Effects of oxyfedrine on platelet thromboxane A2 and aorta prostacyclins formations

The effects of oxyfedrine (Oxy) and aspirin on generation of rabbits platelet thromboxane A2 (TXA2) and rats aorta prostacyclins (PGl2) were studied. Oxy inhibited rabbit platelet aggregation induced by AA in vitro. The production of TXB a stable metabolite of TXA2, released from rabbits platelet was determined by RIA. Oxy 135 and 270 vg/ml signiicantly inhibited TXB2 formation in vitro. After iv Oxy 3.0 mg/kg, TXB9 contents in platelet were significantly reduced at 5,15 and 30 min. Oxy 270 g/ml decreased the formation of PGI2-Iike substances in rat aorta ring in vitro. However, in case of iv Oxy 3.0 mg/kg. PGl2-Iike substances and 6-keto-PGF10 contents in rats plasma and artery were not inhibited. In contrast, aspirin decreased these contents both in vitro and in vivo markedly. These results suggest that the anti-aggregation of Oxy may be related to the inhibition of platelet TXA2 formation.