the [Ca2+]i rose markedly by A23187. Thrombin or ANP could also induce an increase of [Ca2+]i concentration-dependently. Under 3 different degrees of activation induced by different agonists,the close relationship between Nv of both granules, αG and dG, and [Ca2+]i in platelets was found (Pr(αG) < 0.05,Pr(dG) <0.01). These findings indicate that the increase in [Ca2+]i may enhance the secretion of αG and dG.