Effect of vasoactive intestinal peptide (VIP) on NFκB binding and IκB degradation in synovial cells from mice with collagen-induced arthritis (CIA). (a) EMSA results from nuclear extracts of synovial cells from CIA or VIP-treated CIA mice, using a radiolabeled oligonucleotide containing the NFκB consensus binding site. (b) Supershift assay on nuclear extracts of CIA mice using anti-p50, anti-p65 or anti-cRel. (c) Supershift assay (20-fold amplified) on nuclear extracts of VIP-treated CIA mice using anti-p50, anti-p65 or anti-cRel. (d) Western blot analysis showing immunoreactive IκBα (36 kDa) in cytoplasmic fractions of synovial cells from CIA and VIP-treated CIA mice. A representative experiment of three is shown.