Edited by Doctor Alessio Dini
Melatonin: What it is
Melatonin (N-Acetyl-5-hydroxytryptamine) is a hormone secreted mainly by the epiphysis or pineal gland, a small endocrine gland located at the base of our brain.
Melatonin is an "amine derived from the neurotransmitter serotonin and is synthesized by pinealocytes from tryptophan (amino acid).
The secretion of melatonin is influenced by exposure to sunlight: when the light stimulus reaches the retina, a signal is transmitted to the epiphysis and its secretion is inhibited. The dark, on the other hand, stimulates its release. In fact, it is known that plasma concentrations of melatonin during the night are 3 to 10 times higher than those recorded during the day.
Functions
The main function of melatonin is to provide the body with information on the duration of day and night, acting as a light transducer; it is defined as a sort of "biological clock", which allows our body to adapt to the surrounding environment.
Melatonin has a sedative effect: the increase in its blood concentration is a signal that informs the body that it is dark and that therefore it is time to sleep and rest.
Its nocturnal production is therefore fundamental for the regulation of the sleep-wake cycle.
Melatonin also has important antioxidant properties, in the laboratory it has been demonstrated an "action on the deleterious effects of free radicals; it also increases the cytotoxic action of NK cells (natural killer cells), fundamental in the immune defense, therefore it stimulates our immune system. .
Integration of melatonin
Melatonin production decreases with age due to calcification of the epiphysis; the elderly have much lower serum values than those of young people, and this may be one of the causes of the frequent sleep disturbances they report.
The intake of melatonin can be useful in subjects suffering from insomnia, who have difficulty falling asleep or interrupting sleep; it is also widely used to alleviate the symptoms of jet-lag (a disturbance of the time zone often reported by intercontinental travelers ).
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