A single high dose of dizocilpine produces long-lasting impairment of the water maze performance in adult rats.

The long-lasting effects of a single high dose treatment with the non-competitive N-methyl-D-aspartate (NMDA) antagonist dizocilpine (MK-801; 10 mg/kg, i.p.) on the water maze performance of rats were investigated. MK-801-treated rats learned to find the escape platform at a slower rate than control animals, and showed increased thigmotaxis during acquisition of the task. However, no differences were found between MK-801 and control groups on the probe trial, during repeated acquisition and on the visible platform task. These findings further support the idea that NMDA antagonists can be used in animal research to model persisting symptomatology of cognitive and psychotic disorders.