Regulation of intracellular pH (pHi) in proximal tubules of avian loopless reptilian-type nephrons

C. L. Martinez, O. H. Brokl, A. Shuprisha, D. E. Abbott, William H Dantzler

Research output: Contribution to journalArticle

Abstract

We examined pHi and its regulation in isolated nonperfused proximal tubules of chicken loopless nephrons (70-90% of nephrons in kidney) using pH-sensitive fluorescent dye BCECF. Under control conditions (HEPES buffer, pH 7.4; 37°C) resting pH was 7.18 ± 0.02 (mean ± SE). Addition of 20 mM NH4Cl to bath increased pH to 7.68 ± 0.03. Removal of NH4Cl from bath reduced pH to 6.95 ± 0.03. Rate of pHi change (dpHi/dt, pH U/s), intrinsic buffering capacity (βi, mM H+/pH U), basolateral NH3 flux (JNH3, nmol/cm2/s), and basolateral NH3 permeability (PNH3, cm/s × 10-3) were, respectively: 0.13 ± 0.01, 27.55 ± 3.42, 1.86 ± 0.16, and 3.80 ± 0.32. Control recovery rate (dpHi/dt) from acid pHi after NH4Cl removal was 4.98 ± 0.38 × 10-3 pH U/s. This dpHi/df was significantly (P < 0.05; paired studies) decreased by removal of Na+ (replacement with N-methyl-D-glucamine Cl-), simultaneous removal of Na+ and Cl- (replacement with N-methyl-D-glucamine-gluconate), or addition of DIDS, significantly increased by high K+ (75 mM) (depolarization of basolateral membrane); and unchanged by removal of Cl- (replacement with Na+-gjuconate) or addition of EIPA (1 mM) or Ba2+ (basolateral depolarization; blockage of K+ channels) Resting pH was significantly (P < 0.05; paired studies) decreased by Na+ removal or simultaneous Na+ and Cl- removal; significantly increased by high K+; and unchanged by Cl- removal alone or addition of Ba2+. Data do not fit concept of pHi regulation by usual basolateral transporters (Na+/H+ exchange; Na+-dependent and Na+-independent Cl- /HCO3- exchange; or Na+-HCO3--CO32- cotransporter). There may be Na--HCO3 cotransporter for basolateral HCO3- entry.

Original languageEnglish (US)
JournalFASEB Journal
Volume11
Issue number3
StatePublished - 1997

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nephrons
proximal tubules
Nephrons
Depolarization
Baths
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
HEPES
buffering capacity
fluorescent dyes
Fluorescent Dyes
potassium channels
Buffers
transporters
Chickens
Permeability
permeability
buffers
Fluxes
Membranes
kidneys

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

Cite this

Regulation of intracellular pH (pHi) in proximal tubules of avian loopless reptilian-type nephrons. / Martinez, C. L.; Brokl, O. H.; Shuprisha, A.; Abbott, D. E.; Dantzler, William H.

In: FASEB Journal, Vol. 11, No. 3, 1997.

Research output: Contribution to journalArticle

Martinez, C. L. ; Brokl, O. H. ; Shuprisha, A. ; Abbott, D. E. ; Dantzler, William H. / Regulation of intracellular pH (pHi) in proximal tubules of avian loopless reptilian-type nephrons. In: FASEB Journal. 1997 ; Vol. 11, No. 3.
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abstract = "We examined pHi and its regulation in isolated nonperfused proximal tubules of chicken loopless nephrons (70-90{\%} of nephrons in kidney) using pH-sensitive fluorescent dye BCECF. Under control conditions (HEPES buffer, pH 7.4; 37°C) resting pH was 7.18 ± 0.02 (mean ± SE). Addition of 20 mM NH4Cl to bath increased pH to 7.68 ± 0.03. Removal of NH4Cl from bath reduced pH to 6.95 ± 0.03. Rate of pHi change (dpHi/dt, pH U/s), intrinsic buffering capacity (βi, mM H+/pH U), basolateral NH3 flux (JNH3, nmol/cm2/s), and basolateral NH3 permeability (PNH3, cm/s × 10-3) were, respectively: 0.13 ± 0.01, 27.55 ± 3.42, 1.86 ± 0.16, and 3.80 ± 0.32. Control recovery rate (dpHi/dt) from acid pHi after NH4Cl removal was 4.98 ± 0.38 × 10-3 pH U/s. This dpHi/df was significantly (P < 0.05; paired studies) decreased by removal of Na+ (replacement with N-methyl-D-glucamine Cl-), simultaneous removal of Na+ and Cl- (replacement with N-methyl-D-glucamine-gluconate), or addition of DIDS, significantly increased by high K+ (75 mM) (depolarization of basolateral membrane); and unchanged by removal of Cl- (replacement with Na+-gjuconate) or addition of EIPA (1 mM) or Ba2+ (basolateral depolarization; blockage of K+ channels) Resting pH was significantly (P < 0.05; paired studies) decreased by Na+ removal or simultaneous Na+ and Cl- removal; significantly increased by high K+; and unchanged by Cl- removal alone or addition of Ba2+. Data do not fit concept of pHi regulation by usual basolateral transporters (Na+/H+ exchange; Na+-dependent and Na+-independent Cl- /HCO3- exchange; or Na+-HCO3--CO32- cotransporter). There may be Na--HCO3 cotransporter for basolateral HCO3- entry.",
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T1 - Regulation of intracellular pH (pHi) in proximal tubules of avian loopless reptilian-type nephrons

AU - Martinez, C. L.

