Figure 7. Effect of elevated cAMP on p38 MAP kinase activation. p38 MAP kinase activation following exposure to 20 ng/ml TNF-α (T) for 10 min with or without pre-treatment with 10 µM forskolin (F) and 50 µM rolipram (R) for 30 min was confirmed by immunoblotting using both anti-phospho-specific p38 MAP kinase antibody and anti-p38 MAP kinase antibody. A: TNF-α-induced phosphorylation of p38 MAP kinase following 10 min of exposure. However, pre-treatment with forskolin (F) and rolipram (R) suppressed p38 MAP kinase phosphorylation induced by TNF-α (T). B: Bar graph of the densitometric analysis of three independent experiments similar to that shown in A. The ratio of phosphorylated to total p38 MAP kinase following TNF-α stimulation is significantly increased when compared to untreated cells. Pre-treatment with F and R followed by stimulation with TNF-α significantly decreases the ratio. * and ** denotes p<0.001 when comparing the TNF-α-treated group with the control group and the (TNF-α+F+R)-treated group with the TNF-α-treated group, respectively.