Antithrombotic effect of L-arginine in hypertensive rats

The aim of the study was to evaluate the effect of L-arginine (L-Arg) on haemostasis in stasis model of venous thrombosis in renal hypertensive rats. The effect of the single dose (i.v. 300 mg/kg bolus+300 mg/kg/h) and of the 10-day application (p.o. 1 g/kg, once daily) of L-Arg was determined. L-Arg reduced the blood pressure both in the acute and long-term application. The single dose of L-Arg decreased the occurrence rate of the thrombus whereas long-term administration reduced significantly the thrombus weight. There were no differences in prothrombin time and activated partial thromboplastin time while the fibrinogen concentration decreased both in the acute and the long-term experiment. L-Arg shortened euglobulin clot lysis time and bleeding time in the long-term application. The chronic L-Arg treatment also inhibited significantly collagen-induced platelet aggregation. The overall haemostasis and coagulation potentials were inhibited and the fibrinolysis potential was higher in the group receiving this amino-acid. The results show that L-Arg, in a complex way, evokes the antithrombotic effect in the model of venous thrombosis in hypertensive rats.