Think of your brain as a busy city – constantly working, processing “events”, and producing waste. What if there was an essential system in the brain that helped clear out these “toxins” and prevent harmful buildup? This is exactly what the glymphatic system does. The glymphatic system is a network that utilizes perivascular channels to circulate fluid in the brain and spinal cord (CNS). Why is it important? This system works as the brain’s “waste removal system”, removing toxic proteins that form sticky plaques and can promote neurological disorders. It relies on the movement of cerebrospinal fluid (CSF) through the brain’s perivascular spaces, where it helps to flush out these metabolic waste products. While we’ve always known the glymphatic system as a vital waste clearance system, only recently has research allowed us to understand what stimulates it and pushes our brain’s waste fluid along.
In studying a mouse’s deep sleep cycle, scientists at the University of Copenhagen, Denmark found the brainstem releases norepinephrine about once every 50 seconds. Norepinephrine, both a hormone and neurotransmitter, triggers blood vessels to contract and create rhythmic pulsations in the surrounding fluid to move waste. Scientists noticed that when norepinephrine is released, there are noticeable changes in the blood volume within the brain. There is a dynamic harmony created by norepinephrine, regulating the dilation and constriction of the arteries to remove waste products. Overall, norepinephrine works as a key regulator in the brain’s cleaning system, using rhythmic waves to stimulate blood vessels, driving the flow of cerebral fluid, flushing out waste, and leading to a healthier brain state.
Does sleeping medication have any impact on your sleep quality and your overall health? Despite media speculations, the answer is yes. The researchers took their study a step further and discovered that sleep in mice that had been treated with Zolpidem, a common sleeping aid, had less norepinephrine waves in their sleep by 50%. Additionally, their fluid transport into their brain dropped by a whole 30% as opposed to the naturally sleeping mice. Zolpidem works by enhancing GABAergic activity in the brain, which is described as the dampening of neural activity and consequently inhibiting the release of norepinephrine. Reducing norepinephrine waves may contribute to impaired vascular pulsations, hindering waste clearance and therefore affecting the brain’s ability to properly dispose of metabolic waste.
For years we have been countlessly told by our parents, doctors, and even strangers about how important it is to get sleep, and at that, high quality sleep. They aren’t wrong. As previously mentioned, the brain’s waste elimination system allows for the removal of toxic proteins that build plaques and promote neurological disorders. Recent studies from USC’s Keck School of Medicine have found correlations between damage to the brain’s small blood vessels and an increase in vascular dementia. Furthermore, clinical biomarker testing has revealed that individuals with worse glymphatic system functioning performed lower on cognitive testing, strengthening the potential link between glymphatic and cognitive decline. Additional research has also provided evidence that restriction of sleep or chronic sleep deprivation in rats is affiliated with the development of Alzheimer’s disease pathologies. The accumulation of Amyloid-β (Aβ), a metabolic “waste product” present in the brain’s interstitial fluid (BIF), can be pinned as the main molecular driver for AD progression.
What can you do to improve your glymphatic system?
