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 a pentaheteromeric complex with HTR3A. Not functional as a homomeric complex. Presumably retained within the endoplasmic reticulum unless complexed with HTR3A. Expressed in many tissues including adult brain, colon, intestine, lung, muscle and stomach as well as fetal colon and kidney. Belongs to the ligand-gated ion channel (TC 1.A.9) family. 5-hydroxytryptamine receptor (TC 1.A.9.2) subfamily. HTR3C sub-subfamily.