MnCl 2 -stimulated ERK and p38 MAPK activation in primary microglia. A and B . Microglia were stimulated with medium (0), or indicated concentrations MnCl 2 for 3 hr and the activation of ERK ( A ) or p38 MAPK ( B ) was determined by Western blotting for phospho-ERK or phospho-p38 MAPK. C and D . Cells were pretreated for 15 min with 25 µM U0126 (U, C ) or SB202190 (SB, D ) prior to treatment for 3 hr with 10 µM MnCl 2 . Top panels are representative Western blots of phospho-ERK (p-ERK) or p38 MAPK (p-p38) and corresponding total ERK (ERK) or total p38 MAPK (p38) obtained from one experiment. The bar graphs were intensities of the phospho-EKR or phospho-p38 MAPK bands expressed as a fold over that of the control cells and are mean ± SEM from three experiments. *, p