It is widely accepted that BDNF modulates NMDA receptor properties. The Kölliker Fuse nucleus (KF), an integral part of the pontine respiratory group abundantly expresses NMDA receptors. As the KF undergoes fundamental postnatal maturation we addressed the question if BDNF induced NMDA current modulation changes during the early postnatal development. Whole cell patch clamp recordings of KF neurones revealed age dependent modulation of the NMDA current amplitude after BDNF bath application (50pM). In neonates (postnatal day, P1-5; n=12) we found only marginal changes in NMDA current amplitude as analysed 2 min, 10 min and 20 min after BDNF. In intermediate age stages (P6-13, n=9) BDNF initially increased NMDA current amplitude by 17 ± 6% and remained enhanced at this level after 10 and 20 min (+19 ± 5%, +20 ± 8%). At juvenile age stages (P14-20, n=11) we found a progressive enhancement of NMDA amplitude after BDNF application (2 min BDNF: +14 ± 4%; 10 min BDNF: +28 ± 4%, 20 min BDNF: +35 ± 5%). We propose that BDNF induced modulation of NMDA receptor signalling in the KF requires a certain degree of maturation which might be linked with developmental changes of NMDA receptor subunit expression.

Supported by the DFG (SFB 406/12)