Deep sleep plays a crucial role in cleaning waste from the brain through the glymphatic system. Specifically, norepinephrine emerged as a key molecular conductor of this process. Scientists discovered that during deep sleep, the brainstem releases waves of norepinephrine approximately every 50 seconds. This causes blood vessels to contract and create a rhythmic flow that helps flush out toxic waste products.
The research team, led by Maiken Nedergaard, found that common sleep medications might actually interfere with this cleaning process. Mice treated with zolpidem showed 50% lower norepinephrine waves and a 30% reduced fluid transport compared to naturally sleeping mice. While these findings were primarily observed in mice, researchers believe the same mechanisms likely apply to humans, as they share a similar glymphatic system with mice. Overall, the study suggests that understanding how norepinephrine drives brain cleaning could lead to better approaches for achieving restorative sleep and potentially preventing neurological disorders, such as Alzheimer’s disease.
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