Sodium Extrusion by a Fish Acclimated to Sea Water: Physiological and Biochemical Description of a Na-FOR-K Exchange System

1973 ◽  
Vol 58 (3) ◽  
pp. 627-636
Author(s):  
DAVID H. EVANS ◽  
CHARLES H. MALLERY ◽  
LARRY KRAVITZ
Keyword(s):  
Sea Water ◽  
Gill Tissue ◽  
Enzymic Activity ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Sodium Efflux ◽  
Biochemical Assays ◽  
External Potassium ◽  
Sodium Extrusion

1. The effect of external potassium ions on the extrusion of sodium ions by the seawater-acclimated fat sleeper, Dormitator maculatus, was investigated. 2. Removal of external potassium ions reduced the efflux of sodium from the fish by 22% while addition of 10-4 M ouabain reduced the efflux of sodium ions by 14%. 3. Addition of potassium ions to distilled-water baths into which fish were rapidly transferred stimulated sodium extrusion in a manner which could be described by the Michaelis-Menten equation. The Km of this potassium-stimulated sodium efflux was approximately 2 mM-K/1. 4. The calculated rate of sodium extrusion was 10 times the oral ingestion of sodium ions. 5. Biochemical assays of the levels of the enzyme Na-K-activated ATPase extracted from gill tissue determined that seawater-acclimated fish had 3 times the enzymic activity that fish acclimated to freshwater had. 6. In vitro potassium stimulation of the extracted Na-K-activated ATPase showed Michaelis-Menten kinetics with a Km of approximately 2 mM-K/l. 7. It is concluded that the extrusion of sodium ions by Dormitator maculatus acclimated to sea water is coupled with potassium uptake and is mediated by the enzyme Na-K-activated ATPase.

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.

scholarly journals The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations

1971 ◽  
Vol 57 (2) ◽  
pp. 164-187 ◽  
Author(s):  
R. A. Sjodin
Keyword(s):  
Sodium Ion ◽  
Ion Concentration ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Sodium Efflux ◽  
Sodium Dependent ◽  
Na Efflux ◽  
External Potassium ◽  
Sodium Extrusion ◽  
Sodium And Potassium

After a 20 min initial washout, the rate of loss of radioactively labeled sodium ions from sodium-enriched muscle cells is sensitive to the external sodium and potassium ion concentrations. In the absence of external potassium ions, the presence of external sodium ions increases the sodium efflux. In the presence of external potassium ions, the presence of external sodium ions decreases the sodium efflux. In the absence of external potassium ions about one-third of the Na+ efflux that depends upon the external sodium ion concentration can be abolished by 10-5 M glycoside. The glycoside-insensitive but external sodium-dependent Na+ efflux is uninfluenced by external potassium ions. In the absence of both external sodium and potassium ions the sodium efflux is relatively insensitive to the presence of 10-5 M glycoside. The maximal external sodium-dependent sodium efflux in the absence of external potassium ions is about 20% of the magnitude of the maximal potassium-dependent sodium efflux. The magnitude of the glycoside-sensitive sodium efflux in K-free Ringer solution is less than 10% of that observed when sodium efflux is maximally activated by potassium ions. The inhibition of the potassium-activated sodium efflux by external sodium ions is of the competitive type. Reducing the external sodium ion concentration displaces the plots of sodium extrusion rate vs. [K]o to the left and upwards.

scholarly journals The Influence of Potassium- and Sodium-Free Solutions on Sodium Efflux from Squid Giant Axons

1969 ◽  
Vol 54 (5) ◽  
pp. 664-674 ◽  
Author(s):  
R. A. Sjodin ◽  
L. A. Beauge
Keyword(s):  
External Solution ◽  
Potassium Ions ◽  
Small Decrease ◽  
Sodium Ions ◽  
Lithium Ions ◽  
Sodium Efflux ◽  
Giant Axons ◽  
External Potassium

