Induction of nitric oxide synthase activity in human astrocytes by interleukin-1β and interferon-γ

Sunhee C. Lee, Dennis W. Dickson, Wei Liu, Celia F. Brosnan

Research output: Contribution to journalArticlepeer-review

355 Scopus citations


Nitric oxide (NO) is a short-lived, diffusible molecule that has a variety of biological activities including vasorelaxation, neurotransmission, and cytotoxicity. In the central nervous system, a constitutive form of nitric oxide synthase (NOS) has been localized in a subset of neurons and in endothelial cells. In addition, both constitutive and LPS-inducible NOS has been demonstrated in rat astrocytes and microglia in vitro. In this report, we present evidence for the production of NO, as measured by the production of nitrite, in highly enriched human fetal astrocyte cultures stimulated with IL-1β. The production of nitrite paralleled the induction of NADPH diaphorase enzyme activity in the perikarya of the majority of stimulated astrocytes. The IL-1β-induced nitrite production by astrocytes was markedly enhanced when cells were co-stimulated with IFN-γ or TNF-α (IFN-γ > TNF-α); LPS had no effect used as a single agent or in combination with other cytokines. NGMMA and NG-nitro-arginine, competitive inhibitors of NOS, diminished the accumulation of nitrite, but calmodulin antagonists (trifluoperazine, W-5 and W-7) had little or no inhibitory effect. Human fetal microglia, in contrast to astrocytes, failed to secrete significant amounts of nitrite in response to various stimuli. The results demonstrate the presence of an inducible form of NOS in human fetal astrocytes; human microglia, in turn, may control astrocyte NO production by providing IL-1β as an activating signal.

Original languageEnglish (US)
Pages (from-to)19-24
Number of pages6
JournalJournal of Neuroimmunology
Issue number1-2
StatePublished - Jul 1993
Externally publishedYes


  • Culture
  • Human astrocytes
  • Inducible nitric oxide synthase
  • Microglia
  • NADPH diaphorase
  • Nitric oxide

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Neurology
  • Clinical Neurology


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