Glutamate increases tau phosphorylation in primary neuronal cultures from fetal rat cerebral cortex.

Tau proteins are microtubule-associated proteins which promote microtubule polymerisation and stabilization. AT8 is a new monoclonal antibody raised against a phosphorylated Tau protein probably at Serine 202. Tau protein, recognized by AT8 antibody is present in fetal human and rat brains, and in Alzheimer's brains. Here we report that glutamate an excitatory neurotransmitter and also a potent excitotoxin produces in primary neuronal cultures a rapid increase in phosphorylated Tau protein immunoreactivity using AT8 antibody. Glutamate augments neuronal Tau immunoreactivity by 225% using laser confocal immunocytochemistry and by 355% on immunoblot analysis. This experimental model of Tau protein modifications could help to decipher the intracellular biochemical pathways at the origin of phosphorylated Tau protein.