BDNF and Alzheimer disease: To observe the effects of BDNF (both 0.25 and 1.0 μg/side have the same behavioral effects; therefore, rats in the 0.25 μg/side group were chosen for further analysis), NGF (0.25 μg/side) and NT-3 (0.25 μg/side) on MAPK activation in the Aβ1-42-treated rat model of Alzheimer's disease, we analyzed the expression of total ERK, JNK and p38, as well as their phosphorylated (activated) forms, in the hippocampus after treatment (Fig 3).