A study on the effects of cyclo-oxygenase and thromboxane synthetase inhibitors on right atrial prostacyclin and thromboxane A₂ levels

Abstract

The right atrial tissues obtained at the time of coronary bypass surgery were studied for release of prostacyclin and thromboxane. Human, right atrial tissues are capable of producing thromboxane A₂ (TXA₂) in addition to prostacyclin. Indomethacin and Aspirin by inhibiting generation of cyclic endoperoxides inhibited synthesis of both prostacyclin and TXA₂ In contrast a thromboxane synthethase inhibitor U63557A selectively inhibited TXA₂ without significant effects on prostacyclin synthesis. The study points to the superiority of thromboxane synthetase inhibitor U63557A over Aspirin or Indomethacin and represents an important approach to platelet inhibition by selectively inhibiting thromboxane synthesis without affecting the synthesis of prostacycline.