The Shaker B K(+) conductance (G(K)) collapses (in a reversible manner) if the membrane is depolarized and then repolarized in, 0 K(+), Na(+)-containing solutions (Gómez-Lagunas, F. 1997. J. Physiol. 499:3-15; Gómez-Lagunas, F. 1999. Biophys. J. 77:2988-2998). In this work, the role of Na(+) ions in the collapse of G(K) in 0-K(+) solutions, and in the behavior of the channels in low K(+) was st...

objective: changes in chloride cell abundance, na+, k+-atpase immunolocalization and activity were investigated in the gills of the golden grey mullet, liza aurata, fry acclimated to freshwater (fw) and different salinities (12‰, 36‰ and 46‰). materials and methods: na+, k+-atpase localization was performed through immunofluorescence light microscopy using a mouse monoclonal antibody iggα5. qua...

The roles of Ser775 and Glu779, two amino acids in the putative fifth transmembrane segment of the Na,K-ATPase alpha subunit, in determining the voltage and extracellular K+ (K+(o)) dependence of enzyme-mediated ion transport, were examined in this study. HeLa cells expressing the alpha1 subunit of sheep Na,K-ATPase were voltage clamped via patch electrodes containing solutions with 115 mM Na+ ...

The Na/K-ATPase or Na, K-pump utilizes the free energy of hydrolysis of ATP to actively transport Na and K ions across mammalian cell membranes. This function underlies essentially all of mammalian cell physiology. For example, in the kidney the Na, K-pump controls body Na and K balance, extracellular volume and blood pressure. The Na/K-ATPase is the receptor of digitalis steroids used to treat...

In evaluating the renal mechanisms responsible for the generation of the dysnatremias, an analysis of free water clearance (FWC) and electrolyte-free water clearance (EFWC) is often utilized to characterize the rate of urinary free water excretion in these disorders. Previous analyses of FWC and EFWC have failed to consider the relationship among plasma water Na(+) concentration ([Na(+)](pw)), ...

Insulin stimulates K+ transport by the Na+-K+-ATPase in human fibroblasts. In other cell systems, this action represents an automatic response to increased intracellular [Na+] or results from translocation of transporters from an intracellular site to the plasma membrane. Here we evaluate whether these mechanisms are operative in human fibroblasts. Human fibroblasts expressed the alpha(1) but n...

salinity is a major limitation ecological factor for plant development in arid and semi-arid regions. the ionic imbalance, deficiency of nutrients and degradation of plant metabolites are caused by saline conditions, are affected by the reduction ratio of potassium (k) then sodium (na). in this research foliar applications of humic acid (ha) for improve the absorption of k under salt stress was...

The effects of organic quaternary amines, tetraethylammonium (TEA) chloride and benzyltriethylammonium (BTEA) chloride, on Na,K pump current were examined in rat cardiac myocytes superfused in extracellular Na(+)-free solutions and whole-cell voltage-clamped with patch electrodes containing a high Na(+)-salt solution. Extracellular application of these quaternary amines competitively inhibited ...