A method for measuring changes in tracheal mucus gel layer thickness as an indication of an immediate hypersensitivity response.

A visual method for measuring increase in tracheal mucus gel layer thickness as an indication of an immediate hypersensitivity response, using a Zeiss slitlamp and pachymeter is described. Mucus gel layer thickening is antigen dose dependent. Antigen challenge of nonsensitized rats does not cause significant increases in gel thickness dispelling the notion that changes in the gel layer result from nonspecific irritation. Cromolyn sodium, cimetidine, and FPL-55712 inhibit increases in gel layer thickness following antigen challenge of actively sensitized rats, while atropine, pyrilamine, and methysergide do not.