EXPRESSION OF THE LARGE MYELIN-ASSOCIATED GLYCOPROTEIN ISOFORM IN RAT OLIGODENDROCYTES AROUND CEREBRAL INFARCTS

An immunohistochemical method that uses two specific anti-sera-distinguishable myelin-associated glycoprotein (MAG) isoforms showed an expression of large MAG isoform (L-MAG) protein in the oligodendrocyte cytoplasms in the white matter around experimental cerebral infarcts produced by occlusion of the left middle cerebral artery in the rat. L-MAG protein also was detected in the white matter on the contralateral side. This protein appears prior to S-MAG protein in myelination and remyelination in the central and peripheral nervous systems, and is believed to function in myelin formation. Because L-MAG protein has been found in the oligodendrocyte cytoplasm only in the early development period, its appearance in this cytoplasm after ischemic insult is evidence of MAG regeneration.