Effect of thromboxane synthetase inhibitors (OKY-046, OKY-1580) on experimentally induced air embolism in anesthetized dogs.

We investigated the effects of OKY-046 and OKY-1580, thromboxane A2 (TxA2) synthetase inhibitors, on plasma levels of 6-keto PGF1 alpha and TxB2 in anesthetized dogs with experimentally induced air embolism. The percentage increase of tracheal pressure induced by room air infusion was suppressed significantly by premedication with OKY-046. The percentage increase of pulmonary artery blood pressure was suppressed significantly by premedication with OKY-046 compared to that in control group. By room air infusion after the premedication with OKY-046 and OKY-1580, systemic artery blood pressure did not show any significant changes. Plasma 6-keto PGF1 alpha level showed a marked increase by an intravenous infusion of room air, and such an increase became more predominant by the premedication with OKY-046 and OKY-1580. On the other hand, plasma TxB2 level showed a marked increase by an intravenous infusion of room air, and such an increase became less predominant by the premedication with OKY-046 and OKY-1580. These results may suggest that OKY-046 and OKY-1580 are not only TxA2 synthetase inhibitors but also PGI2 synthetase accelerators and are useful drugs for treatment and prevention of thromboembolism.