Pulmonary Responses to Intravascular Platelet Aggregation in the Cat

Abstract

Abstract Platelet aggregation has been induced in cats by intravenous infusions of ADP, collagen or platelet antiserum, and the airway and pulmonary vascular responses subsequent to such infusions have been studied. Dynamic lung compliance (dyn CL), pulmonary resistance (RL) and the number of circulating platelets were followed together with pulmonary vascular resistance (PVR). Induction of platelet aggregation caused temporary and parallel increases in PVR and in RL and a simultaneous decrease in dyn CL. The major part of these effects was apparently due to active smooth muscle constriction. It could be shown that airway and vascular responses declined and finally disappeared in a characteristic way after repeated episodes of platelet aggregation. The total number of circulating platelets is apparently not the key factor in this connection. The way in which aggregation is induced, as well as the functional state of the circulating platelets, appear to be more important factors. It may be that the platelet release recation is mandatory for the lung responses to intravascular platelet aggregation.