Sodium Pump

Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

Sodium Pump


(or sodium-potassium pump), in biochemistry, a membrane mechanism that maintains a definite ratio of Na + and K + ions in cells by active transport of the ions against electrochemical and concentration gradients. The cells of most tissues contain more K + ions than Na + ions, whereas the fluids reaching the tissues (blood, lymph, and intercellular fluid) contain significantly higher concentrations of Na +. A certain number of ions continuously enters and leaves the cells. The passive transport of cations (transfer of ions through the membrane by means of a system of special channels along the electrochemical and concentration gradients) is, on the average, compensated by active ion transport.

The function of the sodium pump is related to the transfer of metabolites into the cells and, in the case of nerve and muscle fibers, is also related to the mechanism of excitation. The active transfer of Na + from the cell is associated with the transport of K + in the opposite direction and is accomplished by a special enzyme system, the sodium-potassium transport system, which is stimulated by adenosine triphosphatase localized in the cell membrane. By hydrolyzing adenosine triphosphate (ATP), adenosine triphosphatase liberates energy, which is expended on the active transfer of cations. The working of the sodium pump on the whole depends on the level of cell metabolism.


References in periodicals archive ?
For example, when primary sodium pump trips, an operator expects flow of the coolant to stop.
purpuratus was paralleled by a concomitant increase in the total activity of the sodium pump (Fig.
Because the sodium pump consumes such a large portion of cellular energy metabolism (e.
Endogenous sodium pump inhibition: current status and therapeutic opportunities.
Understanding the sodium pump and its relevance to disease.
Endogenous mammalian cardenolides are thought to be effector ligands that regulate the sodium pump as a receptor.
3], ouabain, dihydroouabain, porcine cerebral cortex, all reagents for catalytic inhibition of the sodium pump [ATP, ammonium molybdate, Tween 80, and bovine serum albumin (BSA)] as well as goat antirabbit horseradish peroxidase conjugate, phosphate-buffered saline (PBS)-Tween (pH 7.
For years scientists suspected that chloride cells used their sodium pumps to rid the body of excess sodium ions.
1]H NMR) [4] spectroscopic measurements have demonstrated that the adrenal and hypothalamic sodium pump inhibitors are indistinguishable from authentic ouabain.
Those findings strongly support the concept of differential regulation of the sodium pump genes.
The rationale for using Fab fragments to reduce toxic effects of digoxin is their greater affinity for digoxin when compared with the sodium pump.
Early data suggested that the unidentified hormone slowed the activity of cellular sodium pumps -- membrane proteins that help transport sodium out of cells.