Abstract
Intravascular platelet aggregation induced in cats by i.v. infusions of collagen caused a transient increase in pulmonary vascular resistance (PVR) and in non-elastic pulmonary resistance (RL) and a transient decrease in dynamic lung compliance (dyn CL). PVR, dyn CL and platelet aggregation after collagen infusions were unaffected by bilateral cervical vagotomy and atropinization but these procedures reduced the post-infusion rise in RL by about 50%. The administration of indomethacin inhibited platelet aggregation as well as bronchoconstriction after collagen infusion. Intravascular platelet aggregation will apparently cause reflex bronchoconstriction mediated by vagal efferent fibers.