Effects of MAP kinase inhibitors and activators on NaChl-induced enhanced phosphorylation of p38 and ERK1/2 in K562 cells. Cells were pretreated with inhibitors or activators of MAP kinases for 30 minutes as described in “Materials and methods” before treatment with NaChl (10 μg/mL) for an additional 30 minutes. Filled histograms indicate staining with isotype-matched control mouse monoclonal antibodies. Solid lines indicate staining with anti–phospho p38 or anti–phospho ERK1/2 monoclonal antibody. Values within the histograms represent the specific MFI (after subtracting the respective control values).