Effect of gastric distension and duodenal fat infusion on biliary sphincter of oddi motility in healthy volunteers

Although sphincter of Oddi (SO) dysfunction has been implicated in the pathogenesis of postcholecystectomy syndrome and pancreatitis, little is known about normal physiologic stimuli, such as intraduodenal fat on human SO motility. Furthermore, gastric distension that frequently accompanies endoscopic manometry has been shown in animal studies to affect SO motility. We evaluated the effects of intraduodenal fat and gastric distension on SO basal pressure. Asymptomatic volunteers had SO manometry performed while sequentially performing gastric distension and intraduodenal fat perfusion. Five subjects (ages 29.8±4.8 years, range 22-35 years) had a mean basal sphincter of Oddi pressure of 23.4±5 mm Hg (range 17-31 mm Hg). Injection of air into the stomach caused no appreciable change in either intragastric pressure or SO pressure. Intraduodenal fat infusion resulted in a decrease in mean SO basal pressure from 23.4±5.0 to 4.4±4.4 mm Hg (P=0.004). These results demonstrate that gastric distension does not affect SO basal pressure and that intraduodenal fat infusion reduces SO basal pressure.