Inhibition of Jak2 kinase blocked Akt phosphorylation and neuronal survival by IL-3. Primary cortical neurons were pre-treated with 20 μM AG490 for 30 min before addition of 5 nM IL-3. One hour after addition of growth factor, cells were exposed to 10 μM Aβ and incubated for an additional 24 h. Cells incubated with vehicle (PBS containing ≤ 0.1% DMSO v/v) and not exposed to IL-3 or Aβ were defined as control cells. Then the cells were used for Western blot and viability analysis. (A) Western blot analysis using phosphorylation-specific antibodies (p-Jak2, and p-Akt), and total anti-Akt1 and anti-Jak2 antibodies. (B). Normalized densitometry scans of proteins (mean ± SEM, *, #, p < 0.05). The student's t-test was used for the statistical analysis of significance of difference. (C). Neuronal death was determined by MTT colorimetric assay and Tripan blue exclusion. Data represent mean ± SEM for three independent experiments (with a minimum of 4–5 wells per group for each experiment).