Histamine and the mast cell degranulator, compound 48/80 produced elevations in short-circuit current, an electrical measure of active anion secretion, across porcine ileal mucosa sheets mounted in Ussing chambers. Luminally-applied β-lactoglobulin produced similar effects in mucosal sheets from cow's milk-sensitized pigs. Their secretory effects were attenuated by blockers of H1-histamine receptors, neuronal conduction or epithelial Na+/K+/Cl- cotransport. The δ-opioid agonist [D-Pen2,D-Pen5]enkephalin suppressed mucosal responses to these substances in a naltrindole-reversible manner. Furthermore, submucosal mast cells and δ-opioid receptor-immunoreactive nerve fibers were observed in close juxtaposition. Intestinal neural pathways linking immediate hypersensitivity to secretory host defense appear to express inhibitory δ-opioid receptors. (C) 2001 Elsevier Science B.V.
Bibliographical noteFunding Information:
The authors thank Drs. Mary Pampusch (Department of Animal Science, University of Minnesota), Anjali Kulkarni-Narla and Dennis Foss (Department of Veterinary PathoBiology, University of Minnesota) for excellent technical assistance or advice during this study. We are also grateful for gifts of nor-BNI and anti-δ-opioid receptor antiserum from Drs. Philip Portoghese (Department of Medicinal Chemistry, University of Minnesota) and Robert P. Elde (Department of Neuroscience, University of Minnesota), respectively. This study was funded by NIH grant DA-10200. S.P. was supported by a Royal Thai Government fellowship.
- Food allergy