Category: biosynthesis
ACh synthesis: choline + acetyl-CoA → acetylcholine (CHOLINE ACETYLTRANSFERASE, ChAT — cholinergic neuron marker). Released into synapse, binds nicotinic (NMJ + ganglia + CNS) and muscarinic (M1-M5 — autonomic + CNS) receptors. Rapid hydrolysis: ACh → choline + acetate (ACETYLCHOLINESTERASE, AChE — postsynaptic NMJ + RBCs). Plasma butyrylcholinesterase (BChE / pseudocholinesterase) is a related enzyme — succinylcholine + mivacurium hydrolyzed here. Cholinesterase inhibitors: reversible (DONEPEZIL / rivastigmine / galantamine for Alzheimer; PYRIDOSTIGMINE / neostigmine for myasthenia gravis + NMJ reversal); irreversible (organophosphates — sarin, VX, malathion; pralidoxime + atropine for poisoning). BChE-deficient phenotypes have prolonged paralysis with succinylcholine (the classic "succinylcholine apnea" complication).