title: Magnesium ions reveal nanomolar potency of dopamine at [3H]spiperone labelled D-2 receptors in rat corpus striatum.
abstract: Preparation and assay of rat striatal membranes in the presence of 10 mM magnesium ions resulted in an IC50 value constant for dopamine of 13 nM at D-2 dopamine receptors labelled by [3H]spiperone. Inclusion of 100 microM GTP under these conditions resulted in a 13 fold decrease in dopamine displacing potency. Displacing potencies for dopamine in the nanomolar range are associated with agonist-specific D-3 receptor binding and it is predicted that the component of D-2 binding with high agonist affinity may play a confounding role in many D-3 receptor studies.
authors.forename: D J
authors.initials: DJ
authors.lastname: De Vries
authors.forename: P M
authors.initials: PM
authors.lastname: Beart
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*; D017448:Receptors, Dopamine D2; D013134:Spiperone / Q000378:metabolism; D013268:Stimulation, Chemical
chemical_list: D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D013134:Spiperone; D006160:Guanosine Triphosphate; D008274:Magnesium; D004298:Dopamine