• Kana Tsukuda, Masaki Mogi, Jian-Mei Li, Jun Iwanami, Li-Juan Min, Akiko Sakata, Teppei Fujita, Masaru Iwai, and Masatsugu Horiuchi.
• Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Shitsukawa, Tohon, Ehime 791-0295, Japan.
• Hypertension. 2007 Dec 1;50(6):1099-105.

AbstractAngiotensin II type-1 receptor blockers are widely used with the expectation of prevention of stroke, potential effects to ameliorate of type-2 diabetes, which seems to be closely associated with the impairment of cognitive function in humans. Recently, we have reported that an angiotensin II type-1 receptor blocker prevented cognitive impairment in mice after focal cerebral ischemia, at least partly through an angiotensin II type-2 receptor-mediated increase in a neuroprotective factor, methyl methanesulfonate sensitive-2. Here, we examined the possibility that an angiotensin II type-1 receptor blocker could improve cognitive function in a type-2 diabetic mouse model, KK-A(y). KK-A(y) mice subjected to 20 trials of a passive avoidance task every week from 8 weeks exhibited a significantly impaired avoidance rate, and moreover, its age-dependent decline, especially after 14 weeks of age, compared with age-matched C57BL6 mice. Oral administration of candesartan at a nonhypotensive dose (0.005% in laboratory chow) in KK-A(y) mice improved cognitive function and inhibited the impairment of cognitive decline. Methyl methanesulfonate sensitive-2 expression in the brain was lower in KK-A(y) mice than in C57BL6 mice. Treatment with candesartan markedly increased mRNA expression of angiotensin II type-2 receptor and methyl methanesulfonate sensitive-2 in the brain in KK-A(y) mice, determined by quantitative RT-PCR. In KK-A(y) mice treated with candesartan, age-dependent increases in blood glucose and insulin were significantly suppressed. Our results suggest that candesartan ameliorates the impaired cognitive function in type-2 diabetes mice, at least because of an increased expression of methyl methanesulfonate sensitive-2, a neuroprotective factor, in addition to improvement of glucose intolerance.

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