title: Effects of simulated microgravity on arterial nitric oxide synthase and nitrate and nitrite content.
abstract: The aim of the present work was to investigate the alterations in nitric oxide synthase (NOS) expression and nitrate and nitrite (NOx) content of different arteries from simulated microgravity rats. Male Wistar rats were randomly assigned to either a control group or simulated microgravity group. For simulating microgravity, animals were subjected to hindlimb unweighting (HU) for 20 days. Different arterial tissues were removed for determination of NOS expression and NOx. Western blotting was used to measure endothelial NOS (eNOS) and inducible NOS (iNOS) protein content. Total concentrations of NOx, stable metabolites of nitric oxide, were determined by the chemiluminescence method. Compared with controls, isolated vessels from simulated microgravity rats showed a significant increase in both eNOS and iNOS expression in carotid arteries and thoracic aorta and a significant decrease in eNOS and iNOS expression of mesenteric arteries. The eNOS and iNOS content of cerebral arteries, as well as that of femoral arteries, showed no differences between the two groups. Concerning NOx, vessels from HU rats showed an increase in cerebral arteries, a decrease in mesenteric arteries, and no change in carotid artery, femoral artery and thoracic aorta. These data indicated that there were differential alterations in NOS expression and NOx of different arteries after hindlimb unweighting. We suggest that these changes might represent both localized adaptations to differential body fluid redistribution and other factors independent of hemodynamic shifts during simulated microgravity.
authors.affiliation: Department of Pharmacology, College of Medicine, University of California, Irvine 92697-4625, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Ma
authors.forename: Chadi I
authors.initials: CI
authors.lastname: Kahwaji
authors.forename: Zhenmin
authors.initials: Z
authors.lastname: Ni
authors.forename: Nosratola D
authors.initials: ND
authors.lastname: Vaziri
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Purdy
mesh_terms: D000818:Animals; D001158:Arteries / Q000378:metabolism*; D019417:Hindlimb Suspension; D008297:Male; D009566:Nitrates / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018474:Weightlessness Simulation
chemical_list: D009566:Nitrates; D009573:Nitrites; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat