Nystatin as a probe for investigating the electrical properties of a tight epithelium

• Type of Material: Article
• Authors: Simon A. Lewis, University of Texas Galveston; Douglas Eaton, Emory University; Chris Clausen, University of Texas Galveston; Jared M. Diamond, University of Texas Galveston
• Language: English
• Date: 1977-01-01
• Publisher: Rockefeller University Press
• Publication Version: Final Published Version
• Copyright Statement: © 1977 Rockefeller University Press
• License: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1085/jgp.70.4.427
• Title of Journal or Parent Work: Journal of General Physiology
• Volume: 70
• Issue: 4
• Start Page: 427
• End Page: 440
• Keywords: Science & Technology; Physiology; Life Sciences & Biomedicine

Abstract

The authors show how the antibiotic nystatin may be used in conjunction with microelectrodes to resolve transepithelial conductance G(t) into its components: G(a), apical membrane conductance; G(bl), basolateral membrane conductance; and G(j), junctional conductance. Mucosal addition of nystatin to rabbit urinary bladder in Na+-containing solutions caused G(t) to increase severalfold to ca. 460 μmho/μF, and caused the transepithelial voltage V(t) to approach +50 mV regardless of its initial value. From measurements of G(t) and the voltage-divider ratio as a function of time after addition or removal of nystatin, values for G(a), G(bl), and G(j) of untreated bladder could be obtained. Nystatin proved to have no direct effect on G(bl) or G(j) but to increase G(a) by about two orders of magnitude, so that the basolateral membrane then provided almost all of the electrical resistance in the transcellular pathway. The nystatin channel in the apical membrane was more permeable to cations than to anions. The dose-response curve for nystatin had a slope of 4.6. Use of nystatin permitted assessment of whether microelectrode impalement introduced a significant shunt conductance into the untreated apical membrane, with the conclusion that such a shunt was negligible in the present experiments. Nystatin caused a hyperpolarization of the basolateral membrane potential in Na+-containing solutions. This may indicate that the Na+ pump in this membrane is electrogenic.