An electroneutral Na+/H+exchange mechanism (dimethylamiloride inhibitable, Li+ sensitive, and Ca2+ insensitive) was identified in brush-border membrane vesicles (BBMV) from Kuruma prawn hepatopancreas by monitoring Na+-dependent H+ fluxes with the pH-sensitive dye acridine orange and measuring22Na+uptake. Kinetic parameters measured under short-circuited conditions were the Na+ concentration th...

Na+/H+ exchange activity in whole cells of the halotolerant alga DunaIfeila saUna can be elicited by intracellular acidification due to addition of weak acids at appropriate external pH. The changes in both intracellular pH and Nat were followed. Following a mild intracellular acidification, intracellular Nat content increased dramatically and then decreased. We interpret the phase of Nat influ...

We sought to determine whether the impairment of sodium pump activity and Na+/H+ exchange reported in tumorigenic cells was specific to these cells or more general. Sodium pump activity and Na+/H+ exchange were measured in erythrocytes from 49 cancer patients and 51 healthy subjects. Cancer patients with a newly detected cancer or in relapse and without associated pathologies known to modify th...

In recent years, an electrogenic 2Na + /1H + antiporter has been identified in a variety of invertebrate epithelial brush-border membranes of gut, kidney and gill tissues. The antiporter differs significantly in its physiological properties from the electroneutral 1Na + /1H + antiporter proposed for vertebrate cells. In all invertebrate cells examined, the antiporter displayed a 2:1 transport s...

A spontaneous mutant of Methanothermobacter thermautotrophicus resistant to the Na(+)/H(+) antiporter inhibitor harmaline was isolated. The Na(+)/H(+) exchange activity in the mutant cells was remarkably decreased in comparison with wild-type cells. Na(+)/H(+) antiport activity of wild-type cells grown in the high Na(+) concentration (125 mmol/l) was significantly increased as compared to the c...

In recent years, an electrogenic 2Na+/1H+ antiporter has been identified in a variety of invertebrate epithelial brush-border membranes of gut, kidney and gill tissues. The antiporter differs significantly in its physiological properties from the electroneutral 1Na+/1H+ antiporter proposed for vertebrate cells. In all invertebrate cells examined, the antiporter displayed a 2:1 transport stoichi...

Hydrogen sulfide (H2S) and nitric oxide (NO) are emerging as messenger molecules involved in the modulation of plant physiological processes. Here, we investigated a signalling network involving H2S and NO in salt tolerance pathway of barley. NaHS, a donor of H2S, at a low concentration of either 50 or 100 μM, had significant rescue effects on the 150 mM NaCl-induced inhibition of plant growth ...

Protein isoprenylation is a post-translational modification essential for the biological activity of G-proteins. Inhibition of protein isoprenylation by lovastatin (LOV) induces apoptosis in HL-60 cells, a process of active cell death characterized by the internucleosomal degradation of genomic DNA. In this article we show that LOV-induced apoptosis is associated with intracellular acidificatio...

Regulation of intracellular pH (pHi) following acidosis induced by NH4+/NH3 exposures was re-investigated in a crayfish stretch receptor neurone using H+and Na+selective microelectrodes. All experiments were performed in nominally HCO3–/CO2free salines. From studies in Na+-free saline and from electrochemical calculations, we concluded that pHi regulation was dependent on extracellular Na+ conc...

To investigate the relationship between red blood cell Na+/H+ exchange (EXC) and genetic factors in hypertension, we studied the maximal rate of the antiporter (mmol/liter cell x hr; flux units = FU) in three strains of genetically hypertensive rats. Salt-resistant Dahl rats (DR) were normotensive under low (0.02%) and high (8%) NaCl diets, while salt-sensitive Dahl rats (DS) became markedly hy...