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Neuroglial and synaptic rearrangements associated with photic entrainment of the circadian clock in the suprachiasmatic nucleus

Neuroglial and synaptic rearrangements associated with photic entrainment of the circadian clock in the suprachiasmatic nucleus

Authors :
Clémence Girardet
Denis Becquet
Marie-Pierre Blanchard
Anne-Marie François-Bellan
Olivier Bosler
Centre de recherche en neurobiologie - neurophysiologie de Marseille (CRN2M)
Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
Source :
European Journal of Neuroscience, European Journal of Neuroscience, 2010, 32 (12), pp.2133-42. ⟨10.1111/j.1460-9568.2010.07520.x⟩, European Journal of Neuroscience, Wiley, 2010, 32 (12), pp.2133-42. ⟨10.1111/j.1460-9568.2010.07520.x⟩
Publication Year :
2010
Publisher :
HAL CCSD, 2010.

Abstract

International audience; Rhythmic biological functions in mammals are orchestrated by a circadian timekeeper in the suprachiasmatic nucleus of the hypothalamus (SCN) which precisely adjusts clock outputs to solar time through the process of photic synchronization. Entrainment to the 24-h light-dark cycle is known to act on the molecular loops which trigger circadian oscillations but is also thought to involve day-night adjustments in the intercellular phasing of the multiple component SCN oscillators. This view is supported by data showing that the SCN undergoes important rearrangements of its neuroglial architecture throughout the 24-h cycle. The present paper highlights our data showing in rat that the two main sources of SCN efferents, composed of neurons synthesizing either vasopressin (AVP) or vasoactive intestinal peptide (VIP), are differentially involved in day-night SCN neuroglial plasticity. We found that the synaptic inputs received by the VIP neurons, which are major integrators of photic signals in the retinorecipient SCN subregion, increased during the day while those received by the AVP neurons remained unchanged at day and night. Glutamatergic axons, known to convey photic information from the retina, together with nonglutamatergic axons, contribute to the synaptic remodellings on VIP neurons. Experimental data providing strong indication that these plastic events may subserve synchronization of the clock to the light-dark cycle and that the daily fluctuations of plasma glucocorticoid hormones may act as temporal endocrine signals that may modulate SCN neuroglial plasticity through the rhythmic release of serotonin are also reviewed.

Details

Language :
English
ISSN :
0953816X and 14609568
Database :
OpenAIRE
Journal :
European Journal of Neuroscience, European Journal of Neuroscience, 2010, 32 (12), pp.2133-42. ⟨10.1111/j.1460-9568.2010.07520.x⟩, European Journal of Neuroscience, Wiley, 2010, 32 (12), pp.2133-42. ⟨10.1111/j.1460-9568.2010.07520.x⟩
Accession number :
edsair.doi.dedup.....43407c21e184439e1c604ebbdb998883
Full Text :
https://doi.org/10.1111/j.1460-9568.2010.07520.x⟩