title: Alterations of naltrexone-induced conditioned place avoidance by pre-exposure to high fructose corn syrup or heroin in Sprague-Dawley rats.
abstract: BACKGROUND
  It has been suggested that withdrawal from sugar produces a set of symptoms that resemble those observed following withdrawal from opiate drugs.
  
  
  OBJECTIVE
  This study explored naltrexone-induced withdrawal in animals pre-exposed to acute, chronic, and intermittent high fructose corn syrup (HFCS) or acute and chronic heroin administration.
  
  
  METHODS
  Experiment 1 examined conditioned place avoidance (CPA) induced by different doses of naltrexone (0.01-1 mg/kg) in naïve male Sprague-Dawley rats. In experiment 2, rats received continuous or intermittent home cage HFCS access (0 or 50 %) prior to conditioning with 1 mg/kg naltrexone. In experiment 3, HFCS ingestion was increased by food restriction and rats were conditioned with 3 mg/kg naltrexone. In experiment 4, the timing and quantity of HFCS ingestion (0, 0.5, 1, 2 g/kg) was controlled by intragastric administration, and rats were conditioned with 1 mg/kg naltrexone. In experiment 5, rats received acute (2 mg/kg) or chronic heroin (3.5 mg/kg/day) prior to conditioning with 1 mg/kg naltrexone.
  
  
  RESULTS
  Administration of naltrexone produced moderate conditioned place avoidance in naïve rats. Importantly, acute, continuous, and intermittent HFCS pre-exposure did not significantly amplify this effect, but acute and chronic heroin pre-exposure did.
  
  
  CONCLUSIONS
  As assessed by CPA, these results in rats fail to support the hypothesis that an opioid antagonist can precipitate similar affective withdrawal states following pre-exposure to sugars and opiates.
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Stephen
authors.initials: S
authors.lastname: Daniels
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Marshall
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON, N1G 2W1, Canada. fleri@uoguelph.ca.
authors.forename: Francesco
authors.initials: F
authors.lastname: Leri
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005508:Food Deprivation; D003932:Heroin / Q000494:pharmacology*; D066248:High Fructose Corn Syrup / Q000494:pharmacology*; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013375:Substance Withdrawal Syndrome / Q000523:psychology
chemical_list: D066248:High Fructose Corn Syrup; D009292:Narcotic Antagonists; D009294:Narcotics; D009271:Naltrexone; D003932:Heroin
keywords: Conditioned place avoidance; Heroin; High fructose corn syrup; Naltrexone