The bronchodilator activity of 20-isopropylidene prostaglandin E2 (CS-412)

The bronchodilator activity of 20-isopropylidene prostaglandin E2 (CS-412) was studied in vivo. In the conscious guinea pig, aerosols of CS-412, prostaglandin E2 (PGE2), or salbutamol afforded similar protection against histamine-induced convulsions. In the anesthetized guinea pig, where increase in intratracheal pressure was taken as an index of bronchoconstriction, CS-412, PGE2, and salbutamol were equipotent in inhibiting the broncho-constriction induced by histamine. CS-412, PGE2 and salbutamol were equally effective in reducing the serotonin-induced increase in pulmonary resistance in the anesthetized cat. CS-412 was different from PGE2 in bronchoconstrictor activity in anesthetized cats with normal bronchotonus. PGE2 caused bronchoconstriction in the cats. CS-412 showed 30 times less constrictor activity than PGE2. It was concluded that CS-412 is an effective bronchodilator without unfavorable side effects.