Inhibitory effects of procainamide on rabbit platelet aggregation and thromboxane B2 production in vitro.

AIM: To study the influences of procainamide (PA) on thrombin-induced rabbit platelet aggregation and thromboxane B2 (TXB2) production in vitro. METHODS: Turbidimetry and radioimmunoassay were used. RESULTS: PA 8.5, 34, 136, and 544 mumol.L-1 inhibited thrombin-induced platelet aggregation and TXB2 production, and the inhibitory rates were 45% +/- 37%, 48% +/- 32%, 88% +/- 23%, 92% +/- 15% and 53% +/- 24%, 65% +/- 26%, 90% +/- 6%, 95% +/- 6%, respectively. There was positive correlation between PA concentration and efficiency of inhibition of platelet aggregation and TXB2 production, and also between the inhibition % of platelet aggregation and that of production of TXB2. The three linear equations and main parameters were Y = 0.2075X-4.9157, r = 0.9985; Y = 0.9546X-34.6724, r = 0.9921; Y = 0.8202X + 19.7062, r = 0.9921. CONCLUSION: PA inhibited thrombin-induced platelet aggregation and TXB2 production in rabbits.