Localisation and pharmacological characterisation of D-2 dopamine receptors in rat cerebral neocortex and cerebellum using [125I]iodosulpride.
Dopamine D-2 receptors were characterised in membranes from all areas of rat cerebral cortex and from cerebellum tested, by using [125I]iodosulpride, a highly selective ligand. The IC50 values of a large variety of dopaminergic and non-dopaminergic agents against [125I]iodosulpride binding in parietal cortex or cerebellum were highly correlated with their IC50 values against [125I]iodosulpride (or [3H]domperidone) binding in striatum. Moreover in the presence of a guanylnucleotide, 5'-guanylylimidodiphosphate (GppNHp), the dopamine inhibition curves of [125I]iodosulpride binding were shifted similarly to the right in the three regions. The density of D-2 receptors in cerebellum and in most areas of the cerebral cortex represented about 1% and 2%, respectively, of their density in striatum whereas the corresponding value in frontal cortex was 4%. Labelling on autoradiographic sections was localised to superficial (I-III) and deep layers (V) of the parietal cortex and to the molecular layer of the cerebellum.
D000818:Animals; D001345:Autoradiography; D002531:Cerebellum / Q000187:drug effects*; D002540:Cerebral Cortex / Q000187:drug effects*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D008297:Male; D008566:Membranes / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D017448:Receptors, Dopamine D2; D013469:Sulpiride / Q000031:analogs & derivatives* / Q000494:pharmacology
D007457:Iodine Radioisotopes; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; C045105:iodosulpride; D006165:Guanylyl Imidodiphosphate; D013469:Sulpiride