Effects of α,β-dehydrolovastatin (DHLV) on Ca²⁺-activated Cl^- channels (CaCC), the intracellular Ca²⁺ levels induced by ATP and Na⁺/K⁺ ATPases activity.

(A, left) Representative apical I_Cl^- tracing showing the effect of ATP (100 μM) activation after 15 min pre-treatment with CFTR_inh-172 (5 μM) with vehicle (control) or DHLV (20 μM). (A, right) Summary of the data of peak I_Cl^- expressed as mean of peak I_Cl^- ± S.E.M. (n = 5). * p < 0.05 compared with control. Intracellular Ca²⁺ levels were analyzed from the fluo-8-based fluorescence assays. Fluo-8 fluorescence intensity were measured following vehicle (control) or DHLV (20 μM) together with the addition of ATP (100 μM) and end up with EGTA (3 mM). (B) Representative values of the fractional change in fluorescence intensity relative to baseline (ΔF/F⁰) are shown. (C) Summary of total AUC values after baseline correction presented as the area under the curve (AUC) ± S.E.M (n = 4). NS, non-significant (Student’s t test). (D, left) Ouabain-sensitive I_SC tracing showing the effect of DHLV on Na⁺-K⁺ ATPase activity. After T84 cells were permeabilized at apical membrane, ouabain (1 mM) was added. (D, right) Summary of the data are expressed as mean of ouabain-sensitive I_SC ± S.E.M. (n = 4). NS, non-significant (Student’s t test).