It has been reported that trapidil inhibits the thromboxane-A2 synthesis in platelet and promotes the prostacycline synthesis in vascular endothelium in vitro studies. However, it is not clear whether or not trapidil has the antithrombotic effect in vivo. This study was undertaken to make clear the antithrombotic effect of trapidil. After oral administration of 300mg per day of trapidil for 2-4 weeks, platelet adhesion and aggregation, plasma level of β-thromboglobulin (β-TG) and HDL-cholesterol and coagulation activities were measured. The following results were obtained from these studies.
1) Both rate of platelet adhesion and maximum aggregation rate of platelet aggregation induced by ADP (47×10-6M) were reduced significantly compared with the value before administration. Furthermore, a significant decrease in plamsma β-TG level was recognized. (p<0.05).
2) There were no chage in coagulation activities before and after administration of trapidil.
3) Plasma HDL-cholesterol level showed a significant increase after administration of trapidil. These results suggest that in vivo platelet activation in vascular system could be inhibited by trapidil.
