Inhalation of platelet-activating factor increases respiratory resistance in rats: determination by means of an astograph under nonanesthetized conditions

Intratracheal administration of platelet-activating factor (PAF) to dogs, baboons, and humans has been shown to induce hyperreactivity of the airways and contraction of the smooth muscle. However, it has not yet been reported whether intratracheal administration of PAF to rats induces hyperreactivity. In the present study, the authors estimated the respiratory resistance of rats during intratracheal administration of PAF in order to evaluate the reactivity of the airways to PAF. In both the nonsensitized group and the sensitized group of rats, intratracheal administration of PAF induced an increase in respiratory resistance. The results obtained clarify that responsiveness to PAF exists in the airways of rats.