Effects of gastrointestinal hormones on Oddi's sphincter and duodenal myoelectric activity and pancreatobiliary pressure. Studies in the opossum.

Myoelectric activity of Oddi's sphincter and duodenum was correlated with common duct and pancreatic duct pressures in conscious opossums after infusion of the following substances: cholecystokinin, pentagastrin, glucagon, secretin, and acetylcholine. Cholecystokinin and pentagastrin increased and glucagon and secretin decreased the frequency of spike potentials in Oddi's sphincter and the duodenum. Acetylcholine was associated with the largest increase in spike potentials in both Oddi's sphincter and the duodenum. Although there was variation in the number of pressure elevations related to Oddi's sphincter spike potentials, the baseline pressure remained constant during administration of the hormones. Acetylcholine infusion increased the biliary and pancreatic pressures to 29 and 31 mm Hg, respectively. We conclude that gastrointestinal hormones may have an important role in regulating the excretion of bile and pancreatic juice into the duodenum.