绞股蓝总皂甙对家兔血小板聚集释放及cAMP水平的影响

Effects of gypenosides on platelet aggregation release and cAMP level in rabbits

本文研究了绞股蓝总皂甙对家兔血小板聚集、5—羟色胺释放及血小板内cAMP含量的影响.结果发现绞股蓝总皂甙在体内和体外均明显抑制二磷酸腺苷,花生四烯酸和胶原诱导的血小聚集;抑制血小板5—羟色胺的释放;升高血小板内cAMP的水平.效应与剂量间呈现依赖关系.提示绞股蓝总皂甙为一血小板功能抑制剂,作用机理可能与其升高血小板内cAMP的水平,抑制血小板释放活性物质有关.

The antiplatclet aggregation effect of gypenosides(GPs)extracted from Gynoslemma pentaphyllun(Thnb.)Mak.was studied in platelet-rich plasma(PRP)of the rabbit by Bern's turbidometry.GPs inhibited platelet aggregation induced by threshold concentration of ADP,arachidonic acid and collagen in a dose-dependent manner in vitro and IC50 was about 0.49,0.47 and 0.50mg/ml,respectively.GPs(40 mg/kg)also inhibited platelet aggregation in vivo,approximately lasting for 60 min and its maximal inhibition rate for ADP,arachidonic acid and collagen was 32.6,39.6 and 35.7%,respectively.The most powerful action occured at 5 min after giving GPs.In order to study its antiplatelet mechanism,effects of GPs on platelet serotonin release and cAMP level were further studied in PRP of therabbit by fluorescence spcctrophotomctry and in washed platelet suspension of the rabbit by radioimmunoassay,respectively.GPs and aspirin both inhibited platelet serotonin release induced by collagen with inhibition rate of 87.1 and 91.7% at 1.00 mg/ml,respectively.GPs also significantly increased the platelet cAMP level,with increasing rate of 200% at 1.00 mg/ml.The results suggest that GPs is a potent inhibitor to platelet aggregation and its action mechanism may related to inhibiting the platelet from releasing reaction and increasing the platelet cAMP level