 | BDNF induces a long-lasting potentiation of synaptic transmission in visual cortex in vivo in young but not adult rats
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| | Bin Jiang2), Minoru Ohshima2), Satoshi Ichisaka1)2), Yoshio Hata1)2) and Tadaharu Tsumoto1)2) |
| 1) Osaka University Graduate School of Medicine
2) CREST·JST |
| | Brain-derived neurotrophic factor (BDNF) has been reported to rapidly enhance excitatory synaptic transmission in visual cortical slices in vitro. To date, however, a question of how long such an acute action lasts remains unanswered yet, since it is not possible to observe synaptic responses longer than several hours in slice preparations. To address this question, therefore, we analyzed effects of a brief application of BDNF for 20 min on synaptic transmission in visual cortex of urethane-anesthetized rats for 10-24 hours. Field potentials evoked by stimulation of the lateral geniculate nucleus were recorded simultaneously from two sites separated by 3 mm in the visual cortex of the same hemisphere. BDNF or Cytochrome C (CytC) was injected into each site through a cannula glued to recording electrodes. The application of BDNF induced a slowly developing increase in the amplitude of field potentials in the young rats (Postnatal days 13-17 and 19-24). The potentiation reached the maximum level 3-4 hours after the BDNF infusion, remained stable from 4 to 8 hours, and then gradually decreased to the baseline level around 15-16 hours after the injection. The amplitude of cortical field potential were 139.3±25.6%(mean±SD, n=10) and 132.2±21.3% (n=12) of the control value 4 hours after the BDNF application in rats at P13-17 and P19-24, respectively. However such a BDNF-induced potentiation of cortical field potentials was not seen in adult rats. These results indicate that the brief application of BDNF induces synaptic potentiation lasting for several hours in the developing visual cortex, but does not in the matured cortex of rats. |
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