The Effect of External Potassium Concentration on Leucocyte Cation Transport in Vitro

1975 ◽  
Vol 49 (5) ◽  
pp. 385-390
Author(s):  
P. J. Hilton ◽  
R. P. S. Edmondson ◽  
R. D. Thomas ◽  
J. Patrick
Keyword(s):  
Potassium Concentration ◽  
Potassium Transport ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Maximum Value ◽  
External Potassium ◽  
Potassium Influx ◽  
Potassium Exchange ◽  
Sodium And Potassium

1. Sodium and potassium transport rates in human leucocytes were measured in vitro at different external potassium concentrations. 2. At nominally zero external potassium concentrations, the ouabain-sensitive sodium efflux was reduced to less than 20% of its maximum value. There was evidence that under these conditions a ouabain-sensitive sodium-sodium exchange occurs. 3. Both total and ouabain-insensitive potassium influx increased with increasing external potassium concentration. The ouabain-sensitive potassium influx showed saturation. 4. Ouabain-insensitive potassium efflux was also stimulated by increasing the external potassium concentration, suggesting significant potassium-potassium exchange at physiological external potassium concentrations.

Effect of Extracellular Potassium on the Transport of Sodium and Potassium in Rat Thymocytes

1981 ◽  
Vol 61 (3) ◽  
pp. 307-312 ◽  
Author(s):  
R. B. Jones ◽  
J. Patrick ◽  
P. J. Hilton
Keyword(s):  
Potassium Concentration ◽  
Extracellular Potassium ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Extracellular Potassium Concentration ◽  
External Potassium ◽  
Potassium Influx ◽  
Sodium And Potassium

1. The effect of extracellular potassium on the transport of sodium and potassium in rat thymocytes has been studied in vitro. 2. A significant increase in the rate constant for total and ouabain-sensitive sodium efflux was demonstrated at an extracellular potassium concentration of 1 mmol/l as compared with that at either 0 or 2 mmol/l. 3. At potassium concentrations below 3 mmol/l ouabain-sensitive sodium influx was observed suggesting sodium-sodium exchange catalysed by the sodium pump. 4. Both total and ouabain-insensitive potassium efflux rose with external potassium. A small ouabain-sensitive potassium efflux was observed at all levels of external potassium studied. 5. Total and ouabain-insensitive potassium influx increased with external potassium, but did not appear to saturate. Ouabain-sensitive potassium influx reached a maximum at an external potassium concentration of 2 mmol/l then decreased with increasing external potassium.

Frusemide-Sensitive Sodium and Potassium Transport by Human Leucocytes

1985 ◽  
Vol 68 (1) ◽  
pp. 89-91 ◽  
Author(s):  
Valerie E. Johnson ◽  
P. J. Hilton
Keyword(s):  
Potassium Transport ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Sodium Potassium ◽  
External Potassium ◽  
Normal Human ◽  
Potassium Influx ◽  
Net Flux ◽  
Sodium And Potassium

1. Frusemide-sensitive sodium and potassium transport by normal human leucocytes has been studied in vitro by both isotopic and net flux techniques. 2. In physiological media the leucocyte exhibits a frusemide-sensitive influx of sodium and potassium of equal magnitude compatible with a 1:1 co-transport system. 3. Cells exposed to zero external sodium and potassium (osmolality maintained with choline) demonstrated a frusemide-sensitive sodium and potassium efflux. 4. Frusemide-sensitive potassium influx was dependent on the presence of external sodium but frusemide-sensitive sodium influx persisted unchanged in the absence of external potassium. 5. Frusemide-sensitive potassium influx was dependent on external chloride but frusemide-sensitive sodium influx was chloride-independent. 6. These last two observations make it likely that the frusemide-sensitive pathway is capable of operating in modes other than sodium-potassium co-transport.

Sodium and Potassium Transport Rates in Normal Human Leucocytes in Hypo-Osmolal Extracellular Fluid

1974 ◽  
Vol 46 (5) ◽  
pp. 613-617 ◽  
Author(s):  
P. J. Hilton ◽  
J. Patrick
Keyword(s):  
Rate Constants ◽  
Extracellular Fluid ◽  
Dry Weight ◽  
Potassium Transport ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Normal Human ◽  
Potassium Influx ◽  
Sodium And Potassium

1. Sodium and potassium transport rates were studied in normal human leucocytes exposed to iso-osmolal and hypo-osmolal extracellular fluid. 2. Hypo-osmolality of the extracellular fluid led to an increase in sodium influx and a decrease in potassium influx expressed as mmol h−1 kg−1 cell dry weight. The fall in potassium influx was smaller than the rise in sodium influx and was confined to the ouabain-insensitive portion of the flux. 3. The rate constants for sodium and potassium efflux did not differ significantly between the iso-osmolal and hypo-osmolal media.

