Localization of non-N-methyl-D-aspartate glutamate receptors in normal and Alzheimer hippocampal formation.

The hippocampi and adjacent temporal cortices of 24 human brains were examined with antibodies to the GluR1, GluR2/3, and GluR4 subunits of the D,L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-preferring glutamate receptor. GluR1 immunoreactivity was most dense in the dentate gyrus, with lower densities in other hippocampal and cortical regions. GluR2/3 immunoreactivity was the most intense of the three antibodies, with high levels throughout most hippocampal subfields, where it was localized to cell bodies, proximal axons, and dendrites. GluR4 immunoreactivity was very sparse in all regions. In Alzheimer's disease brains, the general pattern of staining was similar to that seen in control brains. GluR1 and GluR4 immunoreactivity was seen in some but not all neuritic plaques. All three antibodies recognized some neurons undergoing neurofibrillary degeneration.