The product of this gene belongs to the ligand-gated ion channel receptor superfamily. This gene encodes subunit B of the type 3 receptor for 5-hydroxytryptamine (serotonin), a biogenic hormone that functions as a neurotransmitter, a hormone, and a mitogen. This receptor causes fast, depolarizing responses in neurons after activation. It is not functional as a homomeric complex, but a pentaheteromeric complex with subunit A (HTR3A) displays the full functional features of this receptor.