CELLULAR AND EXTRACELLULAR COMPONENTS AT NODES OF RANVIER IN RAT WHITE-MATTER

Rat CNS nodes of Ranvier were investigated by electron microscopy and immunohistochemistry. Nodes along thin callosal axons possess tiny nod e gaps containing few or no astrocytic processes. Nodes along thick sp inal axons exhibit spatious node gaps containing relatively few irregu larly arranged astrocytic processes. Antibodies against HNK-1, chondro itin sulfate, tenascin or NSP-4 do not label small nodes but stain lar ge nodes. We conclude that rat CNS fibers do not exhibit a strict rela tion between nodal complexity and fiber size comparable to that found in rat PNS fibers.