title: Rho-kinase contributes to hypoxia/reoxygenation-induced cerebral endothelial dysfunction.
abstract: Hypoxia/reoxygenation (H/R) in vitro induced cerebral endothelial dysfunction is mediated by superoxide production. However, the intracellular pathways involved remain unclear. The present study was designed to investigate the involvement of Rho-kinase and its interaction with nitric oxide (NO) in cerebral endothelial dysfunction after H/R. Arterial diameter and intraluminal pressure were simultaneously measured in vitro on rat posterior cerebral arteries. Vascular NO production was determined by measuring stable NO metabolites nitrate/nitrite. H/R selectively inhibited cerebral vasodilation to the endothelium-dependent agonist acetylcholine (ACh, 0.01 to 10 micromol/L) and caused NO deficiency. H/R-impaired vasodilation to ACh was reversed by Y27632 (1 micromol/L), a specific inhibitor of Rho-kinase, but not by chelerythrine (1 micromol/L), a selective inhibitor of protein kinase C. Y27632 had no protective effect in the presence of N-nitro-L-arginine methyl ester (L-NAME; 100 micromol/L), a specific endothelial NO synthase inhibitor. L-NAME (100 micromol/L) alone failed to modulate H/R-impaired vasodilation, so did L-arginine (3 mmol/L), a substrate for NO synthase. However, a stable NO donor diethylenetetra amine-NONOate (5 micromol/L) normalized H/R-impaired dilation to ACh. In conclusion, H/R-induced endothelial dysfunction is associated with activation of Rho-kinase-dependent pathway and NO deficiency. Pretreatment with either Y27632 or the stable NO donor profoundly prevented H/R-mediated cerebral endothelial dysfunction.
authors.affiliation: Department of Neonatology, Children's Research Institute, Children's National Medical Center, The George Washington University, Washington, DC 20010, USA. hxie@cnmc.org
authors.forename: Hui
authors.initials: H
authors.lastname: Xie
authors.forename: Patricio E
authors.initials: PE
authors.lastname: Ray
authors.forename: Billie Lou
authors.initials: BL
authors.lastname: Short
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000470:Alkaloids; D000577:Amides / Q000494:pharmacology; D000818:Animals; D053119:Benzophenanthridines; D002536:Cerebral Arteries / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000860:Hypoxia / Q000503:physiopathology; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010100:Oxygen / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism; D014226:Triazenes / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology; D054460:rho-Associated Kinases
chemical_list: C105351:1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene; D000470:Alkaloids; D000577:Amides; D053119:Benzophenanthridines; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D010617:Phenanthridines; D011725:Pyridines; D014226:Triazenes; D014665:Vasodilator Agents; D013481:Superoxides; C108830:Y 27632; D009569:Nitric Oxide; C016299:chelerythrine; D019001:Nitric Oxide Synthase; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D000109:Acetylcholine; D010100:Oxygen; D019331:NG-Nitroarginine Methyl Ester