Bamford O S, Dawes G S
Dept. of Pediatrics, University of Maryland Hospital, Baltimore 221201.
J Dev Physiol. 1990 May;13(5):271-6.
In order to investigate possible mechanisms for the effect of hypoxia on fetal electrocortical (ECoG) activity, the effects of 30 min of isocapnic hypoxia on ECoG were studied in three groups of unanaesthetized late-gestation fetal lambs in utero. One group was intact, in the second the brainstem was transected between the colliculi, and in the third the carotid sinus nerves and cervical vagosympathetic trunks were cut bilaterally to denervate the systemic arterial chemoreceptors. The incidence of high voltage (HV) ECoG activity was lower in brainstem-transected fetuses than in the other groups. All three groups showed an increased number of changes from low to high voltage and an increase in the incidence of HV activity at the onset of hypoxia, but the increases reached statistical significance only in the brainstem-transected group. It is concluded that the onset of hypoxia is often associated with an increase in HV ECoG activity, with the most consistent changes occurring after brainstem transection and similar but smaller increases in intact and denervated fetuses. Thus the response of fetal electrocortical activity to the onset of hypoxia does not depend on intact connections with the lower brainstem. However, the effect of hypoxia on fetal ECoG is minor and inconsistent and may be physiologically unimportant.
为了探究缺氧对胎儿脑电活动（ECoG）产生影响的可能机制，对三组未麻醉的妊娠晚期子宫内胎羊进行了研究，观察了30分钟等碳酸血症性缺氧对ECoG的影响。一组为完整胎儿，第二组在中脑之间横断脑干，第三组双侧切断颈动脉窦神经和颈迷走交感干以去除全身动脉化学感受器的神经支配。横断脑干的胎儿中高电压（HV）ECoG活动的发生率低于其他组。所有三组在缺氧开始时从低电压到高电压的变化数量均增加，HV活动的发生率也增加，但仅在横断脑干的组中增加达到统计学意义。得出的结论是，缺氧开始通常与HV ECoG活动增加有关，最一致的变化发生在脑干横断后，完整和去神经支配的胎儿中也有类似但较小的增加。因此，胎儿脑电活动对缺氧开始的反应不依赖于与低位脑干的完整连接。然而，缺氧对胎儿ECoG的影响较小且不一致，可能在生理上并不重要。
