Dual regulation of TNF-α on MLC phosphorylation. A and B: wild-type (WT) and IKK2−/− mouse aortic smooth muscle cells were treated with TNF-α (10 ng/ml) for 5 min, and MLC phosphorylation and IκBα expression were analyzed by Western blot; n = 3. *P < 0.05 vs. WT control; #P < 0.05 vs. IKK2−/− control, two-way ANOVA. C and D: aortic rings were prepared from C57Bl/6j mice and mounted onto myograph. After precontraction by phenylephrine (PE; 1 μM), TNF-α (10 ng/ml) was added. One representative recording (C) and the summary (D) of 4 independent experiments are presented. E and F: endothelium-denuded rat aortic rings were contracted by PE (1 μM), and then the indicated concentration of TNF-α was added in a cumulative manner. A representative recording (E) and the summary (F) from 3 independent experiments is present. G and H: aortic rings were prepared from smooth muscle specific IKK2 knockout (SM22-CreIKK2flox/flox) mice and mounted onto myograph. After precontraction by PE (1 μM), TNF-α (10 ng/ml) was added. One representative recording (C) and the summary (D) of 4 independent experiments are presented.