Figure 3: Effect of ATP, UTP, and adenosine on CBF and intracellular Ca2+ levels in cultured ciliated cells. (a) time course response of CBF, expressed as a percentage (%) of baseline CBF, in response to stimulation with ATP 10 μM. After addition of ATP, CBF showed a rapid increase, followed by a plateau over the baseline CBF. After washing, the culture CBF returned to baseline. (b) Phase microscope image of ciliated cells in culture loaded with FURA-2AM. Showing 6 regions of interest (ROI) selected for calcium measurements with ATP stimulation. (c) ATP dose-response curve. Curve shows the logarithmic molar concentration of ATP and the area under the curve (AUC) for the CBF response observed for each concentration of ATP. Insert graph: average increase in CBF after exposure to UTP or adenosine (1 μM and 10 μM). (d) Time course response of intracellular calcium levels expressed as 340/380 fluorescence ratio after stimulation with ATP (10 μM). After adding ATP, a rapid increase in intracellular calcium is observed in all studied ciliated cells selected previously in ROI (c).