Université de Fribourg

The circadian clock and mood-related behavior : addendum to Hampp G. et al., Regulation of monoamine oxidase a by circadian-clock components implies clock influence on mood. Curr Biol 18:678–83, 2008.

Hampp, Gabriele ; Albrecht, Urs

In: Communicative & Integrative Biology, 2008, vol. 1, no. 1, p. 1-3

Over many years evidence accumulated that circadian rhythms are related to psychiatric disorders.1-3 However, a mechanistic relationship between the circadian clock and mood related behaviors remained enigmatic. Now, we have reported that monoamine oxidase A (MAOA), a mitochondrial enzyme degrading catecholamines including dopamine, is regulated by components of the circadian clock .4...

Université de Fribourg

Mutation of the circadian clock gene Per2 alters vascular endothelial function

Viswambharan, Hema ; Carvas, João Miguel ; Antic, Vladan ; Marecic, Ana ; Jud, Corinne ; Zaugg, Christian E. ; Ming, Xiu-Fen ; Montani, Jean-Pierre ; Albrecht, Urs ; Yang, Zhihong

In: Circulation, 2007, vol. 115, p. 2188-2195

Background— The circadian clock regulates biological processes including cardiovascular function and metabolism. In the present study, we investigated the role of the circadian clock gene Period2 (Per2) in endothelial function in a mouse model. Methods and Results— Compared with the wild-type littermates, mice with Per2 mutation exhibited impaired...

Université de Fribourg

Differential Sorting of the Vesicular Glutamate Transporter 1 into a Defined Vesicular Pool Is Regulated by Light Signaling Involving the Clock Gene Period2

Yelamanchili, Sowmya V. ; Pendyala, Gurudutt ; Brunk, Irene ; Darna, Mahesh ; Albrecht, Urs ; Ahnert-Hilger, Gudrun

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...

Université de Fribourg

Impaired daily glucocorticoid rhythm in Per1Brd mice

Dallmann, Robert ; Touma, Chadi ; Palme, Rupert ; Albrecht, Urs ; Steinlechner, Stephan

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...

Université de Fribourg

Life time—circadian clocks, mitochondria and metabolism

Langmesser, Sonja ; Albrecht, Urs

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...

Université de Fribourg

Circadian rhythms in murine pups develop in absence of a functional maternal circadian clock

Jud, Corinne ; Albrecht, Urs

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...

Université de Fribourg

Phase Responses to Light Pulses in Mice Lacking Functional per or cry Genes

Spoelstra, Kamiel ; Albrecht, Urs ; Horst, Gijsbertus T. J. van der ; Brauer, Verena ; Daan, Serge

In: Journal of Biological Rhythms, 2004, vol. 19 (6), p. 518-529

The phase-resetting properties of the circadian system in mice with a functional deletion in mCry1, mCry2, mPer1, or mPer2 were studied in 2 experiments. In experiment 1, mCry1-/- and mCry2-/- mice as well as mPer1Brdm1 and mPer2Brdm1 mutant mice were exposed to 15-min light pulses during the 1st cycle following entrainment, either early (external time [ExT] 20) or late (ExT 4) in the subjective...