Intestinal myoelectric response in two different models of acute enteric inflammation

The inflammatory responses to intraluminal administration of the cytotoxic lectin ricin or the hapten 2,4,6-trinitrobenzenesulfonic acid in 25% ethanol were compared. Myoelectric activity was recorded from in vivo ileal loops in rabbits after administration of either agent. At the end of a 6-h study the loops were removed and prepared for histological evaluation and for ex vivo generation of leukotriene (LT) C4 and prostaglandin (PG) E2. Both agents induced significant increases in mucosal damage, polymorphonuclear leukocyte infiltration, and edema. These changes tended to be patchy in the hapten model and confluent in the ricin model. Spike burst activity and mucosal LTC4 and PGE2 generation were also enhanced significantly. Intraluminal administration of the specific LTD4 antagonist Wy-48252 1 h before either inflammagen, significantly inhibited the myoelectric response without affecting tissue morphology or eicosanoid synthesis. These data demonstrate that there is a stereotypic spike burst response to acute inflammation, which is mediated in part by LTD4.