title: Acute nicotine increases both impulsive choice and behavioural disinhibition in rats.
abstract: BACKGROUND
  Heavy smokers exhibit greater levels of impulsive choice and behavioural disinhibition than non-smokers. To date, however, the relationship between nicotine use and differing dimensions of impulsivity has not been systematically assessed.
  
  
  OBJECTIVE
  A series of studies was designed to assess the acute dose-response effects of nicotine and the nicotinic receptor antagonist mecamylamine alone, and in combination with nicotine, on impulsive choice and behavioural disinhibition in rats.
  
  
  METHODS
  Separate groups of rats were trained on a symmetrically reinforced go/no-go task to measure levels of disinhibition and a systematic delayed reward task to measure levels of impulsive choice. Once trained, all animals in each task were treated acutely with nicotine (0.125, 0.25, 0.5 and 1.0 mg/kg), mecamylamine (0.1, 0.3 and 1.0 mg/kg) and varying doses of mecamylamine (0.1, 0.3 and 1.0 mg/kg) prior to nicotine (0.5 mg/kg). An additional experiment assessed the effects of alterations in primary motivation (presatiation and fasting) on performance in both tasks.
  
  
  RESULTS
  Acute nicotine increased both impulsive choice and behavioural disinhibition, effects that were blocked by pre-treatment with mecamylamine. Mecamylamine when administered alone did not alter impulsive behaviour. The lack of effect of presatiation on performance measures suggests that the observed nicotine-induced impulsivity cannot be attributed to the anorectic activity of the compound.
  
  
  CONCLUSIONS
  Present findings support the hypothesis that heightened impulsivity in smokers may in part be a consequence of the direct acute effects of nicotine. As such, drug-induced changes in impulsivity may play a critical role in the transition to and maintenance of nicotine dependence.
authors.affiliation: Department of Psychology, Leeds Metropolitan University, D420 Civic Quarter, Calverley Street, Leeds, LS1 3HE, UK. z.kolokotroni@leedsmet.ac.uk
authors.forename: Katerina Zoe
authors.initials: KZ
authors.lastname: Kolokotroni
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Rodgers
authors.forename: Amanda A
authors.initials: AA
authors.lastname: Harrison
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002755:Choice Behavior / Q000187:drug effects*; D003216:Conditioning, Operant; D007175:Impulsive Behavior / Q000188:drug therapy*; D007266:Inhibition, Psychological; D007279:Injections, Subcutaneous; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011978:Receptors, Nicotinic / Q000378:metabolism; D012054:Reinforcement, Psychology
chemical_list: D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D008464:Mecamylamine; D009538:Nicotine