Alpha-4 beta-2 nicotinic acetylcholine receptor (α4β2 nAChR) (α4β2 nAChR)

The alpha-4 beta-2 (α4β2) nicotinic acetylcholine receptor is a predominant subtype of ligand-gated ion channel in the mammalian central nervous system, characterized by its high affinity for nicotine (Gotti et al., 2006, Progress in Neurobiology). It typically assembles as a heteropentamer of α4 and β2 subunits, with the (α4)2(β2)3 stoichiometry being the most common high-affinity form (Albuquerque et al., 2009, Physiological Reviews). This receptor is a major regulator of neurotransmission, particularly modulating dopamine release in the mesolimbic pathway, which makes it a primary mediator of the reinforcing effects of nicotine and a central target for smoking cessation therapies (Changeux, 2010, Nature Reviews Neuroscience; Rollema et al., 2007, Neuropharmacology). Beyond addiction, α4β2 receptors are essential for cognitive functions such as attention and working memory, and their decline is associated with neurodegenerative conditions like Alzheimer's and Parkinson's diseases (UniProt P43681, P17677). Mutations in the genes encoding these subunits (CHRNA4 and CHRNB2) are also linked to specific forms of hereditary epilepsy, such as Autosomal Dominant Sleep-Related Hypermotor Epilepsy (StatPearls, 2023). Pharmacologically, the receptor is targeted by a variety of agonists, antagonists, and allosteric modulators to treat addiction and cognitive impairment, though achieving subtype selectivity remains a challenge to minimize peripheral side effects.

Other names

α4β2* nicotinic acetylcholine receptorNeuronal acetylcholine receptor subunit alpha-4/beta-2 complexCHRNA4/CHRNB2 receptorHigh-affinity nicotinic receptor

The receptor functions as a pentameric ligand-gated ion channel that opens upon binding of acetylcholine or exogenous agonists like nicotine. This opening allows the influx of cations (primarily Na+ and Ca2+) and efflux of K+, leading to membrane depolarization and the activation of voltage-gated calcium channels, which subsequently triggers the release of neurotransmitters such as dopamine, GABA, and glutamate (Albuquerque et al., 2009, Physiological Reviews). Drugs like varenicline act as partial agonists, providing enough stimulation to ease withdrawal while competitively inhibiting the full agonist effects of nicotine (Rollema et al., 2007, Neuropharmacology).