scholarly journals Rapid decrease in cellular sodium and chloride content during cold incubation of cultured liver endothelial cells and hepatocytes

1997 ◽  
Vol 322 (3) ◽  
pp. 693-699 ◽  
Author(s):  
Elke R. GIZEWSKI ◽  
Ursula RAUEN ◽  
Michael KIRSCH ◽  
Irith REUTERS ◽  
Herbert DIEDERICHS ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Rat Hepatocytes ◽  
Chloride Content ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Surprising Result ◽  
Sodium Influx ◽  
Sodium Efflux ◽  
Uw Solution ◽  
Liver Endothelial Cells

Hypothermia, as used for organ preservation in transplantation medicine, is generally supposed to lead to an intracellular accumulation of sodium, and subsequently of chloride, via inhibition of the Na+/K+-ATPase. However, on studying the cellular sodium concentration of cultured liver endothelial cells using fluorescence microscopy, we found a 55% decrease in the cellular sodium concentration after 30 min of cold incubation in University of Wisconsin (UW) solution. To confirm this surprising result, we set up a capillary electrophoresis method that allowed us to determine the cellular contents of inorganic cations and of inorganic anions. Using this method we measured a decrease in the cellular sodium content from 104±11 to 55±4 nmol/mg of protein, accompanied by a decrease in the chloride content from 71±9 to 25±5 nmol/mg of protein, after 30 min of cold incubation in UW solution. When the endothelial cells were incubated in cold Krebs–Henseleit buffer or in cold cell culture medium instead of UW solution, similar early decreases in cellular sodium and chloride contents were observed, thus excluding the possibility of the decreases being dependent on the preservation solution used. Furthermore, experiments with cultured rat hepatocytes yielded a similar decrease in sodium content during initiation of cold incubation in UW solution, so the decrease does not appear to be cell-specific either. These results suggest that, contrary to current opinion, sodium efflux predominates over sodium influx during the early phase of cold incubation of cells.

Water and Sodium Turnover in Coastal and Inlnad Populations of the Ash-Grey Mouse, in Western Austrlia

1981 ◽  
Vol 29 (4) ◽  
pp. 519 ◽  
Author(s):  
KD Morris ◽  
SD Bradshaw
Keyword(s):  
Urine Osmolality ◽  
Sampling Period ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Turnover Rates ◽  
Coastal Habitat ◽  
Sodium Influx ◽  
Sodium Efflux ◽  
Water Influx ◽  
Water Efflux

The water and sodium turnovers of a coastal and an inland population of P. albocinereus were studied seasonally. Although the inland habitat receives considerably less rain and sodium than the coastal habitat, water turnover rates were significantly lower only in May and sodium turnover lower only in August. Water influx rates were lowest at both locations during the summer months, positively correlated with the water content of the vegetation and positively correlated with the amount of rain received in the 30 days before each sampling period. Water efflux rates were negatively correlated with urine osmolality. Sodium influx rates were highest during the summer months and were correlated with the sodium content of the vegetation but not with the sodium deposited in the study areas. Sodium efflux rates were positively correlated with the urine sodium concentration. During the dry months, water and sodium influxes are linked; this is not apparent during the wetter months. The utilization of arthropods for food during the summer months is seen as contributing to the maintenance of water balance during a period when the vegetation is low in water. Both populations breed in late spring, with young animals growing during the summer months, and water and sodium influx rates exceed efflux rates during this period.

The change from symmetry to asymmetry of a sodium transport system in red cell membranes

1985 ◽  
Vol 223 (1233) ◽  
pp. 449-457 ◽  
Keyword(s):  
Sodium Concentration ◽  
Tracer Studies ◽  
Chloride Medium ◽  
Sodium Influx ◽  
Nitrate Medium ◽  
Sodium Efflux ◽  
External Potassium ◽  
Red Cell Membranes ◽  
Stimulation Of ◽  
Human Red Cells

A study has been made with human red cells of sodium movements that are sensitive to the drug furosemide. The aim was to see if furosemide-sensitive movements that are symmetrical (exchange) became asymmetrical (net transport) on replacement of chloride with nitrate as the major external anion. Cells were incubated for 4 h at 37 °C with 140 mm sodium, and chloride or nitrate as the principal anion. Under a variety of conditions (presence and absence of ouabain or furosemide, or both) the cell sodium concentration was always higher when chloride was replaced with nitrate. The cells became leakier to sodium. Tracer studies indicated that, in contrast to the results in chloride medium, the decrease in sodium influx was greater than the fall in efflux when furosemide was added to cells in nitrate medium. The results confirm that the sensitivity of sodium efflux to furosemide depended on chloride. However, influx showed a different sensitivity in that furosemide still inhibited in cells incubated in nitrate medium. The stimulation of sodium influx with nitrate medium was independent of external potassium (10–50 mm) and the furosemide-sensitive influx was also constant. It is concluded that symmetrical transmembrane sodium movements with cells in chloride medium became downhill asymmetrical in nitrate medium, giving a net gain of cell sodium that was insensitive to ouabain and sensitive to furosemide. The drug thus partly retarded the gain of cell sodium that otherwise occurred in the somewhat leaky cells.

Effect of Zinc on Leucocyte Sodium Transport In Vitro

1978 ◽  
Vol 54 (5) ◽  
pp. 585-587 ◽  
Author(s):  
J. Patrick ◽  
J. Michael ◽  
M. N. Golden ◽  
B. E. Golden ◽  
P. J. Hilton
Keyword(s):  
Tissue Culture ◽  
Sodium Transport ◽  
Zinc Concentration ◽  
Culture Fluid ◽  
Sodium Content ◽  
Cell Water ◽  
Sodium Influx ◽  
Sodium Efflux

1. In a preparation of human leucocytes maintained in tissue culture fluid, increasing the extracellular zinc concentration leads to a significant increase in both ouabain-sensitive sodium efflux and in sodium influx. 2. Cell water and sodium content do not alter significantly with increasing extracellular zinc concentration. 3. A small increase in the ouabain-insensitive sodium efflux can be demonstrated when the external zinc concentration is raised from 0·75 μmol/l to 90 μmol/l.

scholarly journals The Effect of External Sodium and Calcium Concentrations on Sodium Fluxes by Salt-Depleted and Non-Depleted Minnows, Phoxinus Phoxinus (L.)

1987 ◽  
Vol 131 (1) ◽  
pp. 417-425
Author(s):  
W. J. FRAIN
Keyword(s):  
Sodium Concentration ◽  
Uptake Mechanism ◽  
Sodium Influx ◽  
Sodium Efflux ◽  
Sodium Uptake ◽  
Km Value ◽  
Concentration Changes ◽  
The Relationship ◽  
Very High ◽  
External Calcium

The relationship between sodium influx and external sodium concentration in Phoxinus is complex and unusual. In non-depleted fish the relationship is approximately that given by the Michaelis-Menten equation of enzyme kinetics. However, the Km value (a measure of the affinity of the sodium uptake mechanism for sodium) is very high (3mmoll−1), indicating a low affinity of the uptake mechanism for sodium. On sodium depletion, the relationship between sodium influx and external sodium concentration changes to produce a curve which has a stepped appearance, and is unusual in that the maximum influx is not increased above that in non-depleted fish. The overall Km alters very little; however, the Km for the lower part of the curve is very low (0.05 mmoll−1). A model is proposed to explain these results in the form of two sodium uptake mechanisms working in parallel across the gill. The second carrier is only active when the fish is sodium-depleted and kept in low external sodium concentrations. Neither the external sodium concentration nor the external calcium concentration has any direct effect on sodium efflux. However, fish depleted in 1 mmoll−1 calcium have a lower sodium efflux than fish depleted in distilled water. Calcium appears to reduce the permeability of the gill to ions such as sodium. Since calcium has no effect on sodium influx, changes in gill permeability do not involve the sodium influxmechanism.

scholarly journals Sodium Movements in Perfused Squid Giant Axons

1968 ◽  
Vol 52 (2) ◽  
pp. 240-257 ◽  
Author(s):  
Eduardo Rojas ◽  
Mitzy Canessa-Fischer
Keyword(s):  
Action Potential ◽  
Sodium Concentration ◽  
Dosidicus Gigas ◽  
Sodium Influx ◽  
Sodium Efflux ◽  
Inward Current ◽  
Giant Axons ◽  
Impulse Propagation ◽  
Internal Concentration

Sodium movements in internally perfused giant axons from the squid Dosidicus gigas were studied with varying internal sodium concentrations and with fluoride as the internal anion. It was found that as the internal concentration of sodium was increased from 2 to 200 mM the resting sodium efflux increased from 0.09 to 34.0 pmoles/cm2sec and the average resting sodium influx increased from 42.9 to 64.5 pmoles/cm2sec but this last change was not statistically significant. When perfusing with a mixture of 500 mM K glutamate and 100 mM Na glutamate the resting efflux was 10 ± 3 pmoles/cm2sec and 41 ± 10 pmoles/cm2sec for sodium influx. Increasing the internal sodium concentration also increased both the extra influx and the extra efflux of sodium due to impulse propagation. At any given internal sodium concentration the net extra influx was about 5 pmoles/cm2impulse. This finding supports the notion that the inward current generated in a propagated action potential can be completely accounted for by movements of sodium.

Subcellular distribution of chelatable iron: a laser scanning microscopic study in isolated hepatocytes and liver endothelial cells

2001 ◽  
Vol 356 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Frank PETRAT ◽  
Herbert de GROOT ◽  
Ursula RAUEN
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Subcellular Distribution ◽  
Laser Scanning ◽  
Rat Hepatocytes ◽  
Laser Scanning Microscopy ◽  
Isolated Rat Hepatocytes ◽  
Intact Cells ◽  
Liver Endothelial Cells ◽  
Isolated Rat

The pool of cellular chelatable iron (‘free iron’, ‘low-molecular-weight iron’, the ‘labile iron pool’) is usually considered to reside mainly within the cytosol. For the present study we adapted our previously established Phen Green method, based on quantitative laser scanning microscopy, to examine the subcellular distribution of chelatable iron in single intact cells for the first time. These measurements, performed in isolated rat hepatocytes and rat liver endothelial cells, showed considerable concentrations of chelatable iron, not only in the cytosol but also in several other subcellular compartments. In isolated rat hepatocytes we determined a chelatable iron concentration of 5.8±2.6μM within the cytosol and of at least 4.8μM in mitochondria. The hepatocellular nucleus contained chelatable iron at the surprisingly high concentration of 6.6±2.9μM. In rat liver endothelial cells, the concentration of chelatable iron within all these compartments was even higher (cytosol, 7.3±2.6μM; nucleus, 11.8±3.9μM; mitochondria, 9.2±2.7μM); in addition, chelatable iron (approx. 16±4μM) was detected in a small subpopulation of the endosomal/lysosomal apparatus. Hence there is an uneven distribution of subcellular chelatable iron, a fact that is important to consider for (patho)physiological processes and that also has implications for the use of iron chelators to inhibit oxidative stress.

The Effect of Some Anions and Cations Upon the Fluxes and Net Uptake of Sodium in the Larva of Aedes Aegypti (L)

1965 ◽  
Vol 42 (1) ◽  
pp. 29-43 ◽  
Author(s):  
R. H. STOBBART
Keyword(s):  
Sodium Concentration ◽  
Sodium Content ◽  
Deionized Water ◽  
Sodium Balance ◽  
Sodium Influx ◽  
Sodium Uptake ◽  
Chloride Uptake ◽  
Net Uptake ◽  
The Relationship ◽  
Anal Papillae

1. Starved 4th-instar larvae of Aädes aegypti, when put into deionized water at a density of ten larvae/20 ml., are able to achieve sodium balance at the low external concentration of 5µM Na/l. 2. The balancing process involves a 10% drop in total sodium content, a more or less complete activation of the mechanism for sodium transport, and a reduction in the permeability of the larva to sodium as measured by the net sodium loss into deionized water. It is very probable that most of this reduction occurs in the anal papillae. 3. The relationship between external sodium concentration and sodium influx in larvae previously ‘balanced’ in deionized water is described approximately by the Michaelis equation. The sodium outflux also increases with increasing external sodium concentrations. 4. The net uptake of sodium by ‘balanced larvae’ appears to be significantly greater from solutions of NaCl than from solutions of NaNO3 NaHCO3 and Na2SO4. 5. The ions K+ Ca++ Mg++ and NH4+ when present as chlorides stimulate the influx of sodium from 0.1 mM/l. sodium chloride. When present as nitrates or sulphates they either have no effect or cause an inhibition of influx. 6. The results in 4 and 5 suggest that movements of chloride may be important in sodium uptake, and chloride uptake has been found to occur independently of sodium uptake. Measurements of potential difference between haemolymph and medium demonstrate active transport of both sodium and chloride.

The Effects of Chronic Hypokalaemia, Hyponatraemia, and Acid-Base Alterations on Erythrocyte Sodium Transport

1972 ◽  
Vol 43 (2) ◽  
pp. 251-263 ◽  
Author(s):  
M. L. Levin ◽  
F. C. Rector ◽  
D. W. Seldin
Keyword(s):  
Active Transport ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Acid Base ◽  
Large Component ◽  
Sodium Influx ◽  
Membrane Function ◽  
Disease States ◽  
Erythrocyte Sodium

1. Erythrocyte sodium concentration and fluxes were measured in patients with acid-base disturbances, hypokalaemia and hyponatraemia. Results were similar to those obtained with normal erythrocytes exposed to artificial in vitro alterations. 2. Erythrocyte sodium content and influx varied directly with extracellular bicarbonate which appeared to influence membrane permeability. 3. Hypokalaemia increased the erythrocyte sodium content by decreasing active transport initially. When a new high erythrocyte steady-state sodium concentration was reached, active transport returned to normal but efflux and influx were increased considerably by the appearance of a large component of exchange diffusion in the hypokalaemic environment. 4. Hyponatraemia induced a decrease in sodium influx secondary to the decreased transmembrane sodium concentration gradient. A decrease in erythrocyte sodium content then ensued. 5. The results are discussed in relation to the assessment of cell membrane function in disease states.

scholarly journals The Dual Effect of Lithium Ions on Sodium Efflux in Skeletal Muscle

1968 ◽  
Vol 52 (3) ◽  
pp. 408-423 ◽  
Author(s):  
L. A. Beaugé ◽  
R. A. Sjodin
Keyword(s):  
Skeletal Muscle ◽  
Muscle Cells ◽  
Sodium Concentration ◽  
Ringer Solution ◽  
Sodium Content ◽  
Sartorius Muscle ◽  
Lithium Ions ◽  
Sodium Efflux ◽  
Ringer’S Solution ◽  
Equivalent Quantity

Sartorius muscle cells from the frog were stored in a K-free Ringer solution at 3°C until their average sodium contents rose to around 23 mM/kg fiber (about 40 mM/liter fiber water). Such muscles, when placed in Ringer's solution containing 60 mM LiCl and 50 mM NaCl at 20°C, extruded 9.8 mM/kg of sodium and gained an equivalent quantity of lithium in a 2 hr period. The presence of 10-5 M strophanthidin in the 60 mM LiCl/50 mM NaCl Ringer solution prevented the net extrusion of sodium from the muscles. Lithium ions were found to enter muscles with a lowered internal sodium concentration at a rate about half that for entry into sodium-enriched muscles. When sodium-enriched muscles labeled with radioactive sodium ions were transferred from Ringer's solution to a sodium-free lithium-substituted Ringer solution, an increase in the rate of tracer sodium output was observed. When the lithium-substituted Ringer solution contained 10-5 M strophanthidin, a large decrease in the rate of tracer sodium output was observed upon transferring labeled sodium-enriched muscles from Ringer's solution to the sodium-free medium. It is concluded that lithium ions have a direct stimulating action on the sodium pump in skeletal muscle cells and that a significantly large external sodium-dependent component of sodium efflux is present in muscles with an elevated sodium content. In the sodium-rich muscles, about 23% of the total sodium efflux was due to strophanthidin-insensitive Na-for-Na interchange, about 67% being due to strophanthidin-sensitive sodium pumping.

New physiologically-relevant liver tissue model based on hierarchically cocultured primary rat hepatocytes with liver endothelial cells

2015 ◽  
Vol 7 (11) ◽  
pp. 1412-1422 ◽  
Author(s):  
Wenjin Xiao ◽  
Guillaume Perry ◽  
Kikuo Komori ◽  
Yasuyuki Sakai
Keyword(s):  
Endothelial Cells ◽  
Liver Tissue ◽  
Human Liver ◽  
Rat Hepatocytes ◽  
Pdms Membrane ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells ◽  
Tissue Model ◽  
Primary Rat Hepatocytes ◽  
Liver Endothelial Cells

We established a physiologically-relevant liver tissue model hierarchically consisting of two complete layers of primary rat hepatocytes and human liver sinusoidal endothelial cells (TMNK-1) on an oxygen-permeable polydimethylsiloxane (PDMS) membrane.

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