RATIONALE: Chronic quinpirole (QNP) sensitization is an established animal model relevant to obsessive-compulsive disorder (OCD) that has been previously shown to induce several OCD-like behavioral patterns, such as compulsive-like checking and increased locomotion. OBJECTIVES: In current study we explored the effect of antiglutamatergic drugs, memantine and riluzole, on cognitive and behavioral performance of QNP sensitized rats. METHODS: During habituation phase, the rats (N = 56) were injected with QNP (0.25 mg/kg) or saline solution (every other day up to 10 injections) and placed into rotating arena without foot shocks for 50-min exploration. Active place avoidance task in rotating arena with unmarked to-be-avoided shock sector was used during acquisition phase. Rats were injected with memantine (1 mg/kg or 5 mg/kg), riluzole (1 mg/kg or 5 mg/kg) or saline solution 30 min before the trial and with QNP (0.25 mg/kg) or saline right before they were placed inside the rotating arena with 60° unmarked shock sector. Locomotion and number of entrances into the shock sector were recorded. RESULTS: QNP sensitization led to a robust deficit in place learning. However, neither memantine nor riluzole did reverse or alleviate the deficit induced by QNP. Contrarily, memantine significantly aggravated QNP induced deficit. CONCLUSIONS: The exacerbation of cognitive deficit following antiglutamatergic agents could be mediated by decreased glutamate concentration in nucleus accumbens and decreased hippocampal activation in the QNP sensitization model.

Institute of Physiology Czech Academy of Sciences Prague Czech Republic

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Memantine and Riluzole Exacerbate, Rather Than Ameliorate Behavioral Deficits Induced by 8-OH-DPAT Sensitization in a Spatial Task