Specific drug sensitive transport pathways for chloride and potassium ions in steady-state ehrlich mouse ascites tumor cells

Aull, Felice

doi:10.1016/0005-2736(82)90287-5

Cited by 21 publications

(17 citation statements)

References 12 publications

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“…In 150 mM chloride medium, however, we concluded, based on experiments with bumetanide (Hoffmann et al, 1983), that the co-transport seemed to be negligible under steady-state conditions. Aull (1982) has demonstrated a DIDSinsensitive, furosemide-sensitive flux also in a high chloride medium. Since the DIDS-insensitive flux found in the present paper is significantly higher than the conductive flux, the relation of this flux to the different transport systems cannot be defined with certainty.…”

Section: Discussionmentioning

confidence: 98%

“…We have previously shown that in the steady state about 95% of the chloride transport in Ehrlich ascites cells is mediated by an electrically silent process (Hoffmann et al, 1979). This electrically silent anion transfer has been found to occur by two separate mechanisms (Hoffman et al, 1981;SjCholm et al, 1981;Aull, 1982;Hoffmann, 1982). One mechanism is an anion exchange system.…”

Section: Introductionmentioning

confidence: 99%

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Identification of the anion exchange protein of ehrlich cells: A kinetic analysis of the inhibitory effects of 4,4′-diisothiocyano-2,2′-stilbene-disulfonic acid (DIDS) and labeling of membrane proteins with3H-DIDS

1986

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In Ehrlich ascites tumor cells 4,4'-diisothiocyano-2,2'-stilbene-disulfonic acid (DIDS) inhibits the chloride exchange both reversibly and irreversibly. The reversible inhibition is practically instantaneous and of a competitive nature with Ki about 2 microM at zero chloride concentration. This is succeeded by a slow irreversible binding of DIDS to the transporter, with a chloride dependence suggesting binding to the same site as for reversible DIDS binding/inhibition. To identify the membrane protein involved in anion exchange, cells were labeled with 3H-DIDS. Incubation of cells for 10 min with 25 microM DIDS at pH 8.2 leads to more than 95% inhibition of the DIDS-sensitive chloride exchange flux when the chloride concentration is low (15 mM). This condition was used for the 3H-DIDS-labeling experiments. After incubation the cells were disrupted, the membranes isolated and solubilized, and the proteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The distribution of the 3H-activity in the gel showed only one major peak, which could be related to protein with a mol wt of about 30,000 Daltons. The number of transport sites was estimated at about 400,000 per cell, and from the DIDS-sensitive chloride flux under steady-state conditions we calculate a turnover number of 340 ions per sec per site.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Identification of the anion exchange protein of ehrlich cells: A kinetic analysis of the inhibitory effects of 4,4′-diisothiocyano-2,2′-stilbene-disulfonic acid (DIDS) and labeling of membrane proteins with3H-DIDS

1986

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“…(ii) The volume recovery was strongly inhibited by furosemide and bumetanide which have been reported to inhibit cotransport systems in Ehrlich cells (Geck et al, 1978;Aull, 1981Aull, , 1982.…”

Section: Discussionmentioning

confidence: 99%

Na+, Cl− cotransport in Ehrlich ascites tumor cells activated during volume regulation (regulatory volume increase)

1983

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Ehrlich ascites cells were preincubated in hypotonic medium with subsequent restoration of tonicity. After the initial osmotic shrinkage the cells recovered their volume within 5 min with an associated KCl uptake. The volume recovery was inhibited when NO-3 was substituted for Cl-, and when Na+ was replaced by K+, or by choline (at 5 mM external K+). The volume recovery was strongly inhibited by furosemide and bumetanide, but essentially unaffected by DIDS. The net uptake of Cl- was much larger than the value predicted from the conductive Cl- permeability. The undirectional 36Cl flux, which was insensitive to bumetanide under steady-state conditions, was substantially increased during regulatory volume increase, and showed a large bumetanide-sensitive component. During volume recovery the Cl- flux ratio (influx/efflux) for the bumetanide-sensitive component was estimated at 1.85, compatible with a coupled uptake of Na+ and Cl-, or with an uptake via a K+,Na+,2Cl- cotransport system. The latter possibility is unlikely, however, because a net uptake of KCl was found even at low external K+, and because no K+ uptake was found in ouabain-poisoned cells. In the presence of ouabain a bumetanide-sensitive uptake during volume recovery of Na+ and Cl- in nearly equimolar amounts was demonstrated. It is proposed that the primary process during the regulatory volume increase is an activation of an otherwise quiescent, bumetanide-sensitive Na+,Cl- cotransport system with subsequent replacement of Na+ by K+ via the Na+/K+ pump, stimulated by the Na+ influx through the Na+,Cl- cotransport system.

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“…The recovery occurs despite the fact that the bathing solution osmolality remains different from that of control Ringer's. The return of the cell to its original volume has been termed "volume regulation"; similar behavior has been described in red blood cells [8-10, 26, 30, 34], ascites tumor cells [4,5,19,27], isolated rabbit proximal tubules [20,21,33], lymphocytes [7,11,[22][23][24][25] and frog skin epithelium [41]. The volume regulatory increase which occurs during exposure of the apical surface of the cells to hypertonic perfusates has been previously studied by light microscopic [14,35] and electrophysiologic approaches [15,16].…”

Section: Introductionmentioning

confidence: 92%

“…ACTIVATION OF KC1 COTRANSPORT DURING VOLUME REGULATORY DECREASE Several investigators have suggested that KC1 cotransport normally occurs across the basolateral membrane of epithelial cells [2,18,[36][37][38], as well as across the membranes of other cells [4][5][6]32].…”

Section: Mechanism Of Kc1 Exit During Volume Regulatory Decreasementioning

confidence: 99%

Volume regulation byNecturus gallbladder: Basolateral KCl exit

1984

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Swelling of the epithelial cells of Necturus gallbladder caused by an 18% reduction in the osmolality of the mucosal bath is followed by rapid volume readjustment. This volume regulatory decrease requires Cl and is sensitive to the K and Cl gradients across the basolateral cell membrane. Volume regulatory decrease is not inhibited by amiloride, SITS, ouabain or bicarbonate removal. The process is blocked by bumetanide in the serosal bath. Measurement of the intracellular activities of K and Cl and the rate of volume regulation under five different experimental conditions showed that KCl exited from the cell across the basolateral membrane with a stoichiometry of 3 K to 2 Cl. This KCl exit process appears to be transiently activated following the reduction in osmolality of the mucosal perfusate.

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Specific drug sensitive transport pathways for chloride and potassium ions in steady-state ehrlich mouse ascites tumor cells

Cited by 21 publications

References 12 publications

Identification of the anion exchange protein of ehrlich cells: A kinetic analysis of the inhibitory effects of 4,4′-diisothiocyano-2,2′-stilbene-disulfonic acid (DIDS) and labeling of membrane proteins with3H-DIDS

Identification of the anion exchange protein of ehrlich cells: A kinetic analysis of the inhibitory effects of 4,4′-diisothiocyano-2,2′-stilbene-disulfonic acid (DIDS) and labeling of membrane proteins with3H-DIDS

Na+, Cl− cotransport in Ehrlich ascites tumor cells activated during volume regulation (regulatory volume increase)

Volume regulation byNecturus gallbladder: Basolateral KCl exit

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