title: Effect of preexposure on methylphenidate-induced taste avoidance and related BDNF/TrkB activity in the insular cortex of the rat.
abstract: BACKGROUND
  Exogenous brain-derived neurotrophic factor (BDNF) in the insular cortex (IC) is known to influence conditioned taste avoidance (CTA) learning, but little is known of its endogenous role in the phenomenon. Preexposure to many abusable compounds attenuates their ability to induce CTA, thus providing a possible platform from which to further elucidate the endogenous role of IC BDNF in CTA.
  
  
  OBJECTIVE
  The role of IC BDNF in CTA learning was examined by assessing the effect of preexposure to methylphenidate (MPH) on MPH-induced CTA, followed by expression between preexposure groups of BDNF in the IC, central nucleus of the amygdala (CeA), and the nucleus accumbens (NAc).
  
  
  METHODS
  Following preexposure to MPH (18 mg/kg), CTAs induced by MPH (0, 10, 18, and 32 mg/kg) were assessed in adult male Sprague-Dawley rats (n = 64). In separate groups (n = 31), differences in BDNF and tropomyosin-related kinase receptor-B (TrkB) were assessed using Western blots following similar preexposure and conditioning procedures.
  
  
  RESULTS
  Preexposure to MPH significantly blunted MPH-CTA compared to preexposure to vehicle. Unexpectedly, there were no significant effects of MPH on BDNF activity following CTA, but animals preexposed to MPH exhibited decreased activity in the CeA and enhanced activity in the IC and NAc.
  
  
  CONCLUSIONS
  Preexposure to MPH attenuates its aversive effects on subsequent presentations, and BDNF's impact on CTA learning may be dependent upon its temporal relation to other CTA-related intracellular cascades.
authors.affiliation: Psychopharmacology Laboratory, Department of Psychology, American University, Washington, DC, 20016, USA, bradley.wetzell@american.edu.
authors.forename: B Bradley
authors.initials: BB
authors.lastname: Wetzell
authors.forename: Mirabella M
authors.initials: MM
authors.lastname: Muller
authors.forename: Shaun M
authors.initials: SM
authors.lastname: Flax
authors.forename: Heather E
authors.initials: HE
authors.lastname: King
authors.forename: Kathleen
authors.initials: K
authors.lastname: DeCicco-Skinner
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Riley
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D020813:Receptor, trkB / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013649:Taste / Q000187:drug effects*; D055697:Taste Perception / Q000187:drug effects
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D018765:Dopamine Uptake Inhibitors; D008774:Methylphenidate; D020813:Receptor, trkB