Nicotinic ACh receptors are ligand-gated Na⁺/K⁺ channels. - N_N (found in autonomic ganglia, adrenal medulla) - N_M (found in neuromuscular junction of skeletal muscle)

Muscarinic ACh receptors are G-protein-coupled receptors that usually act through 2nd messengers.- M_1-5 found in heart, smooth muscle, brain, exocrine glands, and on sweat glands (cholinergic sympathetic)