川芎嗪对血小板中肌醇磷脂和2OK蛋白质磷酸化的抑制作用

Inhibition of tetramethylpyrazine on the phosphorylation of phosphoinositide and 20K protein in platelets

在Mg^(2+)存在下.用血小板膜与(γ—^(32)P)ATP保温,以观察川芎嗪对^(32)P掺入磷脂和蛋白质的影响,结果表明:血小板膜中存在磷脂酰肌醇(PI)激酶和磷脂酰肌醇—4—磷酸(PIP)激酶,而胞浆中缺乏或极少;ATP促进肌醇磷脂磷酸化;川芎嗪抑制血小板中PIP和20K蛋白质的磷酸化.半数抑制浓度分别为40μmol·L^(-1)

Thrombocytic membranes were incubated with [μ-32P] ATP in the presence of Mg2+ to observe the effect of tetramethylpyrazine on incorporation of 32 P into phospholipids and proteins. The result showed there are phosphatidylinositol kinase and phosphatidylinositol 4 - phosphate kinase in platelet membranes, while almost none or very little in cytosol. ATP stimulated the phosphory-lation of phosphoinositides. Tetram- ethylpyrazine inhibited the phosphoryla-tion of phosphatidylinositol 4-phosphate and 20K protein in platelets. Concentrations giving 50% inhibition (IC50) were 40 μmol · L-1 and 110 μmol · L-1 respectively. The data might be valuable in clarifying the antiplatelt mechanism of tetramethylpyrazine.