Effects of acute administration of MK-801, a non-competitive antagonist of NMDA receptors, on active avoidance in mice.

MK-801 is a dibenzocycloheptenimine with non-competitive antagonism of the N-methyl-D-aspartate (NMDA) receptor, In this experiment the effects of MK-801 (0.3, 0.1, 0.003 and 0.001 mg/kg) on active avoidance were studied in Balb/c/JIco mice. The experimental session consisted of 60 trials in which a white light (10 sec) was used as conditioned stimulus and a weak electric shock (0.28 mA) as unconditioned stimulus(10 sec). Results showed that response latency was significantly lower in groups treated with 0.1 and 0.3 mg/kg. The number of avoidance responses decreased only in the group treated with 0.3 mg/kg., although this dose also induced stereotypies and hyperactivity. We suggest that the doses ranging between 0.1 and 0.3 seem to be the most appropriate in this behavioral model.