Characterization of a cloned rat serotonin 5-HT1A receptor expressed in the HeLa cell line

Yutaka Fujiwara, Hiroaki Tomita, Mitsuru Hikiji, Kenichi Kashihara, Saburo Otsuki, Tetsuo Ohnuki, Yasutaro Hamagishi, Toshikazu Oki, Ichiro Sora, William R. Roeske, Henry I. Yamamura

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15 Citations (Scopus)


We have previously isolated the rat serotonin (5-HT)1A receptor gene (G21Y2) and now report the expression and characterization of this receptor. The BamHl/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 μM) 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 μM. 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.

Original languageEnglish
Pages (from-to)949-958
Number of pages10
JournalLife Sciences
Issue number11
Publication statusPublished - 1993


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