Sunday, May 29, 2011
New research is coming out on neuromelanin. The old research data from the 1980's is being proven again in the new neuroscience. Melanin pigments are derivatives of the amino acid tyrosine. Neuromelanin is a strong chelator of metals as it accumulates iron, zinc and other trace metals. In the brain, dopamine neurons of substantia nigra the complex neuromelanin-Fe is the major iron deposit. In physiological conditions neuromelanin plays a neuroprotective role by blocking iron and other toxic metals (Cu, Mn, Cr, Hg, Cd & more). A continuous, linear accumulation of neuromelanin-Fe complex is observed in substantia nigra during the entire life span, but a dramatic decrease occurs in Parkinson's Disease. Neuromelanin may provide an antioxidant mechanism for catecholamine neurons. Also, the extraneuronal neuromelanin, released by dying neurons, is neurotoxic since it activates microglia with release of toxic molecules (NO, TNF and IL-6) which can damage neurons. Drugs able to block the neuromelanin induced activation of microglia have been found and this provides a new therapeutic approach for Parkinson's disease. A possible role of phospholipid hydroperoxidase glutathione peroxidase 4 (GPX4) in protection from oxidative stress indicating a possible neuroprotective role and some findings suggest this enzyme may contribute to the production of neuromelanin.