Regulation of blood pressure by dopamine receptors

Dopamine is an important regulator of blood pressure. Its actions on renal hemodynamics, epithelial transport and humoral agents such as aldosterone, catecholamines, endothelin, prolactin, pro-opiomelanocortin, renin and vasopressin place it in central homeostatic position for regulation of extracellular fluid volume and blood pressure. Dopamine also modulates fluid and sodium intake via actions in the central nervous system and gastrointestinal tract, and by regulation of cardiovascular centers that control the functions of the heart, arteries and veins. Abnormalities in dopamine production and receptor function accompany a high percentage of human essential hypertension and several forms of rodent genetic hypertension. Some dopamine receptor genes and their regulators are in loci linked to hypertension in humans and in rodents. Furthermore, single nucleotide polymorphisms (SNPs) of genes that regulate dopamine receptors, alone or via the interaction with SNPs of genes that regulate the renin-angiotensin system, are associated with human essential hypertension. Each of the five dopamine receptor subtypes (D1, D2, D3, D4 and D5) participates in the regulation of blood pressure by mechanisms specific for the subtype. Some receptors (D2 and D5) influence the central and/or peripheral nervous system; others influence epithelial transport and regulate the secretion and receptors of several humoral agents (e.g., the D1, D3 and D4 receptors interact with the renin-angiotensin system). Modifications of the usual actions of the receptor can produce blood pressure changes. In addition, abnormal functioning of these dopamine receptor subtypes impairs their antioxidant function.