INCREASE IN NITRIC-OXIDE IN THE HYPOXIC-ISCHEMIC NEONATAL RAT-BRAIN AND SUPPRESSION BY 7-NITROINDAZOLE AND AMINOGUANIDINE

We measured the changes in nitric oxide (NO) metabolites in the brains of neonatal rats with hypoxic-ischemic damage. There were two peaks o f NO metabolites in the lesioned side of the cortex without treatment: one during hypoxia and the other during the re-oxygenation period. Pr ehypoxic treatment with 7-nitroindazole, a selective neuronal NO synth ase inhibitor, suppressed both peaks of NO metabolites, whereas prehyp oxic treatment with aminoguanidine, a selective inducible NO synthase inhibitor, partially suppressed only the peak in the re-oxygenation pe riod. These data suggest different roles of neuronal and inducible NO synthases in the pathogenesis of hypoxic-ischemic encephalopathy. (C) 1998 Elsevier Science B.V.