The collecting tubule of Amphiuma. II. Effects of potassium adaptation
Détails
ID Serval
serval:BIB_CA0F9843667D
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
The collecting tubule of Amphiuma. II. Effects of potassium adaptation
Périodique
American Journal of Physiology
ISSN
0002-9513 (Print)
Statut éditorial
Publié
Date de publication
12/1987
Volume
253
Numéro
6 Pt 2
Pages
F1273-82
Notes
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Dec
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Dec
Résumé
Electrophysiological and transport properties were studied in isolated and perfused Amphiuma collecting tubules from two groups of animals, one exposed to a high sodium (NA), the other to a high potassium (KA) environment (both conditions known to modulate blood aldosterone levels). The transepithelial lumen-negative potential was significantly larger (-38 +/- 5 mV) in tubules from KA animals than from NA animals (-15 +/- 3 mV). In addition, we observed an increase in the apical amiloride-sensitive sodium conductance and stimulation of the transepithelial sodium current. Although no measurable potassium conductance was found in the apical cell membrane in either group, a potassium selectivity of the paracellular transport pathway was observed in the KA animals. Net potassium secretion was demonstrated in KA tubules (helium-glow photometry and [3H]inulin analysis). Potassium secretion was abolished by luminal amiloride but imposition of a bath-to-lumen potassium gradient induced potassium secretion. We conclude that in contrast to the mammalian cortical collecting tubule in which potassium secretion is largely transcellular, potassium secretion in the Amphiuma collecting tubule is by diffusion through the paracellular pathway.
Mots-clé
*Adaptation, Physiological
Algorithms
Amiloride/pharmacology
Animals
Barium/pharmacology
Cell Membrane Permeability
Electrophysiology
Kidney Tubules/*physiology
Kidney Tubules, Collecting/*physiology
Membrane Potentials/drug effects
Potassium/*physiology
Reference Values
Urodela/*physiology
Pubmed
Web of science
Création de la notice
24/01/2008 12:38
Dernière modification de la notice
20/08/2019 15:45