HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Osborne, N. N. Articles by Wood, J. P. M. Search for Related Content PubMed PubMed Citation Articles by Osborne, N. N. Articles by Wood, J. P. M.

Metipranolol Blunts Nitric Oxide-Induced Lipid Peroxidation and Death of Retinal Photoreceptors: A Comparison with Other Anti-Glaucoma Drugs

From the Nuffield Laboratory of Ophthalmology, Oxford University, Oxford, United Kingdom.

PURPOSE. To determine the effect of the nitric oxide donor sodium nitroprusside (SNP) on rat retinas and to see whether detrimental changes could be attenuated by known antiglaucoma drugs.

METHODS. SNP was injected into the rat eye and retinas were analyzed by the terminal-deoxynucleotidyl transferase dUTP-linked nick end labeling (TUNEL) procedure and by immunohistochemistry. In some instances, retinal homogenates were analyzed by immunoblot for proteins associated with either photoreceptors or with cell death. Analysis of lipid peroxidation in retinal homogenates was by the thiobarbituric acid reactive species (TBARS) formation method.

RESULTS. SNP caused an increase in the number of retinal photoreceptors labeled for DNA breakdown by the TUNEL procedure and for caspase-3 and Bcl-2. After intravitreal injection of SNP, breakdown of poly(ADP-ribose) polymerase and an increase in the level of active forms of caspase-3 and Bcl-2 were detected. Furthermore, photoreceptor-specific rhodopsin kinase was reduced. SNP also stimulated formation of TBARS in retinal homogenates, occurring to a greater extent in retinas from young Royal College of Surgeons rats lacking photoreceptor degeneration. This supports the view that the photoreceptors are the prime target for SNP. Significantly, of several antiglaucoma drugs tested only metipranolol and its active metabolite, desacetylmetipranolol, blunted the SNP-induced retinal changes.

CONCLUSIONS. Of all antiglaucoma drugs tested, only metipranolol was able to attenuate SNP-induced lipid peroxidation and activation of apoptosis in photoreceptors. Because oxidative injury has been implicated in the pathogenesis of certain ocular diseases, these findings could prove to be of clinical significance.

This article has been cited by other articles:

				H. She, T. Nakazawa, A. Matsubara, T. Hisatomi, T. A. Young, N. Michaud, E. Connolly, A. Hafezi-Moghadam, E. S. Gragoudas, and J. W. Miller Reduced Photoreceptor Damage after Photodynamic Therapy through Blockade of Nitric Oxide Synthase in a Model of Choroidal Neovascularization Invest. Ophthalmol. Vis. Sci., May 1, 2007; 48(5): 2268 - 2277. [Abstract] [Full Text] [PDF]

				N. N. Osborne and J. P. M. Wood The {beta}-Adrenergic Receptor Antagonist Metipranolol Blunts Zinc-Induced Photoreceptor and RPE Apoptosis. Invest. Ophthalmol. Vis. Sci., July 1, 2006; 47(7): 3178 - 3186. [Abstract] [Full Text] [PDF]