Prostacyclin and thromboxanes in carrageenan-induced pleurisy in the rat

Abstract

The cellular origin and kinetics of TXB₂ and 6-keto PGF_1α in carrageenan-induced pleurisy has been studied. Maximum levels of these prostanoids occurred 1 hour after induction of pleurisy. Mononuclear cells initially present in the pleural cavity synthesized TXB₂ and 6-keto PGF_1α from (¹⁴C) arachidonic acid. By contrast, PMN cells harvested 6 hours after the induction of inflammation did not produce 6-keto-PGF_1α. Selective inhibition of thromboxane synthetase with drugsin vitro andin vivo increased the formation of 6-keto-PGF_1α, the stable breakdown product of PGI₂. This metabolic effect was parallel to an increase in the volume of exudate and in PMN migration. These results suggest that TXA₂ seems to be implicated not only as a chemotactic agent but also as an antagonist of PGI₂ vasodilator effects.