Glutamate but not interleukin-6 influences the phosphorylation of tau in primary rat hippocampal neurons

Alzheimer's disease (AD) is characterized by amyloid plaques, neuritic dege nerations, disturbed glutamatergic neurotransmission and a peculiar inflamm atory response. Diffuse plaques develop into neuritic plaques when neurites undergo degeneration in the plaque area. Hyperphosphorylation of tau prote ins is a major step in neuritic pathology. Interleukin-6 (IL-6) has been fo und in diffuse and neuritic amyloid plaques in AD. Therefore the question a rises whether IL-6 is involved in the transformation of diffuse into neurit ic plaques by affecting tau phosphorylation. We investigated the influence of glutamate and IL-6 on tau phosphorylation in cultured primary rat hippoc ampal neurons. Glutamate but not IL-6 induced a dephosphorylation of tau. F urthermore IL-6 did not influence the glutamate-induced dephoshorylation of tau. We conclude that the role of IL-6 in AD is not related to the phospho rylation of tau. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved .