Ethylenediamine tetraacetic acid and histamine release from rat mast cells

The action of ethylenediamine tetraacetic acid (EDTA) on the release of histamine induced by clinical dextran, concanavalin A and compound 48/80 has been studied in rats after intraperitoneal and intrapedial injection as well as in tubes containing isolated peritoneal mast cells. Whereas large doses of EDTA were required for inhibiting histamine release in the whole animal, relatively much smaller concentrations were necessary when the inhibitor was injected locally into the paw or included in the incubation mixture with isolated cells. When dextran was used as the histamine releaser, EDTA was relatively much more effective an inhibitor in vitro than in vivo.