Sodium and potassium permeability of red blood cells in dependence of the pH

Pfleger, K.; Rummel, W.; Seifen, Ernst

doi:10.1007/bf01844105

Cited by 13 publications

(4 citation statements)

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“…The observed pH dependence of Na movements catalysed by exchange diffusion in the beef red cell is 418 R. MOTAIS OUABAIN-INSENSITIVE Na EXCHANGE DIFFUSION 419 very different from the pH dependent of Na movements in other erythrocytes, either high K (rabbit) or high Na cells (cat). Indeed, in rabbit erythrocytes suspended in their own plasma, Pfleger, Rummel & Seifen (1967) observed a marked pH dependence of the Na net movements between pH 6 and 8-5 with a minimum around pH 7 and a maximum at pH 6-6. They demonstrated that the measured net fluxes largely represented passive fluxes and that active fluxes were little influenced by the hydrogen ion concentration.…”

Section: Discussionmentioning

confidence: 99%

Sodium movements in high‐sodium beef red cells: properties of a ouabain‐insensitive exchange diffusion

Motais¹

1973

The Journal of Physiology

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SUMMARY1. The relative importance of the Na efflux components in beef red cells has been evaluated. The component which is insensitive to ouabain, which does not require external K but depends on the presence of external Na, accounts for about 90 % of the total Na efflux.2. The experiments reported in this paper are consistent with the presence of an ouabain-insensitive Na+-Na+ exchange process accounting for this ouabain-insensitive external Na dependent efflux.3. A strictly parallel behaviour of influx and efflux is observed when the pH is altered. The exchange diffusion process is inhibited over 90 % by a decrease in pH from range pH 8-0-5 5. 4. Both Na efflux and influx are markedly increased by raising the temperature from 27 to 370 C. 5. Energy depleted cells and fresh cells behave similarly in respect to Na movements. In depleted resealed ghosts, a large Na-dependent efflux occurs. No chemical energy and no special nucleotide is required for the Na+-Na+ exchanges.6. When the external or internal Na concentrations are changed, a parallel behaviour of influx and efflux is observed.7. The relation between the magnitude of the exchange diffusion flux and the external or internal Na concentration fits quite well the Michaelis-Menten equation suggesting that only one Na+ reacts with the transport mechanism. The affinity for Na is lower however at the outer surface than at the inner border of the membrane.8. The relation between this exchange process, the ouabain-insensitive Na-Na exchanges found in human red cell, and Ussing's model of exchange diffusion is discussed.

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Section: Discussionmentioning

confidence: 99%

Sodium movements in high‐sodium beef red cells: properties of a ouabain‐insensitive exchange diffusion

Motais¹

1973

The Journal of Physiology

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“…They studied the rate of re-swelling of red cells in buffered salt solutions made hypertonic by the addition of erythritol, and their data indicated that glucose retarded erythritol permeation. According to personal communications made to Pfleger, Rummel & Seifen (1967) inhibition of erythritol influx by phlorrhizin has been observed by W. Wilbrandt, and H. Passow has noted that 60 % of erythritol enters the red 448 ER YTHRITOL PERMEABILITY OF RED CELLS cell by means of the glucose transfer system. The present work provides detailed quantitative data about the competition, and shows that there is in fact an alternative erythritol pathway, unavailable to hexoses.…”

