PGD2 induces pulmonary hyperresponsiveness to acetylcholine in vivo in the guinea-pig

1 A threshold dose of Prostaglandin D2 (PGD2) (0.5 microgram/kg i.v.), which did not modify the basal values of airway resistance, potentiated the acetylcholine induced bronchospasm in anaesthetized guinea-pigs. 2 beta-adrenoreceptors blockade induced by propranolol enhanced the positive interaction between PGD2 and acetylcholine in the pulmonary dynamics. 3 Active sensitization of guinea-pigs by ovalbumin increased the pulmonary PGD2-acetylcholine interaction and the phenomenon was sustained during the time. 4 The inability of PGD2 to potentiate histamine-induced bronchoconstriction suggests a specificity for the interaction.