[Inhibition of platelet function by L-arginine.L-aspartate salt]

The effects of L-arginine.L-aspartate salt (DR) on platelet aggregation, adhesion and release were investigated. Platelet aggregation induced by adenosine 5 -diphosphate (ADP) was significantly inhibited (P<0.01) by intravenous injection of DR (15 mg/kg) in rats or oral administration (15 mg/kg) in rabbits, the inhibitory effect on rabbit platelet aggregation lasting for more than 8 h (P<0.01). Platelet aggregation induced by ADP, collagen or thrombin in rats was all markedly inhibited by 7.5, 15 or 30 mg/kg of DR (bid for 3.5 d, ig, P<0.01). Platelet adhesion to foreign objects was inhibited by 30 mg/kg of DR (ig). Bleeding time in rat tails was prolonged by 30 mg/kg of DR (P<0.05). Furthermore, PGI(2) released from the vascular wall was increased in DR-treated rats (P<0.05), however, TXA(2) released from platelets was not affected. These data demonstrate the inhibitory effect of DR on platelet function, suggesting that its action target may be different from that of acetylsalicylic acid, and that the increase of PGI(2) release may be responsible partly for this effect. It is suggested that DR may probably be used as a new agent for regulating platelet function.