Dopamine and renal sodium transport

Dopamine (DA) is synthesized in renal proximal tubule (PT) cells and DA receptors have been located on PT membranes. DA inhibits transport of sodium across PT cells. The purpose of this study was to determine: (1) if DA-1 and/or DA-2 receptors are present in brush border membranes (BBM) and/or basolateral membranes (BLM), (2) if DA-1 and/or DA-2 receptors stimulate adenylate cyclase (AC) or phospholipase-C (PL-C) activity in either of these membrane types, and (3) if DA-1 and/or DA-2 agonists effect amiloride sensitive 22Na+ uptake into BBM vesicles. DA-1 and DA-2 receptors were measured in both BBM and BLM using radioligand binding techniques. The specific binding of [3H]SCH23390 and [125I]SCH23982 were found to consist of a high affinity saturable site and a non-saturable component