Melatonin is used as a dietary supplement to promote sleep and get over jet lag, but nobody really understands how it works in the brain. Now, researchers at University of Connecticut's school of medicine, show that melatonin helps worms sleep, too, and they suspect they've identified what it does in humans.
Our bodies produce melatonin in darkness. It's technically a hormone, but you can readily buy melatonin as a supplement in pharmacies, nutrition stores, and other retail shops. It's widely used by adults and often by children as well.
Melatonin binds to melatonin receptors in the brain to produce its sleep-promoting effects. The two keyholes for melatonin are called MT1 and MT2 in human brain cells. But scientists didn't really know what happens when the keyhole is unlocked.
Now UConn Health School of Medicine neuroscientists have identified that process through their work with C. elegans worms. When melatonin fits into the MT1 receptor in the worm's brain, it opens a potassium channel known as the BK channel. The findings were published in the latest issue of the PNAS journal.
"A major function of the BK channel in neurons is to limit the release of neurotransmitters, which are chemical substances used by neurons to talk to each other, and this is what promotes sleep," said senior author Zhao-Wen Wang in a report published on the university's website.
According to Wang, the study found that worms that lack melatonin secretion, the melatonin receptor, or the BK channel spend less time in sleep, unlike the worms that have them.
The researchers' next plan is to see if the melatonin-MT1-BK relationship holds in mice.
"The BK channel is involved in all kinds of bodily happenings, from epilepsy to high blood pressure. By learning more about the relationships between the BK channel, sleep, and behavioral changes, the researchers hope both to understand melatonin better and also help people who suffer from other diseases related to the BK channel," Wang said.