HIGH-DOSE SELEGILINE AUGMENTS STRIATAL UBIQUINOL IN MOUSE - AN INDICATION OF DECREASED OXIDATIVE STRESS OR OF INTERFERENCE WITH MITOCHONDRIAL RESPIRATION - A PILOT-STUDY

The effects of unspecific doses of the irreversible monoamine oxidase inhibitor selegiline on alpha-tocopherol, alpha-tocopherolquinone, ubi quinol and ubiquinone were studied in frontal cortex, hippocampus and striatum of male C57BL/6 mice 4h and 96h after a single or six injecti ons of selegiline (100mg/kg body weight, i.p.), respectively. Inhibiti on of monoamine oxidase was confirmed by activity measurements of its isoforms A and B in brain stem nuclei and striatum as well as by deter mination of striatal levels of dopamine and its major metabolites 3,4- dihydroxyphenylacetic acid and homovanillic acid. In general, levels o f alpha-tocopherol were not altered and levels of alpha-tocopherolquin one were below the detection limit. However, 96h following selegiline, levels of ubiquinols 9 and 10 were significantly increased, whereas l evels of ubiquinones 9 and 10 concomitantly decreased in the striatum. Concentrations of ubiquinols and ubiquinones in frontal cortex and hi ppocampus were unchanged 96 h following selegiline. These data suggest that selegiline affects the striatal redox ratio of ubiquinol to ubiq uinone which is important for cellular antioxidant defense and mitocho ndrial electron transfer.