Figure. Concentration-dependent activation of CHRM4 by carbachol. Reporter cells were transfected with the expression plasmid for cholin­ergic receptor mus­ca­rinic 4 (CHRM4) and treated with various concentrations of carbachol. 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 47 nM.