Popular Sleeping Pill May Block the Brain’s Essential Cleaning Cycle

During sleep, the brain performs a “wash and rinse” routine to clear out harmful proteins associated with neurodegenerative diseases like Alzheimer’s. However, new research has revealed that a widely used sleep aid might interfere with this critical process.

In 2012, neuroscientist Maiken Nedergaard from the University of Rochester Medical Center (URMC) identified a unique system in the brain responsible for waste removal. Known as the “glymphatic system,” it functions like a network of channels surrounding the brain’s blood vessels, through which cerebrospinal fluid (CSF) circulates, collecting and eliminating waste.

Since its discovery over a decade ago, researchers have linked the glymphatic system to the development of Parkinson’s disease and shown that it plays a key role in clearing toxic proteins during sleep, potentially preventing Alzheimer’s. A 2021 study even demonstrated that ultrasound could activate the system in Alzheimer’s patients, helping to remove amyloid and tau proteins associated with the disease.

Now, Nedergaard has conducted another study at URMC to explore how the glymphatic system operates and how zolpidem, the active ingredient in the popular sleep aid Ambien, affects its functioning.

Understanding the glymphatic system’s function

“As the brain transitions from wakefulness to sleep, the processing of external information slows down, while processes like the glymphatic system’s waste removal are activated,” Nedergaard explained. “The goal of this research was to better understand the drivers of glymphatic flow during sleep, with broad implications for understanding what makes sleep restorative.”

Operating in waves

Studying mice, Nedergaard’s team used optical imaging techniques combined with EEG and EMG monitors to observe the animals during their natural phases of wakefulness and sleep.

The researchers found that during non-REM sleep, when the brain is relatively calm, the neurotransmitter norepinephrine is released in slow waves. These waves triggered “micro-arousals,” which caused rhythmic contractions of blood vessels independent of the heart’s pumping. These contractions powered the movement of CSF through the glymphatic system, enabling its waste-clearing function.

These findings, along with what we know about the glymphatic system, provide a complete picture of the brain’s internal dynamics. The slow waves, micro-arousals, and norepinephrine were the missing pieces, said Natalie Hauglund, the study’s first author and currently a postdoctoral researcher at the University of Oxford.

The impact of Ambien

The team also investigated how zolpidem, the active ingredient in Ambien, affects the brain’s cleaning system. After administering the drug to mice, they observed that it blocked the slow waves of norepinephrine, disrupting the glymphatic system and preventing waste removal. This could result in the accumulation of toxic proteins, such as tau and amyloid, a hallmark of neurodegenerative diseases like Alzheimer’s.

The study establishes a mechanistic link between norepinephrine dynamics, vascular activity, and glymphatic clearance, advancing our understanding of sleep’s restorative functions,Nedergaard said. It also highlights the potential negative effects of certain sleep aids on brain health, emphasizing the importance of preserving natural sleep architecture for optimal brain function.

Read the original article on: New Atlas

Read more:Sleepy Weed Shows Significant Improvement in Sleep Quality