title: One-trial behavioral sensitization in preweanling rats: differential effects of cocaine, methamphetamine, methylphenidate, and D-amphetamine.
abstract: BACKGROUND
  Preweanling rats exhibit robust one-trial cocaine-induced behavioral sensitization; however, it is uncertain whether other psychostimulants can also induce sensitization in young rats using the one-trial procedure.
  
  
  OBJECTIVE
  The purpose of this study was to determine whether methamphetamine, methylphenidate, and D: -amphetamine are capable of inducing one-trial locomotor sensitization in preweanling rats.
  
  
  METHODS
  In a series of four experiments, rats were pretreated with cocaine (30 mg/kg), methamphetamine (2-12 mg/kg), methylphenidate (5-20 mg/kg), or amphetamine (5 mg/kg) before being placed in a novel activity chamber or the home cage on PD 19. Rats were then challenged with the same psychostimulant (20 mg/kg cocaine, 1-8 mg/kg methamphetamine, 2.5-7.5 mg/kg methylphenidate, or 1-2 mg/kg amphetamine) on PD 21, with distance traveled being measured for 180 min. In a separate experiment, rats were pretreated with methamphetamine on PD 16-19 and challenged with methamphetamine on PD 21.
  
  
  RESULTS
  Only cocaine, but not various dose combinations of other psychostimulants, was able to produce one-trial behavioral sensitization in preweanling rats. Context-dependent locomotor sensitization was also evident if rats were pretreated with methamphetamine on PD 16-19 and tested on PD 21.
  
  
  CONCLUSIONS
  It is uncertain why only cocaine was able to induce one-trial locomotor sensitization in preweanling rats, but it is possible that: (a) the neural circuitry mediating sensitization differs according to psychostimulant, (b) cocaine is more readily associated with environmental contexts than other psychostimulants, or (c) affinity and pharmacokinetic factors may underlie cocaine's ability to induce one-trial behavioral sensitization in preweanling rats.
authors.affiliation: Department of Psychology, California State University, 5500 University Parkway, San Bernardino, CA 92407, USA. smcdouga@csusb.edu
authors.forename: Sanders A
authors.initials: SA
authors.lastname: McDougall
authors.forename: Olga O
authors.initials: OO
authors.lastname: Kozanian
authors.forename: Venuz Y
authors.initials: VY
authors.lastname: Greenfield
authors.forename: Leslie R
authors.initials: LR
authors.lastname: Horn
authors.forename: Arnold
authors.initials: A
authors.lastname: Gutierrez
authors.forename: Alena
authors.initials: A
authors.lastname: Mohd-Yusof
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Castellanos
mesh_terms: D000375:Aging / Q000187:drug effects / Q000523:psychology; D000818:Animals; D000833:Animals, Suckling; D001522:Behavior, Animal / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003042:Cocaine / Q000494:pharmacology*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D008774:Methylphenidate / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014886:Weaning
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate; D008694:Methamphetamine; D003042:Cocaine; D003913:Dextroamphetamine