α5-containing neuronal nicotinic acetylcholine receptor complexes (α5* nAChR)

α5-containing neuronal nicotinic acetylcholine receptor (α5* nAChR) complexes are pentameric ligand-gated ion channels that incorporate the α5 accessory subunit, encoded by the CHRNA5 gene. Unlike other alpha subunits, α5 does not form functional receptors on its own or contribute directly to the primary acetylcholine binding site; instead, it acts as an accessory subunit that modulates the biophysical and pharmacological properties of the receptor complex. These complexes typically consist of an α4β2 or α3β4 backbone, such as the (α4β2)2α5 and (α3β4)2α5 stoichiometries. The inclusion of the α5 subunit significantly increases the receptor's calcium permeability and alters its sensitivity to nicotine and its desensitization kinetics. Biologically, α5* nAChRs are critical regulators of the brain's reward and aversion circuits, particularly in the ventral tegmental area and the medial habenula-interpeduncular nucleus pathway. Genetic variants in the CHRNA5 gene are strongly associated with an increased risk of nicotine dependence, heavy smoking, and lung cancer. Consequently, these receptors are major therapeutic targets for smoking cessation and are being explored for roles in treating cognitive disorders, schizophrenia, and chronic pain.

Other names

alpha5 nicotinic receptoralpha5-containing nAChRCHRNA5-containing nAChR(alpha4beta2)2alpha5 nAChR(alpha3beta4)2alpha5 nAChR

Agonism, Partial agonism, Antagonism, Positive allosteric modulation