In: Current Biology, 2006, vol. 16, no. 20, p. 2016-2022
Predicting time of food availability is key for survival in most animals. Under restricted feeding conditions, this prediction is manifested in anticipatory bouts of locomotor activity and body temperature. This process seems to be driven by a food-entrainable oscillator independent of the main, light-entrainable clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus 1 and 2....
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In: Psychopharmacology, 2007, vol. 190, no. 1, p. 13-19
Rationale Alcohol consumption shows circadian rhythmicity, i.e., alcohol preference and intake change with circadian time. Circadian rhythmicity is controlled by a biological clock, which has been shown to govern behavioral, physiological, and hormonal processes in synchronization with internal as well as external cues. Molecular components of the clock include circadian clock genes such as...
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In: The Journal of Biological Chemistry, 2006, vol. 281, no. 23, p. 15671–15679
Synaptic strength depends on the amount of neurotransmitter stored in synaptic vesicles. The vesicular transmitter content has recently been shown to be directly dependent on the expression levels of vesicular neurotransmitter transporters indicating that the transport capacity of synaptic vesicles is a critical determinant for synaptic efficacy. Using synaptic vesicles prepared from whole brain...
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In: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology, 2006, vol. 192, no. 7, p. 769-775
Biological clocks have evolved in all kinds of organisms in order to anticipate and adjust to the daily light–dark cycle. Within the last decade, the molecular machinery underlying the circadian system was unraveled. In the present study, the impact of the loss of the Per1 or Per2 genes, key components of the core clock oscillator, on body mass, food and water intake, glucose...
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In: Journal of Biological Rhythms, 2006, vol. 21(3), p. 169-176
In mammals, circadian rhythms in behavior and physiology are controlled by a central pacemaker, the SCN, and subordinated clocks throughout the body. On the molecular level, these clocks are based on transcriptional/translational feedback loops involving a set of clock genes that regulate their own transcription. Among the components driving the mammalian circadian clock are the Period 1...
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In: Journal of Neural Transmission, 2006, vol. 113, no. 3, p. 347-356
Learning and memory, like most physiological processes, seem to be under the control of circadian rhythm. The recently cloned mPer1 and mPer2 genes play an important role in the regulation of the circadian rhythm. In this study, we tested mPer1 and mPer2 mutant mice in two different learning and memory paradigms, a water-maze place navigation task and contextual...
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In: Chronobiology International, 2006, vol. 23, no. 1-2, p. 51–157
A functional circadian clock has long been considered a selective advantage. Accumulating evidence shows that the clock coordinates a variety of physiological processes in order to schedule them to the optimal time of day and thus to synchronize metabolism to changes in external conditions. In mitochondria, both metabolic and cellular defense mechanisms are carefully regulated. Abnormal clock...
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In: Biological Procedures Online, 2005, vol. 7, p. 101-116
Most behavioral experiments within circadian research are based on the analysis of locomotor activity. This paper introduces scientists to chronobiology by explaining the basic terminology used within the field. Furthermore, it aims to assist in designing, carrying out, and evaluating wheel-running experiments with rodents, particularly mice. Since light is an easily applicable stimulus that...
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In: European Journal of Neuroscience, 2006, vol. 23, no. 4, p. 1082-1086
We developed a non-invasive method to measure and quantify human circadian PER2 gene expression in oral mucosa samples and show that this gene oscillates in a circadian (= about a day) fashion. We also have the first evidence that induction of human PER2 expression is stimulated by exposing subjects to 2 h of light in the evening. This increase in PER2 expression was statistically significant...
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In: Journal of Biological Rhythms, 2006, vol. 21, no. 2, p. 149-154
A genetic approach was used to investigate whether the emergence of circadian rhythms in murine pups is dependent on a functional maternal clock. Arrhythmic females bearing either the mPer1Brdm1/Per2Brdm1 or mPer2Brdm1/Cry1-/- double-mutant genotype were crossed with wild-type males under constant darkness. The heterozygous offspring have the genetic...
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