title: MDMA enhances hippocampal-dependent learning and memory under restrictive conditions, and modifies hippocampal spine density.
abstract: OBJECTIVE
  Addictive drugs produce forms of structural plasticity in the nucleus accumbens and prefrontal cortex. The aim of this study was to investigate the impact of chronic MDMA exposure on pyramidal neurons in the CA1 region of hippocampus and drug-related spatial learning and memory changes.
  
  
  RESULTS
  Adolescent rats were exposed to saline or MDMA in a regime that mimicked chronic administration. One week later, when acquisition or reference memory was evaluated in a standard Morris water maze (MWM), no differences were obtained between groups. However, MDMA-exposed animals performed better when the MWM was implemented under more difficult conditions. Animals of MDMA group were less anxious and were more prepared to take risks, as in the open field test they ventured more frequently into the central area. We have demonstrated that MDMA caused an increase in brain-derived neurotrophic factor (BDNF) expression. When spine density was evaluated, MDMA-treated rats presented a reduced density when compared with saline, but overall, training increased the total number of spines, concluding that in MDMA-group, training prevented a reduction in spine density or induced its recovery.
  
  
  CONCLUSIONS
  This study provides support for the conclusion that binge administration of MDMA, known to be associated to neurotoxic damage of hippocampal serotonergic terminals, increases BDNF expression and stimulates synaptic plasticity when associated with training. In these conditions, adolescent rats perform better in a more difficult water maze task under restricted conditions of learning and memory. The effect on this task could be modulated by other behavioural changes provoked by MDMA.
authors.affiliation: Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section) and Institute of Biomedicine (IBUB), University of Barcelona, Avda. Joan XXIII s/n, Barcelona, 08028, Spain.
authors.forename: Sònia
authors.initials: S
authors.lastname: Abad
authors.forename: Alberto
authors.initials: A
authors.lastname: Fole
authors.forename: Nuria
authors.initials: N
authors.lastname: del Olmo
authors.forename: David
authors.initials: D
authors.lastname: Pubill
authors.forename: Mercè
authors.initials: M
authors.lastname: Pallàs
authors.forename: Fèlix
authors.initials: F
authors.lastname: Junyent
authors.forename: Jorge
authors.initials: J
authors.lastname: Camarasa
authors.forename: Antonio
authors.initials: A
authors.lastname: Camins
authors.forename: Elena
authors.initials: E
authors.lastname: Escubedo
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000187:drug effects*; D049229:Dendritic Spines / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000097:blood / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018817:N-Methyl-3,4-methylenedioxyamphetamine