THE ANTITHROMBOTIC EFFECT OF LOW-MOLECULAR-WEIGHT SYNTHETIC THROMBIN INHIBITORS, ARGATROBAN AND PPACK, ON HE-NE LASER-INDUCED THROMBOSIS IN RAT MESENTERIC MICROVESSELS

The antithrombotic effect of low molecular weight synthetic thrombin inhibitors, argatroban ((2R, 4R)-4-methyl-1-[N2-[(3-methyl-1, 2, 3, 4-tetrahydro-8-quinolinesulfonyl)-L-arginyl]-2-piperidinecarboxylic acid monohydrate]) and PPACK (D-phenylalanyl-L-prolyl-L-arginyl-chloromethyl ketone) on He-Ne laser-induced thrombosis in rat mesenteric microvessels was studied. Both inhibitors showed a significant antithrombotic effect at 0.5 mg/kg which lasted for 50 min and 50-60 min using argatroban and PPACK, respectively. A dose-dependent effect was observed in arterioles and venules. The results suggest that thrombin plays an important role in the formation of a platelet thrombus in vivo.