ACTIVE LI EFFLUX FROM HUMAN ERYTHROCYTES WAS SHOWN TO BE MEDIATED BY THE NA/K PUMP: (i) intracellular Li (Li(c)) activated ouabain-sensitive K influx, and (ii) a portion of the Li efflux required external K and was inhibited by ouabain. In activating K influx, Li(c) interacts with the pump like Na rather than like K-depleting the cells of orthophosphate inhibited activation of K influx by intra...

In primary cultures of neurons and astrocytes from rat brain, the cellular contents of K+ and Na+ were used to assess plasma membrane permeability in response to osmotic shock. In contrast to trypan blue exclusion, the measure of ionic content reflected both transient and permanent membrane damage, and was also applicable to aggregates of cells. In steady state, the neurons and glia exhibited a...

The open-channel conductance properties of a voltage-gated channel from sarcoplasmic reticulum were studied in planar phospholipid membranes. The channel is ideally selective for K+ over Cl- and for K+ over Ca++. In symmetrical 1 M solutions, the single-channel conductance (in pmho) falls in the order: K+ (214) > NH4+ (157) > Rb+ (125) > Na+ (72) > La+ (8.1) > Cs+ (< 3). In neutral bilayers, th...

Na, K and Cl measurements have been made on frozen sections of chick red blood cells throughout embryonic development, using electron-probe microanalysis. There is an apparent fluctuation in the levels of these elements during maturation, although the Na/K ratio remains fairly constant. The nuclear Na concentration resembles that of the cytoplasm, rather than that of the medium, at all stages. ...

In skeletal muscle, excitation may cause loss of K+, increased extracellular K+ ([K+]o), intracellular Na+ ([Na+]i), and depolarization. Since these events interfere with excitability, the processes of excitation can be self-limiting. During work, therefore, the impending loss of excitability has to be counterbalanced by prompt restoration of Na+-K+ gradients. Since this is the major function o...

The lens of the toad Bufo marinus, like that of mammals, slowly gains Na and loses K when incubated in vitro. This process is facilitated by a low temperature (5° C), iodoacetate, cyanide, or ouabain. The ratio of Na/K exchange is about 1.5. Decapsulation of the lens (following brief incubation in collagenase) did not change its ionic content. Such lenses maintained their Na levels in vitro bet...

pistachios are salt tolerant crops, but the degree of salt tolerance of pistachio cultivars grown in northern parts of yazd province, iran, is not adequately known. in order to evaluate the effect of saline water on the growth and chemical composition of pistachio seedlings, a glasshouse experiment was conducted on five cultivars of pistachio namely, hajabdolahi, hajagha-ali, jalilaghaii, paran...

Myofibroblast differentiation is a key process in pathogenesis of fibrotic diseases. Cardiac glycosides (ouabain, digoxin) inhibit Na(+)-K(+)-ATPase, resulting in increased intracellular [Na(+)]-to-[K(+)] ratio in cells. Microarray analysis suggested that increased intracellular [Na(+)]/[K(+)] ratio may promote the expression of cyclooxygenase-2 (COX-2), a critical enzyme in the synthesis of pr...

Previous studies have demonstrated that electrically induced seizures in rat result in an increased brain intracellular sodium which can be decreased by treatment with sodium diphenylhydantoin (DPH). The correlation of cation transport with membrane-oriented sodium-potassium-adenosine triphosphatase (Na-K-ATPase) prompted an investigation of the effect of DPH upon ATPase enzyme activity.Rat cer...

In order to evaluate responses of a pistachio seedling rootstock (Pistacia vera L. cv. Ghazvini) to NaCl induced salinity stress and potential protective role of exogenous spermine and spermidine on NaCl induced salinity stress, a greenhouse experiment was conducted during growing season of 2009. The NaCl treatments, involving 800, 1600, and 3200 mg NaCl per Kg of soil for 90 days, suppressed g...