Coronary vascular dysfunction promoted by oxidative-nitrative stress in SHRSP.Z-Lepr(fa) /IzmDmcr rats with metabolic syndrome.
1. Metabolic syndrome is an independent risk factor for cardiovascular disease. SHRSP.Z-Lepr(fa) /IzmDmcr (SHRSP fatty) rat, established as a new rat model of metabolic syndrome, spontaneously develops obesity, severe hypertension and shows hypertriglyceridaemia, hypercholesterolaemia and abnormal glucose tolerance. Using SHRSP fatty rats, we examined whether or not oxidative stress was correlated with vascular dysfunction in small and large calibre coronary arteries in ex vivo beating hearts, isolated mesenteric arteries and aortas in comparison with normal rats, Wistar-Kyoto rats (WKY). Vasodilation of coronary arteries was determined by microangiography of the Langendorff heart. 2. Compared with WKY, acetylcholine (ACh) and sodium nitroprusside (SNP)-induced relaxations were impaired in the coronary arteries of SHRSP fatty rats. The mesenteric arteries and aorta of SHRSP fatty rats showed impaired relaxation responses to ACh and SNP, decreased 3',5'-monophosphate (cGMP) production, and reduced soluble guanylyl cyclase protein expression. Superoxide release, angiotensin II and 3-nitrotyrosine contents were increased. 3. SHRSP fatty rats were orally administered olmesartan, an angiotensin II receptor type 1 (AT(1) ) antagonist, and amlodipine, a calcium channel blocker, at doses of 5 and 8mg/kg per day, respectively, for 8weeks. Both olmesartan and amlodipine reduced blood pressure, but only olmesartan prevented the development of abnormal vascular and biochemical parameters in the SHRSP fatty rats. 4. The results showed that in the SHRSP fatty rats, the impaired nitric oxide- and cGMP-mediated relaxation of vascular smooth muscle cells were linked to AT(1) receptor-induced oxidative-nitrative stress, which occurred concurrently with severe hypertension and metabolic abnormalities in vivo.
Kagota
Satomi
S
Department of Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, Japan. skagota@mukogawa-u.ac.jp
Fukushima
Kazuhito
K
Umetani
Keiji
K
Tada
Yukari
Y
Nejime
Namie
N
Nakamura
Kazuki
K
Mori
Hidezo
H
Sugimura
Kazuro
K
Kunitomo
Masaru
M
Shinozuka
Kazumasa
K
D000109:Acetylcholine / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood; D024821:Metabolic Syndrome / Q000150:complications* / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D009569:Nitric Oxide / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D047228:Angiotensin II Type 1 Receptor Blockers; D001786:Blood Glucose; D002121:Calcium Channel Blockers; D007328:Insulin; D008055:Lipids; D000804:Angiotensin II; D009599:Nitroprusside; D009569:Nitric Oxide; D006152:Cyclic GMP; D000109:Acetylcholine