Parkinson disease pathological process

The pathological characteristic of Parkinson s disease is the selective degeneration of dopamine neurons in the pars compacta of the substantia nigra. The mechanism for the loss of neurons remains to be elucidated, and recently apoptosis has been proposed as a death process in Parkinson s disease. For example, the level of a product of the oxidative stress, 4-hydroxy-2-nonenal protein adduct, was found to increase in the nigral neurons of parkinsonian brains. Peroxynitrite (see Figure 13.6) has been proposed to be involved in the neuronal cell death in some neurodegenerative diseases, such as amyotrophic lateral sclerosis. 

Because of the instability of peroxynitrite under physiological conditions, the detection of 3-nitrotyrosine (NC>2-Tyr) has become a biochemical marker for the presence of peroxynitrite in pathophysiological processes. The biological significance of tyrosine nitration is a subject of great interest, because extensive evidence supports the formation of nitrotyrosine in vivo in diverse pathological conditions such as heart diseases, chronic inflammation and autoimmune diseases, cancer, Parkinson s disease, Alzheimer s disease, multiple sclerosis, amyotrophic lateral sclerosis, and ischemia-reperfusion injury [11]. 

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