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Induction of endothelial nitric oxide synthase in perivascular mast
cells in rat neurohypophysis after ischemia
by Barbara Gajkowska & Robert Gniadecki
Key
words:
brain ischemia, endothelial
nitric oxide synthase, mast cells
Abstract
An electron microscopic immunocytochemical
study was performed in order to determine the expression pattern
of endothelial nitric oxide synthase (eNOS) in rat neurohypophysis
after ischemia. In basal conditions eNOS was found to be weakly
expressed on the endothelial cells and on single activated neurohypophyseal
mastocytes. After cerebral ischemia, the number of mast cells
increased in the neurohypophysis. The eNOS immunolabelling of
mast cells was strongly enhanced between 10 min and 3 h after
ischemia and declined at 24 h after ischemia. eNOS labelling
was also enhanced in endotethelial cells between 30 min and
3 h after ischemia. Ultrastructurally, eNOS labelling was restricted
to the granules of activated mast cells and the cytoplasm of
endothelial cells. This study suggests that cerebral mastocytes
are an important source of eNOS in neurohypophysis during ischemia
and contribute to nitric oxide production in the perivascular
space.
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