The mechanism of basolateral membrane base transport was examined in the in vitro microperfused rabbit proximal convoluted tubule (PCT) in the absence and presence of ambient CO2/HCO3- by means of the microfluorometric measurement of cell pH. The buffer capacity of the cells measured using rapid NH3 washout was 42.8 +/- 5.6 mmol.liter-1.pH unit-1 in the absence and 84.6 +/- 7.3 mmol.liter-1.pH ...

kahman is the most beneficial river in alashtar city for agriculture and aquiculture. as hydrology processes have random nature, statistics and probability are base of analysis of these processes and time series are used for this purpose. the first step in time series analysis includes parameters variation through time. second step is to stationary data, third is normalization and forth is mode...

The effect of low pH on the kinetics of Na channel ionic and gating currents was studied in frog skeletal muscle fibers. Lowering external pH from 7.4 to 5.0 slows the time course of Na current consistent with about a +25-mV shift in the voltage dependence of activation and inactivation time constants. Similar shifts in voltage dependence adequately describe the effects of low pH on the tail cu...

Formate stimulates sodium chloride and fluid reabsorption in kidney proximal tubule; however, the exact cellular mechanism of this effect remains unknown. We hypothesized that the primary target of formate is the apical Na(+)/H(+) exchanger. Here, we demonstrate that formate directly enhances the apical Na(+)/H(+) exchanger (NHE3) activity in mouse kidney proximal tubule. In the absence of CO(2...

An in vitro experiment was conducted to evaluate the effect of different dietary minerals on phytate hydrolysis by microbial phytase enzyme and to measure the residual phytate content after phytate digestion. Calcium (0, 6, 8, 10 g kg of diet), Fe (0, 70, 80, 90 mg kg of diet), Zn (0, 30, 40, 50 mg kg of diet) or Na (0, 1.5, 2.5 and 3.5 g kg of diet) were incubated with a Na-phytate solution, w...

Two mechanisms of H+ ion secretion in the proximal tubule that mediate bicarbonate reabsorption have been identified: the brush border Na/H exchanger and electrogenic H+ ion secretion. Angiotensin II (AII) has been shown to be a regulator of the luminal Na+/H+ exchanger and the basolateral Na+/HCO3- cotransporter. In the present study, we examined the effects of AII on H+-ATPase activity in iso...

Ammonia is an abundant fermentation product in the forestomachs of ruminants and the intestine of other species. Uptake as NH3 or NH4+ should modulate cytosolic pH and sodium-proton exchange via Na+/H+ exchanger (NHE). Transport rates of Na+, NH4+, and NH3 across the isolated rumen epithelium were studied at various luminal ammonia concentrations and pH values using the Ussing chamber method. T...

A adsorção de cobre sobre óxido de alumínio modificado, em meio aquoso, foi avaliada neste trabalho. A modificação do Al2O3 foi realizada através da adsorção de ácido húmico comercial à sua superfície. A adsorção do cobre foi governada por fatores tais como pH, teores de matéria orgânica (particulada e dissolvida) e concentração do material sólido. A adsorção do metal aumentou com o aumento do ...

A pH-sensitive cAMP-gated cation current (I(Na,cAMP)) is widely distributed in neurons of the feeding motor networks of gastropods. In the sea slug Pleurobranchaea this current is potentiated by nitric oxide (NO), which itself is produced by many feeding neurons. The action of NO is not dependent on either cGMP or cAMP signaling pathways. However, we found that NO potentiation of I(Na,cAMP) in ...

Chinese hamster lung fibroblasts (CCl39) possess in their plasma membrane an amiloride-sensitive Na+/H+ antiport, activated by growth factors. Measurements of intracellular pH (pHi), using equilibrium distribution of benzoic acid, provide evidence for a major role of this antiport in 1) regulation of cytoplasmic pH, in response to an acute acid load or to varying external pH values, and 2) the ...