Light, melatonin and the sleep-wake cycle.

Abstract

Blood levels of the pineal hormone melatonin are high at night and low during the day. Its secretion is regulated by a rhythm-generating system located in the suprachiasmatic nucleus of the hypothalamus, which is in turn regulated by light. Melatonin is regulated not only by that circadian oscillator but acts as a darkness signal, providing feedback to the oscillator. Melatonin has both a soporific effect and an ability to entrain the sleep-wake rhythm. It also has a major role in regulating the body temperature rhythm. Melatonin rhythms are altered in a variety of circadian rhythm disorders. Melatonin treatment has been reported to be effective in treatment of disorders such as jet lag and delayed sleep phase syndrome.

• Authors: G M Brown
• Journal: Journal of psychiatry & neuroscience : JPN (J Psychiatry Neurosci) Vol. 19 Issue 5 Pg. 345-53 (Nov 1994) ISSN: 1180-4882 [Print] Canada
• PMID: 7803368 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Review)

Chemical References

• Melatonin

Topics

• Body Temperature
• Circadian Rhythm
• Humans
• Hypothalamus (physiology)
• Light
• Melatonin (blood, metabolism)
• Pineal Gland (physiology)
• Sleep
• Wakefulness