Na+/H+exchangers in the human eccrine sweat duct
Open Access
- 1 November 2003
- journal article
- Published by American Physiological Society in American Journal of Physiology-Cell Physiology
- Vol. 285 (5), C1047-C1058
- https://doi.org/10.1152/ajpcell.00581.2002
Abstract
Using an anti-NHE1 antibody, we demonstrate the presence of a Na+/H+ exchanger of isoform 1 (NHE1) in the human eccrine sweat duct. A strong staining was observed at the basolateral membrane of the outer cell layer (NHE1basal), at the junction between inner and outer cells layers (NHE1inter), and along the lateral membranes (NHE1later) of all cells of the duct. At the luminal membrane, no staining was demonstrated either for NHE1 or NHE3. To investigate Na+/H+ mediated proton transport, straight sweat duct portions were isolated and perfused in vitro under HCO3--free conditions. In the presence of basolateral 5-ethyl- N -isopropyl amiloride (EIPA), an acidification of 0.29 ± 0.03 pH units was observed, whereas no effect was observed with luminal EIPA. Bath sodium removal generated a stronger acidification (0.41 ± 0.09 pH units). Removal of luminal sodium (in the absence or presence of basolateral EIPA), or low luminal chloride, led to an alkalinization, presumably due to a decrease in intracellular sodium, strongly suggesting functional activity of NHE1inter. We therefore conclude that in the sweat duct, NHE1 plays a major role in intracellular pH regulation.Keywords
This publication has 53 references indexed in Scilit:
- Expression of NHE-3 in the apical membrane of rat renal proximal tubule and thick ascending limbKidney International, 1995
- Intracellular potassium activity and the role of potassium in transepithelial salt transport in the human reabsorptive sweat ductThe Journal of Membrane Biology, 1991
- Basolateral membrane Na+/H+ antiport, Na+/base cotransport, and Na+-independent Cl-/base exchange in the rabbit S3 proximal tubule.JCI Insight, 1989
- Molecular cloning, primary structure, and expression of the human growth factor-activatable antiporterCell, 1989
- Intracellular pH regulation in the S3 segment of the rabbit proximal tubule in HCO3- -free solutions.The Journal of general physiology, 1988
- Higher Bioelectric Potentials Due to Decreased Chloride Absorption in the Sweat Glands of Patients with Cystic FibrosisNew England Journal of Medicine, 1983
- Structure of the tight junctions of the human eccrine sweat glandJournal of Anatomy, 1981
- Intracellular pH measurements in Ehrlich ascites tumor cells utilizing spectroscopic probes generated in situBiochemistry, 1979
- Localization of Na/K-ATPase sites in the secretory and reabsorptive epithelia of perfused eccrine sweat glands: A question to the role of the enzyme in secretionThe Journal of Membrane Biology, 1976
- Models for coupling of salt and water transport; Proximal tubular reabsorption in Necturus kidney.The Journal of general physiology, 1975