Low permeabilities of apical membranes of barrier epithelia: what
makes water-tight membranes water-tight?.
Zeidel, Mark L.
Laboratory of Epithelial Cell Biology, Renal-Electrolyte Division,
University of Pittsburgh Medical Center, 937 Scaife Hall, 3550
Terrace Street, Pittsburgh, PA 15213
APStracts 3:0090F, 1996.
Barrier epithelia separate compartments of widely differing
composition and prevent the passage between compartments of
substances like water, urea, protons, and ammonia, which are normally
highly permeant across biological membranes (see Table). Because the
apical membranes of the epithelial cells represent the major barrier
to permeation, understanding how barrier epithelia function requires
an understanding of how their apical membranes can be constructed so
as to limit permeability (5,17,22,13). Failure of these barrier
apical membranes can lead to significant human disease, including
ulcer disease of the stomach, cystitis in the bladder and failure of
urinary concentration, dilution and acidification in the distal
nephron.
Received 7 May 1996; accepted in final form 8 May 1996.
APS Manuscript Number F138-6.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 May 96