Hyponatremia-induced brain edema in guinea pigs is reduced by treatment with the novel anion transport inhibitor L-644, 711

Deoxygenation-induced cation movements in sickle cells were inhibited 80% to 85% by the anion transport inhibitor, 4,4′-diisothiocyano- 2,2′disulfostilbene (DIDS). Morphologic sickling was not altered by DIDS treatment, demonstrating that morphologic sickling was not sufficient to produce cation leaks in sickle cells. DIDS inhibition of deoxygenation-induced cation flux was not affected when l- replaced Cl- , indicating that conductive anion movements did not limit cation flux in deoxygenated cells treated with DIDS. Inhibition was irreversible after preincubation with DIDS at 37 degrees C for 20 minutes, and was not affected by the oxygenation state of cells at the time of drug exposure. Sulfate self-exchange was inhibited at lower DIDS concentrations than was deoxygenation-induced flux. Incubation of cells with DIDS at 4 degrees C produced progressive blockade of sulfate exchange, but did not alter deoxygenation-induced cation fluxes. Other stilbene disulfonates, including compounds incapable of covalent reactions, also inhibited deoxygenation-induced cation movements, although several other inhibitors of anion exchange did not. Dissociation of the inhibition of anion exchange and deoxygenation- induced cation flux indicates that the DIDS effect on deoxygenation- induced cation movements does not involve the well-characterized stilbene binding site of the anion exchanger. These data provide evidence for a membrane constituent on the external surface of oxygenated sickle cells capable of interacting with DIDS to prevent the increase in cation permeability associated with sickling.

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Temperature dependence of anion transport inhibitor binding to human red cell membranes

Biophysical Chemistry ◽

10.1016/0301-4622(85)80072-7 ◽

1985 ◽

Vol 23 (1-2) ◽

pp. 139-145 ◽

Cited By ~ 7

Author(s):

Richard G. Posner ◽

James A. Dix

Keyword(s):

Temperature Dependence ◽

Cell Membranes ◽

Anion Transport ◽

Red Cell ◽

Inhibitor Binding ◽

Transport Inhibitor ◽

Red Cell Membranes

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Further characterization of the sorbitol permease in PAP-HT25 cells

AJP Cell Physiology ◽

10.1152/ajpcell.1994.267.2.c514 ◽

1994 ◽

Vol 267 (2) ◽

pp. C514-C519 ◽

Cited By ~ 17

Author(s):

S. Napathorn ◽

K. R. Spring

Keyword(s):

Specific Inhibitor ◽

Anion Transport ◽

Disulfonic Acid ◽

Bathing Solution ◽

Sugar Alcohols ◽

Transport Inhibitor ◽

No Inhibition

The sorbitol permease enables the efflux of sorbitol from cultured rabbit papillary cells (PAP-HT25) in response to a reduction in osmolality. The anion transport inhibitor 5-nitro-2-(3-phenylpropylamino)benzoate (100 microM) inhibited efflux by 92%, and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (0.5 mM) reduced efflux by 40%. 2,4-Dinitrobenzenesulfonate and p-chloromercuriphenylsulfonic acid had no effect. The protease trypsin (0.05 mg/ml) reduced sorbitol efflux by 53%, pronase (0.01 mg/ml) by 47%, and papain (0.1 mg/ml) by 49%; chymotrypsin had no effect. Sugars and sugar alcohols at different concentrations (10-200 mM) in the bathing solution did not influence sorbitol efflux. Determination of the osmotically induced influx of sugar alcohols showed that xylitol uptake was faster than that of sorbitol; 6-deoxysorbitol was slower; L-sorbitol, arabitol, galactitol, and 2-deoxysorbitol entered at the same rate as sorbitol; and maltitol did not enter the cells. Sorbitol and 6-deoxysorbitol at 9 mM competitively inhibited [14C]sorbitol influx by 24 and 32%, respectively, whereas xylitol, taurine, betaine, and myo-inositol showed no inhibition. We conclude that 1) a specific inhibitor of the permease was not found, 2) the sorbitol permease or associated regulator is a protein, and 3) the C-6 atom of sorbitol is important in the selectivity of the permease.

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