Protection against light-induced retinal degeneration by an inhibitor of NO synthase

Neuroreport. 1993 Dec 13;5(3):233-6. doi: 10.1097/00001756-199312000-00012.


The existence of nitric oxide synthase (NOS) in retinal rod outer segments and pigmented epithelial cells suggests that NO in excess could impair the interaction between these cells, resulting in photoreceptor degeneration. To test this hypothesis, NG-nitro-L-arginine methyl ester (L-NAME), an NOS inhibitor, was intraperitoneally injected daily into rats subjected to constant illumination for 7 days in order to destroy their photoreceptors. By measuring photoreceptor nuclear layer thicknesses, we found that L-NAME partially protects (by up to 35%) against the degeneration of photoreceptors and acts to maintain their organization. Thus NO may be involved in the process by which photoreceptor degeneration results from constant illumination of the retina.

MeSH terms

  • Amino Acid Oxidoreductases / antagonists & inhibitors*
  • Animals
  • Arginine / administration & dosage
  • Arginine / analogs & derivatives*
  • Arginine / therapeutic use
  • Injections, Intraperitoneal
  • Light / adverse effects*
  • Male
  • NG-Nitroarginine Methyl Ester
  • Nitric Oxide Synthase
  • Photoreceptor Cells / drug effects
  • Photoreceptor Cells / radiation effects
  • Rats
  • Retinal Degeneration / prevention & control*


  • Arginine
  • Nitric Oxide Synthase
  • Amino Acid Oxidoreductases
  • NG-Nitroarginine Methyl Ester