Glycine transport by hemolysed and restored pigeon red cells effects of a domnan-induced electrical potential on entry and exit kinetics

Vidaver, George A.; Shepherd, Sara L.; Lagow, Joyce B.; Wiechelman, Karen J.

doi:10.1016/0005-2736(76)90468-5

Cited by 9 publications

(3 citation statements)

References 37 publications

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“…Vidaver (1964b) did not state the pH of the incubation media he used for his original experiments with pigeon erythrocyte ghosts, but the composition of his buffer indicates that the pH probably was about 6.8, which we found to be satisfactory. However, more recently a detailed analysis of the glycine system was made with the use of results derived partly from the effects of pH on glycine uptake by pigeon erythrocyte ghosts (Vidaver et al, 1976). The findings reported here suggest that the conclusions drawn from that study should be reviewed, although the properties of the ghosts used then might well have differed from those described here because the preparative methods were different.…”

Section: Properties Ofresealed Ghostsmentioning

confidence: 99%

“…Na+-dependent uptake of amino acids and sugars by various cells and tissues has given rise to the 'sodium-gradient' theory of membrane transport (reviewed by Eddy, 1975;Crane, 1977). Some of the most convincing evidence supporting this concept derives from the work of Vidaver and his colleagues on the transport of glycine by both intact pigeon erythrocytes and resealed ghosts from these cells (Vidaver, 1964a(Vidaver, ,b,c,d, 1971Vidaver et al, 1964Vidaver et al, , 1976Vidaver & Shepherd, 1968;Imler & Vidaver, 1972; & Vidaver, , 1973). This transport system, however, is almost certainly peculiar to glycine, and several other amino acids are transported in the pigeon erythrocyte via Na+-dependent processes that have different characteristics from the glycine system (Wheeler & Christensen, 1967;Eavenson & Christensen, 1967;Christensen, 1975).…”

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confidence: 99%

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Amino acid transport by resealed ghosts from pigeon erythrocytes

Wheeler¹

1982

Biochemical Journal

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Resealed ghosts from pigeon erythrocytes were shown to haemolyse during incubation in isotonic media with pH values greater than about 7 and high concentrations of Na+ inside the ghosts seemed to enhance this effect. At lower pH values the ghosts were stable but still highly permeable to Na+ and K+, and moderately permeable to sucrose. Under the latter conditions the ghosts transported amino acids in a way qualitatively but not quantitatively similar to intact erythrocytes. The Na+-dependent transport of serine and alanine by the ghosts consisted essentially of an exchange of extracellular for intracellular amino acids, with no significant net flux. In contrast, net fluxes of glycine in the direction of the Na+-concentration gradient across the ghost membrane were demonstrated. However, under one condition a small net influx of glycine occurred against the prevailing Na+-concentration gradient. Unlike Na+-dependent glycine uptake, the uptake of six other amino acids by intact pigeon erythrocytes was not influenced by the nature of the anion present. The significance of these findings in relation to previous work on the Na+-gradient hypothesis of membrane transport is discussed.

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Section: Properties Ofresealed Ghostsmentioning

confidence: 99%

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confidence: 99%

Amino acid transport by resealed ghosts from pigeon erythrocytes

Wheeler¹

1982

Biochemical Journal

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“…Therefore, it is generally assumed that the maximal velocity of solute uptake should be sensitive to changes in membrane potential. Model calculations are based on this assumption and revealed a complex interference of electric potential with V max and Km values [8] and experiments with pigeon red cells seem to prove it [9]. In contrast the maximal rate of hexose uptake at pH 6.0 in Chlorella exhibited no dependance on electric membrane potential over a considerable range.…”

Section: Elsevierlnorth-holland Biomedical Pressmentioning

confidence: 99%

A possible mechanistic role of the membrane potential in proton—sugar cotransport of Chlorella

1978

FEBS Letters

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Volume-sensitive taurine transport in fish erythrocytes

1987

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Taurine plays an important role in cell volume regulation in both vertebrates and invertebrates. Erythrocytes from two euryhaline fish species, the eel (Anguilla japonica) and the starry flounder (Platichthys stellatus) were found to contain high intracellular concentrations of this amino acid (approximately equal to 30 mmol per liter of cell water). Kinetic studies established that the cells possessed a saturable high-affinity Na+-dependent beta-amino-acid transport system which also required Cl- for activity (apparent Km (taurine) 75 and 80 microM; Vmax 0.85 and 0.29 mumol/g Hb per hr for eel (20 degrees C) and flounder cells (10 degrees C), respectively. This beta-system operated with an apparent Na+/Cl-/taurine coupling ratio of 2:1:1. A reduction in extracellular osmolarity, leading to an increase in cell volume, reversibly decreased the activity of the transporter. In contrast, low medium osmolarity stimulated the activity of a Na+-independent nonsaturable transport route selective for taurine, gamma-amino-n-butyric acid and small neutral amino acids, producing a net efflux of taurine from the cells. Neither component of taurine transport was detected in human erythrocytes. It is suggested that these functionally distinct transport routes participate in the osmotic regulation of intracellular taurine levels and hence contribute to the homeostatic regulation of cell volume. Volume-induced increases in Na+-independent taurine transport activity were suppressed by noradrenaline and 8-bromoadenosine-3', 5'-cyclic monophosphate, but unaffected by the anticalmodulin drug, pimozide.

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Glycine transport by hemolysed and restored pigeon red cells effects of a domnan-induced electrical potential on entry and exit kinetics

Cited by 9 publications

References 37 publications

Amino acid transport by resealed ghosts from pigeon erythrocytes

Amino acid transport by resealed ghosts from pigeon erythrocytes

A possible mechanistic role of the membrane potential in proton—sugar cotransport of Chlorella

Volume-sensitive taurine transport in fish erythrocytes

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