Title :
Melatonin, the Hormone of Darkness
(Abridged version)
SCIENTIFIC ARTICLE
BY
Alina Masters, Seithikurippu R Pandi-Perumal, [...], and Samy I. McFarlane
Abstract
Melatonin is a hormone secreted by the enigmatic pineal gland in response to darkness, hence the name hormone of darkness.
It has generated a great deal of interest as a therapeutic modality for various diseases particularly sleep disorders.
***
Introduction
Shaped like a pinecone, the enigmatic pineal gland that is deeply seated in the brain has ignited the imagination of scholars and philosophers as well as spirituals from various cultures throughout generations.
It has been dubbed the “third eye” and “the seat of the soul” by René Descartes and was conceptualized as a ‘tranquilizing organ’.
Interestingly, investigators
suggested the
pineal gland,
and its hormone
product melatonin,
to be possibly
associated with
longevity and that
pineal gland
dysfunction and
eventual failure
is what initiates
the aging process.
*** ***
Melatonin Synthesis, Storage and Release
Melatonin is the only known hormone synthesized by the pineal gland and is released in response to darkness hence the name, “hormone of darkness”.
Melatonin provides a circadian and seasonal signal to the organisms in vertebrates.
Melatonin is produced from serotonin (made from tryptophan), through a cascade of enzymatic reactions (Figure 1).
***
It is important to note that “darkness” stimulates the pineal gland to secrete melatonin whereas exposure to light inhibits this mechanism.
***
Sleep disorders are also commonly associated with other comorbidities as well including dementias, chronic pain, mental illness and gastrointestinal disorders.
Unfortunately, irrespective of the high prevalence and the serious health consequences, sleep disorders often go undiagnosed and largely undertreated.
It is therefore critical to properly diagnose and treat certain types of circadian rhythm sleep disorders such as advanced sleep phase syndrome (ASPS), shift-work sleep disorder, and jetlag.
***
Melatonin, a versatile and pluripotent molecule, has been shown to have several beneficial effects above and beyond its highly celebrated property of sleep promotion (Figure 2).
***
Conclusion
Over the decades, melatonin, an ancient, ubiquitous, and a pleiotropic molecule, which was frequently used as a popular supplement by the general public and had many media hypes and frenzy as well as cult status with unjustified therapeutic claims often resulted in tight scrutiny.
***
Nevertheless, substantial research over the years in many facets of melatonin has demystified the potentials roles of melatonin, thereby exceeding the expectations in terms of protecting human health.
Collected and compiled
by
Ezhilarasan Venkatachalam Salem
Copyright :
Division of Endocrinology, Department of Medicine, SUNY Downstate Medical Center, 11203 Brooklyn, NY, USA
source :
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334454/
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