Specific [3H]piflutixol binding to CHAPS-solubilised rat striatal preparations involves dopamine D-2 but not D-1 binding sites.
[3H]Piflutixol binding to rat striatal membrane preparations identifies both D-1 and D-2 sites. We used [3H]piflutixol to characterise those binding sites present in 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)-solubilised rat striatal preparations. The specific binding of [3H]piflutixol, as defined using cis-flupenthixol, to CHAPS-solubilised rat striatal tissue was saturable and of high affinity. Specific [3H]piflutixol binding to the solubilised preparations was displaced stereoselectively by the isomers of butaclamol and to an equal extent by both cis-flupenthixol and (+/-)-sulpiride. A positive correlation was found between the capacity of a range of drugs to displace [3H]piflutixol binding and the displacement of [3H]spiperone to the same preparations. The Bmax of [3H]piflutixol binding was not different from that of [3H]spiperone binding to the same preparation. These studies suggest that, in contrast to specific binding of membrane preparations, the specific binding of [3H]piflutixol to CHAPS-solubilised preparations involves mainly D-2 sites. Specific [3H]piflutixol binding, in contrast to [3H]spiperone binding, showed only slow dissociation from soluble preparations. The binding of [3H]piflutixol to CHAPS-solubilised preparations was retained during passage through a gel filtration column. This prelabelling of solubilised striatal preparations using [3H]piflutixol may aid in the purification of CHAPS-solubilised rat striatal D-2 sites.
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002793:Cholic Acids; D002850:Chromatography, Gel; D003342:Corpus Striatum / Q000378:metabolism*; D005475:Flupenthixol / Q000378:metabolism; D007536:Isomerism; D007700:Kinetics; D051381:Rats; D011954:Receptors, Dopamine / Q000378:metabolism*; D012995:Solubility; D013134:Spiperone / Q000378:metabolism; D013469:Sulpiride / Q000378:metabolism; D013892:Thioxanthenes / Q000378:metabolism*
D002793:Cholic Acids; D011954:Receptors, Dopamine; D013892:Thioxanthenes; D013134:Spiperone; D013469:Sulpiride; C015448:piflutixol; D005475:Flupenthixol; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate