title: Characterization of a cloned rat serotonin 5-HT1A receptor expressed in the HeLa cell line.
abstract: We have previously isolated the rat serotonin (5-HT)1A receptor gene (G21Y2) and now report the expression and characterization of this receptor. The BamHI/Xbal fragment of this gene was cloned into Rc/RSV and stably transfected into HeLa cells by the calcium phosphate method. For determination of specific 5-HT1A receptor binding, [3H]8OH-DPAT was used as the radioligand and incubated with HeLa cell membranes. The cells expressed specific and saturable binding of [3H]8OH-DPAT with a Kd value of 0.3 nM and a Bmax value of 2 pmol/mg protein. GTP (50 microM) added to the incubation mixture increased the Kd value to 3 nM indicating that the expressed receptor is coupled to a G protein. The specific binding was inhibited by selective 5-HT1A partial agonists, such as buspirone, ipsapirone, gepirone, tandospirone, zalospirone and SUN8399 with Ki values of 1-30nM, whereas other neurotropic drugs except for spiperone (Ki = 46 nM) and nemonapride (Ki = 2.3 nM) were effective only at concentrations of more than 100 microM. The potencies of these compounds to inhibit [3H]8OH-DPAT from its specific binding sites were similar to their affinities determined in rat hippocampus binding studies. These data suggest that the expressed receptor is a 5-HT1A-type similar to 5-HT1A receptors in the rat hippocampus.
authors.affiliation: Department of Neuropsychiatry, Okayama University Medical School, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: H
authors.initials: H
authors.lastname: Tomita
authors.forename: M
authors.initials: M
authors.lastname: Hikiji
authors.forename: K
authors.initials: K
authors.lastname: Kashihara
authors.forename: S
authors.initials: S
authors.lastname: Otsuki
authors.forename: T
authors.initials: T
authors.lastname: Ohnuki
authors.forename: Y
authors.initials: Y
authors.lastname: Hamagishi
authors.forename: T
authors.initials: T
authors.lastname: Oki
authors.forename: I
authors.initials: I
authors.lastname: Sora
authors.forename: W R
authors.initials: WR
authors.lastname: Roeske
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000378:metabolism*; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001667:Binding, Competitive; D003001:Cloning, Molecular; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D051381:Rats; D011985:Receptors, Serotonin / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D017366:Serotonin Receptor Agonists / Q000378:metabolism / Q000494:pharmacology; D013134:Spiperone / Q000494:pharmacology; D014162:Transfection
chemical_list: D014150:Antipsychotic Agents; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; D013134:Spiperone; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D006160:Guanosine Triphosphate