Dopamine Receptor

Dopamine receptors are also known to influence the immune system as well as cardiovascular, renal and gastrointestinal functions. As members of the GPCR superfamily, dopamine receptors have a canonical seven-transmembrane structure and can signal through both G protein-dependent and -independent mechanisms. Based on coupling to either Gαs,olf proteins or G i/o proteins to stimulate or inhibit the production of the second messenger cAMP, respectively, dopamine receptors are classified as D1-class receptors (D1 and D5) or D2-class receptors (D2, D3 and D4. Five subtypes of dopamine receptors (encoded in humans by genes DRD1, DRD2, DRD3, DRD4 and DRD5, respectively) are known to mediate essentially all of the physiological functions of dopamine. 
These functions include, but are not limited to, the following: voluntary movement, reward, sleep regulation, feeding, affect, attention, cognitive function, olfaction, vision, hormonal regulation, sympathetic regulation and penile erection. Modulation of cAMP synthesis by dopamine receptors results in the regulation of PKA and potentially of other exchange proteins activated by cAMP. When phosphorylated on Thr34 by PKA, DARPP-32 is a negative regulator of protein phosphatase 1 (PP1). In contrast, phosphorylation of DARPP-32 on Thr75 by cyclin-dependent kinase 5 (CDK5), in response to sustained D1 receptor activation, results in PKA inhibition. The roles of PKA and DARPP-32 in dopamine receptor signalling are well characterized, and strong evidence supports their contribution to the physiological functions of dopamine receptors.


1.Beaulieu JM,et al. Br J Pharmacol. 2015 Jan;172(1):1-23.