Figure. Concentration-dependent activation of VIPR2 by VIP. Reporter cells were transfected with either the expression plasmid for vaso­active in­tes­ti­nal pep­tide receptor 2 (VIPR2) or the mock plasmid and treated with various concentrations of vaso­active in­tes­ti­nal pep­tide (VIP). 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 13 nM.