Weiss H R, Buchweitz-Milton E
Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854-5635.
Eur J Pharmacol. 1988 Mar 22;148(1):107-13. doi: 10.1016/0014-2999(88)90459-1.
This study assessed the role of vascular and central alpha-adrenoceptors in the regional cerebral blood flow response to moderate hypoxia. Studies were conducted in 21 rabbits using radioactive microspheres under normoxic and hypoxic (10% O2 in N2) conditions. Animals were divided into three groups and administered either saline, N-methyl chlorpromazine, or phenoxybenzamine. During normoxia, there were regional differences in cerebral blood flow distribution in the saline- and N-methyl chlorpromazine-treated rabbits which were eliminated by phenoxybenzamine. In control, hypoxia significantly increased average cerebral blood flow from 57 +/- 22 to 132 +/- 52 ml/min per 100 g. Flow to the hindbrain increased to a significantly greater extent than to the mid- or forebrain during hypoxia. The increase in average cerebral blood flow during hypoxia was significantly reduced to 97 +/- 34 ml/min per 100 g by phenoxybenzamine. Both alpha-adrenoceptor antagonists prevented the significantly greater increase in hindbrain flow during hypoxia. The greater flow responsiveness of the hindbrain to hypoxia appears to be related at least in part to alpha-adrenoceptors found in the cerebral vasculature.
本研究评估了血管和中枢α-肾上腺素能受体在大脑局部血流对中度缺氧反应中的作用。在21只家兔身上进行了研究，采用放射性微球技术，分别在常氧和低氧（氮气中10%氧气）条件下进行。动物被分为三组，分别给予生理盐水、N-甲基氯丙嗪或酚苄明。在常氧状态下，生理盐水组和N-甲基氯丙嗪组家兔的脑血流分布存在区域差异，而酚苄明可消除这种差异。在对照组中，缺氧显著增加平均脑血流量，从每100克57±22毫升/分钟增加到132±52毫升/分钟。缺氧期间，后脑血流量的增加幅度明显大于中脑或前脑。酚苄明使缺氧期间平均脑血流量的增加显著降低至每100克97±34毫升/分钟。两种α-肾上腺素能受体拮抗剂均能阻止缺氧期间后脑血流量的显著增加。后脑对缺氧的血流反应性增强似乎至少部分与脑血管中的α-肾上腺素能受体有关。
