Overview Neuronal classification based upon the type of neurotransmitter they release and which inhibitor acts on them cholinergic: acetylcholine (ACh) inhibitors muscarine (M) nicotinic (N) adrenergic: epinephrine (Epi) noradrenergic: norepinephrine (NE) dopaminergic: dopamine (D1 and D2) Central Nervous System (CNS) = brain and spinal cord Autonomic: controls activities NOT under direct conscious control parasympathetic (ACh M) cardiac muscle smooth muscle nerve terminals gland cells sympathetic cardiac muscle (NE) smooth muscle (NE) sweat glands (ACh M) gland cells (NE) renal vascular smooth muscle (D1) nerve terminals (NE) Somatic (ACh N): controls activities under direct conscious control (movement and respiration) skeletal muscle ACh receptors Nicotinic ACh receptors ligand-gated Na+/K+ channels 2 subtypes NN found in the preganglionic efferent fibers synapsing in the autonomic ganglia NM found in the somatic motor fibers synapsing on neuromuscular junction Muscarinic ACh receptors G-protein coupled receptors 5 subtypes M1 M2 M3 M4 M5