Resumen:
Alzheimer's disease (AD) is characterized phenotypically by memory impairment, histologically by accumulation of pTau and beta-amyloid peptide and morphologically by a loss of nerve terminals in cortical and hippocampal regions. As glutamate is the principle excitatory neurotransmitter of the central nervous system (CNS), the glutamatergic system may play an important role in AD. To date, not many studies have addressed the deleterious effects of A beta on glutamatergic terminals; therefore the aim of this study was to investigate how A beta affects glutamatergic terminals and to assess the extent to which alterations in the glutamatergic neurotransmission could impact susceptibility to the illness. The present study shows that A beta caused a loss of glutamatergic terminals, measured by VGLUT1 protein levels, in Tg2576 primary cell cultures, Tg2576 mice and AD patient brains, and also when A beta was added exogenously to hippocampal cell cultures. Interestingly, no correlation was found between cognition and decreased VGLUT1 levels. Moreover, when A beta(1-42) was intracerebroventricularlly administered into VGLUT1+/-mice, altered synaptic plasticity and increased neuroinflammation was observed in the hippocampus of those animals. In conclusion, the present study not only revealed susceptibility of glutamatergic nerve terminals to A beta induced toxicity but also underlined the importance of VGLUT1 in the progression of AD, as the decrease of this protein levels ...
