Henderson J L, Reynolds J D, Dexter F, Atkins B, Hrdy J, Poduska D, Penning D H
Department of Obstetrics and Gynecology, University of Iowa, College of Medicine, Iowa City, USA.
Brain Res Dev Brain Res. 1998 Feb 10;105(2):287-93. doi: 10.1016/s0165-3806(97)00192-2.
Fetal hypoxia is an important cause of neurologic morbidity and mortality. Hypoxia-induced increase in extracellular glutamate concentration can lead to excitotoxic neuronal death in adults. The objective of this study was to test whether chronic fetal hypoxemia increases extracellular glutamate concentration in the unanesthetized intact cerebral cortex of the near-term fetal sheep. Microdialysis probes were implanted into the parasagittal parietal cortex and periventricular white matter of near-term fetal sheep. At 124 +/- 1 days of gestation, extracellular glutamate concentration was determined before and during 24 h of fetal hypoxemia. Chronic hypoxemia was produced by tightening a vascular occluder placed around the maternal common iliac artery. Larger decreases in fetal arterial oxygen content were associated with larger increases in extracellular glutamate concentration in the parietal cortex (Kendall's tau = 0.81, N = 7, p = 0.005). No such relationship was detected in the periventricular white matter. Chronic hypoxemia increases extracellular glutamate concentration in the intact cerebral cortex of the unanesthetized near-term fetal sheep.
胎儿缺氧是神经疾病发病率和死亡率的一个重要原因。缺氧导致细胞外谷氨酸浓度升高可致使成年动物发生兴奋性毒性神经元死亡。本研究的目的是检测慢性胎儿低氧血症是否会增加近足月胎儿绵羊未麻醉完整大脑皮层中的细胞外谷氨酸浓度。将微透析探针植入近足月胎儿绵羊矢状旁顶叶皮层和脑室周围白质。在妊娠124±1天时，在胎儿低氧血症24小时之前和期间测定细胞外谷氨酸浓度。通过收紧置于母体双侧髂总动脉周围的血管封堵器来产生慢性低氧血症。胎儿动脉血氧含量的较大降低与顶叶皮层细胞外谷氨酸浓度的较大升高相关（肯德尔等级相关系数=0.81，N=7，p=0.005）。在脑室周围白质中未检测到这种关系。慢性低氧血症会增加未麻醉近足月胎儿绵羊完整大脑皮层中的细胞外谷氨酸浓度。
