Gastrosphincter of Oddi reflex.

Gastric distention is known to stimulate gallbladder contraction as well as gastric acid and pancreatic exocrine secretion by way of neural reflexes. Gallbladder distention, in turn, has been shown to affect sphincter of Oddi motility. Since gastric distention may accompany endoscopic or operative biliary manometry, we tested the hypothesis that gastric distention alters sphincter of Oddi motility. In the prairie dog model, gastric distention with acid (0.1 M hydrochloric acid, pH 1.3) and alkaline (10(-5) sodium hydroxide, pH 8.8) isotonic saline solutions both resulted in significant increases in sphincter of Oddi phasic wave frequency, amplitude, and motility index. Similarly, gallbladder pressure increased during both distention periods, thus confirming the previously described pylorocholecystic reflex. These responses were abolished by systemic pretreatment with atropine, suggesting that this reflex is cholinergically mediated. These data suggest the presence of a gastrosphincter of Oddi reflex whereby gastric distention stimulates sphincter of Oddi motility in the prairie dog. We conclude that gastric distention is an important variable to be controlled when performing endoscopic or operative sphincter of Oddi manometry.