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Enzymological and immunohistochemical study of enzyme system which participates in the narcotic and/or psychostimulant netabolism in human brain

参与人脑麻醉和/或精神兴奋剂代谢的酶系统的酶学和免疫组织化学研究

基本信息

批准号：
08670485
负责人：
YAMAZAKI Motohiro
金额：
$ 1.47万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

The flavin-containing monooxygenase (FMO) is widely distributed in mammalian organs and catalyzes N-oxidation of secondary and tertiary amines (including methamphetamine and cocaine) and S-oxidation of thiols and thiourea. We paid attention to the enzyme, and examined enzymologically and immunohistochemically. Postmortem changes of FMO activities in the autolyzing liver of rat cadavers were studied to assess the stability of the drug-metabolizing enzymes. The activity of FMO was measured by methimazole (MEM : for S-oxidation) and trimethylamine (TMA : for N-oxidation) as substrates. Both MEM and TMA activities of FMO were formed to be gradually activated and maximum activation occurred at 6 h postmortem. After that, the activities of the enzyme were declined similarly and rapidly. The distribution of activities of FMO in human brains were studied in forensic autopsy cases. The MEM activities of FMO showed marked regional variation ; the highest activity was observed in the brain cortex, followed by the thalamus, cerebellum, striatum, cerebral medulla, pons and medulla oblongata. Immunohistochemical examination of human liver sections using an antibody produced against pig liver FMO demonstrated that FMO was non-uniformly distributed across the human liver acinus ; all hepatocytes were stained positively for FMO, with the intensity being highest in zone 3. Immunocytochemical examination of human kidney sections demonstrated localization of the enzyme in the proximal and distal convoluted tubules of the renal cortex, but not the glomeruli. These observations may lead to bette understanding of mechanism of site-specific drug toxicity. The last, we discussed forensic toxicologically about autopsy cases of poisoning by neuropsychopharmaceuticals.

含黄素单加氧酶（FMO）广泛分布于哺乳动物器官中，催化仲胺和叔胺（包括甲基苯丙胺和可卡因）的N-氧化以及硫醇和硫脲的S-氧化。我们关注了该酶，并进行了酶学和免疫组织化学检查。研究了死后大鼠尸体自溶肝脏中 FMO 活性的变化，以评估药物代谢酶的稳定性。 FMO 的活性通过甲硫咪唑（MEM：用于 S-氧化）和三甲胺（TMA：用于 N-氧化）作为底物进行测量。 FMO的MEM和TMA活性逐渐激活，最大激活发生在死后6小时。此后，酶的活性同样迅速下降。在法医尸检案例中研究了 FMO 在人脑中的活性分布。 FMO的MEM活动表现出明显的地区差异；大脑皮层的活动最高，其次是丘脑、小脑、纹状体、大脑延髓、脑桥和延髓。使用抗猪肝 FMO 的抗体对人肝切片进行免疫组织化学检查，结果表明 FMO 在人肝腺泡上分布不均匀；所有肝细胞均呈 FMO 染色阳性，区域 3 的强度最高。人肾切片的免疫细胞化学检查表明该酶定位于肾皮质的近曲小管和远端曲管，而不是肾小球。这些观察结果可能有助于更好地理解位点特异性药物毒性的机制。最后，我们从法医毒理学角度讨论了神经精神药物中毒尸检案例。