Role of microvascular dysfunction in the cardiovascular center for development of hypertension

2015 Fiscal Year Final Research Report

• Project/Area Number: 26670413
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Cardiovascular medicine
• Research Institution: National Cardiovascular Center Research Institute
• Principal Investigator: Shirai Mikiyasu 国立研究開発法人国立循環器病研究センター, 研究所, 部長 (70162758)
• Co-Investigator(Kenkyū-buntansha): TSUCHIMOCHI HIROTSUGU 国立研究開発法人国立循環器病研究センター, 研究所, 室長 (60379948)
• Co-Investigator(Renkei-kenkyūsha): INAGAKI TADAKATSU 国立研究開発法人国立循環器病研究センター, 研究所, 上級研究員 (20638366)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 高血圧 / 交感神経活動 / 心臓血管中枢 / 延髄微小循環 / 高血圧自然発症ラット / 間歇的低酸素 / 肺循環

Outline of Final Research Achievements

We applied synchrotron radiation microangiography to young (4-week-old) spontaneously hypertensive rat (SHR) whose blood pressure is usually normal and found that arterioles in the medulla oblongata show abnormal responses (vasoconstriction) specifically with acute hypoxic exposure. In the unanesthetized young SHR, we measured renal and lumbar sympathetic nerve activity (SNA) for a month and found no significant SNA increase despite progressive rise in systemic blood pressure. In the chronic intermittent hypoxic rat, the SNA increased in proportion to blood pressure rise, but pulmonary SNA increase is not accompanied by pulmonary pressor response during acute hypoxic exposure. The inhibition of SNA increase with central β1 receptor blockade disclosed the hypoxic pulmonary pressor response, suggesting the SNA increase attenuates the hypoxic pulmonary response. These data suggest an important role of the ischemic state of the cardiovascular center for controlling SNA and blood pressure.

Free Research Field

循環生理学