Elsevier

Neuroscience

Volume 323, 26 May 2016, Pages 135-156
Neuroscience

Review
Regulation of neuron–astrocyte metabolic coupling across the sleep–wake cycle

https://doi.org/10.1016/j.neuroscience.2015.12.007Get rights and content
Under a Creative Commons license
open access

Highlights

  • Astrocytes adjust local energy production to neuronal energy needs.

  • The “neurometabolic coupling” (NMC) mechanisms interact with sleep regulation.

  • Astrocyte network plays a role in sleep/NMC interactions.

  • Astrocytic NMC fit the “local and use dependent” sleep hypothesis.

Abstract

Over the last thirty years, a growing number of studies showed that astrocytes play a pivotal role in the energy support to synapses. More precisely, astrocytes adjust energy production to neuronal energy needs through different mechanisms grouped under the term “neurometabolic coupling” (NMC). In this review we describe these mechanisms of coupling and how they involve astrocytes. From a physiological point of view, these mechanisms of coupling are particularly important to ensure normal synaptic functioning when neurons undergo rapid and repetitive changes in the firing rate such as during the sleep/wake transitions.

Investigations into brain energy metabolism during the sleep/wake cycle have been mainly focused on glucose (Gluc) consumption and on glycogen metabolism. However, the recent development of substrate-specific biosensors allowed measurements of the variation in extracellular levels of glutamate, Gluc and lactate (Lac) with a time resolution compatible with sleep stage duration. Together with gene expression data these experiments allowed to better define the variations of energy metabolite regulation across the sleep/wake cycle.

The aim of this review is to bring into perspective the role of astrocytes and NMC in the regulation of the sleep/wake cycle. The data reviewed also suggest an important role of the astrocytic network. In addition, the role of astrocytes in NMC mechanisms is consistent with the “local and use dependent” sleep hypothesis.

Abbreviations

Ade
adenosine
ADP
adenosine di-phosphate
ANLS
astrocyte–neuron lactate shuttle
ATP
adenosine tri-phosphate
DAB
1,4-dideoxy-1,4-imino-d-arabinitol
EEG
electro-encephalogram
EMG
electro-myogram
EOG
electrooculogram
FDG
fluoro-deoxy glucose
GLAST
glutamate–aspartate transporter
Gln
glutamine
GLT1
glutamate transporter type-1
Glu
glutamate
Gluc
glucose
GLUT
glucose transporter
GPhos
glycogen phosphorylase
GS
glutamine synthase
GSynt
glycogen synthase
Lac
lactate
LDH
lactate dehydrogenase
LGCU
local glucose uptake
MCT
mono-carboxylate transporter
NA
noradrenaline
NMC
neuro-metabolic coupling
NREM
Non-Rapid Eye Movement sleep
PET
positron emission tomography
PFK
phospho-fructo kinase
PPP1
protein phosphatase 1
PS
Paradoxical Sleep
PTG
protein targeting to glycogen
SWA
slow wave activity
SWS
slow-wave sleep
SF
sleep fragmentation
TSD
total sleep deprivation
VIP
vasoactive intestinal peptide
W
waking

Key words

lactate
glucose
glutamate
adenosine
locus coeruleus
gap-junctions

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