Interdigestive Migrating Contraction in Short Bowel Dogs

Extraluminal force transducers were chronically implanted onto the serosal surface of the gastrointestinal tract in dogs and the interdigestive migrating contractions (IMC) were studied in conscious dogs. When the IMC occurring periodically in the stomach reaches the distal ileum, the next IMC develops in the stomach. We therefore studied the effect of isolation or resection of the lower third of the small bowel on the periodic occurrence of IMC in the stomach. Transducers were sutured onto the antrum, the upper jejunum, the mid intestine and the terminal ileum. After control records on gastrointestinal motility were made for these dogs, the abdominal cavity was again opened to prepare a Thiry loop in the lower third of the small bowel. (isolation group) Next, the loop was removed (resection group) and gastrointestinal motility was recorded. In these groups, we 1) measured the time from the feeding to the initiation of the first IMC. 2) measured the time from the termination of one IMC to the termination of the next IMC. 3) measured the migrating time of the IMC. 4) and measured the duration of the IMC in the stomach. As a result, it was found that the time interval between the termination of one IMC in the stomach and the termination of the next was almost constant throughout all experiments. The migrating time of the IMC from the stomach to the terminal ileum in isolation and resection groups was slightly shortened. These findings indicate that the existence of the lower gut has no significant influence upon the regular periodic occurrence of the IMC in the stomach and the migrating time.