Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents.

Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents. Research Abstract Details 

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Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents. Abstract Text:

Jorge Mendoza,Florent G Revel,Paul ,Etienne Challet,

The master circadian clock in mammals, located in the suprachiasmatic nuclei (SCN) of the hypothalamus, is entrained by light and behavioural stimulation. In addition, the SCN can be reset by dark pulses in nocturnal rodents under constant light conditions. Here, the shifting effects of a dark pulse on the SCN clock were detailed at both a behavioural and molecular level in a nocturnal rodent (Syrian hamster), and were compared to those of a diurnal rodent (Arvicanthis ansorgei). Four-hour dark pulses led to phase advances in the circadian rhythm of locomotor activity from subjective midday to dusk in hamsters, but from subjective dusk to midnight in Arvicanthis. Moreover, dark pulses had no resetting effect during the middle of the subjective night in hamsters, while such a dead shifting zone occurred during most of the subjective day in Arvicanthis. The behavioural phase advances in both hamsters and Arvicanthis were most often accompanied by marked downregulation of the clock genes Per1 and/or Per2 in the SCN, and also by changes in the transforming growth factor-alpha expression, a neuropeptide that suppresses daytime activity in nocturnal mammals. Despite that both hamsters and Arvicanthis showed dark-induced phase advances at circadian time-12, Per1 gene and its protein PER1 were downregulated in Arvicanthis but not in hamsters. Altogether these results show that dark resetting of the SCN is always associated with downregulation of Per1 and/or Per2 expression, and mostly occurs during resting. Thus, the circadian window of sensitivity to dark differs between nocturnal and diurnal rodents.

Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents. Publishing Authors By Initials

J Mendoza,FG Revel,P ,E Challet,

For similar peptides: intercellular signaling peptides and proteins: transforming growth factors: transforming growth factor alpha research abstracts see: peptides: intercellular signaling peptides and proteins: transforming growth factors: transforming growth factor alpha research

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Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents. Journal Published:

PUBLICATION TYPE: Research Support, Non-U.S. Gov

Journal: The European journal of neuroscience

VOLUME: 25

Page Numbers: 3080-90

Journal Abbreviation: Eur. J. Neurosci.

ISSN: 0953-816X

DAY: 19

MONTH: May

YEAR: 2007

Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents. Information

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LANGUAGE: eng

NlmUniqueID: 8918110

Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents. Keywords Mesh Terms:

KEYWORDS: Transforming Growth Factor alpha

MESH TERMS: metabolism

Chemical & Substance for Abstract: Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents. Information

Substance Name: Transforming Growth Factor alpha

Registry Number: 0

Grant and Affiliation Information for Shedding light on circadian clock resetting by dark exposure: differential effects between diurnal and nocturnal rodents.

AFFILIATION: Institut de Neurosciences Cellulaires et Intégratives, Département de Neurobiologie des Rythmes UMR7168/LC2, CNRS et Université Louis Pasteur, 67084 Strasbourg Cedex, France. jmendoza@neurochem.u-strasbg.fr

Country: France

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MEDLINETA: Eur J Neurosci

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