Long-term influence of enteric infection on jejunal propulsion in guinea pigs.

The intrinsic fluid-propelling behavior of guinea pig jejunal segments was reportedly altered by primary infection with Trichinella spiralis from day 10 to day 20 postinoculation. After that time propulsive behavior returned to normal. The objective in the investigation reported here was to determine if jejunal responsiveness to an infection is influenced by prior exposure to the parasite. Accordingly, jejunal propulsion was examined in guinea pigs reinfected 2 mo after the initial inoculation with the parasite. Propulsive behavior was measured in vitro by attaching oral and aboral ends of jejunal segments to a propulsion evaluation system that imposed input-output conditions of constant capacitance and negligible resistance. Propulsive complexes produced by segments removed from animals 60 days after primary inoculation were generally similar in configuration to those produced by segments from uninfected hosts. The pronounced net aboral propulsive behavior previously observed 10-20 days after primary infection was not observed in segments from animals 60 days postinfection or from uninfected controls. After secondary inoculation the fluid volume expelled per propulsive complex began to increase within 1 day and net aboral propulsive behavior was clearly evident 2 days postinoculation. As net aboral propulsive behavior was induced approximately five times faster after secondary as compared with primary inoculation with T. spiralis, it is evident that the overall intrinsic mechanisms that are responsible for an earlier onset of net aboral propulsive behavior are responsive for at least 2 mo after initial exposure to the parasite.