Versatility of NaCl transport mechanisms in the cortical collecting duct
Files
Accepted manuscript
Date
2017-12-01
Authors
Edwards, Aurelie
Crambert, Gilles
Version
Accepted manuscript
OA Version
Citation
Aurelie Edwards, Gilles Crambert. 2017. "Versatility of NaCl transport mechanisms in the cortical collecting duct." AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY, Volume 313, Issue 6, pp. F1254 - F1263 (10). https://doi.org/10.1152/ajprenal.00369.2017
Abstract
Versatility of NaCl transport mechanisms in the
cortical collecting duct. Am J Physiol Renal Physiol 313: F1254 –F1263, 2017. First
published September 6, 2017; doi:10.1152/ajprenal.00369.2017.—The cortical collecting duct (CCD) forms part of the aldosterone-sensitive distal nephron and plays
an essential role in maintaining the NaCl balance and acid-base status. The CCD
epithelium comprises principal cells as well as different types of intercalated cells.
Until recently, transcellular Na transport was thought to be restricted to principal
cells, whereas (acid-secreting) type A and (bicarbonate-secreting) type B intercalated cells were associated with the regulation of acid-base homeostasis. This
review describes how this traditional view has been upended by several discoveries
in the past decade. A series of studies has shown that type B intercalated cells can
mediate electroneutral NaCl reabsorption by a mechanism involving Na-dependent and Na-independent Cl/HCO3
exchange, and that is energetically driven by
basolateral vacuolar H-ATPase pumps. Other research indicates that type A
intercalated cells can mediate NaCl secretion, through a bumetanide-sensitive
pathway that is energized by apical H,K-ATPase type 2 pumps operating as
Na/K exchangers. We also review recent findings on the contribution of the
paracellular route to NaCl transport in the CCD. Last, we describe cross-talk
processes, by which one CCD cell type impacts Na/Cl transport in another cell
type. The mechanisms that have been identified to date demonstrate clearly the
interdependence of NaCl and acid-base transport systems in the CCD. They also
highlight the remarkable versatility of this nephron segment.