The effect of gastric overfilling on the pharyngo-esophageal and lower esophageal sphincter: A possible factor in restricting food intake
Ahmed Shafik, Ali A Shafik, Olfat El Sibai, Ismail A Shafik
Med Sci Monit 2007; 13(10): BR220-224
Available online: 2007-10-01
&amp; &alpha; Background: How afferent activity in the gut achieves the required ingestion control has not been established. The authors hypothesized that gastric overdistension effects an increase in pharyngo-esophageal and lower esophageal sphincter activity aimed at inhibiting ingestion.
Material/Methods: The study comprised 16 mongrel dogs. Under anesthesia, one balloon-tipped catheter was placed in the stomach, another within the lower esophageal sphincter (LES), and a third within the pharyngo-esophageal sphincter (PES). The gastric balloon was filled with H[sub]2[/sub]O in increments of 10 ml and LES and PES pressures were recorded. The test was repeated after individual gastric, LES, and PES anesthetization.
Results: Gastric balloon filling with more than 20 ml of H[sub]2[/sub]O showed progressively increasing LES pressure up to 110–120 ml of gastric filling, beyond which the pressure exhibited no further increase upon incrementally increased gastric filling volume. PES pressure increased only with a gastric filling volume exceeding 100–110 ml and continued to increase with increasing gastric filling. Gastric filling as above while the stomach, LES, and PES were separately anesthetized produced no LES or PES pressure response.
Conclusions: LES and PES appear to contract on gastric filling; PES responds only to excess gastric filling. It seems that LES and PES response to gastric filling is mediated through a reflex which the authors call the "gastro-esophagopharyngeal reflex" (GEPR). Changes in the evoked response would indicate a defect in the reflex pathway. GEPR might thus serve as an investigative tool in the diagnosis of gastroesophageal disorders, although further studies are required.
Keywords: Dogs, Catheterization, Animals, Esophageal Sphincter, Lower - physiopathology, Feeding Behavior - physiology, Pharynx - physiology, Pressure, Stomach - physiology, Water