733 T he Na-K-2Cl cotransporter (NKCC) mediates the coupled movements of Na, K, and Clacross plasma membranes of animal cells. The NKCC plays an important role in ion movements across polarized epithelia and is also known to be involved in regulating cell volume and intracellular Cllevels (Lytle and Forbush 1996, Haas and Forbush 1998). The NKCC is a member of the Na-coupled group of cation-chl...

A reduced cation reabsorption across the alveolar epithelium decreases water reabsorption from the alveoli and could diminish clearing accumulated fluid. To test whether hypoxia restricts cation transport in alveolar epithelial cells, cation uptake was measured in rat lung alveolar type II pneumocytes (AII cells) in primary culture and in A549 cells exposed to normoxia and hypoxia. In AII and A...

In the duck red blood cell, Na-K-2Cl cotransport exhibits two modes of ion movement: net cotransport and obligate cation exchange. In high-K cells, the predominant exchange is K/K (or K/Rb). In high-Na cells, it becomes Na/Na (or Na/Li). Both represent partial reactions in which a fully loaded carrier releases part of its cargo, rebinds fresh ions, and returns back across the membrane fully loa...

Objectives This study examined the dose-dependent actions of hydrogen sulfide donor sodium hydrosulphide (NaHS) on isometric contractions and ion transport in rat aorta smooth muscle cells (SMC). Methods Isometric contraction was measured in ring aortas segments from male Wistar rats. Activity of Na+/K+-pump and Na+,K+,2Cl-cotransport was measured in cultured endothelial and smooth muscle cel...

Blacks have a greater tendency to retain Na than whites. The present study sought evidence for ethnic differences in parameters reflective of Na uptake by the Na,K,2Cl cotransporter in the thick ascending limb, namely, the urine concentration and urinary excretion of certain cations before and after furosemide administration (40 mg IV). Subjects were healthy (ages 18 to 36 years). During the pr...

tubules of Rhodnius prolixus during diuresis consists of approximately 100 mmol l–1 NaCl and 80 mmol l–1 KCl (Maddrell and Phillips, 1975). Secretion of ions and osmotically obliged water by tubules of this and other species is driven primarily by an apical vacuolar-type H+-ATPase (Wieczorek et al., 1989; Maddrell and O’Donnell, 1992). It is suggested that electrogenic transport of H+ from the ...

Cyclooxygenase inhibitors, such as indomethacin and diclofenac, have well-described effects to enhance renal water reabsorption and urinary concentrating ability. Concentrating ability is regulated in part at the level of the thick ascending limb of Henle's loop, where active NaCl absorption drives the countercurrent multiplication mechanism. We used semiquantitative immunoblotting to test the ...

A number of ion channels and transporters are expressed in both the inner ear and kidney. In the inner ear, K(+) cycling and endolymphatic K(+), Na(+), Ca(2+), and pH homeostasis are critical for normal organ function. Ion channels and transporters involved in K(+) cycling include K(+) channels, Na(+)-2Cl(-)-K(+) cotransporter, Na(+)/K(+)-ATPase, Cl(-) channels, connexins, and K(+)/Cl(-) cotran...

Mechanisms that contribute to Na+ influx during and immediately after 5 min anoxia were investigated in cultured rat hippocampal neurons loaded with the Na+-sensitive fluorophore sodium-binding benzofuran isophthalate. During anoxia, an influx of Na+ in the face of reduced Na+,K+-ATPase activity caused a rise in [Na+]i. After the return to normoxia, Na+,K+-ATPase activity mediated the recovery ...