Anaphylactic colonic hypersecretion in cow's milk sensitized guinea‐pigs depends upon release of Interleukin‐1, prostaglandins and mast cell degranulation

SUMMARY Methods: The effect of β‐lactoglobulin (β‐LGI) challenge on net water movements into the proximal colon and the role of Interleukin‐1 (IL‐1), prostaglandins and mast cell degranulation on the challenge‐induced net water changes were assessed in vivo using isolated colonic loops in anaesthetized guinea‐pigs immunized to bovine milk. Results: β‐lactoglobulin challenge infused into the colonic loop during 30 min reversed the net water flux into a net secretion during the period of antigen infusion. Doxantrazole, a mast cell stabilizing agent, administered 120 min before challenge infusion, suppressed challenge‐induced hypersecretion. Similarly recombinant IL‐1 receptor antagonist protein abolished the antigen‐induced colonic secretory effect. Indomethacin, a prostaglandin synthesis inhibitor, administered 20 min prior to antigen infusion, significantly (P < 0.05) reduced, but did not abolish, the challenge‐induced colonic secretory effect. Conclusions: These results suggest that IL‐1 plays an important role in antigen challenge‐induced colonic hypersecretion which involves mast cell degranulation and prostaglandin release.