- Cholinergic Antagonists are compounds that bind to the nicotinic or muscarinic acetylcholine receptors but do not cause activation of the usual intracellular signaling pathways. Sufficient structural diversity exists among different cholinergic receptors that antagonistic drugs display specificity between muscarinic and nicotinic receptors. Furthermore, nicotinic receptors at autonomic ganglia and the neuromuscular junction are sufficiently different that drugs exist that antagnoize each specifically. Consequently, three basic classes of cholinergic antagonists exist, each resulting in distinct pharmacological effects: Muscaranic Receptor Antagonists, Ganglionic Blockers, and Neuromuscular Blockers. Muscarinic receptor antagonists are the most clinically important drug class as the ganglionic and neuromuscualar blockers are only used in specialized scenarios.