Université de Fribourg

Evening exposure to blue light stimulates the expression of the clock gene PER2 in humans

Cajochen, Christian ; Jud, Corinne ; Münch, Mirjam ; Kobialka, Szymon ; Wirz-Justice, Anna ; Albrecht, Urs

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...

Université de Fribourg

REV-ERBα regulates Fgf21 expression in the liver via hepatic nuclear factor 6

Chavan, Rohit ; Preitner, Nadia ; Okabe, Takashi ; Mansencal Strittmatter, Laureen ; Xu, Cheng ; Ripperger, Jürgen A. ; Pitteloud, Nelly ; Albrecht, Urs

In: Biology Open, 2017, vol. 6, no. 1, p. 1–7

The circadian clock contributes to the timing of many body functions including metabolism and reproduction. The hepatokine fibroblast growth factor 21 (FGF21) is a critical metabolic regulator involved in modulation of fertility. Here we show that lack of the clock component REV-ERBα elevates FGF21 levels in liver and plasma. At the molecular level, REV-ERBα modulates the expression of...

Université de Fribourg

Liver-derived ketone bodies are necessary for food anticipation

Chavan, Rohit ; Feillet, Céline ; Costa, Sara S. Fonseca ; Delorme, James E. ; Okabe, Takashi ; Ripperger, Jürgen A. ; Albrecht, Urs

In: Nature Communications, 2016, vol. 7, p. 10580

The circadian system has endowed animals with the ability to anticipate recurring food availability at particular times of day. As daily food anticipation (FA) is independent of the suprachiasmatic nuclei, the central pacemaker of the circadian system, questions arise of where FA signals originate and what role components of the circadian clock might play. Here we show that liver-specific...

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

The mammalian circadian timing system: organization and coordination of central and peripheral clocks

Dibner, Charna ; Schibler, Ueli ; Albrecht, Urs

In: Annual Review of Physiology, 2010, vol. 72, p. 517-549

Most physiology and behavior of mammalian organisms follow daily oscillations. These rhythmic processes are governed by environmental cues (e.g., fluctuations in light intensity and temperature), an internal circadian timing system, and the interaction between this timekeeping system and environmental signals. In mammals, the circadian timekeeping system has a complex architecture, composed of a...

Université de Fribourg

Cones are required for normal temporal responses to light of phase shifts and clock gene expression

Dollet, Anna ; Albrecht, Urs ; Cooper, Howard M. ; Dkhissi-Benyahya, Ouria

In: Chronobiology International, 2010, vol. 27, no. 4, p. 768-781

In mammals, non-visual responses to light involve intrinsically photosensitive melanopsin-expressing retinal ganglion cells (ipRGCs) that receive synaptic inputs from rod and cone photoreceptors. Several studies have shown that cones also play a role in light entrainment, photic responses of the suprachiasmatic nucleus (SCN), pupil constriction, and sleep induction. These studies suggest that...

Université de Fribourg

Effects of the circadian rhythm gene period 1 (Per1) on psychosocial stress-Induced alcohol drinking

Dong, Li ; Bilbao, Ainhoa ; Laucht, Manfred ; Henriksson, Richard ; Yakovleva, Tatjana ; Ridinger, Monika ; Desrivieres, Sylvane ; Clarke, Toni-Kim ; Lourdusamy, Anbarasu ; Smolka, Michael N. ; Cichon, Sven ; Blomeyer, Dorothea ; Treutlein, Jens ; Perreau-Lenz, Stephanie ; Witt, Stephanie ; Leonardi-Essmann, Fernando ; Wodarz, Norbert ; Zill, Peter ; Soyka, Michael ; Albrecht, Urs ; Rietschel, Marcella ; Lathrop, Mark ; Bakalkin, Georgy ; Spanagel, Rainer ; Schumann, Gunter

In: American Journal of Psychiatry, 2011, vol. 168, no. 10, p. 1090-1098

Objective: Circadian and stress-response systems mediate environmental changes that affect alcohol drinking. Psychosocial stress is an environmental risk factor for alcohol abuse. Circadian rhythm gene period 1 (Per1) is targeted by stress hormones and is transcriptionally activated in corticotropin releasing factor-expressing cells. The authors hypothesized that Per1 is involved in ...

Université de Fribourg

Differences in locomotor behavior revealed in mice deficient for the calcium-binding proteins parvalbumin, calbindin D-28k or both

Farré-Castany, Maria A. ; Schwaller, Beat ; Gregory, Patrick ; Barski, Jaroslaw ; Mariethoz, Céline ; Eriksson, Jan L. ; Tetko, Igor V. ; Wolfer, David ; Celio, Marco R. ; Schmutz, Isabelle ; Albrecht, Urs ; Villa, Alessandro E.P.

In: Behavioural Brain Research, 2007, vol. 178, no. 2, p. 250-261

We investigated the role of the two calcium-binding proteins parvalbumin (PV) and calbindin D-28k (CB) in the locomotor activity and motor coordination using null-mutant mice for PV (PV−/−), CB (CB−/−) or both proteins (PV−/−CB−/−). These proteins are expressed in distinct, mainly non-overlapping populations of neurons of the central and peripheral nervous system and PV...

Université de Fribourg

Lack of Food Anticipation in Per2 Mutant Mice

Feillet, Céline A. ; Ripperger, Jürgen A. ; Magnone, Maria Chiara ; Dulloo, Abdul G. ; Albrecht, Urs ; Challet, Etienne

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....