PLASMA-MEMBRANE FRAGILITY IN DYSTROPHIC NEURITES IN SENILE PLAQUES OFALZHEIMERS-DISEASE - AN INDEX OF OXIDATIVE STRESS

This study presents evidence for plasma membrane abnormalities of the dystrophic neurites in senile plaques of Alzheimer's disease. We found that the plasma membranes of dystrophic neurites are more labile to f ixation than those membranes of other cells of the senile plaque or of normal neurites distant from senile plaques. Further, we found vesicl es in the extracellular space adjacent to dystrophic neurites and simi lar to those within them, suggesting that the increased lability seen in our preparations may, in vivo, be associated with release of neurit ic contents. Plasma membrane alterations may be critical to deposition of amyloid-beta in senile plaques from the abundant beta-protein prec ursor of dystrophic neurites. The consequences of altered membrane int egrity, such as calcium influx, lipid peroxidation and free radical da mage, could also be responsible for many of the pathological correlate s of the disease.