Nonmigrating rhythmic activity in the stomach and duodenum of neonates.

We studied gastrointestinal motility in 20 infants, using a modified manometric method for neonates, and compared it to that in adults. Changes in the intragastric and intraduodenal pressures were recorded for 3 h after the ingestion of milk. Bands of contractions with the same rhythmicity as phase III activity in adults were frequently recorded. Some of them migrated caudally and were speculated to the equivalent of phase III activity of the interdigestive migrating complex (IMC) in adults. However, others did not migrate and showed some differences from phase III activity of adults and infants in the time of occurrence, duration and amplitude. The characteristic of gastroduodenal motility in infants was the frequent occurrence of these bands of nonmigrating rhythmic concentrations. Our findings indicated the following problems: (1) there are some differences in gastrointestinal motility between infants and adults and further investigations are required for the evaluation of the physiology or pathophysiology of this phenomenon; (2) in infants, many bands of rhythmic contractions of the alimentary tracts can exist without migration. This indicates the possibility that the occurrence of rhythmic contractions and their migration are regulated by different mechanisms.