Neuromelanin-containing, catecholaminergic neurons in the human brain: ontogenetic aspects, development and aging

The present review compiles data on the development and aging ofneuromelanin (NM)-containing neurons in the central nervous system. Neuromelanin is brownish-to-black pigment that accumulates in the catecholaminergic (noradrenergic and dopaminergic) neurons and is a reliable natural marker that delineates the A1-A14 catecholaminergic groups of Dahlstrom and Fuxe in the human brain. The pigmentation of noradrenergic locus ceruleus neurons starts earlier than that of dopaminergic substantia nigra, but also a considerable individual variability is present. The pigmentation is well advanced in adolescence. The data at what age the maximal pigmentation is reached are controversial, as are the data on the cell loss in the NM-containing neuronal populations by normal aging. Thus, the participation ofNM in the pathogenesis of Parkinson`s disease remains enigmatic. Biomedical Reviews 2002; 13: 39-47.