JNK inhibitor suppressed the inhibitory effect of melittin and bee venom on the nuclear translocation of the p50 subunit and the release of IκB induced by LPS or SNP. Raw 264.7 cells (A) or synoviocytes (B) were pretreated with 10 and 20 μM SP600125 1 h prior to the treatment with melittin or bee venom with or without LPS (1 μg/ml) or SNP (200 μM) at 37°C for 24 hr. 80 μg of nuclear (p50 and p65), cytosolic IκB or total protein extracted after treatment were used to determine of p50, p65, p-IκBα, IκBα, or IκBβ; β-actin protein was used as an internal control. Each panel is representative of three similar experiments. C, Raw 264.7 cells were treated with LPS, BV and SP for 24 hr, and then the intracellular location of p50 was determined by immunofluorescence confocal scanning microscope (magnification, 630×). Double staining (Merge, pink) with p50 (red) and DAPI (blue) staining demonstrates the localization of p50 in the nucleus.