Section: Erythritol Permeability Of Red Cellsmentioning

confidence: 99%

Effects of hexoses and anions on the erythritol permeability of human red cells

Wieth¹

1971

The Journal of Physiology

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SUMMARY1. The effect of hexoses and of the anions chloride, thiocyanate, and salicylate on the permeability of human red cells to [14C]erythritol has been studied.2. It was confirmed that erythritol competes with glucose, mannose, and galactose for the hexose transfer system of the red cell membrane.Approximately 25 % of the erythritol influx was insensitive to the presence of hexoses or phloretin. Identical maximum degrees of inhibition were obtained with 0 3 M glucose and with phloretin (0.5 x 10-3M). In the absence of competing inhibitors the erythritol permeability, P, was 1-2 x 10-7 cm/sec at 380 C. At maximum inhibition P was 0 3 x 10-7cm/sec.3. Erythritol is able to penetrate the membrane by two pathways, only one of which is sensitive to hexoses. Both hexose-sensitive and hexoseinsensitive erythritol influx are well described by first-order diffusion kinetics. The affinity of erythritol for the hexose transfer system is very low, and the half saturation constants of hexoses can be determined from their ability to retard erythritol permeation. The following values were found for the half saturation of the transport system with hexoses at 380 C: glucose 6 mm, mannose 11 mm, and galactose 40 mM.4. Thiocyanate and salicylate reduce the hexose-sensitive fraction of erythritol influx, but the hexose-insensitive erythritol permeability is not affected when chloride is replaced by the foreign anions. This applies to the whole temperature range between 0 and 380 C, where the ionic permeabilities of red cells have been shown to be profoundly changed by thiocyanate and salicylate.

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“…In addition to human erythrocytes, red cells of beef, sheep and rabbits are studied because of their characteristic differences in Na +-K + pump and ouabain-resistant Na+-Na + exchange activities. Rabbit erythrocytes were selected as an example of red cells with a higher Na+-K § pump activity and a faster ouabain-resistant Na+-Na + exchange than are found in human erythrocytes (Pfleger, Rummel & Seifen, 1967;Rettori et al, 1969;Villamil & Kleeman, 1969). Furthermore, sheep (and beef) exhibit a genetic dimorphism with respect to their red cell Na § and K § content and Na+-K + pump activity, respectively (Tosteson & Hoffman, 1960;Motais, 1973).…”

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confidence: 99%

Studies on lithium transport across the red cell membrane

Duhm

Becker

1979

J. Membrain Biol.

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Ouabain-resistant Na+-Li+ countertransport was studied on erythrocytes of man, sheep, rabbit, and beef. A transport system, exchanging Li+ for Na+ in a ratio of 1:1, was present in all four species. Li+ uptake by the exchange system increased 30-fold in the order man less than HK-sheep less than LK-sheep less than rabbit less than LK-beef. This order is identical to that of ouabain-resistant Na+-Na+ exchange in these species, but bears no relation to the Na+-K+ pump activity. The activity of the Na+-Li+ exchange system varied up to 7 and 16-fold among individual red cell specimens from man and beef, the variability being much smaller in sheep and rabbit erythrocytes. The affinities of the system for Li+ and Na+ were similar among the species and individuals (half saturation of the external site at about 1 mM Li+ and 50 mM Na+, respectively). 50-60% of Na+-Li+ exchange was blocked by N-ethylmaleimide in all species. p-Chloromercuribenzene sulfonate inhibited the exchange only in beef and sheep erythrocytes (60-80%). The two SH-reagents act by decreasing the maximum activity of the system, whilst leaving its affinity for Li+ unaltered. Phloretin was a potent inhibitor in all species. 1 mM each of furosemide, ethacrynic acid, and quinidine induced only a slight inhibition. The Na+-Li+ exchange of human and beef erythrocytes increased 3.5-fold upon elevation of the extracellular pH from 6 to 8.5, the pH-dependence arising from a change in affinity of the system for the cations and being similar to that reported for ouabain-resistant Na+-Na+ exchange in beef erythrocytes. It is concluded that a transport system exists in the red cell membranes of the four species which can mediate ouabain-resistant exchange of either Na+ for Na+, Na+ for Li+, or Li+ for Li+. The exchange system exhibits essentially identical transport characteristics in the four species, but shows a marked inter- and intra-species variability in maximum transport capacity and some differences in susceptibility towards inhibitors. A similar transport system is probably present also in other tissues. The exchange system seems to be distinct from the conventional Na+-K+ pump and shows no clear relation to one of the furosemide-sensitive, ouabain-resistant Na+ transport systems described in the literature.

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Sodium and potassium permeability of red blood cells in dependence of the pH

Cited by 13 publications

References 12 publications

Sodium movements in high‐sodium beef red cells: properties of a ouabain‐insensitive exchange diffusion

Sodium movements in high‐sodium beef red cells: properties of a ouabain‐insensitive exchange diffusion

Effects of hexoses and anions on the erythritol permeability of human red cells

Studies on lithium transport across the red cell membrane

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