Figure 4.

The absolute effect of (A) hydrochlorothiazide (HCTZ) and (B) bumetanide on fractional Na⁺ excretion (Δ FE_{N a( HCTZ )} and Δ FE_{N a(bumet)}, respectively) in P2X4^+/+ (■) and P2X4^−/− (□) mice on either a standard (n = 7 and 6 for HCTZ, 6 and 6 for bumetanide, respectively) or a low Na⁺ diet for 14 days (n = 7 and 6 for HCTZ, 6 and 6 for bumetanide, respectively). (C) Protein abundance of NCC and NKCC2 by Western blot analysis on a low Na⁺ diet. Analysis of signals was performed with an infrared‐based imaging system (n = 6 for all groups). Data are mean ± SEM, and comparisons were made with ANOVA using Bonferroni post‐hoc testing for (A) and (B), and t‐test for (C). *P < 0.05.