The effect of NMDA antagonists on footshock-induced fighting behavior in chronically stressed rats

In the present study we investigated the effect of two non-competitive antagonists of N-methyl-D-aspartate (NMDA) subtype of glutamate receptor: memantine (2.5 mg/kg) or MK-801 (0.1 mg/kg) on electric footshock-induced fighting behavior in normal (unstressed) and chronically (14 various stressors over 16 days) stressed rats. In rats submitted to chronic stress the number of fighting attacks was reduced by about 60%. Prolonged treatment with memantine or MK-801 counteracted the deficit of aggression induced by chronic stress (the same effect was observed after a single dose of MK-801 but not of memantine). The findings of our study demonstrate, that the non-competitive NMDA antagonists can reduce the behavioral deficits produced by chronic stress, the effect of which is similar to those of antidepressant drugs.