CHRONIC TREATMENT OF AGED MICE WITH L-DEPRENYL PRODUCES MARKED STRIATAL MAO-B INHIBITION BUT NO BENEFICIAL-EFFECTS ON SURVIVAL, MOTOR-PERFORMANCE, OR NIGRAL LIPOFUSCIN ACCUMULATION

Male C57BL/6J mice were provided 1-deprenyl (at 0, 0.5 mg/kg or 1.0 mg /kg per day) in their drinking water beginning at 18 months of age. A battery of motor tests, including open-field, tightrope, rotorod, incl ined screen, runwheel, and rotodrum tests, was administered before tre atment and then 6 months later at 24 months of age. A subsample of mic e was retested again at 27 months of age. An untreated group of 9-mont h-old mice served as young controls. Deprenyl treatment reduced striat al MAO-B activity by up to 60% after 6 months on treatment but had no significant effects on striatal catecholamine levels. No significant e ffects of deprenyl treatment were observed on body weight, fluid intak e, or survival of the mice. Chronic deprenyl treatment also did not af fect motor performance in any test, except rotodrum performance at 27 months of age, which was significantly better in the 1.0 mg/kg group t reated group compared to controls. No age or deprenyl effects were obs erved with respect to cell counts in the substantia nigra. However, ni gral cells containing lipofuscin increased with age, but this neurohis tochemical parameter was also unaffected by deprenyl treatment.