Gómez E

Effect of casein and casein hydrolysate on small bowel motility and D-xylose absorption in dogs.

Abstract Food administration is followed by the appearance of a small intestinal pattern of irregular contractions. Studies on the relationship between intestinal motor activity, transit and absorption have yielded contradictory results. Since previous studies have shown that casein and casein hydrolysate led to a decrease of small intestinal motor activity and transit, the aim was to evaluate the effect of these nutrients on small intestinal motility and D‐Xylose absorption. Studies were performed in five dogs with a duodenal fistula; motility was recorded by means of six infused catheters and external transducers. Three test solutions with the same osmolality, lactulose, casein and casein hydrolysate, were continuously infused through the duodenal cannula. D‐Xylose was injected in the duodenum and plasma levels determined at regular intervals. Absorption of D‐Xylose was greatest during the administration of casein hydrolysate, the lowest levels were seen with lactulose and intermediate levels were obtained with casein. The effect of casein hydrolysate on small intestinal motility was characterized by a decrease in the frequency of contractions. Propulsive contractions were decreased after the infusion of both casein and casein hydrolysate. Lactulose infusion was followed by the greatest motor activity of both frequency and propulsive contractions. These results suggest that the motor patterns observed with casein and casein hydrolysate lead to increased intestinal absorption of D‐Xylose.

Relationship between antropyloric and intestinal motility and duodenogastric reflux in fasting dogs

Duodenogastric reflux was studied in fasting dogs with gastric and duodenal cannulae, by means of recovery from the gastric cannula of phenol red infused into the duodenum and bile acids recovered from the gastric cannula. Simultaneously, antropyloric and intestinal motility was studied in order to establish a relationship between motility and duodenogastric reflux. A different pattern of duodenogastric reflux was observed, depending on the method utilized. While a significantly higher reflux was observed during phase II in bile acid studies, an irregular pattern not related to the different phases of the interdigestive motor complex was observed in experiments with phenol red. Antral motility estimated by an antral motility index showed a statistically significant correlation with DGR estimated by both methods. Pyloric pressure and intestinal motility did not show a correlation with DGR. We concluded that the results obtained in studying duodenogastric reflux depend on the method used. The main factor related to increased duodenogastric reflux was the decreased antral motility.

Continuous Recording of Pyloric Sphincter Pressure in Dogs Relationship to Migratory Motor Complex

Antral, pyloric, and small bowel intraluminal pressures were continuously recorded in dogs with gastric and duodenal cannulae. A cyclic phasic activity related to fasting motility in the antrum and small bowel was observed at the level of the pylorus. During phase I of the interdigestive motility complex, manometry was characterized by pressure variations of 31±2 cm H2O. During phase II, two type of waves were observed: small waves similar to those seen during phase I, with superimposed waves of higher amplitude (89±1.9 cm H2O). Pyloric pressure during phase III, showed a predominance of waves of even greater amplitude: 103±3.9 cm H2O. A basal tone of 65.6±3.2 cm H2O above the duodenal pressure was recorded throughout the period of study; but during phase III, frequent decreases in basal pressure were also observed. This relaxation of the pylorus during phase III of the IDMC may be related to the mechanism for size discrimination of particles leaving the stomach at the gastroduodenal junction.

Divergent effect of saline and glucose solutions on myoelectric and motor activity of canine small bowel

Previous work has shown that stimulation of osmotic receptors in the duodenal mucosa is followed by an increase in small intestinal motility. This effect was consistently observed with saline solutions, while stimulation or inhibition is observed when glucose is the solute. To gain further insight into the mechanisms of these apparent contradictory effects, we have perfused the intestine with saline and glucose solutions while simultaneously recording small bowel electrical and motor activity. Also to elucidate the influence of the spontaneous fasting activity, infusions were done on two different phases of the migrating motor complex infusion of 10 ml of both NaCl and glucose (1250 and 2500 mOsm/kg) in Phase I of the migrating motor complex, elicited the appearance of spike potentials and contractions. When infused during Phase II, NaCl caused an increase in the frequency of the irregular motor activity characteristics of this phase, due to a greater coupling of electrical and motor events. Also a greater amplitude of contractions was seen. In contrast, glucose infusion in Phase II was associated with a decrease of both electrical events and contractions. We conclude that the effect of hyperosmolar solutions is influenced by the solute and the phase of the migrating motor complex in which they are infused.

Relationship between small intestinal fasting motility and vomiting in dogs

Preceding vomiting, several changes in small intestinal motility have been described. They consist mainly of high-amplitude retrograde contractions and inhibition of motility before and after these contractions. The recordings of 94 episodes of emesis occurring spontaneously, during manometric studies of intestinal motility by means of infused catheters in dogs with gastric and duodenal cannulae, showed that 95.7% of all episodes developed during phase II of the migratory motor complex. In order to establish whether different phases of the fasting cyclic activity are associated with a different sensitivity to emetic stimulus, two agents, apomorphine, a centrally acting drug and copper sulfate, a peripherally acting agent, were administered at the beginning of phases I and II of the migratory motor complex. Coincident with spontaneously occurring vomiting, a statistically significative greater number of responses to both emetic agents was observed during phase II as compared to phase I. This finding suggests that cyclic changes of the small bowel motility are related to changes in the threshold of the vomiting center.