Oxidative Stress is implicated as one of the primary factors that contribute to the development of
neurodegenerative diseases like
Alzheimer's Disease,
Parkinsonism and neurological conditions like epileptic
seizures,
stroke, brain damage, neurotrauma etc. The increased formation and release of
oxygen free radicals coupled with the rather low antioxidative potential of the central nervous system are the major reasons that account for the enhanced oxidative stress seen in neuronal cells. In addition to this, brain is also enriched with
polyunsaturated fatty acids that render neuronal cells easily vulnerable to oxidative attack. The fact that there is increased incidence of
neurodegenerative disorders in aged individuals, has prompted many investigators to search for a common factor whose progressive decline with increase in age could account for increased oxidative stress resulting in senescence and age associated degenerative diseases. Since
melatonin, the
hormone secreted from the pineal gland has a remarkable
anti-oxidant property and whose rate of production declines with increase in age, has prompted many to suggest that this
hormone plays a crucial role in the genesis of
neurodegenerative diseases.
Melatonin cannot only scavenges
oxygen free radicals like super
oxide radical (O2-),
hydroxyl radical (*
OH),
peroxyl radical (LOO*) and
peroxynitrite anion (ONOO-), but can also enhance the antioxidative potential of the cell by stimulating the synthesis of antioxidative
enzymes like super
oxide dismutase (SOD),
glutathione peroxidase (GPX), and also the
enzymes that are involved in the synthesis of
glutathione. In many instances,
melatonin increases the expression of m
RNA's of the antioxidative
enzymes.
Melatonin administration has been shown to be effective in counteracting the neurodegenerative conditions both in experimental models of
neurodegenerative diseases and in patients suffering from such diseases. A disturbance of
melatonin rhythm and secretion also has been noted in patients suffering from certain
neurodegenerative diseases. From all these, it is evident that
melatonin has a neuroprotective role.