Characteristic motor patterns of phase II and behaviour of phase III in the fed state

Abstract

The motor pattern of the phase II of the migration motor complex (MMC) is poorly characterized and it remains to be determined whether it differs from the fed motor-pattern. Furthermore, discrepancy exists on the disruption of ongoing MMCs by feeding, and finally, the understanding of the behaviour of phase Ills during enteral nutrition is incomplete. Therefore, canine intestinal motility was studied after meal and during enteral infusion of nutrients (elemental diet, glucose, maltose, amino acids) or of hypertonic saline (300–1520 mosmol kg−1). Motility of the proximal, mid- and distal jejunum was recorded with strain-gauge transducers. The motor patterns of the interdigestive phase II, after feeding and during enteral nutrition were analysed by a computer. Additionally, the disruption of the MMC by food and by enteral infusion of nutrients or hypertonic saline was investigated. The inter digestive phase II consisted of three different contractile patterns, clustered contractions, a mixed contractile pattern and non-migrating bursts of propagated contractions (NBPCs). NBPCs differed significantly from the phase III activity in several motility parameters and by the lack of aboral migration. Only small differences existed between the motor patterns of phase II and of the fed state, whereas the motor pattern induced by enteral infusion of an elemental diet differed significantly from that of phase II. Ongoing MMCs of the proximal jejunum often continued to migrate to the mid- and distal jejunum. During enteral infusion of nutrients or of hypertonic saline, phase Ills recurred. The migration of ongoing phase Ills and the recurrence of subsequent phase Ills decreased with increasing caloric or osmotic loads. The following conclusions were reached, (a) The phase II of the MMC is a complex motor-pattern. NBPCs represent a new contractile pattern, (b) The MMC is a characteristic feature of the empty gut. After meal and during enteral nutrition, phase Ills are usually suppressed but they can recur during the digestive period.