Cytoplasmic regulation of tight-junction permeability: effect of plant cytokinins

The significance of the "leaky" tight junction might be understood better if cells of the epithelial monolayer possessed mechanisms to regulate molecular flow through the junction. To test this possibility, Necturus gallbladder, a representative leaky epithelium, was studied before, during...

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Bibliographic Details
Published inThe American journal of physiology Vol. 239; no. 3; p. C75
Main Authors Bentzel, C J, Hainau, B, Ho, S, Hui, S W, Edelman, A, Anagnostopoulos, T, Benedetti, E L
Format Journal Article
LanguageEnglish
Published United States 01.09.1980
Subjects
Animals
Cytochalasin B - pharmacology
Cytokinins - pharmacology
Dose-Response Relationship, Drug
Electric Conductivity
Gallbladder - physiology
In Vitro Techniques
Intercellular Junctions - physiology
Membrane Potentials - drug effects
Necturus
Phalloidine - pharmacology
Plant Growth Regulators - pharmacology
Purines - pharmacology
Time Factors
Zeatin - pharmacology
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Summary:The significance of the "leaky" tight junction might be understood better if cells of the epithelial monolayer possessed mechanisms to regulate molecular flow through the junction. To test this possibility, Necturus gallbladder, a representative leaky epithelium, was studied before, during, and after mucosal exposure to plant cytokinins and two other microfilament-active drugs, cytochalasin B and phalloidin. Concomitant with morphological changes in microfilaments, cytokinins induced rapid reversible increases in transepithelial resistance and potential difference (PD) and decreases in NaCl dilution potentials, with no change in the ratio of relative cell membrane resistances. Cytochalasin B (0.2-1.2 microM) and phalloidin (0.6-12.7 microM) caused similar changes in transepithelial resistance and PD. When the intramembranous structure of tight junctions was studied by freeze fracture, peak cytokinin-induced increments in transepithelial resistance were associated with more disorder in the strand meshwork resulting in a small increase in tight junction depth, but there was no evidence of de novo strand assembly. These studies suggest that permeability of the tight junction of Necturus gallbladder is subject to rapid reversible modulation, possibly under cytoskeletal control.
ISSN:0002-9513
DOI:10.1152/ajpcell.1980.239.3.c75