Melatonin, syndrome melatonin dysfunction and its role as a sleep promoting hormone

Melatonin is a hormone secreted from the pineal gland at night. Melatonin is related with memory, and its associations with control of body posture and balance. There are neuroprotective, anti-inflammatory, pain-modulating, blood pressure-reducing, retinal, vascular, seasonal reproductive, ovarian physiology, osteoblast differentiation, anti-tumor and antioxidant effects of melatonin. The disorders in which variations in production of endogenous melatonin production were shown are as follows: Sleep disorders, Alzheimer’s disease, Parkinson’s disease, glaucoma, depression, breast cancer, prostate cancer, hepatoma, melanoma, congestive heart failure, cardiac syndrome X and sepsis, melatonin is able to cross the cell, organelles, and nuclear membranes and directly interact with intracellular molecules in the so-called non–receptor-mediated actions. In addition to that, melatonin also presents receptor-mediated actions that result from the interaction of this hormone with both membrane and nuclear receptors.