Figure 2.

Deletion of neural precursor cell expressed developmentally downregulated protein 4-2 (Nedd4-2) eliminates the effect of dietary Na⁺ intake on the basolateral K⁺ conductance in the distal convoluted tubule (DCT). A: set of traces showing Ba²⁺-sensitive K⁺ currents measured with a step protocol from −60 to 60 mV in the DCT of wild-type [WT; floxed neural precursor cell expressed developmentally downregulated gene 4-like (Nedd4l^fl/fl)] mice and kidney-specific Nedd4-2 knockout (Ks-Nedd4-2 KO) mice on normal-salt (NS), high-salt (HS), and low-salt (LS) diets for 14 days, respectively. B: traces showing Ba²⁺-sensitive K⁺ currents measured with a ramp protocol (from −100 to 100 mV) in Ks-Nedd4-2 KO mice on NS, HS, and LS diets for 14 days, respectively. (A trace from a control mouse on NS is included as a reference.) The DCT was bathed in 140 mM KCl-containing solution, and the pipette solution also contained 140 mM KCl. C: scatterplot summarizing K⁺ currents measured at –60 mV in the DCT of male and female WT and KS-Nedd4-2 KO mice on HS for 7 days (HS-7d), HS for 14 days (HS-14d), NS, and LS for 14 days (LS-14d). Mean values and SEs are shown on the left of each column. Significance was determined by two-way ANOVA.