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

Nippostrongylus brasiliensis infection induces jejunal mastocytosis associa ted with enteric nerve remodelling in rats. The aim of this study was to ev aluate the intestinal motility responses to meals and to neurotransmitters involved in the control of gut motility (acetylcholine (carbachol), substan ce 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 je junum to record myoelectrical activity. The duration of disruption of the j ejunal migrating myoelectrical complexes (MMC) induced by the different sti muli was determined. Meal ingestion and substance P administration disrupte d the MMC pattern for similar durations in the two groups. Carbachol and ne urokinin A induced a significantly longer MMC disruption in post-infected r ats than in controls (125 +/- 8.3 vs. 70 +/- 6 min for carbachol 100 mu g k g(-1) and 51 +/- 4 vs. 40 +/- 2 for neurokinin A 50 mu g kg(-1)). The enhan ced motor response in postinfected rats was reduced by previous mast cell s tabilization with ketotifen or mast cell degranulation with compound BrX 53 7 A. In conclusion, the increased intestinal motor reactivity to carbachol and neurokinin A in post-N. brasiliensis-infected rats depends upon intesti nal mast cell hyperplasia and degranulation.