Abstract: Objective To provide a systematic map of α-synuclein(α-Syn) localization in the normal rat spinal cord. Methods Two home-made monoclonal antibodies(2E3 and 3D5) against α-Syn were immumohistochemically used to reveal the localization of α-Syn in the spinal cord. Luxol Fast Blue staining was applied to identify the unmyelinated nerve fibres. Double immunofluorescence was used to observe the co-localization of α-Syn with neuropeptide Y(NPY). Results α-Syn was localized in the neuronal nuclei and the unmyelinated nerve fibers within the gray matter. In both 2E3-and 3D5-stained sections, intensely stained nerve fibers were observed in laminae Ⅰ and Ⅱ. However, the immunopositive neuronal nuclei were only found in 3D5-stained sections, which were localized within the gray matter, especially in laminae Ⅶ, Ⅷ, Ⅸ, Ⅹ. Double immunofluorescent staining showed that some of the α-Syn-immunoreactive fibers and terminals in laminae Ⅰ and Ⅱ stained also for neuropeptide Y(NPY) in the dorsal horns, whereas in the anterior horns, a few motor neurons expressing α-Syn in the nuclei had cytoplasmic NPY. Conclusion α-Syn is localized in the neuronal nuclei and the unmayelinated nerve fibers within the gray matter of the spinal cord. Some of the α-Syn-positive neurons and fibers are NPY-positive.

Key words: α-synuclein, spinal cord, neuron, rat