Figure 1. Response of ACTOne ADRB1 cell line & parental cell line to Norepinephrine and 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 curve of Norepinephrine or Isoproterenol in ACTOne ADRB1 cell line. With Norepinephrine, EC50 = 243 pM in the presence of 25 mM of PDE inhibitor Ro20-1724; With Isoproterenol, EC50 = 43.8 pM in the presence of 25 mM of PDE inhibitor Ro20-1724 B. Parental cells do not respond to Norepinephrine. The Parental cells do not respond to Isoproterenol when it is lower than 1 nM.