Platelet activating factor, the trigger of haemostatic alterations in rat anaphylaxis

Platelet-activating factor (PAF) generated by an IgE-mediated reaction in the peritoneal cabity of rats was partially purified by adsorption to diatomaceous earth. It aggregated rat platelets and, as a consequence, activated Hageman factor in in vitro, as well as in vivo, conditions. The haemostatic alterations induced by PAF showed similarity to those observed in the early phase of rat anaphylaxis.