A p38 MAPK inhibitor, SB203580, attenuates TGF-β1-impaired forskolin response. A: typical responses to forskolin (2 μM) in PVD9902 monolayers exposed to vehicle, TGF-β1 (5 ng/ml), SB203580 (10 μM), or TGF-β1 plus SB203580. B: responses to forskolin are summarized from 4–5 experiments. *P < 0.05, statistical significance.