title: The effect of previous exposure to nicotine on nicotine place preference.
abstract: BACKGROUND
  Prior exposure to drugs of abuse may increase or decrease the reinforcing effects of the drug in later consumptions. Based on the initial locomotor activity (LA) response to an acute drug administration or to novelty in an open-field arena, animals can be classified as low or high LA responders (LR or HR). Few studies have used this classification with nicotine, and the results are controversial. Some authors suggested that nicotine can induce conditioned-place preference (CPP) following prior nicotine exposure, whereas others suggested that previous nicotine exposure extinguishes nicotine-CPP.
  
  
  OBJECTIVE
  To explore if the administration of nicotine in a novel environment without explicit behavioral consequences to classify animals in low and high nicotine responders (LNR and HNR) could affect the establishment of nicotine CPP in male Sprague-Dawley rats.
  
  
  RESULTS
  Prior exposure to a single dose of nicotine (0.4 mg/kg, subcutaneously) induced CPP in LNR rats after 14 days of conditioning (seven-trial) but not after two or eight conditioning days. In contrast, HNR rats did not show CPP under any condition. In addition, our results indicated that previous exposure to nicotine decreased its rewarding effects in eight conditioning days CPP (four-trial), which can be regularly established without prior exposure to nicotine.
  
  
  CONCLUSIONS
  The results suggested that response to a single exposure to nicotine predicts the acquisition of nicotine preference in a 14-day conditioning protocol only for LNR rats. Thus, our findings demonstrated the relevance of using LNR and HNR classification when the individual susceptibility to nicotine preference is studied.
authors.affiliation: Department of Physiology and Institute of Cell Biology, School of Medicine, University of Buenos Aires, Paraguay 2155 7th floor, C1121A6B, Buenos Aires, Argentina.
authors.forename: Verónica
authors.initials: V
authors.lastname: Pastor
authors.forename: María Estela
authors.initials: ME
authors.lastname: Andrés
authors.forename: Ramón O
authors.initials: RO
authors.lastname: Bernabeu
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects*; D007279:Injections, Subcutaneous; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D012201:Reward; D013997:Time Factors
chemical_list: D009538:Nicotine