低氧低二氧化碳对大鼠脑血流的调节作用  

REGULATIVE ROLE OF HYPOCAPNIA ON CEREBRAL BLOOD FLOW UNDER HYPOXIA IN RATS

作　　者：顾正中[1] 钟凯声[1] 吕敏[1] 

机构地区：[1]中国科学院上海生理研究所

出　　处：《生理学报》1994年第3期273-280,共8页Acta Physiologica Sinica

基　　金：上海生理研究所低氧生理开放实验室资助

摘　　要：低氧下脑血流（ＣＢＦ）与急性高原病有关，许多研究已证明，低氧不适应者的ＣＢＦ明显高于低氧适应者，而高原世居者则低于海平正常值。低氧下低动脉血二氧化碳分压（ＰａＣＯ２）有对抗低氧扩血管及降低ＣＢＦ的作用。因此研究低氧下低ＰａＣＯ２对ＣＢＦ的调节作用对于研究急性高原病的防治及其机理分析具有重要意义。本项研究目的：（１）揭示低氧下低ＰａＣＯ２与ＣＢＦ之间的关系；（２）通过增加通气量使ＰａＣＯ２下降至合适水平，以保证脑血流维持在低氧适应者水平；（３）观察低氧下低ＰａＣＯ２５ｈ中ＣＢＦ变化情况；（４）离体脑血管对低氧低ＰＣＯ２的反应性及内皮细胞在其中的作用。实验在雄性ＳＤ大鼠尿酯麻醉和三碘季铵酚肌松作用的人工呼吸条件下进行。吸入含有１１．９％氧－８９．１％氮混合气，通过改变通气量来控制ＰａＣＯ２。实验过程中监测血气。用低浓度３％Ｈ２清除法测量ＣＢＦ。实验结果表明：（１）低氧下低ＰａＣＯ２与ＣＢＦ呈良好的相关性，其相关曲线比常氧下ＰａＣＯ２与ＣＢＦ相关曲线更陡；（２）低氧下当通气量控制在常氧对照值的１２５．５％，ＰａＣＯ２下降至常氧对照时的２／３左右，其ＣＢＦ与常氧对照时的水平相近；（３）当ＰａＣＯ２控制在常氧对照值的?The experiments were performed on urethane anesthetized and artificially ventilated SD rats using agascous mixture of 11.9% O2 and 88.1% N2.The PaCO2 wasregulated by changing the volume of ventilation. The items to be studies are:(1)Thecorrelation between hypocapnia and CBF under hypoxia;(2)the value of PaCO2 thatcan keep CBF at the level of hypoxic adapters;(3) the CBF change during a 5 h hypoxia-hypocapnia and(4)the reactivity of isolated basilar artery strips on hypoxiahypocapnia. The results showed:(1) There was a significant correlation between thedegree of hypocapnia and CBF under hypoxia. The correlation curve was steeper thanthat of normoxia.(2) When the ventilation was controled at 25. 5 % above normoxiccontrol value and the PaCO2 was about 2/3of normoxic level under hypoxia, the CBFis near to the level of normoxic control.(3)When the PaCO2 was controled at 2/3 of normoxic level,the CBF could still keep at the level of normoxic control for 5 h.(4)The tension of artery strip was decrease under hypoxia-normocapnia but increased under hypoxia-hypocapnia.Artery stripes with or without endotheliocyte make no difference in their tension changes due to changes of O2-CO2 tension.

关 键 词：脑血流 低氧 低二氧化碳 高山病 

分 类 号：R594.302[医药卫生—内科学]