PREVENTION BY THE TACHYKININ NK2 RECEPTOR ANTAGONIST, SR-48968, OF ANTIGEN-INDUCED AIRWAY HYPERRESPONSIVENESS IN SENSITIZED GUINEA-PIGS

The involvement of tachykinins in antigen-induced airway hyperresponsi veness (AHR) was characterized pharmacologically in guinea-pigs sensit ized to ovalbumin with antagonists of tachykinin NK1 and NK2 receptors , namely SR 140333 and SR 48968, respectively. AHR was illustrated by increased sensitivity to bronchoconstriction provoked by aerosolized a cetylcholine in anaesthetized, ventilated animals, administrated 48 h after ovalbumin aerosol challenge. SR 48968 (1 mg kg(-1), i.p.), when given once 30 min before the antigen challenge, prevented AHR, whereas SR 140333 did not. These findings suggest that the tachykinin NK2 rec eptor antagonist, SR 48968, may be useful for investigating mechanisms of tachykinins in the development of airway hyperresponsiveness.