Granulocyte macrophage-colony stimulating factor (GM-CSF) enhances lipolysaccharide (LPS)-induced nuclear factor (NF)-κB nuclear translocation. After pretreating with GM-CSF or leaving untreated for 48 h, microglia were harvested, washed twice, and seeded at a density of 1 × 107 cells/well. Then the cells were treated with LPS (1 μg/ml) for varying times (0 to 30 minutes). Nuclear fractions from the cells were separated and the levels of NF-kB/p65 in the nuclear fractions were assessed by ELISA. Data are representative of three independent experiments. ***P < 0.001 (GM-CSF-pretreated vs. -untreated).