Entrainment and coupling of the hamster suprachiasmatic clock by daily dark pulses

Autor: Jorge E. Mendoza, Etienne Challet, Paul Pévet
Přispěvatelé: Institut des Neurosciences Cellulaires et Intégratives (INCI), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 2009
Předmět:
Male
Calbindins
medicine.medical_specialty
[SDV]Life Sciences [q-bio]
Circadian clock
Cell Count
Motor Activity
Biology
03 medical and health sciences
Cellular and Molecular Neuroscience
S100 Calcium Binding Protein G
0302 clinical medicine
Biological Clocks
Cricetinae
Internal medicine
medicine
Animals
CLOCK Proteins
Circadian rhythm
Extracellular Signal-Regulated MAP Kinases
ComputingMilieux_MISCELLANEOUS
030304 developmental biology
Analysis of Variance
0303 health sciences
Mesocricetus
Suprachiasmatic nucleus
Intracellular Signaling Peptides and Proteins
Period Circadian Proteins
Darkness
Immunohistochemistry
Circadian Rhythm
CLOCK
Endocrinology
Light effects on circadian rhythm
Biophysics
Suprachiasmatic Nucleus
sense organs
Entrainment (chronobiology)
Proto-Oncogene Proteins c-fos
030217 neurology & neurosurgery
Zdroj: Journal of Neuroscience Research
Journal of Neuroscience Research, Wiley, 2009, 87 (3), pp.758-765. ⟨10.1002/jnr.21887⟩
ISSN: 1097-4547
0360-4012
Popis: The circadian rhythm of locomotor activity of hamsters kept in constant light (LL) can split into two distinct components that, in steady state, lie 180 degrees apart. The splitting phenomenon is the result of antiphase circadian oscillations between left and right sides of the suprachiasmatic nuclei (SCN), the master circadian clock in mammals. In unsplit hamsters housed in LL, a single dark pulse produces a phase-shift of the wheel-running activity rhythm, accompanied by a transient down-regulation of clock gene expression in the SCN. In the present study, we evaluated the effects of daily 1-hr dark pulses on wheel-running activity rhythm and on the expression of clock and nonclock proteins in the SCN of Syrian hamsters exposed to LL conditions. The results show that a daily 1-hr dark pulse entrained the rhythm of wheel-running activity of unsplit hamsters. In addition, in split animals, unimodal coupling of the two locomotor activity components was produced by daily 1-hr dark pulses. In the SCN, the effects of entrainment and unimodal coupling of the two separate components by dark observed in behavior were also evident in the bilateral expression of the proteins c-FOS, p-ERK, PERIOD 1, and calbindin. These results show that the bilaterally asymmetric SCN clock, underlying split circadian behavior, can be recoupled in phase and entrained by short daily dark exposure, indicating the synchronizing potency of darkness on the main circadian clock.
Databáze: OpenAIRE
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