title: The effects of nicotine exposure during Pavlovian conditioning in rats on several measures of incentive motivation for a conditioned stimulus paired with water.
abstract: BACKGROUND
  Nicotine enhances approach toward and operant responding for conditioned stimuli (CSs), but the effect of exposure during different phases of Pavlovian incentive learning on these measures remains to be determined.
  
  
  OBJECTIVE
  These studies examined the effects of administering nicotine early, late or throughout Pavlovian conditioning trials on discriminated approach behavior, nicotine-enhanced responding for conditioned reinforcement, extinction, and the reinstatement of responding for conditioned reinforcement. We also tested the effect of nicotine on approach to a lever-CS in a Pavlovian autoshaping procedure and for this CS to serve as a conditioned reinforcer.
  
  
  METHODS
  Thirsty rats were exposed to 13 conditioning sessions where a light/tone CS was paired with the delivery of water. Nicotine was administered either prior to the first or last seven sessions, or throughout the entire conditioning procedure. Responding for conditioned reinforcement, extinction, and the reinstatement of responding by the stimulus and nicotine were compared across exposure groups. Separately, the effects of nicotine on conditioned approach toward a lever-CS during autoshaping, and responding for that CS as a conditioned reinforcer, were examined.
  
  
  RESULTS
  Nicotine exposure was necessary for nicotine-enhanced responding for conditioned reinforcement and the ability for nicotine and the stimulus to additively reinstate responding on the reinforced lever. Nicotine increased contacts with a lever-CS during autoshaping, and removal of nicotine abolished this effect. Prior nicotine exposure was necessary for nicotine-enhanced responding reinforced by the lever.
  
  
  CONCLUSIONS
  Enhancements in the motivating properties of CSs by nicotine occur independently from duration and timing effects of nicotine exposure during conditioning.
authors: Department of Psychology, University of Toronto Centre of Addiction and Mental Health, 250 College Street, Toronto, ON, Canada, M5T 1R8, elizabethguy.glenn@utoronto.ca.
authors: Elizabeth Glenn
authors: EG
authors: Guy
authors: Paul J
authors: PJ
authors: Fletcher
mesh_terms: D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects*; D003463:Cues; D005108:Extinction, Psychological / Q000187:drug effects; D006040:Goals; D008297:Male; D009042:Motivation / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D020318:Rats, Long-Evans; D012054:Reinforcement, Psychology; D013647:Task Performance and Analysis; D013997:Time Factors; D014867:Water / Q000008:administration & dosage*; D014868:Water Deprivation
chemical_list: D018722:Nicotinic Agonists; D014867:Water; D009538:Nicotine