Melatonin and Aging

Abstract

Disorders of sleep, cognitive impairment, and reduction in the bone density are characteristic of advancing age. Melatonin was first identified as the hormone of the pineal gland. The first-discovered role of this hormone was as a mediator of the signal “darkness” in vertebrates and the reduction of melatonin secretion observed with aging. Meanwhile, numerous additional sites of melatonin in synthesis and its multitude of functions have been identified. Melatonin is a strong antioxidant, which protects the body from numerous free radicals and active oxygen. Therefore, effects of long-term oral administration of melatonin were investigated in human and several animals. Add-on prolonged-release melatonin for 6 months had positive effects on cognitive function and sleep maintenance in Alzheimer’s disease patients. One year treatment with melatonin to postmenopausal osteopenic women increased bone mineral density at femoral neck in a dose-dependent manner. Quite recently we showed that the facilitating effect of long-term memory by melatonin in young and aged mice was attributed to AMK, which is a metabolite of melatonin in the brain. In the experiment at the International Space Station (KIBO) we obtained that melatonin suppressed microgravity-induced activated-osteoclasts in the fish scales as a bone model.