Neuronal nitric oxide synthase inhibitor has a neuroprotective effect in arat model of brain injury

Purpose: The aim of the present study was to assess the effects of neuronal nitric oxide synthase (NOS I) inhibitors and a combination of NOS I and NO S II inhibitors on lesion volume after experimental brain injury. Methods: Cold lesion of the brain was induced by application of a precooled (-78 degreesC) copper cylinder to the intact dura of the rat for 6 s. Brai ns were removed 24 h after the injury and lesion volume determined using th e triphenyltetrazolium-chloride method. Results: The specific NOS I inhibitor 3-bromo-7-nitroindazole (Br-7-NI) red uced lesion volume significantly by 21 % compared with the vehicle control. In contrast, 7-nitroindazole had no effect on lesion volume. When aminogua nidine, a specific NOS II inhibitor, was administered after Br-7-NI, lesion volume was significantly reduced but not significantly more than with eith er compound alone. Conclusion: Brain injury after cold lesion is partly mediated by NOS I acti vity and can be attenuated successfully with Br-7-NI, while coinhibition of NOS II does not improve the outcome significantly.