muscarinic agonist muscarinic agonist a muscarinic agonist is an agent that activates the activity of the muscarinic acetylcholine receptor. the muscarinic receptor has different subtypes, labelled m1-m5, allowing for further differentiation. muscarinic agonistdrug classskeletal structor formula of muscarineclass identifiersatc coden07biological targetmuscarinic acetylcholine receptor