Related Experiment Video
Updated: Aug 8, 2026
07:42
Improved Swiss-rolling Technique for Intestinal Tissue Preparation for Immunohistochemical and Immunofluorescent Analyses
Published on: July 13, 2016
Villus and crypt electrolyte and fluid transport during intestinal secretion
1Department of Pharmacology, Smith, Kline & French Laboratories, Philadelphia, PA.
Acta Physiologica Scandinavica
|May 1, 1990
Summary
Intestinal villi maintain sodium and chloride gradients during secretion, similar to absorption. This indicates unimpaired villus tip function and sufficient electrolyte supply for gradient formation during intestinal secretion.
Area of Science:
- Gastroenterology
- Physiology
- Cell Biology
Background:
- Apical jejunal villi exhibit sodium chloride gradients linked to water absorption.
- The presence and nature of these gradients during intestinal secretion remain unclear.
Purpose of the Study:
- To investigate sodium and chloride concentration gradients in jejunal villi during states of net intestinal secretion.
- To determine if these gradients differ between absorptive and secretive intestinal states.
Main Methods:
- Jejunal segments from anesthetized cats were perfused with modified Krebs-Henseleit solutions.
- Intestinal secretion was induced using cholera toxin or vasoactive intestinal polypeptide (VIP).
- Segments were freeze-dried, and sodium and chloride content in villi lamina propria were analyzed using X-ray microanalysis.
Main Results:
- A sodium and chloride concentration gradient was observed in the apical villus when the lumen contained sodium, irrespective of secretion or absorption.
- No gradient was found when the intestine was perfused with a hypotonic choline-mannitol solution.
- Secretagogues induced an apical gradient in the hypotonic solution, demonstrating unimpaired villus tip absorptive function.
Conclusions:
- The absorptive function of the jejunal villus tip is maintained during net intestinal secretion.
- Secreted electrolytes are sufficient to form apical concentration gradients, even during secretion.
More Related Videos
11:27Methods to Study Epithelial Transport Protein Function and Expression in Native Intestine and Caco-2 Cells Grown in 3D
Published on: March 16, 2017
06:43Functional Assessment of Intestinal Tight Junction Barrier and Ion Permeability in Native Tissue by Ussing Chamber Technique
Published on: May 26, 2021
Related Concept Videos
01:23Transcellular Transport of Solutes
Transcellular transport of solutes is the movement of substances like monosaccharides and amino acids through polarized cells. This transport mechanism is primarily seen in epithelial and endothelial cells aided by membrane transport proteins such as channels and transporters. The tight junctions between these cells confine the membrane proteins to the two sides of the cell. The epithelial cells have distinct apical and basolateral domains. In contrast, the endothelial cells show the luminal...
01:27Mineral, Vitamin and Water Absorption
Electrolytes are essential minerals and ions primarily obtained from the diet and absorbed through the gastrointestinal tract. Most electrolytes are absorbed in the small intestine. While the absorption of iron and calcium primarily occurs in the duodenum, calcium is also absorbed in the jejunum and ileum. In these regions, passive diffusion contributes to its absorption alongside active transport mechanisms in the duodenum. These ions can exit the enterocytes through specialized active...
01:28Reabsorption and Secretion in the PCT
The Proximal Convoluted Tubule, or PCT, plays a pivotal role in the body's filtration system. They are primarily responsible for reabsorbing solutes and water from the filtered fluid produced by the glomeruli. Most of the filtered water, ions, and organic solutes such as glucose and amino acids are reabsorbed by the PCT.
Transport mechanisms involving sodium ions (Na+) contribute significantly to solute reabsorption. These mechanisms include symport and antiport processes.
A key example is the...
Transport mechanisms involving sodium ions (Na+) contribute significantly to solute reabsorption. These mechanisms include symport and antiport processes.
A key example is the...
01:17Reabsorption and Secretion in the Loop of Henle
The thick ascending limb of the nephron loop has Na+–K+–2Cl− symporters in the apical membranes of its cells. These symporters simultaneously reclaim one sodium ion, one potassium ion, and two chloride ions from the tubular fluid. Sodium ions are actively transported into the interstitial fluid at the base and sides of the cell, diffusing into the vasa recta. Chloride ions move through leakage channels in the basolateral membrane into the interstitial fluid and then into the vasa recta.
01:26Reabsorption and Secretion in the DCT and Collecting Duct
The early phase of the DCT manages the reabsorption of approximately 10-15% of filtered water, 5–10% of filtered sodium, and 5–10% of filtered chloride. This process is facilitated by Na+–Cl− symporters in apical membranes and sodium-potassium pumps, as well as Cl− leakage channels in basolateral membranes. The early DCT also stands out as a site where parathyroid hormone (PTH) stimulates calcium reabsorption, depending on the body's requirements.
The distal part of the DCT, along with the...
The distal part of the DCT, along with the...
01:19Absorption of Nutrients
Absorption refers to taking dietary nutrients from the intestinal lumen for transportation throughout the body. After digestion in the small intestine, carbohydrates, proteins, and fats are broken down into simpler forms. These essential macronutrients and other vital substances, such as vitamins, minerals, and water, are then prepared for absorption into the bloodstream.
Enterocytes, which are specialized polar epithelial cells, line the mucosa of the small intestinal walls. These cells...
Enterocytes, which are specialized polar epithelial cells, line the mucosa of the small intestinal walls. These cells...