title: Evaluation of cage leaving behaviour in rats as a free choice paradigm.
abstract: BACKGROUND
  The free exploratory paradigm is regarded as a reliable test for trait anxiety in mice but it may also be useful in rats. Previously, we showed that rat strains differ in their free exploration of novel areas, i.e. the surroundings of their familiar home cage when the lid was removed.
  
  
  OBJECTIVE
  Therefore, the purpose of the present study was to further examine strain, sex, and age differences in animals from different breeders in combination with pharmacological treatment designed to modify anxiety.
  
  
  METHODS
  In the present study free exploratory behaviour test was evaluated in Sprague Dawley and Wistar rats from different breeders. We assessed seasonal variation, habituation to the test, and the impact of gender and age on exploration. Furthermore, we monitored exploration following intraperitoneal diazepam, 8-OH-DPAT and caffeine administration. Parameters measured were latency to start exploring the outside of the cage, the percentage of rats that explored the outside, as well as the number of visits.
  
  
  RESULTS
  There was no seasonal variability in free exploratory behaviour. However, strains and sexes differed in the test results, though age-related differences had less impact. Diazepam (2mg/kg) and 8-OH-DPAT (30, 100 and 300μg/kg) decreased neophobia while caffeine (50mg/kg) increased the latency to explore the outside the next day.
  
  
  CONCLUSIONS
  The free exploratory behaviour test can be used as a simple and complementary test to study trait anxiety-related behaviour in rats.
authors: Institute of Pharmacology and Toxicology, School of Veterinary Medicine, Freie, Universität Berlin, Koserstr. 20, 14195 Berlin, Germany.
authors: B
authors: B
authors: Bert
authors: Institute of Pharmacology and Toxicology, School of Veterinary Medicine, Freie, Universität Berlin, Koserstr. 20, 14195 Berlin, Germany.
authors: N
authors: N
authors: Schmidt
authors: University of Nottingham, School of Veterinary Medicine and Science, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, UK.
authors: J P
authors: JP
authors: Voigt
authors: Institute of Pharmacology and Toxicology, School of Veterinary Medicine, Freie, Universität Berlin, Koserstr. 20, 14195 Berlin, Germany.
authors: H
authors: H
authors: Fink
authors: Department of Neurology, Center for Stroke Research, Charité University Medicine, 10098 Berlin, Germany. Electronic address: andre.rex@charite.de.
authors: A
authors: A
authors: Rex
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000008:administration & dosage / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D001007:Anxiety / Q000188:drug therapy / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology; D002755:Choice Behavior / Q000187:drug effects / Q000502:physiology*; D003975:Diazepam / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012621:Seasons; D012737:Sex Factors; D013045:Species Specificity
chemical_list: D002110:Caffeine; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D003975:Diazepam
keywords: Anxiolytic drugs; Free exploratory behaviour; Gender; Rat; Strain differences; Trait anxiety