Methacholine Chloride

Methacholine chloride is a quaternary ammonium parasympathomimetic agent with the muscarinic actions of acetylcholine. It is hydrolyzed by ACETYLCHOLINESTERASE at a considerably slower rate than ACETYLCHOLINE and is more resistant to hydrolysis by nonspecific CHOLINESTERASES so that its actions are more prolonged. It is used as a parasympathomimetic bronchoconstrictor agent and as a diagnostic aid for bronchial asthma. (In Vivo) :Methacholine choride (0.5 μg/kg plus 5 μg/kg/min for 30 min) induces bronchoconstriction in dogs.Methacholine choride (0.5 mg/kg; i.v.) induces bronchoconstriction was inhibited by bradykinin (4-40 μg/kg; i.v.) in a a dose-dependent manner in mouse.