Dynamics of nascent and active zone ultrastructure as synapses enlarge during long-term potentiation in mature hippocampus.

摘要: Nascent zones and active are adjacent synaptic regions that share a postsynaptic density, but nascent lack the presynaptic vesicles found at zones. Here dendritic spine synapses were reconstructed through serial section electron microscopy (3DEM) EM tomography to investigate zone dynamics during long-term potentiation (LTP) in mature rat hippocampus. LTP was induced with thetaburst stimulation, comparisons made control stimulation same hippocampal slices 5 minutes, 30 2 hours post-induction perfusion-fixed hippocampus vivo. present edges of � 35% as many 50% some slice conditions. By small dense-core known transport proteins moved into more boutons. area decreased, without significant change synapse area, suggesting recruited preexisting hours, both enlarged. Immunogold labeling revealed glutamate receptors zones; however, average distances from docked ranged 170 6 nm 251 4 enlarged by LTP. Prior stochastic modeling suggests decrease concentration reduces probability receptor activation 0.4 center release 0.1 just 200 away. Thus, conversion functional likely requires recruitment J. Comp. Neurol. 522:3861–3884, 2014.