Membrane potentials and conductances, and intracellular ionic activities were studied in isolated perfused collecting tubules of K+-adapted Amphiuma. Intracellular Na+ (aNai) and K+ (aKi) activities were measured, using liquid ion-exchanger double-barreled microelectrodes. Apical and basolateral membrane conductances were estimated by cable analysis. The effects of inhibition of the apical cond...

This paper recounts recent uwork concerning the Na aiid K permeability of red blood cells. The discussion deals principally with results derived from isolated red-cell membranes, or ghosts. Using defined isolation techniques, a system of ghosts is described in which Na is actively pumped. Like intact cells, the pump requires extracellular K and energy derived from the metabolism. The source of ...

This paper recounts recent uwork concerning the Na aiid K permeability of red blood cells. The discussion deals principally with results derived from isolated red-cell membranes, or ghosts. Using defined isolation techniques, a system of ghosts is described in which Na is actively pumped. Like intact cells, the pump requires extracellular K and energy derived from the metabolism. The source of ...

Alterations of cellular function of Na+,K+-adenosine triphosphatase (ATPase; Na+-K+ pump) have been implicated in the pathophysiology of essential hypertension. Therefore, this aspect of red blood cell (RBC) Na metabolism was studied in black men with newly diagnosed, untreated essential hypertension (NEH) and a normotensive control group. RBC Na content, Na+-K+ pump number (ouabain binding sit...

The sarcolemmal Na(+)-K(+) pump, pivotal in cardiac myocyte function, is inhibited by angiotensin II (ANG II). Since ANG II activates NADPH oxidase, we tested the hypothesis that NADPH oxidase mediates the pump inhibition. Exposure to 100 nmol/l ANG II increased superoxide-sensitive fluorescence of isolated rabbit ventricular myocytes. The increase was abolished by pegylated superoxide dismutas...

This paper recounts recent uwork concerning the Na aiid K permeability of red blood cells. The discussion deals principally with results derived from isolated red-cell membranes, or ghosts. Using defined isolation techniques, a system of ghosts is described in which Na is actively pumped. Like intact cells, the pump requires extracellular K and energy derived from the metabolism. The source of ...

Studies were undertaken to explore the mechanism of stimulation of the Na/K pump in LK sheep erythrocytes by anti-L antibody. First, the numbers of functioning pump sites were determined by correlating [3H]ouabain binding with levels of inhibition of the pump. Untreated (control) cells had approximately 41 pumps per cell, and anti-L treatment caused an increase in the number of functioning pump...

Aldosterone elevates Na /K /2Cl cotransporter activity in rabbit cardiomyocytes within 15 min, an effect blocked by K-canrenoate and thus putatively mineralocorticoid receptor mediated. Increased cotransporter activity raises intracellular [Na ] sufficient to produce a secondary increase in Na -K pump activity; when this increase in intracellular [Na ] is prevented, a rapid effect of aldosteron...

Because the activity of the sodium pump (Na-K-ATPase) influences the secretion of aldosterone, we determined how extracellular potassium (K(o)) and calcium affect sodium pump activity in rat adrenal glomerulosa cells. Sodium pump activity was measured as ouabain-sensitive (86)Rb uptake in freshly dispersed cells containing 20 mM sodium as measured with sodium-binding benzofluran isophthalate. I...

Brain neurons can transmit signals using a flow of Na+ and K+ ions, which produce an electrical spike called an action potential (AP) (Hodgkin and Huxley, 1952). After an AP, the Na+/K+ pump resets the arrangement of Na+ and K+ ions back to their original positions so that the neuron is then ready to relay another AP when it is called upon to do so (Glitsch, 2001). So, the Na+/K+ pump has a “ho...