Renal dopamine receptors: Mechanisms of action and developmental aspects

Dopamine is important for renal perfusion, natriuresis, and the control of blood pressure. Modulation of the activities of adenylyl cyclase, phospholipase C and protein kinases is involved in the signal transduction pathway of dopamine. Peripheral dopamine receptors are classified as the DA(1) and DA(2) subtypes on the basis of synaptic localization and their pharmacological profiles, In the kidney, DA(1) receptors are localized in the medial layer of the renal vasculature and along the nephron; DA(2) receptors are found in the glomerulus and the nerves surrounding renal blood vessels, While DA(1) receptor stimulation results in renal vasodilatation and natriuresis, DA(2) receptors may play a synergistic role in the DA(1) modulated natriuresis. There is increasing evidence that these effects of dopamine are attenuated in younger than in older animals. Future studies should be directed to identify the ontogenic differences in vascular and tubular dopamine receptors (density and affinity) and their coupling mechanisms, in order to evaluate the role of dopamine which is frequently used in the management of shock in newborns.