Effects of adenosine-5'-triphosphate (ATP) on rat mast cells: influence on anaphylactic and compound 48/80-induced histamine release.

Anaphylactic histamine release from mast cells isolated from actively sensitized rats was inhibited by pre-incubation with micromolar concentrations of ATP. The inhibition was reversible under various experimental conditions and was counteracted by the presence of calcium in the incubation medium. Histamine release induced by compound 48/80 was similarly affected. Mast cells exposed to antigen under conditions when histamine release was inhibited by ATP became desensitized. The results indicate that ATP inhibits the release mechanism at a step which occurs after the binding of antigen to IgE.