Insulin enhances Na(+)-K(+) pump activity in various noncardiac tissues. We examined whether insulin exposure in vitro regulates Na(+)-K(+) pump function in rabbit ventricular myocytes. Pump current (I(p)) was measured using the whole-cell patch-clamp technique at test potentials (V(m)s) from -100 to +60 mV. When the Na(+) concentration in the patch pipette ([Na](pip)) was 10 mM, insulin caused...

The effects of organic quaternary amines, tetraethylammonium (TEA) chloride and benzyltriethylammonium (BTEA) chloride, on Na,K pump current were examined in rat cardiac myocytes superfused in extracellular Na -free solutions and whole-cell voltage-clamped with patch electrodes containing a high Na -salt solution. Extracellular application of these quaternary amines competitively inhibited extr...

It has been hypothesized that the light-evoked rod hyperpolarization (the receptor potential) initiates the light-evoked decrease in extracellular potassium ion concentration, [K+]o, in the distal retina. The hypothesis was tested using the isolated, superfused retina of the toad, Bufo marinus; the receptor potential was recorded intracellularly from red rods, and [K+]o was measured in the phot...

Dear Sir: The purpose of this communication is to show that the Ca ion concentration gradient across the sarcoplasmic reticulum membrane of a resting skeletal muscle cell is close to what would be predicted for the equilibrium state of the ATP-driven Ca pump. The Na and K gradients across the plasma membranes of erythrocytes or of a resting squid axon, however, fall far short of the predicted e...

The effects of various inhibitors on the membrane potential, resistance, and K(+) permeability of Chara corallina were measured, providing evidence that there is an electrogenic pump in the membrane. It was found that: (a) 5.0 mum carbonyl cyanide m-chlorophenyl hydrazone depolarizes the membrane potential and increases the membrane resistance. This inhibition is faster in the dark than in the ...

Electrogenicity of the Na(+)/K(+) pump has the capability to generate a large negative membrane potential independently of ion-channel current. The high background membrane resistance of arterioles may make them susceptible to such an effect. Pump current was detected by patch-clamp recording from smooth muscle cells in fragments of arterioles (diameter 24-58 microm) isolated from pial membrane...

A study of the mechanisms of the effects of amphotericin B and ouabain on cell membrane and transepithelial potentials and intracellular K activity (alpha Ki) of Necturus gallbladder epithelium was undertaken with conventional and K-selective intracellular microelectrode techniques. Amphotericin B produced a mucosa-negative change of transepithelial potential (Vms) and depolarization of both ap...

Several lines of experimental evidence are presented suggesting that the L antigens in low potassium (LK) sheep red cells are associated with separate Na(+)K(+) pump flux is distinct from the action of anti-L(l) on K(+) leak flux, implying that K(+) leak transport sites may not be converted into active pumps by the L antiserum. Treatment of LK red cells with trypsin completely abolished both th...

Benziane B, Chibalin AV. Skeletal muscle sodium pump regulation: a translocation paradigm. Am J Physiol Endocrinol Metab 295: E553–E558, 2008. First published April 22, 2008; doi:10.1152/ajpendo.90261.2008.—The skeletal muscle sodium pump plays a major role in the removal of K ions from the circulation postprandial, or after a physical activity bout, thereby preventing the development of hyperk...