Tracheal epithelial permeability to nonelectrolytes: Species differences

O. D. Wangensteen, L. A. Schneider, S. C. Fahrenkrug, G. M. Brottman, R. C. Maynard

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

We developed a new excised tracheal preparation to measure the epithelial permeability of large lipid-insoluble nonelectrolytes and macromolecules. Tracheae were suspended vertically in a Ringer solution bath, and a solution containing labeled test solutes was positioned in the center of the tracheal segment, away from damaged ends. Permeability coefficients, calculated from solute fluxes into the bath, were constant for ≥2 h at 37°C, and no histological changes were observed. Measurements after epithelial removal with detergent indicate that in the intact trachea the epithelium represents >90% of the resistance to transport. For the rat trachea, permeability coefficients for sucrose, inulin, and Dextran 20 were 9.22, 2.20, and 0.214 x 10-7 cm/s, respectively. Values for cat tracheae were similar, those for rabbit tracheae were lower, and those for guinea pig tracheae were markedly greater. With the assumption of transport by diffusion through thin rectangular slits between epithelial cells, the rat and guinea pig data fit a slit width of 7-8 nm, whereas the rabbit and cat data cannot be explained by a model with slits of a single size.

Original languageEnglish (US)
Pages (from-to)1009-1018
Number of pages10
JournalJournal of applied physiology
Volume75
Issue number2
DOIs
StatePublished - 1993

Keywords

  • Dextran 20
  • cat
  • equivalent slit width
  • guinea pig
  • inulin
  • rabbit
  • rat
  • sucrose

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