Fig. 4. [Ca²⁺]i dynamics in ducts and acini measured at the individual cell level. (A) Fluorescence image. Cellular areas were selected from the acinus (yellow) and duct (green, orange, blue, red) and used for the quantitative measurement. (B) CCh in the absence of extracellular Ca²⁺. (C) CCh in the presence of extracellular Ca²⁺. (D) ATP in the absence of Ca²⁺. (E) ATP in the presence of extracellular Ca²⁺. Arrows denote the application time of each reagent.