Related topics: sleep

Do urban fish exhibit impaired sleep?

Melatonin controls the body clock—high melatonin levels make us feel tired in the evening. However, the hormone also plays an important role in animals' biological rhythms. Artificial light at night—light pollution—can ...

Shining new light on the pineal gland

When zebrafish lack a specific protein, the two hemispheres of the brain develop symmetrically, and the sleep hormone melatonin is not produced. These results were recently published by Freiburg biologists Theresa Schredelseker ...

Video: Does melatonin do anything?

Melatonin is a widely used supplement. Many people turn to the hormone hoping it will improve their sleep, but do claims of its efficacy have any merit?

Scientists discover how animals measure time of year to reproduce

Animals need to measure the time of year so that they can anticipate and adapt to the arrival of a new season to align reproduction, as well as other vital functions critical for survival. A new study, conducted at the University ...

Melatonin, biological clock keep singing fish on time

In the 1980s, people living on houseboats in the San Francisco Bay were puzzled by a droning hum of unknown origin that started abruptly in the late evening and stopped suddenly in the morning.

Animal hormone is involved in plant stress memory

Regulating melatonin production in plants via drought priming could be a promising approach to enhancing abiotic stress tolerance of crops in future climate scenarios. The findings have just been published by Journal of Pineal ...

Light at night, melatonin and bird behaviour

Low light levels, similar to those found in urban areas at night, can have a significant effect on melatonin production in birds at night. This suggests that melatonin could be mediating changes in bird behaviour at night. ...

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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