Effect of BN 52021, a specific PAF-acether antagonist, on cardiac anaphylaxis in Langendorff hearts isolated from passively sensitized guinea-pigs.

Hartley guinea-pigs were sensitized passively with antiovalbumin rabbit serum. Their isolated perfused hearts responded to the specific antigen with a marked decrease in contractile force, increase in perfusion pressure, and rhythm disturbances. All these impairments except tachycardia were decreased by BN 52021, a specific PAF-acether receptor antagonist, applied in a constant infusion before ovalbumin challenge. These findings suggest that PAF-acether plays a major role as mediator in cardiac anaphylaxis, and BN 52021 may be a valuable therapeutic agent in allergic conditions.