Possible role of pineal melatonin in the mechanisms of aging

The pineal gland has captured man's attention as early in recorded history as the Greeks when philosophers considered it the "seat of the soul". Descartes, in the Middle Ages, furthered this concept naming it "esprits animaux" or, in current language, the psychic and somatic activating principle. These notions about the pineal gland were initially purely speculative and unsupported by scientific facts. However, with the development of a sound knowledge base concerning the pineal gland over the past twenty years, evidence has accumulated to suggest a pivotal role for the pineal in the 'fine tuning' and integrating of various neural and endocrine functions. The secretion of pineal melatonin has been shown to decline progressively with age. Recent hypotheses of aging have suggested that cumulative neuronal insults associated with free radical production may be associated with the process of aging. There is evidence to suggest that melatonin may protect against the age processes in part by attenuating the effects of free radical-induced neuronal damage. Other studies derived mainly from observations on pinealectomized rats also suggest that diminished melatonin secretion may be associated with acceleration of the aging process. Thus, pineal melatonin may be a natural anti-aging hormone.