Marinobufagenin (MBG), an endogenous ligand of -1 Na/K-ATPase, becomes elevated and contributes to hypertension in NaCl-loaded Dahl-S rats (DS). Protein kinase C (PKC) phosphorylates -1 Na/K-ATPase and increases its MBG sensitivity. Cicletanine, an antihypertensive compound with PKC-inhibitory activity, reverses MBG-induced Na/K-ATPase inhibition and vasoconstriction. We hypothesized that incre...

Na+ overload and secondary Ca2+ influx via Na+/Ca2+ exchanger are key mechanisms in cardiomyocyte contracture and necrosis during reperfusion. Impaired Na+/K+-ATPase activity contributes to Na+ overload, but the mechanism has not been established. Because Na+/K+-ATPase is connected to the cytoskeleton protein fodrin through ankyrin, which are substrates of calpains, we tested the hypothesis tha...

The activities of Na-K-ATPase and Na-K-2Cl cotransporter (NKCC1) were studied in the aorta, heart, and skeletal muscle of streptozotocin (STZ)-induced diabetic rats and control rats. In the aortic rings of STZ rats, the Na-K-ATPase-dependent (86)Rb/K uptake was reduced to 60.0 +/- 5.5% of the control value (P < 0.01). However, Na-K-ATPase activity in soleus skeletal muscle fibers of STZ rats an...

By maintaining the Na(+) and K(+) transmembrane gradient mammalian Na,K-ATPase acts as a key regulator of neuronal electrotonic properties. Na,K-ATPase has an important role in synaptic transmission and memory formation. Accumulation of beta-amyloid (Aβ) at the early stages of Alzheimer's disease is accompanied by reduction of Na,K-ATPase functional activity. The molecular mechanism behind this...

PURPOSE The Na(+)-/K(+)-dependent ATPase (Na,K-ATPase) expressed in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. The role of insulin in the regulation of Na,K-ATPase activity and pump function in corneal endothelial cells was investigated. METHODS Confluent monolayers of mouse corneal endothelial cells were expo...

Capsazepine (CPZ) inhibits Na+,K+-ATPase-mediated K+-dependent ATP hydrolysis with no effect on Na+-ATPase activity. In this study we have investigated the functional effects of CPZ on Na+,K+-ATPase in intact cells. We have also used well established biochemical and biophysical techniques to understand how CPZ modifies the catalytic subunit of Na+,K+-ATPase. In isolated rat cardiomyocytes, CPZ ...

The effect of Benfluron on the heart sarcolemmal (Na+, K+)-ATPase and Mg(2+)-ATPase activities was studied in crude membrane fraction as well as in purified sarcolemmal membranes isolated from rat heart. Benfluron in concentration range 10(-7) -5 x 10(-5) mol.l-1 did not exert any effect on ATPase activities studied. 10(-4) mol.l-1 Benfluron was stimulatory towards (Na+, K+)-ATPase, while Mg(2+...

Intracellular [Na] is approximately 3 mmol/L higher in heart failure (HF; in our arrhythmogenic rabbit model), and this can profoundly affect cardiac Ca and contractile function via Na/Ca exchange and Na/H exchange. Na/K-ATPase is the primary mechanism of Na extrusion. We examine here in HF rabbits (and human hearts) expression of Na/K-ATPase isoforms and phospholemman (PLM), a putative Na/K-AT...

homocysteine thiolactone was demonstrated to inhibit the growth of 10–12-day-old chicken embryo cardiac tissue explants at 7 × 10−9 −1 × 10−3 m concentrations in a dose-dependent manner. the maximal cardiotoxic effect of homocysteine thiolactone was detected at 1 × 10−3 m, which corresponds to severe hyperhomocysteinemia. the results of experiments on culturing of cardiac tissue explants in the...

Aldosterone-induced intestinal Na(+) absorption is mediated by increased activities of apical membrane Na(+)/H(+) exchange (aNHE3) and basolateral membrane Na(+)-K(+)-ATPase (BLM-Na(+)-K(+)-ATPase) activities. Because the processes coordinating these events were not well understood, we investigated human intestinal Caco-2BBE cells where aldosterone increases within 2-4 h of aNHE3 and alpha-subu...