[Ca2+]cyt in L2, R3/1, RLE, piAECs, and A549 upon stimulation with β-meATP, 2-meATP, and BzATP (100 μM). Displayed are differences between the maximum and baseline [Ca2+]cyt. (∆: delta) as box plots, with median values ± 75% and 25% quartiles, n = 3–20, * p < 0.001 vs. baseline conditions