<prompt> Methacholine has maximum agonist action at which of the following cholinergic receptors?M1M2M3M4  <response>: Methacholine is a non selective muscarinic agonist. It has maximum agonist action on M2 receptor Relative Lee selective agonist of cholinergic receptor are: M1 selective: Oxotremorine M2 selective:metha methach ME selective: bethanechol Ref- katzung 12e p100; KDT 7e p101 