Immunocytochemical method to identify basic protein in myelin-forming oligodendrocytes of newborn rat C.N.S.

An immunocytochemical method for detecting myelin basic protein in oligodendrocytes and myelin of newborn rat C.N.S. is described. C.N.S. tissue is perfused and fixes in HgCl2--formaldehyde and 20 micron Vibratome sections are treated with antibodies to myelin basic protein using the peroxidase--antiperoxidase method. Oligodendrocytes in the newborn rat are intensely stained by antiserum to basic protein and multiple stained processes extend from the perikaryon to myelin sheaths. With this procedure it is possible to demonstrate the geometric relationships between a single oligodendrocyte and multiple myelin sheaths. Stained oligodendrocytes and myelin are present in newborn cervical spinal cord, medulla oblongata, pons and midbrain. By 25 days of age, staining in oligodendrocytes is less intense than in newborn rats and differences in amount of staining can be detected in areas that are myelinating at different rates. With anticerebroside serum, cerebroside, of newborn and developing rat C.N.S. tissue is localized only in myelin. In the developing P.N.S., myelin basic protein is localized in Schwann cell cytoplasm and myelin sheaths of the trigeminal ganglion. Cerebroside is found only in myelin.