Effects of the superoxide dismutase mimetic tempol on impaired endothelium-dependent and endothelium-independent relaxations in type II diabetic rats.
Endothelium-derived hyperpolarizing factor (EDHF)-mediated hyperpolarization and relaxation, and endothelium-independent relaxations to the nitric oxide donor sodium nitroprusside and the adenosine 5'-triphosphate (ATP)-sensitive K(+)-channel opener levcromakalim were both impaired in mesenteric arteries of type II diabetic Goto-Kakizaki rats. The treatment with the superoxide dismutase mimetic tempol or its combination with the angiotensin II type 1 receptor blocker candesartan failed to improve EDHF-mediated responses, although both treatments partially improved endothelium-independent relaxations. These findings suggest that increased oxidative stress may in part account for the impaired endothelium-independent relaxations in diabetes, while it does not play a major role in the impaired EDHF-mediated responses.
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Hideyuki
H
Oniki
Kenichi
K
Goto
Koji
K
Fujii
Yasuo
Y
Kansui
Noboru
N
Murakami
Toshio
T
Ohtsubo
Kiyoshi
K
Matsumura
Takanari
T
Kitazono
D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D003497:Cyclic N-Oxides / Q000378:metabolism / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000503:physiopathology; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology; D018716:Molecular Mimicry; D051381:Rats; D017208:Rats, Wistar; D013113:Spin Labels; D013482:Superoxide Dismutase / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
D000975:Antioxidants; D003497:Cyclic N-Oxides; D013113:Spin Labels; D013482:Superoxide Dismutase; C001803:tempol