Barry D I, Strandgaard S, Graham D I, Braendstrup O, Svendsen U G, Vorstrup S, Hemmingsen R, Bolwig T G
J Cereb Blood Flow Metab. 1982 Sep;2(3):347-53. doi: 10.1038/jcbfm.1982.35.
The effect of chronic hypertension on cerebral blood flow (CBF) was studied in anaesthetised rats. CBF was measured with the intracarotid 133Xe injection method. Rats with spontaneous and renal hypertension were compared with normotensive controls. The lower limit of autoregulation was determined during controlled haemorrhage. In the normotensive rats, CBF remained constant until mean arterial pressure (MAP) had decreased to the range of 50-69 mm Hg. Thereafter, CBF decreased with each further decrease in MAP. In both types of hypertensive rats, CBF remained constant until MAP had decreased to the range of 70-89 mm Hg. Thus, a 20-mm Hg shift of the lower limit of CBF autoregulation was found in both spontaneous and renal hypertensive rats. A neuropathological study revealed ischaemic brains lesions in half of the hypertensive rats following hypotension, whereas only a single lesion was found in one of six normotensive rats. No ischaemic brain lesions were found in a control study in which CBF was shown to be stable over a 21/2-h period. In conclusion, hypertensive rats showed a shift of the lower limit of CBF autoregulation as well as an increased susceptibility to ischaemic brain damage during hypotension. These findings presumably reflect hypertensive structural changes in the cerebral circulation.
在麻醉大鼠中研究了慢性高血压对脑血流量（CBF）的影响。采用颈内动脉注射¹³³Xe法测量CBF。将自发性高血压大鼠和肾性高血压大鼠与正常血压对照组进行比较。在控制性出血过程中确定自动调节下限。在正常血压大鼠中，直到平均动脉压（MAP）降至50 - 69 mmHg范围之前，CBF保持恒定。此后，随着MAP的进一步降低，CBF也随之下降。在两种类型的高血压大鼠中，直到MAP降至70 - 89 mmHg范围之前，CBF保持恒定。因此，在自发性高血压大鼠和肾性高血压大鼠中均发现CBF自动调节下限有20 mmHg的偏移。神经病理学研究显示，低血压后一半的高血压大鼠出现缺血性脑损伤，而在六只正常血压大鼠中仅一只发现单个损伤。在一项对照研究中未发现缺血性脑损伤，该研究显示CBF在2.5小时内保持稳定。总之，高血压大鼠表现出CBF自动调节下限的偏移以及低血压期间对缺血性脑损伤的易感性增加。这些发现可能反映了脑循环中的高血压结构变化。
