抄録
The activation of presynaptically silent synapses is one of mechanisms underlying learning and memory. To test if this mechanism is involved in the PKC-dependent potentiation of mossy fiber (MF)-CA3 synapse in the hippocampus, exocytosis at individual MF bouton was investigate. We used a TV-42 transgenic mouse line that expresses synaptopHluorin (SpH), one of optical probes measuring exo-endocytosis, specifically in the hippocampal MF boutons. The mouse was deeply ether-anesthetized and the brain was removed. The hippocampal slices were made at 400 μm. Individual large MF boutons were identified under confocal microscopy and the activity-dependent changes of SpH fluorescence were measured. We found that the individual MF boutons are variably responsive to PKC. Among them some presynaptically silent boutons became active. It is suggested hat PKC facilitates a transition of presynaptically silent synapses to be releasable. This transition may occur by switching non releasable active zones to releasable active zone. All animal procedures were conducted in accordance with the guiding principles of NIH. [J Physiol Sci. 2008;58 Suppl:S135]
