Endotoxin interaction with canine platelets fails to stimulate thromboxane production

Endotoxin induced a limited, dose-dependent change in light transmission when incubated with canine platelet-rich plasma. This response differed from that induced by collagen and ADP in its magnitude and by its insensitivity to a wide variety of inhibitors. However, endotoxin did not induce detectable aggregation of canine platelets in citrated whole blood under conditions where collagen and ADP were effective. In addition, thromboxane production was not stimulated. These data are consistent with the occurrence of an immune adherence reaction between endotoxin and canine platelets, as has been previously described for other species, but without platelet activation (aggregation, mediator, and thromboxane release).