[The distribution of actin on cultured oligodendrocytes from rat optic nerve]

Two types of cultured oligodendrocytes (OLs) from rat optic nerve were analyzed for the distribution of actin, a major contractile protein, using immunocytochemistry. Type 1 OLs showed extensive network of processes and type 2 OLs showed elaborate membranous expansion along an extensive network. Actin was diffusely stained on an extensive network of processes in type 1 OLs and on the distal portion of membranous expansion in type 2 OLs, but some oligodendrocytes were not stained. It was demonstrated that the distribution of actin in type 1 OLs and type 2 OLs varied with development in oligodendrocyte differentiation and maturation. Our results suggest that undifferentiated and immature oligodendrocytes display remarkable cell movement to search for target axons, and differentiated and mature oligodendrocytes do not require cell movement when myelination has finished. In conclusion, it is considered that actin plays an important role in myelinogenesis.