title: Dopamine receptor binding sites in the rat superior colliculus.
abstract: Following intravenous administration of [3H]spiperone or [3H]N,n-propylnorapomorphine (NPA) to rats, radioactivity derived from the ligands accumulated in the striatum and superior colliculus when compared with cerebellar levels. The accumulation of [3H]spiperone in both areas was prevented by intraperitoneal administration of (+)-butaclamol, haloperidol and sulpiride but not by (-)-butaclamol, cinanserin, propranolol or prazosin. The accumulation of [3H]NPA was prevented by administration of (+)-butaclamol, haloperidol and apomorphine but not by (-)-butaclamol. In in-vitro experiments, membrane preparations from the superior colliculus showed a small number of specific binding sites for both [3H]spiperone and [3H]NPA. The dissociation constant (KD) for [3H]NPA was not different from that for striatal preparations but that for [3H]spiperone was 10-fold higher. We conclude that dopamine receptors may be present within the superior colliculus.
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives / Q000378:metabolism; D066298:In Vitro Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000032:analysis*; D013134:Spiperone / Q000378:metabolism; D013477:Superior Colliculi / Q000378:metabolism*
chemical_list: D011954:Receptors, Dopamine; D013134:Spiperone; C009074:N-n-propylnorapomorphine; D001058:Apomorphine