Figure 4
Expression of Ank-3 in principal cells is necessary for ENaC activity in the mouse collecting duct. (A) Representative gap-free current traces of ENaC in cell-attached recordings of the apical membranes of principal cells in micro-dissected collecting ducts from WT (top) and PC-specific Ank-3 KO mice (bottom): negative pipette potential -60 mV and inward Na+ current is downwards with closed states shown by dashed line. (B) Summary graph showing that ENaC activity (NPo) is significantly lower in PC-specific Ank-3 KO mice (white circles, white bar) versus WT mice (black circles, gray bar). Data from experiments (n = 12–16 patches from 3–4 distinct mice) identical to that shown in (A). *P < 0.05 vs. WT mice. (c) Representative current traces of ENaC in cell-attached patches made on the apical plasma membranes of principal cells in isolated tubules from WT (top) and PC-specific Ank-3 KO mice (bottom) pretreated for 30 min with 200 nM TBB. (D) Summary graph showing that ENaC activity is not different in tubules from WT (black circles, gray bar) versus PC-specific Ank-3 KO mice (white circles, white bar) pretreated with TBB. Data from experiments (n = 6–15 patches from 2–3 distinct mice) identical to that shown in (C).
