Roles of endothelial oxidases in endothelium-derived hyperpolarizing factor responses in mice.
The endothelium synthesizes and releases several vasodilator substances, including prostacyclin, nitric oxide (NO), and endothelium-derived hyperpolarizing factor (EDHF). We have demonstrated that endothelium-derived hydrogen peroxide (H2O2) is an EDHF in animals and humans and that superoxide anions derived from endothelial nitric oxide synthases (NOSs) system are an important precursor for EDHF/H2O2 in mice. There are several intracellular sources of superoxide anions other than NOSs, including NAD(P)H oxidase, xanthine oxidase, lipoxygenase, and mitochondrial electron transport chain. In this study, we examined the possible role of endothelial oxidases other than NOSs in the EDHF-mediated responses. In angiotensin II-infused mice, both EDHF-mediated relaxations and hyperpolarizations to acetylcholine were significantly reduced, nitric oxide-mediated relaxations were rather enhanced, and vascular smooth muscle responses were preserved. Antihypertensive treatment normalized blood pressure but failed to improve EDHF-mediated responses in those mice. Acute inhibition of endothelial oxidases other than NOSs, including NAD(P)H oxidase, xanthine oxidase, lipoxygenase, or mitochondrial electron transport chain, had no inhibitory effects on EDHF-mediated responses. Furthermore, in p47phox-knockout mice, EDHF-mediated responses were unaltered. These results suggest that endothelial oxidases other than NOSs are not involved in EDHF/H2O2 responses in mice, suggesting a specific link between endothelial NOSs system and EDHF responses under physiological conditions.
Takaki
Aya
A
Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
Morikawa
Keiko
K
Murayama
Yoshinori
Y
Yamagishi
Hiroto
H
Hosoya
Maki
M
Ohashi
Junko
J
Shimokawa
Hiroaki
H
D000804:Angiotensin II; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001685:Biological Factors / Q000378:metabolism*; D001794:Blood Pressure; D002374:Catalase / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005979:Glutathione Peroxidase / Q000378:metabolism; D006973:Hypertension / Q000139:chemically induced / Q000188:drug therapy / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D000959:Antihypertensive Agents; D001685:Biological Factors; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; C067410:endothelium-dependent hyperpolarization factor; D013481:Superoxides; D000804:Angiotensin II; D010088:Oxidoreductases; D002374:Catalase; D005979:Glutathione Peroxidase; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1