J Biol Rhythms 2010 Apr;25(2):92-102
Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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J Neurosci Res 2001 Dec;66(6):1133-9
Department of Pharmacology and Brain Science, School of Human Sciences, Waseda University, 2-5879-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan.
Aging alters circadian components such as the free-running period, the day-to-night activity ratio and photic entrainment in behavioral rhythms, and 2-deoxyglucose uptakes and neuronal firing in the suprachiasmatic nucleus (SCN). A core clock mechanism in the mouse SCN appears to involve a transcriptional feedback loop in which Period (Per) and Cryptochrome (Cry) genes play a role in negative feedback. The circadian rhythm systems include photic entrainment, clock oscillation, and outputs of clock information such as melatonin production. Read More
PLoS One 2012 11;7(6):e38985. Epub 2012 Jun 11.
Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.
The retina is both a sensory organ and a self-sustained circadian clock. Gene targeting studies have revealed that mammalian circadian clocks generate molecular circadian rhythms through coupled transcription/translation feedback loops which involve 6 core clock genes, namely Period (Per) 1 and 2, Cryptochrome (Cry) 1 and 2, Clock, and Bmal1 and that the roles of individual clock genes in rhythms generation are tissue-specific. However, the mechanisms of molecular circadian rhythms in the mammalian retina are incompletely understood and the extent to which retinal neural clocks share mechanisms with the suprachiasmatic nucleus (SCN), the central neural clock, is unclear. Read More
Chronobiol Int 2006 ;23(1-2):269-76
Département de Neurobiologie des Rythme, Institut des Neurosciences Cellulaires et Intégratives, Université Louis Pasteur, IFR des Neurosciences de Strasbourg, France.
Circadian rhythms are still expressed in animals that display daily torpor, implying a temperature compensation of the pacemaker. Nevertheless, it remains unclear how the clock works in hypothermic states and whether torpor itself, as a temperature pulse, affects the circadian system. To reveal changes in the clockwork during torpor, we compared clock gene and neuropeptide expression by in situ hybridization in the suprachiasmatic nucleus (SCN) and pineal gland of normothermic and torpid Djungarian hamsters (Phodopus sungorus). Read More
Proc Natl Acad Sci U S A 2002 Aug 29;99(16):10801-6. Epub 2002 Jul 29.
National Science Foundation Center for Biological Timing and Department of Biology, University of Virginia, Charlottesville, VA 22904-4328, USA.
Circadian organization changes with age, but we do not know the extent to which age-related changes are the result of alterations in the central pacemakers, the peripheral oscillators, or the coupling mechanisms that hold the system together. By using transgenic rats with a luciferase (luc) reporter, we assessed the effects of aging on the rhythm of expression of the Period 1 (Per1) gene in the suprachiasmatic nucleus (SCN) and in peripheral tissues. Young (2 months) and aged (24-26 months) Per1-luc transgenic rats, entrained to light-dark cycles, were killed, and tissues were removed and cultured. Read More