Differentiation of corpus callosum glial cells and factors influencing their maturation in vitro.

1. Explants of Corpus callosum (c. c.) from 12-day-old rats were cultivated under different experimental conditions. 2. Migration and differentiation is activated by the presence of neighbouring explants, toward which glial cells predominantly migrate. Glial cells migrate if closely adhering to the supporting collagen and the process of differentiation is enhanced by presence of underlying cell layers. 3. Migratory activity of glial cells decreases and is delayed with age of donors. Migrating cells have a similar appearance as in cultures from 12 days old donors. The presence of immature types of glial cells in c. c. of adult animals was proved. 4. Glucose was found to be an adequate metabolical substrate, utilisation of glucose being lower than in cultivated neurons. In the absence of glucose or serum in the medium, neither migration nor differentiation of glial cells was observed. 5. The addition of embryonal extract and embryonic brain extract enhanced only initial stages of cell migration and differentiation.