title: RNA editing of the human serotonin 5-HT(2C) receptor delays agonist-stimulated calcium release.
abstract: RNA encoding the human 5-HT(2C) receptor undergoes adenosine-to-inosine RNA editing events at five positions in the putative second intracellular loop, with a corresponding reduction in receptor/G-protein coupling. Agonist-stimulated calcium release was examined in NIH-3T3 fibroblasts stably expressing the nonedited human INI (hINI) or the edited hVSV or hVGV variants. We hypothesized that different receptor isoforms would show altered dynamics of agonist-induced calcium release. The three isoforms showed a rightward shift in agonist concentration-response curves for eliciting calcium release (EC(50) values: hINI, 2.2 nM; hVSV, 15 nM; hVGV, 49 nM). Additionally, the hVGV receptor showed a blunted and delayed [Ca(2+)](i) peak compared with the hINI or hVSV receptor isoforms. These distinctions in agonist-induced [Ca(2+)](i) release imply that edited 5-HT(2C) receptors may produce distinct physiological responses within the central nervous system.
authors.affiliation: Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6600, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Price
authors.forename: E
authors.initials: E
authors.lastname: Sanders-Bush
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D017393:RNA Editing; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection
chemical_list: D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; D002118:Calcium