Mice sleep 6 hours less via brain cell tweak, feel alert next day
Normally, staying awake for extended time periods leads to the need for extra sleep. But researchers have just found that activating astrocyte cells in mice caused the rodents to stay awake for six hours longer than usual, with no noticeable sleep debt. The finding could help boost the productivity, safety and health of shift workers or other people who keep unusual hours.
As anyone who's ever stayed up late with a crying baby or a stress-riddled brain knows, missing shuteye makes you extra sleepy the next day. This seemingly immutable relationship between sleeplessness and tiredness has just been given a shakeup, however, by research done on mice.
The researchers out of Washington State University (WSU) focused on star-shaped brain cells known as astrocytes. For years, these non-neuronal cells were somewhat ignored by researchers as they were thought of as little more than a kind of biological binder holding the brain together. In fact, their name derives from the Latin for "starry glue."
But previous research, also from WSU, showed that the cells actually played a role in sleep through a process known as calcium signaling. In even earlier research, a team from Washington University showed that astrocytes had a role in regulating rodents' sense of time. More recent studies have linked the cells to a role in mediating exercise's effect on the brain, and controlling inflammation in the brain.
In the current study, the research team activated astrocytes in the brains of mice located in their basal forebrain, an area linked to sleep cycles and sleep need. The result was that the mice stayed awake for six hours during the time they'd normally be sleeping. Most remarkably, though, was the fact that the mice didn't show any signs of the brain fog and physical sluggishness that usually accompanies missed sleep.
“Extended wakefulness normally increases sleep time and intensity, but what we saw in this study was that despite hours of added wakefulness these mice did not differ from well-rested controls in terms of how long and how intensely they slept,” said senior author Marcos Frank. “This opens up the possibility that we might someday have interventions that could target astrocytes to mitigate the negative consequences of prolonged wakefulness.”
Such interventions, say the researchers, could help those who regularly suffer from sleep deprivation – such as those who work night shifts – to better handle the impacts of their irregular schedules.
Next, the researchers plan to conduct more rodent studies to see how astrocyte activation affects other biological functions including the immune response, learning, memory and attention.
The research has been published in The Journal of Neuroscience.