The transport properties of the rabbit peritoneal polymorphonuclear leukocyte (PMN) plasma membrane to Na+, K+, and Ca2+ have been characterized. The use of a silicone oil centrifugation technique provided a rapid and reliable method for measuring ion fluxes in these cells. Na+ and K+ movements across PMN membranes were found to be rapid. The value for the unifirectional steady-state fluxes (in...

Sodium derived from the blood is known to accumulate in brain tissue during the early stages of incomplete ischemia. Our present studies were undertaken to determine the relation between blood-brain barrier sodium transport and the development of ischemic brain edema. Incomplete cerebral ischemia was produced in gerbils by ligation of the left common carotid artery under ether anesthesia. Follo...

Electrical stimulation of isolated adult rat heart cells in suspension at 4 Hz resulted in a fourfold increase in the rate of sodium influx and efflux across the sarcolemma, with no change in total cell sodium, as measured with 22Na. The magnitude of stimulation-dependent sodium fluxes under these conditions averaged 17 nmol/min/mg protein. The increased rate of efflux was inhibited by tetrodot...

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 ...

We investigated in a physiological salt solution (PSS) containing HCO3the 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 pH; from an equivalent intracellular acidosis was more rapid when the cells were in...

Na+/H+ exchanger isoform and the effect of high osmolality on its function was studied in cultured renal epithelial cells (LLC-PK1 and OK). Using NHE-3-specific antibody, immunoblots of luminal membranes from LLC-PK1 and OK cells specifically labeled proteins with molecular masses 90 and 95 kDa, indicating that NHE-3 is the isoform expressed on the luminal membranes of these epithelia. Proximal...

We describe the use of an in vivo human bronchial xenograft model of cystic fibrosis (CF) and non-CF airways to investigate pathophysiological alterations in airway surface fluid (ASF) volume (Vs) and Cl content. Vs was calculated based on the dilution of an impermeable marker, [3H]inulin, during harvesting of ASF from xenografts with an isosmotic Cl-free solution. These calculations demonstrat...