Evaluating Effects of Visual Deprivation during Critical Period of Brain Development on Expression of NMDA Receptor Subunits in Rat's Hippocampus

Background and Visual deprivation during critical period of brain development impairs structure and function of NMDA receptors in visual cortex. Parts of visual signals go to the hippocampus through the visual cortex. Therefore, this study aimed at investigating the effects of visual deprivation during critical period of brain development on NMDA receptor subunits expression in rats’ hippocampus. This experimental study was carried out in 36 male rats that were divided into two groups. They were kept in standard 12 hour light/dark condition (Light Reared-LR) or in complete darkness (Dark Reared-DR) from birth to the time of experiments. The animals in each group were divided into 3 groups and studied at the ages of 2, 4 and 6 weeks. Expression of mRNA of NR1, NR2A and NR2B subunits in hippocampus was evaluated by RT-PCR using Western Blot technique. The protein expression of those subunits was also investigated. Relative expression of mRNA and protein of NR1 and NR2A subunits increased time dependently in LR animals, but the expression of NR2B subunit did not change. Although dark rearing did not prevent increasing of NR1 expression, but reduced the expression of NR2A and NR2B subunits. Visual deprivation during critical period of brain development time dependently inhibited maturation of NMDA receptor of rat’s hippocampus.