Up-regulation of polysialic acid in peripheral myelinated axons of rat chronically exposed to 2,5-hexanedione.
Myelinated nerve fibres isolated from Wistar rats chronically exposed to 2,5-hexanedione (0.8 ml/kg/day, intraperitoneally) over a period of 20 days, were stained with lectin-horseradish peroxidase conjugates. The lectins with high affinity for terminal D-galactopyranosyl residues, Bandeiraea simplicifolia-B4 (BSA I-B4) and peanut agglutinin (PNA), showed glycoconjugates in the control nodes of Ranvier. In the treated animals, application of PNA-HRP caused weak reactivity to the node of Ranvier; digestion with sialidase prior to the application of PNA-HRP conjugate enhanced reactivity, thus revealing the presence of a sialoglycoprotein. The results indicate that glycoconjugates of the Ranvier node undergo a rearrangement during exposure to 2,5-hexanedione. In particular, neutral glycoproteins with terminal galactose are replaced by sialoglycoproteins. These findings are consistent with the proposed role of polysialic acid as a regulator of axonal behaviour during regeneration.
Institutes of Pharmacology, University of Bari, Italy.
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D000818:Animals; D001369:Axons / Q000378:metabolism*; D006588:Hexanones / Q000633:toxicity*; D006651:Histocytochemistry; D006735:Horseradish Peroxidase; D037102:Lectins / Q000378:metabolism; D008297:Male; D009186:Myelin Sheath / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism; D011901:Ranvier's Nodes / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000187:drug effects; D012794:Sialic Acids / Q000378:metabolism*; D015854:Up-Regulation
D006588:Hexanones; D037102:Lectins; D011134:Polysaccharides; D012794:Sialic Acids; C021319:polysialic acid; C011269:2,5-hexanedione; D006735:Horseradish Peroxidase