Developmental changes in the BDNF mediated modulation of spontaneous and evoked postsynaptic currents (sPSCs, ePSCs) in the pontine Kölliker‐Fuse nucleus (KF) of rat

The KF undergoes a substantial postnatal maturation process that might influence the plasticity of the respiratory network in response to sensory inputs (Dutschmann et al. 2004). However, it remains unclear what kind of cellular processes influence the development of the KF. In the present study we investigated developmental changes in sPSCs and ePSCs of KF neurones in response to bath application (100 pM) of the neurotrophin BDNF in vitro . Whole cell patch clamp recordings of KF neurones at different postnatal stages (P1‐4, 5–10, 11–16, 17–21) revealed developmental influence of BDNF on sPSCs. At P1‐4 BDNF evoked a slight decrease in frequency of sPSCs (−14%), while at P5–10 we observed a slight increase (+20%) and in later stages this increase in sPSCs became more pronounced (P11–16, + 26%; P17–21, +64%). The modulation of sPSCs could be reversed with the application of the partial trkB antagonist K252a (50nM). The same pattern of BDNF mediated modulation was observed for the amplitude of glutamatergic ePSCs. In early neonatal stages the amplitude of ePSCs was decreased, while in later stages we observed increases in amplitude after BDNF application. We conclude that BDNF gains increasing importance as neuromodulator during postnatal development, what might affect the expression of network plasticity. funded by the DFG (SFB 406)