Alpha-4-beta-2-alpha-5 nicotinic acetylcholine receptor (α4β2α5 nAChR)

The alpha-4-beta-2-alpha-5 nicotinic acetylcholine receptor is a specialized subtype of pentameric ligand-gated ion channels located predominantly in the mammalian central nervous system (UniProt: P43681, P17645, P30532). It is characterized by the assembly of alpha-4 and beta-2 subunits, which form the orthosteric binding sites for acetylcholine and nicotine, along with the alpha-5 accessory subunit (PubMed: 21278793). The incorporation of the alpha-5 subunit is known to modulate the receptor's functional profile, specifically increasing calcium permeability and altering the rate of desensitization compared to the standard alpha-4-beta-2 receptor (PubMed: 25635043). This receptor subtype is highly expressed in the ventral tegmental area and is a key mediator of the reinforcing effects of nicotine through the modulation of dopamine release (Nature: 471, 225–229). Genetic polymorphisms in the CHRNA5 gene, which encodes the alpha-5 subunit, have been robustly linked to increased susceptibility to nicotine dependence and a higher risk of developing lung cancer (NIH: rs16969968). Therapeutic strategies targeting this receptor include the use of partial agonists like varenicline and cytisine, which help reduce withdrawal symptoms and block the rewarding effects of smoking (StatPearls: NBK534846). Research also suggests that these receptors may be involved in cognitive functions and could serve as targets for treating neurodegenerative diseases such as Alzheimer's (PubMed: 16258071).

Other names

Alpha4beta2alpha5 nicotinic receptorCHRNA4/CHRNB2/CHRNA5 receptorα4β2α5 nAChRNeuronal acetylcholine receptor subunit alpha-4/beta-2/alpha-5

Agonism or partial agonism at the nicotinic acetylcholine receptor leads to the opening of a cation-selective pore, resulting in cellular depolarization and the subsequent release of neurotransmitters such as dopamine (PubChem: CID 5311).