抄録
Brain-derived neurotrophic factor (BDNF), which was first identified as a molecule regulating neuronal survival and differentiation, has a pivotal role in the regulation of synaptic plasticity, especially long-term potentiation (LTP). Recent studies have shown that BDNF is transported anterogradely along axon and stored in the presynaptic terminals. The mossy fiber (MF) terminals, which are axon terminals of the granule cells in the dentate gyrus (DG) of the hippocampus, contain the highest concentration of BDNF in the CNS. These observations led us to hypothesize that BDNF is released from MF terminals and that its release is dependent on the activity pattern. We made a Sindbis virus vector containing a mRNA coding the fusion protein constract of BDNF and Venus, one of green fluorescent protein derivatives, and inoculated it stereotaxically to the DG cells of mouse hippocampus (P14-21). After 2-3 days, MF boutons accumulating BDNF-Venus were identified in the acute slice under confocal microscopy. The activity-dependent BDNF release was measured as a reduction of the fluorescence intensity of the individual presynaptic terminal. We found that the activity patterns as high frequency stimulation and theta-burst stimulation are more effective on the BNDF release than low frequency stimulation. It is suggested that BDNF is released from the MF terminals during induction of LTP. [J Physiol Sci. 2006;56 Suppl:S169]
