J Biol Rhythms 2008 Apr;23(2):150-9
Department of Biology, University of Virginia, Charlottesville, VA, USA.
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Nat Neurosci 2002 May;5(5):399-400
Department of Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Spontaneous discharges of individual neurons in the suprachiasmatic nucleus (SCN) of Clock mutant mice were recorded for over 5 days in organotypic slice cultures and dispersed cell cultures using a multi-electrode dish. Circadian rhythms with periods of about 27 hours were detected in 77% of slice cultures and 15% of dispersed cell cultures derived from Clock/Clock homozygotes. These findings indicate that the Clock mutation lengthens the circadian period but does not abolish the circadian oscillation, and suggest an important role of intercellular communication in the expression of circadian rhythm in the SCN. Read More
J Biol Rhythms 2004 Feb;19(1):35-46
Department of Biology, Washington University, St. Louis, MO 63130, USA.
The mammalian SCN contains a biological clock that drives remarkably precise circadian rhythms in vivo and in vitro. This study asks whether the cycle-to-cycle variability of behavioral rhythms in mice can be attributed to precision of individual circadian pacemakers within the SCN or their interactions. The authors measured the standard deviation of the cycle-to-cycle period from 7-day recordings of running wheel activity, Period1 gene expression in cultured SCN explants, and firing rate patterns of dispersed SCN neurons. Read More
Eur J Neurosci 2002 Apr;15(7):1153-62
Division of Molecular Brain Science, Department of Brain Sciences, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
The suprachiasmatic nucleus (SCN) is the mammalian circadian pacemaker, which consists of thousands of oscillator cells. It is believed that the circadian oscillation in each cell is generated by the transcription/(post)-translation feedback loop of a set of clock genes. However, little is known about how these oscillator cells are organized to produce the robust circadian rhythms in the SCN. Read More
J Neurosci 2003 Feb;23(4):1441-50
Department of Physiology, University of Kentucky, Lexington, Kentucky 40536-0084, USA.
The endogenous circadian clock of the mammalian suprachiasmatic nucleus (SCN) can be reset by light to synchronize the biological clock of the brain with the external environment. This process involves induction of immediate-early genes such as the circadian clock gene Period1 (Per1) and results in a stable shift in the timing of behavioral and physiological rhythms on subsequent days. The mechanisms by which gene activation permanently alters the phase of clock neuron activity are unknown. Read More