Neuromelanin

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Neuromelanin is a black-brownish insoluble and granular pigment , chemically an organic polymer . It is present in the human brain , as well as in the brains of other primates , but also in carnivores , horses and some amphibian species .

Neuromelanin is produced by the oxidation of cytosolic catecholamines , for example dopamine , adrenaline, noradrenaline and occurs in humans mainly in the substantia nigra , an area of ​​the midbrain , and in the locus caeruleus of the brain stem .

The neuromelanins essentially consist of linked catecholamine units. In organisms, the neuromelanins are linked to proteins. Many structural details have been found over the past 50 years. A good historical overview, as well as the state of knowledge, can be found in one of the standard works on melanogenesis. The function of neuromelanin is still the subject of controversial discussion. As far as we know today, this type of melanin appears to have protective, antioxidant properties in the brain . If divalent transition metals are also present - especially iron and copper in higher concentrations - neuromelanin seems to favor the production of reactive hydroxyl radicals or other oxygen radicals and through this toxicity contribute to the development of neurodegenerative diseases . Among other things, this would explain the decrease in pigment concentration in the brain in people who suffer from Parkinson's disease .

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  1. ↑ M. Gerlach, AX Trautwein, L. Zecca, MBH Youdim, P. Riederer: Mössbauer Spectroscopic Studies of Purified Human Neuromelanin Isolated from the Substantia Nigra . In: Journal of Neurochemistry . tape 65 , no. 2 , November 23, 2002, p. 923–926 , doi : 10.1046 / j.1471-4159.1995.65020923.x ( wiley.com [accessed October 14, 2019]).
  2. ↑ G. Prota: Melanins and Melanogenesis, Academic Press . 1992.
  3. ^ D Berg, M. Gerlach, MBH Youdim, KL Double, L. Zecca: Brain iron pathways and their relevance to Parkinson's disease: Brain iron pathways and Parkinson's disease . In: Journal of Neurochemistry . tape 79 , no. 2 , July 7, 2008, p. 225–236 , doi : 10.1046 / j.1471-4159.2001.00608.x ( wiley.com [accessed October 14, 2019]).