Is it good or bad?
New research from the University of Copenhagen shows that the stress transmitter noradrenaline causes you to wake up several times during the night. But don’t worry. It’s part of a normal, good night’s sleep, and can even mean that you slept well.
What is Noradrenaline?
Noradrenaline is a stress hormone and transmitter, that is, involved in the body’s fight-or-flight response. It involves adrenaline and levels can go up under stress, but it also helps you focus.
“You may think of sleep as your constant state, and then you wake up. But there’s more to sleep than looking into your eyes. We already know that noradrenaline makes you wake up more than 100 times per night. . And that’s in completely normal sleep,” said assistant professor Celia Kjrby from the Center for Neural Displacement, one of the study’s first authors.
Even though noradrenaline technically causes the brain to wake up more than 100 times per night, we don’t think of it as waking up.
“Neurologically, you wake up because the brain activity in these very brief moments is the same as when you’re awake. But the moments are so brief that the sleeper won’t notice,” said Ph.D. Student Mie Andersen, is the study’s second first author.
Although the researchers studied mice, in all probability their findings could be translated to humans because they focused on underlying biological mechanisms – i.e. shared mechanisms. by all mammals.
The stress transmitter noradrenaline affects sleep waves
Professor Maiken Nedergaard, who led the study, sees the new finding as an important piece of the puzzle to understanding what happens in the brain when we sleep.
“We found the essence of the part of sleep that causes us to wake up rested, and this helps us remember what we learned the day before. We found that the refreshing part of sleep is good. is fueled by waves of noradrenaline. Very short waking times are produced by norepinephrine waves, which are also important for memory,” said Maiken Nedergaard, adding: “You could say that waking time is A nap resets the brain so it’s ready to store memory when you fall asleep.”
We will return to the topic of memory shortly.
What did the researchers do?
Microfibers made of glass and genetically controlled ‘light receptors’ were introduced into the brains of test mice. Optical fibers are attached to the cable, including the LED light source.
The researchers then measured the animals’ current and current noradrenaline levels and compared them to the electrical activity in their brains. This is where they discovered the high levels of noradrenaline.
The researchers then conducted a memory test using an implanted device to increase the amplitude of the noradrenaline waves, improving the animals’ memory.
Previous research has suggested that noradrenaline, linked to stress, is inactive during sleep. Therefore, the researchers were surprised to see how well noradrenaline worked during sleep.
New research shows that when we sleep, the level of noradrenaline in the body continuously rises and falls in an oscillating fashion. A high noradrenaline level means the brain is briefly awake, while a low noradrenaline level means you are asleep. Your noradrenaline and ‘awake’ levels are interconnected and constantly changing.
“About 30 seconds pass from ‘peak’ to ‘peak’, which means your noradrenaline levels are constantly changing. At the same time, we can tell that the deeper the ‘valley’, i.e., sleep. the better, so is the level of Mie Andersen said.
“This suggests that you probably don’t need to worry if you wake up at night. Of course, long-term sleep loss is not good, but our research shows that short-term awakening is a natural part of the situation.” nature of sleep in relation to memory, adds Celia Kjrby.
Mice develop ‘super memory’
It is a well known fact that Sleep is good for us in many ways. It removes waste products, prevents Alzheimer’s disease and improves our memory.
The latter study was also the focus of this study, and the findings showed that rats with the most deep noradrenaline valleys had the best memory.
“The mice developed ‘super memory’. They had less trouble recalling things they learned the previous day,” said Celia Kjrby. This, of course, suggests that noradrenaline motivation is enhanced. sleep affects our memory.”
First, the mice were allowed to sniff two identical objects. Then they are put to sleep, and when they wake up, they will return to the object. However, one of the two objects has been replaced with a new object. Rats that had seen the highest number of noradrenaline valleys tended to study the newer object, which indicated that they remembered seeing a different object last time.
New perspectives on the use of noradrenaline in antidepressants
Besides advancing our knowledge of the engine room of sleep, new research provides a fodder for thoughts related to antidepressants.
“Some forms of antidepressants increase noradrenaline levels in the body, increasing your risk of seeing fewer deep sleep valleys,” says Celia Kjrby. your memory”. We need to focus our attention on how different drugs that regulate the level of noradrenaline in the body affect our sleep. In the future, we should look to develop drugs that do not affect noradrenaline waves during sleep. “