氧在低氧适应家兔脑血流调节中的作用

33只大耳白兔随机分成适应组和对照组,适应组适应结束后与对照组一起急性暴露于不同浓度的低氧混合气下,观察氧在低氧适应家兔CBF 调节中的作用.结果显示,急性缺氧时,适应组CBF 明显低于对照组,使用CSF-N_2时,适应组脑表面微血管扩张程度小于对照组。适应组Pao_2、Pvo_2 PHa、PHv、Sao_2、Hb 和CSFP 高于或明显高于对照组;Paco_2、Pvco_2和BP 与对照组相似。提示氧在低氧适应家兔CBF 调节中的作用,可能是通过低氧适应的脑血管和CBF 对低氧的反应降低、脑组织Po_2升高、脑细胞外液H~+]减少,CSFP 和Hb 增加等因素而导致CBF减少。

Effects of Oxygen on Regulation of Cerebral Blood Flow in the Rabbits Adapted to Hypoxia

33 rabbits were randomly divided into adapted and control groupsto investigate the effects of oxygen on regulation of cerebral bloodflow(CBF) in the rabbits adapted to hypoyia using electromagneticflowmeter under acute exposure to various oxygen levels of air.The results showed:(1)responses of cerebral vessels and CBF.tohypoxia did not alter significantly in the adapted group but signifi-cantly exaggerated in the control group;(2)During perfusing thespace under the cranial window with artificial cerebrospinal fluidequilibrated with 100% No,diameter of microvessels on cerebralsurface did not change significantly in the adapted group but sign-ificantly increased in the control group;(3)PaO_2,PvO_2 in brain,arterial Oxygen saturation,cerebrospinal fluid pressure (CSFP) werehigher in the adapted group than in the control group;and(4)arterio-venous difference of oxygen in brain,BP,PaCO_2,and PvCO_2in brain were similar in the two groups.