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cAMP stimulates apical V-ATPase accumulation, microvillar elongation, and proton extrusion in kidney collecting duct A-intercalated cells.
- Source :
-
American journal of physiology. Renal physiology [Am J Physiol Renal Physiol] 2010 Mar; Vol. 298 (3), pp. F643-54. Date of Electronic Publication: 2010 Jan 06. - Publication Year :
- 2010
-
Abstract
- Kidney proton-secreting A-intercalated cells (A-IC) respond to systemic acidosis by accumulating the vacuolar ATPase (V-ATPase) in their apical membrane and by increasing the length and number of apical microvilli. We show here that the cell-permeant cAMP analog CPT-cAMP, infused in vivo, results in an almost twofold increase in apical V-ATPase accumulation in AE1-positive A-IC within 15 min and that these cells develop an extensive array of apical microvilli compared with controls. In contrast, no significant change in V-ATPase distribution could be detected by immunocytochemistry in B-intercalated cells at the acute time point examined. To show a direct effect of cAMP on A-IC, we prepared cell suspensions from the medulla of transgenic mice expressing EGFP in IC (driven by the B1-subunit promoter of the V-ATPase) and exposed them to cAMP analogs in vitro. Three-dimensional reconstructions of confocal images revealed that cAMP induced a time-dependent growth of apical microvilli, starting within minutes after addition. This effect was blocked by the PKA inhibitor myristoylated PKI. These morphological changes were paralleled by increased cAMP-mediated proton extrusion (pHi recovery) by A-IC in outer medullary collecting ducts measured using the ratiometric probe BCECF. These results, and our prior data showing that the bicarbonate-stimulated soluble adenylyl cyclase (sAC) is highly expressed in kidney intercalated cells, support the idea that cAMP generated either by sAC, or by activation of other signaling pathways, is part of the signal transduction mechanism involved in acid-base sensing and V-ATPase membrane trafficking in kidney intercalated cells.
- Subjects :
- 8-Bromo Cyclic Adenosine Monophosphate pharmacology
Adenylyl Cyclases metabolism
Animals
Bicarbonates metabolism
Cell Membrane Permeability
Cyclic AMP administration & dosage
Cyclic AMP metabolism
Cyclic AMP-Dependent Protein Kinases antagonists & inhibitors
Cyclic AMP-Dependent Protein Kinases metabolism
Fluorescent Antibody Technique
Hydrogen-Ion Concentration
Immunohistochemistry
Infusions, Intravenous
Kidney Tubules, Collecting drug effects
Kidney Tubules, Collecting ultrastructure
Male
Mice
Mice, Transgenic
Microscopy, Confocal
Microscopy, Fluorescence
Microvilli enzymology
Promoter Regions, Genetic
Protein Kinase Inhibitors pharmacology
Protein Transport
Rats
Rats, Sprague-Dawley
Signal Transduction
Thionucleotides administration & dosage
Time Factors
Vacuolar Proton-Translocating ATPases genetics
Acid-Base Equilibrium
Cyclic AMP analogs & derivatives
Kidney Tubules, Collecting enzymology
Thionucleotides metabolism
Vacuolar Proton-Translocating ATPases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1522-1466
- Volume :
- 298
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Renal physiology
- Publication Type :
- Academic Journal
- Accession number :
- 20053793
- Full Text :
- https://doi.org/10.1152/ajprenal.00584.2009