Effect of the extracellular Ca2+ chelator EGTA, intracellular Ca2+ chelator BAPTA-AM, IP3R inhibitor Xestospongin C (Xesto C), cADPr inhibitor 8-Br-cADPr, and NAADP inhibitor Trans-Ned-19 (T Ned-19) on (A) CCh-induced mucus secretion and (B) GAP formation in the distal colon. (C–I) Representative images of the effect of the respective treatments on CCh-induced mucus secretion and GAP formation. Data are presented as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, n.s = non-significant as compared to CCh. Vehicle and CCh, n = 7, EGTA and 8-Br-cADPr n = 5, BAPTA-AM, Xesto C, and T-Ned-19 n = 6. Scale bar: C–I = 50 µm Statistical analysis was performed using a one-way ANOVA followed by Dunnet’s post hoc test. Each data point in (A–B) represents the average of 40 crypts from one mouse.