title: Oxygen free radicals adversely affect the regulation of vascular tone by nitric oxide in the rabbit retina under high intraocular pressure.
abstract: Flash electroretinograms (ERG) were recorded in the rabbit eye submitted to high intraocular pressure (HIOP) induced by the suction-cup method. When intraocular pressure rose to 100 mmHg, ERG was suppressed but rapidly recovered even under HIOP when animals were pre-treated either intravitreously with a nitric oxide donor, sodium nitroprusside, or intravenously with free radical scavengers, superoxide dismutase (SOD)+catalase. In contrast, injection of a nitric oxide synthesis inhibitor, nitro-L-arginine, into the vitreous cavity inhibited the protective effect of SOD+catalase during HIOP-induced ERG extinction. These results suggest that nitric oxide could play a role in the regulation of ocular vessel tone and that severe ischemia can impede this effect through oxygen-derived free radical generation.
authors.affiliation: Laboratory of Cellular Physiology, University of Montpellier, France.
authors.forename: S
authors.initials: S
authors.lastname: Veriac
authors.forename: G
authors.initials: G
authors.lastname: Tissie
authors.forename: C
authors.initials: C
authors.lastname: Bonne
mesh_terms: D000818:Animals; D004596:Electroretinography / Q000187:drug effects; D005609:Free Radicals; D009569:Nitric Oxide / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D009798:Ocular Hypertension / Q000503:physiopathology*; D011817:Rabbits; D012171:Retinal Vessels / Q000503:physiopathology*; D013482:Superoxide Dismutase / Q000494:pharmacology; D014655:Vascular Resistance / Q000502:physiology*
chemical_list: D005609:Free Radicals; D009599:Nitroprusside; D009569:Nitric Oxide; D013482:Superoxide Dismutase