Figure 1.
V2 receptors maintain maximal epithelial Na+ channel (ENaC) activity in Liddle mice. A: experimental scheme. After mice were fed a regular chow diet, ENaC activity was measured in freshly isolated and split-open distal nephrons. B: summary graphs comparing mean (±SE) total ENaC activity (NPo), number of channels (N), and open probability (Po) in cortical collecting ducts of wild-type (WT) littermates (n = 10) and Liddle mice (n = 14). Male mice are indicated by closed circles; female mice are indicated by open circles. *P < 0.05 by one-way ANOVA with Tukey’s correction between the indicated groups. C: summary graphs comparing means (±SE) NPo, N, and Po in cortical collecting ducts of WT littermates (n = 9) and pseudohypoaldosteronism type 1 (PHA1) mice (n = 12). Female mice are indicated by open circles. *P < 0.05 by one-way ANOVA with Tukey’s correction between the indicated groups. D: summary graphs of means (±SE) ENaC NPo, N, and Po in cortical collecting ducts of WT or Liddle mice under the following conditions: 1) baseline (WT: n = 10 and Liddle: n = 14), 2) tolvaptan (30 mg/kg) for 3 days (WT: n = 10 and Liddle: n = 14), 3) desmopressin (dDAVP) infusion (100 ng/h) for 4 days (WT: n = 10 and Liddle: n = 21), and 4) dDAVP + tolvaptan (WT: n = 8 and Liddle: n = 12). Male mice are indicated by closed circles; female mice are indicated by open circles. *P < 0.05 by one-way ANOVA with Tukey correction between the indicated groups.