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Olmesartan reduces oxidative stress in the brains of stroke‐prone spontaneously hypertensive rats as measured by an in vivo ESR method
Author(s) -
Araki Shuichiro,
Hirooka Yoshitaka,
Koga Yasuaki,
Ito Koji,
Kishi Takuya,
Yasukawa Keiji,
Utsumi Hideo,
Sunagawa Kenji
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.738.5
Subject(s) - olmesartan , in vivo , oxidative stress , endocrinology , medicine , blood pressure , hydralazine , hydrochlorothiazide , excretion , angiotensin ii , chemistry , pharmacology , biology , microbiology and biotechnology
Background : We previously demonstrated that oxidative stress is involved in the neural mechanisms of hypertension. In the present study, we evaluated the effects of anti‐hypertensive treatment with the angiotensin type 1 receptor blocker olmesartan on oxidative stress in the brains of stroke‐prone spontaneously hypertensive rats (SHRSP) using the in vivo electron spin resonance (ESR)/spin probe technique.Methods and Results : Two groups of 12‐week‐old SHRSP were treated with either olmesartan (10 mg/kg/day) or hydralazine (Hyd, 20 mg/kg/day)/hydrochlorothiazide (HCT, 4.5 mg/kg/day) for 30 days (n=5 for each). Systolic blood pressure decreased after each treatment (151±8 mm Hg [olmesartan] and 156±13 mm Hg [Hyd/HCT], NS). In rats treated with Hyd/HCT, but not those treated with olmesartan, heart rate and urinary norepinephrine excretion increased. The in vivo ESR signal decay rates of the blood‐brain barrier‐permeable spin probe, methoxycarbonyl‐PROXYL, were significantly higher in SHRSP brains compared with age‐matched normotensive Wistar‐Kyoto rat brains (0.121±0.010 vs 0.098±0.011/min, P < 0.01, n=6 for each). Olmesartan attenuated the ESR signal decay rates in SHRSP brains, but Hyd/HCT did not.Conclusions : These results suggest that olmesartan has an anti‐oxidative effect in SHRSP brains, as measured by an in vivo ESR method, in addition to its blood pressure‐lowering effects.