Methacholine
Methacholine is a quaternary ammonium ion in which the nitrogen is substituted with three methyl groups and a 2-acetoxypropyl group. Parasympathomimetic bronchoconstrictor drug used in clinical diagnosis. It has a role as a muscarinic agonist, a bronchoconstrictor agent, an epitope, a cholinergic agonist and a vasodilator agent. It is a quaternary ammonium ion and an acetate ester.