An insight into the scientific background and future perspectives for the potential uses of melatonin

Melatonin is one of the most versatile and ubiquitous molecule widely distributed in nature has been reported to play a role in a wide variety of physiological responses including reproduction, circadian homeostasis, sleep, retinal neuromodulation, and vasomotor responses. 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. Melatonin is synthesized in all areas of the body such as gastrointestinal tract, skin, bone marrow, retina and in lymphocytes, from which it may influence other physiological functions through paracrine signalling. In addition to regulation of circadian rhythm of melatonin a variety of other physiological effects such as hypnotic, antidepressant, antiepileptic, oncostatic, immunomodulatory, antiosteoporotic, in cardiovascular disease, neuromodulatory and cerebral ischaemic condition have been reported. Moreover there is scarcity of literature that reviewed the scientific evidence for its use in these conditions. Therefore in this article we review recent advances in this research field, which is preceded by a concise account of general information about melatonin, melatonin receptors and intracellular signalling pathways for melatonin actions.