Nitric oxide synthase activity and inhibition after neonatal hypoxia ischemia in the mouse brain

Kanji Muramatsu, R. Ann Sheldon, Stephen M. Black, Martin Täuber, Donna M. Ferriero

Research output: Contribution to journalArticle

46 Scopus citations

Abstract

Despite the emergence of therapies for hypoxic-ischemic injury to the mature nervous system, there have been no proven efficacious therapies for the developing nervous system. Recent studies have shown that pharmacological blockade of neuronal nitric oxide synthase (nNOS) activity can ameliorate damage after ischemia in the mature rodent. We have previously shown that elimination of nNOS neurons, either by targeted disruption of the gene or by pharmacological depletion with intraparenchymal quisqualate, can decrease injury after hypoxia-ischemia. Using a simpler pharmacological approach, we studied the efficacy of a systemically administered NOS inhibitor, 7-nitroindazole, a relatively selective inhibitor of nNOS activity. Using multiple doses and concentrations administered after the insult, we found that there was only a trend for protection with higher doses of the drug. A significant decrease in NOS activity was seen at 18 h and 5 days in the cortex, and at 2 h and 18 h in the hippocampus after the hypoxia-ischemia. nNOS expression decreased and remained depressed for at least 18 h after the insult. When nNOS expression was normalized to MAP2 expression, a decrease was seen at 18 h in the cortex and at 2 and 18 h in the hippocampus. These data suggest that further inhibition of NOS activity at early timepoints may not provide substantial benefit. At 5 days after the insult, however, NOS activity and normalized nNOS expression returned to baseline or higher in the hippocampus, the region showing the most damage. These data suggest that delayed administration of nNOS inhibitor after hypoxic-ischemic injury might be beneficial. (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)119-127
Number of pages9
JournalDevelopmental Brain Research
Volume123
Issue number2
DOIs
StatePublished - Oct 28 2000

Keywords

  • Brain
  • Hypoxia-ischemia
  • Neonate
  • Neuronal nitric oxide synthase

ASJC Scopus subject areas

  • Developmental Neuroscience
  • Developmental Biology

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