title: The binding of [3H]N-(chloroethyl)-norapomorphine to rat striatal membranes.
abstract: N-(chloroethyl)-norapomorphine (NCA) irreversibly inhibits striatal dopamine function, the binding of dopamine agonist ligands and dopamine-stimulated adenylate cyclase. A selective interaction of [3H]NCA with dopamine receptor sites would be of use in the characterisation and isolation of brain dopamine receptors. In this study the binding of [3H]NCA to homogenates of rat striatum was investigated. Binding of [3H]NCA to striatal preparations was saturable and irreversible and prevented with high affinity by dopamine agonist drugs with a catechol moiety. However, binding was not prevented in a stereoselective manner by the isomers of butaclamol, flupenthixol or sultopride. Nor was [3H]NCA binding specific to brain areas containing dopamine receptors. We conclude that [3H]NCA binding is not selective for dopamine receptors, although NCA inhibited both [3H]N,n-propylnorapomorphine (NPA) and [3H]spiperone binding in a non-competitive manner.
mesh_terms: D000077582:Amisulpride; D000818:Animals; D001060:Aporphines / Q000378:metabolism*; D001667:Binding, Competitive; D002069:Butaclamol / Q000494:pharmacology; D003342:Corpus Striatum / Q000378:metabolism*; D018492:Dopamine Antagonists; D005260:Female; D005475:Flupenthixol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism; D013237:Stereoisomerism; D013469:Sulpiride / Q000031:analogs & derivatives / Q000494:pharmacology; D014316:Tritium
chemical_list: D001060:Aporphines; D018492:Dopamine Antagonists; D011954:Receptors, Dopamine; D014316:Tritium; D013134:Spiperone; C025935:chloroethylnorapomorphine; D013469:Sulpiride; D000077582:Amisulpride; D002069:Butaclamol; D005475:Flupenthixol