The sensitivity of sodium efflux to the removal of potassium ions from the external solution and the change in sodium efflux occurring when sodium ions are also removed were observed to be related. When Tris was used to replace external sodium ions, increases in sodium efflux were always observed whether the sensitivity of sodium efflux to external potassium ions was weak or strong. Greater percentage increases in sodium efflux occurred, however, the greater the sensitivity of sodium efflux to external potassium ions. When lithium ions were used to replace external sodium ions, increases in sodium efflux occurred if the sensitivity of efflux to external potassium ions was strong whereas decreases in sodium efflux took place if the sensitivity of efflux to external potassium ions was weak. Intermediate sensitivities of efflux to external potassium resulted in no change in efflux upon substitution of lithium ions for external sodium ions. In the presence of 10-5 M ouabain, substitution of Tris for external sodium ions always resulted in a small decrease in sodium efflux. The data can be described in terms of a model which assumes the presence of efflux stimulation sites that are about 98% selective to potassium ions and about 2% selective to sodium or lithium ions.

The Movements of Sodium Ions in the Isolated Abdominal Nerve Cord of the Cockroach, Periplaneta Americana

1961 ◽  
Vol 38 (3) ◽  
pp. 629-636
Author(s):  
J. E. TREHERNE
Keyword(s):  
Nerve Cord ◽  
Periplaneta Americana ◽  
Potassium Cyanide ◽  
Ringer Solution ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Sodium Efflux ◽  
Exponential Decline ◽  
External Potassium ◽  
Nerve Cords

1. The rate of loss of sodium ions from the abdominal nerve cord of Periplaneta has been determined by following the decline in radioactivity of 24Na-loaded nerve cords isolated in flowing Ringer solution. 2. In all of the experiments there was an initial rapid exponential decline in radioactivity which eventually gave way to a second slower phase. 3. The initial exponential extrusion of sodium ions was appreciably reduced by the presence of potassium cyanide and 2:4-dinitrophenol. 4. The rate of sodium efflux was not reduced in sodium-free solutions, but was decreased in the absence of external potassium ions. 5. It is concluded that sodium ions are extruded from the nerve cord by a metabolically maintained secretory mechanism which is also associated with the uptake of potassium ions.

The energy requirement for sodium extrusion from a frog muscle

1954 ◽  
Vol 142 (908) ◽  
pp. 383-392 ◽  
Keyword(s):  
Oxygen Consumption ◽  
Energy Production ◽  
Energy Requirement ◽  
Metabolic Inhibitors ◽  
Sodium Efflux ◽  
External Potassium ◽  
Radioactive Sodium ◽  
Sodium Extrusion ◽  
Frog Sartorius ◽  
Made In

Parallel measurements have been made of the oxygen consumption and efflux of radioactive sodium in pairs of frog sartorius muscles. Calculation of the amount of secretory work necessary for an active extrusion of sodium at the observed rate showed that it would involve the utilization of about one-tenth of the energy available from resting metabolism.This figure may reasonably be regarded as a lower limit to the efficiency of the secretory mechanism. Some of the measurements were made in a potassium-free Ringer’s solution, and others with an external potassium concentration of 10mM. In the potassium-rich medium, both the sodium efflux and the oxygen consumption were increased, the proportion of the energy production required for sodium extrusion remaining roughly constant. The action of dinitrophenol and other metabolic inhibitors on the sodium efflux in sartorius muscles was examined, but there were no very obvious effects.

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.

scholarly journals On the Mechanism of Sodium Extrusion across the Irrigated Gill of Sea Water-Adapted Rainbow Trout (Salmo gairdneri)

1974 ◽  
Vol 64 (2) ◽  
pp. 148-165 ◽  
Author(s):  
Leonard B. Kirschner ◽  
Lewis Greenwald ◽  
Martin Sanders
Keyword(s):  
Rainbow Trout ◽  
Active Component ◽  
Sea Water ◽  
Salmo Gairdneri ◽  
Sodium Efflux ◽  
Exchange Diffusion ◽  
The Difference ◽  
Sodium Extrusion ◽  
Trout Gill ◽  
Electrical Data

