Nitric oxide synthase and NADPH-diaphorase after acute hypobaric hypoxia in the rat caudate putamen

• Published in: Experimental neurology 2004-03, Vol.186 (1), p.33-45
• Main Authors: Encinas, Juan Manuel, Fernández, Ana Patricia, Salas, Eduardo, Castro-Blanco, Susana, Muñoz, Priscila, Rodrigo, José, Serrano, Julia
• Format: Article
• Language: English
• Subjects: Altitude; Animals; Biological and medical sciences; Blood Vessels - cytology; Blood Vessels - enzymology; Blotting, Western - methods; Cell Count; Endothelial and inducible nitric oxide synthase; Endothelium - cytology; Endothelium - enzymology; High altitude; Hypoxia - enzymology; Immunohistochemistry - methods; Injuries of the nervous system and the skull. Diseases due to physical agents; Male; Medical sciences; NADPH Dehydrogenase - metabolism; Neostriatum - cytology; Neostriatum - enzymology; Neurology; Neuronal; Neurons - enzymology; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Rats; Rats, Wistar; Striatum; Time Factors; Traumas. Diseases due to physical agents; Tyrosine - analogs & derivatives; Tyrosine - metabolism; Vascular diseases and vascular malformations of the nervous system
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/j.expneurol.2003.09.024

Changes in the production system of nitric oxide (NO), a multifunctional biological messenger known to participate in blood-flow regulation, neuromodulation, and neuroprotection or neurotoxicity, were investigated in the caudate putamen of adult rats submitted to hypobaric hypoxia. Employing immunohistochemistry, Western blotting, enzymatic assay, and NADPH-diaphorase staining, we demonstrate that neuronal nitric oxide synthase (nNOS) expression and constitutive nitric oxide synthase (cNOS) activity were transiently activated by 7 h of exposure to a simulated altitude of 8325 m (27,000 ft). In addition, endothelial nitric oxide synthase (eNOS) immunoreactivity and blood vessel NADPH-diaphorase staining peaked immediately after the hypoxic stimulus, whereas inducible nitric oxide synthase (iNOS) expression and activity remained unaltered. Nitrotyrosine formation, a marker of protein nitration, was evaluated by immunohistochemistry and Western blotting, and was found to increase parallel to nitric oxide synthesis. We conclude that the nitric oxide system undergoes significant transient alterations in the caudate putamen of adult rats submitted to acute hypobaric hypoxia.