PLATELET ACCUMULATION INDUCED BY BACTERIAL-ENDOTOXIN IN RATS

We studied the effects of i.v. administration of endotoxin (Escherichi a coli, Serotype 0127:B8) on the kinetics of In-111-labelled platelets within the pulmonary, abdominal and splenic vascular beds of the rat, and on the radioactivity present in dissected samples of splenic and hepatic tissues. Bolus i.v. injection of endotoxin to anaesthetised ra ts caused a dose-dependent, transient accumulation of In-111-labelled platelets in the pulmonary vasculature Increased radioactivity, sugges tive of platelet sequestration, was detected in tissue samples from bo th the spleen and the liver at 4 5 h compared to the radioactivity det ected in those organs in vehicle treated rats. The modulation of endot oxin-induced platelet accumulation within the lungs, spleen and liver by pharmacological agents was investigated. The pulmonary, hepatic and splenic platelet accumulation induced by endotoxin was unaffected by pre-treatment of the animals with indomethacin, Hirulog(TM) or L-NAME. Pre-treatment with dexamethasone significantly reduced the platelet a ccumulation within the liver and spleen, but not the lungs.