Neuronal nicotinic acetylcholine receptor alpha-3 beta-4 subtype (α3β4 nAChR) (α3β4 nAChR)

The neuronal nicotinic acetylcholine receptor alpha-3 beta-4 (α3β4) subtype is a pentameric ligand-gated ion channel primarily located in the autonomic ganglia, adrenal medulla, and specific brain regions such as the medial habenula and interpeduncular nucleus (UniProt P32297, P30926). It functions as a mediator of fast excitatory neurotransmission in the peripheral nervous system and plays a significant role in the regulation of the cholinergic-habenulo-interpeduncular pathway, which is involved in nicotine withdrawal and drug-seeking behavior (PubMed: 21515783). Genetic polymorphisms within the CHRNA5-A3-B4 gene cluster are highly correlated with nicotine dependence, smoking intensity, and the risk of developing lung cancer (PubMed: 18385676). Therapeutic targeting of the α3β4 receptor involves the use of agonists, partial agonists, and antagonists to modulate autonomic output and reward signaling. For instance, compounds like 18-methoxycoronaridine (18-MC) have been studied for their potential to treat addiction by antagonizing these receptors (PubMed: 15504544). However, drug development faces challenges due to the receptor's widespread expression in the autonomic nervous system, which can lead to side effects such as cardiovascular instability or gastrointestinal issues if selectivity is not achieved.

Other names

CHRNA3/CHRNB4 receptorAlpha-3 beta-4 nicotinic receptorGanglionic nicotinic acetylcholine receptorα3β4 nicotinic acetylcholine receptor

Agonists and partial agonists bind to the extracellular orthosteric site at the interface of alpha and beta subunits, triggering a conformational change that opens a cation-selective pore, leading to cell depolarization (PubMed: 17008354). Antagonists bind to the same site or act as non-competitive channel blockers to prevent ion flow, thereby inhibiting the physiological response to acetylcholine (PubMed: 15504544).