Membrane transport of sodium ions in erythrocytes of the american black bear, Ursus americanus

doi:10.1016/0300-9629(90)90046-U

Comparative Biochemistry and Physiology Part A: Physiology

Volume 96, Issue 1, 1990, Pages 91-96

Comparative Biochemi...

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Abstract

1.
1. Membrane transport of Na ions was investigated in red blood cells of bears by methods of measurement of unidirectional isotopic fluxes.
2.
2. Like red blood cells of dogs, bear red cells contain a high Na concentration and low concentrations of K and ATP.
3.
3. As in dog red cells, Na efflux from bear cells was not inhibited by ouabain but was activated by the presence of Ca in the medium, possibly indicating the presence of a Na-Ca exchange mechanism.
4.
4. ATP depletion of cells was accelerated by Ca in the medium, consistent with the presence of a strong ATP-dependent Ca pump.
5.
5. As in other carnivore red cells, Na influx into bear cells was strongly activated by shrinkage and inhibited by swelling. Shrinkage-activated influx was blocked by amiloride.
6.
6. Amiloride-sensitive influx was activated by cytoplasmic Ca and also correlated with the presence of a Na-dependent, amiloride-sensitive H loss.
7.
7. Amiloride-sensitive Na influx exhibited a strong seasonal cycle with a minimum in the middle of the hibernation period, suggesting a possible avenue of cellular energy conservation.

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Reduced ion transport in erythrocytes of male Sprague-Dawley rats during starvation
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The temperature dependence of passive potassium permeability in mammalian erythrocytes
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Interactions of sodium transport and cellular volume in the cat erythrocyte

There are more references available in the full text version of this article.

Cited by (17)

Increased oxidative stress and decreased activities of Ca2+/Mg2+-ATPase and Na+/K+-ATPase in the red blood cells of the hibernating black bear
2002, Life Sciences
During hibernation, animals undergo metabolic changes that result in reduced utilization of glucose and oxygen. Fat is known to be the preferential source of energy for hibernating animals. Malonyldialdehyde (MDA) is an end product of fatty acid oxidation, and is generally used as an index of lipid peroxidation. We report here that peroxidation of lipids is increased in the plasma and in the membranes of red blood cells in black bears during hibernation. The plasma MDA content was about four fold higher during hibernation as compared to that during the active, non-hibernating state (P < 0.0001). Similarly, MDA content of erythrocyte membranes was significantly increased during hibernation (P < 0.025). The activity of Ca²⁺/Mg²⁺-ATPase in the erythrocyte membrane was significantly decreased in the hibernating state as compared to the active state. Na⁺/K⁺-ATPase activity was also decreased, though not significant, during hibernation. These results suggest that during hibernation, the bears are under increased oxidative stress, and have reduced activities of membrane-bound enzymes such as Ca²⁺/Mg²⁺-ATPase and Na⁺/K⁺-ATPase. These changes can be considered part of the adaptive for survival process of metabolic depression.
Symposium on diversity of membrane cation transport in vertebrate red blood cells. An overview
1992, Comparative Biochemistry and Physiology -- Part A: Physiology
Diversities of transport of sodium in rodent red cells
1992, Comparative Biochemistry and Physiology -- Part A: Physiology
- 1.
  1. Na-K pumps of rodent red cells reveal variations among species in terms of kinetic properties such as ouabain sensitivity, Na/K coupling and temperature sensitivity and variations within an individual organism related to such physiological challenges as K deficiency, calorie deficiency and seasonal changes in temperature.
- 2.
  2. Passive Na entry among rodents collectively occurs through the same routes as in red cells of other mammals, but red cells of hamsters, rats and thirteen-lined ground squirrels lack or are deficient in an amiloride-sensitive, shrinkage-activated Na-H exchange.
- 3.
  3. In guinea-pig this pathway appears to be both activated and uncoupled by cooling from 37 to 20°C.
- 4.
  4. Red cells of rodents in general and hamsters in particular are rich in a Na-Mg exchange pathway. In hamsters, this appears to be the only amiloride-sensitive pathway in simple media.
- 5.
  5. In hamster cells, Na entry through the amiloride-sensitive Mg-activated pathway exhibits the same kinetics as previously shown for Na activation of Mg extrusion.
Volume-activated cation transport in dog red cells: Detection and transduction of the volume stimulus
1992, Comparative Biochemistry and Physiology -- Part A: Physiology
- 1.
  1. Carnivore red cells lose their Na/K pump capability as they develop from erythroblasts to reticulocytes to mature cells. They defend their fluid volume by utilizing the Ca/Na exchanger as a Na extrusion pump, the energy for which is ultimately derived from active Ca transport.
- 2.
  2. Swelling-induced [K-Cl] cotransport and shrinkage-induced Na/H exchange are regulated in a coordinated fashion in dog red cells. Circumstantial evidence points to a regulatory protein kinase-phosphatase system.
- 3.
  3. Dog red cells detect changes in their fluid volume, not by virtue of membrane distortion, but by alterations in the concentrations of cytoplasmic macromolecules induced by swelling or shrinkage.
Ferret red cells: Na/Ca exchange and NaKCl cotransport
1992, Comparative Biochemistry and Physiology -- Part A: Physiology
The primary pathway for K influx in ferret red cells is the NaKCl cotransporter and the primary pathway for Ca influx is the Na/Ca exchanger. This makes ferret red cells favorable models for the study of these two transport systems. The evidence that Na/Ca exchange is of primary importance for steady state cell volume regulation and the Na-K-Cl cotransport has a minor role is presented. The approaches to, and results of, the determination of the stoichiometry, of the mechanism, and of the regulation by ATP and Mg, for Na/Ca exchange is contrasted with that taken for NaKCl cotransport.
Activation of ion transport pathways by changes in cell volume
1991, BBA - Reviews on Biomembranes

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Comparative Biochemistry and Physiology Part A: Physiology

Abstract

References (14)

Ca-activated Na fluxes in human red cells, amiloride sensitivity

J. biol. Chem.

Reduced ion transport in erythrocytes of male Sprague-Dawley rats during starvation

J. Nutr.

Amiloride: a molecular probe of sodium transport in tissues and cells

Am. J. Physiol.

Amiloride sensitive Na transport in human red cells: evidence for a Na-H exchange system

J. Membr. Biol.

The temperature dependence of passive potassium permeability in mammalian erythrocytes

J. Physiol., Lond.

Ouabain binding and potassium transport in young and old populations of human red cells

Membr. Biochem.

Interactions of sodium transport and cellular volume in the cat erythrocyte

Cited by (17)

Increased oxidative stress and decreased activities of Ca<sup>2+</sup>/Mg<sup>2+</sup>-ATPase and Na<sup>+</sup>/K<sup>+</sup>-ATPase in the red blood cells of the hibernating black bear

Symposium on diversity of membrane cation transport in vertebrate red blood cells. An overview

Diversities of transport of sodium in rodent red cells

Volume-activated cation transport in dog red cells: Detection and transduction of the volume stimulus

Ferret red cells: Na/Ca exchange and NaKCl cotransport

Activation of ion transport pathways by changes in cell volume