Myelination and glial ensheathment of Purkinje cells in cerebellar cultures are not inhibited by antibodies to the neural cell adhesion molecule, N-CAM.

Mouse cerebellar cultures were exposed to anti-N-CAM antibodies throughout their in vitro development. Some cultures were stripped of myelinating oligodendrocytes and functionally competent astrocytes by treatment with cytosine arabinoside (Ara C), while others were left untreated and were potentially capable of forming myelin around axons and astrocytic sheaths around Purkinje cell somata and dendrites. As expected, the antibodies inhibited axonal fasciculation in the Ara C treated cultures. However, the same antibodies had no discernible effect on formation of myelin or astrocytic sheaths in cultures not treated with Ara C. N-CAM is expressed on the surfaces of neurons, oligodendroglia and astrocytes, and has been proposed as the signal molecule governing both kinds of neuron-glia interactions. The observations of the present study strongly suggest, however, that N-CAM does not have an indispensable role in such interactions.