AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 2 266-G273, Copyright © 1986 by American Physiological Society
Anamnestic stimulus-specific myoelectric responses associated with intestinal immunity in the rat
J. M. Palmer and G. A. Castro
Changes in small intestinal motility reflective of local anaphylaxis are
hypothesized to be associated with the rapid, immune-mediated rejection of
infective larvae of the nematode Trichinella spiralis. This hypothesis was
tested by comparing intestinal myoelectric activity in primarily and
secondarily infected rats; the latter group represented immunized hosts,
i.e., immunized by initial contact with the parasite. Patterns of slow
waves, action potentials, interdigestive migrating myoelectric complexes,
and migrating action-potential complexes induced by secondary infection
differed from those associated with primary infection. Patterns in both
cases differed from those in uninfected rats. Secondary but not primary
infection evoked changes in myoelectric patterns within 15 min after
administration of infective larvae. These changes could not be elicited by
inoculation with dead larvae, larval excretory-secretory antigens, or a
heterologous parasite, Eimeria nieschulzi. Results indicate that altered
smooth muscle contractile activity is part of an anamnestic,
stimulus-specific response to T. spiralis in immunized rats. These changes
may represent the in vivo equivalent of the anaphylactically mediated
intestinal smooth muscle contraction elicited in vitro in the Schultz-Dale
reaction.
