ASIC1a contributes to ACh-induced Ca ²⁺ entry in mesenteric endothelial tubes. (A) Endothelial tubes were freshly isolated and loaded with fura-2. (B) Averaged traces showing Mn²⁺-quenching of fura-2 fluorescence at 360 nm excitation. Experiments were conducted under basal conditions or following ACh (10⁻⁶ M) in the absence or presence of PcTX1 (20 nM). (C) Summary data for percent quenched fura-2 fluorescence by Mn²⁺ at 5 min. Dotted line represents mean basal values. Data represent biological replicates and were analyzed by two-way ANOVA. The two-way ANOVA revealed that there was a statistically significant interaction (P = 0.0003) between factors. Post-hoc pairwise comparisons were analyzed between individual groups using Tukey’s multiple comparisons test.