Effect of plating density on ERK activation in 5-HT
R-CHO cells. Cells plated at the indicated densities for 24 hrs were preincubated overnight in serum-free medium, and stimulated with vehicle (Veh, open bars) or 1 μM 5-HT (gray bars) for 5 min. Levels of pERK were determined by plate immunoassay and normalized to cell number by crystal violet staining. Background (control wells without primary antibody) value was subtracted. Graph is representative of three independent experiments. n = 8; ** p < 0.01 vs. vehicle.