Figure 1. Response of ACTOne ADRB2 cell line & parental cell line to Isoproterenol. ACTOne ADRB1 cells and parental cells (AG-10200-200) were plated overnight in 20 ml culture medium on a BD Biocoat 384 well plate. The next day, cells were dye-loaded with 20 ml/well of 1X Dye-loading solution (ACTOne Membrane Potential Assay Kit). After 2 hours of incubation at room temperature, two readings were obtained prior to and 30 min after the addition of the ligands. Ratios of the two readings (F/F0) are plotted in the figure. A. Dose response curves of Isoproterenol in ACTOne ADRB2 cell line. EC50 = 12.8 pM in the presence of 25 mM of PDE inhibitor Ro20-1724 and EC50 = 79.9 pM in the absence of PDE inhibitor Ro20-1724 B. EC50 of Isoproterenol is 12.39 nM in the parental cells in the presence of 25 mM of PDE inhibitor Ro20-1724. In the absence of PDE inhibitor, there is not much response to Isoproterenol in the parental cells