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. 1997 Apr 15;94(8):4086–4091. doi: 10.1073/pnas.94.8.4086

Figure 4.

Figure 4

Figure 4

The MEK inhibitor, PD 098059, blocks both NGF-mediated activation of MAPK and suppression of ROS formation. (A) MAPK activation in GT1-1 trk cells was determined by probing Western blots of cell lysates with a phospho-specific MAPK antibody (upper bands). The same blot was then stripped and reprobed with a control MAPK antibody that recognizes both phosphorylated and nonphosphorylated forms of ERK-1 and ERK-2 (lower bands). Lanes: 1, lysate from untreated GT1-1 trk cells (controls); 2, lysate from cells treated with 50 ng/ml NGF for 10 min; 3, lysate from cells pretreated for 30 min with 100 μM PD 098059, then with 50 ng/ml NGF for 10 min. (B) Fluorescence photomicrographs of SCG neurons treated with NGF and PD 098059. SCG neurons loaded with DHR, then deprived of NGF at t = 0, demonstrated a substantial increase in fluorescence 3 h after removal of NGF, whereas cells maintained in NGF showed little oxidation of the dye. PD 098059 (50 μM and 100 μM) coapplied with NGF reversed suppression of ROS by NGF in a dose-dependent fashion. Images are pseudocolor representations of fluorescence intensities, using arbitrary fluorescence intensity units on the linear color scale. (Bar = 50 μm.)