In recent years, an electrogenic 2Na+/1H+ antiporter has been identified in a variety of invertebrate epithelial brush-border membranes of gut, kidney and gill tissues. The antiporter differs significantly in its physiological properties from the electroneutral 1Na+/1H+ antiporter proposed for vertebrate cells. In all invertebrate cells examined, the antiporter displayed a 2:1 transport stoichi...

In recent years, many groups of clinical scientists have become interested in measuring transmembrane ion fluxes of various kinds in patients with different diseases. The ion fluxes of interest have included the ouabainsensitive Na+/K+ pump, the loop-diuretic-sensitive Na+/ K+ co-transport system, the phloretin-sensitive Na+/Na+ (or Na+/Li+ ) countertransport system, and the amiloridesensitive ...

Influx ofd-aspartate (d-Asp),l-glutamate (l-Glu), and serine (Ser) across the brush-border membrane of the intact mucosa from rabbit ileum has been examined. l-Glu influx is chloride independent and completely sodium dependent.d-Asp andl-Glu share a transport system with a maximum transport rate of 1 μmol ⋅ cm-2 ⋅ h-1and an apparent affinity constant ( K ½) of ∼0.3 mM. The function of this tran...

Studying the molecular regulation of the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) is important for understanding how the kidney contributes to blood pressure regulation. Until now, a native mammalian cell model to investigate this transporter remained unknown. Our aim here is to establish, for the first time, a primary distal convoluted tubule (DCT) cell culture exhibiting transcellul...

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...

SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) on transport vesicles and target membranes are crucial for vesicle targeting and fusion. They form SNARE complexes, which contain four α-helical SNARE motifs contributed by three or four different SNAREs. Most SNAREs function only in a single transport step. The yeast SNARE Vti1p participates in four distinct SNARE c...

Cell-swelling, induced by a hyposmotic shock, activates the release of taurine from lactating rat mammary tissue explants. The degree of stimulation of taurine efflux was dependent upon the extent of cell-swelling. Volume-sensitive taurine release was attenuated by the anion transport inhibitors NPPB, DIOA, DIDS, niflumate, flufenamate, mefenamate and diiodosalicylate but not by salicylate. Cel...

The most effective diuretic drugs inhibit salt transport by renal distal tubular cells by binding to cell-type specific apical transport proteins. For the three successive cortical distal segments (Figure 1) the specific transport proteins have been recently cloned and located: the Na-K-2C1 cotransporter (bumetanide-sensitive cotransporter, BSCl), binding loop diuretics such as furosemide, is l...