EFFECTS OF QUERCETIN ON AGGREGATION AND INTRACELLULAR FREE CALCIUM OFPLATELETS

AIM: To study the effects of Que on the intraplatelet free calcium con centration and the effects of calcium on the inhibition of platelet ag gregation by Que. METHODS: Using Quin-2 fluorescence technique. RESULT S: Que inhibited the platelet aggregation and the rise of [Ca2+]i indu ced by thrombin in platelets. The values of IC50 and 95 % confidence i nterval were 146.2 (92.4-231.3) and 78.5 (49.5-124.4) mu mol . L(-1) r espectively. The inhibitory effects of Que on platelet aggregation ind uced by thrombin were reduced by adding calcium to the medium, and Que had no effect on thrombin-induced internal Ca2+ release from dense tu bular system. CONCLUSION: The inhibitory effects of Que on aggregation and the rise of [Ca2+]i in platelets was mainly due to an inhibition of Ca2+ influx.