Scientists from Denmark and the US have discovered that norepinephrine plays a key role in cleaning the brain: during sleep, the brain stem releases the molecule every 50 seconds, causing blood vessels to contract and creating conditions for the removal of cellular debris, writes Science Daily.
The authors compare this process to the operation of a dishwasher at night: when you open it in the morning, the dishes will already be clean. The discovery made the scientists wonder when exactly the glymphatic system works at “maximum speed”. To answer this question, they conducted an experiment with mouse models, half of which were given a sleeping pill.
It turned out that while taking the drug, norepinephrine activity was 50% lower than during natural sleep. Despite the fact that the rodents in the sleeping pill group fell asleep faster, their cerebrospinal fluid circulation decreased by 30%. Scientists know that similar waves of norepinephrine activity are observed in humans, so the results can very accurately reflect the processes occurring in the human body.
"Many people today take sleeping pills, so they need to be aware of all the consequences in order to make informed decisions," said study co-author Natalie Hauglund.
Now scientists have a better understanding of why shallow sleep increases the risk of developing neurodegenerative diseases. In further studies, they plan to find a way to prevent these diseases at an early stage.
In another study, scientists previously found that certain areas of the brain "go quiet" during sleep, providing a kind of memory reboot.