MilliporeSigma
  • Ultrastructural Correlates of Presynaptic Functional Heterogeneity in Hippocampal Synapses.

Ultrastructural Correlates of Presynaptic Functional Heterogeneity in Hippocampal Synapses.

Cell reports (2020-03-19)
Lydia Maus, ChoongKu Lee, Bekir Altas, Sinem M Sertel, Kirsten Weyand, Silvio O Rizzoli, JeongSeop Rhee, Nils Brose, Cordelia Imig, Benjamin H Cooper
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 docked versus tethered vesicles at active zones contribute to distinct functional characteristics of synapses.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Biocytin, ≥98% (TLC)
Sigma-Aldrich
Tannic acid, ACS reagent
Sigma-Aldrich
Kynurenic acid, ≥98%
Millipore
Sodium citrate, dihydrate, Molecular Biology Grade
Sigma-Aldrich
Forskolin, For use in molecular biology applications
Sigma-Aldrich
Biocytin hydrochloride, ≥98% (TLC)
Sigma-Aldrich
Dodecenylsuccinic anhydride, mixture of isomers, technical grade, 90%
Millipore
Millicell® Standing Cell Culture Inserts, pore size 0.4 μm, diam. 30 mm, transparent PTFE membrane, hydrophilic, H 13 mm, size 6 wells, sterile