Long-term bFGF neuronal culture: reintroduction into serum medium yields neurons and non-neuronal cells with neuronal characteristics

The potential use of bFGF immortalized cells as hosts for delivering foreign genes into nervous tissue led us to examine the effect of maintaining E-18 hippocampal neurons for extended periods in bFGF culture prior to transfer into a standard, serum-containing, medium. We found: (1) many, if not most, precursors seen in bFGF, mature into glia and not into primary neurons after medium exchange; (2) the electrophysiology of the neurons which do mature after medium transfer and replating, is similar to that of neurons in standard cultures; (3) extended culture in bFGF prior to cell harvesting and replating into standard medium generates neurons from the precursors that possess proper neuronal polarization, morphology, and electrophysiology; and (4) extended bFGF also induces the expression, on transfer into standard medium, of an additional cell type with a distinct non-neuronal morphology that stains with the neuronal marker MAP-2. These results illustrate the need for additional characterization of long-term growth factor effects on maintained progenitor cells prior to their use in gene therapy and transplantation. © 1995.