Nitric oxide and S-nitrosylation: excitotoxic and cell signaling mechanism.

This review focuses on the important physiological messenger, nitric oxide (NO), and its role in N-methyl-D-aspartate (NMDA) excitotoxicity. NO has been shown to be a key mediator of voltage-gated Ca(+2) transmembrane proteins. It remains unclear whether NO is implicated during hypoxia, or ischemic/reperfusion injuries as a neuroprotective or neurodegenerative factor. Excitotoxicity results from the excessive stimulation of excitatory glutamate receptors within the CNS. This review maintains that the feed-forward pathway precipitated by oxidative stress is the discriminating factor in the neuroprotective or neurodegenerative actions of NO.