Health

Trouble getting to sleep? Scientists say go camping

In our modern times, many of us sit up late into the night, watching TV, fiddling with our smartphones, or reading a book by lamplight. Getting up to the sound of the morning alarm isn't easy. Now, researchers reporting in ...

Medical research

Gut bacteria have own circadian clock

The circadian rhythm, or circadian clock, is an internal mechanism that drives the 24-hour cycles that tell our bodies when to sleep, wake and eat — and now, new research has found that bacteria living within the gut ...

Diabetes

Melatonin signaling is a risk factor for type 2 diabetes

A sleeping pancreas releases less insulin, but how much insulin drops each night may differ from person to person, suggests a study published May 12, 2016 in Cell Metabolism. Up to 30 percent of the population may be predisposed ...

Psychology & Psychiatry

Darkness begone! Lights ward off Nordic winter blues

Each year, Old Man Winter drops his curtain of darkness over the Nordic countries, not lifting it again until April when spring bathes the region in sunlight and nature comes back to life.

Neuroscience

Research suggests brain's melatonin may trigger sleep

If you walk into your local drug store and ask for a supplement to help you sleep, you might be directed to a bottle labeled "melatonin." The hormone supplement's use as a sleep aid is supported by anecdotal evidence and ...

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Melatonin

Melatonin i/ˌmɛləˈtoʊnɪn/, also known chemically as N-acetyl-5-methoxytryptamine, is a naturally occurring compound found in animals, plants, and microbes. In animals, circulating levels of the hormone melatonin vary in a daily cycle, thereby allowing the entrainment of the circadian rhythms of several biological functions.

Many biological effects of melatonin are produced through activation of melatonin receptors, while others are due to its role as a pervasive and powerful antioxidant, with a particular role in the protection of nuclear and mitochondrial DNA.

In mammals, melatonin is secreted into the blood by the pineal gland in the brain. Known as the "hormone of darkness," it is secreted in darkness in both day-active (diurnal) and night-active (nocturnal) animals.

It may also be produced by a variety of peripheral cells such as bone marrow cells, lymphocytes, and epithelial cells. Usually, the melatonin concentration in these cells is much higher than that found in the blood, but it does not seem to be regulated by the photoperiod.

Research has shown that when bird chicks ingest melatonin-rich plant feed, such as rice, the melatonin binds to melatonin receptors in their brains. No food has been found to elevate plasma melatonin levels in humans.

Products containing melatonin have been available over-the-counter as dietary supplements in the United States since the mid-1990s. In many other countries, the over-the-counter sale of this neurohormone is not permitted or requires a prescription, and the U.S. Postal Service lists unapproved melatonin preparations among items prohibited by Germany.

This text uses material from Wikipedia, licensed under CC BY-SA