Fig. 2.

Time-dependent effects of neurotrophins on synaptic and glutamate responses. A, Synaptic responses in patch-clamped cells after exposure of a nearby neuron to glutamate. Culture of E16-derived neurons exposed to BDNF plus NT-3 (NT) for 24 hr produced a small but clear increase in the proportion of evoked responses, whereas exposure of these cultures for 72 hr produced an effect similar in magnitude to that of a chronic treatment with NT. B, Responses of E16 cells to topical application of glutamate does not differ in control, and in cultures exposed for 1, 2, or 3 d to the neurotrophins.Top, Sample records of the response to the application of glutamate. Bottom, Summary of peak inward current densities generated by exposure to glutamate.