A good night of sleep entails about eight hours of blissful immobility--a state of near paralysis that, though welcome at night, would be inconvenient during the day. In a paper published in Cell Reports, scientists shed new light on the transitions between a wakeful, active state and the stillness of sleep.
Through a series of experiments in the roundworm C. elegans, the researchers show that glial cells play an unexpected role in ensuring that worms don't suddenly succumb to sleep-associated immobility. It's the latest in a growing list of functions ascribed to glial cells, which were once thought to function solely as scaffolding for neurons, but are turning out to be sophisticated biological actors in their own right.
In C. elegans, a type of glial cell known as CEPsh glia surround neurons in the worm version of a brain, and are known to wrap around select synapses, the connections between neurons. Researchers took an interest in CEPsh cells because they seemed to share many features with astrocytes, star-shaped glial cells suspected by some scientists to regulate sleep in humans and other vertebrates.
To better understand the function of CEPsh glia, the team developed a line of C. elegans that lacked these cells,then monitored the tiny worms' movements. The scientists noticed that, often, the animals abruptly stopped in place for seconds to minutes at a time--an unusual behavior for this type of worm.
"We can watch C. elegans all day when they search for food, and we rarely see them stop. The worms lacking CEPsh glia were abnormal--they looked narcoleptic," says the author.
The researchers also found that during lethargus, a sleep-like state associated with molting, C. elegans without CEPsh glia fell asleep abnormally early and stayed asleep for a longer-than-usual amount of time. Overall, worms lacking CEPsh glia appeared to possess an increased propensity for sleep.
The scientists also noticed that the modified worms matured through larval stages at a slower pace than controls. They were surprised by this outcome, which suggests that healthy development depends in part on healthy sleep patterns.
Next, the team examined the neurons whose synapses are covered with CEPsh glia. Specifically, they looked at the connection between ALA, a neuron involved in sleep, and AVE, a neuron that controls movement. They found that this synapse is inhibitory, meaning that when ALA is active, AVE can't do its job.
Researchers believe that ALA is responsible for their worms' apparent drowsiness. When they removed ALA neurons in C. elegans lacking CEPsh cells, these worms no longer displayed the odd behavior seen in previous trials: movement, sleep, and development returned to normal.
These findings suggest that, when CEPsh cells are absent, ALA inhibits AVE continuously, thereby impeding movement at inappropriate times. But CEPsh glia seem to counteract ALA neurons, permitting normal movement. "When the animal needs to be moving, the glia are important in making sure that AVE isn't listening to ALA," says the senior author.
Furthermore,researchers discovered that ALA inhibits movement without completely deactivating AVE, an usual decoupling of neuronal activity and motor output.
"We spend more than a third of our life asleep. But we don't really understand what it's good for, and we don't understand how it works," says the senior author. "In the worm, we've now shown that animals don't develop properly if sleep is messed up--and we've uncovered aspects of the underlying control processes. Given that sleep is so ubiquitous in the animal kingdom, our work may provide important general insights."
https://www.rockefeller.edu/news/22750-drowsy-worms-offer-new-insights-neuroscience-sleep/
https://www.cell.com/cell-reports/fulltext/S2211-1247(18)30217-1
Glia prevents locomotion during sleep
- 1,231 views
- Added
Edited
Latest News
TB blood test which could d…
By newseditor
Posted 27 Mar
Propionate supplementation…
By newseditor
Posted 27 Mar
Role of human Kallistatin i…
By newseditor
Posted 26 Mar
Addressing both flu and COV…
By newseditor
Posted 26 Mar
How the brain senses body p…
By newseditor
Posted 26 Mar
Other Top Stories
Omega-3 may block psychosis years later
Read more
A Liquid-to-Solid Phase Transition of the ALS Protein FUS Accelerat…
Read more
Sleep apnea and brain damage
Read more
PTSD could be prevented by blocking memory consolidation pathway!
Read more
Body fat hormone leptin influences runner's high
Read more
Protocols
All-optical presynaptic pla…
By newseditor
Posted 23 Mar
Epigenomic tomography for p…
By newseditor
Posted 20 Mar
A mouse DRG genetic toolkit…
By newseditor
Posted 17 Mar
An optogenetic method for t…
By newseditor
Posted 13 Mar
Profiling native pulmonary…
By newseditor
Posted 08 Mar
Publications
Integrated plasma proteomic…
By newseditor
Posted 27 Mar
APP antisense oligonucleoti…
By newseditor
Posted 27 Mar
Targeting Erbin-mitochondri…
By newseditor
Posted 27 Mar
Regulation of Zbp1 by miR-9…
By newseditor
Posted 27 Mar
Pain-free oral delivery of…
By newseditor
Posted 27 Mar
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar