Computer analysis of intestinal motility: effects of cholecystokinin and neurotensin on jejunal contraction patterns

The motility of the intestine consists of various contractile patterns which have either segmenting or propulsive function. To differentiate and quantify intestinal contractile patterns the temporal and spatial relation of several closely spaced transducers have to be analysed. For this purpose a special computer method was developed. The system consists of a subsystem for data acquisition and on-line peak detection and a personal computer for data storage and off-line analysis. The subsystem identifies each contraction on the basis of preestablished threshold and timing criteria. Economical and appropriate processing of signals from multichannel recordings requires data reduction which is performed by storing only the voltage and time characteristics of the contraction minimum and maximum. Subsequent analysis of the stored data, especially the measurement of the length of spread of contractions yields a more detailed analysis than commonly obtained. This method enables a rapid detection and exact numerical analysis of signals independent of their wave shapes. Intravenous infusion of neurotensin after administration of a non-caloric cellulose meal decreased the length of spread of contraction waves and slowed the transit rate of luminal contents. Cholecystokinin had a powerful stimulating effect by increasing the length of spread of contraction waves and by accelerating the transit rate.     

Gastric emptying after roux-y and billroth-I gastrectomy depends on viscosity of meal and contractile patterns of small intestine in dogs

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.Studies were supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/3-1.     

Effects of somatostatin on luminal transit and absorption of nutrients in the proximal gut of minipigs

A discrepancy exists on the effects of somatostatin on the absorption of nutrients: in humans, absorption was found to be reduced, whereas in rats no effects were observed. However, intestinal absorption might be influenced by the transit rate of contents. This was not considered in previous studies. Therefore, we investigated simultaneously the effects of somatostatin on the absorption of nutrients and on luminal transit. In five minipigs (44–62 kg), a 150-cm segment of the proximal jejunum was temporarily isolated by two cannulas and perfused with an oligomer diet (60% carbohydrate, 18% protein, and 22% fat). The perfusion rate was 2 kcal/min. Flow rate and mean transit time were determined by markers (Cr-EDTA and Cu-EDTA). Somatostatin was infused intravenously at rates of 0.5, 1.25, 2.5, and 5µg/kg/hr. In control experiments saline was administered intravenously. Somatostatin dose-dependently diminished flow rate of luminal contents and increased the transit time. At the largest dose of somatostatin (5µg/kg/hr) flow rate was reduced by 50% compared with control infusion of saline (1.0±0.4 vs 2.0±0.05 ml/min,P<0.05), and transit time was increased 3.6-fold (39.8±4.7 vs 11.2±4.9 min;P<0.05). Somatostatin also dose-dependently enhanced the absorption of nutrients and energy. However, the increase in absorption was small compared with the effects on flow rate and transit time. At the largest dose (5µg/kg/hr) absorption of energy, carbohydrate, protein, and fat was enhanced only by 9.7%, 7.0%, 5.2%, and 15.3%, respectively (49.9 vs 40.2%, 50.9 vs 43.9%, 67.3 vs 62.1%, and 30.1 vs 14.8% during saline infusion;P<0.05). Results indicate that the major effects of somatostatin consist in a marked reduction of flow rate and a delay of luminal transit. The small increase in absorption was caused by the delay in transit and the prolonged contact of the nutrients with the mucosa. Therefore, in absorption studies, effects on transit need to be considered.     

Effects of nutrients on gastrointestinal motility and gastric emptying after distal gastrectomy with Roux-Y gastrojejunostomy in dogs

The aim of the study was to clarify whether nutrients are still capable of slowing gastric emptying following Roux-Y gastrectomy, as in normal dogs. Gastrointestinal motility and gastric emptying of acaloric and nutritive meals with different viscosities were measured in normal dogs and after a two-thirds Roux-Y gastrectomy. In gastrectomized dogs low-viscosity nutritive meals emptied unduly rapidly in an initial phase, although the frequency and spread of contractions, ie, the propulsive activity of the jejunal Roux limb were diminished. A slow emptying rate during the following period was due to a long-lasting inhibition of gastric and jejunal motility. Medium-viscosity nutritive meals emptied in gastrectomized dogs as slowly as in normal animals, but this effect was primarily caused by the meal viscosity and only secondarily by the nutrients. It is concluded that following Roux-Y gastrectomy a regulation of gastric emptying is preserved; however, the onset of an effective control is delayed, resulting in a rapid initial emptying of low-viscosity meals.Studies were supported by the Deutsche Forschungsgemeinschaft grant Eh 64/3-1.