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Angiotensin II activates H+‐ATPase in type A intercalated cells in mouse cortical collecting duct
Author(s) -
Pech Vladimir,
Zheng Wencui,
Pham Truyen D.,
Verlander Jill W.,
Wall Susan M.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1329-a
Subject(s) - chemistry , pendrin , intercalated cell , medicine , secretion , atpase , endocrinology , paracellular transport , transcellular , apical membrane , angiotensin ii , epithelial polarity , biophysics , membrane , biology , biochemistry , permeability (electromagnetism) , receptor , enzyme , transporter , gene
ANG II increases Cl − absorption in the mouse CCD by increasing transcellular transport across type B intercalated cells, through an H + ‐ATPase and Cl − /HCO 3 − exchanger (pendrin)‐dependent mechanism. Thus, we asked if ANG II induces subcellular redistribution of pendrin or the H + ‐ATPase, using quantitative immunogold cytochemistry of mouse CCDs perfused in vitro. ANG II (10 nM) application to the bath did not change the subcellular distribution of pendrin or the H + ‐ATPase in B cells, but increased apical plasma membrane H + ‐ATPase expression 3‐fold in A intercalated cells. To determine if ANG II increases H + ‐ATPase‐mediated H + secretion, J t‐CO2 was measured under identical conditions. Under basal conditions, HCO 3 − secretion was observed (J t‐CO2 = −4.2 ± 2.2 pmol/mm/min), while HCO 3 − absorption (J t‐CO2 = 2.5 ± 1.1 pmol/mm/min, P < 0.05) was observed with ANG II applied to the bath, consistent with apical H + ‐ATPase activation. Finally, application of the H + ‐ATPase inhibitor, bafilomycin, generated a more lumen‐negative transepithelial voltage, V T , in the presence, but not in the absence of ANG II. Conclusions: ANG II increases apical plasma membrane H + ‐ATPase expression and function. Increased H + secretion may increase NaCl absorption by: stimulating apical Cl − /HCO 3 − exchange by reducing luminal HCO 3 − concentration and increasing CO 2 formation and shunting V T generated by ENaC‐mediated Na + absorption.