PHARMACOLOGICAL CHARACTERIZATION AND AUTORADIOGRAPHIC LOCALIZATION OFDOPAMINE-D(1) RECEPTORS IN THE HUMAN UMBILICAL ARTERY

Combined in vitro radioreceptor binding and autoradiographic technique s with [H-3]SCH 23390 as a ligand were used to analyze the pharmacolog ical profile and anatomical localization of dopamine D1 receptor sites in sections of human umbilical artery. The ligand was bound to sectio ns of the artery in a manner consistent with the labelling of D1 recep tors. These receptors, which show a fetal-to-maternal gradient with th e highest concentration near the placenta, are located within the smoo th muscle layer of the umbilical artery. The above findings suggest th at endogenous dopamine may be involved in the control of the tone of t he umbilical artery through the interaction with D1 receptors.