Figure 4

CD88 is located on presynaptic terminals of the stratum lucidum. A) Low power photomicrograph of nickel-DAB visualized CD88 immunolabelling in the stratum lucidum (St. Luc.) of the rat hippocampus. Ultrathin sections from labelled stratum lucidum and the underlying pyramidal cell layer (Pyr) were further processed for electron microscopy. B) Electron micrograph taken through the pyramidal cell layer of the CA3 region. No nickel deposits were seen on pyramidal cells (P). C) Electron micrograph taken from unlabelled ultrathin sections from the stratum lucidum. Note the presence of unlabelled, large presynaptic terminals (te) in the stratum lucidum. D-H) Electron micrographs demonstrating nickel-DAB intensified labelling for CD88 localized to presynaptic terminals of the rat stratum lucidum. D-F) Presynaptic terminals immunolabelled for CD88 (arrows) were located in close apposition to a dendritic process (d). G-H) Higher magnification electron micrographs of CD88 immunolabelled presynaptic terminals demonstrating their close apposition to postsynaptic densities (arrow head). Scale bars = A, 100 μm; B, 10 μm; C-H, 500 nm.