title: Long-term effects of exposure to methamphetamine in adolescent rats.
abstract: BACKGROUND
  Flexible cognition is a set of processes mediated by the prefrontal cortex (PFC), an area of the brain that continues to develop during adolescence and into adulthood. Adult rodents exhibit impairments specific to reversal learning across various dosing regimens of methamphetamine (mAMPH). For adolescent rodents, ongoing PFC development can be assessed by discrimination reversal learning, a task dependent on frontostriatal integrity. The task may also index an increased vulnerability for mAMPH sampling in adulthood.
  
  
  METHODS
  The purpose of the present study was to investigate the long-term effects of escalating, adolescent mAMPH exposure on reversal learning, a PFC-dependent task (Experiment 1) and the likelihood of later sampling of mAMPH in adulthood (Experiment 2).
  
  
  RESULTS
  Unlike previous research in adult-treated rats, our results show more generalized learning impairments after adolescent mAMPH exposure to include both attenuated visual discrimination as well as reversal learning. Additionally, we found that rats pre-exposed to mAMPH during adolescence consumed significantly more drug in adulthood. Intake of mAMPH was positively correlated with this learning. Taken together, these findings show that even modest exposure to mAMPH during adolescence may induce general learning impairments in adulthood, and an enduring sensitivity to the effects of mAMPH.
authors.affiliation: University of California, Los Angeles, Department of Psychology, Los Angeles, CA, USA.
authors.forename: Tony
authors.initials: T
authors.lastname: Ye
authors.affiliation: University of California, Los Angeles, Department of Psychology, Los Angeles, CA, USA.
authors.forename: Hilda
authors.initials: H
authors.lastname: Pozos
authors.affiliation: Oregon Health & Science University, Veterans Affairs Medical Center and Methamphetamine Abuse Research Center, Portland, OR, USA.
authors.forename: Tamara J
authors.initials: TJ
authors.lastname: Phillips
authors.affiliation: University of California, Los Angeles, Department of Psychology, Los Angeles, CA, USA. Electronic address: aizquie@psych.ucla.edu.
authors.forename: Alicia
authors.initials: A
authors.lastname: Izquierdo
mesh_terms: D000375:Aging / Q000187:drug effects; D000818:Animals; D002755:Choice Behavior / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects*; D007859:Learning Disabilities / Q000139:chemically induced*; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage / Q000009:adverse effects*; D051381:Rats; D012193:Reversal Learning / Q000187:drug effects*; D012646:Self Administration
chemical_list: D008694:Methamphetamine
keywords: Adolescence; Cognitive flexibility; Frontal cortex; Plasticity; Reversal learning