title: The nitric oxide donor sodium nitroprusside attenuates recognition memory deficits and social withdrawal produced by the NMDA receptor antagonist ketamine and induces anxiolytic-like behaviour in rats.
abstract: BACKGROUND
  Experimental evidence indicates that the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist ketamine impairs cognition and can mimic certain aspects of positive and negative symptoms of schizophrenia in rodents. Nitric oxide (NO) is considered as an intracellular messenger in the brain, and its abnormalities have been linked to schizophrenia.
  
  
  OBJECTIVE
  The present study was designed to investigate the ability of the NO donor sodium nitroprusside (SNP) to counteract schizophrenia-like behavioural deficits produced by ketamine in rats.
  
  
  METHODS
  The ability of SNP to reverse ketamine-induced memory deficits and social withdrawal were assessed using the novel object recognition task (NORT) and the social interaction test, respectively. Furthermore, since anxiety disorders are noted to occur commonly in schizophrenics, the effects of SNP on anxiety-like behaviour were examined using the light/dark test. Locomotor activity was also assessed as an independent measure of the potential motoric effects of this NO donor.
  
  
  RESULTS
  SNP (0.3 and 1 mg/kg) reversed ketamine (3 mg/kg)-induced short-term recognition memory deficits. SNP (1 mg/kg) counteracted the ketamine (8 mg/kg)-induced social isolation in the social interaction test. The anxiolytic-like effects in the light/dark test of SNP (1 mg/kg) cannot be attributed to changes in locomotor activity.
  
  
  CONCLUSIONS
  Our findings illustrate a functional interaction between the nitrergic and glutamatergic system that may be of relevance for schizophrenia-like behavioural deficits. The data also suggest a role of NO in anxiety.
authors.affiliation: Department of Pharmacology, School of Medicine, Faculty of Health Sciences, University of Thessaly, Biopolis, Panepistimiou 3, 415-00, Larissa, Greece.
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Trevlopoulou
authors.affiliation: Department of Pharmacology, School of Medicine, Faculty of Health Sciences, University of Thessaly, Biopolis, Panepistimiou 3, 415-00, Larissa, Greece.
authors.forename: Ntilara
authors.initials: N
authors.lastname: Touzlatzi
authors.affiliation: Department of Pharmacology, School of Medicine, Faculty of Health Sciences, University of Thessaly, Biopolis, Panepistimiou 3, 415-00, Larissa, Greece. npitsikas@med.uth.gr.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pitsikas
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D001007:Anxiety / Q000139:chemically induced; D001522:Behavior, Animal / Q000187:drug effects*; D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine; D008297:Male; D008569:Memory Disorders / Q000139:chemically induced / Q000188:drug therapy*; D009043:Motor Activity / Q000187:drug effects; D016202:N-Methylaspartate / Q000494:pharmacology; D020030:Nitric Oxide Donors / Q000494:pharmacology* / Q000627:therapeutic use; D009599:Nitroprusside / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D021641:Recognition, Psychology / Q000187:drug effects*; D012919:Social Behavior
chemical_list: D014151:Anti-Anxiety Agents; D018691:Excitatory Amino Acid Antagonists; D020030:Nitric Oxide Donors; D016194:Receptors, N-Methyl-D-Aspartate; D009599:Nitroprusside; D016202:N-Methylaspartate; D007649:Ketamine
keywords: Anxiety; Ketamine; Rat; Schizophrenia; Sodium nitroprusside