Fig. 2.

BDNF enhances the activity of glutamatergic neurons in the fetal preBötC network. Intracellular recordings (top traces) from a rhythmic preBötC neuron in current-clamp (A) and voltage-clamp (B) mode recorded simultaneously with integrated population activity (bottom traces) under control conditions. The ellipse in B indicates the period between inspiratory bursts, represented at an extended time scale for a different neuron in C. Note that the application of CNQX blocks all excitatory glutamatergic events (right panel in C). The rectangle in B highlights one inspiratory burst, represented at an extended time scale in (D). Current traces recorded between inspiratory bursts at a holding potential of −50 mV are shown in control (E) and in the presence of BDNF (F). The four traces illustrated correspond to four samples obtained from the same neuron before and after BDNF application. White triangles indicate outward chloride-mediated synaptic currents and black triangles indicate inward glutamate-mediated synaptic currents. (G) Graph representing the mean number of inhibitory (IPSCs) and excitatory (EPSCs) events/s obtained from seven neurons in control conditions (light grey and white bars, respectively) and after BDNF treatment (dark grey and black bars, respectively). Synaptic glutamatergic drive (single event in H and average of 10 events in I) recorded from a fetal rhythmic neuron during a burst of population activity in control conditions (left panels in H and I) and after 15 min exposure to 100 ng/mL BDNF (right panels in H and I). Dashed lines indicating amplitude of the mean in the two conditions illustrate the potentiation of synaptic drive observed in the presence of BDNF. (J) Graph depicting the mean amplitude of the synaptic envelope obtained from eight neurons in control conditions (white bar) and after BDNF treatment (black bar). Int, integrated; nb, number; Vm, voltage. *P < 0.05.