AU - Brokl, O. H.

AU - Shuprisha, A.

AU - Abbott, D. E.

AU - Dantzler, William H

PY - 1997

Y1 - 1997

N2 - We examined pHi and its regulation in isolated nonperfused proximal tubules of chicken loopless nephrons (70-90% of nephrons in kidney) using pH-sensitive fluorescent dye BCECF. Under control conditions (HEPES buffer, pH 7.4; 37°C) resting pH was 7.18 ± 0.02 (mean ± SE). Addition of 20 mM NH4Cl to bath increased pH to 7.68 ± 0.03. Removal of NH4Cl from bath reduced pH to 6.95 ± 0.03. Rate of pHi change (dpHi/dt, pH U/s), intrinsic buffering capacity (βi, mM H+/pH U), basolateral NH3 flux (JNH3, nmol/cm2/s), and basolateral NH3 permeability (PNH3, cm/s × 10-3) were, respectively: 0.13 ± 0.01, 27.55 ± 3.42, 1.86 ± 0.16, and 3.80 ± 0.32. Control recovery rate (dpHi/dt) from acid pHi after NH4Cl removal was 4.98 ± 0.38 × 10-3 pH U/s. This dpHi/df was significantly (P < 0.05; paired studies) decreased by removal of Na+ (replacement with N-methyl-D-glucamine Cl-), simultaneous removal of Na+ and Cl- (replacement with N-methyl-D-glucamine-gluconate), or addition of DIDS, significantly increased by high K+ (75 mM) (depolarization of basolateral membrane); and unchanged by removal of Cl- (replacement with Na+-gjuconate) or addition of EIPA (1 mM) or Ba2+ (basolateral depolarization; blockage of K+ channels) Resting pH was significantly (P < 0.05; paired studies) decreased by Na+ removal or simultaneous Na+ and Cl- removal; significantly increased by high K+; and unchanged by Cl- removal alone or addition of Ba2+. Data do not fit concept of pHi regulation by usual basolateral transporters (Na+/H+ exchange; Na+-dependent and Na+-independent Cl- /HCO3- exchange; or Na+-HCO3--CO32- cotransporter). There may be Na--HCO3 cotransporter for basolateral HCO3- entry.

AB - We examined pHi and its regulation in isolated nonperfused proximal tubules of chicken loopless nephrons (70-90% of nephrons in kidney) using pH-sensitive fluorescent dye BCECF. Under control conditions (HEPES buffer, pH 7.4; 37°C) resting pH was 7.18 ± 0.02 (mean ± SE). Addition of 20 mM NH4Cl to bath increased pH to 7.68 ± 0.03. Removal of NH4Cl from bath reduced pH to 6.95 ± 0.03. Rate of pHi change (dpHi/dt, pH U/s), intrinsic buffering capacity (βi, mM H+/pH U), basolateral NH3 flux (JNH3, nmol/cm2/s), and basolateral NH3 permeability (PNH3, cm/s × 10-3) were, respectively: 0.13 ± 0.01, 27.55 ± 3.42, 1.86 ± 0.16, and 3.80 ± 0.32. Control recovery rate (dpHi/dt) from acid pHi after NH4Cl removal was 4.98 ± 0.38 × 10-3 pH U/s. This dpHi/df was significantly (P < 0.05; paired studies) decreased by removal of Na+ (replacement with N-methyl-D-glucamine Cl-), simultaneous removal of Na+ and Cl- (replacement with N-methyl-D-glucamine-gluconate), or addition of DIDS, significantly increased by high K+ (75 mM) (depolarization of basolateral membrane); and unchanged by removal of Cl- (replacement with Na+-gjuconate) or addition of EIPA (1 mM) or Ba2+ (basolateral depolarization; blockage of K+ channels) Resting pH was significantly (P < 0.05; paired studies) decreased by Na+ removal or simultaneous Na+ and Cl- removal; significantly increased by high K+; and unchanged by Cl- removal alone or addition of Ba2+. Data do not fit concept of pHi regulation by usual basolateral transporters (Na+/H+ exchange; Na+-dependent and Na+-independent Cl- /HCO3- exchange; or Na+-HCO3--CO32- cotransporter). There may be Na--HCO3 cotransporter for basolateral HCO3- entry.

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