C Plot shows results of GPCR screen as ratio of cell toxicity and viability. Domperidone and TCAs highlighted in red and orange, vehicle controls in green and positive toxicity controls in blue. Z′ factor was calculated according to the formula Z′ = 1 - (3(θp +θn)/(μp - μn)), where p is the positive control, n is the negative control, θ is the standard deviation, and μ is the mean. For hit selection a threshold of lower than 3 standard deviations from the median of the negative/ vehicle population was set. 