title: Nicotine enhances the locomotor stimulating but not the conditioned rewarding effect of ethanol in DBA/2J mice.
abstract: BACKGROUND
  One hypothesis to explain the high rate of nicotine and alcohol (ethanol [EtOH]) co-abuse is that these drugs have enhanced rewarding effects when taken together. The goal of this work was to use the conditioned place preference (CPP) procedure to determine whether nicotine would enhance the development of EtOH-induced CPP.
  
  
  METHODS
  The conditioned rewarding effects of nicotine (1 or 2 mg/kg of nicotine tartrate), EtOH (1 g/kg), and nicotine plus EtOH in combination were assessed using a well-established CPP procedure chosen specifically for examining alterations in the development of EtOH-induced CPP by nicotine. In addition, the reference dose procedure was used to directly compare the conditioned rewarding effect of EtOH versus nicotine plus EtOH. DBA/2J mice were used because they are an inbred strain that has repeatedly been shown to develop CPP to EtOH.
  
  
  RESULTS
  Neither dose of nicotine alone produced CPP, whereas EtOH did, using the standard EtOH CPP procedure. The magnitude of EtOH-induced CPP was not affected by co-administration of 1 mg/kg nicotine, but 2 mg/kg nicotine interfered with the development of EtOH-induced CPP. Using the reference dose procedure, there was no significant preference or aversion for either nicotine + EtOH dose combination versus EtOH alone. However, combined nicotine and EtOH had a larger effect on locomotor activity, during the conditioning trials, compared to their additive effect when given alone, consistent with previous data.
  
  
  CONCLUSIONS
  These data do not support the hypothesis that nicotine enhances the conditioned rewarding effect of EtOH. This finding differs from the combined locomotor stimulant effects of nicotine and EtOH that were observed in this study and in our previously published work, and suggests that combined stimulant effects of nicotine and EtOH do not predict enhanced reward.
authors.affiliation: Department of Behavioral Neuroscience and Portland Alcohol Research Center, Oregon Health & Science University, Portland, Oregon.
authors.forename: Noah R
authors.initials: NR
authors.lastname: Gubner
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Cunningham
authors.forename: Tamara J
authors.initials: TJ
authors.lastname: Phillips
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects*; D004357:Drug Synergism; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D012201:Reward
chemical_list: D000431:Ethanol; D009538:Nicotine
keywords: Alcohol; Conditioned Place Preference; Locomotor Activity; Reward