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Analysis of the Neuroprotective Effects of Various Nitric Oxide Donor Compounds in Murine Mixed Cortical Cell Culture
Author(s) -
Vidwans Aniruddha S.,
Kim Sungmee,
Coffin Deborah O.,
Wink David A.,
Hewett Sandra J.
Publication year - 1999
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1999.0721843.x
Subject(s) - neuroprotection , nitric oxide , chemistry , nmda receptor , neurotoxicity , glutamate receptor , biochemistry , glutathione , biophysics , superoxide dismutase , pharmacology , antioxidant , receptor , biology , toxicity , organic chemistry , enzyme
Nitric oxide (NO) has been implicated in both the pathogenesis of and protection from NMDA receptor‐mediated neuronal injury. This apparent paradox has been attributed to alternate redox states of nitrogen monoxide, whereby, depending on the redox milieu, nitrogen monoxide can be neuroprotective via nitrosation chemistry or react with superoxide to form secondary toxic species. In our murine mixed cortical cell culture system, the NONOate‐type NO donors diethylamine/NO complex sodium (Dea/NO), ( Z )‐[ N ‐(3‐ammoniopropyl)‐ N ‐( n ‐propyl)amino]diazen‐1‐ium‐1,2‐diolate (Papa/NO), and spermine/NO complex sodium (Sper/NO), as well as the S ‐nitrosothiols S ‐nitroso‐L‐glutathione (GSNO) and S ‐nitroso‐ N ‐acetyl‐D,L‐penicillamine (SNAP) (NO + equivalents), decreased NMDA‐induced neuronal injury in a concentration‐dependent manner. 8‐Bromo‐cyclic GMP did not mimic the inhibitory effects of the donors, suggesting that the neuroprotection was not the result of NO‐stimulated neuronal cyclic GMP production. Furthermore, neuronal injury induced by exposure of cultures to H 2 O 2 was not altered by the presence of Dea/NO, indicating the absence of a direct antioxidant effect. NONO‐ates did, however, reduce NMDA‐stimulated uptake of 45 Ca 2+ , whereas high potassium‐induced 45 Ca 2+ accumulation, a measurement of entry via voltage‐gated calcium channels, was unaffected. The parallel reduction of 45 Ca 2+ accumulation and NMDA neurotoxicity by NONOates mimicked that seen with an NMDA receptor antagonist. Electrochemical measurements of NO via an NO‐sensitive electrode demonstrated that neuroprotective concentrations of all donors produced appreciable amounts of NO over the 5‐min time frame. Determination of the formation of NO + equivalents, as assessed by N ‐nitrosation of 2,3‐diaminonaphthylene, revealed little or no observable N ‐nitrosation by Sper/NO, GSNO, and SNAP with significant N ‐nitrosation observed by Papa/NO and Dea/NO. However, addition of ascorbate (400 μ M ) effectively prevented the nitrosation of 2,3‐diaminonaphthylene produced by Dea/NO and Papa/NO without altering their neuroprotective properties or their effects on 45 Ca 2+ accumulation. Present results indicate that the intrinsic NO/NO + characteristics of NO donor compounds may not be a good predictor of their ability to inhibit NMDA receptor‐mediated neurotoxicity at the cellular level.