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Canine gastric muscarinic receptors up-regulate after vagotomy
A Keshavarzian1, T B Steck, D Conway
1Department of Medicine, Loyola University Medical School, Maywood, Illinois 60153.
Abstract:
Postvagotomy (PV) gastroparesis is an infrequent but troublesome problem. To test the hypothesis that the rarity of the PV syndrome is due to compensatory up-regulation of muscarinic cholinergic receptors (mAChR), we measured changes in stomach mAChR and gastric acid secretion in dogs before and three weeks after truncal vagotomy. Maximum acid output dropped significantly one week PV and then partially recovered by three weeks PV. mAChR density changed in parallel and was significantly increased in body mucosa, body muscle, and antrum mucosa. In the body, changes in mAChR in mucosa correlated positively with changes in muscle, suggesting that mAChR binding in pinch biopsies of gastric mucosa might become useful in evaluating patients for postvagotomy syndrome. PV up-regulation of mAChR in the mucosa of the canine gastric body might explain PV recovery of gastric acid secretion.
Insights
Postvagotomy gastroparesis may be rare due to compensatory increases in muscarinic cholinergic receptors (mAChR). These receptor changes in dogs correlated with the recovery of gastric acid secretion after vagotomy.
Area of Science:
- Gastroenterology
- Physiology
- Pharmacology
Background:
- Postvagotomy (PV) gastroparesis is a rare but significant complication.
- The underlying mechanisms for its rarity and potential recovery are not fully understood.
Purpose of the Study:
- To investigate the hypothesis that compensatory up-regulation of muscarinic cholinergic receptors (mAChR) contributes to the rarity of postvagotomy gastroparesis.
- To examine the relationship between mAChR changes and gastric acid secretion following vagotomy.
Main Methods:
- Truncal vagotomy was performed on dogs.
- Changes in stomach mAChR density and gastric acid secretion were measured before and three weeks after vagotomy.
- Correlations between mAChR levels in different gastric tissues and acid output were analyzed.
Main Results:
- Maximum gastric acid output significantly decreased one week post-vagotomy, with partial recovery by three weeks.
- mAChR density significantly increased in gastric body mucosa, body muscle, and antrum mucosa post-vagotomy.
- Changes in mAChR in gastric body mucosa positively correlated with changes in muscle tissue.
Conclusions:
- Up-regulation of mAChR in the canine gastric body mucosa may explain the recovery of gastric acid secretion after vagotomy.
- mAChR binding in gastric mucosal biopsies could potentially aid in evaluating patients for postvagotomy syndrome.