title: Meal schedule influences food restriction-induced locomotor sensitization to methamphetamine.
abstract: BACKGROUND
  Traditional protocols for inducing sensitization to psychostimulants use an intermittent or "binge"-like drug administration, and binge eating behavior is comorbid with drug abuse in humans. Food restriction increases the reinforcing properties and self-administration of many drugs of abuse.
  
  
  OBJECTIVE
  The present study tested the hypotheses that (1) food restriction induces sensitization to the locomotor stimulation observed in response to methamphetamine and (2) a binge-like feeding schedule during food restriction produces increased sensitization compared to equally restricted mice fed in three daily meals.
  
  
  METHODS
  Male DBA/2J mice were fed ad libitum or were food restricted to either an 8% or 16% loss of body weight. Additionally, the food-restricted mice were divided into two groups that were fed in either one meal (binge) or three equal-sized meals (meal). After the reduced body weight was stable, mice were tested for locomotor activity following saline and methamphetamine (1 mg/kg) injections.
  
  
  RESULTS
  Both 16% body weight loss groups exhibited sensitization to methamphetamine. Opposite to our hypothesis, the 8% meal but not the 8% binge food-restricted group demonstrated locomotor sensitization. Serum corticosterone levels were significantly higher in the meal-fed groups when compared to the binge- and ad libitum-fed groups.
  
  
  CONCLUSIONS
  These results support a role for feeding schedule and plasma corticosterone levels in food restriction-induced enhancement of the effects of methamphetamine.
authors.affiliation: Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MSC7756, San Antonio, TX 78229, USA.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Sharpe
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Klaus
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Beckstead
mesh_terms: D000818:Animals; D002032:Bulimia / Q000097:blood; D003345:Corticosterone / Q000097:blood; D005247:Feeding Behavior / Q000187:drug effects*; D005508:Food Deprivation; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D051379:Mice; D008811:Mice, Inbred DBA; D009043:Motor Activity / Q000187:drug effects*; D012055:Reinforcement Schedule
chemical_list: D008694:Methamphetamine; D003345:Corticosterone