Related Experiment Video
Updated: Jul 18, 2026

Mucin Agarose Gel Electrophoresis: Western Blotting for High-molecular-weight Glycoproteins
Published on: June 14, 2016
Central vagal activation increases mucus gel thickness and surface cell intracellular pH in rat stomach
1West Los Angeles Veterans Administration Medical Center, CURE: Digestive Diseases Research Center, Department of Medicine, California, USA.
Background & Aims:
Central vagal stimulation induced by the thyrotropin-releasing hormone analogue RX 77368 injected intracisternally in urethane-anesthetized rats is gastroprotective. In an in vivo system, the effects of central RX 77368 on discrete components of the rat gastric mucosal barrier were studied to determine if these effects were prostaglandin synthesis dependent.
Methods:
Using intravital microscopy, intracellular pH of gastric surface cells, mucus gel thickness, gastric mucosal blood flow, and acid output were measured simultaneously in vivo.
Results:
Intracisternal RX 77368 significantly increased acid output, gel thickness, and blood flow. Indomethacin enhanced the RX 77368-induced increase in acid output but had no effect on measures of gastric defense during mucosal superfusion with neutral solutions. During acid superfusion, RX 77368 delayed acidification and enhanced recovery of surface cell intracellular pH. These latter effects were reversed partially by indomethacin. Omeprazole abolished RX 77368-induced acid secretion but did not alter its effects on gastric defense mechanisms.
Conclusions:
In response to central vagal stimulation with RX 77368, gastric defense mechanisms were enhanced through prostaglandin-dependent and -independent pathways, in contrast to the prostaglandin-independent effects of intravenous pentagastrin. RX 77368-induced enhancements of gastric defense mechanisms did not occur as a result of acid secretion.
Related Concept Videos
Stomach pH Regulation
The acid-secreting gastric mucosal epithelial cells (parietal cells) lining the stomach lumen maintain the low pH in the lumen. Numerous ion transporters and channels on these parietal...
Pathophysiology of Peptic Ulcer Disease: Injurious Factors
In the antrum region, G cells secrete the gastrin hormone that binds to gastrin-cholecystokinin-B (CCK2) receptors on parietal and enterochromaffin-like (ECL) cells in the fundic glands. Simultaneously, the vagus nerve releases acetylcholine, which binds to M3...
Cephalic Phase of Digestion
Gastric Phase of Digestion
When food enters the stomach, it stretches the stomach walls and activates stretch receptors. This triggers local reflexes of the enteric nervous system, mediated through the myenteric plexus. These...
Intestinal Phase of Digestion
The arrival of the chyme in the small intestine distends the duodenum, which triggers the enterogastric reflex. This distension...
Mucosal Barrier of the Stomach
Within parietal cells, carbonic acid is first formed through the reaction of water and carbon dioxide. The dissociation of carbonic acid releases bicarbonate and hydrogen ions. The bicarbonate...

