Figure 1: Extracellular acidity did not affect basal cytosolic Ca²⁺ level but suppressed CaSR-triggered Ca²⁺ signaling. [Ca²⁺]i was measured in bEND.3 cells bathed in Ca²⁺-containing solution. Cells were exposed to extracellular acidity (a). Cells bathed in Ca²⁺-containing solution of different pH were stimulated by (b) 3 mM Ca²⁺, significant (P < 0.05) differences between the pH 7.4 group and the pH 6.8 and 6.0 groups began after 171 and 116 s, respectively; (c) 3 mM spermine, significant (P < 0.05) differences between the pH 7.4 group and the pH 6.8 and 6.0 groups began after 132 s, or (d) 10 mM cinacalcet, significant (P < 0.05) differences between the pH 7.4 group and the pH 6.8 and 6.0 groups began after 233 and 132 s, respectively. Results are mean ± SEM, each group had 22-28 cells obtained from three to four separate experiments. SEM: Standard error of the mean.