Alpha-4 beta-4 neuronal nicotinic acetylcholine receptor (α4β4 nAChR)

The alpha-4 beta-4 neuronal nicotinic acetylcholine receptor (α4β4 nAChR) is a heteromeric ligand-gated ion channel composed of α4 (CHRNA4) and β4 (CHRNB4) subunits (UniProt: P43681, P30926). It belongs to the Cys-loop superfamily of receptors and is primarily involved in mediating fast synaptic transmission and modulating neurotransmitter release in the central and peripheral nervous systems (PubMed: 16825297). Although the α4β2 subtype is more abundant in the brain, α4β4 receptors exhibit distinct pharmacological properties, such as higher current amplitudes and slower desensitization rates when activated by agonists like nicotine or acetylcholine (PubMed: 16825297). This receptor subtype is a key target in the study of nicotine addiction, as it contributes to the rewarding and reinforcing effects of tobacco (NIH: PMC1995635). Furthermore, genetic polymorphisms in the CHRNB4 gene cluster are strongly associated with nicotine dependence and smoking-related diseases, making the α4β4 receptor a focus for developing smoking cessation aids and treatments for cognitive or neurodegenerative disorders (PubMed: 20881005).

Other names

CHRNA4/CHRNB4 receptoralpha4beta4 nicotinic receptornAChR alpha4beta4Neuronal acetylcholine receptor alpha-4/beta-4

The alpha-4 beta-4 neuronal nicotinic acetylcholine receptor functions as a pentameric ligand-gated ion channel that opens upon the binding of acetylcholine or exogenous agonists like nicotine (PubMed: 16825297). This opening allows the influx of cations, primarily sodium and calcium, leading to neuronal depolarization and the subsequent release of neurotransmitters such as dopamine and glutamate (PubMed: 16825297). Drugs can act as agonists, partial agonists, or antagonists at the orthosteric binding sites located at the interfaces between alpha and beta subunits, thereby modulating the excitability of the reward and aversion pathways in the brain (NIH: PMC1995635).