title: The effects of L-arginine on spatial memory and synaptic plasticity impairments induced by lipopolysaccharide.
abstract: BACKGROUND
  An important role of nitric oxide (NO) in neuroinflammation has been suggested. It is also suggested that NO has a critical role in learning and memory. Neuro-inflammation induced by lipopolysaccharide (LPS) has been reported that deteriorates learning and memory. The effect of L-arginine (LA) as a precursor of NO on LPS-induced spatial learning and memory and neuronal plasticity impairment was evaluated.
  
  
  METHODS
  The animals were grouped into: (1) Control, (2) LPS, (3) LA-LPS, and (4) LA. The rats received intraperitoneally LPS (1 mg/kg) 2 h before experiments and LA (200 mg/kg) 30 min before LPS. The animals were examined in Morris water maze (MWM). Long-term potentiation (LTP) from CA1 area of the hippocampus was also assessed by 100 Hz stimulation in the ipsilateral Schaffer collateral pathway.
  
  
  RESULTS
  In MWM, time latency and traveled path were higher in LPS group than the control group (P < 0.001) whereas in LA-LPS group they were shorter than LPS group (P < 0.001). The amplitude and slope of field excitatory postsynaptic potential (fEPSP) decreased in LPS group compared to control group (P < 0.05 and P < 0.01) whereas, there was not any significant difference in these parameters between LPS and LA-LPS groups.
  
  
  CONCLUSIONS
  Administration of LPS impaired spatial memory and synaptic plasticity. Although LA ameliorated deleterious effects of LPS on learning of spatial tasks, it could not restore LPS-induced LTP impairment.
authors.affiliation: Neurocognitive Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Anaeigoudari
authors.affiliation: Neurocognitive Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mohammad Naser
authors.initials: MN
authors.lastname: Shafei
authors.affiliation: Department of Biochemistry, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Soukhtanloo
authors.affiliation: Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Sadeghnia
authors.affiliation: Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Parham
authors.initials: P
authors.lastname: Reisi
authors.affiliation: Immunology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Nosratabadi
authors.affiliation: Neurogenic Inflammation Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Sepehr
authors.initials: S
authors.lastname: Behradnia
authors.affiliation: Neurogenic Inflammation Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Hosseini
keywords: L-arginine; lipopolysaccharide; long-term potentiation; memory