Figure 8.

Effects of N17-Ras expression and PMA pretreatment on dopamine-stimulated MAPK activity. CHO cells transfected in 6-cm dishes were serum starved for 18 h and stimulated with 100 nM DA for 5 or 20 min. (A) Cells were transfected with 1.4 μg of D₂R and 2.8 μg of either empty vector or N17-Ras. (B) Cells were transfected with 1.4 μg of D₂R and pretreated with PMA as described in the legend to Figure 5. Endogenous p42 MAPK activity was measured as described in the legend to Figure 1. Data are means ± SE of triplicate determinations. Similar results were obtained in at least one additional experiment.