Unusual morphological changes in cultured oligodendrocytes induced by cytochalasin B.

When cultured chick oligodendrocytes were treated with more than 1 microM of cytochalasin B (CB), an unusual effect, namely the extension of curly processes, was observed in a dose-dependent manner within 2 h after CB was added, that is, the processes with long, thin and curled shapes developed. The effect was found to be reversible and to be inhibited by colchicine. It was demonstrated by immunofluorescence that CB induced the depolymerization of actin filaments and the enhanced assembly of microtubules in cellular processes.