HTR3A

The protein encoded by HTR3A is the 5-hydroxytryptamine receptor 3A subunit (5-HT3A), a key component of the 5-HT3 receptor—a ligand-gated ion channel in the Cys-loop superfamily. It forms homomeric or heteromeric channels with HTR3B subunits; upon 5-HT binding, the channel opens to permit cation (Na+, K+) influx, driving rapid neuronal depolarization in central and peripheral nervous systems.
Involved in 5-HT signaling, HTR3A regulates gastrointestinal motility, emetic reflex, and nociception. Dysregulation links to chemotherapy-induced nausea/vomiting (CINV), irritable bowel syndrome (IBS), anxiety, and depression. Clinically, 5-HT3 antagonists like ondansetron treat CINV, while novel HTR3A-targeted modulators are under development for IBS and psychiatric disorders.