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

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

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

In proximal tubules isolated from chicken superficial loopless reptilian-type nephrons, intracellular pH (pH(i)), measured with pH-sensitive fluorescent dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, was ~7.1- 7.2 under control conditions (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered medium with pH 7.4 at 37°C), and was reduced to ~6.9 in response to NH4Cl pulse. The rate of recovery of phi (control value ≃ 5 x 10-3 pH U/s) from this acid level was 1) significantly decreased by removal of Na+ or both Na+ and Cl- from the bath or addition of 4,4'- diisothiocyanostilbene-2,2'-disulfonic acid (0.25 mM) to the bath, 2) significantly increased by high bath K+ (75 mM), and 3) unchanged by removal of Cl- alone from the bath or addition of ethylisopropylamiloride (1 mM) or Ba2+ (5 mM) to the bath. Resting pH(i) was 1) significantly decreased by Na+ or simultaneous Na+ and Cl- removal, 2) significantly increased by high K+, and 3) unchanged by Cl- removal alone or addition of Ba2+. The data do not fit the concept of pHi regulation by the most commonly suggested basolateral transporters (Na+/H+ exchanger, Na+ -dependent and Na+- independent Cl-/HCO3/- exchangers, or Na+-HCO3/- -CO3/2- cotransporter).

Original languageEnglish (US)
Pages (from-to)R1845-R1854
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume273
Issue number6 42-6
DOIs
StatePublished - 1997

Keywords

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

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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