The excitatory/inhibitory input to orexin/hypocretin neuron soma undergoes day/night reorganization.

Details

Serval ID
serval:BIB_C6CE76B503FC
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The excitatory/inhibitory input to orexin/hypocretin neuron soma undergoes day/night reorganization.
Journal
Brain structure & function
Author(s)
Laperchia C., Imperatore R., Azeez I.A., Del Gallo F., Bertini G., Grassi-Zucconi G., Cristino L., Bentivoglio M.
ISSN
1863-2661 (Electronic)
ISSN-L
1863-2653
Publication state
Published
Issued date
11/2017
Peer-reviewed
Oui
Volume
222
Number
8
Pages
3847-3859
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Abstract
Orexin (OX)/hypocretin-containing neurons are main regulators of wakefulness stability, arousal, and energy homeostasis. Their activity varies in relation to the animal's behavioral state. We here tested whether such variation is subserved by synaptic plasticity phenomena in basal conditions. Mice were sacrificed during day or night, at times when sleep or wake, respectively, predominates, as assessed by electroencephalography in matched mice. Triple immunofluorescence was used to visualize OX-A perikarya and varicosities containing the vesicular glutamate transporter (VGluT)2 or the vesicular GABA transporter (VGAT) combined with synaptophysin (Syn) as a presynaptic marker. Appositions on OX-A <sup>+</sup> somata were quantitatively analyzed in pairs of sections in epifluorescence and confocal microscopy. The combined total number of glutamatergic (Syn <sup>+</sup> /VGluT2 <sup>+</sup> ) and GABAergic (Syn <sup>+</sup> /VGAT <sup>+</sup> ) varicosities apposed to OX-A somata was similar during day and night. However, glutamatergic varicosities were significantly more numerous at night, whereas GABAergic varicosities prevailed in the day. Triple immunofluorescence in confocal microscopy was employed to visualize synapse scaffold proteins as postsynaptic markers and confirmed the nighttime prevalence of VGluT2 <sup>+</sup> together with postsynaptic density protein 95 <sup>+</sup> excitatory contacts, and daytime prevalence of VGAT <sup>+</sup> together with gephyrin <sup>+</sup> inhibitory contacts, while also showing that they formed synapses on OX-A <sup>+</sup> cell bodies. The findings reveal a daily reorganization of axosomatic synapses in orexinergic neurons, with a switch from a prevalence of excitatory innervation at a time corresponding to wakefulness to a prevalence of inhibitory innervations in the antiphase, at a time corresponding to sleep. This reorganization could represent a key mechanism of plasticity of the orexinergic network in basal conditions.
Keywords
Animals, Cerebral Cortex/metabolism, Cerebral Cortex/physiology, Electroencephalography, Male, Mice, Inbred C57BL, Neuronal Plasticity, Neurons/metabolism, Orexins/metabolism, Presynaptic Terminals/metabolism, Sleep, Synaptophysin, Vesicular Glutamate Transport Protein 2/metabolism, Vesicular Inhibitory Amino Acid Transport Proteins/metabolism, Wakefulness, GABA, Glutamate, Hypothalamus, Synaptic plasticity, Wake
Pubmed
Web of science
Create date
27/07/2017 14:16
Last modification date
20/08/2019 15:42
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