DISTRIBUTION AND EXPRESSION OF THE SUBUNITS OF N-METHYL-D-ASPARTATE (NMDA) RECEPTORS - NR1, NR2A AND NR2B IN HYPOXIC NEWBORN PIGLET BRAINS

The purpose of this study was to identify the distribution and the exp ression of the NR1, NR2A and NR2B subunits of the NMDA receptor after cerebral hypoxia. Ten piglets were divided into control and hypoxic gr oups (n = 5, each). The control piglets were ventilated with normoxia for 1 h, and the hypoxic piglets were ventilated with hypoxia until p( a)O(2) was below 20 mmHg. Tissue samples from the nine different regio ns of newborn piglet brain were obtained, and the protein amount of th e NR1, NR2A, and NR2B subunits measured by immunoblot using the antibo dy to the NR1, NR2A, and NR2B subunits. The NR1, N2A, and NR2B subunit s were distributed very differently; hippocampus and cortical area are more prominent than white matter and cerebellum. But the expression o f the NR1, NR2A and NR2B subunits were not significantly different bet ween the control and the hypoxic group, 1 h after hypoxic exposure, in dicating no changes in the protein amount of NMDA receptor subunits. T hese results show a significantly higher amount of the NR1, NR2A and N R2B subunits in the hippocampus and the cerebral cortex of newborn bra ins, indicating that these structures could be highly vulnerable to ex citotoxicity in the newborn brain. (C) 1998 Elsevier Science B.V. All rights reserved.