Background：

This gene encodes one of the several different receptors for 5-hydroxytryptamine (serotonin) that belongs to the G-protein coupled receptor 1 family. Serotonin is a biogenic hormone that functions as a neurotransmitter， a hormone， and a mitogen. Serotonin receptors mediate many of the central and peripheral physiologic functions of serotonin， including regulation of cardiovascular functions and impulsive behavior. Population and family-based analyses of a minor allele (glutamine-to-stop substitution， designated Q20*) which blocks expression of this protein， and knockout studies in mice， suggest a role for this gene in impulsivity. However， other factors， such as elevated testosterone levels， may also be involved. Alternatively spliced transcript variants have been found for this gene.