Inhibitory mechanism by polysialic acid for lamina-specific branch formation of thalamocortical axons Journal Article
| Authors: | Yamamoto, N.; Inui, K.; Matsuyama, Y.; Harada, A.; Hanamura, K.; Murakami, F.; Ruthazer, E. S.; Rutishauser, U.; Seki, T. |
| Article Title: | Inhibitory mechanism by polysialic acid for lamina-specific branch formation of thalamocortical axons |
| Abstract: | During development, thalamocortical axons form arbors primarily in layer 4 of the neocortex. This lamina-specific branch formation was studied in cultures of rat thalamic explants grown next to chemically fixed cortical slices. After a week in vitro, thalamic axons formed branches specifically in the target layer of fixed cortical slices, regardless of the orientation of the ingrowth. This in vitro system permits a direct assessment of contributions of membrane-associated molecules to thalamic axon branch formation. To this end, the present study uses three enzymatic perturbations: Chondroitinase, phosphatidylinositol phospholipase C, or the polysialic acid (PSA)-specific endoneuraminidase (endo N). With endo N pretreatment of cortex, the number of branch points was increased significantly, whereas branch tip length was decreased. In addition, the localization of branch points to the target layer was weakened considerably. These features of branch formation were not altered by the other two enzymatic treatments, except that branch tips were shortened by chondroitinase treatment to the same extent as in endo N treatment. These results suggest that membrane-bound components are involved in lamina-specific branch formation of thalamocortical axons, and in particular that PSA moieties contribute to laminar specificity by inhibiting branch emergence in inappropriate layers. |
| Keywords: | immunohistochemistry; nonhuman; animals; animal tissue; cells, cultured; microscopy, confocal; basement membrane; cell differentiation; enzyme activity; explant; brain development; polysialic acid; sialidase; rat; neocortex; rats; cerebral cortex; axons; sialic acids; monte carlo method; neural pathways; coculture techniques; degradation; glycoside hydrolases; thalamus; brain slice; nerve fiber growth; axon guidance; nerve sprouting; membrane component; phospholipase c; target recognition; cortical development; priority journal; article; thalamocortical tract; axonal branch; layer specificity; thalamocortical projection; n acetylgalactosamine 4 sulfatase; phosphatidylinositol 4,5 bisphosphate phosphodiesterase; chondroitinases and chondroitin lyases; phosphatidylinositol diacylglycerol-lyase |
| Journal Title: | The Journal of Neuroscience |
| Volume: | 20 |
| Issue: | 24 |
| ISSN: | 0270-6474 |
| Publisher: | Society for Neuroscience |
| Date Published: | 2000-12-15 |
| Start Page: | 9145 |
| End Page: | 9151 |
| Language: | English |
| PUBMED: | 11124992 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Export Date: 18 November 2015 -- Source: Scopus |
