Peritoneal anaphylaxis in the rat after sensitization with mouse antiserum.

Passive peritoneal anaphylaxis in rats, sensitized with mouse antiserum, had characteristics of an IgE-mediated reaction, in that the serum was heat-labile and pretreatment of the rats with disodium cromoglycate (DSCG), or sodium nivimedone, inhibited the release of both histamine and slow-reacting substance of anaphylaxis (SRS-A). Sodium nivimedone was more potent than DSCG as an inhibitor of histamine release. Peak concentrations of histamine and SRS-A in the peritoneal fluids of the rats, were reached within 2 min of antigen challenge and fell to control levels after 20-30 min.