5-Hydroxytryptamine Receptor 3B (HTR3B)

HTR3Bencodes 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 appears that the heteromeric combination of A and B subunits is necessary to provide the full functional features of this receptor, since either subunit alone results in receptors with very low conductance and response amplitude. The authors determined that HTR3B cannot assemble as a homomeric HTR3 receptor but that heteromeric HTR3A/HTR3B receptors display a large single-channel conductance (16 pS), low permeability to calcium ions, and a current-voltage relationship resembling that of characterized neuronal HTR3 channels.