Regulation of intracellular pH in proximal tubules of avian long-looped mammalian-type nephrons

Olga H. Brokl, Christina L. Martinez, Apichai Shuprisha, Diane E. Abbott, William H Dantzler

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Abstract

In nonperfused proximal tubules isolated from chicken long-looped mammalian-type nephrons, intracellular pH (pH(i)), measured with the pH- sensitive fluorescent dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, was ~7.3 under control conditions (HEPES-buffered medium with pH 7.4 at 37°C) and was reduced to ~7.0 in response to NH4Cl pulse. The rate of recovery of phi from this level to the resting level was 1) significantly reduced by the removal of Na+ from the bath, 2) significantly increased by the removal of Cl- from the bath, 3) unchanged by the removal of both Na+ and Cl- from the bath, 4) significantly reduced by the addition of either ethylisopropylamiloride or DIDS to the bath, 5) significantly increased by a high bath K+ concentration, and 6) unchanged by the addition of Ba2+ to the bath. These data suggest that both Na+-coupled and Cl--coupled basolateral acid-base fluxes are involved in determining the rate of recovery of phi after acidification. The most likely ones to be important in regulating phi are a Na+/H+ exchanger and a Na+-coupled Cl-/HCO3/- exchanger. In birds, long-looped mammalian-type nephrons resemble short- looped transitional nephrons but differ markedly from superficial loopless reptilian-type nephrons.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume274
Issue number6 43-6
Publication statusPublished - 1998

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Keywords

  • Ammonium chloride pulse
  • Chickens
  • Chloride- coupled basolateral acid-base fluxes
  • Intracellular acidification
  • Intrinsic buffering capacity
  • Sodium-coupled basolateral acid-base fluxes

ASJC Scopus subject areas

  • Physiology

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