5-hydroxytryptamine receptor 3D (HTR3D)

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. .