Evidence against leukotriene-mediation of propranolol-induced airway hyperreactivity to acetylcholine.

In unanaesthetized guinea-pigs, propranolol treatment (0.1 mg kg-1 i.v.) substantially increased reactivity to intravenous acetylcholine infusion or aerosolized histamine to a comparable degree. Neither BW755c (5 mg kg-1 i.v.), FPL 55712 (1 mg kg-1 i.v.), nor piriprost (5 mg kg-1 i.v.) pretreatment influenced propranolol's effect on muscarinic reactivity although BW755c abolished histaminic hyperreactivity. This suggests that propranolol-induced muscarinic hyperreactivity in the guinea-pig is not mediated by leukotrienes whereas histaminic hyperreactivity may be.