We have shown previously that switching of the ␣v-associated 1 and 5 integrin subunits during differentiation of myelin-forming oligodendrocytes may regulate important aspects of cell behaviour such as migration (Milner et al., 1996: J Neurosci 16:7240-7252). In this study we have examined the developmental regulation of other ␣v-associated  subunits in oligodendroglial cell cultures and also the control of their expression by neurons, using xenocultures to distinguish glial and neuronal integrins. We have found that oligodendroglia express ␣v8 in addition to the previously-described ␣v1, ␣v3, and ␣v5. 8 and 3 together comprise the 80kD band seen in ␣v immunoprecipitations that represents the most abundant ␣v-associated  subunit and show reciprocal patterns of expression during development. ␣v8 is expressed at high levels on oligodendrocyte precursors and differentiated oligodendrocytes but diminishes during the intermediate stages of differentiation. ␣v3, in contrast, shows an opposite pattern of expression, with the highest levels seen at the intermediate stages of differentiation and little expression on either oligodendrocyte precursors and differentiated oligodendrocytes. The expression of ␣v3 is not altered by coculture with neurons, unlike that of ␣v8, in which the decrease seen at the intermediate stages of differentiation is less marked in the presence of neurones. Our results confirm that switching of ␣v-associated  subunits is an important feature of oligodendrocyte differentiation and suggest that ␣v8 and ␣v3 have distinct functions during myelination.