Whereas Huntington s disease is characterized by an excessive amount of dopamine, Parkinson s is conversely characterized by a lack of dopamine. This lack of dopamine results from the atrophy of the neurons if the substantia nigra. The symptoms of Parkinson s include dementia, limited and slowed emotional and voluntary movements, tremors, and a loss of postural reflexes. Movements are particularly difficult for Parkinson s patients in facial expressions and walking. Approximately 1.5 million Americans are affected by this degenerative disorder of the basal ganglia.
Mitochondrial proteins are the targets of oxidative damage due to dopamine.
A study was conducted using isolated mitochondria from the brain. The test was whether or not the products of dopamine oxidation alter the function of mitochondria. One of the products of dopamine oxidation is dopamine quinone. Dopamine quinone caused significant swelling in both brain and liver mitochondria.