title: Transient down-regulation and restoration of glycogen synthase levels in axotomized rat facial motoneurons.
abstract: In adult rats, transection of the facial nerve causes a functional down-regulation of motoneurons and glial activation/proliferation. It has not been clear how energy-supplying systems are regulated in an axotomized facial nucleus. Here we investigated the regulation of molecules involved in glycogen degradation/synthesis in axotomized facial nuclei in rats. Immunoblotting revealed that the amounts of glycogen phosphorylase in the contralateral and ipsilateral nuclei were unchanged for the first 14 days, whereas the amount of glycogen synthase in the axotomized facial nuclei was significantly decreased from days 7-14 post-insult. A quantitative analysis estimated that the glycogen synthase levels in the transected nucleus were reduced to approx. 50% at 14 days post-injury. An immunohistochemical study showed that the injured motoneurons had decreased expressions of glycogen synthase proteins. The glycogen synthase levels in the axotomized facial nucleus had returned to control levels by 5 weeks post-insult, as had the cholinergic markers. The immunohistochemical study also revealed the recovery of glycogen synthase levels at the later stage. The glycogen phosphorylase levels in the injured nucleus were not significantly changed during weeks 3-5 post-insult. Taken together, these results demonstrated that the injured facial motoneurons transiently reduced glycogen synthase levels at around 1-2 weeks post-insult, but restored the levels at 4-5 weeks post-insult.
authors.affiliation: Department of Bioinformatics, Faculty of Engineering, Soka University, Tokyo 192-8577, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Takezawa
authors.affiliation: Department of Neurochemistry, National Institute of Neuroscience, Tokyo 187-8502, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kohsaka
authors.affiliation: Department of Bioinformatics, Faculty of Engineering, Soka University, Tokyo 192-8577, Japan. Electronic address: nakajima@t.soka.ac.jp.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Nakajima
mesh_terms: D000818:Animals; D019771:Axotomy; D039481:CD11b Antigen / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002452:Cell Count; D015536:Down-Regulation / Q000502:physiology*; D020220:Facial Nerve Injuries / Q000378:metabolism / Q000473:pathology*; D007839:Functional Laterality; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D024981:Glycogen Phosphorylase / Q000378:metabolism; D006006:Glycogen Synthase / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism; D009046:Motor Neurons / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D020127:Recovery of Function / Q000502:physiology; D013997:Time Factors; D050494:Vesicular Acetylcholine Transport Proteins / Q000378:metabolism
chemical_list: C100745:Aif1 protein, rat; D039481:CD11b Antigen; D002135:Calcium-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D008840:Microfilament Proteins; C501155:NR3B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate; C493461:Slc18a3 protein, rat; D050494:Vesicular Acetylcholine Transport Proteins; D024981:Glycogen Phosphorylase; D006006:Glycogen Synthase
keywords: Facial motoneuron; Glycogen synthase; Regeneration; Transection