title: The effects of tamoxifen on spatial and nonspatial learning and memory impairments induced by scopolamine and the brain tissues oxidative damage in ovariectomized rats.
abstract: BACKGROUND
  Modulatory effects of tamoxifen (TAM) on the central nervous system have been reported. The effects of TAM on spatial and nonspatial learning and memory impairments induced by scopolamine and the brain tissues oxidative damage was investigated.
  
  
  METHODS
  The ovariectomized (OVX) rats were divided and treated: (1) Control (saline), (2) scopolamine (Sco; 2 mg/kg, 30 min before behavioral tests), (3-5) Sco-TAM 1, Sco-TAM 3 and Sco-TAM 10. TAM (1, 3 or 10 mg/kg; i.p.) was daily administered for 6 weeks.
  
  
  RESULTS
  In Morris water maze (MWM), both the latency and traveled distance in the Sco-group were higher than control (P < 0.001) while, in the Sco-TAM 10 group it was lower than Sco-group (P < 0.05). In passive avoidance test, the latency to enter the dark compartment was higher than control (P < 0.05 - P < 0.01). Pretreatment by all three doses of TAM prolonged the latency to enter the dark compartment compared to Sco-group (P < 0.05 - P < 0.001). The brain tissues malondialdehyde (MDA) concentration was increased while, superoxide dismutase activity (SOD) decreased in the Sco-group compared to control (P < 0.05 - P < 0.01). Pretreatment by TAM lowered the concentration of MDA while, increased SOD compared to Sco-group (P < 0.05 - P < 0.001).
  
  
  CONCLUSIONS
  It is suggested that TAM prevents spatial and nonspatial learning and memory impairments induced by scopolamine in OVX rats. The possible mechanism(s) might at least in part be due to protection against the brain tissues oxidative damage.
authors.affiliation: Department of Physiology, Shahid Sadoghi University of Medical Sciences, Yazd, Iran.
authors.forename: Sareh
authors.initials: S
authors.lastname: Karimi
authors.affiliation: Department of Physiology, Shahid Sadoghi University of Medical Sciences, Yazd, Iran.
authors.forename: Seyed Hassan
authors.initials: SH
authors.lastname: Hejazian
authors.affiliation: Neurogenic Inflammation Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Vajiheh
authors.initials: V
authors.lastname: Alikhani
authors.affiliation: Neurocognitive Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Hosseini
keywords: Memory; lipid peroxidation; morris water maze; scopolamine; superoxide dismutase; tamoxifen