Melatonin (N-acetyl-5- methoxytryptamine) is a pineal gland hormone, synthesized from amino acid Ltryptophan. Other tissues including retina, skin, and gastrointestinal tract also synthesize it. It is secreted into the cerebrospinal fluid and circulatory system in a circadian pattern. Its production is light:dark dependent and its levels are low during the day and maximal during the hours of darkness. It plays an important role in different physiological and pathophysiological processes in the brain, which includes regulation of biological rhythms and seasonal reproduction. Its biological activity is associated with its action on melatonin receptors - ML-1 and ML-2. It has antioxidant and neuroprotective propertities and potential therapeutic role in different neurological disorders. Melatonin has been used as a sleep-promoting agent; more recently it has also been used in headache, movement disorders, neuropathic pain, and seizure disorders. In this review, some recent patents also discussed.
Department of Neurology and Ophthalmology, A-217 Clinical Center, Michigan State University, East Lansing, MI 48824, USA.