[The participation of platelets in anaphylactic shock in the rat].

In the IgE-sensitized Brown Norway rats, the intravenous antigen challenge resulted in systemic anaphylactic shock without thrombocytopenia. In the IgG-sensitized Wistar rats, thrombocytopenia occurred during the anaphylactic shock. It is linked with circulating immun-complexes. Treatment of IgG-sensitized Wistar rats by antiplatelet serum, by promethazine (anti-H1), cyproheptadine (anti-5-HT1) or phenidone, a cyclo-oxygenase and lipoxygenase inhibitor, did not protect against the anaphylactic shock. In the rat, platelets did not play a significant rôle in the pathogenesis of the various forms of the anaphylactic shock.