Astrocyte-regulated synaptogenesis: an in vitro ultrastructural study.

Striatal neurons from E15 rat embryos were dissociated, plated at low cell density on polyornithine or on astrocyte monolayers derived from the striatum (homotopic) or mesencephalon (heterotopic), and cultured in a chemically defined medium. Dendrites developing in homotopic co-cultures could reach a state of maturation allowing the establishment of synapses with axons from mesencephalic explants. This culture system thus partially reproduces the in vivo conditions in which striatal neurons developing in an homotopic glial environment can serve as synaptic targets for afferent mesencephalic axons.