| EXPRESSION OF NMDA RECEPTORS AND NEUROGENESIS IN THE
ADULT RAT HIPPOCAMPUS |
| B.S.McEwen1*; E.Varea2;
J.Nacher2 |
| 1. Lab Neuroendocrinol., The Rockefeller Univ., New York,
NY, USA |
| 2. Cell Biology and Neurobiology, The Univ. of Valencia,
Valencia, Spain |
|
The N-Methyl-D-aspartate (NMDA) glutamate receptor is
constituted in its functional form by two subunits: NR1 and NR2 (NR2A-D).
NMDA receptors play a crucial role in the regulation of neuronal development
and connectivity. These receptors are abundantly expressed in the
adult hippocampus, a region with continuous production and incorporation
of granule neurons. NMDA receptors appear to regulate the rate of
neurogenesis and proliferation in the adult hippocampus, although
the mechanism by which they influence these processes is not fully
understood. NMDA receptors seem to be functional in recently generated
granule cells, which are reported to display NR2B-dependent LTP. Despite
these relevant findings, there is no anatomical evidence on the expression
of NMDA receptors in young granule neurons during adulthood. We have
analyzed NR1 and NR2B expression in recently generated cells of the
adult rat dentate gyrus, using 5'BrdU labeling, GFP-retrovirus administration
and immunohistochemistry. Cells younger than 60 hours rarely express
NR1 or NR2B. By contrast, many cells generated 14 days before sacrifice
express both NMDA receptor subunits. We only have found very scarce
proliferating cells displaying clear NR1 or NR2 immunoreactivity.
Some of these cells may be astrocytes, because at least a subpopulation
of hippocampal GFAP immunoreactive cells expresses NR1 and NR2B.
Support Contributed By: MCYT BF12003-01254 and MH58911
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