Neuronal acetylcholine receptor subunit alpha-5 (α5 nAChR subunit)

The neuronal acetylcholine receptor subunit alpha-5 is an accessory subunit of heteropentameric nicotinic acetylcholine receptors, encoded by the CHRNA5 gene. Unlike other α or β subunits that compose the primary ligand binding interfaces, α5 does not form functional channels by itself but co-assembles (primarily) with α4, β2 or α3, β4 subunits to modify receptor properties. This subunit markedly alters receptor trafficking, surface expression, ion channel permeability (especially to Ca²⁺), ligand sensitivity, and intracellular signaling, including G protein coupling. Genetic variation in CHRNA5 is robustly linked to increased risk for nicotine dependence, some cancers, COPD, and vascular diseases. α5-containing nAChRs are expressed throughout the CNS and PNS, with distinct functional roles in modulating synaptic transmission, neurotransmitter release, and neuronal excitability. Drugs targeting these receptors include agonists (nicotine, varenicline) and selective antagonists/inhibitors like DhβE and epibatidine

Other names

Cholinergic receptor nicotinic alpha 5 subunitCHRNA5 (gene name)nAChR α5α5 subunit

Agonists (e.g., nicotine): activate nAChRs containing α5, resulting in cation influx and neuronal excitation. Antagonists/inhibitors (e.g., DhβE): block acetylcholine/nicotine-induced responses by inhibiting receptor activation.