Protein kinase C can activate NADPH oxidase and induce glutathionylation of the β1-Na(+)-K(+) pump subunit, inhibiting activity of the catalytic α-subunit. To examine if signaling of nitric oxide-induced soluble guanylyl cyclase (sGC)/cGMP/protein kinase G can cause Na(+)-K(+) pump stimulation by counteracting PKC/NADPH oxidase-dependent inhibition, cardiac myocytes were exposed to ANG II to ac...

TO THE EDITOR: Since the active reuptake of fiber K lost during action potentials in contracting muscles is limited by the maximal transport capacity of fiber Na -K pumps, substantial effort has been made to determine how this capacity is regulated during exercise. The methods employed includes ouabain-based determination of muscle Na -K pump content, 3-Omethylfluorescein phosphate-based determ...

Transepithelial sodium transport is a process that involves active Na(+) transport at the basolateral membrane of the epithelial cell. This process is mediated by the Na(+)/K(+) pump, which exchanges 3 internal Na(+) by 2 external K(+) inducing a net charge movement and the second Na(+) pump, which transports Na(+) accompanied by Cl(-) and water. It has been suggested that this pump could also ...

Regulation of the Na,K pump in intact cells is strongly associated with the level of intracellular Na+. Experiments were carried out on intact, isolated sheep Purkinje strands at 37 degrees C. Membrane potential (Vm) was measured by an open-tipped glass electrode and intracellular Na+ activity (aNai) was calculated from the voltage difference between an Na+-selective microelectrode (ETH 227) an...

TO THE EDITOR: Since the active reuptake of fiber K lost during action potentials in contracting muscles is limited by the maximal transport capacity of fiber Na -K pumps, substantial effort has been made to determine how this capacity is regulated during exercise. The methods employed includes ouabain-based determination of muscle Na -K pump content, 3-Omethylfluorescein phosphate-based determ...

We studied preBötzinger Complex (preBötC) inspiratory interneurons to determine the cellular mechanisms that influence burst termination in a mammalian central pattern generator. Neonatal mouse slice preparations that retain preBötC neurons generate respiratory motor rhythms in vitro. Inspiratory-related bursts rely on inward currents that flux Na(+), thus outward currents coupled to Na(+) accu...

Ouabain-sensitive (OS) and -resistant (OR) Rb(+) influx was examined in three sublines of U937 cells to compare alterations of K(+) channel permeability and the Na(+),K(+)-ATPase pump leading to the shift in ion and water balance during apoptosis induced by 0.2 and 1microM staurosporine (STS) for 4-5 h. Cell K(+), Rb(+), Na(+) and Cl(-) content was determined by flame photometry and (36)Cl dist...

AIMS Elevation of intracellular Na in the failing myocardium contributes to contractile dysfunction, the negative force-frequency relationship, and arrhythmias. Although phospholemman (PLM) is recognized to form the link between signalling pathways and Na/K pump activity, the possibility that defects in its regulation contribute to elevation of intracellular Na has not been investigated. Our ai...

The sodium pump (or Na-K-ATPase) is essential to the function of animal cells. Publication of the related calcium pump (SERCA) structure together with several recent results from a variety of approaches allow us to propose a mechanistic model to answer the question: "How does the sodium pump pump?"

Electrophysiologic responses were recorded in vitro from the retina of the toad, Bufo marinus. In the isolated retinal pigment epithelium (RPE)-choroid preparation, a decrease in the K+ concentration outside the apical membrane evoked a sequence of trans-epithelial (TEP) and membrane potential changes. A hyperpolarization originating at the RPE apical membrane that increased the TEP was followe...