With sleep disorders becoming increasingly common, it is no surprise that a growing number of people are taking melatonin supplements. These supplements are identical to a hormone of the same name made in our body that helps us to both fall asleep and stay asleep.
Beyond its effects on the sleep cycle, however, little is known about how melatonin works. We know that is is an antioxidant and can have far-reaching effects on cells, but not exactly how. Now, new research on how melatonin promotes sleep appears to have pinned down the exact way melatonin makes us sleepy.
The Role of Melatonin in the Human Body
Like many hormones, melatonin plays a variety of roles in the human body. It acts as an antioxidant, helping our cells to neutralize the reactive oxygen species that can accumulate from metabolic processes throughout the day. It also appears to play an important role in the cell cycle, stimulating DNA repair while we slumber at night.
However, melatonin is best known for its role in sleep. Melatonin is stored in the pineal gland of our brain. It is released after a long cascade of events that begin when our eyes stop sensing light from the environment. When it is released, we feel less alert. Our eyes begin to grow heavy. Eventually we nod off and enter sleep cycles that will continue until morning light (or alarm clocks) wake us up.
Although we know a great deal about how melatonin interacts with our bodies, we did not understand exactly how it produced these effects until a study released this month from the University of Missouri School of Medicine.
How Melatonin Promotes Sleep
Melatonin interacts with the cells in our bodies through cell receptors. One in particular, called MT1, appears to be critical to its role in sleep. Special neurons in our brains produce orexin, a hormone that helps to keep us awake. They have a set of receptors calls MT1 receptors that suppress the release of orexin when melatonin binds to them. When researchers suppressed these receptors in mice, these neurons continued to produce orexin and melatonin did not induce sleep. This indicates that these receptors play an integral part of this biochemical’s effects on sleep and alertness.
MT1 Receptors: Future Target For Insomnia Therapy?
Why does this research matter? Millions of people throughout the world suffer from insomnia and other sleep disorders, often not finding relief in the conventional over the counter and prescription therapies on the market. Many of these therapies do not work directly on melatonin production but rather act as a sedative. People who do not get the sleep they need taking melatonin supplements often try Ambien, Lunesta and other medications that induce sleep by depressing the nervous system. These can have side effects such as daytime sleepiness, sleepwalking and even hallucinations.
Knowing the exact receptors that induce sleep may be the key to creating sleep medications that work without having devastating side effects. The MT1 receptor does not appear to create effects other than suppressing orexin, so it will likely not cause a wide range of side effects to turn these MT1 receptors off.
Although we are obviously not lab mice, we share the exact same system for processing melatonin and producing orexin. Thus, we may be able to use this new information to make meaningful improvements in human health.
Sleep: The Modern Frontier
Getting enough sleep is a challenge for many people in the modern world, creating a growing need for new and better sleep medications that work well without side effects. The reasons for this need are complex: an increase in stress and anxiety likely contribute. In addition, researchers have pointed to sources of light in the environment as a potential cause of our collective loss of sleep. Even if you put away your smartphone and turn off the lamp before bed, light pollution is pervasive in most areas of the Western world.
Basic sleep hygiene can make a different for many people. Researchers recommend going to sleep at the same time and waking at the same time. In addition, keeping your bedroom for only sleep, sex and restful activities can help to train your brain to wind down as soon as you put your head on the pillow. A melatonin supplement combined with these measures can help many people to get the shut-eye they need. Even with these measures, however, there will likely be a growing need for effective sleep medications for the foreseeable future.
It is funny that a simple biochemical such as melatonin can be so little understood. However, until recently, we truly did not understand how melatonin performs its most basic function of making us sleepy. Now that we have this information, the next step is to use it to improve the sleep of the millions of people who are in desperate need.