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Endothelial nitric oxide synthetase (eNOS) in astrocytes: Another source of nitric oxide in neocortex
Author(s) -
Wiencken A.E.,
Casagrande V.A.
Publication year - 1999
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/(sici)1098-1136(199906)26:4<280::aid-glia2>3.0.co;2-w
Subject(s) - enos , nitric oxide , biology , neocortex , white matter , immunocytochemistry , astrocyte , cerebral cortex , nitric oxide synthase , microbiology and biotechnology , neuroglia , cortex (anatomy) , neuroscience , anatomy , endocrinology , central nervous system , medicine , radiology , magnetic resonance imaging
The distribution of the endothelial form of nitric oxide synthetase (eNOS) was examined in the visual cortex of three species of primate and in the rat using immunocytochemistry. Labeled cells were found in both the gray and white matter. These cells were stellate in appearance and labeled cell processes were seen contacting blood vessels or the pia, suggesting that, by morphological criteria, the cells were astrocytes. All eNOS positive cells were double labeled with an antibody against S100β. Although all cells were double labeled in the white matter, in the gray matter, some S100β positive cells did not contain detectable levels of eNOS. eNOS positive astrocytic processes appeared to form prominent and distinctive structures next to neurons, especially in cortical layer IIIC. We postulate that these eNOS‐positive structures form astrocytic perisynaptic sheaths on neuronal somas in the cortex. If this is true, then nitric oxide can influence neuronal transmission directly at axosomatic synapses in the cortex. In addition, the presence of eNOS in astrocytes and in their processes that contact blood vessels suggests that the link between local cortical activity and changes in cerebral blood flow could be mediated by astrocytic release of nitric oxide. GLIA 26:280–290, 1999. © 1999 Wiley‐Liss, Inc.