The Effect of N-Methyl-D-Aspartate (NMDA) Receptor Blockade and Physical Environmental Enrichment During Childhood on Emotional and Cognitive Function in Adulthood in Balb/C Mice

Objective: The NMDA receptor-mediated glutamate system plays an important role in brain development and maturation in the period of early development. Physically-enriched environments positively influence cognitive performance and produce neuroanatomical changes in the brain. Material and Method: In our study, we evaluated the effects of NMDA receptor hypoactivity and physical environmental enrichment during childhood on emotional and cognitive functions in adult Balb/c mice. NMDA receptor hypofunction was induced during this developmental period using MK-801 (for 5 days, 0.25 mg/kg twice a day, intraperitoneal). Balb/c were mice treated with MK-801 and reared in standard or environmentally enriched conditions, then emotional behaviours were assessed using the open field (OF) and elevated plus maze (EPM), and cognitive functions were assessed using the Morris water maze (MWM). Results: MK-801 administration decreased anxiety-related behaviours in the OF (p<0.05). MK-801 decreased risk assessment behaviour in the EPM (p<0.05). An enriched environment restored the MK-801-induced decrease in risk assessment behaviour (p<0.05) but not cognitive functions. An enriched environment did not restore the deteriorating effects of MK-801 on cognitive function in the MWM (p>0.05). Conclusion: In this developmental period, physical environmental enrichment can restore disturbances in emotional behaviours dependent on NMDA receptor hypofunction, but not cognitive function.