Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Oxygen radicals like superoxide anions (O2-) or nitric oxide (NO), have been associated with various neurodegenerative diseases. A cytosolic constitutively expressed CuZn superoxide dismutase (SOD) and a mitochondria specifically located inducible MnSOD catalyse the dismutation of O2-. NO is the product of nitric oxide synthase which exists as a constitutive cNO synthase and an inducible iNO synthase. These radicals may react together to form peroxinitrite. Therefore we examined MnSOD, iNO synthase and nitrotyrosine (NT) distribution within rat glial cells in primary culture. Flat polygonal shaped astrocytes, highly immunostained for glial fibrillary acid protein, express significant MnSOD staining. Microglial cells also express an intense MnSOD signal. On the contrary, oligodendro- glial cells in secondary culture, well characterizd by their 2',3'-cyclic nucleotide 3' phosphodiesterase immunoreactivity, never express any immunostaining for MnSOD. Likewise bipotential A2B5-positive O-2A precursors do not express any MnSOD signal. Inducible NOs was exclusively observed in some microglial cells in response to lipopolysaccharide treatment. NT was localized in a fraction of the microglial and of the astroglial population. Our observations suggest that NO may diffuse from microglia to surrounding astrocytes and compete with SOD for O2- to generate peroxinitrite and to produce by nitrosylation some modifications in regulatory or structural proteins. .

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Presentation Number SAperraut,m.0192
Keywords: superoxide, NO synthase, astrocyte, microglia, nitrosylation