Which mechanisms are involved in the protective actions of melatonin against oxidative stress?

The indoleamine melatonin is synthesized by the pineal gland and numerous other tissues or cells, such as gastrointestinal tract, bone marrow, some leukocytes and presumably various sites in the central nervous system. Pineal melatonin acts as a hormone, which is secreted to the circulation and, via the pineal recess, to the third ventricle. It oscillates in a circadian fashion, with a high amplitude and a characteristic nocturnal maximum. Pineal melatonin transmits the signal „darkness“ to numerous different target cells, including the circadian pacemaker, the suprachiasmatic nucleus (SCN). In this role, it rep…