Characterization of the activity of a platelet activating factor antagonist, CV-3988.

CV-3988 inhibited the vascular permeability increase induced by C16-PAF and C18-PAF in rat skin in a dose-dependent manner. The inhibition was shown to be specific and competitive with PAF on its receptor by the following observations: parallel shift of the dose-response curve; crossing of double reciprocal plots on the intersection of the ordinate; and no inhibition on other autacoids such as bradykinin, histamine, 5-hydroxytryptamine and LTC4. PAF-induced blood pressure fall in rats was also suppressed by pretreatment with CV-3988 selectively.