Figure. Concentration-dependent activation of ADRA2B by nor­adrenal­ine. Reporter cells were transfected with either the expression plasmid for adreno­ceptor alpha 2B (ADRA2B) or the mock plasmid and treated with various concentrations of nor­adrenal­ine. Data points shown are the mean ± SEM of an experiment performed in triplicate, and the curve is a fit to Hill equation with an EC50 of 33 nM.