title: Assessing anxiety in C57BL/6J mice: a pharmacological characterization of the open-field and light/dark tests.
abstract: BACKGROUND
  In order to assess anxiety in mammals various tests and species are currently available. These current assays measure changes in anxiety-like behaviors. The open-field and the light/dark are anxiety tests based on the spontaneous behavior of the animals, with C57BL/6J mice being a frequently used strain in behavioral studies. However, the suitability of this strain as a choice in anxiety studies has been questioned. In this study, we performed two pharmacological characterizations of this strain in both the open-field and the light/dark tests.
  
  
  METHODS
  We examined the changes in the anxiety-like behaviors of C57BL/6J mice exposed to chlordiazepoxide (CDP), an anxiolytic drug, at doses of 5 and 10 mg/kg, picrotoxine (PTX), an anxiogenic drug, at doses of 0.5 and 1 mg/kg, and methylphenidate (MPH), a psychomotor stimulant drug, at doses of 5 and 10 mg/kg, in a first experiment. In a second experiment, we tested CDP at 2.5 mg/kg, PTX at 2 mg/kg and MPH at 2.5 mg/kg.
  
  
  RESULTS
  Results showed an absence of anxiolytic-like effects of CDP in open-field and light/dark tests. Light/dark test was more sensitive to the anxiogenic effects of PTX than the open-field test. Finally, a clear anxiogenic effect of MPH was observed in the two tests.
  
  
  CONCLUSIONS
  Although C57BL/6J mice could not be a sensitive model to study anxiolytic effects in pharmacological or behavioral interventions, it might be a suitable model to test anxiogenic effects. Further studies are necessary to corroborate these results.
authors.affiliation: CRAMC (Research Center for Behavior Assessment), Department of Psychology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain. Electronic address: luis.heredia@urv.cat.
authors.forename: Luis
authors.initials: L
authors.lastname: Heredia
authors.affiliation: CRAMC (Research Center for Behavior Assessment), Department of Psychology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain. Electronic address: margarita.torrente@urv.cat.
authors.forename: Margarita
authors.initials: M
authors.lastname: Torrente
authors.affiliation: CRAMC (Research Center for Behavior Assessment), Department of Psychology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain. Electronic address: mariateresa.colomina@urv.cat.
authors.forename: María T
authors.initials: MT
authors.lastname: Colomina
authors.affiliation: Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain. Electronic address: joseluis.domingo@urv.cat.
authors.forename: José L
authors.initials: JL
authors.lastname: Domingo
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy* / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D002707:Chlordiazepoxide / Q000008:administration & dosage / Q000494:pharmacology; D003624:Darkness; D004305:Dose-Response Relationship, Drug; D008027:Light; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010852:Picrotoxin / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D014151:Anti-Anxiety Agents; D002707:Chlordiazepoxide; D008774:Methylphenidate; D010852:Picrotoxin
keywords: C57BL/6J mice; Chlordiazepoxide; Light/dark test; Methods; Methylphenidate; Open-field test; Picrotoxine