LABELING OF HIGH (D-2 RECEPTOR) AND LOW AFFINITY SITES BY [H-3]-LABELED DOMPERIDONE IN HOMOGENATES OF THE CORPUS STRIATUM OF THE RAT

Abstract

The binding of [3H]domperidone, a dopamine antagonist, to rat striatal membranes has been examined in vitro. Studies of the kinetics of [3H]domperidone binding and the saturation of binding sites at equilibrium revealed two specific binding sites for [3H]domperidone with apparent Kd values of 0.1 and > 2 nM, and maximal numbers of binding sites of 2 and 40 pmol/g wet wt. for the high and low affinity sites, respectively. The pharmacological properties of the high affinity site, determined in displacement studies using various dopamine agonists and selective dopamine antagonists, strongly suggested that this site labelled by [3H]domperidone is a dopamine receptor of the D-2 type. © 1982.