Voltage dependence of DIDS-insensitive chloride conductance in human red blood cells treated with valinomycin or gramicidin.

Freedman, Jeffrey C.; Novak, Terri S.; Bisognano, John D.; Pratap, Promod R.

doi:10.1085/jgp.104.5.961

Cited by 21 publications

(37 citation statements)

References 48 publications

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“…In flux [19] and differential laser light scattering experiments [18], a DIDS-insensitive Cl -conductance in human RBCs has been characterized to activate at voltages more negative than -40 mV. DIDS-insensitive Clchannels have been identified at the single-channel level in trout RBCs [15].…”

Section: Discussionmentioning

confidence: 99%

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Chloride conductance and volume-regulatory nonselective cation conductance in human red blood cell ghosts

Huber

Gamper

Läng

2001

Pfl�gers Archiv European Journal of Physiology

156

129

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To identify the ion channels involved in erythrocyte volume regulation, whole-cell currents from human red blood cells (RBCs) were recorded in isotonic, hypotonic and hypertonic media. In isotonic NaCl bath solution, whole-cell currents rectified outwardly with reversal potentials (Vrev) between the equilibrium potential of Cl- (ECl) and that of nonselective cations (NSC), ENSC. Replacement of bath Cl by gluconate decreased outward conductance (G outward) by 43 +/- 6% (n = 5) and shifted Vrev with ECl indicating a high fractional Cl- conductance. Hypotonic cell swelling reversibly decreased G outward by 23 +/- 3% (n = 8) while hypertonic cell shrinkage reversibly increased G outward by 27 +/- 8% (n = 5). These shrinkage-activated and swelling-inactivated current fractions rectified outwardly with Vrev at ENSC suggesting that both fractions are generated by the same type of NSC channel. The shrinkage-activated deltaG outward decreased from 4.7 +/- 1.2 nS (n = 3) to 1.4 +/- 0.4 nS (n = 5) and 0.5 +/- 0.4 nS (n = 7) with the increase of pipette [Cl-] from 7 mM to 39 mM and 139 mM, respectively. Similarly, with this increase of pipette [Cl-], G outward under isotonic control conditions decreased from 8.2 +/- 1.4 nS (n = 5) to 7.4 +/- 1.0 nS (n = 20) and 4.1 +/- 0.7 nS (n = 17), due to the differing activity of these NSC channels. In conclusion, human RBCs express, besides a high fractional Cl- conductance, NSC channels that are regulated by cell volume and the cytosolic [Cl-].

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Section: Discussionmentioning

confidence: 99%

“…For instance, DIDS-insensitive and DIDS-sensitive Cl -conductances [17,18,19], which recycle Cl -for anion exchange, are either not or not directly defined electrophysiologically. This is mainly because of the technical difficulties inherent to patchclamping these cells.…”

Section: Introductionmentioning

confidence: 99%

Chloride conductance and volume-regulatory nonselective cation conductance in human red blood cell ghosts

Huber

Gamper

Läng

2001

Pfl�gers Archiv European Journal of Physiology

156

129

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“…The maximum variation in the values of a and b was 17 and 7 5%, respectively, in the five experiments of this series; the experiment illustrated in Figs 1B (Freeman, Bookchin, Ortiz & Lew, 1987), and additional reductions in cell osmolytes during prelytic swelling. These include HCl loss through the Jacobs-Stewart mechanism (Lew & Bookchin, 1986;Bisognano, Dix, Pratap, Novak & Freedman, 1993) (Lew & Bookehin, 1986;Freeman et al 1987;Freedman, Novak, Bisognano & Pratap, 1994; a compiled version of the red cell model programme used here, together with a concise guide, is available from the authors on request). The kcd values thus obtained were 0 8-1 0 h-', well within the range of earlier estimates of mean Cl permeabilities in human red cells (Hunter, 1977;Knauf et al 1977 …”

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confidence: 99%

Distribution of chloride permeabilities in normal human red cells.

Raftos

Bookchin

Lew

1996

The Journal of Physiology

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1. The rate of dehydration of K+ permeabilized red cells is influenced by their Clpermeability (PC1). In instances of pathological K+ permeabilization, cell-to-cell differences in PC1 may determine which red cells dehydrate most. The present study was designed to investigate whether PC1 differed significantly among red cells from a single blood sample.2. Previously available methods measure only the mean Pcl of red cell populations. We describe a 'profile migration' method in which dilute red cell suspensions in low-K+ media were permeabilized to K+ with a high concentration of valinomycin, rendering P01 the main rate-limiting factor for cell dehydration. As the cells dehydrated, samples were processed to obtain full haemolysis curves at precise times. Variations in PC1 among cells would have appeared as progressive changes in the profile of their haemolysis curves, as the curves migrated towards lower tonicities. 3. Red cells from five normal volunteers showed no change in profile of the migrating haemolysis curves, suggesting that their PC1 distributions were fairly uniform. Quantitative analysis demonstrated that intercell variation in PC1 was less than 7 5 %.4. Results obtained with this technique were analysed using the Lew-Bookchin red cell model. The calculated PC1 was within the normal range described in earlier studies.

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“…After 5 min, 1-3 μM valinomycin was added to the flask. 0.25 ml samples of suspension were aspirated at intervals into the sample port of the H*3 RTX blood analyzer to determine valinomycin-induced changes in mean cell volume (MCV) and in mean corpuscular hemoglobin concentration (CHCM), as described [16] with modification. Some cell suspensions were pretreated for 30 min with DIDS (10 μM), and used without further washing for experiments.…”

Section: Measurement Of Red Cell Anion Conductance By Valinomycin-actmentioning

confidence: 99%

“…The first approach monitored change in membrane potential measured as the change in extracellular pH (pH o ) in a suspension of CCCP-treated red cells in the presence and absence of valinomycin [4]. The second approach measured the rate of change of corpuscular hemoblobin concentration (mean) (CHCM) and mean corpuscular volume (MCV) in valinomycin-treated red cells [16]. The third approach measured 86 Rb efflux from valinomycin-treated red cells [2;3;9;17].…”

Section: Introductionmentioning

confidence: 99%

Reduced DIDS-sensitive chloride conductance in Ae1−/− mouse erythrocytes

Alper

Vandorpe

Peters

et al. 2008

Blood Cells, Molecules, and Diseases

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The resting membrane potential of the human erythrocyte is largely determined by a constitutive Cl -conductance ∼100-fold greater than the resting cation conductance. The 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS)-sensitive electroneutral Cl -transport mediated by the human erythroid Cl -/HCO 3 -exchanger, AE1 (SLC4A1, band 3) is ≥10,000-fold greater than can be accounted for by the Cl -conductance of the red cell. The molecular identities of conductive anion pathways across the red cell membrane remain poorly defined. We have examined red cell Cl -conductance in the Ae1 -/-mouse as a genetic test of the hypothesis that Ae1 mediates DIDSsensitive Cl -conductance in mouse red cells. We report here that wildtype mouse red cell membrane potential resembles that of human red cells in the predominance of its Cl -conductance. We show with four technical approaches that the DIDS-sensitive component of erythroid Cl -conductance is reduced or absent from Ae1 -/-red cells. These results are consistent with the hypothesis that the Ae1 anion exchanger polypeptide can operate infrequently in a conductive mode. However, the fragile red cell membrane of the Ae1 -/-mouse red cell exhibits reduced abundance or loss of multiple polypeptides. Thus, loss of one or more distinct, DIDS-sensitive anion channel polypeptide(s) from the Ae1 -/-red cell membrane cannot be ruled out as an explanation for the reduced DIDS-sensitive anion conductance.

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Voltage dependence of DIDS-insensitive chloride conductance in human red blood cells treated with valinomycin or gramicidin.

Cited by 21 publications

References 48 publications

Chloride conductance and volume-regulatory nonselective cation conductance in human red blood cell ghosts

Chloride conductance and volume-regulatory nonselective cation conductance in human red blood cell ghosts

Distribution of chloride permeabilities in normal human red cells.

Reduced DIDS-sensitive chloride conductance in Ae1−/− mouse erythrocytes

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