The effect of norepinephrine on the coronary microcirculation.
The effect of norepinephrine on the coronary microcirculation.
复制标题
去甲肾上腺素对冠状动脉微循环的影响。
DOI：
10.1159/000158924
复制
发表时间：
1992
影响因子：
1.7
通讯作者：
Harrison,D
中科院分区：
文献类型：
--
作者：
Quillen,J;Sellke,F;Banitt,P;Harrison,D
交感神经系统在调节大冠状动脉张力中的作用已经被很好地确定了。对冠状动脉阻力血管的肾上腺素能调节的研究在很大程度上局限于基于活体血流测量的间接推断。本研究的目的是用直接体外方法确定去甲肾上腺素(NE)对冠脉微循环的影响。猪冠状动脉微血管(直径80~200微米)在隔离器官腔内加压。使用Halpern微血管成像仪测量直径。用白三烯D4预收缩后，去甲肾上腺素可完全松弛。心得安可抑制去甲肾上腺素的松弛作用。去除cGMP的LY83583和结合内皮衍生的松弛因子EDRF的血红蛋白也能抑制去甲肾上腺素的松弛。即使在血红蛋白和心得安存在的情况下，NE在预缩窄和非预缩窄的微血管中也引起轻微的收缩或没有收缩。总之，去甲肾上腺素主要通过激活β肾上腺素能受体和刺激内源性血管内皮生长因子的释放来扩张猪冠状动脉微血管。α受体介导的微小冠脉微血管收缩。
The role of the sympathetic nervous system in the regulation of large coronary artery tone has been well defined. Studies of adrenergic regulation of coronary-resistance vessels have largely been limited to indirect inferences based on flow measurement obtained in vivo. The purpose of the present study was to determine the effects of norepinephrine (NE) on the coronary microcirculation using direct in vitro approaches. Porcine coronary microvessels (80-200 µm in diameter) were pressurized in isolated organ chambers. Diameters were measured using a Halpern microvessel imaging apparatus. After preconstriction with leukotriene D4, NE caused complete relaxation. Relaxations to NE were inhibited by propranolol. Relaxations to NE were also inhibited by LY83583 (which depletes cGMP) and hemoglobin (which binds endothelium-derived relaxing factor, EDRF). NE caused minimal or no constriction in both preconstricted and nonpreconstricted microvessels even in the presence of hemoglobin and propranolol. In conclusion, NE predominantly dilates porcine coronary microvessels, both by β-adrenoceptor activation and by stimulating release of EDRF. There is minimal α-adrenoceptor-mediated constriction of coronary microvessels.