FOREBRAIN AND MIDBRAIN ASTROCYTES PROMOTE NEURITOGENESIS IN CULTURED CHROMAFFIN CELLS

Adrenal chromaffin cells from immature or adult rats were grown in one of the following 'in vitro' conditions: (1) on coverslips placed on t op of confluent, fetal, regional glia cultures; (2) in conditioned med ia from similar confluent cultures; (3) after direct seeding on top of such confluent cultures. Astroglia was obtained from cerebral cortex, septum, striatum and ventral mesencephalon from E16-17 pregnant-dated rats. All regions successfully generated conditions for the early (le ss than 24 h) expression of neuritogenesis in about 15% of cells, whic h was more apparent in immature adrenal cell dissociates than in adult ones. The former grew long neurites compared with their adult counter parts. In addition to the known effects of glioma conditioned medium a nd isolated trophic factors described by other authors, it is conclude d that adrenal chromaffin cells are responsive to the neuritogenic act ivity of (central) astroglial diffusible factor(s) in non-supplemented , defined culture media conditioned by astrocytes from various brain r egions. Additionally, evidence is offered that adult chromaffin cells show a reduced responsiveness towards such astroglial factor(s). Possi ble implications for cell transplantation chimeras are discussed.