SUMMARYThe aim of this study was to determine the mechanisms controlling gastric emptying of viscous meals. In four conscious dogs the antral, pyloric and duodenal activities were recorded with strain-gauge transducers and induction coils during gastric evacuation of an inert cellulose meal and of four nutrient meals containing mannitol, casein, glucose or oleic acid. Gastric emptying and the internal pyloric and duodenal diameters were measured from radiographs. The nutrients delayed gastric emptying and diminished to a various extent the antral and duodenal motility as well as the pyloric opening. The motility gradient between antral and duodenal activity showed no relationship to the emptying delay. The duodenal lumen was reduced and the propulsive contractions of the duodenum decreased while the segmental activity increased. The findings suggest that gastric emptying is controlled by (1) the depth of the antral waves, (2) the pyloric opening, (3) the receptive relaxation of the duodenum and (4) the type of the duodenal contractions. By contrast the sequence of the terminal antral contraction and the pyloric closure, as well as the co-ordination between pyloric and duodenal contractions, played no important role in regulating gastric emptying.

SUMMARYThe motility of the antrum, duodenum and pylorus was recorded with strain gauge transducers and induction coils in conscious beagle dogs. The effect of oleic acid on gastroduodenal motility and on the pyloric diameter was studied in the interdigestive state and during emptying of a mashed potato meal. The flow of digesta was observed fluoroscopically. Gastric emptying was measured by planimetry of the radiopaque gastric silhouette. The intraduodenal injection of oleic acid reduced the diameter of the pylorus in the empty stomach. In the digestive state oleic acid diminished gastric emptying of the potato meal. The antral motility was significantly diminished (amplitudes from 100 + 39 2 to 93 + 41 2 mV, contractile frequency from 43 + 06 to 38 + 15 min-', motility index from 435 + 197 to 345 + 213 V, n = 3400-4700 contractions), whereas the duodenal motility was enhanced (amplitudes from 100 + 49 6 to 106 + 58 6 mV, motility index from 548 + 296 to 567 + 377 V, n = 5800-6400 contractions). The diameter of the pyloric opening during the phase of relaxation was about 25% less in comparison to the control meal. The weaker antral contractions and the less opening of the pylorus diminished gastric evacuation and enhanced retropulsion of the gastric chyme. A higher incidence of segmental duodenal contractions produced a slower transfer of digesta. Results demonstrated that gastric emptying was regulated by several co-operating factors. The pylorus was involved by producing different resistances to flow during its phase of relaxation.

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The aim of the study was to examine gastrointestinal motility after distal gastrectomy and the influence of meal viscosity on gastric emptying. Gastrointestinal motility and gastric emptying of acaloric meals with different viscosities were measured in normal dogs and after a two-thirds gastrectomy with Billroth-I or Roux-Y gastroenterostomy. After distal gastrectomy, gastric emptying depended on the viscosity of the meal, as in normal dogs. Acaloric viscous meals emptied significantly faster in the Billroth-I than in the Roux-Y group due to different contractile patterns of the duodenum and jejunum. In comparison to normal dogs, gastric emptying of viscous meals was accelerated in the Billroth-I and delayed in the Roux-Y group. Several motility parameters of the stomach and intestine differed between the normal and gastrectomized dogs. Thus, after distal gastrectomy, the viscosity of the meal and the contractile patterns of the small intestine are important determinants of gastric emptying.