Figure 5: ATP-triggered Ca²⁺ signaling was not diminished by acidosis. [Ca²⁺]i was measured in bEND.3 cells in Ca²⁺-containing bath solutions of different pH. Cells were stimulated by 10 mM ATP. Results are mean ± SEM, each group having 29–39 cells from three to four separate experiments. SEM: Standard error of the mean.