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 ...

l. Radioisotopic studies with 22Na were conducted in vitro on nerve cords of the grasshopper Melanoplus differentialis. 2. The total uptake of 22Na by nerve cords is significantly decreased by the presence of 5 mM azide in the incubation medium. 3. Six components were extracted from desaturation curves of nerve cords, after which some residual radioactivity remained in the majority of cases. 4....