Alterations of intestinal motor responses to various stimuli after Nippostrongylus brasiliensis infection in rats: role of mast cells.

Nippostrongylus brasiliensis infection induces jejunal mastocytosis associated with enteric nerve remodelling in rats. The aim of this study was to evaluate the intestinal motility responses to meals and to neurotransmitters involved in the control of gut motility (acetylcholine (carbachol), substance P and neurokinin A) in both control and N. brasiliensis-infected rats 30 days post-infection. All rats were equipped with NiCr electrodes in the jejunum to record myoelectrical activity. The duration of disruption of the jejunal migrating myoelectrical complexes (MMC) induced by the different stimuli was determined. Meal ingestion and substance P administration disrupted the MMC pattern for similar durations in the two groups. Carbachol and neurokinin A induced a significantly longer MMC disruption in post-infected rats than in controls (125 +/- 8.3 vs. 70 +/- 6 min for carbachol 100 microg kg-1 and 51 +/- 4 vs. 40 +/- 2 for neurokinin A 50 microg kg-1). The enhanced motor response in postinfected rats was reduced by previous mast cell stabilization with ketotifen or mast cell degranulation with compound BrX 537 A. In conclusion, the increased intestinal motor reactivity to carbachol and neurokinin A in post-N. brasiliensis-infected rats depends upon intestinal mast cell hyperplasia and degranulation.

[Effect of casein on the temporo-spatial organization++ of the contractile activity of the small intestine in the dog]. / Efecto de la caseína en la organización temporo-espacial de la actividad contráctil en el intestino delgado del perro.

Some observations in man and experimental animals have demonstrated that casein decreases intestinal transit speed. However, its effects on intestinal motility have not been studied previously in a systematic fashion. The aim of this work was to study the temporospatial distribution of small bowel motility before and after the administration of calcium caseinate. Studies were performed in fasting dogs using 6 catheters perfused with a pneumo-hydraulic system. After the administration of 300 ml of a 10% solution of calcium caseinate, a global decrease in motor activity was observed, specially of grouped propulsive contractions, they were reduced in 64.9 to 19.5%. On the contrary, a significative increase, in 1.4 to 22%, of individual wave, non propulsive motor activity was observed. These quantitative changes in contractions, specially in their organization and temporo-spatial distribution, may be responsible for the decrease in intestinal transit after the administration of casein.