Fig. 6. Etomidate activates mitogen-activated protein kinase phosphorylation via α^2B-receptors. (a ) ERK1/2 activation was detected in HEK293 cells expressing α^2B-receptors using phosphorylation-specific ERK1/2 antibodies (upper panel ) or conventional antisera to detect total ERK1/2 levels (lower panel ). Stimulation with 10 μm etomidate (ETO) for 20 min caused a significant increase in phospho-ERK1/2 levels in α^2B-receptor–transfected cells that was not observed in untransfected HEK293 cells (b ). Asterisk  indicates a significant difference (P < 0.05) with etomidate versus  control; n = 6 from three independent experiments. ERK1/2 = extracellular signal-related kinases.