| Rat photoreceptor circadian oscillator strongly relies on lighting conditions. | |
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MedLine Citation:
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PMID: 21771113 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Mammalian retina harbours a self-sustained circadian clock able to synchronize to the light : dark (LD) cycle and to drive cyclic outputs such as night-time melatonin synthesis. Clock genes are expressed in distinct parts of the tissue, and it is presently assumed that the retina contains several circadian oscillators. However, molecular organization of cell type-specific clockworks has been poorly investigated. Here, we questioned the presence of a circadian clock in rat photoreceptors by studying 24-h kinetics of clock and clock output gene expression in whole photoreceptor layers isolated by vibratome sectioning. To address the importance of light stimulation towards photoreceptor clock properties, animals were exposed to 12 : 12 h LD cycle or 36 h constant darkness. Clock, Bmal1, Per1, Per2, Cry1, Cry2, RevErbα and Rorβ clock genes were all found to be expressed in photoreceptors and to display rhythmic transcription in LD cycle. Clock genes in whole retinas, used as a reference, also showed rhythmic expression with marked similarity to the profiles in pure photoreceptors. In contrast, clock gene oscillations were no longer detectable in photoreceptor layers after 36 h darkness, with the exception of Cry2 and Rorβ. Importantly, transcripts from two well-characterized clock output genes, Aanat (arylalkylamine N-acetyltransferase) and c-fos, retained sustained rhythmicity. We conclude that rat photoreceptors contain the core machinery of a circadian oscillator likely to be operative and to drive rhythmic outputs under exposure to a 24-h LD cycle. Constant darkness dramatically alters the photoreceptor clockwork and circadian functions might then rely on inputs from extra-photoreceptor oscillators. |
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Authors:
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Cristina Sandu; David Hicks; Marie-Paule Felder-Schmittbuhl |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-7-19 |
Journal Detail:
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Title: The European journal of neuroscience Volume: - ISSN: 1460-9568 ISO Abbreviation: - Publication Date: 2011 Jul |
Date Detail:
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Created Date: 2011-7-20 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8918110 Medline TA: Eur J Neurosci Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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© 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd. |
Affiliation:
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Département de Neurobiologie des Rythmes, CNRS UPR 3212 - Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France. |
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