Selegiline of the Striatal Superoxide Dismutase

Several studies have explored SOD activity in peripheral tissues of patients with Parkinson s disease as potential markers of oxidative stress, and have yielded inconsistent results. Elevations of total (combined Cu,Zn-SOD and Mn-SOD) SOD activity and GSH peroxidase activity in serum of patients with Parkinson s disease have been reported. Furthermore, elevations of immunoreactive Mn-SOD in cerebrospinal fluid of patients with Parkinson s disease but normal levels of Cu,Zn-SOD have been detected. Erythrocyte SOD activity, which is exclusively due to Cu,Zn-SOD, is unaltered in Parkinson s disease. Moreover, no differences in mean activities of total SOD, GSH peroxidase, GSH reductase, or catalase have been detected in either the lymphocytes, granulocytes, or cerebrospinal fluid of patients with Parkinson s disease. 

L-selegiline alters the redox state of ubiquinone, suggesting that the flow of electrons is impaired in the respiratory chain. Furthermore, a decrease in ubiquinone levels has been observed, whereas ubiquinol (reduced ubiquinone) concentrations are increased in the striatum. Ubiquinol levels have been shown to augment as a result of impaired mitochondrial respiration. For example, ubiquinol concentrations were demonstrated to increase in tubular kidney cells exposed to complex IV inhibitors and in disease states with defects in respiratory chain components. These results are also consistent with the hypothesis that L-selegiline enhances 02 formation by altering the rate of electron transfer within the respiratory chain leading to increases in SOD activities in the mouse striatum. 

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