AJP - Gastrointestinal and Liver Physiology, Vol 255, Issue 2 201-G205, Copyright © 1988 by American Physiological Society
Intestinal anaphylaxis: in vivo and in vitro studies of the rat proximal colon
D. Forbes, M. Patrick, M. Perdue, A. Buret and D. G. Gall
Department of Pediatrics, University of Calgary, Alberta, Canada.
The response of the rat proximal colon to an immunoglobulin E
(IgE)-mediated hypersensitivity reaction was examined. Rats were sensitized
to egg albumin (EA) by intraperitoneal injection, and serum titers of
specific anti-EA IgE were measured at 14 days. Sensitized animals had
titers of greater than or equal to 1:64, whereas no anti-EA IgE antibodies
were detected in controls. Water and electrolyte absorption in the proximal
colon, before and during antigen challenge, was measured by in vivo marker
perfusion. Antigen challenge resulted in significant inhibition of water,
Na+, Cl-, and K+ absorption in vivo. Proximal colonic tissue from
sensitized and control animals was studied in Ussing chambers under
short-circuited conditions. Antigen challenge of sensitized tissue resulted
in significant increases in short-circuit current due to the induction of
active Cl- secretion. No such changes were seen in control tissue. The
abnormalities induced by antigen challenge in tissue from sensitized
animals was blocked by doxantrazole (10(-3) M), a mast cell stabilizer. The
findings indicate that IgE-mediated reactions in rat proximal colon to a
food protein cause pertubations in water and electrolyte transport
secondary to active Cl- secretion and these abnormalities appear to be due
to mast cell degranulation.
