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Fig. 6
Myelin P0 expression in the hindbrain, cranial nerves, and spinal cord. Transverse sections of adult zebrafish hindbrain and spinal cord were labeled by immunohistochemistry to reveal P0 (A,C,E–L), or by immunofluorescence to detect P0 (red), Zebrin II (green) and nuclei (blue) (B,D). The bar in A shows the scale for A,E–I; the bar in C shows the scale for C,J; the bar in K shows the scale for K,L. A: Body of cerebellum. Black arrows indicate bundles of P0-immunoreactive fibers that appear to arise from the junction between the molecular and granule cell layers. White arrows indicate P0-expressing fibers that pass through the granular eminence. B: A single confocal plane is shown at the junction between the molecular and granule cell layers to illustrate the relationship between P0 immunoreactive fibers (red, red arrows) and Purkinje cells and their axons (green, green arrows). Nuclei of the granule cell layer (blue) are seen at the bottom of the image. C: Body of cerebellum. The neuropil of the molecular layer is shown. Black arrows show examples of the numerous single P0-immunoreactive fibers passing through the molecular layer. D: A single confocal plane of the molecular layer is shown to illustrate the relationship between P0 immunoreactive fibers (red) and Purkinje cell dendrites (green). E: Dorsal medulla. F: Ventral medulla. G: Cranial nerve VIII. H: Cranial nerve X. I–L: Spinal cord. Images K,L show adjacent sections that were labeled identically, except that the section shown in panel L was pretreated to remove myelin lipids before processing for immunohistochemistry. The black arrows show the regions in Fld and Fv that show enhanced P0 immunoreactivity following lipid solubilization.