We investigated in a physiological salt solution (PSS) containing HCO3- the intracellular pH (pHi) regulating mechanisms in smooth muscle cells cultured from human internal mammary arteries, using the pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) and 22Na+ influx rates. The recovery of pHi from an equivalent intracellular acidosis was more rapid when the cells were ...

The purpose of the present study was to determine whether isohydric changes in HCO3 concentration and Pco 2directly affect apical Na-dependent Pi(Na-Pi) cotransport in OK cells (opossum kidney cell line). Cells were kept at either 44 mM NaHCO3/10% CO2, pH 7.4 (high-HCO3/CO2condition), or 22 mM NaHCO3/5% CO2, pH 7.4 (low-HCO3/CO2condition) (for 14-24 h). Incubation in lower HCO3/CO2concentration...

Preparations of pyruvate carboxylase catalyse the cleavage of MgATP in the absence of pyruvate and acetyl-CoA. The rate of this cleavage is higher in the presence of HCO3- than in its absence. Incubation of the enzyme preparations with an excess of the pyruvate carboxylase inhibitor, avidin, completely abolishes the pyruvate carboxylating activity of the enzyme preparations but only abolishes t...

32 Sepsis and endotoxemia induce defects in renal tubule function but the mechanisms are 33 poorly understood. Recently we demonstrated that lipopolysaccharide (LPS) inhibits HCO3 34 absorption in the medullary thick ascending limb (MTAL) through activation of different Toll-like 35 receptor 4 (TLR4) signaling pathways in the basolateral and apical membranes. Basolateral 36 LPS inhibits HCO3 ab...

Posterior isolated gills of Neohelice (Chasmagnathus) granulatus were symmetrically perfused with hemolymph-like saline of varying [HCO3-] and pH. Elevating [HCO3-] in the saline from 2.5 to 12.5 mmol/l (pH 7.75 in both cases) induced a significant increase in the transepithelial potential difference (Vte), a measure of ion transport. The elevation in [HCO3-] also induced a switch from acid sec...

1. The effect of parathyroid hormone on gastric bicarbonate secretion was determined in the anaesthetized guinea pig. Subcutaneous injections of bovine parathyroid hormone (75 U.S.P units day-1 kg-1) for 7 days caused a significant increase in HCO3- output. There was also a rise in K+ output and a slight elevation of H+ secretion. A similar increase in HCO3- output occurred after acute intraven...

HCO3 in pancreatic juice arises from the pancreatic duct cells. Secretin stimulates HCO3 secretion via a mechanism that involves activation of the adenylate cyclase pathway, activation of both basolateral K channels and the apical CFTR Cl channel, and stimulation of an apical Slc26mediated Cl/HCO3 exchanger (1). The Slc26 anion exchangers, Slc26a3 and Slc26a6, have both been localized to the ap...

OBJECTIVE There is controversy about the effects of high plasma bicarbonate concentration ([HCO3(-)]) and the CO2 response test. We analyzed the relationship between [HCO3(-)] and the variation in hydrogen ion concentration (pH) for a given change in PaCO2, and its effects upon CO2 response. DESIGN A retrospective study was carried out. SETTING Two intensive care units. PATIENTS Subjects ...

TongXie-YaoFang (TXYF) can effectively alleviate the symptoms of diarrhea-predominant irritable bowel syndrome (D-IBS) patients. However, the curative mechanism has not been fully clarified. The study was designed to investigate the effect of TXYF on the colonic ion transport induced by serotonin (5-HT) in D-IBS rats. A method of multiple stress (neonatal maternal separation (NMS) combined with...