Figure 2. Dose–response relations in wild-type prestin-transfected TSA cells.
The three parameters of curve fitting of NLC functions are charge density (A), α (B) and V1/2 (C). DBcGMP application alone (•) and DBcGMP application in the presence of 100 μm 8-Rp-pCPT-cGMPS (□) are shown separately. At any concentration, data are presented as percentage of the appropriate set of control data and normalized to maximum response (±s.d., shown as percentage of the control s.d.). Experimental and control data were obtained from same-day transfection batches. Systematic effects due to DBcGMP application occur only for the charge density parameter. Results for DBcGMP application are fitted with the Hill equation: cn/(cn+Kdn). Where c is the concentration and n is the Hill coefficient. Least-square fit values are: n = 8.4 and Kd = 180 μm. Data for the combined 8-Rp-pCPT-cGMPS–DBcGMP application are also shown normalized for the daily control. A modified form of the Hill equation, having asymptotes at −1 and +1, is used to fit the data. Parameters of the least-square fit: n = 2, Kd = 401.