The effect of neonatal N-methyl-D-aspartate receptor blockade on exploratory and anxiety-like behaviors in adult BALB/c and C57BL/6 mice

Abstract

N-methyl-D-aspartate (NMDA) receptors play an important role in brain maturation and developmental processes. In our study, we evaluated the effects of neonatal NMDA receptor blockade on exploratory locomotion and anxiety-like behaviors of adult BALB/c and C57BL/6 mice. In this study, NMDA receptor hypofunction was induced 7-10 days after birth using MK-801 in BALB/c and C57BL/6 mice (0.25 mg/kg twice a day for 4 days via intraperitoneal injection). The open-field (OF) and elevated plus maze (EPM) tests were used to evaluate exploratory locomotion and anxiety-like behaviors. In the OF. BALB/c mice spent less time in the center of the field (p < 0.05) and had less vertical locomotor activity (p < 0.01) compared to C578L/6 mice. In BALB/c mice, MK-801 caused a decrease in vertical and horizontal locomotor activity in the OF test, compared to the control group (p < 0.05). In C57BL/6 mice, MK-801 treatment increased horizontal locomotor activity and decreased time spent in the center in the OF test (p < 0.05). In the EPM, the number of open-arm entries, the percentage of open-arm time (p < 0.01) and total arm entries (p < 0.05) were lower in BALB/c mice compared to C57BL/6 mice. In BALB/c mice, MK-801 caused an increase in the percentage of open-arm time compared to the control group (p < 0.05). In C57BL/6 mice, MK-801 caused a decrease in the percentage of open-arm time compared to the control group (p < 0.05). MK-801 decreased exploratory and anxiety-like behaviors in BALB/c mice. In contrast, MK-801 increased exploratory and anxiety-like behaviors in C57BL/6 mice. In conclusion, hereditary factors may play an important role in neonatal NMDA receptor blockade-induced responses. (C) 2012 Elsevier B.V. All rights reserved.