Age-dependent requirements of sympathetic neurons in serum-free culture

Neurons dissociated from chick sympathetic ganglia of different embryonic ages can be cultured equally well in serum containing or serum-free (N1) medium on collagen polyornithine, and polyornithine pretreated with neurite-promoting factor (PNPF), in the presence of nerve growth factor (NGF). Quantitative analysis of nerve cell survival is best achieved in serum-free conditions and on PNPF-pretreated polyornithine. Under such conditions, 11-day embryonic (E11) sympathetic neurons showed a specific requirement for insulin, selenium and transferrin. Similar analyses at E8 and E16 revealed that the requirement for transferrin is developmentally regulated since it is not expressed by E8 nerve cells until after 3 days in vitro. These data strongly suggest that, besides NGF, other specific molecules are involved in the control of neuronal survival and that specific requirements may be displayed at different embryonic stages.