High rate of IgE-mediated histamine release from rat mesenteric mast cells

IgE-dependent histamine release from rat mesenteric mast cells was investigated. Excised mesenterium was cut into pieces and incubated with IgE overnight at 4 degreesC for sensitization. Over 10 pieces of mesenterium specimen could be prepared from a rat. Antigen-induced histamine release from mesenterium specimen was initiated rapidly and reached a plateau in 5 min. In an optimal condition, over 50% of total histamine was released. In contrast, unpurified and purified peritoneal mast cells released only 22.5% and 5.3% of total histamine, respectively, upon IgE stimulation. Tranilast, a mast cell stabilizer, inhibited the histamine release from mesenteric mast cells significantly. The mesenterium might be a useful material for studying tissue-associated mast cell activation.