Serotonin 5-hydroxytryptamine receptor subtype 3 (5-HT3 receptor)

The **Serotonin 5-hydroxytryptamine receptor subtype 3** (**5‑HT₃ receptor**) is a member of the Cys-loop superfamily of ligand-gated ion channels. Unlike other serotonin receptors that are G protein-coupled, the 5‑HT₃ receptor forms a pentameric structure that creates an ion channel permeable to cations such as Na⁺ and K⁺. It is widely expressed in both central and peripheral nervous systems where it mediates fast excitatory neurotransmission. Activation by serotonin leads to rapid depolarization of neurons involved in processes such as emesis, anxiety modulation, pain perception, and gastrointestinal motility. Clinically important antagonists targeting this receptor are used primarily to prevent or treat chemotherapy-induced nausea and vomiting as well as irritable bowel syndrome with diarrhea predominance. The main safety concerns relate to gastrointestinal side effects like constipation or rare but serious complications such as ischemic colitis.[1][2][4]

Other names

5-HT3 receptorSerotonin receptor 3HTR3 (gene family)

Antagonists block serotonin binding, preventing activation of the ion channel and subsequent neuronal excitation, thus reducing nausea/vomiting or modulating gut motility/neurological effects.[1][2][7]