HEAVY-METALS AND THE ETIOLOGY OF PARKINSONS-DISEASE AND OTHER MOVEMENT-DISORDERS

Heavy metals, such as iron and manganese, are involved in neurologic d isease. Most often these diseases are associated with abnormal environ mental exposures or abnormal accumulations of heavy metals in the body . There is increasing recognition that heavy metals normally present i n the body also may play a role in disease pathogenesis through free r adical formation. When a part of the brain known as the basal ganglia is affected, movements become disordered. Parkinson's disease is one o f the most common movement disorders and is related to destruction of neurons in the substantia nigra pars compacta (SNpc) of the basal gang lia. The combination of high concentration of iron and the neurotransm itter, dopamine, may contribute to the selective vulnerability of the SNpc. Dopamine can auto-oxidize to produce free radicals particularly in the presence of iron and other heavy metals.