title: High impulsivity predicting vulnerability to cocaine addiction in rats: some relationship with novelty preference but not novelty reactivity, anxiety or stress.
abstract: BACKGROUND
  Impulsivity is a vulnerability marker for drug addiction in which other behavioural traits such as anxiety and novelty seeking ('sensation seeking') are also widely present. However, inter-relationships between impulsivity, novelty seeking and anxiety traits are poorly understood.
  
  
  OBJECTIVE
  The objective of this paper was to investigate the contribution of novelty seeking and anxiety traits to the expression of behavioural impulsivity in rats.
  
  
  METHODS
  Rats were screened on the five-choice serial reaction time task (5-CSRTT) for spontaneously high impulsivity (SHI) and low impulsivity (SLI) and subsequently tested for novelty reactivity and preference, assessed by open-field locomotor activity (OF), novelty place preference (NPP), and novel object recognition (OR). Anxiety was assessed on the elevated plus maze (EPM) both prior to and following the administration of the anxiolytic drug diazepam, and by blood corticosterone levels following forced novelty exposure. Finally, the effects of diazepam on impulsivity and visual attention were assessed in SHI and SLI rats.
  
  
  RESULTS
  SHI rats were significantly faster to enter an open arm on the EPM and exhibited preference for novelty in the OR and NPP tests, unlike SLI rats. However, there was no dimensional relationship between impulsivity and either novelty-seeking behaviour, anxiety levels, OF activity or novelty-induced changes in blood corticosterone levels. By contrast, diazepam (0.3-3 mg/kg), whilst not significantly increasing or decreasing impulsivity in SHI and SLI rats, did reduce the contrast in impulsivity between these two groups of animals.
  
  
  CONCLUSIONS
  This investigation indicates that behavioural impulsivity in rats on the 5-CSRTT, which predicts vulnerability for cocaine addiction, is distinct from anxiety, novelty reactivity and novelty-induced stress responses, and thus has relevance for the aetiology of drug addiction.
authors.affiliation: Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Molander
authors.forename: Adam
authors.initials: A
authors.lastname: Mar
authors.forename: Agnes
authors.initials: A
authors.lastname: Norbury
authors.forename: Sarah
authors.initials: S
authors.lastname: Steventon
authors.forename: Margarita
authors.initials: M
authors.lastname: Moreno
authors.forename: Daniele
authors.initials: D
authors.lastname: Caprioli
authors.forename: David E H
authors.initials: DE
authors.lastname: Theobald
authors.forename: David
authors.initials: D
authors.lastname: Belin
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Everitt
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Robbins
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Dalley
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001007:Anxiety / Q000097:blood / Q000517:prevention & control / Q000523:psychology*; D019970:Cocaine-Related Disorders / Q000097:blood / Q000517:prevention & control / Q000523:psychology*; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology; D003345:Corticosterone / Q000097:blood; D003975:Diazepam / Q000008:administration & dosage / Q000627:therapeutic use; D005106:Exploratory Behavior / Q000187:drug effects; D007175:Impulsive Behavior / Q000097:blood / Q000517:prevention & control / Q000523:psychology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D011237:Predictive Value of Tests; D051381:Rats; D011919:Rats, Inbred Strains; D013315:Stress, Psychological / Q000097:blood / Q000517:prevention & control / Q000523:psychology*
chemical_list: D014151:Anti-Anxiety Agents; D003975:Diazepam; D003345:Corticosterone