应用PET监测异丙酚与异氟醚对脑内葡萄糖代谢及可能作用的中枢部位的影响

Effects of propofol or isoflurane on cerebral glucose metabolism and the probable functional sites monitored by positron emission tomography

目的:应用正电子发射计算机断层扫描技术(positronemissiontomogra-phy,PET),研究静脉麻醉剂异丙酚和吸入麻醉剂异氟醚对健康自愿者脑内葡萄糖代谢的影响,分析两种麻醉剂在中枢的可能作用部位。方法:选择健康自愿者10名,每一名自愿者按随机顺序分别作3次PET扫描,1次在清醒状态下扫描作为对照,1次在异丙酚(靶控效应室浓度3.0mg/L)麻醉状态下扫描,1次在异氟醚(1.0肺泡气最低有效浓度)麻醉状态下扫描。采用18F-FDG示踪技术测定脑内葡萄糖代谢。结果:①异丙酚麻醉后,与清醒状态比全脑的葡萄糖代谢率(CMGlu)降低34.1%(P<0.05),在丘脑、大脑皮质、小脑和海马等区域葡萄糖代谢率(rCMGlu)明显低于清醒状态(P<0.05),其中丘脑降幅最大达51.5%。②异氟醚麻醉后,与清醒状态比全脑的CMGlu降低37%,以丘脑和扣带回降低更为显著(P<0.05)。结论:异丙酚和异氟醚麻醉后均可使全脑和脑内各区域葡萄糖代谢显著降低,其中异丙酚对丘脑、大脑皮层和海马更为敏感,这些可能是异丙酚在中枢的作用部位;而异氟醚在脑内作用的靶区可能在丘脑、扣带回。

AIM:To investigate the effects of injecting propofol into vein and inhaling isoflurance on regional cerebral glucose metabolism in healthy volunteers and to analyze the possible location acted by propofol and isoflurane in center with the positron emission tomography(PET) technology. METHODS:Ten healthy volunteers were selected for PET scans,each underwent randomly three PET scans: one scan assessed awake baseline metabolism. The secend scan assessed metabolism during propofol(3.0 mg/L).The third scan assessed metabolism during 1.0 minimal alvelolar concentration isoflurane anesthesia.The cerebral glucose metabolism was measured with 18fluorodeoxyglucose 18F HDGtechnique. RESULTS:The whole brain glucose metabolism decreased 34.1%(P< 0.05) compared with staying awake after propofol anesthesia, and the decreasing rate of glucose metabolism in thalamus, cerebral cortex, hippocampus and cerebellum were significantly lower(P< 0.05),and thalamus area had the largest decrease(51.5%).The decreasing rate of the whole brain glucose metabolism was 37%compared with staying awake after isoflurane anesthesia, and thalamus and cingulated gyrus were significantly lower(P< 0.05). CONCLUSION:Whole brain and regional glucose metabolism decreased significantly after propofol or isoflurane anesthesia.Propofol was more sensitive to thalamus,cerebral cortex and hippocampus where are likely to be primary targets in propofol anesthesia.But thalamus and cingulated gyrus are likely to be key targets for isoflurane effects.