DISTRIBUTION OF AMPA RECEPTOR SUBUNITS IN THE NUCLEUS BASALIS OF MEYNERT IN AGED HUMANS - IMPLICATIONS FOR SELECTIVE NEURONAL DEGENERATION

Immunocytochemical techniques using polyclonal antibodies directed aga inst GluR1 and GluR2/3 subunits of the AMPA-selective receptor complex were used to examine the distribution of these receptor subunits with in the nucleus basalis of Meynert (NBM) of non-demented elderly humans . Both somata and processes of magnocellular neurons within the NBM we re intensely immunoreactive to GluR1 antibodies. In contrast, within t he same region GluR2/3 immunolabeling was largely absent, although Glu R2/3-positive neurons were abundantly distributed within adjacent brai n regions (i.e., amygdala, entorhinal cortex and hippocampus). These d ata suggest that NBM neurons may be unique, compared to those of other brain regions, in their response to glutamatergic excitation as media ted via non-NMDA receptors and be particularly vulnerable to glutamate excitotoxicity via a mechanism involving the destabilization of intra cellular calcium.