Deficits in the expression of the NR2B subunit in the hippocampus of aged Fisher 344 rats

The NMDA receptor (NMDAR) has been implicated in the induction of LTP at hi ppocampal synapses, and has been proposed to play a significant role in thr involvement of the hippocampus with learning and memory. Aged rats are kno wn to have deficits in LTP, learning and memory. We tested the hypothesis t hat aged rats might have deficits in expression of NMDAR subunits. Aged rat s have significantly lower levels of NR2B mRNA and protein compared to youn g animals. This complements a recent report which showed improved learning and memory in mice which overexpress NR2B. No changes were seen in either t he mRNA or the protein levels of the NMDAR subunit NR2A, nor in the alpha - amino-3-hydroxy-5-methyl-4-isoxazole proprionate receptor (AMPAR) subunit G luR2. Our data support the hypothesis that age related alterations in the e xpression of the NMDAR NR2B subunit might underlie deficits in LTP and lear ning and memory in aged animals. (C) 2001 Elsevier Science Inc. All rights reserved.