TRIFLAVIN, AN ARG-GLY-ASP-CONTAINING PEPTIDE, PREVENTS PLATELET PLUG FORMATION IN IN-VIVO EXPERIMENTS

Triflavin, an Arg-Gly-Asp-containing peptide from Trimeresurus flavovi ridis snake venom (M(r) of 7500 Da) inhibits platelet aggregation thro ugh the blockade of fibrinogen binding to activated platelets. The pre sent study demonstrated that the intravenous injection of triflavin (0 .1 and 0.25 mg/kg) significantly prolonged the bleeding time about 1.8 - to 2.4-fold as compared with control (normal saline) of severed mese nteric arteries in rats, whereas the injection of Gly-Arg-Gly-Asp-Ser (GRGDS) (2-8 mg/kg) failed to increase the bleeding time in this model . Continuous infusion of triflavin (0.08 mg/kg/min) significantly incr eased the bleeding time about 2.6-fold, and the bleeding time returned to normal within 20 min after the cessation of triflavin infusion. Tr iflavin (10-20 mg/kg) significantly prolonged the occlusion time of pl atelet plug formation induced by irradiation of mesenteric venules of fluorescein sodium-pretreated mice. In contrast, trigramin (10-20 mg/k g) and GRGDS (500 and 1000 mg/kg) showed no significant effect. These results suggest that triflavin has an effective antiplatelet effect in vivo and this peptide may be a useful therapeutic agent for arterial thrombosis.