Enhancement of Vasorelaxation in Hypertension Following High-Intensity Exercise

Ai-Lun Yang ； Chia-Wen Lo ； Jen-Ting Lee ； Chia-Ting Su

《The Chinese Journal of Physiology》 54卷2期 (2011/04) Pp. 87-95

https://doi.org/10.4077/CJP.2011.AMM011

並列摘要

Exercise can ameliorate vascular dysfunction in hypertension, but its underlying mechanism has not been explored thoroughly. We aimed to investigate whether the high-intensity exercise could enhance vasorelaxation mediated by insulin and insulin-like growth factor-1 (IGF-1) in hypertension. Sixteen-week-old spontaneously hypertensive rats were randomly divided into non-exercise sedentary (SHR) and high-intensity exercise (SHR+Ex) groups conducted by treadmill running at a speed of 30 m/min until exhaustion. Age-matched Wistar-Kyoto rats (WKY) were used as the normotensive control group. Immediately after exercise, the agonist-induced vasorelaxation of aortas was evaluated in organ baths with or without endothelial denudation. Selective inhibitors were used to examine the roles of nitric oxide synthase (NOS) and phosphatidylinositol-3 kinase (PI3K) in the vasorelaxation. By adding superoxide dismutase (SOD), a superoxide scavenger, the role of superoxide production in the vasorelaxation was also clarified. We found that, [1] the high-intensity exercise significantly (P＜0.05) induced higher vasorelaxant responses to insulin and IGF-1 in the SHR+Ex group than that in the SHR group; [2] after endothelial denudation and pre-treatment of the PI3K inhibitor, NOS inhibitor, or SOD, vasorelaxant responses to insulin and IGF-1 became similar among three groups; [3] the protein expression of insulin receptor, IGF-1 receptor, and endothelial NOS (eNOS) was significantly (P＜0.05) increased in the SHR+Ex group compared with the SHR group; [4] the relaxation to sodium nitroprusside, a NO donor, was not different among three groups. Our findings suggested that the high-intensity exercise ameliorated the insulin-and IGF-1-mediated vasorelaxation through the endothelium-dependent pathway, which was associated with the reduced level of superoxide production.

並列關鍵字

exercise ； vasorelaxation ； aorta ； nitric oxide ； superoxide

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