Sodium and Potassium Flux Rates in Normal Human Leucocytes in an Artificial Extracellular Fluid

1973 ◽  
Vol 44 (5) ◽  
pp. 439-445 ◽  
Author(s):  
P. J. Hilton ◽  
J. Patrick
Keyword(s):  
Extracellular Fluid ◽  
Dry Weight ◽  
Radioactive Isotopes ◽  
Efflux Rate ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Potassium Flux ◽  
Normal Human ◽  
Potassium Influx ◽  
Sodium And Potassium

1. Sodium and potassium efflux and influx rates were studied in normal human leucocytes in an artificial extracellular fluid using radioactive isotopes. 2. The rate constant for sodium efflux was 4.2 h−1 corresponding to a sodium efflux rate of 487 mmol kg cell dry weight−1 h−1. Approximately three-quarters of this flux was ouabain sensitive. 3. Potassium influx was 346 mmol kg cell dry weight−1 h−1. Approximately two-thirds of the potassium influx was ouabain insensitive.

Erythrocyte Sodium and Potassium in Patients with Hypokalaemia

1983 ◽  
Vol 64 (2) ◽  
pp. 167-176 ◽  
Author(s):  
M. Cumberbatch ◽  
D. B. Morgan
Keyword(s):  
Potassium Concentration ◽  
Sodium Content ◽  
Potassium Content ◽  
Extracellular Potassium ◽  
Moderate Degree ◽  
Sodium Efflux ◽  
Erythrocyte Sodium ◽  
Curvilinear Relation ◽  
Sodium And Potassium

1. The erythrocyte content of sodium and of potassium were measured in 231 unselected patients with hypokalaemia, and together with net ouabain-sensitive sodium efflux in patients with severe hypokalaemia, before (20 patients) and during potassium repletion (14 patients). 2. The erythrocytes of the patients with hypokalaemia compared with control subjects had on average an increase in sodium content, a decrease in potassium content and a reduction in the rate constant of ouabain-sensitive sodium efflux. All three changes had a similar curvilinear relation to the concentration of potassium in plasma with relatively little change in the measured variable unless the plasma potassium was very low. 3. There was a similar curvilinear relation between the final sodium and potassium content of normal erythrocytes and the potassium concentration of the medium in which they were incubated for 48 h in vitro. 4. These results suggest that the changes in the sodium and potassium content of erythrocytes in hypokalaemia are due to a direct inhibiting effect of the hypokalaemia on the activity of the sodium pump. 5. In many patients with hypokalaemia of moderate degree the increase in erythrocyte sodium content was less than expected from the effect in vitro of a low extracellular potassium concentration. This finding suggests that a compensatory change, presumably an increase in the number of sodium pumps, is a common event even in moderate hypokalaemia.

Na+ transport properties of the peritubular membrane of cortical collecting tubule

1982 ◽  
Vol 242 (6) ◽  
pp. F664-F671 ◽  
Author(s):  
E. Natke ◽  
L. C. Stoner
Keyword(s):  
Efflux Rate ◽  
Bathing Medium ◽  
Sodium Efflux ◽  
Collecting Tubule ◽  
Potassium Influx ◽  
Collecting Tubules ◽  
Low K ◽  
Sodium And Potassium ◽  
Cortical Collecting Tubule

The effects of varying endogenous aldosterone levels on the passive and active properties of the peritubular membrane were studied. Rabbits that were fed either a low Na+ (normal K+) diet or a high Na+, low K+ diet increased or decreased plasma aldosterone, respectively. Tubules were dissected, filled with oil, and incubated in 0 K+ medium to increase intracellular sodium. Cellular sodium and potassium content was measured by helium-glow photometry. The degree to which cells accumulate sodium and lose potassium is a function not only of time of exposure but also of diet. Tubules from animals on a low Na+ diet are about 6 times more permeable to sodium than those from animals fed a high Na+ diet. When tubules were loaded with sodium and returned to a normal (5 mM K+) bathing medium, net sodium efflux and potassium influx occurred. The rate of sodium efflux by cortical collecting tubules dissected from animals on the low Na+ diet was 2.3 times greater than the efflux rate of tubules from animals on the high Na+ diet. These data suggest that high levels of endogenous aldosterone enhance sodium transport measured in vitro across the peritubular membrane of cortical collecting tubule.

