Intrinsic jejunal propulsion in the guinea pig during parasitism with Trichinella spiralis.

The onset and duration of alterations in intrinsic fluid propelling behavior of guinea pig jejunum caused by infection with Trichinella spiralis was determined using an in vitro monitoring system. Isolated intestinal segments from uninfected hosts produced propulsive complexes of approximately 30-s duration at 125-s intervals. The maximum intraluminal pressure produced at the oral and aboral ends of the segments was approximately 25 cmH2O and the maximum rate of fluid ejection in both the oral and aboral directions was approximately 0.28 ml/s. Segments removed from guinea pigs 10 and 15 days after being inoculated with infective parasite larvae ejected significantly more fluid in the aboral as compared with the oral direction. The maximum aboral pressure developed 10 days postinoculation was 45.7 cmH2O and the maximum aboral fluid ejection rate was 0.60 ml/s. Analogous oral values were 29.0 cmH2O and 0.40 ml/s. This net aboral propulsion was not observed on days 7, 20, 30, or 60 postinoculation. We conclude that precise and highly predictable alterations in intrinsic propulsive behavior of the small intestine are induced by primary infection. These changes are expressed by day 10 postinoculation and are reversed upon spontaneous termination of the intestinal phase of parasitism.