Abstract: AIM: To study the effects of aspirin-ni-acinamide-zinc complex (WUY) on platelet aggregation and experimental thrombosis.METHODS: With ade-nosine diphosphatethe (ADP), arachidonic acid (AA) and collagen, the effectsof aspirin-niacinamide-zinc com-plex (WUY) on platelet aggregation in vitro or in vivo were investigated by Born'smethod.The mouse mortality caused by intravenous injection of AA and experimental thrombus formation in rats were observed.Radioimmuno-assay was used for measuring thromboxane B₂ (TXB₂) and 6-keto-PGF_1αin plasma of rabbits.RESULTS: In high, middle and low dose groups, drugs, in vitro, inhibited ADP-, AA-and collagen-induced platelet aggregation and the effect of WUY was stronger than that of ASP in high dose groups.In vivo, WUY showed more potent inhibito-ry effects on AA-induced aggregation in 1 h and 3 h. WUY had a powerful inhibitory effect on mouse death as a result of pulmonary thrombi induced by AA injection into the tail vein and ED₅₀ was lower than that of ASP. In ad-dition, WUY exhibited strong inhibitory effect on throm-bus formation in rat arteri-venous shunt and significantly reduced plasma level of TXB₂ while it markedly increasing 6-keto-PGF_1α in high dose groups and ASP significantly reduced plasma level of both TXB₂ and 6-keto-PGF_1α. CONCLUSION: The effect of WUY on platelet aggrega-tion and experimental thrombosis is stronger than that of ASP and can increase plasma level of 6-keto-PGF_1α.

Key words: aspirin-niacinamide-zinc complex, aspi-rin, platelet aggregation, thrombosis, TXB₂, 6-keto-PGF_1α