The role of the extrinsic antral nerves in the regulation of gastric emptying.

In six conscious dogs with chronically implanted gastric and duodenal electrodes, gastric emptying of 40 radiopaque plastic spheres, with a diameter of 7 millimeters and a specific gravity of 1.6, was assessed fluoroscopically during fasting and after the feeding of the 25 grams of 1 centimeter cubes of boiled beef liver. Gastric emptying of 400 milliliters of 154 millimolar sodium chloride marked with 14C PEG was also measured. The extrinsic antral nerves were then transected, and after recovery, the tests were repeated. Before antral denervation, gastric spheres were emptied predominantly during activity fronts--the five to 15 minute bursts of action potentials and contractions that sweep aborally from the stomach to the colon every two hours during fasting. Feeding abolished activity fronts for about eight hours and, therefore, delayed gastric emptying of the spheres. After antral denervation, antral activity fronts were irregular, less frequent and of shorter duration, and the spheres emptied slower both during fasting and after feeding. In contrast, the emptying of isotonic sodium chloride was unchanged. We concluded that antral extrinsic nerves enhance gastric emptying of solid spheres but not of isotonic sodium chloride.