The bronchodilator acitivity of an 11-deoxyprostaglandin (AY 23 578)

The bronchodilator activity of AY-23 578 was studied in vivo and in vitro techniques. In the conscious guinea pig, aerosols of AY-23 578, prostaglandin (PGE2) E2, and isoproterenol afforded significant protection against histamine-induced convulsions. In the anesthetized guinea pig, where changes in tracheal pressure were taken as an index of bronchoconstriction, AY-23 578, PGE2, and isoproterenol were equipotent in inhibiting the bronchoconstriction induced by histamine. AY-23 578, PGE2, and isoproterenol reduced or prevented neostigmine-, prostaglandin F2alpha- or carbachol-induced increases in pulmonary resistance, and decreases in dynamic compliance in the anesthetized cat. The activities of the former two compounds were qualitatively similar but less potent than isoproterenol. In both the guinea pig and the cat, the aerosol administration of effective bronchodilator doses of AY-23 578 did not exhibit any significant cardiovascular effects. Both AY-23 578 and PGE2 caused relaxation of the isolated guinea pig tracheal strip; PGE2 was about six times more potent than AY-23 578. It is concluded that AY-23 578 is an effective bronchodilator in both the guinea pig and cat.