title: Functional relevance of serotonin 2C receptor mRNA editing in antidepressant- and anxiety-like behaviors.
abstract: Serotonin 2C receptors (5-HT(2C)R) have been shown to undergo post-transcriptional RNA editing. This modification affects the affinity, coupling and constitutive activity of the receptor. In vivo, manipulations such as stress or antidepressant administration dramatically modify the pattern of 5-HT(2C)R mRNA editing, suggesting that this phenomenon might be involved in the pathophysiology of stress-related disorders. Indeed, alterations of 5-HT(2C)R mRNA editing have been observed in depressed patients. Thus, the recent development of mice expressing either the non-edited (5-HT(2C)R-INI) or the fully-edited form of 5-HT(2C)R (5-HT(2C)R-VGV) provides a novel opportunity to investigate the relevance of this phenomenon in the context of stress-related disorders. We observed that both 5-HT(2C)R-INI and 5-HT(2C)R-VGV mice exhibit exaggerated anxiety-like behaviors in the elevated-plus maze paradigm. This phenotype was observed when the INI or VGV mutations were present in mice on a BALB/c background, as well as non-significant trends in the same direction in mice on a C57BL/6J background. In animal models of antidepressant-like activity, the absence of editing of 5-HT(2C)R mRNA (5-HT(2C)R-INI) induced an increase in the time spent immobile in the forced-swim test (FST) and tail suspension test (TST). Complete editing of 5-HT(2C) receptor mRNA (5-HT(2C)R-VGV) induced antidepressant-like behavior in the FST and TST, as reflected by a significant decrease in time spent immobile. These phenotypes were unrelated to alterations in locomotor activity in both 5-HT(2C)R-INI and 5-HT(2C)R-VGV. In the TST, these phenotypes were accompanied by a decrease and an increase in response to desipramine in 5-HT(2C)R-INI and 5-HT(2C)R-VGV, respectively. These data constitute the first in vivo demonstration of a role for 5-HT(2C)R mRNA editing in anxiety- and depression-related behaviors.
authors.affiliation: Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
authors.forename: Cedric
authors.initials: C
authors.lastname: Mombereau
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kawahara
authors.forename: Brigitta B
authors.initials: BB
authors.lastname: Gundersen
authors.forename: Kazuko
authors.initials: K
authors.lastname: Nishikura
authors.forename: Julie A
authors.initials: JA
authors.lastname: Blendy
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000235:genetics*; D001522:Behavior, Animal / Q000502:physiology*; D003863:Depression / Q000235:genetics*; D005260:Female; D019417:Hindlimb Suspension; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000235:genetics; D017393:RNA Editing / Q000235:genetics*; D044405:Receptor, Serotonin, 5-HT2C / Q000235:genetics* / Q000378:metabolism; D013550:Swimming; D013623:Tail
chemical_list: D044405:Receptor, Serotonin, 5-HT2C