低氧低二氧化碳对大鼠脑血流的调节作用

低氧下脑血流与急性高原病有关，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，以保护脑血流维持在

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

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.