PAF

48740 RP (RP-55778) is a platelet-activating factor (PAF) antagonist. In animals treated with 48740 RP only, the number of platelets is increased at a time corresponding to 2 and 4 h after the exposure to lipopolysaccharide (LPS) and the number of eosinophils is also slightly increased. Treatment with 48740 RP in combination with the LPS exposure does not influence the increase in neutrophils seen 2 and 4 h after exposure. At 24 h the increase in the number of neutrophils is about half that in control animals. No effects are found on the LPS-induced increase in number of platelets. In animals pretreated with 48740 RP, there is a significant reduction in capillary permeability.