Conductive properties of papillary surface epithelium

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4 Scopus citations

Abstract

The surface epithelium of rabbit renal papilla was dissected free from its supporting tissue and mounted in an Ussing chamber. The conductive properties of the epithelium and of the apical and basolateral cell membranes were examined with KCl-filled microelectrodes. The transepithelial voltage was 0.07 ± 0.15 mV, and the transepithelial resistance was 107 ± 15 Ω·cm2 (n = 29). The fractional resistance of the apical membrane (fRa) was 0.93 ± 0.01 (n = 103 cells, 29 tissues). The apical membrane was not conductive to Na+, K+, or Cl-. An increase in the K+ concentration of the basolateral solution from 5 to 50 mM depolarized the basolateral membrane voltage (Vb) from -59 ± 1.6 to -31.2 ± 2.2 mV (n = 28 cells) and increased fRa from 0.935 ± 0.01 to 0.962 ± 0.01 (P < 0.001, n = 21 cells). Likewise, 5 mM barium in the basolateral solution depolarized Vb from -57.7 ± 2.0 to -29.8 ± 2.2 mV (n = 21 cells). A tenfold decrease in the Cl- concentration of the basolateral solution caused an 8.3 ± 1.9 mV depolarization in Vb. Thus the basolateral cell membrane is conductive to K+ and Cl-. Exposure of the apical membrane to amphotericin B demonstrated that the transepithelial resistance is determined primarily by the paracellular pathway.

Original languageEnglish (US)
Pages (from-to)F259-F265
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume266
Issue number2 35-2
DOIs
StatePublished - Feb 1994
Externally publishedYes

Keywords

  • Barium
  • Chloride
  • Electrophysiology
  • Intracellular microelectrode
  • Ion transport
  • Potassium
  • Renal papilla
  • Sodium

ASJC Scopus subject areas

  • Physiology

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