CHRNB3

CHRNB3 is a gene that encodes a subunit of the neuronal nicotinic acetylcholine receptor (nAChR). Specifically, it encodes the beta 3 subunit (β3). nAChRs are ligand-gated ion channels that mediate fast synaptic transmission in the nervous system and are activated by acetylcholine, as well as nicotine and other related compounds.

The β3 subunit, along with other subunits such as alpha 5 (α5) and alpha 3 (α3), assembles to form functional heteromeric nAChRs. The precise subunit composition of these receptors determines their pharmacological properties, including ligand binding affinity, channel kinetics, and desensitization characteristics. Receptors containing the β3 subunit are expressed in various brain regions, including the ventral tegmental area (VTA) and the habenula, and play roles in reward, addiction, and mood regulation.

Genetic variations in the CHRNB3 gene have been associated with a range of phenotypes, including nicotine dependence, alcohol dependence, opioid dependence, and other substance use disorders. Furthermore, variations have been linked to individual differences in response to smoking cessation therapies. These associations suggest that the β3 subunit plays a crucial role in the neurobiological mechanisms underlying addiction and reward.

Research into the CHRNB3 gene and its associated receptor subunit is ongoing to further elucidate its functional role in the brain and its contribution to neurological and psychiatric disorders.