Histamine release in acute anaphylactic enteropathy of the rat.

Investigations into the role of allergic enteropathy in acute and chronic intestinal inflammation have been hampered by the lack of objective confirmation for intestinal mast cell activation. Utilizing an established model of acute allergic enteropathy in the rat, we report the enhanced intraluminal recovery of the mast cell mediator histamine after in vivo antigen challenge in sensitized animals. The enhanced histamine recovery is dose dependent, antigen-specific, and restricted to that segment of bowel challenged, thus confirming local intestinal anaphylaxis. The progression of histologic enteropathy is documented and shown to correlate with the entry of mast cells into the intestinal lumen during, but not before, the anaphylactic response. Pretreatment of the sensitized animal with prostaglandin E2 or doxantrazole, but not cromolyn, significantly inhibits the anaphylactic response.