Effect of bicarbonate, pH, methazolamide and stibenes on the intracellular potentials of cultured bovine corneal endothelial cells

Jentsch, Thomas J.; Koch, Marianne; Bleckmann, Horst; Wiederholt, Michael

doi:10.1007/bf01869198

Cited by 50 publications

(33 citation statements)

References 33 publications

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“…Previous studies, however, noted lit tle or no effect of amiloride under resting con ditions [ 19], Similarly, experiments using ace tate (data not included) to induce cellular acidification also caused an overshoot alkalinization of pHj when the ambient solution was returned to normal Ringer. These data confirm those obtained in other studies using similar techniques [ 19] There appears to be little effect of membrane potential, at least depolarization, on pHj although a depen dence of intracellular electrical potential dif ference on pHj has been strongly suggested previously [32]. In these experiments, acidifi cation of the cellular interior usually leads to a hyperpolarization, and alkalinization was as sociated with depolarization.…”

Section: Discussionsupporting

confidence: 81%

“…In these experiments, acidifi cation of the cellular interior usually leads to a hyperpolarization, and alkalinization was as sociated with depolarization. These changes were usually transient in nature and lasted, under the given experimental conditions, less than 10 min [32], These data are not incom patible since pHj could drive membrane po tential through alterations of membrane charges, whereas alterations in membrane po tential induced by a different mechanism would not necessarily induce a change in pHj.…”

Section: Discussionmentioning

confidence: 95%

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Intracellular pH of Tissue-Cultured Bovine Corneal Endothelial Cells

Chu

Keith²,

Yee³

et al. 1992

Ophthalmic Res

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Intracellular pH (pH_i) of bovine tissue-cultured corneal endothelial cells has been measured under several experimental conditions. Determinations were made on individual cells using video-imaging techniques that allowed assessment of 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein fluorescence at 440 and 490 nm. Each experiment had a calibration performed on a cell monolayer: this was performed using a high K⁺-nigericin solution. Resting pH_i was 7.25 ± 0.03 (n = 18) in bicarbonate solution at pH 7.4. Amiloride (1 mM) caused an acidification of approximately 0.2 U within 2 min: replacement with normal Ringer allowed a return to normal pH_i after an alkali overshoot. Exposure to 20 mM NH₄C1 caused alkalinization that became acidic upon washout of NH₄CI. In Na⁺-rich solution pH_i returned to normal after acidification but pH_i remained low in Na⁺-free solution until substituted by Na⁺-rich solution. Removal of HCO^-₃ from the bathing solution caused a nonsignificant acidification of pH_i by 0.1 U at 2 and 4 min, and 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS; 1 mM) acidified pH_i by 0.14 U at 2 min and 0.24 U at 4 min. Addition of DIDS (1 mM) in a HCO^-₃-free solution had no effect on pH_i. Hydrogen peroxide acidified pH_i by 0.3 U at 50 μM and 1 mM. These results indicate that a Na⁺:H⁺ antiport exists that regulates pH_i even at normal ambient pH in the presence of bicarbonate: this process becomes highly activated after an acid load. There is a DIDS-sensitive HCO^-₃ movement that is probably coupled to Na⁺ or Cl^-.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 95%

Intracellular pH of Tissue-Cultured Bovine Corneal Endothelial Cells

Chu

Keith²,

Yee³

et al. 1992

Ophthalmic Res

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“…It is unlikely that an apical K ϩ conductance is a contributing factor in this study, (15). In addition, inhibition of carbonic anhydrase can reduce the change in voltage response to HCO 3 Ϫ in corneal endothelium (19). To test if carbonic anhydrase activity was related to the HCO 3 Ϫ -dependent NH 4 ϩ inhibition of Cl Ϫ secretion, we used methazolamide to inhibit apical carbonic anhydrase.…”

Section: Discussionmentioning

confidence: 97%

Apical ammonium inhibition of cAMP-stimulated secretion in T84 cells is bicarbonate dependent

