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Experience-specific plasticity at excitatory and inhibitory synapses onto granule cells in the dentate gyrus

The bulletin of the Yamaguchi Medical School Volume 69 Issue 1-2 Page 11-19
published_at 2022-06
A05069000102
947 KB
Title
Experience-specific plasticity at excitatory and inhibitory synapses onto granule cells in the dentate gyrus
Abstract
The hippocampal dentate gyrus has been identified to play a critical role in maintaining contextual memory in many mammalian species. To evaluate learninginduced synaptic plasticity of granule cells, we subjected male rats to an inhibitory avoidance (IA) task and prepared acute hippocampal slices. In the presence of 0.5 μM tetrodotoxin, we recorded miniature excitatory post synaptic currents (mEPSCs) and inhibitory post synaptic currents (mIPSCs) in male rats experiencing four groups: untrained, IA-trained, unpaired, and walk-through. Compared with the untrained, IA-trained, unpaired, and walk-through groups, the unpaired group significantly enhanced mean mEPSC amplitudes, suggesting the experience-induced plasticity at AMPA receptor-mediated excitatory synapses. For inhibitory synapses, both unpaired and walk-through groups significantly decreased mean mIPSC amplitudes, showing the experience-induced reduction of postsynaptic GABAA receptor-mediated currents. Unlike the plasticity at CA1 synapses, it was difficult to explain the learning- specific plasticity at the synapses. However, overall multivariate analysis using four variables of mE(I)PSC responses revealed experience-specific changes in the diversity, suggesting that the diversity of excitatory/inhibitory synapses onto granule cells differs among the past experience of animals include the learning. In comparison with CA1 pyramidal neurons, granule cells consistently showed greater amplitude and frequency of mE(I)PSCs. Fluctuation analysis further revealed that granule cells provide more postsynaptic AMPA receptor channels and greater single-channel current of GABAA receptors of than CA1 pyramidal neurons. These findings show functional differences between two types of principal cells in the hippocampus.
Creators Han Thiri Zin
Creators Sakimoto Yuya
Affiliate Master Yamaguchi University
[kakenhi]15501 grid.268397.1
Creators Mitsushima Dai
Affiliate Master Yamaguchi University
[kakenhi]15501 grid.268397.1
Source Identifiers [PISSN] 0513-1812 [EISSN] 2436-696X
Creator Keywords
AMPA receptor GABA_{A} receptor contextual learning synaptic plasticity granule cells
Languages eng
Resource Type departmental bulletin paper
Publishers Yamaguchi University School of Medicine
Date Issued 2022-06
File Version Version of Record
Access Rights open access
Funding Refs
Japan Society for the Promotion of Science
Award Learning-promoted synaptic diversity and a possible encording rule of CA1 pyramidal neurons 19H03402
Schools 大学院医学系研究科(医学)