[Effects of thromboxane A2 synthetase inhibitor, DP-1904 on the action of vasoactive substances in guinea pig trachea and lung tissue strips].

Thromboxane A2 (TxA2) is a potent platelet aggregator and vascular or bronchial constrictor. DP-1904, a newly synthesized imidazol TxA2 synthetase inhibitor, is a potent and long-acting agent. The present investigation was conducted to explore the effect of DP-1904 on the contractile or relaxing responses in guinea pig trachea and lung tissue strips induced by various vasoactive substances. Fourteen guinea pigs, weighing 300-350 g, were sacrificed. Trachea and lungs were removed, cut spirally, set up in bioassay glass jackets and superfused with Krebs-Henseleit solution at 37 degrees C, saturated with oxygen and carbon dioxide. Contraction of tissues was detected by an isotonic transducer and displayed on a polyrecorder. Arachidonic acid-induced relaxing responses in guinea pig trachea strips were attenuated significantly by the continuous infusion of DP-1904 in a dose-dependent fashion. Arachidonic acid-induced contractile responses in guinea pig lung strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. Acetylcholine-, histamine- and prostaglandin F2 alpha-induced contractile responses in guinea pig lung and trachea strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. The above results suggest that DP-1904 might be a useful therapeutic agent for the treatment of chronic obstructive lung diseases.