Fluoride and vanadate are known to induce the Ca(2+)-dependent K+ efflux. We found that both agents concomitantly induced the Ca(2+)-dependent 22Na+ influx. The extent of the Ca(2+)-dependent 22Na+ influx induced by vanadate was very small in human red blood cells but clearly visible in guinea-pig red blood cells. The effect of fluoride has been studied in human red blood cells only. The 22Na+ ...

We report the purification of acetylcholine receptors with active agonist-regulated cation channels from Torpedo californica electric organ tissue by five methods. In one method, previously used by others, contaminating proteins were removed from partially purified membranes by alkaline extraction, preserving membrane integrity throughout the procedure. In the other four methods, acetylcholine ...

The effect of ionizing radiation on neuronal membrane function was assessed by measurement of neurotoxin-stimulated 22Na+ uptake by rat brain synaptosomes. High-energy electrons and gamma photons were equally effective in reducing the maximal uptake of 22Na+ with no significant change in the affinity of veratridine for its binding site in the channel. Ionizing radiation reduced the veratridine-...

Na movement across the plasma membranes of confluent monolayers of monkey kidney epithelial cells (BSC-1) was studied using 22Na+ uptake and efflux techniques in the presence of 10(-4) M ouabain. In the presence of 28 mM bicarbonate, uptake was inhibited by both 10(-3) M amiloride and 10(-3) M 4,4'diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). In DIDS-pretreated cells, 10(-3) M amiloride l...

Uptake of 22Na+ and 45Ca2+ into everted membrane vesicles from Escherichia coli was measured with imposed transmembrane pH gradients, acid interior, as driving force. Vesicles loaded with 0.5 M KCl were diluted into 0.5 M choline chloride to create a potassium gradient. Addition of nigericin to produce K+/H+ exchange resulted in formation of a pH gradient. This imposed gradient was capable of d...

In Bartter's syndrome, the defective renal tubular transport has been postulated to be a manifestation of a more generalized membrane abnormality. To explore this possibility, sodium concentration, ouabain-sensitive (pump transport), ouabain-resistant but furosemide-sensitive (Na-K-Cl cotransport), and ouabain- and furosemide-resistant (passive transport) 22Na effluxes were measured in erythroc...

Effects of adenosine triphosphate (ATP) and dibutyryl cyclic adenosine monophosphate (dbc AMP) on the Na+-K+ pump of cell membrane were studied by testing the effects of these nucleotides on the 22Na+-efflux from frog skeletal muscle fibres. The rate coefficient of 22Na+-efflux was found to be significantly increased by ATP 3 mM. Dbc AMP 3 mM showed no demonstrable effect. These results support...

The development of the functional properties of the sodium channel of chick skeletal muscle grown in culture was studied using 22Na uptake and electrophysiological techniques. In accord with the biochemical data in the preceding paper (Baumgold, J., J. B. Parent, and I. Spector (1983) J. Neurosci. 3: 995-1003), the functional manifestations of sodium channel expression are initiated shortly aft...

Acute inflammation was induced in rats by subcutaneous implantation of plastic sponges, and the penetration of salicylate and naproxen into the inflammatory exudate was studied after oral dosing with these compounds. The penetration of intravenously administered 22Na and 125I-albumin was also studied. It was found that salicylate and 22Na penetrated very rapidly, reaching maximum concentration ...