Hudetz A G, Roman R J, Harder D R
Department of Physiology, Medical College of Wisconsin, Milwaukee 53226.
J Cereb Blood Flow Metab. 1992 May;12(3):491-9. doi: 10.1038/jcbfm.1992.67.
The purpose of this study was to characterize spontaneous oscillations of blood flow in the cerebral cortex of anesthetized rats under control conditions and after mean arterial pressure was altered by various means. Blood flow was monitored using a laser-Doppler flowmeter through the closed cranium. Spontaneous flow oscillations with amplitudes of 14-30% of the mean flow and frequencies of 4-11 cycles/min were recorded when arterial pressures were less than 90 mm Hg. Stepwise hemorrhagic hypotension and unilateral carotid occlusion increased the amplitude of oscillations. The amplitude of oscillations was negatively correlated with the level of mean arterial pressure after manipulation with norepinephrine or sodium nitroprusside. The oscillations were reversibly abolished during dilation of the cerebral circulation by elevating the inspired carbon dioxide content to 5%. The frequency of flow oscillations was very stable during all of the above maneuvers except during the infusion of norepinephrine, which increased the oscillation frequency slightly. The results suggest that flow oscillations are determined primarily by cerebral arterial pressure.
本研究的目的是在对照条件下以及通过各种方法改变平均动脉压后，对麻醉大鼠大脑皮质中血流的自发振荡进行特征描述。使用激光多普勒血流仪通过闭合的颅骨监测血流。当动脉压低于90 mmHg时，记录到平均血流幅度为14%-30%、频率为4-11次/分钟的自发血流振荡。逐步出血性低血压和单侧颈动脉闭塞增加了振荡幅度。在用去甲肾上腺素或硝普钠处理后，振荡幅度与平均动脉压水平呈负相关。通过将吸入二氧化碳含量提高到5%使脑循环扩张时，振荡可逆性消失。除了输注去甲肾上腺素时振荡频率略有增加外，在上述所有操作过程中，血流振荡频率非常稳定。结果表明，血流振荡主要由脑动脉压决定。
