Huang C C, Yonetani M, Lajevardi N, Delivoria-Papadopoulos M, Wilson D F, Pastuszko A
Department of Biochemistry and Biophysics, Medical School, University of Pennsylvania, Philadelphia 19104.
J Neurochem. 1995 Jan;64(1):292-8. doi: 10.1046/j.1471-4159.1995.64010292.x.
The present study tests the hypothesis that ventilation with 100% O2 during recovery from asphyxia leads to greater disturbance in brain function, as measured by dopamine metabolism, than does ventilation with 21% oxygen. This hypothesis was tested using mechanically ventilated, anesthetized newborn piglets as an animal model. Cortical oxygen pressure was measured by the oxygen-dependent quenching of phosphorescence, striatal blood flow by laser Doppler, and the extra-cellular levels of dopamine and its metabolites by in vivo microdialysis. After establishment of a baseline, both the fraction of inspired oxygen (FiO2) and the ventilator rate were reduced in a stepwise fashion every 20 min over a 1-h period. For the subsequent 2-h recovery, the animals were randomized to breathing 21 or 100% oxygen. It was observed that during asphyxia cortical oxygen pressure decreased from 36 to 7 torr, extracellular dopamine increased 8,300%, and dihydroxyphenylacetic acid and homovanillic acid decreased by 65 and 60%, respectively, compared with controls. During reoxygenation after asphyxia, cortical oxygen pressure was significantly higher in the piglets ventilated with 100% oxygen than in those ventilated with 21% oxygen (19 vs. 11 torr). During the first hour of reoxygenation, extracellular dopamine levels decreased to approximately 200% of control in the 21% oxygen group, whereas these levels were still much higher in the 100% oxygen group (approximately 500% of control). After approximately 2 h of reoxygenation, there was a secondary increase in extracellular dopamine to approximately 750 and approximately 3,000% of baseline for the animals ventilated with 21 and 100%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
与用21%氧气通气相比，窒息复苏过程中用100%氧气通气会导致脑功能出现更大紊乱，这通过多巴胺代谢来衡量。使用机械通气、麻醉的新生仔猪作为动物模型对该假设进行了检验。通过磷光的氧依赖性猝灭来测量皮质氧分压，通过激光多普勒测量纹状体血流量，通过体内微透析测量多巴胺及其代谢物的细胞外水平。在建立基线后，在1小时内每隔20分钟逐步降低吸入氧分数（FiO2）和通气频率。在随后2小时的复苏过程中，将动物随机分为呼吸21%或100%氧气两组。观察到，与对照组相比，窒息期间皮质氧分压从36降至7托，细胞外多巴胺增加8300%，二羟基苯乙酸和高香草酸分别下降65%和60%。窒息后复氧期间，用100%氧气通气的仔猪皮质氧分压显著高于用21%氧气通气的仔猪（分别为19托和11托）。在复氧的第一个小时内，21%氧气组的细胞外多巴胺水平降至对照组的约200%，而在100%氧气组中这些水平仍高得多（约为对照组的500%）。复氧约2小时后，细胞外多巴胺出现二次升高，用21%和100%氧气通气的动物分别升至基线的约750%和约3000%。（摘要截短至250字）
