absorption in rabbit outer medullary collecting duct: role of luminal carbonic anhydrase. Am. J. Physiol. 274 (Renal Physiol. 43): F139–F147, 1998.—Membrane-bound luminal carbonic anhydrase (CA) IV, by catalyzing the dehydration of carbonic acid into CO2 plus water, facilitates H1 secretion in the renal outer medullary collecting duct from the inner stripe (OMCDi). To examine the role of CA IV ...

Salinization of groundwater in semiarid regions, as a limiting factor of use, has a strategic importance. In this study, the sources of salinity, chemistry and Quality of groundwater in Robat – Khorramabad plain have been identified using geochemical methods. Using data analysis, the concentration of cations and anions are recognized as Ca2+>Na+ >Mg2+>K+ and HCO3-> Cl-> SO42+> NO3-> F-. High co...

The study determines the major ion chemistry of Teesta River catchment in Eastern Himalayan region and evaluates hydrochemical processes controlling water composition area. Water basin was neutral to alkaline condition. HCO3−, Ca2+, Na+, Mg2+ SO42- were identified as dominant ionic species Ca-Mg-HCO3 facies. Higher contribution (Ca2++Mg2+) HCO3− towards TZ+ TZ−, high ratios (Ca2++Mg2+)/(Na++K+)...

In a search for the HCO3 supply mechanisms to the enterocyte we cloned and sequenced an intestinal subtype of the NaHCO3 cotransporter isoform I (dNBC1), which turned out to be identical to the pancreatic NBC1 subtype (pNBC1). Within the intestine, we found particularly high NBC1 expression levels in the duodenum and proximal colon. Experiments with stripped rabbit duodenum in Ussing-chambers r...

Bacterial infection of the kidney is associated with renal tubule dysfunction and dysregulation of systemic electrolyte balance. Whether bacterial molecules directly affect renal tubule transport is unknown. We examined the effects of LPS on HCO3(-) absorption in the isolated rat and mouse medullary thick ascending limb (MTAL). LPS decreased HCO3(-) absorption when added to bath or lumen. The M...

The role of buffering of the high pericardial fluid [HCO3~] of the turtle, Chrysemys picta bellii Gray, was evaluated during prolonged anoxia at 3 and 10°C. At 3°C, pericardial fluid samples were collected from groups of animals after 0, 1, 2, 4 and 8 weeks of anoxia, and the ionic composition of these samples was compared to plasma values from the same animals. At 10 °C, pericardial and plasma...

Sodium-linked and sodium-independent HCO3-/Cl- antiport was measured under different conditions in a number of cell lines. Transport of HCO3- was estimated from its effect on intracellular pH (pHi) measured with the fluorescent probe 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein. The associated ion fluxes were estimated from the transport of 36Cl- and 22Na+. Na+-dependent and Na+-independent H...

Electrogenic cotransport of Na+ with HCO3- has been reported in numerous tissues. It has always been shown with a net transfer of negative charge, but in some situations achieves net outward transport of both species with a stoichiometry of at least three HCO3- ions per Na+ ion (3:1), and in other situations achieves net inward transport of both species and has a stoichiometry of at most two HC...

Hydroponic culture solutions containing bicarbonate (HCO3 ) may be used to screen crops such as soybeans (Glycine max) for resistance to iron (Fe) deficiency or chlorosis. Some successful methods use sodium bicarbonate (NaHCO3) in combination with elevated partial pressures of carbon dioxide (CO2) to buffer pH and elevate bicarbonate. Replacing NaHCO3 with magnesium bicarbonate [Mg(HCO3)2] as t...