The effects of NMDA receptors blockade during different critical developmental windows of the nervous system on the cognitive, emotional function activity at adult age in the BALB/c mice

Aim: In our study, we evaluated in the situation of NMDA receptor hypoactivity during critical developmental period, the effects of environmental enrichment on locomotor activity, emotional and cognitive functions of the brain at adult age.Materials and methods: For this aim, three ?developmental windows?, between 5-10. postnatal days as first window, 15-20. postnatal days as second window and 25-30. postnatal days as third window, were selected as a model. NMDA receptor hipofunction was performed during these devepomental windows by using MK-801 (for 5 days 0.25 mg / kg twice a day, intraperitoneal). In Balb/c mice treated with MK-801 and reared in physical standart and enrich environmental conditions, emotional behaviors were assessed by using open field, elevated plus maze and light-dark preference tests, and cognitive functions were assessed in the Morris water pool.Results: In the first development window (between 5-10. postnatal days), enrich environmental condition did not restorate deteriorating effects of MK-801 in locomotor activity, emotional and cognitive functions. In the second developmental window (between 15-20. postnatal day), MK-801 did not affect fear responses to open field, height and light and enrich environmental condition restorated MK-801-induced decreases in risk assessment behavior, spatial exploration and impairment in cognitive functions. In the third developmental window (between 25-30. postnatal days), enrich environmental condition restorated MK-801-induced decrease in risk assessment behavior but not cognitive functions.Conclusion: Physical environmental enrichment can restorate disturbance in emotional and cognitive functions dependent on the NMDA receptor hipofunction only during second developmental window. Practically, the physical environmental enrichment could restorate NMDA receptor system impairment at early childhood period.Keywords: Critical developmental period, MK-801, Balb/c mice, Physical environmental enrichment, Emotional and cognitive function.