Tanaka S, Tanaka M, Akashi A
Research Institute, Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan.
Stroke. 1989 Dec;20(12):1724-9. doi: 10.1161/01.str.20.12.1724.
We studied the effect of chronic antihypertensive treatment with budralazine on the lower blood pressure limit of cerebral blood flow autoregulation using spontaneously hypertensive rats. Cerebral blood flow in the parietal cortex and caudate nucleus was measured to determine the lower limit using the hydrogen clearance method. The lower limit in both cerebral regions was significantly higher in 10 untreated spontaneously hypertensive rats than in 10 Wistar-Kyoto rats. The upward-shifted lower limit was restored to close to normal in the caudate nucleus and was partially restored in the parietal cortex of nine rats by 9 weeks of treatment with the high dose (50-68 mg/kg/day) of budralazine, which kept blood pressure constant at approximately normotension during the treatment period; the lower limit was slightly restored in both cerebral regions of seven rats by 4 weeks of treatment with the high dose. However, 9 weeks of treatment with the low dose (19-27 mg/kg/day) of budralazine, which produced moderate continuous hypotension in nine rats, did not apparently influence the lower limit. Our results suggest that long-term antihypertensive therapy with budralazine reduces the upward-shifted lower blood pressure limit of cerebral blood flow autoregulation toward normal and that the restoration induced by budralazine depends on the degree of blood pressure reduction as well as on the duration of the therapeutic period.
我们使用自发性高血压大鼠研究了布屈嗪长期抗高血压治疗对脑血流自动调节下限血压的影响。采用氢清除法测量顶叶皮质和尾状核的脑血流量以确定下限。10只未治疗的自发性高血压大鼠的两个脑区下限均显著高于10只Wistar - Kyoto大鼠。通过高剂量（50 - 68毫克/千克/天）布屈嗪治疗9周，9只大鼠尾状核中上移的下限恢复至接近正常，顶叶皮质部分恢复，治疗期间血压维持在近似正常血压水平；高剂量治疗4周，7只大鼠的两个脑区下限均稍有恢复。然而，低剂量（19 - 27毫克/千克/天）布屈嗪治疗9周使9只大鼠产生中度持续性低血压，并未明显影响下限。我们的结果表明，布屈嗪长期抗高血压治疗可使上移的脑血流自动调节下限血压恢复正常，且布屈嗪诱导的恢复取决于血压降低程度以及治疗期时长。
