Université de Fribourg

Age-dependent alterations in human PER2 levels after early morning blue light exposure

Jud, Corinne ; Chappuis, Sylvie ; Revell, Victoria L. ; Sletten, Tracey L. ; Saaltink, Dirk-Jan ; Cajochen, Christian ; Skene, Debra J. ; Albrecht, Urs

In: Chronobiology International, 2009, vol. 26, no. 7, p. 1462-1469

In our modern society, we are exposed to different artificial light sources that could potentially lead to disturbances of circadian rhythms and, hence, represent a risk for health and welfare. Investigating the acute impact of light on clock-gene expression may thus help us to better understand the mechanisms underlying disorders rooted in the circadian system. Here, we show an overall...

Université de Fribourg

Altered sleep homeostasis in rev-erbα knockout mice

Mang, Géraldine M. ; La Spada, Francesco ; Emmenegger, Yann ; Chappuis, Sylvie ; Ripperger, Jürgen A. ; Albrecht, Urs ; Franken, Paul

In: SLEEP, 2016, vol. 39, no. 3, p. 589–601

Study Objectives: The nuclear receptor REV-ERBα is a potent, constitutive transcriptional repressor critical for the regulation of key circadian and metabolic genes. Recently, REV-ERBα's involvement in learning, neurogenesis, mood, and dopamine turnover was demonstrated suggesting a specific role in central nervous system functioning. We have previously shown that the brain expression of...

Université de Fribourg

Behavioural food-anticipation in clock genes deficient mice: confirming old phenotypes, describing new phenotypes

Mendoza, Jorge ; Albrecht, Urs ; Challet, Etienne

In: Genes, Brain and Behavior, 2010, vol. 9, p. -

Animals fed daily at the same time exhibit circadian food-anticipatory activity (FAA), which has been suggested to be driven by one or several food-entrainable oscillators (FEOs). FAA is altered in mice lacking some circadian genes essential for timekeeping in the main suprachiasmatic clock (SCN). Here we confirmed that single mutations of clock genes Per1−/− and...

Université de Fribourg

cGMP-dependent protein kinase I, the circadian clock, sleep, and learning

Feil, Robert ; Hölter, Sabine M. ; Weindl, Karin ; Wurst, Wolfgang ; Langmesser, Sonja ; Gerling, Andrea ; Feil, Susanne ; Albrecht, Urs

In: Communicative & Integrative Biology, 2009, vol. 2, no. 4, p. 298 - 301

The second messenger cGMP controls cardiovascular and gastrointestinal homeostasis in mammals. However, its physiological relevance in the nervous system is poorly understood. Now, we have reported that the cGMP-dependent protein kinase type I (PRKG1) is implicated in the regulation of the timing and quality of sleep and wakefulness. Prkg1 mutant mice showed altered distribution of sleep and...

Université de Fribourg

cGMP-dependent protein kinase type I is implicated in the regulation of the timing and quality of sleep and wakefulness

Langmesser, Sonja ; Franken, Paul ; Feil, Susanne ; Emmenegger, Yann ; Albrecht, Urs ; Feil, Robert

In: PLoS ONE, 2009, vol. 4, no. 1, p. e4238

Many effects of nitric oxide (NO) are mediated by the activation of guanylyl cyclases and subsequent production of the second messenger cyclic guanosine-3′,5′-monophosphate (cGMP). cGMP activates cGMP-dependent protein kinases (PRKGs), which can therefore be considered downstream effectors of NO signaling. Since NO is thought to be involved in the regulation of both sleep and circadian...

Université de Fribourg

Changing the light schedule in late pregnancy alters birth timing in mice

Amano, Tomoko ; Ripperger, Jürgen A. ; Albrecht, Urs

In: Theriogenology, 2020, vol. 154, p. 212–222

In rats, birth timing is affected by changes in the light schedule until the middle of the pregnancy period. This phenomenon can be used to control birth timing in the animal industry and/or clinical fields. However, changes in the light schedule until the middle of the pregnancy period can damage the fetus by affecting the development of the major organs. Thus, we compared birth timing in...

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

The circadian clock, metabolism and obesity

Albrecht, Urs

In: Obesity Reviews, 2017, vol. 18, no. S1, p. 25–33

In the last decades, obesity has been on the rise becoming a burden for health care systems. The reasons behind this rise are most likely caused by lifestyle rather than by an increase in gene mutations, because manifestations of genetic alterations would take longer than just a few decades. Lifestyle has a great impact on the circadian system and therefore on the body internal organization...

Université de Fribourg

The circadian clock, reward, and memory

Albrecht, Urs

In: Frontiers in Molecular Neuroscience, 2011, vol. 4, no. 41, p. -

During our daily activities, we experience variations in our cognitive performance, which is often accompanied by cravings for small rewards, such as consuming coffee or chocolate. This indicates that the time of day, cognitive performance, and reward may be related to one another. This review will summarize data that describe the influence of the circadian clock on addiction and mood-related...