Fig. 2.

Effects of BDNF on hilar-evoked responses of granule cells in slices with or without mossy fiber sprouting.A, In a rat that had mossy fiber sprouting, a hilar stimulus evoked two population spikes in the granule cell layer before BDNF application. The population spike with the shortest latency (arrow) was likely to be antidromic because it immediately followed the stimulus, and the later spike (arrowhead) was likely to be caused by mossy fiber collaterals that activated granule cells, because it was never present in slices without sprouting (see B). The orthodromic population spike increased in amplitude after exposure to BDNF (200 ng/ml, 45 min), and secondary population spikes developed (arrowheads). Stimulus artifacts are marked bydots and are truncated. Calibration: 4 mV, 10 msec.B, In a rat that was treated with pilocarpine but did not have mossy fiber sprouting, a stimulus to the hilus evoked an antidromic spike, and this was unchanged after perfusion with BDNF for 1 hr. Note change in time base compared with A. Calibration (shown in A): 4 mV, 5 msec.C, In the same slice as A, spontaneous bursts of population spikes occurred after BDNF. Voltage calibration shown in A.