Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-14316
Rothenberger, F; Velic, A; Stehberger, P A; Kovacikova, J; Wagner, C A (2007). Angiotensin II stimulates vacuolar H+ -ATPase activity in renal acid-secretory intercalated cells from the outer medullary collecting duct. Journal of the American Society of Nephrology (JASN), 18(7):2085-2093.
Final urinary acidification is mediated by the action of vacuolar H(+)-ATPases expressed in acid-secretory type A intercalated cells (A-IC) in the collecting duct. Angiotensin II (AngII) has profound effects on renal acid-base transport in the proximal tubule, distal tubule, and collecting duct. This study investigated the effects on vacuolar H(+)-ATPase activity in A-IC in freshly isolated mouse outer medullary collecting ducts. AngII (10 nM) stimulated concanamycin-sensitive vacuolar H(+)-ATPase activity in A-IC in freshly isolated mouse outer medullary collecting ducts via AT(1) receptors, which were also detected immunohistochemically in A-IC. AngII increased intracellular Ca(2+) levels transiently. Chelation of intracellular Ca(2+) with BAPTA and depletion of endoplasmic reticulum Ca(2+) stores prevented the stimulatory effect on H(+)-ATPase activity. The effect of AngII on H(+)-ATPase activity was abolished by inhibitors of small G proteins and phospholipase C, by blockers of Ca(2+)-dependent and -independent isoforms of protein kinase C and extracellular signal-regulated kinase 1/2. Disruption of the microtubular network and cleavage of cellubrevin attenuated the stimulation. Finally, AngII failed to stimulate residual vacuolar H(+)-ATPase activity in A-IC from mice that were deficient for the B1 subunit of the vacuolar H(+)-ATPase. Thus, AngII presents a potent stimulus for vacuolar H(+)-ATPase activity in outer medullary collecting duct IC and requires trafficking of stimulatory proteins or vacuolar H(+)-ATPases. The B1 subunit is indispensable for the stimulation by AngII, and its importance for stimulation of vacuolar H(+)-ATPase activity may contribute to the inappropriate urinary acidification that is seen in patients who have distal renal tubular acidosis and mutations in this subunit.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > Center for Integrative Human Physiology|
04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
|DDC:||570 Life sciences; biology|
610 Medicine & health
|Deposited On:||20 Mar 2009 14:42|
|Last Modified:||23 Nov 2012 15:02|
|Publisher:||American Society of Nephrology|
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