Fig. 1.

IL-1β induces a rapid and transient phosphorylation of ERK1/2 and p38 MAPK in rabbit colonic smooth muscle cells (SMCs). Cultured and serum-starved (left; duplicate) or freshly isolated (right) SMCs were treated with IL-1β (10 ng/ml) for indicated time periods followed by Western blot analysis with anti-phosphorylated (p-)ERK1/2 (A) or anti-p-p38 (B) antibodies. Expression levels of total ERK1/2 (A) or p38 (B) were used as internal controls. The number under each blot indicates the relative fold of optical density compared with the corresponding control.