Mediators of anaphylaxis-induced ion transport changes in small intestine.
Net ion transport by jejunum of rats immunized against Trichinella spiralis on challenge with parasite-derived antigen was measured in Ussing chambers as a rapidly expressed, biphasic rise and fall (phase I and II) in short-circuit current (delta Isc). This delta Isc is triggered by mucosal anaphylaxis. Our objective is to identify mast cell-derived substances that mediate the epithelial response. Antigenic challenge of sensitized jejunum caused the release of 5-hydroxytryptamine (5-HT), histamine, and prostaglandin E2 (PGE2). The antigen-induced phase I response was mimicked by exogenous 5-HT or histamine and blocked by pretreatment of tissue with 5-HT and histamine H1-antagonists; the phase II response was mimicked by exogenous PGE2 and blocked by an inhibitor of prostaglandin synthesis. Atropine and tetrodotoxin significantly blunted the phase I response as well as the delta Isc caused by exogenous 5-HT or histamine while only slightly reducing the phase II response and not affecting the delta Isc induced by PGE2. Results support the conclusion that 5-HT, histamine, and PGE2 mediate the antigen-induced change in Isc through direct and neurally mediated stimulation of jejunal epithelium.
D000707:Anaphylaxis / Q000378:metabolism*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001692:Biological Transport; D002712:Chlorides / Q000378:metabolism; D015232:Dinoprostone; D004848:Epithelium / Q000378:metabolism; D006636:Histamine Release; D006967:Hypersensitivity / Q000378:metabolism; D007114:Immunization; D007421:Intestine, Small / Q000378:metabolism* / Q000469:parasitology; D007477:Ions / Q000378:metabolism*; D007583:Jejunum / Q000378:metabolism / Q000469:parasitology; D008297:Male; D008407:Mast Cells / Q000378:metabolism; D011458:Prostaglandins E / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D014234:Trichinella / Q000276:immunology
D002712:Chlorides; D007477:Ions; D011458:Prostaglandins E; D012701:Serotonin; D013779:Tetrodotoxin; D001285:Atropine; D015232:Dinoprostone