Electrophysiological analysis of potassium and sodium movements in crustacean nervous system

1975 ◽  
Vol 63 (1) ◽  
pp. 85-115
Author(s):  
N. J. Abbott ◽  
R. B. Moreton ◽  
Y. Pichon
Keyword(s):  
Nervous System ◽  
Peripheral Nerve ◽  
Model System ◽  
Diffusion Barriers ◽  
Ion Pump ◽  
Half Time ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Electrophysiological Method ◽  
Sodium And Potassium

1. An electrophysiological method was used to estimate the half-times for sodium and potassium entry to, and efflux from, the extra-axonal space in peripheral nerve and central nervous connectives of two species of crustacean. Results from crab (marine) and crayfish (fresh water) were qualitatively similar. 2. Peripheral nerve showed no evidence for diffusion barriers, potassium entry and efflux being rapid, and proceeding at comparable rates. 3. In connective, potassium entry was extremely slow, with a half-time greater than 100 min, while potassium efflux was relatively rapid (T 1/2 = 6 min). Sodium movements were less restricted, but sodium entry was more rapid than sodium efflux. 4. The potassium experiments were compared with the behaviour of a theoretical model system. Evidence is presented for diffusional restriction to potassium at the connective perineurial layer. The mechanism of restriction may involve changes in permeability or activation of an ion pump in the perineurial layer. 5. The physiological significance of these findings is discussed.

The Effect of External Potassium Ions on the Electrical Potential Measured Across the Gills of the Teleost, Dormitator Maculatus

1974 ◽  
Vol 61 (2) ◽  
pp. 277-283
Author(s):  
DAVID H. EVANS ◽  
JEFFREY C. CARRIER ◽  
MARGARET B. BOGAN
Keyword(s):  
Sea Water ◽  
Electrical Potential ◽  
Potassium Ions ◽  
Sodium Efflux ◽  
Electrical Potentials ◽  
External Potassium ◽  
Potassium Influx ◽  
Sodium Extrusion ◽  
Sufficient Magnitude ◽  
Stimulation Of

1. A technique has been developed for the measurement of electrical potentials (TGP's) across the gills of free-swimming, Dormitator maculatus. 2. Transfer of fish to various KCl solutions is correlated with changes in the TGP, which are not of sufficient magnitude to account for the known potassium stimulation of sodium efflux from this species. 3. Transfer to potassium-free sea water results in little or no change in TGP while previous results have shown that such a transfer is correlated with a 22% reduction of sodium efflux. 4. Transfer to fresh water results in a reduction of TGP from +17 mV (inside positive) to -36 mV which is sufficient to account for the instantaneous reduction in sodium efflux previously shown for this species. 5. It is concluded that while changes in TGP can account for the ‘Na-free effect’ in D. maculatus they cannot account for the potassium effects on sodium extrusion. This supports the previous conclusion that sodium efflux and potassium influx are chemically linked in this species.

THE EFFECT OF MUSCULAR EXERCISE ON PLASMA SODIUM AND POTASSIUM IN THE RAT

1958 ◽  
Vol 36 (3) ◽  
pp. 333-338 ◽  
Author(s):  
F. A. Sréter ◽  
Sydney M. Friedman
Keyword(s):  
Potassium Concentration ◽  
Plasma Potassium ◽  
Sodium Concentration ◽  
Plasma Sodium ◽  
Preliminary Training ◽  
Plasma Sodium Concentration ◽  
Rate Of Increase ◽  
Response To Exercise ◽  
Sodium And Potassium

After running a distance of 100 meters in 7 minutes, untrained rats showed a rise in plasma potassium and a fall in plasma sodium as measured in tail vein samples. These changes are in accord with in vitro observations of the effects of exercise on isolated muscle preparations and similarly are taken to indicate a gain of sodium and a loss of potassium by the exercised muscles in the whole animal. Within 10 minutes of completion of the exercise, plasma sodium concentration was restored to normal while potassium was restored within 20 minutes. Exercise was accompanied by a fall in haematocrit, which remained low for up to 40 minutes. A period of 2 months of preliminary training modified the response to exercise. In these trained animals, a fall in sodium concentration occurred as before but the rise in potassium concentration was less in degree and the haematocrit did not change. It is suggested that the rate of increase of plasma potassium is an index of muscle efficiency while the height of plasma potassium is correlated with the fatigue limit of exercise.

Direct Effects of Adrenal Cortical Steroids on the Electrolyte Content of Rabbit Leucocytes

1957 ◽  
Vol 190 (1) ◽  
pp. 104-108 ◽  
Author(s):  
D. Laurence Wilson
Keyword(s):  
Potassium Concentration ◽  
Sodium Concentration ◽  
Intracellular Sodium ◽  
Chemical Analyses ◽  
Direct Effects ◽  
Absolute Change ◽  
Sodium And Potassium ◽  
Intracellular Potassium Concentration ◽  
Reciprocal Change

Viable rabbit leucocytes have been obtained in quantities sufficient to permit direct chemical analyses of intracellular sodium and potassium concentrations. Treatment in vitro either with cortisone (10 or 20 mg/l.) or with desoxycorticosterone glycoside (10–80 mg/l.) led to a fall in intracellular potassium concentration and a reciprocal rise in intracellular sodium. There was an associated rise in intracellular water. After cortisone, the absolute change in sodium concentration slightly exceeded the reciprocal change in potassium; after desoxycorticosterone glycoside, the reverse was true.

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