Neuronal acetylcholine receptor subunit alpha-9 (CHRNA9)

Neuronal acetylcholine receptor subunit alpha-9 (CHRNA9) is a subunit of the nicotinic acetylcholine receptor (nAChR) family, specifically contributing to pentameric, ligand-gated ion channels permeable to divalent cations, notably calcium. CHRNA9 assembles into homo- or heteromeric channels (often with CHRNA10), mediating cholinergic neurotransmission in the cochlea and playing a vital role in auditory processing by modulating hair cell membrane potential and synaptic transmission. It is expressed in cochlear hair cells, keratinocytes, pituitary, B-cells, and T-cells. Genetic variants and alternative splicing of CHRNA9 influence cell proliferation and carcinogenic transformation, particularly in bronchial epithelial and breast tissue, implicating CHRNA9 in cancer biology and tobacco addiction. Selective antagonists (e.g., conotoxin RgIA) demonstrate analgesic potential by blocking these channels. The receptor’s non-neuronal roles, channel selectivity, and pharmacological modulation present both therapeutic opportunities and safety challenges, including risks for hearing impairment and oncogenic transformation.

Other names

Cholinergic receptor nicotinic alpha 9 subunitCHRNA9NACHRA9NACHR alpha-9Nicotinic acetylcholine receptor subunit alpha-9Acetylcholine receptor, nicotinic, alpha 9 (neuronal)Cholinergic receptor, nicotinic, alpha polypeptide 9Neuronal acetylcholine receptor protein, alpha-9 subunitAcetylcholine receptor, neuronal nicotinic, alpha-9 subunitCholinergic receptor, nicotinic alpha 9Cholinergic receptor, nicotinic, alpha 9 (neuronal)HSA243342

Ligand binding (agonist/antagonist) alters channel permeability to divalent cations (e.g., calcium, potassium); Conotoxin RgIA: selective blockade of α9α10, produces analgesic effects via channel inhibition; Nicotine: blockade/antagonism of α9-containing nAChRs