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ABSTRACT: Aging is an independent risk factor for hypertension, and hypertension and insulin resistance commonly coexist in the elderly. This study was designed to examine the effects of aging-related insulin resistance on blood pressure (BP) and its underlying mechanisms, with specific focus on the role of exercise in reversing hypertensive response. Adult (6-month-old) and aging (24-month-old) male Sprague-Dawley rats were subjected to a 10 weeks free-of-loading swim training (60 min/day, 5 days/week). Arterial vasorelaxation, cardiac contraction, eNOS activation, and iNOS and gp91(phox) expression were determined. Under aging-related insulin resistance conditions, insulin infusion significantly elevated BP (P < 0.05). Aging caused significant endothelial dysfunction (P < 0.05 - 0.01), which was responsible for decreased arterial vasorelaxation to insulin. Aging attenuated myocardial contractile response to insulin, decreased eNOS expression and its phosphorylation by insulin, and increased iNOS and gp91(phox) expression in aging arteries (P < 0.01). Exercise improved insulin sensitivity, potentiated insulin's positive inotropic effects, facilitated arterial vasorelaxation to insulin, increased arterial eNOS activation in adult and aging rats, and thus attenuated insulin resistance-related hypertensive response to insulin. Moreover, exercise markedly reversed increased iNOS and gp91(phox) expression in aging arteries. Inhibition of eNOS with Cavtratin or L-NAME significantly blocked exercise-facilitated arterial vasorelaxation to insulin and exercise-lowered BP response to insulin. In conclusion, these results demonstrate that endothelial dysfunction in response to insulin, but not insulin's positive inotropic effects, plays an important role in the development of aging-related hypertension. The reversal of hypertensive response to insulin by exercise is most likely associated with improved insulin sensitivity in an eNOS-dependent manner and reduced oxidative and nitrative stresses.
Archiv für Kreislaufforschung 10/2008; 104(3):269-84. · 7.35 Impact Factor
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ABSTRACT: By genechip cDNA microarray, the genes expressions of Stearoyl-coenzyme A desaturase (Scd-2) and brain fatty acid-binding protein (B-FABP) were studied in the central nervous system (CNS) of the mice to discuss the mechanism of exercise-induced fatigue.
Building the model of fatigued animal and using the genechip cDNA microarray, the genes expressions were analyzed between the control group and fatigue group mice.
The genes expression of Scd-2 and B-FABP were obvious different in the brain of fatigued group mice than of control group.
Exercise-induced nerve center fatigue is correlated with genes expressions of lipid metabolism.
Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology 05/2005; 21(2):137-9.
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ABSTRACT: To observe possible mechanism that endurance training can enhance anti-fatigue capability, and that blood redistribution by analyzing some biochemical indexes of endurance-trained mice after exhaustive exercise.
The model was set up by exhaustive exercise. The indexes include the activity of SOD, CAT and POD and the MDA content in serum and the NO content in liver, muscle, heart and serum.
After exhaustive exercise, the SOD activity in serum and the NO content in liver significantly decrease (P < 0.05 - 0.01), and the activity of POD and CAT, the NO content in serum and muscle significantly increase (P < 0.05 - 0.01), but the rest insignificantly change in non-endurance (P > 0.05). In endurance group, the CAT activity in serum are significantly higher than in non-endurance (P < 0.05), and the NO content in serum is significantly lower than in non-endurance (P < 0.01), but the rest are insignificantly different between two groups (P > 0.05). After 24h restoration, in non-endurance group, the CAT activity and the MDA content in serum and the NO content in liver significantly rise (P < 0.05-0.01), and the NO content in muscle and serum significantly decrease (P < 0.05), but the rest insignificantly change (P > 0.05). In endurance group, the SOD activity in serum and the NO content in liver, serum and heart significantly rise (P < 0.05), and the CAT activity in serum significantly decreases (P < 0.05), but the rest insignificantly change (P > 0.05). In endurance group, the CAT activity and the MDA content in serum are significantly lower than in non-endurance (P < 0.05), but the NO content in heart is higher than in non-endurance (P < 0.05). The rest are insignificantly different between two groups (P > 0.05).
The possible mechanism, which endurance training can enhance anti-fatigue capability, is relative to enhance the capability to resume balance. Blood redistribution are possibly relative to change to the NO content.
Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology 11/2003; 19(4):363-6.
