Inhibition by nicotinamide of antigen-induced histamine release from mouse peritoneal mast cells

The in vitro antigen-induced histamine release from mouse peritoneal mast cells actively sensitized with IgE antibodies was inhibited by nicotinamide. The drug was either given in vivo to the sensitized mice (once daily 100 mg/kg) for 7 days before an in vitro experiment or incubated in vitro (in concentrations 1-40 mM) with sensitized mast cells before an antigen challenge. The possible action of nicotinamide on the mechanisms involved in the regulation of antigen-induced histamine release from mast cells is discussed.