Nav: Home

Chronobiology: Sleep and synaptic rhythms

October 11, 2019

Chronobiologists at Ludwig-Maximilians-Universitaet (LMU) in Munich, Germany, show in two articles in the journal Science how critical the sleep-wake cycle is for protein and phosphorylation dynamics in synapses to ultimately regulate its activity.

The internal clock controls virtually all physiological processes in the human body predicting daily recurring environmental changes such as day and night. How the circadian rhythm and sleep influences molecular mechanisms at the cellular level in the brain is not yet fully understood. Professor Maria Robles, head of a research group at the Institute of Medical Psychology at LMU Munich, shows in two recent articles published in the journal Science how sleep and wake cycles, rather than the circadian clock, drive cycles of protein abundance as well as phosphorylation in synaptic proteins to orchestrate dynamics of synaptic activity in the brain. "Our work shows that sleep-wake cycles play a central role in the temporal regulation of many aspects of synaptic functions," says Maria Robles. The LMU chronobiologist and her research group use mass spectrometry-based quantitative proteomics to profile daily dynamics of protein and phosphorylation in in vivo isolated synapses from mouse forebrain. For the studies in Science, the team investigated how synaptic proteome and phosphoproteome are dynamically shaped across the day and how it is affected by sleep deprivation. In one study the group shows that in a normal day, one fourth of the 8,000 phosphorylations in many critical synaptic proteins oscillates with two main peaks: one when the mice wake up and a second one just before they fall asleep. "This suggests that synaptic phosphorylation plays a key role in the regulation of synaptic function in particular at the sleep-wake-sleep transitions," says Maria Robles. This characteristic phosphorylation pattern seems to reflect buildup and dissipation of sleep and wake pressure since sleep deprivation almost completely abolished synaptic phosphorylation rhythms. "Our study shows that key synaptic processes, from house-keeping to plasticity are temporally regulated trough phosphorylation, in response to both sleep and wake pressure, " says Maria Robles.

In the second study published in the same issue of Science the same group, in collaboration with a group from the University of Zürich (Steve Brown), has showed that synaptic protein abundance is also rhythmically shaped by sleep-wake cycles. In particular, they demonstrated that synaptic activity triggers the cycling production of proteins from messenger molecules that rhythmically accumulate at the synapses across the day. While protein production completely depends on wake-sleep cycles, messenger molecules travel and accumulate in the synapses predominantly in response to circadian mechanisms.
-end-


Ludwig-Maximilians-Universität München

Related Sleep Articles:

'Short sleep' gene prevents memory deficits associated with sleep deprivation
The UCSF scientists who identified the two known human genes that promote 'natural short sleep' -- nightly sleep that lasts just four to six hours but leaves people feeling well-rested -- have now discovered a third, and it's also the first gene that's ever been shown to prevent the memory deficits that normally accompany sleep deprivation.
Short sleep duration and sleep variability blunt weight loss
High sleep variability and short sleep duration are associated with difficulties in losing weight and body fat.
Nurses have an increased risk of sleep disorders and sleep deprivation
According to preliminary results of a new study, there is a high prevalence of insufficient sleep and symptoms of common sleep disorders among medical center nurses.
Opioids are not sleep aids, and can actually worsen sleep research finds
Evidence that taking opioids will help people with chronic pain to sleep better is limited and of poor quality, according to an interdisciplinary team of psychologists and medics from the University of Warwick in partnership with Lausanne University Hospital, Switzerland.
Common sleep myths compromise good sleep and health
People often say they can get by on five or fewer hours of sleep, that snoring is harmless, and that having a drink helps you to fall asleep.
Sleep tight! Researchers identify the beneficial role of sleep
Why do animals sleep? Why do humans 'waste' a third of their lives sleeping?
Does extra sleep on the weekends repay your sleep debt? No, researchers say
Insufficient sleep and untreated sleep disorders put people at increased risk for metabolic problems, including obesity and diabetes.
Kicking, yelling during sleep? Study finds risk factors for violent sleep disorder
Taking antidepressants for depression, having post-traumatic stress disorder or anxiety diagnosed by a doctor are risk factors for a disruptive and sometimes violent sleep disorder called rapid eye movement (REM) sleep behavior disorder, according to a study published in the Dec.
Sleep health and yoga intervention delivered in low-income communities improves sleep
Pilot study results indicate that a sleep and yoga intervention has promising effects on improving sleep disturbance, sleep-related impairment, and sleep health behaviors.
Can weekend sleep make up for the detriments of sleep deprivation during the week?
In a recent Journal of Sleep Research study, short, but not long, weekend sleep was associated with an increased risk of early death in individuals under 65 years of age.
More Sleep News and Sleep Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.