Related Experiment Video
Updated: Jun 24, 2026

Catheterization of Intestinal Loops in Ruminants
Published on: June 11, 2009
The enterotoxic effect of zonula occludens toxin on rabbit small intestine involves the paracellular pathway
1Division of Pediatric Gastroenterology and Nutrition, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, USA.
Background & Aims:
Zonula occludens toxin is a novel toxin elaborated by Vibrio cholerae that modulates intestinal tight junctions. The aim of this study was to establish whether the permeabilizing effect of the toxin leads to intestinal secretion.
Methods:
Rabbit intestine was mounted in Ussing chambers and exposed to increasing concentrations of purified toxin. The tissues were also fixed, exposed to zonula occludens toxin, and processed for fluorescence microscopy to determine the distribution of the toxin receptor within the intestine. Then purified toxin was simultaneously perfused in three distinct rabbit intestinal segments in vivo, and water and electrolyte absorption were measured.
Results:
Zonula occludens toxin induced a time- and dose-dependent decrease of tissue resistance starting at a toxin concentration of 1.1 x 10(-13) mol/L. When tested in vivo, the toxin induced a secretion of water and chloride and the passage of polyethylene glycol 4000 in the bloodstream. Both the in vitro and in vivo effects of the toxin were observed only in the small intestine but not in the colon and paralleled the distribution of the toxin receptor within the intestine.
Conclusions:
The intestinal secretion induced by zonula occludens toxin follows the opening of tight junctions caused by the toxin, possibly representing a novel mechanism of intestinal secretion.
More Related Videos
Related Concept Videos
Tight Junctions
Renewal of Intestinal Stem Cells
Histology of the Small Intestine
The intestinal lining features transverse folds called circular folds, each housing fingerlike projections known as intestinal villi. These villi are covered by a layer of simple columnar epithelium, also referred to as...
Bacterial Gastroenteritis
Amebiasis
Intestinal Obstruction II: Pathophysiology

