Black K L, Ikezaki K, Toga A W
Division of Neurosurgery, University of California School of Medicine, Los Angeles.
J Neurosurg. 1989 Jul;71(1):113-8. doi: 10.3171/jns.1989.71.1.0113.
Peripheral benzodiazepine receptor ligands were utilized to selectively image intracerebrally implanted C6 gliomas, RG-2 gliomas, and Walker 256 metastatic tumors by means of quantitative autoradiography. Intravenous injections of 3H-PK11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide) or 3H-flunitrazepam in combination with clonazepam revealed high densities of peripheral benzodiazepine binding in glial tumors, with less binding in metastatic tumors. Peripheral binding was displaced by preadministration of excess PK11195. Topographical correlation was excellent between areas of histologically verified tumor and high densities of peripheral benzodiazepine binding. The choroid plexus, ependyma, and pineal gland also showed a moderate level of binding, but there was little binding in other normal brain structures or necrotic tissue. Binding densities were three- to fivefold higher in C6 glial tumors compared to normal cortex. Injection of 3H-flunitrazepam alone, which binds to both central and peripheral receptors, had the advantage of showing normal anatomic structures in addition to a clear definition of tumor topography. The potential value of peripheral benzodiazepine ligands in selectively imaging brain tumors in man with positron emission tomography is discussed.
利用外周苯二氮䓬受体配体，通过定量放射自显影术对脑内植入的C6胶质瘤、RG - 2胶质瘤和Walker 256转移瘤进行选择性成像。静脉注射3H - PK11195（1 - (2 - 氯苯基)-N - 甲基 - N - (1 - 甲基丙基)-3 - 异喹啉甲酰胺）或3H - 氟硝西泮联合氯硝西泮显示，胶质细胞瘤中外周苯二氮䓬结合密度高，转移瘤中结合较少。预先给予过量的PK11195可使外周结合被取代。经组织学证实的肿瘤区域与外周苯二氮䓬结合高密度区域之间的地形相关性极佳。脉络丛、室管膜和松果体也显示出中等水平的结合，但在其他正常脑结构或坏死组织中结合很少。与正常皮质相比，C6胶质细胞瘤中的结合密度高3至5倍。单独注射3H - 氟硝西泮，其可与中枢和外周受体结合，除了能清晰界定肿瘤地形外，还具有显示正常解剖结构的优势。文中讨论了外周苯二氮䓬配体在利用正电子发射断层扫描对人脑肿瘤进行选择性成像中的潜在价值。
