XANES spectroscopy of a single neuron from a patient with Parkinson's disease.

Chemical state of transition metals such as iron in a single neuron of the substantia nigra (SN) from a patient with Parkinson's disease (PD) was studied in this paper, using autopsy midbrain specimens including SN. Parkinson's disease is one of the major neurodegenerative diseases. The excessive accumulation of iron and its chemical states in SN neurons are related to the oxidative damage leading to neuronal cell death. X-ray absorption fine structure spectroscopy (XAFS) with SR micro beam (10 microm) was used to investigate the chemical state of iron in the SN neurons. X-ray absorption near-edge structure (XANES) spectroscopy results showed that the chemical state of iron in the neuromelanin granules within SN neurons changed from ferrous (Fe2+) to ferric (Fe3+) ion in the process of neuronal degeneration.