NEURONS ARE GENERATED IN CONFLUENT ASTROGLIAL CULTURES OF RAT NEONATAL NEOCORTEX

Cells of the telencephalon are generated in specific proliferative zon es from which neuronal and glial precursors migrate to their destinati ons. Recent evidence indicates that some precursors do not turn into d ifferentiated cells but keep their ability to proliferate. Here, we re port that neurons can originate in primary cultures of astroglial cell s prepared from neocortex of newborn rats. The first neuronal cells ap peared shortly before confluence, when a glial monolayer was being for med. After confluence, these still undifferentiated cells increased in number. Later, they became immunohistochemically positive for the neu ron-specific marker microtubule-associated protein 2a,b. They also con tained neurofilament-l protein as well as the specific messenger RNA c oding for neurofilament-H. The observation that they took up bromo-deo xyuridine indicated that they synthesized DNA, i.e. they proliferated. When Dulbecco's modified essential medium was substituted with fetal calf serum, the appearance of neurons depended on the seeding density of the dispersed cells. This was no longer the case, when the cultures were maintained in Dulbecco's modified essential medium/F12 medium to which transferrin, insulin and selenium chloride had been added. It i s concluded that neuronal precursors can survive in primary astroglial cultures. After confluence of the astroglial cells the precursors pro liferate if appropriate conditions are present. Our observation provid es a new model for the investigation of cultured neurons and neuronal- glial interactions. (C) 1997 IBRO. Published by Elsevier Science Ltd.