Intestinal anaphylaxis: rapid changes in mucosal ion transport and morphology.

Anaphylactic reactions can be elicited by beta-lactoglobulin (beta LG) in the isolated colonic and ileal mucosae of guinea pigs fed cow milk. We have shown that these tissues respond to antigen challenge with a rapid rise in short-circuit current (SCC) due to net chloride secretion in the colon and less well-characterized ion movements in the ileum. Here, tissues were characterized morphologically at or near the peak of the SCC response 2 min after antigen addition. These sensitized preparations, or naive tissues passively sensitized with immune sera and challenged with beta LG, showed numerous structural alterations that correlated significantly with the change in SCC. In the ileum, these changes included compound exocytosis of mucous granules from goblet cells of crypts but not of villi and a decrease in the intercellular space of the crypts. In contrast, colonic goblet cells of both crypts and luminal surface showed no evidence of secretion, but crypt architecture was reproducibly and characteristically altered. Thus antigen challenge of intestinal mucosa results in temporally related but diverse changes in morphology and ion transport.