title: Methamphetamine-induced behavioral sensitization in a rodent model of posttraumatic stress disorder.
abstract: BACKGROUND
  Single prolonged stress (SPS) is a rodent model of posttraumatic stress disorder (PTSD)-like characteristics. Given that PTSD is frequently comorbid with substance abuse and dependence, including methamphetamine (METH), the current study sought to investigate the effects of SPS on METH-induced behavioral sensitization.
  
  
  METHODS
  In experiment 1, Sprague-Dawley rats were subject to SPS or control treatment and subsequently tested across four sessions of an escalating METH dosing paradigm. METH was injected (i.p.) in escalating doses (0, 0.032, 0.1, 0.32, 1.0, and 3.2mg/kg; dissolved in saline) every 15min and ambulatory activity was recorded. In experiment 2, SPS and control treated rats were injected (i.p.) with either saline or METH (5mg/kg) for five consecutive daily sessions and tested for stereotypy as well as ambulatory activity. Two days later, all animals were injected with a challenge dose of METH (2.5mg/kg) and again tested for activity.
  
  
  RESULTS
  No differences in the acute response to METH were observed between SPS and controls. SPS enhanced METH induced ambulatory activity across sessions, compared to controls. METH-induced stereotypy increased across sessions, indicative of behavioral sensitization; however, SPS attenuated, not enhanced, this effect suggesting that SPS may prevent the development of stereotypy sensitization.
  
  
  CONCLUSIONS
  Collectively, results show that SPS increases repeated METH-induced ambulatory activity while preventing the transition across sessions from ambulatory activity to stereotypy. These findings suggest that SPS alters drug-induced neuroplasticity associated with behavioral sensitization to METH, which may reflect an effect on the shared neurocircuitry underlying PTSD and substance dependence.
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA. aeagle@med.wayne.edu
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Eagle
authors.forename: Shane A
authors.initials: SA
authors.lastname: Perrine
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D008297:Male; D008694:Methamphetamine / Q000633:toxicity*; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D019956:Stereotypic Movement Disorder / Q000139:chemically induced / Q000523:psychology; D013313:Stress Disorders, Post-Traumatic / Q000139:chemically induced* / Q000523:psychology*
chemical_list: D008694:Methamphetamine