Richards J G, Schoch P, Häring P, Takacs B, Möhler H
J Neurosci. 1987 Jun;7(6):1866-86. doi: 10.1523/JNEUROSCI.07-06-01866.1987.
Monoclonal antibodies, raised against a purified GABAA/benzodiazepine receptor complex from bovine cerebral cortex, have been used to visualize the cellular and subcellular distribution of receptorlike immunoreactivity in the rat CNS, cat spinal cord, and bovine and postmortem human brain. Two different antibodies have been used for these studies; bd-17 recognizes the beta-subunit (Mr 55 kDa) in all the species tested, whereas bd-24 recognizes the alpha-subunit (Mr 50 kDa) of bovine and human but not rat and cat tissues. In bovine and human brain, both antibodies produced very similar staining patterns, indicating a homogeneous receptor composition, at least in the brain areas investigated. The general distribution and density of receptor antigenic sites in all tissues studied were very similar to that of benzodiazepine binding sites radiolabeled with 3H-Ro 15-1788 and of glutamate decarboxylase (GAD)-stained nerve terminals. The results demonstrate a very high receptor density (around neuronal cell bodies and processes or less discretely distributed) in the rat olfactory bulbs, cerebral cortex, ventral pallidum, islands of Calleja, globus pallidus, hippocampus, dentate gyrus, substantia nigra, geniculate nuclei, inferior colliculus, cerebellum, reticular formation, spinal cord, and retina. In contrast, no receptors could be detected in white matter, pineal, pituitary, adrenals, and superior cervical ganglia. Only among the cerebellar layers did we observe a conspicuous difference between the staining intensity and the radiolabeling. In bovine and postmortem human brain, e.g., hippocampus, dentate gyrus, cerebral cortex, and substantia nigra, the same close correlation between the immunohistochemical and radiohistochemical findings was observed. At the electron microscopic level, the immune reaction product in the rat substantia nigra and globus pallidus, for example, was localized to pre- and postsynaptic membranes of axodendritic and axosomatic synapses. Whether the presynaptic labeling represents GABA autoreceptors is discussed. In the near future, the monoclonal antibodies will be used in double-labeling experiments with GAD to identify those GABAergic projections that are modulated by benzodiazepine minor tranquillizers. Furthermore, they could also be used, in studies of postmortem human brain, to diagnose receptor dysfunction possibly associated with CNS disorders such as epilepsy.
针对从牛大脑皮层纯化得到的GABAA/苯二氮䓬受体复合物产生的单克隆抗体，已被用于观察大鼠中枢神经系统、猫脊髓以及牛和人类尸检大脑中受体样免疫反应性的细胞和亚细胞分布。这些研究使用了两种不同的抗体；bd - 17在所有测试物种中识别β亚基（分子量55 kDa），而bd - 24识别牛和人类组织中的α亚基（分子量50 kDa），但不识别大鼠和猫组织中的α亚基。在牛和人类大脑中，两种抗体产生的染色模式非常相似，表明至少在所研究的脑区中受体组成是均匀的。在所研究的所有组织中，受体抗原位点的总体分布和密度与用3H - Ro 15 - 1788放射性标记的苯二氮䓬结合位点以及谷氨酸脱羧酶（GAD）染色的神经末梢的分布和密度非常相似。结果表明，在大鼠嗅球、大脑皮层、腹侧苍白球、卡耶哈岛、苍白球、海马体、齿状回、黑质、膝状核、下丘、小脑、网状结构、脊髓和视网膜中，受体密度非常高（围绕神经元细胞体和突起或分布较不分散）。相比之下，在白质、松果体、垂体、肾上腺和颈上神经节中未检测到受体。仅在小脑各层中，我们观察到染色强度与放射性标记之间存在明显差异。例如，在牛和人类尸检大脑的海马体、齿状回、大脑皮层和黑质中，免疫组化和放射组化结果之间也观察到相同的紧密相关性。在电子显微镜水平上，例如在大鼠黑质和苍白球中，免疫反应产物定位于轴突 - 树突突触和轴突 - 体突触的突触前膜和突触后膜。讨论了突触前标记是否代表GABA自身受体。在不久的将来，单克隆抗体将用于与GAD的双标记实验，以识别那些受苯二氮䓬类弱安定药调节的GABA能投射。此外，它们还可用于人类尸检大脑的研究中，以诊断可能与癫痫等中枢神经系统疾病相关的受体功能障碍。
