POSTMORTEM CHANGES IN THE LEVELS AND LOCALIZATION OF MICROTUBULE-ASSOCIATED PROTEINS (TAU, MAP2 AND MAP1B) IN THE RAT AND HUMAN HIPPOCAMPUS

The neuronal cytoskeleton is disrupted in neurodegenerative disorders such as Alzheimer's disease. Due to the lack of suitable animal models , studies examining the events involved in the neurodegeneration have relied on postmortem human brain tissue obtained from individuals with the disease and from normal controls. However, it is uncertain if the neuronal cytoskeleton is stable during the postmortem interval. Immun ohistochemistry and immunoblots were used to examine the microtubule-a ssociated proteins tau, MAP2, and MAP1B in the rat hippocampus at vari ous times after death. Shortly after death, tau immunoreactivity was l ost from axons and accumulated in somatodendritic compartments. MAP2 a nd MAP1B also accumulated in neuronal cell bodies prior to a loss of i mmunostaining in some regions, notably subiculum. Immunoblots confirme d a loss of MAP2 and MAP1B within a few hours after death. Tau levels remained constant during the 8-hour postmortem interval examined, alth ough the electrophoretic mobility of some tau bands was altered. Human brain tissue obtained at autopsy and at surgery demonstrated similar cytoskeletal alterations in postmortem tissue. These results demonstra te that microtubules and associated proteins are not stable postmortem . (C) 1994 Wiley-Liss, Inc.