Melatonin: Encyclopedia II - Melatonin - Medical uses of melatonin

Melatonin - Medical uses of melatonin

In recent times, melatonin has become available as a medication and a dietary supplement. Because it does not have to be prescribed and is in the public domain, there have been few clinical trials conducted to determine its effectiveness in treating diseases.

Melatonin is a powerful antioxidant that can easily cross cell membranes and the blood-brain barrier. Unlike other antioxidants, melatonin does not undergo redox cycling, the ability of a molecule to undergo reduction and oxidation repeatedly. Redox cycling may allow other antioxidants (such as vitamin C) to act as pro-oxidants, counterintuitively promoting free radical formation. Melatonin, once oxidized, cannot be reduced to its former state because it forms several stable end-products upon reacting with free radicals. Therefore, it has been referred to as a terminal (or suicidal) antioxidant. [5] Its antioxidant activity may reduce damage caused by some types of Parkinson's disease, and may increase longevity; it has been shown to increase the average life span of mice by 20% in some studies. [6] [7] [8] [9]

Additionally, when taken alone, it is an immunoregulator that enhances T cell production somewhat. When taken in conjunction with calcium, it is a very potent immunostimulator of the T cell response. Due to these immunoregulatory effects, it is used as an adjuvant in many clinical protocols; conversely, the increased immune system activity may aggravate autoimmune disorders.

Melatonin appears to have some use against insomnia, jet lag, and other types of misalignments in circadian rhythms. It has been studied for the treatment of cancer, immune disorders, cardiovascular diseases, depression, seasonal affective disorder (SAD), and sexual dysfunction; the results of most of these studies remain inconclusive. A study by Alfred J. Lewy and other researchers at OHSU found that it may ameliorate SAD and circadian misalignment, but as of 2005 it is generally considered to exacerbate both clinical depression and SAD.

Melatonin receptors appear to be important in mechanisms of learning and memory [10], and melatonin can alter electrophysiological processes associated with memory such as long-term potentiation (LTP)[11]. Melatonin has been shown to prevent the hyperphosphorylation of the tau protein. Hyperphosphorylation of tau protein can result in the formation of neurofibrillary tangles, a pathological feature seen in Alzheimer's disease). Thus, melatonin may be effective for treating Alzheimer's disease.¹

There may be other, far-reaching therapeutic uses for melatonin, such as in the treatment of various forms of cancer, HIV, and other viral diseases. [12] For instance, it has been shown that melatonin is involved in the regulation of body weight, and may be helpful in treating obesity (especially when combined with calcium). [13]

Adapted from the Wikipedia article "Medical uses of melatonin", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki