不同程度缺氧对大鼠急性缺氧适应形成的影响

观察不同程度缺氧ＳＤ大鼠（Ａ组：呼吸高峰减弱时刻，Ｂ组：首次端呼吸出现，Ｃ组：末次呼吸出现即缺氧耐受极限出现）的机能状态（呼吸、心率、紫绀）、缺氧耐受时间、大脑皮层电活动（诱发电位、脑电图），并进行急性重复缺氧实验。结果发现，Ａ组大鼠机能状态活跃，大脑皮层电活动逐次加强；Ｂ、Ｃ组大鼠机能状态、大脑皮层电活动逐次抑制，缺氧对Ｃ组大鼠机能状态、大脑皮层电活动的抑制程度比Ｂ组大鼠严重。Ａ组１～４次缺氧耐受时间之间无显著差异，Ｂ、Ｃ组大鼠缺氧耐受时间逐次递增，Ｃ组递增的幅度大于Ｂ组。第２、３、４次缺氧耐受时间Ａ组大鼠分别为第１次缺氧的１．０３、１．０３、１．０５倍；Ｂ组大鼠为１．２０、１．５０、２．１６倍；Ｃ组为１．４３、１．９１、２．７４倍。结果提示：大鼠急性缺氧耐受与中枢抑制有关，缺氧耐受性递增幅度与中枢抑制程度有关。

Effect of Different Degree of Hypoxia on Adaptation to Acute Repetitive Hypoxia

Experiments were conducted on SD rats. Three different limrts of tolerance, point of peak breath failing (group A) ,appearance of first gasping (group B) and last breath (group C) were used as the start of next exposure,respectively. As exposure went on,anmals' state and cortical electrical activity increased in group A while deceased in group B and C. The to lerance time of the second ,third and fourth run was 1. 03, 1. 03, 1. 05 times in group A; 1. 20 ,1. 50 and 2. 16 times in group B;and 1. 43, 1. 91 and 2. 74 times in group C,respectively longer than that of their own first run. These results indicate that adaptation to hypoxia is related to inhibition of the central nervous system and the extent of increase in tolerance seems to be correlated to the extent of inhibition.