HTR3B is one of the several different ligand-gated ion channel receptors for 5- hydroxytrptamine (serotonin), a biogenic hormone that functions as a hormone, a neurotransmitter, and a mitogen. It is a cation-specific, but otherwise relatively nonselective ion channel that, when activated, causes fast depolarizing responses in neurons. A functional channel may be composed of five identical 5-HT3A subunits (homopentameric) or a mixture of 5-HT3A and one of the other four 5-HT3B, 5-HT3C, 5- HT3D, or 5-HT3E subunits (heteropentameric). It appears that only the 5-HT3A subunits form functional homopentameric channels. All other subunit subtypes must heteropentamerize with 5-HT3A subunits to form functional channels.

The receptor is available in the following formats: stable over-expression cell line, membrane preparation, or purified receptor in HEK293 or CHO. Various tagged versions are available.