Fig. 4.

[Ca²⁺]_cyt in L2, R3/1, RLE, piAECs, and A549. a [Ca²⁺]_cyt under baseline conditions, b upon 100 μM ATP treatment in calcium-containing medium, c upon 100 μM ATP treatment in calcium-free medium, and d a comparison of [Ca²⁺]_cyt upon ATP (100 μM) stimulation in calcium-containing or calcium-free medium. Differences between the maximum and baseline [Ca²⁺]_cyt.(∆: delta) are displayed as box plots, with median values ± 75% and 25% quartiles, n = 6–31, * p < 0.001 vs. baseline conditions, ^§p < 0.001 vs. calcium-containing conditions