摘要
本工作探讨血小板致密颗粒(dG)和α颗粒(αG)是否是细胞内钙库。在快速冷冻超薄切片上用电镜X射线显微分析法测定dG和αG的钙含量,分别为30.12±3.45和27.39±2.76 mmol/kg,证实含高钙。用磷钨酸乙醇(EPTA)染色的切片测得其钙含量分别为18.21±2.66和12.51±1.29 mmol/kg,说明钙有部分丢失。用激动剂A23187、凝血酶和ADP引起血小板变形时,两种颗粒的数密度明显下降,在EPTA染色切片上测出两种颗粒的钙进一步下降,下降幅度显著(P<0.01)。以上结果说明:1,血小板αG和dG皆含有高钙,是细胞内钙库,当分泌活动增强,颗粒数减少时,伴有颗粒钙释放;2,EPTA染色切片比冷冻切片的制备简便,适于颗粒钙含量变化的研究。
This work aimed at exploring whether the dense granule (dG)and the a granule (aG)in blood platelets are the intracellular calcium store. In rapidly frozen ultrathin cryosections the Ca content of the dG and the aG were 30.12±3.45(n=40)and 27.39±2.79(n=34)mmol/kg respectively measured by electron microscopic X-ray microanalysis. The high Ca concentration of the two kinds of granules was proved. In ethanolic phosphotungstic acid (EPTA) staining sections,the Ca content of dG was 18.21±2.66 (n=32)and that of aG was 12.51±1.29 (n-17)mmol/kg. It means that the Ca content has been lost during the preparation of the sections. When the agonist of A23187(1μmol/L),or thrombin(2U/ml)or ADP(200μmol/L)was added to the platelet rich plasma to activated platelets,the numerical density(Nv)of both aG and dG was decreased prominently. Concurrently,the Ca content of both the granules measured in EPTA staining sections was decreased significantly(p<0.01). Therefore,following suggestions can be made from these findings. 1,The 1aG and dG of blood platelets might be an intraeellular Ca store,because of their high Ca content. 2,The Nv and Ca content of both granules decreased concomitantly when platelets were activated by agonists. It might indicate that an increase in granule secretion accompanys Ca releasing from the granules. 3,The preparation of EPTA staining sections is easier than that of ultrathin cryosections. Although the EPTA preparation loses somewhat Ca content,the EPTA staining sections can be used to investigate the alteration in granule Ca content of platelets activated by agonists.
出处
《电子显微学报》
CAS
CSCD
1996年第2期301-306,共6页
Journal of Chinese Electron Microscopy Society
基金
国家自然科学基金(39370207)
关键词
血小板激活
α颗粒
颗粒数
钙含量
blood platelet a granule dense granule numerical density Ca content
