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Nature. 2017 Sep 21;549(7672):384-388. doi: 10.1038/nature23658. Epub 2017 Sep 13.

Hippocampal LTP and contextual learning require surface diffusion of AMPA receptors.

Penn AC1,2,3, Zhang CL1,2, Georges F1,2,4, Royer L1,2, Breillat C1,2, Hosy E1,2, Petersen JD1,2,5, Humeau Y1,2, Choquet D1,2,5.

Author information

1
University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR5297, F-33000 Bordeaux, France.
2
CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000 Bordeaux, France.
3
Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK.
4
University of Bordeaux, Institute of Neurodegenerative Diseases, CNRS UMR 5293, 146 Rue Léo Saignat, 33076 Bordeaux, France.
5
Bordeaux Imaging Center, UMS 3420 CNRS, US4 INSERM, University of Bordeaux, Bordeaux, France.

Abstract

Long-term potentiation (LTP) of excitatory synaptic transmission has long been considered a cellular correlate for learning and memory. Early LTP (less than 1 h) had initially been explained either by presynaptic increases in glutamate release or by direct modification of postsynaptic AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor function. Compelling models have more recently proposed that synaptic potentiation can occur by the recruitment of additional postsynaptic AMPA receptors (AMPARs), sourced either from an intracellular reserve pool by exocytosis or from nearby extra-synaptic receptors pre-existing on the neuronal surface. However, the exact mechanism through which synapses can rapidly recruit new AMPARs during early LTP remains unknown. In particular, direct evidence for a pivotal role of AMPAR surface diffusion as a trafficking mechanism in synaptic plasticity is still lacking. Here, using AMPAR immobilization approaches, we show that interfering with AMPAR surface diffusion markedly impairs synaptic potentiation of Schaffer collaterals and commissural inputs to the CA1 area of the mouse hippocampus in cultured slices, acute slices and in vivo. Our data also identify distinct contributions of various AMPAR trafficking routes to the temporal profile of synaptic potentiation. In addition, AMPAR immobilization in vivo in the dorsal hippocampus inhibited fear conditioning, indicating that AMPAR diffusion is important for the early phase of contextual learning. Therefore, our results provide a direct demonstration that the recruitment of new receptors to synapses by surface diffusion is a critical mechanism for the expression of LTP and hippocampal learning. Since AMPAR surface diffusion is dictated by weak Brownian forces that are readily perturbed by protein-protein interactions, we anticipate that this fundamental trafficking mechanism will be a key target for modulating synaptic potentiation and learning.

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PMID:
28902836
PMCID:
PMC5683353
DOI:
10.1038/nature23658
[Indexed for MEDLINE]
Free PMC Article

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