Figure 7

ERK phosphorylation by DSLET (filled squares) or EGF (open triangles) in C6 glioma cells stably-expressing the δ-OR. C6-δ-OR cells were serum-starved overnight prior to exposure to EGF (0.1 nM – 1 μM for 5 minutes) or DSLET (0.1 nM – 1 μM for 5 minutes). In some instances, DSLET-mediated ERK phosphorylation was performed in cells pre-treated with AG1478 (1 μM; filled circles) 60 minutes prior to DSLET. After agonist exposure, cell lysates were prepared and ERK phosphorylation was determined by SDS PAGE, followed by immunoblotting of proteins onto nitrocellulose. PhosphoERK -immunopositive bands were quantified using the MCID system. Band intensities are expressed graphically as: grain density × band area - [region of detection (ROD)] × pixel. Data points represent the mean ± SEM of three experiments.