Figure 1. Pharmacological characterization of transepithelial transport of Na⁺, K⁺, and Cl^– in collecting ducts isolated from wild-type mice.

(A) Effects of amiloride (10^–5 M) and HCTZ (10^–4 M) on Na⁺, Cl^–, and K⁺ transepithelial fluxes and on transepithelial voltage in CCDs isolated from Na⁺-restricted mice. J_Na, rate of Na⁺ absorption; J_Cl, rate of Cl^– absorption; V_te, transepithelial voltage; J_K, rate of K⁺ secretion. Statistical significance was assessed by ANOVA; comparisons between groups were tested by Bonferroni’s post-hoc test. n = 5 in each group, *P < 0.05 versus control, ^#P < 0.05 versus low Na⁺; ^†P < 0.05 versus low Na⁺ amiloride (amil). (B) Effects of HCTZ alone (10^–4 M) on Na⁺, Cl^–, and K⁺ transepithelial fluxes and on transepithelial voltage in CCDs isolated from Na⁺-restricted mice. Statistical significance was assessed by 2-tailed unpaired Student’s t test. n = 5 in each group; *P < 0.05 versus control (low Na).