Effect of neuropeptide-EI on the binding of [H-3]SCH 23390 to the dopamineD-1 receptor in rat striatal membranes

We have previously demonstrated that neuropeptide-EI, at high doses, stimul ates the production of cAMP, in caudate putamen, through the activation of adenylate cyclase coupled to specific D-1 receptors. The aim of the present work was to find evidences for a probable interaction between this neurope ptide and the dopamine D-1 receptor in the mammalian central nervous system . The present data show that neuropeptide-EI, at high concentrations, affec ted both the maximum binding and the apparent affinity of [n-methyl-H-3] (R )-(+)-8 chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol he rnimaleate to the dopamine D-1 receptor in a concentration-dependent manner .