title: The role of acetaldehyde in ethanol reinforcement assessed by Pavlovian conditioning in newborn rats.
abstract: BACKGROUND
  Animal studies indicate that central acetaldehyde, dependent on catalase metabolism of ethanol (EtOH), modulates ethanol reinforcement. Brain catalase activity and acetaldehyde (ACD) production are significantly higher in rat pups compare d with adults. Interestingly, infant rats show high EtOH affinity for alcohol consumption and are particularly sensitive to the drug's reinforcing effects.
  
  
  OBJECTIVE
  We tested whether central ACD is necessary and sufficient to induce appetitive conditioning in newborn rats through the artificial nipple technique.
  
  
  METHODS
  Vehicle, EtOH (100 mg%), and acetaldehyde (0.35 μmol) were administered into the cisterna magna (1 μl). Half of the animals also received a central administration of 75 μg (experiment 1) or 40 μg of D-penicillamine (experiment 2). Afterwards, pups were exposed to an olfactory cue (conditioned stimulus). One hour later, neonates were tested with an artificial nipple in the presence of the conditioned cue. Nipple attachment duration, mean grasp duration, and number of nipple disengagements served as dependent variables.
  
  
  RESULTS
  Positive responses to the scented nipple occurred in neonates conditioned with EtOH or ACD (experiments 1 and 2). In experiment 1, there were indications that D-penicillamine weakened the reinforcing effects of EtOH and ACD. In experiment 2, D-penicillamine (40 μg) significantly inhibited appetitive conditioned responses dependent upon EtOH or ACD.
  
  
  CONCLUSIONS
  Appetitive conditioning was observed when employing either central EtOH or ACD as unconditioned stimuli. Central abduction of ACD inhibited conditioned appetitive responsiveness to the surrogate nipple. Central ACD is involved in the determination or modulation of EtOH's motivational properties during early stages in development.
authors.affiliation: Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET), P.O. BOX 389, Friuli 2434, 5016 Córdoba, Argentina. smarch@immf.uncor.edu
authors.forename: Samanta M
authors.initials: SM
authors.lastname: March
authors.forename: Paula
authors.initials: P
authors.lastname: Abate
authors.forename: Norman E
authors.initials: NE
authors.lastname: Spear
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Molina
mesh_terms: D000079:Acetaldehyde / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D002374:Catalase / Q000378:metabolism*; D003214:Conditioning, Classical / Q000187:drug effects; D000431:Ethanol / Q000008:administration & dosage* / Q000378:metabolism; D005260:Female; D008297:Male; D009042:Motivation; D010396:Penicillamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012054:Reinforcement, Psychology
chemical_list: D000431:Ethanol; D002374:Catalase; D010396:Penicillamine; D000079:Acetaldehyde