Neuronal acetylcholine receptor subunit alpha-4 and beta-2 (α4β2 nicotinic receptor)

The neuronal acetylcholine receptor subunit alpha-4 and beta-2 (α4β2 nicotinic receptor) is a pentameric ligand-gated ion channel primarily expressed in the brain, formed by combinations of α4 (CHRNA4) and β2 (CHRNB2) subunits in stoichiometries such as (α4)3(β2)2 or (α4)2(β2)3. It functions by binding acetylcholine or nicotine, undergoing conformational changes that open a cation-selective pore permeable to Na+, K+, and Ca2+, resulting in post- and presynaptic excitation critical for learning, attention, and signal transduction. This receptor represents over 80% of high-affinity nicotine binding sites in the mammalian brain and mediates nicotine's addictive effects through its nanomolar affinity. Dysfunctions include CHRNA4 or CHRNB2 mutations causing epilepsy, while reduced expression contributes to cognitive deficits in Alzheimer's disease; certain mutations like CHRNA4 Ser248Phe also link to shorter stature and obesity predisposition. Drugs like nicotine act as agonists enhancing attention but pose addiction risks, while antagonists such as α-conotoxins or DHβE inhibit via the subunit interface binding pocket; structural studies confirm distinct assembly and trafficking determinants essential for cell surface expression. Therapeutic targeting focuses on neurological disorders, balancing efficacy in cognition against safety concerns like dependence and hormonal effects.

Other names

alpha-4 beta-2 nicotinic receptorα4β2 receptorCHRNA4/CHRNB2 nicotinic receptor

Agonist activation leading to increased Na+ and K+ permeability and cation channel opening, Antagonist competitive inhibition at ligand-binding pocket