Na(+)/H(+) antiporters are integral membrane proteins that exchange Na(+) for H(+) across the cytoplasmic membrane and many intracellular membranes. They are essential for Na(+), pH and volume homeostasis, which are crucial processes for cell viability. Accordingly, antiporters are important drug targets in humans and underlie salt-resistance in plants. Many Na(+)/H(+) antiporters are tightly r...

The Na+/H+ antiport is an important regulator of cellular volume, pH and Na+ concentration in mammalian cells. The stoichiometry of this antiporter has previously been shown to be a 1:1 exchange of internal H+ for external Na+. We have investigated this stoichiometry in human leucocytes by using a novel intracellular pH-clamping technique and measuring 22Na+ influx and H+ efflux in the same cel...

To test the hypothesis that internal ion imbalances at high pH are caused by altered branchial ion transporting capacity and permeability, radiotracers (24Na+ and 36Cl-) were used to measure ion movements across the gills of intact rainbow trout (Oncorhynchus mykiss) during 3 d exposure to pH 9.5. At control pH (pH 8.0), the trout were in net ion balance, but by 8 h at high pH, 60%-70% reductio...

Phorbol-12,13-dibutyrate, epidermal growth factor, and insulin raised the intracellular pH ([pH]i), presumably through the activation of a Na+/H+ antiporter. Addition of amiloride or replacement of extra-cellular Na+ by choline which abolishes the cytoplasmic alkalinization prevented the stimulation of hexose transport by these agents. Furthermore, monensin, a Na+/H+ ionophore which increases t...

In Amphiuma red blood cells, the Na/H exchanger has been shown to play a central role in the regulation of cell volume following cell shrinkage (Cala, P. M. 1980. Journal of General Physiology. 76:683-708.) The present study was designed to evaluate the existence of pH regulatory Na/H exchange in the Amphiuma red blood cell. The data illustrate that when the intracellular pHi was decreased belo...

Na+ was found to be essential for the accumulation of sucrose by Vibrio alginolyticus. Sucrose uptake was completely inhibited by the addition of proton conductor at neutral pH, but not at alkaline pH, where the primary electrogenic Na+ pump generates the Na+ electrochemical gradient. We therefore conclude that sucrose transport is driven by the electrochemical potential of Na+ in this organism.

this study was carried out on 10 crossbred male sheep aged 1-1.5 year. an innervated crosskopf abomasal fundic pouch was made in each animal and effect o f starvation an d feeding on abomasal volume and composition were assesed . the results indicated that during starvation, volume of secretion , total acidity and k concentration decreased to a low level, while ph and na concentration reached h...

Since both sodium L-ascorbate (Na-AsA) and sodium saccharin (Na-Sac) promote two-stage bladder carcinogenesis in rats, synergism of the two chemicals was investigated with special reference to the role of urinary pH and Na+ concentration. Male F344 rats were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in the drinking water for 4 wk and then treated with basal diet containing 5% Na-Sac, 5%...

Cytoplasmic pH (pH(i)) was evaluated during Na(+)-glucose cotransport in Caco-2 intestinal epithelial cell monolayers. The pH(i) increased by 0.069 +/- 0.002 within 150 s after initiation of Na(+)-glucose cotransport. This increase occurred in parallel with glucose uptake and required expression of the intestinal Na(+)-glucose cotransporter SGLT1. S-3226, a preferential inhibitor of Na(+)/H(+) ...

Na(V) channels play a crucial role in neuronal and muscle excitability. Using whole-cell recordings we studied effects of low extracellular pH on the biophysical properties of Na(V)1.2, Na(V)1.4, and Na(V)1.5, expressed in cultured mammalian cells. Low pH produced different effects on different channel subtypes. Whereas Na(V)1.4 exhibited very low sensitivity to acidosis, primarily limited to p...