The dopamine receptor D4 is a G protein-coupled receptor encoded by the DRD4 gene. As with other dopamine receptor subtypes, the D4 receptor is activated by the neurotransmitter dopamine. It is linked to many neurological and psychiatric conditions including schizophrenia and bipolar disorder, addictive behaviors,Parkinsons disease, and eating disorders such as anorexia nervosa.
It is also a target for drugs which treat schizophrenia and Parkinson disease. The D4 receptor is considered to be D2-like in which the activated receptor inhibits the enzyme adenylate cyclase, thereby reducing the intracellular concentration of the second messenger cyclic AMP.
The human protein is coded by the DRD4 on chromosome 11 located in 11p15.5.
There are slight variations (mutations/polymorphisms) in the human gene: