Sodium exchange and net movement in rat uteri at 25 °C

1970 ◽  
Vol 48 (9) ◽  
pp. 598-624 ◽  
Author(s):  
E. E. Daniel ◽  
Kathleen Robinson
Keyword(s):  
Diffusion Coefficient ◽  
Time Course ◽  
Sodium Content ◽  
Free Solution ◽  
Electrochemical Gradient ◽  
Efflux Rate ◽  
Fresh Tissue ◽  
Sodium Efflux ◽  
Na Efflux ◽  
Wet Weight

Sodium fluxes in fresh and Na-rich uterine horns were studied. The change in efflux rate was compared with that in a theoretical model and analyzed by a curve-peeling technique. In both fresh and Na-rich tissues, the time course of efflux could be described by the sum of three exponentials. There was also a nearly inexchangeable ('bound') fraction of labelled sodium and a fraction of unlabelled sodium. Analysis of efflux led to the following equations:[Formula: see text]for fresh tissue, and[Formula: see text]for Na-rich tissues, where Y = tissue 22Na in millimoles per kilogram. The unlabelled part of the 'bound' Na amounted to 4 to 6 mmoles/kg in fresh and 6 to 8 mmoles/kg in Na-rich tissues. The amounts of 22Na in cells were calculated to be 7 and 34 mmoles/kg wet weight in fresh and Na-rich tissues. One phase of influx was similar to the fastest fraction of efflux and had a diffusion coefficient which was consistent with diffusion in the extracellular space (1/10 of that in free solution). The sodium content of this compartment was somewhat greater than sodium in the 14C-sucrose spaces (430 and 480 ml/kg in fresh and Na-rich tissue respectively). The second fastest sodium fraction (observed during efflux) was much larger in Na-rich tissues, and evidence that it contained cellular sodium was presented. Sodium efflux from cells was 5.9 pmoles cm−2 s−1 for fresh tissues and 26 pmoles cm−2 s−1 for Na-rich tissues. Comparable but less accurate values for influx were 4.2 and 7.0 pmoles cm−2 s−1. Assuming all emerging sodium was pumped against the electrochemical gradient, the energy expenditure would be 0.11 kcal/kg per h in fresh tissue and 0.22 kcal/kg per h in Na-rich tissues. It was concluded that this kind of active transport provides an unsatisfactory explanation for 22Na efflux.

scholarly journals The Time Course of the Loss and Recovery of Contracture Ability in Frog Striated Muscle Following Exposure to Ca-Free Solutions

1965 ◽  
Vol 48 (5) ◽  
pp. 841-858 ◽  
Author(s):  
J. V. Milligan
Keyword(s):  
Diffusion Coefficient ◽  
Calcium Ion ◽  
Time Course ◽  
Striated Muscle ◽  
Potassium Concentration ◽  
Ion Concentration ◽  
Bathing Solution ◽  
Free Solution ◽  
K Concentration ◽  
Calcium Ion Concentration

Using area under the contracture curve to quantitate contractures, the diffusion coefficient of calcium ions within the frog toe muscle during washout in a calcium-free solution and subsequent recovery after reintroduction of calcium to the bathing solution was calculated to be about 2 x 10-6 cm2/sec. The diffusion coefficient measured during washout was found to be independent of temperature or initial calcium ion concentration. During recovery it was found to decrease if the temperature was lowered. This was likely due to the repolarization occurring after the depolarizing effect of the calcium-free solution. The relation between contracture area and [Ca]o was found to be useful over a wider range than that between maximum tension and [Ca]o. The normalized contracture areas were larger at lower calcium concentrations if the contractures were produced with cold potassium solutions or if NO3 replaced Cl in the bathing solutions. Decreasing the potassium concentration of the contracture solution to 50 mM from 115 mM did not change the relation between [Ca]o and the normalized area. If the K concentration of the bathing solution was increased, the areas were decreased at lower concentrations of Ca.

The influence of "nonmyoplasmic" sodium on the measured value of the sodium efflux from barnacle muscle

1981 ◽  
Vol 59 (12) ◽  
pp. 1219-1227 ◽  
Author(s):  
M. R. Menard ◽  
J. A. M. Hinke
Keyword(s):  
Extracellular Space ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Sodium Content ◽  
Flame Photometry ◽  
Free Solution ◽  
Sodium Efflux ◽  
Barnacle Muscle ◽  
Total Sodium

In single striated muscle cells of the giant barnacle Balanus nubilus, the sodium content of the myoplasm was measured with an intracellular microelectrode, and the total sodium content of the cell was measured by flame photometry, during immersion of the cells in sodium-free solution. The sodium content of the myoplasm declined slowly but steadily from ca. 10 mmol/kg water to ca. 4 mmol/kg water during immersions lasting up to 16 h. The "nonmyoplasmic" sodium content of the cells, defined as the sodium content after subtraction of the sodium in the extracellular (sorbitol) space and in the myoplasm, declined rapidly from ca. 15 mmol/kg water to ca. 3 mmol/kg water during the first 30 min of immersion in sodium-free solution, but remained constant thereafter. The rapidly lost portion of the nonmyoplasmic sodium (ca. 12 mmol/kg water) was ascribed to the extracellular space but the location of the inexchangeable portion was not discovered. The behavior of the efflux of 22Na which was loaded into the myoplasm by microinjection was consistent with this interpretation. It was concluded that the nonmyoplasmic sodium does not have an appreciable influence on the measured value of the sodium efflux from the myoplasm of barnacle muscle cells.

A Study In Vitro of the Sodium Pump in Fulminant Hepatic Failure

1978 ◽  
Vol 55 (4) ◽  
pp. 355-363 ◽  
Author(s):  
A. N. Alam ◽  
Lucilla Poston ◽  
S. P. Wilkinson ◽  
C. G. Golindano ◽  
R. Williams
Keyword(s):  
Fulminant Hepatic Failure ◽  
Hepatic Failure ◽  
Sodium Pump ◽  
Normal Subjects ◽  
Sodium Content ◽  
Atp Content ◽  
Efflux Rate ◽  
Sodium Efflux ◽  
Reduced Activity

1. The mechanism underlying the raised leucocyte sodium content in fulminant hepatic failure was studied by measurement of sodium fluxes, (Na+ + K+)-dependent adenosine triphosphatase activity, and leucocyte ATP content. 2. The rate constant for sodium efflux in the leucocytes was significantly reduced, and attributable to reduced activity of the enzyme (Na+ + K+)-ATPase. Leucocyte ATP content was not significantly different from that of control cells. 3. Incubation of cells from patients in the sera of normal subjects resulted in a reversal of these changes. Inhibition of the leucocyte sodium efflux rate constants and (Na+ + K+)-ATPase of normal cells was achieved by incubation in sera from patients. 4. We suggest that the raised sodium content of leucocytes in fulminant hepatic failure is attributable to a defective sodium pumping mechanism, possibly due to a circulating toxin.

Effect of Hypokalaemia on the Ouabain-Sensitive Sodium Transport and the Ouabain-Binding Capacity in Human Erythrocytes

1983 ◽  
Vol 64 (2) ◽  
pp. 177-182 ◽  
Author(s):  
E. Jill Rubython ◽  
D. B. Morgan
Keyword(s):  
Rate Constant ◽  
Binding Capacity ◽  
Plasma Potassium ◽  
Inhibitory Effect ◽  
Sodium Content ◽  
Efflux Rate ◽  
Ouabain Binding ◽  
Sodium Efflux ◽  
Sodium Pumps ◽  
Efflux Rate Constant

1. The sodium content, the ouabain-sensitive sodium efflux and efflux rate constant and the ouabain-binding capacity were measured in the erythrocytes of 53 patients with hypokalaemia and in 37 healthy controls. The sodium content alone was measured in a further 57 patients with hypokalaemia. 2. In the patients with hypokalaemia there was an increase in the average sodium content of the erythrocytes, which was entirely due to a reduction in the ouabain-sensitive efflux rate constant. 3. The ratio of the ouabain-sensitive efflux rate constant to the number of sodium pumps was decreased in the patients with hypokalaemia, and was directly related to the plasma potassium. 4. Many patients with moderate hypokalaemia had normal erythrocyte sodium and potassium contents and normal ouabain-sensitive efflux rate constant. These patients had an increased number of sodium pumps, which compensated for the inhibitory effect of hypokalaemia on each sodium pump. 5. This increase in the number of sodium pumps was common even in patients who had probably had hypokalaemia for less than 2 weeks. This finding suggests that there are latent sodium pumps within the circulating erythrocytes.

The Relation between Membrane Cholesterol and Phospholipid and Sodium Efflux in Erythrocytes from Healthy Subjects and Patients with Chronic Cholestasis

1982 ◽  
Vol 62 (1) ◽  
pp. 101-107 ◽  
Author(s):  
P. A. Jackson ◽  
D. B. Morgan
Keyword(s):  
Rate Constant ◽  
Healthy Subjects ◽  
Sodium Content ◽  
Molar Ratio ◽  
Phospholipid Content ◽  
Efflux Rate ◽  
Sodium Efflux ◽  
Chronic Cholestasis ◽  
Efflux Rate Constant ◽  
Erythrocyte Sodium

1. The cholesterol and phospholipid content of the cell membrane and the efflux of sodium were measured in the erythrocytes of patients with chronic cholestasis and in healthy subjects. 2. The membranes from the patients contained more cholesterol and phospholipid and had a higher cholesterol/phospholipid molar ratio than the membranes from the healthy subjects. 3. The sodium efflux rate constant was reduced in the patients and this was entirely due to a reduction in the frusemide-sensitive efflux rate constant. There was no difference in either the ouabain-sensitive or the ouabain plus frusemide-resistant rate constants. 4. This reduction in the frusemide-sensitive rate constant was associated with a reduction in the erythrocyte sodium content. 5. When erythrocytes were loaded with cholesterol in vitro the frusemide-sensitive efflux rate constant was reduced by an amount similar to that observed in the patients. In addition, however, there was a reduction in the ouabain-sensitive efflux rate constant and an increase in the erythrocyte sodium content; neither of these changes was observed in the patients in vivo.

scholarly journals The effect of Intralipid® infusion on the human leucocyte sodium-pump in vivo

1988 ◽  
Vol 60 (1) ◽  
pp. 49-55 ◽  
Author(s):  
L. L. Ng ◽  
T. D. R. Hockaday
Keyword(s):  
Rate Constants ◽  
Sodium Pump ◽  
Dry Weight ◽  
Sodium Content ◽  
Normal Weight ◽  
Efflux Rate ◽  
Heparin Infusion ◽  
Na Efflux ◽  
Nefa Level

1. The effect of unsaturated long-chain non-esterified fatty acids (NEFA) on the human leucocyte sodium-pump was studied in vivo.2. Plasma NEFA level was raised acutely from 0·28 (sd 0·10) to 2·54 (sd 0·48) mmol/l by infusion of ‘Intralipid 20%’ (trademark) at 90 ml/h with heparin, and the human leucocyte 22Na efflux rate constants were studied in eight normal weight males.3. After 3 h, there was a significant lowering of the total (from 3·97 (sd 0·92) to 3·10 (sd 0·71)/h; P < 0·01) and ouabain-sensitive 22Na efflux rate constants (from 2·89 (sd 0·55) to 2·37 (sd 0·62)/h; P < 0·02). Ouabain-insensitive efflux rate constants showed a tendency to fall (from 1·08 (sd 0·51) to 0·73 (sd 0·23)/h). Leucocyte potassium content remained unchanged, but sodium content rose from 31 (sd 12) to 38 (sd 18) mmol/kg dry weight (P < 0·05). Total, ouabain-insensitive and ouabain-sensitive efflux rates did not change significantly during the Intralipid-heparin infusion.4. Plasma insulin levels rose gradually throughout the 3 h infusion period.5. In conclusion, NEFA, when raised to pathological levels, can inhibit the leucocyte Na-pump in vivo even in the presence of physiological levels of serum albumin, and may increase insulin secretion.

Changes in the Number and Activity of Sodium Pumps in Erythrocytes from Patients with Hyperthyroidism

1983 ◽  
Vol 64 (4) ◽  
pp. 441-447 ◽  
Author(s):  
E. Jill Rubython ◽  
M. Cumberbatch ◽  
D. B. Morgan
Keyword(s):  
Rate Constant ◽  
Binding Capacity ◽  
Zinc Content ◽  
Sodium Content ◽  
Efflux Rate ◽  
Ouabain Binding ◽  
Sodium Efflux ◽  
Sodium Pumps ◽  
Efflux Rate Constant ◽  
Hyperthyroid Patients

1. The sodium content, the rate and rate constant of ouabain-sensitive sodium efflux and the number of sodium pumps (indicated by the ouabain-binding capacity) were measured in erythrocytes from patients with hyperthyroidism and compared with values obtained in euthyroid patients and healthy control subjects. Erythrocyte zinc content was measured as a simple estimate of the content of carbonic anhydrase. 2. In the hyperthyroid patients, erythrocyte sodium content was increased, whereas the rate and rate constant of ouabain-sensitive sodium efflux, the ouabain-binding capacity and erythrocyte zinc content were all decreased. 3. The sodium pumps in hyperthyroidism had the same affinity for ouabain and the same rate constant per pump as those in healthy controls. 4. The decrease in the efflux rate constant could be entirely accounted for by the decrease in the number of sodium pumps. 5. Although the sodium efflux was decreased in the hyperthyroid patients, the change was less than expected for the decrease in the efflux rate constant. This suggests that there is an increase in the ground permeability of the erythrocyte membrane in hyperthyroidism. 6. In the hyperthyroid patients the number of sodium pumps and erythrocyte zinc content were inversely related to the plasma levels of thyroxine and tri-iodothyronine, but more closely to the latter. 7. These results suggest that the thyroid hormones may influence the erythrocyte's content of a range of proteins which happens to include the sodium pump.

Studies of Sodium Transport in Thymocytes of Rats with DOC/Salt Hypertension

1982 ◽  
Vol 63 (s8) ◽  
pp. 65s-67s ◽  
Author(s):  
R. B. Jones ◽  
J. Patrick ◽  
P. J. Hilton
Keyword(s):  
Rate Constant ◽  
Sodium Transport ◽  
Dry Weight ◽  
Sodium Content ◽  
Intracellular Sodium ◽  
Control Group ◽  
Efflux Rate ◽  
Sodium Influx ◽  
Sodium Efflux ◽  
Efflux Rate Constant

1. Sodium transport and intracellular sodium content were studied in thymocytes of rats made hypertensive by treatment for 4 or 8 weeks with deoxycorticosterone (DOC) and salt (DOC/salt). 2. The systolic blood pressure in the DOC/salt animals was 152 ± sem 3 and 189 ± 3 mmHg after 4 and 8 weeks' treatment respectively. This was significantly higher than pressures in their respective controls (124 ± 4 and 126 ± 5 mmHg), which had been given 1% sodium chloride solution (171 mmol/l) only. 3. The total sodium efflux rate constant in the DOC/salt rats was lower than that in the control group after 8 weeks of treatment (5.56 ± sem 0.21 vs 6.12 ± 0.11 h−1; P < 0.05) but not after 4 weeks of treatment (5.93 ± 0.13 vs 6.32 ± 0.13 h−1;0.1 > P > 0.05). 4. Intracellular sodium content in the DOC/salt rats was significantly higher than that of the control animals after 8 weeks' treatment (49.6 ± 2.5 vs 42.1 ± 1.0 mmol/kg dry weight; P < 0.05). 5. No significant changes were observed in intracellular potassium content, sodium influx or ouabain-insensitive sodium efflux rate constant.

Physiological Correlates of Interspecific Variation in Acid Tolerance in Fish

1988 ◽  
Vol 136 (1) ◽  
pp. 243-258 ◽  
Author(s):  
J. FREDA ◽  
D. G. MCDONALD
Keyword(s):  
Yellow Perch ◽  
Acid Tolerance ◽  
Binding Activity ◽  
Low Ph ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Survival Times ◽  
Ion Regulation ◽  
Sodium Efflux ◽  
Na Efflux

This study investigated ion regulation in relation to water pH in three species of fish of differing tolerance to low pH (common shiners, Notropis cornutus, most sensitive; rainbow trout, Salmo gairdneri, intermediate; yellow perch, Perca flavescens, least sensitive). Increasing sensitivity to exposure to low pH was characterized by shorter survival times, greater losses of whole-body ions, more complete inhibition of Na+ uptake, and greater stimulation of Na+ efflux, the latter being the most important factor in determining survival. Interspecific variations in acid tolerance were also correlated with Na+ transport characteristics at circumneutral pH; Km was directly correlated and Vmax inversely correlated with acid tolerance. In addition, there were large qualitative differences among the species in the Ca2+-dependence of Na+ efflux. Sodium efflux induced by low pH was markedly Ca2+-dependent in both trout and shiners in a manner consistent with a simple competition between Ca2+ and H+ for gill binding sites. The increased sensitivity of shiners relative to trout was related to lowered Ca2+- binding activity. In contrast, Na+ efflux in perch was virtually unaffected by water [Ca2+]. Similarly, La3+ (a Ca2+ antagonist) stimulated higher Na+ losses from shiners than from trout, but had little effect upon perch. Ionic losses produced by saturating La3+ concentrations were generally lower than those produced by H+, suggesting that Ca2+ displacement is not the only mechanism for increased gill permeability at low pH. Nonetheless, the results obtained are consistent with the notion that acid tolerance may be related to Ca2+-binding activity in some species (e.g. trout and shiners) although not in others (e.g. perch).

Sodium exchange and distribution in the arterial wall

1965 ◽  
Vol 209 (5) ◽  
pp. 955-960 ◽  
Author(s):  
P. Garrahan ◽  
M. F. Villamil ◽  
J. A. Zadunaisky
Keyword(s):  
Temperature Coefficient ◽  
Phase 1 ◽  
Compartmental Analysis ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Phase 2 ◽  
Fresh Tissue ◽  
Intracellular Sodium Concentration ◽  
Diffusion Curve ◽  
Total Sodium

Pieces of dog carotid artery were studied with respect to water and sodium content. Total sodium content averaged 113 ± 1.2 mm/kg fresh tissue; total water 73.6 ± 0.3% and inulin space 36.2 ± 0.5% of tissue wet wt. A total of 94.8 ± 1.3% of sodium exchanged within 6–12 min with Na22, and 97.4 ± 0.7% of the stable sodium was extracted in sodium-free solution (choline replacement). The curve of efflux of Na22 at 37 C could be decomposed into three simple exponentials with half-times of 42.5 ± 2.3 sec ( phase 1), 5.0 ± 0.3 min ( phase 2), and 71.0 ± 7.3 min ( phase 3). Exchange of sodium of phase 1 (extracellular) fitted well with a theoretical diffusion curve, showed low temperature coefficient and no potassium dependency, and was not influenced by ouabain. Exchange of sodium of phase 2 (cellular) showed high temperature coefficient and potassium dependency and was sensitive to ouabain. Calculations based on the compartmental analysis indicate a too-great intracellular sodium concentration. Binding of sodium to polyanions in the extracellular space is suggested as a possible explanation of the results.

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