Response of migrating motor complex to variation of fasting intraluminal content.
The characteristics of the phases of the migrating motor complex (MMC) were studied in the antrum, duodenum, and jejunum after alteration of intraluminal gas and acaloric fluid in 17 healthy volunteers. Aspiration of gas and fluid from the upper gastrointestinal tract reduced motor activity. In the antrum and duodenum, phase II contraction amplitude decreased, while in the duodenum and jejunum, the duration of phase II decreased and phase I increased. Phase III contraction frequency decreased in the duodenum only. Intragastric instillation of gas caused an increase of phase II duration and contraction amplitude in all regions. Similar effects were observed after intragastric instillation of fluid. Fasting periodic motor activity is responsive to volume changes of intraluminal gas and acaloric liquid content.