[Bronchial hyperresponsiveness to histamine in guinea pig induced by intravenous administration of platelet activating factor].

Platelet activating factor (PAF) has recently been demonstrated to play an important role in allergic diseases such as bronchial asthma. Changes in airway wall thickness have recently been suggested to cause excess airway narrowing of asthma. In this study, the authors examined the bronchial hyperresponsiveness to histamine in guinea pig induced by intravenous administration of PAF by measuring dynamic compliance and dynamic respiratory resistance. Moreover, a new formula which can exclude the effect of the changes of the airway wall thickness was proposed. With this formula, the administration of PAF was suggested to induce airway wall to be thickened. The ratio of bronchial smooth muscle constriction by histamine was significantly enhanced by the administration of PAF (p less than 0.05). Moreover, antagonists such as CV3988 and CV6209 inhibited the effect of PAF. The above results suggest that PAF may be an important mediator affecting bronchial hyperresponsiveness.