Abstract
We investigated whether the inhibition of nitric oxide (NO) synthesis with N(omega)-nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of NO synthase, affects N-methyl-D-aspartate (NMDA)-induced neurotoxicity in the rat retina in vivo. A single intravitreal injection of NMDA damaged the ganglion cell layer and the inner plexiform layer without affecting the other retinal layers 7 days after injection. Intravitreal injection of (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5, 10-imine hydrogen maleate (MK-801) with NMDA significantly reduced NMDA-induced degeneration of the retina. NMDA-induced degeneration was also prevented by intravitreal injection of L-NAME but not of D-NAME. The protective effect of L-NAME was antagonized by L-arginine. These results suggest that NO plays an important role in NMDA-induced excitotoxic degeneration in the retina.
MeSH terms
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Animals
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Arginine / administration & dosage
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Arginine / toxicity
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Cell Count / drug effects
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Dizocilpine Maleate / administration & dosage
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Dizocilpine Maleate / pharmacology
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Drug Interactions
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Enzyme Inhibitors / administration & dosage
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Enzyme Inhibitors / pharmacology*
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Enzyme Inhibitors / therapeutic use
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Excitatory Amino Acid Agonists / administration & dosage
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Excitatory Amino Acid Agonists / toxicity*
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Excitatory Amino Acid Antagonists / administration & dosage
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Excitatory Amino Acid Antagonists / pharmacology
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Male
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N-Methylaspartate / administration & dosage
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N-Methylaspartate / toxicity*
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NG-Nitroarginine Methyl Ester / administration & dosage
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NG-Nitroarginine Methyl Ester / pharmacology*
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Neurons / cytology
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Neurons / drug effects*
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Neuroprotective Agents / administration & dosage
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Neuroprotective Agents / pharmacology
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Nitric Oxide Synthase / antagonists & inhibitors
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Rats
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Rats, Sprague-Dawley
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Retina / cytology
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Retina / drug effects*
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Retina / pathology
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Stereoisomerism
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Vitreous Body / drug effects
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Vitreous Body / metabolism
Substances
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Enzyme Inhibitors
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Excitatory Amino Acid Agonists
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Excitatory Amino Acid Antagonists
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Neuroprotective Agents
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N-Methylaspartate
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Dizocilpine Maleate
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Arginine
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Nitric Oxide Synthase
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NG-Nitroarginine Methyl Ester