Melatonin: Nature's most versatile biological signal?
by
Pandi-Perumal SR, Srinivasan V, Maestroni GJ,
Cardinali DP, Poeggeler B, Hardeland R.
Comprehensive Center for Sleep Medicine,
Division of Pulmonary, Critical Care and Sleep Medicine,
Mount Sinai School of Medicine,
New York, NY 10029, USA.
pandiperumal@gmail.com
FEBS J. 2006 Jul;273(13):2813-38.

ABSTRACT

Melatonin is a ubiquitous molecule and widely distributed in nature, with functional activity occurring in unicellular organisms, plants, fungi and animals. In most vertebrates, including humans, melatonin is synthesized primarily in the pineal gland and is regulated by the environmental light/dark cycle via the suprachiasmatic nucleus. Pinealocytes function as 'neuroendocrine transducers' to secrete melatonin during the dark phase of the light/dark cycle and, consequently, melatonin is often called the 'hormone of darkness'. Melatonin is principally secreted at night and is centrally involved in sleep regulation, as well as in a number of other cyclical bodily activities. Melatonin is exclusively involved in signaling the 'time of day' and 'time of year' (hence considered to help both clock and calendar functions) to all tissues and is thus considered to be the body's chronological pacemaker or 'Zeitgeber'. Synthesis of melatonin also occurs in other areas of the body, including the retina, the gastrointestinal tract, skin, bone marrow and in lymphocytes, from which it may influence other physiological functions through paracrine signaling. Melatonin has also been extracted from the seeds and leaves of a number of plants and its concentration in some of this material is several orders of magnitude higher than its night-time plasma value in humans. Melatonin participates in diverse physiological functions. In addition to its timekeeping functions, melatonin is an effective antioxidant which scavenges free radicals and up-regulates several antioxidant enzymes. It also has a strong antiapoptotic signaling function, an effect which it exerts even during ischemia. Melatonin's cytoprotective properties have practical implications in the treatment of neurodegenerative diseases. Melatonin also has immune-enhancing and oncostatic properties. Its 'chronobiotic' properties have been shown to have value in treating various circadian rhythm sleep disorders, such as jet lag or shift-work sleep disorder. Melatonin acting as an 'internal sleep facilitator' promotes sleep, and melatonin's sleep-facilitating properties have been found to be useful for treating insomnia symptoms in elderly and depressive patients. A recently introduced melatonin analog, agomelatine, is also efficient for the treatment of major depressive disorder and bipolar affective disorder. Melatonin's role as a 'photoperiodic molecule' in seasonal reproduction has been established in photoperiodic species, although its regulatory influence in humans remains under investigation. Taken together, this evidence implicates melatonin in a broad range of effects with a significant regulatory influence over many of the body's physiological functions.

Options
Serotonin
Melatonin
Tryptophan
Agomelatine
Light therapy
Winter depression
Melatonin ligands
Circadian rhythms
Tryptophan plus fluoxetine
Melatonin, cortisol and mood
New antidepressants: agomelatine
Agomelatine (Valdoxan) and melatonergic drugs
Agomelatine (Valdoxan): efficacy and tolerance profile
Agomelatine, 5-HT2c antagonist and melatonin agonist
Agomelatine (Valdoxan, Melitor, Thymanax) to treat major depression
Agomelatine (Valdoxan) and the serotonin 5-HT2b and 5-HT2c receptors
Pathophysiology of depression: Role of sleep and the melatonergic system
Jet lag: therapeutic use of melatonin and possible application of melatonin analogs

Refs
and further reading

HOME
HedWeb
Nootropics
cocaine.wiki
Future Opioids
BLTC Research
MDMA/Ecstasy
Superhapiness?
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family