Immuno-electronmicroscopic visualization of cell adhesion molecule L1 in adult rat pyramidal tract: localization on neuronal and oligodendrocytic processes.
The immuno-electronmicroscopic localization of cell adhesion molecule L1 is investigated in adult rat pyramidal tract (PT) at the fifth/sixth cervical spinal cord segment, both by pre-embedding on vibratome sections and by immunogold-labelling on ultra-cryosections. L1-immunoreactivity (L1-IR) can be noted not only on the surface of unmyelinated PT axons, the outer axonal membrane, but also within the axoplasm of myelinated PT axons as well as periaxonally between axolemma and compact myelin. Compact myelin is L1-negative. Interestingly, L1-IR is found in between the inner oligodendrocytic mesaxon and compact myelin. Hence, L1 is expressed by this type of glial cell in adult rat PT. In conclusion, L1 is suggested to be important in the adult rat PT, not only with respect to the adhesion between unmyelinated PT axons but also during stabilization of the mature neuron-oligodendrocyte interaction.
Joosten
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EA
Department of Anatomy and Embryology, Faculty of Medicine, University of Nijmegen, The Netherlands.
D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D009434:Neural Pathways / Q000166:cytology; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure*; D009836:Oligodendroglia / Q000378:metabolism / Q000648:ultrastructure*; D011712:Pyramidal Tracts / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains; D013194:Staining and Labeling
D015816:Cell Adhesion Molecules, Neuronal