This is one of the several different receptors for 5-hydroxytryptamine (serotonin), a biogenic hormone that functions as a neurotransmitter, a hormone, and a mitogen. This receptor is a ligand-gated ion channel, which when activated causes fast, depolarizing responses. It is a cation-specific, but otherwise relatively nonselective, ion channel. Forms pentahomomeric complex as well as pentaheteromeric complex with HTR3B; homomeric complex is functional but exhibits low conductance with modified voltage dependence and antagonist affinity. Presumably retained within the endoplasmic reticulum unless complexed with HTR3A. Expressed in peripheral neurons, but not in neurons of the central nervous system. By nerve growth factor in PC12 cells. N-glycosylation is required for membrane localization. Belongs to the ligand-gated ion channel (TC 1.A.9) family. 5-hydroxytryptamine receptor (TC 1.A.9.2) subfamily. HTR3B sub-subfamily.