Ultrastructural Correlates of Presynaptic Functional Heterogeneity in Hippocampal Synapses.

ABSTRACT: Although similar in molecular composition, synapses can exhibit strikingly distinct functional transmitter release and plasticity characteristics. To determine whether ultrastructural differences co-define this functional heterogeneity, we combine hippocampal organotypic slice cultures, high-pressure freezing, freeze substitution, and 3D-electron tomography to compare two functionally distinct synapses: hippocampal Schaffer collateral and mossy fiber synapses. We find that mossy fiber synapses, which exhibit a lower release probability and stronger short-term facilitation than Schaffer collateral synapses, harbor lower numbers of docked synaptic vesicles at active zones and a second pool of possibly tethered vesicles in their vicinity. Our data indicate that differences in the ratio of doc

SUBMITTER: Maus L 

PROVIDER: S-EPMC7090384 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature