title: The effects of rearing condition on methamphetamine self-administration and cue-induced drug seeking.
abstract: BACKGROUND
  Little is known about the effect of different rearing conditions on the effects of methamphetamine and whether the introduction of enriched rearing conditions at different stages of development could produce different behavioral outcomes.
  
  
  METHODS
  In Experiment 1, rats were reared in either enriched (EE) or isolated environments (IE) from PND 21 to 60. In Experiment 2, two groups of animals were handled in the same fashion as those in Experiment 1. Additional two groups were housed in IE during the first 20 or 30 days and then housed under EE for the remaining 20 or 10 days respectively. Locomotor activity and Morris Water Maze were tested. The effects of rearing conditions on methamphetamine (METH) self-administration were investigated.
  
  
  RESULTS
  IE animals exhibited higher levels of locomotion than EE animals, but EE animals showed enhanced Morris water maze performance. Animals reared in IE for 30 and 40 days more readily acquired METH self-administration, compared to those reared in IE for 20 and in EE for 40 days respectively. However, the effect of rearing conditions was only seen at the lowest dose tested under FR schedule and breakpoints obtained from PR schedule were not significantly affected. Those reared in IE for 20 and EE for 40 days animals produced significantly fewer responses during the extinction and cue-induced reinstatement of METH self-administration, compared with animals reared in IE for 30 and 40 days, respectively.
  
  
  CONCLUSIONS
  Rearing condition plays a significant role in locomotor activity, spatial memory and behavioral effects of METH.
authors.affiliation: Ningbo University School of Medicine, PR China.
authors.forename: Xiuyi
authors.initials: X
authors.lastname: Lü
authors.forename: Chun
authors.initials: C
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Baomiao
authors.initials: B
authors.lastname: Ma
authors.forename: Zhongze
authors.initials: Z
authors.lastname: Lou
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.forename: Junfeng
authors.initials: J
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Thomas J R
authors.initials: TJ
authors.lastname: Beveridge
authors.forename: Wenhua
authors.initials: W
authors.lastname: Zhou
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D003463:Cues; D058999:Drug-Seeking Behavior / Q000502:physiology*; D004777:Environment; D006799:Housing, Animal; D008297:Male; D008568:Memory / Q000187:drug effects; D008694:Methamphetamine / Q000008:administration & dosage*; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012646:Self Administration
chemical_list: D000697:Central Nervous System Stimulants; D008694:Methamphetamine