Related Experiment Video
Updated: Jul 9, 2026

Methods to Study Epithelial Transport Protein Function and Expression in Native Intestine and Caco-2 Cells Grown in 3D
Published on: March 16, 2017
Effects of luminal hyperosmolality on cellular and paracellular ion transport pathways in necturus antrum
Abstract:
Using microelectrode techniques, the electrical properties of the cell membranes and paracellular pathway of the surface epithelium in Necturus antrum were studied under control conditions and during exposure to mucosal solutions made hyperosmotic by addition of sucrose or urea. Sucrose (500 mmol/kg) significantly decreased apical membrane resistances (Ra, from 5501 +/- 841 to 3789 +/- 597 omega X cm2, p less than 0.01), and basolateral membrane resistances (Rb, from 3805 +/- 646 to 2594 +/- 429 omega X cm2, p less than 0.05). The paracellular pathway resistance (Rs) increased significantly from 720 +/- 57 to 822 +/- 71 omega X cm2 (p less than 0.001). Urea (500 mmol/kg) more markedly diminished the apical and basolateral resistances (Ra, from 4303 +/- 663 to 1914 +/- 286 omega X cm2, p less than 0.001; and Rb, from 2600 +/- 474 to 1034 +/- 213, p less than 0.001). In contrast to sucrose, urea-containing solutions significantly decreased Rs (from 682 +/- 78 to 398 +/- 57 omega X cm2, p less than 0.001). Electron micrographs revealed dilatation of lateral intercellular spaces and disruption of desmosomes in tissues exposed to urea, but no visible alterations in tissues exposed to solutions containing sucrose. The resistance of the cellular pathway to ion permeation was thus diminished during exposure to both solutes. In contrast, changes in resistance of the paracellular pathway appeared to depend on the effects of each solute on dimensions and structures of the intercellular pathways.
More Related Videos
Related Concept Videos
Osmosis
Transcellular Transport of Solutes
Osmosis
Water, like other substances, moves from a high concentration of free water...
Reabsorption and Secretion in the Loop of Henle
Reabsorption and Secretion in the DCT and Collecting Duct
The distal part of the DCT, along with the...
Physiology of the Genitourinary System II: Tubular Reabsorption and Secretion

