Dopamine Receptors

Dopamine receptors are rhodopsin-like seven-transmembrane receptors (also called G protein-coupled receptors) that mediate the central and peripheral actions of dopamine. Dopamine receptors are most abundant in pituitary and brain, particularly in the basal forebrain, and are also found in the retina and peripheral organs such as the kidney. Stimulation of dopamine receptors modulates excretion of sodium by the kidney, and both cell division and hormone synthesis and secretion in the pituitary. Brain dopamine receptors regulate movement and locomotion, motivation, and working memory. Five subtypes of mammalian dopamine receptors have been identified that are divided into D1-like (D1 and D5) or D2-like (D2, D3, and D4) groups. The D1-like receptors couple primarily to the Gα_s family of G proteins (Gα_s and Gα_olf), whereas the D2-like receptors couple primarily to the Gα_i/o family. Drugs that block D2 receptors are useful for the treatment of schizophrenia and other psychoses, while drugs that stimulate D1-like or D2-like receptors alleviate the motor symptoms that result from degeneration of dopamine-containing neurons in Parkinson's disease.