Anatomical distribution and function of dopamine receptors in the kidney.
Dopamine receptors of DA-1 and DA-2 subtypes are localized in various regions within the kidney including the renal vasculature (DA-1) as well as sympathetic nerve terminals innervating the renal blood vessels (DA-2). More recent studies using receptor-ligand binding and receptor autoradiography have shown that DA-1 receptors are localized at both the luminal and basolateral membranes at the level of the proximal tubules. Activation of these DA-1 receptors by dopamine and by selective DA-1 receptor agonists results in natriuresis and diuresis. The cellular signaling mechanisms responsible for this response appear to be DA-1 receptor-induced activation of adenylate cyclase and phospholipase C, which via the generation of various intracellular messenger systems cause inhibition of Na(+)-H+ antiport (luminal) and Na+, K(+)-ATPase (basolateral), respectively. Both of these events consequently inhibit sodium reabsorption leading to natriuresis and diuresis. It is also known that dopamine can be synthesized within proximal tubular cells from L-dopa, which is taken up from the tubular lumen, and this locally produced dopamine plays an important role in the regulation of sodium excretion particularly during increases in sodium intake. Furthermore, a defect in the renal dopaminergic mechanism may be one of the pathogenic factors in certain forms of hypertension. Finally, whereas DA-1 receptor agonists are shown to be of therapeutic benefit in the treatment of hypertension, heart failure, and acute renal failure, some selective DA-2 receptor agonists are effective antihypertensive agents.
Lokhandwala
M F
MF
Department of Pharmacology, University of Houston, TX 77204-5515.
Amenta
F
F
D000818:Animals; D015259:Dopamine Agents / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000378:metabolism; D007668:Kidney / Q000033:anatomy & histology* / Q000502:physiology; D011954:Receptors, Dopamine / Q000502:physiology*; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D015398:Signal Transduction; D012964:Sodium / Q000378:metabolism
D015259:Dopamine Agents; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012964:Sodium