Figure 5. The 1 μM FK506 (tacrolimus) treatment increases activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB). A: The 1 μM FK506 treatment for 30 min significantly activated NF-κB protein in 661w neuronal cell cultures. These were treated with 1 μM FK506 or the control (DMSO) for 30 min, 1 h, 2 h, or 4 h. Cell lysate proteins (25 ug) were separated by western immunoblot analysis for phosphor-NF-κB and β-tubulin. The quantification of band intensity is represented as the percentage of phospho NF-κB of the corresponding control (β-tubulin) band on the same membrane. B: The 1 μM FK506 significantly increased phospho NF-κB protein levels (p=0.004) at 30 min, while phospho NF-κB protein levels returned to near basal levels within 2 h of FK506 treatment (n=6). Error bars represent SEM.