Worrell

Best

Crawford

et al. 2005

American Journal of Physiology-Gastrointestinal and Liver Physi

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Normal human colonic luminal (NH 4 ϩ ) concentration ( [NH 4 ϩ ]) ranges from ϳ10 to 100 mM. However, the nature of the effects of NH 4 ϩ on transport, as well as NH 4 ϩ transport itself, in colonic epithelium is poorly understood. We elucidate here the effects of apical NH 4 ϩ on cAMP-stimulated Cl Ϫ secretion in colonic T84 cells. In HEPESbuffered solutions, 10 mM apical NH 4 ϩ had no significant effect on cAMP-stimulated current. In contrast, 10 mM apical NH 4 ϩ reduced current within 5 min to 61 Ϯ 4% in the presence of 25 mM HCO 3 Ϫ . Current inhibition was not simply due to an increase in extracellular K ϩ -like cations, in that the current magnitude was 95 Ϯ 5% with 10 mM apical K ϩ and 46 Ϯ 3% with 10 mM apical NH 4 ϩ relative to that with 5 mM apical K ϩ . We previously demonstrated that inhibition of Cl Ϫ secretion by basolateral NH 4 ϩ occurs in HCO 3 Ϫ -free conditions and exhibits anomalous mole fraction behavior. In contrast, apical NH 4 ϩ inhibition of current in HCO 3 Ϫ buffer did not show anomalous mole fraction behavior and followed the absolute [NH 4 ϩ ] in K ϩ -NH 4 ϩ mixtures, where K ϩ concentration ϩ [NH 4 ϩ ] ϭ 10 mM. The apical NH 4 ϩ inhibitory effect was not prevented by 100 M methazolamide, suggesting no role for apical carbonic anhydrase. However, apical NH 4 ϩ inhibition of current was prevented by 10 min of pretreatment of the apical surface with 500 M DIDS, 100 M 4,4Ј-dinitrostilbene-2,2Ј-disulfonic acid (DNDS), or 25 M niflumic acid, suggesting a role for NH 4 ϩ action through an apical anion exchanger. mRNA and protein for the apical anion exchangers SLC26A3 [downregulated in adenoma (DRA)] and SLC26A6 [putative anion transporter (PAT1)] were detected in T84 cells by RT-PCR and Northern and Western blots. DRA and PAT1 appear to associate with CFTR in the apical membrane. We conclude that the HCO 3 Ϫ dependence of apical NH 4 ϩ inhibition of secretion is due to the action of NH 4 ϩ on an apical anion exchanger.

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“…Smaller doses of SITS were not effective since in two control experiments, the presence of 0-1 mM-SITS did not reduce the rate of intracellular acidification observed when Na+ was removed from the perfusate (data not shown). Also in other tissues high concentration (0 1-1 mM) of the stilbene derivatives SITS and 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS) have been reported to inhibit rheogenic Na+-HC3-co-transport (kidney: Baron & Boulpaep, 1983;Yoshitomi et al 1985;Biagi & Sohtell, 1986;Lopes et al 1987; cultured corneal endothelium: Jentsch et al 1984b;BSC1 cells: Jentsch et al 1986;oxyntic cells: Curci et al 1987;glial cells: Schlue & Deitmer, 1988).…”

Section: Effects Of Changes In the Hc03-concentrationmentioning

confidence: 99%

“…Rheogenic Na+-HCO3-co-transport has also been described in cultured bovine corneal endothelial cells (Jentsch, Keller, Koch & Wiederholt, 1984a;Jentsch, Koch, Bleckmann & Wiederholt, 1984b) and in a continuous cell line (BSC-1) derived from monkey kidney (Jentsch, Schill, Schwarz, Matthes, Keller & Wiederholt, 1985; Matthes, Keller & Wiederholt, 1986). Recently a rheogenic Na+-HCO3-cotransport system has been found in oxyntic cells of frog gastric mucosa (Curci, Debellis & Froemter, 1987), and in glial cells in the central nervous system of the leech (Schlue & Deitmer, 1988).…”

Section: Introductionmentioning

confidence: 99%

Rheogenic sodium‐bicarbonate co‐transport across the retinal membrane of the frog retinal pigment epithelium.

Cour

1989

The Journal of Physiology

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SUMMARY1. Na+ and HC03-transport across the retinal membrane of the frog retinal pigment epithelium was studied by means of double-barrelled Na+-and pH-selective microelectrodes. Transient changes in the intracellular pH and in the intracellular Na+ activity were monitored in response to abrupt changes in the Na+ concentration and in the HC03-concentration on the retinal side of the epithelium, and in response to transepithelial currents.2. Removal of Na+ from the retinal side of the epithelium caused a depolarization of the membrane potential across the retinal membrane, a decrease in the intracellular Na+ activity and a decrease in the intracellular pH.3. An increase in the HC03-concentration on the retinal side of the epithelium from 27-5 to 50 mm caused a hyperpolarization of the membrane potential across the retinal membrane, an increase in the intracellular Na+ activity and an increase in the intracellular pH.4. Passage of a transepithelial current of 30 ,uA in the choroid-to-retina direction caused an increase in the intracellular Na+ activity and an increase in the intracellular pH.

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Effect of bicarbonate, pH, methazolamide and stibenes on the intracellular potentials of cultured bovine corneal endothelial cells

Cited by 50 publications

References 33 publications

Intracellular pH of Tissue-Cultured Bovine Corneal Endothelial Cells

Intracellular pH of Tissue-Cultured Bovine Corneal Endothelial Cells

Apical ammonium inhibition of cAMP-stimulated secretion in T84 cells is bicarbonate dependent

Rheogenic sodium‐bicarbonate co‐transport across the retinal membrane of the frog retinal pigment epithelium.

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