EFFECTS OF QUERCETIN ON PLATELET AND REPERFUSION-INDUCED ARRHYTHMIAS IN RATS

The role of platelets in reperfusion arrhythmias (RA ) and the efficac y of quercetin (Que) in preventing the arrhythmias were investigated i n anesthetized rats. Platelet count (PC) was performed, the ultrastruc ture of platelets was scrutinized , and the levels of thromboxane B2 ( TXB2) and 6-ketoprostaglandin F1 alpha (Keto-PGF1alpha) in plasma were determined by radioimmunoassay (RIA ). The pretreatment with Que (5 m g-kg-1) 2 min prior to reperfusion inhibited RA. Que remarkably improv ed the ultrastructural deviation of platelet, inhibited the platelet a ggregation and thromboxane A2(TXA2) formation, and increased the prost acyclin (PGI2) generation and the ratio of PGI2/TXA2. The decrease in PC and increase in TXB2 level in plasma indicated the participation of platelets in the arrhythmogenic activity of ischemia and reperfusion. The results showed that Que produced a protective effect against RA p robably through inhibiting the platelet aggregation, TXA2 formation an d increasing the PGI2 generation.