Phosphorylated tau/total tau ratios were expressed as percentage of wild-type Sham values. Differences were detected by one-way ANOVA followed by Tamhane test. A) A significant increase in tau phoshporylation was observed in the cortex after serotonergic denervation [F(3,20) = 6.557, **p = 0.03 vs. sham wildtype and 5,7-DHT wildtype, ††p = 0.03 vs. sham wildtype]. B) We observed an increase in tau phosphorylation in the hippocampus of APPswe/PS1dE9 mice treated with 5,7-DHT however differences did not reach statistical significance [F(3, 19) = 1.938, p = 0.158]. C) Illustrative example of western blot for phospho-tau, total tau and actin, including cortex and hippocampus from sham wildtype, 5,7-DHT wildtype, sham APPswe/PS1dE9 and 5,7-DHT APPswe/PS1dE9 mice. An increase in phospho-tau can be observed in lesioned transgenic mice.