Human postprandial gastric emptying of indigestible solids can occur unrelated to antral phase III.

According to animal experiments, postprandial gastric emptying of indigestible solids is mainly related to the antral phase III activity of the migrating motor complex. Gastric emptying of indigestible solids in humans has not been directly correlated to pressure recordings. The aim of the present study was to investigate the postprandial emptying pattern of indigestible solids in humans and its relation to fed and fasted antral motility. Ten healthy volunteers participated. After an overnight fast they had a standard breakfast. Two sizes of radiopaque markers (ROMs) were given with the test meal; ten cubes each of side measurement 1.5 mm and 3 mm, respectively. Emptying of the ROMs from the stomach was followed by fluoroscopy with simultaneous antral manometry. In six of the subjects, fasting antral manometry was performed on one day and on another day, the emptying of 7 mm cylindrical particles together with 3 mm cubes, in the absence of a gastric tube was recorded. All ROMs were emptied within 5 h (range 1.5-4.5 h). In all subjects, the smaller particles (1.5 mm) showed a slight, insignificant tendency to move from the stomach more rapidly than the larger (3 mm) particles. None of the subjects had an antral phase III before all ROMs were emptied from the stomach. Instead, the typical irregular postprandial pressure activity was present in all subjects until the emptying was completed. Furthermore, the highest postprandial motility index during the emptying study was far below the motility index during phase III, but comparable to the motility index during late phase II. Emptying of the 7 mm particles occurred significantly more slowly at 1.5-2.5 h, but otherwise was similar to the emptying of the smaller particles. There was no difference between emptying of the 3 mm cubes with or without the presence of the tube. Contrary to common opinion, gastric emptying of indigestible solids after a meal can occur unrelated to the antral phase III, at least up to a particle size of 3 mm and perhaps even 7 mm. These findings are of great importance for the evaluation of gastric emptying of indigestible solids, including the pharmacodynamics of orally administered drugs.