Effects of a nitric oxide synthase inhibitor on prostaglandin-induced aqueous flare elevation in pigmented rabbits

To evaluate the possible role of nitric oxide in the pathogenesis of exogenous prostaglandin (PG) induced aqueous flare elevation, we examined the effect of NG-nitro-L-arginine methyl ester (L-NAME), an L-arginine analogue acting as a specific inhibitor of nitric oxide synthase, on the elevation of aqueous flare in pigmented rabbits. L-NAME was injected into the ear vein of the animals. PGE1, PGE2, and PGF2 alpha were administered topically to the cornea using a glass cylinder. Aqueous flare was measured using a laser flare cell meter. PGE1, PGE2, and PGF2 alpha increased the aqueous flare dose dependently (5-100 micrograms/ml). L-NAME inhibited PGE1-, PGE2-, or PGF2 alpha-induced aqueous flare elevation. L-NAME, injected 30-90 min before PG application, inhibited the aqueous flare elevation maximally. We believe that nitric oxide may be involved in the pathogenesis of PG-induced aqueous flare elevation in rabbits.