Abstract 383 Poster Session III, Monday, 5/3 (poster 153)

INTRODUCTION: Excitatory amino acid neurotransmitter receptors have been implicated in retinal damage. NMDA (N-methyl-D-aspartate) and AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) subtypes of glutamate receptors have been well characterized in the central nervous system. The overall goal of this study was to characterize the expression of NMDA and AMPA receptor subtypes in the developing mouse retina and to observe expression in a mouse model of oxygen induced retinopathy.

METHODS: C57BL6 mice were evaluated at postnatal days 0 through 17 for expression of NMDA and AMPA receptor subunits development in the retina. NR1, NR2A, NR2B, GluR1, GluR2/3, and GluR4 receptor subtypes were assessed by Western blot. Mice were exposed to 75% oxygen from postnatal day 7 through 12 and recovered in room air, which causes relative retinal hypoxia, to produce an oxygen induced retinopathy. In addition, samples of retinal tissue were obtained from mice with oxygen induced retinopathy at post natal days 12 and 17 to determine expression.

RESULTS: NR1, NR2A, NR2B, GluR1, GluR2/3, and GluR4 receptor subunits are all developmentally regulated with expression increasing two to three-fold over the first 17 days of life to adult levels. In addition, exposure of mice to oxygen causes a decrease in expression of all receptor subunits in the retina at postnatal days 12 and 17 when compared to control mice. Values are expressed as mean ± standard deviation. (Table)

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CONCLUSIONS: In summary, NR1, NR2A, NR2B, GluR1, GluR2/3, and GluR4 receptors subunits are developmentally regulated and are decreased by hyperoxic exposure and hypoxic recovery in the mouse retina. Modulation of receptor subunit expression may be an avenue to alter the development of retinopathy in the mouse.