SYNAPTIC EFFICACY ENHANCED BY GLIAL-CELLS IN-VITRO

In the developing nervous system, glial cells guide axons to their tar get areas, but it is unknown whether they help neurons to establish fu nctional synaptic connections, The role of glial cells in synapse form ation and function was studied in cultures of purified neurons from th e rat central nervous system, In glia-free cultures, retinal ganglion cells formed synapses with normal ultrastructure but displayed little spontaneous synaptic activity and high failure rates in evoked synapti c transmission, In cocultures with neuroglia, the frequency and amplit ude of spontaneous postsynaptic currents were potentiated by 70-fold a nd 5-fold, respectively, and fewer transmission failures occurred, Gli al cells increased the action potential-independent guantal release by 12-fold without affecting neuronal survival, Thus, developing neurons in culture form inefficient synapses that require glial signals to be come fully functional.