title: The effect of combined treatment with escitalopram and risperidone on the MK-801-induced changes in the object recognition test in mice.
abstract: BACKGROUND
  Atypical antipsychotic drugs have some efficacy in alleviating the negative and some cognitive symptoms of schizophrenia but those effects are small and mechanisms of this action are still unknown. A few clinical reports have suggested that the antidepressant drugs, especially selective serotonin reuptake inhibitors (SSRI) are able to augment the activity of atypical antipsychotic drugs, thus effectively improving treatment of the negative and some cognitive symptoms of schizophrenia.
  
  
  METHODS
  In the present study, we evaluated the effect of escitalopram (SSRI) and risperidone (an atypical antipsychotic drug), given separately or jointly, on the effect of MK-801 (a NMDA receptor antagonist) given before to the first introductory session, in the object recognition memory test. The mice were tested for the ability to discriminate between an old, familiar and a novel object. Escitalopram and risperidone were given 30min before MK-801, and MK-801 was administered 30min before the first introductory session. Memory retention was evaluated 90min after the introductory session.
  
  
  RESULTS
  The obtained results showed that MK-801 (0.2mg/kg) decreased memory retention when given before the introductory session. Risperidone at a higher dose (0.1mg/kg) reversed that effect. Co-treatment with an ineffective dose of risperidone (0.01mg/kg) and escitalopram (5 or 10mg/kg) abolished the deficit of object recognition memory induced by MK-801.
  
  
  CONCLUSIONS
  The obtained results suggest that escitalopram may enhance the antipsychotic-like effect of risperidone in the animal tests used for evaluation of some cognitive symptoms of schizophrenia.
authors.affiliation: Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland. Electronic address: rogoz@if-pan.krakow.pl.
authors.forename: Zofia
authors.initials: Z
authors.lastname: Rogóż
authors.affiliation: Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kamińska
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000008:administration & dosage; D015283:Citalopram / Q000008:administration & dosage*; D016291:Dizocilpine Maleate / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D018691:Excitatory Amino Acid Antagonists / Q000633:toxicity; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D008297:Male; D008569:Memory Disorders / Q000139:chemically induced* / Q000188:drug therapy*; D051379:Mice; D021641:Recognition, Psychology / Q000187:drug effects* / Q000502:physiology; D018967:Risperidone / Q000008:administration & dosage*; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D015283:Citalopram; D016291:Dizocilpine Maleate; D018691:Excitatory Amino Acid Antagonists; D018967:Risperidone; D017367:Selective Serotonin Reuptake Inhibitors
keywords: Escitalopram; MK-801; Mice; Object recognition test; Risperidone