ALTERATION OF DOPAMINE RECEPTOR BINDING CHARACTERISTICS IN RAT LUNGS: RESPONSE TO RECEPTOR ACTIVATION WITH FENOLDOPAM ♦ 334

Abstract

We have previously demonstrated that the DA1 agonist, fenoldopam(fen) produces vasodilation in the preconstricted pulmonary vascular bed of the isolated perfused lung of the rat. We concluded that activation of vascular dopamine receptors were responsible for the results. However, we were unable to confirm these functional aspects of DA1 receptor activity with anatomical correlation with radio-ligand binding studies in the rat lung. Our initial experiments demonstrated low (0-3%) specific binding of a radiolabeled dopamine receptor antagonist, 3H-SCH 23390, on the adult rat lung.