title: Effect of norbinaltorphimine on ∆⁹-tetrahydrocannabinol (THC)-induced taste avoidance in adolescent and adult Sprague-Dawley rats.
abstract: BACKGROUND
  The aversive effects of ∆(9)-tetrahydrocannabinol (THC) are mediated by activity at the kappa opioid receptor (KOR) as assessed in adult animals; however, no studies have assessed KOR involvement in the aversive effects of THC in adolescents. Given that adolescents have been reported to be insensitive to the aversive effects induced by KOR agonists, a different mechanism might mediate the aversive effects of THC in this age group.
  
  
  OBJECTIVE
  The present study was designed to assess the impact of KOR antagonism on the aversive effects of THC in adolescent and adult rats using the conditioned taste avoidance (CTA) procedure.
  
  
  METHODS
  Following a single pretreatment injection of norbinaltorphimine (norBNI; 15 mg/kg), CTAs induced by THC (0, 0.56, 1.0, 1.8, and 3.2 mg/kg) were assessed in adolescent (n = 84) and adult (n = 83) Sprague-Dawley rats.
  
  
  RESULTS
  The KOR antagonist, norBNI, had weak and inconsistent effects on THC-induced taste avoidance in adolescent rats in that norBNI both attenuated and strengthened taste avoidance dependent on dose and trial. norBNI had limited impact on the final one-bottle avoidance and no effects on the two-bottle preference test. Interestingly, norBNI had no effect on THC-induced taste avoidance in adult rats as well.
  
  
  CONCLUSIONS
  That norBNI had no significant effect on THC-induced avoidance in adults, and a minor and inconsistent effect in adolescents demonstrates that the aversive effects of THC are not mediated by KOR activity as assessed by the CTA design in Sprague-Dawley rats.
authors.affiliation: Pscyhopharmacology Laboratory, Department of Psychology, American University, 4400 Massachusetts Avenue NW, Washington, DC, 20016, USA, flaxshaun@gmail.com.
authors.forename: Shaun M
authors.initials: SM
authors.lastname: Flax
authors.forename: Alison G P
authors.initials: AG
authors.lastname: Wakeford
authors.forename: Kejun
authors.initials: K
authors.lastname: Cheng
authors.forename: Kenner C
authors.initials: KC
authors.lastname: Rice
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Riley
mesh_terms: D000375:Aging / Q000523:psychology; D000818:Animals; D019167:Appetite Stimulants / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D013759:Dronabinol / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D008297:Male; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000037:antagonists & inhibitors; D013649:Taste / Q000187:drug effects*; D055697:Taste Perception / Q000187:drug effects
chemical_list: D019167:Appetite Stimulants; D009292:Narcotic Antagonists; D017473:Receptors, Opioid, kappa; C051844:norbinaltorphimine; D009271:Naltrexone; D013759:Dronabinol