The study of glial cell development and function has been considerably enhanced by the development of methods to culture oligodendrocytes and astrocytes from central nervous system tissue. A primary mixed glial culture, composed mostly of astrocytes, oligodendrocytes, and microglia, is obtained when newborn disaggregated cerebral brain cells from rat are plated at high cell density (2 � 105 /cm2 ) in serum-supplemented medium (McCarthy and de Vellis, 1980 ).
