A team of scientists was able to determine how stress stimulates brain cells at the wrong time during the stages of sleep, causing interrupted sleep and lack of rest, according to what was published by the “New Atlas” website, citing the “Current Biology” journal.
By investigating the physiological effect of stress on sleep in a mouse model, University of Pennsylvania scientists monitored activity in the preoptic area (POA) of the hypothalamus during normal sleep, and discovered that VGLUT2 neurons are more active during wakefulness and less active during sleep. Activity in non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep, according to what was published by Al Arabiya.net.
The website stated that non-rapid eye movement sleep constitutes three stages of the 90-minute sleep cycle, with the rapid eye movement stage being the fourth stage.
Each stage contains a cache of coordinated brain and body functions that are essential for health and memory.
But stress can cause VGLUT2 to fire during NREM phases, when it would normally be subdued, causing “microexcitations” that disturb the regular cycle. When the scientists stimulated the neurons, there was an increase in this subtle excitation.
While lack of sleep affects memory, immune function, emotional regulation and appetite, it is increasingly linked to an increased risk of disease and mental health problems.
“When you have a bad night of sleep, you notice that your memory isn’t as good as it usually is, or that your emotions are all mixed up all over the place — but a bad night of sleep disrupts many other processes,” said lead researcher Xinghai Zhong, an assistant professor of neuroscience at the University of Pennsylvania. “All over your body,” he said, adding that “this matter increases in individuals who suffer from stress-related sleep disorders.”
The researchers believe that the new discovery may not solve the root cause of the problem, which is specifically stress, but it does reveal that there is huge potential in the ability to target VGLUT2 regulation in order to suppress this subtle excitation. Researchers believe it is especially important for people who suffer from sleep disorders or other conditions such as anxiety and post-traumatic stress disorder (PTSD).
Chung added, “It is important to understand the biological factors that drive brain activity in these crucial stages of sleep, and how stimuli such as stress can disrupt it, so that we can one day develop treatments to help individuals get more restful sleep that allows their brain to complete these important processes.” ».
The researchers also discovered that when they inhibited the VGLUT2 neurons, subtle arousal during NREM sleep also decreased. Restorative NREM sleep periods became longer.
The first researcher, Jennifer Smith, said, “Glutamatergic neurons in the hypothalamus give us a promising target for developing treatments for stress-related sleep disorders,” noting that “the ability to reduce interruptions during important stages of non-REM sleep by suppressing VGLUT2 activity.” “It will be groundbreaking for individuals who suffer from sleep disturbance due to disorders such as insomnia or post-traumatic stress disorder.”
