Immunocytochemical localization of endothelial nitric oxide synthase (e-NOS) and inducible nitric oxide synthase (i-NOS) in rat neurohypophysis after transient cerebral ischemia

• Published in: Folia neuropathologica Vol. 37; no. 1; pp. 10 - 19
• Main Authors: Gajkowska, B, Viron, A, Cholewiński, M
• Format: Journal Article
• Language: English
• Published: Poland 1999
• Subjects: Animals; Brain - blood supply; Brain - enzymology; Cerebral Arteries - enzymology; Endothelium - enzymology; Enzyme Induction; Immunohistochemistry; Ischemic Attack, Transient - enzymology; Male; Mast Cells - enzymology; Mast Cells - ultrastructure; Nitric Oxide Synthase - biosynthesis; Pituitary Gland, Posterior - enzymology; Pituitary Gland, Posterior - ultrastructure; Rats; Rats, Wistar; Stimulation, Chemical; Vasodilation - physiology
• ISSN: 1641-4640

The expression pattern of endothelial and inducible forms of nitric oxide synthase (e-NOS, i-NOS) in rat neurohypophysis after transient ischemia was investigated using post-embedding immunogold method. We demonstrate that ischemia induced an early (10 min) expression of e-NOS not only in endothelium but also in the mast cells. Expression of i-NOS was almost exclusively confined to glial cells (pituicytes) and perivascular macrophages of experimental animals, and peaked at 24 h after ischemia. This evidence indicates that NO plays a significant role in mechanisms of cerebral ischemia. Taking into account the known beneficial role of e-NOS in ischemia it is likely that mast cells protect against post-ischemic brain damage by producing vasodilatation via nitric oxide. In contrast, cerebral macrophages and pituicytes may mediate neuronal and endothelial damage in late period after ischemia in rat neurohypophysis.