Rapid Reversible Phosphorylation of Rat Brain Tau Proteins in Response to Cold Water Stress

The effect of cold water stress (CWS) on the phosphorylation of tau proteins in rat brain was studied using monoclonal antibodies to phosphorylated (PHF-1) and non-phosphorylated (TAU-1) epitopes. CWS induced an immediate 2-3-fold increase of PHF-1 signal in the soluble fraction of rat brain cortex, hippocampus and cerebellum. A maximal 3-4-fold increase occurred in 30-90 min. The soluble TAU-1 signal decreased following the CWS and at 60 min became significantly lower (P < 0.05) than in the control. Both signals returned to the normal range within 3 h. CWS induced a similar increase in PHF-1 signal in adrenalectomized animals and in animals subchronically treated with cortisone. These data indicate that stress induces rapid phosphorylation of soluble rat brain tau without direct involvement of the hypothalamic-pituitary-adrenal axis.