title: Acquisition and reconditioning of ethanol-induced conditioned place preference in mice is blocked by the H₂O₂ scavenger alpha lipoic acid.
abstract: BACKGROUND
  Hydrogen peroxide (H2O2) is the co-substrate used by catalase to metabolize ethanol to acetaldehyde in the brain. This centrally formed acetaldehyde has been involved in several ethanol-related behaviors.
  
  
  OBJECTIVE
  The present research evaluated the effect of the H2O2 scavenger, alpha lipoic acid (LA), on the acquisition and reconditioning of ethanol-induced conditioned place preference (CPP).
  
  
  METHODS
  Mice received pairings of a distinctive floor stimulus (CS+) associated with intraperitoneal injections of ethanol (2.5 g/kg). On alternate days, animals received pairings of a different floor stimulus (CS-) associated with saline injections. A different group of animals received pairings with the (CS-) associated with saline injections, and on alternate days they received LA (100 mg/kg) injected 30 min prior to ethanol (2.5 g/kg) administration paired with the (CS+). A preference test assessed the effect of LA on the acquisition of ethanol-induced CPP. A similar procedure was followed to study the effect of LA on the acquisition of cocaine- and morphine-induced CPP. A separate experiment evaluated the effect of LA on the reconditioning of ethanol-induced CPP. In addition, we investigated the consequence of LA administration on central H2O2 levels.
  
  
  RESULTS
  LA selectively blocked the acquisition of ethanol-induced CPP. Moreover, this compound impaired the reconditioning of ethanol-induced CPP. Additionally, we found that LA diminished H2O2 levels in the brain.
  
  
  CONCLUSIONS
  These data suggest that a decline in H2O2 availability by LA might impede the formation of brain ethanol-derived acetaldehyde by catalase, which results in an impairment of the rewarding properties of ethanol.
authors.affiliation: Area de Psicobiologia, Universitat Jaume I, Avenida Sos Baynat s/n, 12071, Castellón, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Ledesma
authors.forename: Carlos M G
authors.initials: CM
authors.lastname: Aragon
mesh_terms: D000079:Acetaldehyde / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology; D003214:Conditioning, Classical / Q000187:drug effects*; D000431:Ethanol / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D051379:Mice; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology; D012201:Reward; D008063:Thioctic Acid / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D000431:Ethanol; D008063:Thioctic Acid; D009020:Morphine; D006861:Hydrogen Peroxide; D000079:Acetaldehyde; D003042:Cocaine