Antagonist of platelet-activating factor prevents prostaglandin E2 induced ocular hypertension in rabbits

Topical application of 250 micrograms of platelet activating factor (PAF) or 5 micrograms of prostaglandin E2 (PGE2) to the rabbit's eye is followed by a rise in intraocular pressure (IOP). The occurrence of PAF in the anterior chamber is held responsible for this effect, as appears from the observed concentrations of PAF in a ng/ml-range in the aqueous humor and from the inhibition in the rise of IOP by systemic pretreatment of rabbits with the PAF-antagonist BN 52021 (10 mg/kg). Corneal and conjunctival edema, occurring after application of PAF, are not influenced by BN 52021. Thus, these effects may be ascribed to the non-specific membrane pertubant action of the high local concentration of PAF, necessary to achieve effective concentrations of PAF in the anterior chamber.