A brief period of sleep deprivation causes spine loss in the dentate gyrus of mice

https://doi.org/10.1016/j.nlm.2018.03.018Get rights and content
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Highlights

  • A short period of sleep deprivation reduces spine density in the dentate gyrus of the hippocampus.

  • Sleep deprivation has the most prominent effect on branched spines in the dentate gyrus.

  • The inferior blade of the dentate gyrus is more vulnerable to sleep loss than the superior blade.

Abstract

Sleep and sleep loss have a profound impact on hippocampal function, leading to memory impairments. Modifications in the strength of synaptic connections directly influences neuronal communication, which is vital for normal brain function, as well as the processing and storage of information. In a recently published study, we found that as little as five hours of sleep deprivation impaired hippocampus-dependent memory consolidation, which was accompanied by a reduction in dendritic spine numbers in hippocampal area CA1. Surprisingly, loss of sleep did not alter the spine density of CA3 neurons. Although sleep deprivation has been reported to affect the function of the dentate gyrus, it is unclear whether a brief period of sleep deprivation impacts spine density in this region. Here, we investigated the impact of a brief period of sleep deprivation on dendritic structure in the dentate gyrus of the dorsal hippocampus. We found that five hours of sleep loss reduces spine density in the dentate gyrus with a prominent effect on branched spines. Interestingly, the inferior blade of the dentate gyrus seems to be more vulnerable in terms of spine loss than the superior blade. This decrease in spine density predominantly in the inferior blade of the dentate gyrus may contribute to the memory deficits observed after sleep loss, as structural reorganization of synaptic networks in this subregion is fundamental for cognitive processes.

Keywords

Sleep loss
Dentate gyrus
Structural plasticity
Hippocampus
Dendritic spines
Granule cells

Abbreviations

BDNF
brain-derived neurotrophic factor
DG
Dendate Gyrus
EGFP
enhanced green fluorescent protein
LTP
long-term potentiation
NMDA
N-methyl-d-aspartate
NSD
non-sleep deprived
pCREB
phosphorylated cAMP response element-binding protein
PDE
phosphodiesterase
REM
rapid-eye movement
SD
sleep deprivation

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