ENERGY METABOLISM

本研究部分的总体目标是调查 围产期脑损伤的高能生化机制 缺氧缺血与如何预防或减少脑损伤 通过特定的治疗方式。具体目标包括：1) 确定高海拔地区变化程度之间的关系 缺氧缺血时能量代谢产物(ATP、PCR)与神经病理的关系 结果；2)确定是否有特异性治疗 已知的最终保存高能代谢物的操作 持续预防或减少缺氧缺血性脑损伤；3) 改进核磁共振测量的空间定位，以更准确地 反映高能量代谢在离散区的变化 未成熟脑；4)探讨镁离子的空间依赖性。 许多必需的酶调节中的重要辅助因子 反应，包括神经传递。以产生围产期缺氧- 缺血性脑损伤，7日龄大鼠将接受单侧 颈总动脉结扎后8%氧气低氧 摄氏37度长达3小时；已知的侮辱会产生选择性 大多数动物的神经细胞坏死或梗塞。在或期间 在缺氧缺血后，动物将接受这些程序 有必要获得连续的31P和1H核磁共振谱，这将允许 对于高能变化的半定量测量 由于侮辱而产生的磷酸盐储备和乳酸。跟随 缺氧-缺血，幼鼠将与其母鼠一起饲养直到 出生后30天，他们将接受灌流- 对他们的大脑进行固定以进行神经病理分析和评分 脑部受损。额外的实验将包括温和的效果 体温过低(34或31摄氏度)或禁食保存高... 缺氧缺血期间和之后的能量磷酸盐储备。 实验还将包括经历缺氧缺血的未成熟大鼠 已注射别嘌醇(100或200md/g/kg)、M-801(0.5- 10 mg/kg)，尼莫地平1-2 mg/kg)，或硫酸镁(0.3-0.6 mg/kg)皮下注射； 接受脑缺氧缺血治疗的未经治疗的窝仔将作为 控制。分析程序将包括顺序测量。 用31P和1H核磁共振波谱以及脑组织分析 高能磷酸盐储备(磷酸肌酸、ATP、ADP、AMP)和 使用高压液相色谱或酶促乳酸盐， 荧光测定法。最后，将开发一种技术来允许 未成熟核磁共振信号在特定区域内的空间定位 老鼠的大脑。

The overall objective of this research component is to investigate the high energy biochemical mechanisms whereby the perinatal brain is damaged by hypoxia-ischemia and how brain injury can be prevented or reduced through specific modalities of therapy. Specific aims include: 1) to ascertain the relationship between the extent of alterations in high energy metabolites (ATP,PCr) during hypoxia-ischemia and neuropathologic outcome; 2) to determine whether or not specific therapeutic manipulations known to preserve high energy metabolites ultimately and consistently prevent or reduce hypoxic-ischemic brain damage; 3) to improve the spatial localization of NMR measurements to more accurately reflect the changes of high energy metabolism in discrete region of the immature brain; 4) to explore the spatial dependence of Mg++, an important co-factor in the regulation of many essential enzymatic reactions, including neurotransmission. To produce perinatal hypoxic- ischemic brain damage, 7-day postnatal rats will undergo unilateral common carotid artery ligation followed by hypoxia with 8% oxygen at 37degreesC for up to 3 hours; an insult known to produce selective neuronal necrosis or infarction in the majority of animals. During or following hypoxia-ischemic, the animals will undergo those procedures necessary to obtain sequential 31P and 1H NMR spectra which will allow for a semi-quantitative measure of the alterations in high-energy phosphate reserves and lactate which result from the insult. Following hypoxia-ischemia, the immature rats will be reared with their dams until 30 days of postnatal age at which time they will undergo perfusion- fixation of their brains for neuropathologic analysis and scoring of brain damage. Additional experiments will include the effect of mild hypothermia (34 or 31degreesC) or of fasting on the preservation of high- energy phosphate reserves during and following hypoxia-ischemia. Experiments also will include immature rats undergoing hypoxia-ischemia which have received either allopurinol (100 or 200 md\g/kg), M-801 (0.5- 10 mg/kg), nimodipine )1-2 mg/kg), or MgS04 (0.3-0.6 mg/kg) s.c.; untreated littermates undergoing cerebral hypoxia-ischemia will serve as controls. Analytical procedures will include sequential measurements with 31P and 1H NMR spectroscopy as well as brain tissue analysis of high-energy phosphate reserves (phosphocreatine, ATP, ADP, AMP) and lactate using high pressure liquid chromatography or enzymatic, fluorometric methods. Finally, a technique will be developed to allow spatial localization of NMR signals within specific regions of immature rat brain.