Topical epinephrine and regional ocular blood flow in aphakic eyes of rabbits.
The effects of 4% topical epinephrine bitartrate on regional ocular blood flow were studied in normal, "sham-operated," and aphakic eyes of rabbits. Anterior uveal blood flow decreased in all cases, but reductions in the ciliary processes were less pronounced in aphakic eyes than in sham-operated eyes. Doubling the dose (from 2 to 4 drops) abolished this difference in the ciliary processes, but the increased dose was accompanied by the emergence of a similar (although lesser) effect in the iris. The latter dose additionally decreased retinal blood flow in aphakic eyes compared with the sham-operated eyes. Lens extraction, thus, seems to remove a notable diffusion barrier to topical epinephrine, resulting in both attenuation of its anterior segment effects and in potentiation of a vasoconstrictive response in the posterior pole.
D000818:Animals; D001035:Aphakia / Q000503:physiopathology; D002924:Ciliary Body / Q000098:blood supply; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D005123:Eye / Q000098:blood supply*; D005260:Female; D007908:Lens, Crystalline / Q000601:surgery; D008297:Male; D009883:Ophthalmic Solutions; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D012171:Retinal Vessels / Q000187:drug effects; D014602:Uvea / Q000098:blood supply
D009883:Ophthalmic Solutions; D004837:Epinephrine