Serotonin receptor 5-HT3A (5-HT3A)

The Serotonin receptor 5-HT3A is a ligand-gated ion channel, forming part of the Cys-loop receptor superfamily, distinct from other serotonin receptor subtypes which are G-protein-coupled. It is composed of five subunits (homopentameric or heteropentameric), but only channels containing 5-HT3A subunits can form functional homopentameric assemblies. Upon activation by serotonin binding at its extracellular domain, the receptor opens to permit cation influx, leading to rapid neuronal depolarization and excitation, particularly in the central and peripheral nervous systems. 5-HT3A receptors play a key role in nausea and vomiting pathways, pain perception, anxiety, and gut motility. It is a well-established therapeutic target, with antagonists used primarily to treat chemotherapy- and radiotherapy-induced nausea and vomiting, and studied for roles in irritable bowel syndrome, neuropsychiatric, and pain disorders. Safety concerns primarily relate to cardiac electrical effects and individual genetic variance impacting drug efficacy.

Other names

5-HT3A5-hydroxytryptamine receptor 3AHTR3ASerotonin 5-HT3A receptor

Antagonists inhibit the receptor to prevent serotonin-induced activation of the ion channel, thereby blocking neuronal excitation (most clinical drugs are antagonists). Agonists activate the receptor, leading to cation influx and depolarization of neurons.