NMDAR-2C and 2D subunits gene expression is induced in brain by neonatal exposure of monosodium L-glutamate to adult rats.

Monosodium glutamate (MSG) was administered subcutaneously to male neonate rats, and the effects on N-methyl-D-asparatate (NMDA) subunit receptor types NR2C and NR2D from different brain regions were studied. A semi-quantitative reverse transcription-polymerase chain reaction was used to measure NR2C and NR2D expression levels in the cerebral cortex, hippocampus and striatum. MSG treatment (4 mg/g body weight, on postnatal days 1, 3, 5, and 7) produced an important increase of NR2C and NR2D subunit gene expression levels in the hippocampus and striatum of adults rats. No change was observed in the cerebral cortex. We propose that an early excessive activation of glutamate receptors could modify NMDA subunit expression and its structural composition on postnatal development. This, as part of a compensatory response by an altered neuronal circuitry, mainly in the hippocampus and striatum, suggests that the NMDA receptor could be a determinant factor to modulate the dendritic arrangement and the synaptogenesis.