Figure. Concentration-dependent activation of HTR2A by serotonin. Reporter cells were transfected with either the expression plasmid for 5-hy­droxy­tryp­ta­mine receptor 2A (HTR2A) or the mock plasmid and treated with various concentrations of serotonin. 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 1.9 nM.