What Can Worms Teach Us About Sleep?

 

The next time you curl up in your bed for a good night’s rest, you may want to think about how the worms in your yard might be sleeping. A recent study by researchers at Japan’s University of Tsukuba has used the humble worm to discover a key that may unlock the door to better sleep for human beings.

 

The nematode worm known to scientists as Caenorhabditis elegans has been a mainstay of laboratory research since the 1960s. Known as something of a model organism, this worm is very easy to breed and care for. But, more significantly, many of the genes in its DNA have functional counterparts in the DNA of humans.

 

These facts make the recent study by the University of Tsukuba incredibly noteworthy. Under the leadership of Professor Yu Hayashi, the University of Tsukuba research team published “Lessons on how to sleep: What we can learn from worms” in the May 2022 issue of iScience.

 

The researchers began with the hypothesis that the neuron ALA (a specific nerve cell in the central nervous system) plays a key role in the homeostatic regulation of sleep, both in worms and in human beings. “Our sleep is homeostatically regulated,” explains Professor Yu Hayashi. “In other words, the more we stay awake, the more we subsequently sleep…. C. elegans also exhibits alternating cycles of wake and sleep that are homeostatically regulated. Thus, we expected that studies using C. elegans might give us hints regarding the molecular and cellular mechanisms underlying the homeostatic regulation of sleep."

 

By isolating the ALA neuron in Caenorhabditis elegans, the University of Tsukuba discovered that it contained substantially more calcium ions when the worms had been awake for a prolonged period of time, and substantially less calcium ions after they have slept. Although they will have to be repeated and confirmed through additional research, these results suggest a direct correlation between the worm’s natural ability to homeostatically regulate sleep and the amount of calcium in its ALA neurons. Specifically, the buildup of calcium ions in these central nervous cells seems to play a key role in making the worm feel “sleepy.”

 

As humans, we have ALA neurons that are similar to C. elegans and a similar "sleepiness" trigger encoded in our central nervous system. This means that, despite being one of the most basic lifeforms with a nervous system, the worm can tell human beings a great deal about our own patterns of sleep and wakefulness as well as which cells regulate them and how.

 

The groundbreaking University of Tsukuba study lays the foundation for any number of forthcoming studies that will likely involve mice and other small mammals. Ultimately, the simple nematode worm may lead to a far more thorough understanding of why and how people sleep as well as new guidelines and treatments that can help people sleep better.