Sodium efflux (JoutNa) across the irrigated trout gill was rapid in sea water (SW), but only about 25 % as large in fresh water (FW). The difference correlated with a change in the potential difference across the gill (TEP). The latter was about +10 mV (blood positive) in SW, but –40 mV in FW. Both flux and electrical data indicated that gills in this fish are permeable to a variety of cations including Na+, K+, Mg2+, choline, and Tris. They are less permeable to anions; PNa:PK:PCl was estimated to be 1:10:0.3, and PCl > Pgluconate. The TEP was shown to be a diffusion potential determined by these permeabilities and the extant ionic gradients in SW, FW as well as in other media. JoutNa appeared to be diffusive in all of the experiments undertaken. Exchange diffusion need not be posited, and the question of whether there is an active component remains open.

scholarly journals Catecholamine-stimulated ion transport in duck red cells. Gradient effects in electrically neutral [Na + K + 2Cl] Co-transport.

1982 ◽  
Vol 80 (1) ◽  
pp. 125-147 ◽  
Author(s):  
M Haas ◽  
W F Schmidt ◽  
T J McManus
Keyword(s):  
Membrane Potential ◽  
Red Cells ◽  
Disulfonic Acid ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Cation Permeability ◽  
External Potassium ◽  
Sodium Extrusion ◽  
Gradient Effects ◽  
Stimulation Of

The transient increase in cation permeability observed in duck red cells incubated with norepinephrine has been shown to be a linked, bidirectional, co-transport of sodium plus potassium. This pathway, sensitive to loop diuretics such as furosemide, was found to have a [Na + K] stoichiometry of 1:1 under all conditions tested. Net sodium efflux was inhibited by increasing external potassium, and net potassium efflux was inhibited by increasing external sodium. Thus, the movement of either cation is coupled to, and can be driven by, the gradient of its co-ion. There is no evidence of trans stimulation of co-transport by either cation. The system also has a specific anion requirement satisfied only by chloride or bromide. Shifting the membrane potential by varying either external chloride (at constant internal chloride) or external potassium (at constant internal potassium in the presence of valinomycin and DIDs [4,4'-diisothiocyano-2,2'-disulfonic acid stilbene]), has no effect on nor-epinephrine-stimulated net sodium transport. Thus, this co-transport system is unaffected by membrane potential and is therefore electrically neutral. Finally, under the latter conditions-when Em was held constant near EK and chloride was not at equilibrium-net sodium extrusion against a substantial electrochemical gradient could be produced by lowering external chloride at high internal concentrations, thereby demonstrating that the anion gradient can also drive co-transport. We conclude, therefore, that chloride participates directly in the co-transport of [Na + K + 2Cl].

scholarly journals Sodium Efflux and Potential Differences across the Irrigated Gill of Sea Water-Adapted Rainbow Trout (Salmo gairdneri)

1974 ◽  
Vol 64 (2) ◽  
pp. 135-147 ◽  
Author(s):  
Lewis Greenwald ◽  
Leonard B. Kirschner ◽  
Martin Sanders
Keyword(s):  
Rainbow Trout ◽  
Sea Water ◽  
Irrigation System ◽  
Body Fluids ◽  
Salmo Gairdneri ◽  
Adequate Model ◽  
Sodium Efflux ◽  
Order Of Magnitude ◽  
Sodium Extrusion ◽  
Trout Gill

Sodium extrusion (JoutNa) was measured across the gills of rainbow trout, Salmo gairdneri, adapted to sea water (SW) using a gill-irrigation system of small volume. The potential difference (TEP) was also measured under similar conditions. JoutNa was usually between 100–250 µeq (100 g)–1 h–1, about an order of magnitude faster than in fresh water (FW)-adapted trout, but slower than has been reported for any other marine teleost. The TEP was between 10–11 mV, body fluids positive to SW. When the external medium was changed from SW to FW JoutNa was reduced to about 25 % of the initial value, and the TEP was reduced by 40–50 mV (i.e. body fluids negative by 30–40 mV). Addition of either Na+ or K+ in SW concentrations reversed the changes; JoutNa increased and the gill repolarized. The electrical behavior and sodium efflux in irrigated trout gill is qualitatively the same as has been reported for unanaesthetized, free-swimming fish of other species. Thus, the irrigated gill provides an adequate model for studying the mechanism of sodium extrusion in marine teleosts.

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.

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