Elevation of striatal interleukin-6 and serum corticosterone contents in MPTP-treated mice

1. Changes in the content of striatal interleukins (IL-1 beta and IL-6) and serum corticosterone in relation to deterioration of the dopaminergic system induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; a dopaminergic neurotoxin; 20 mg/kg i.p., four administrations/12 h) in C57BL/6J mice were investigated. 2. Striatal dopamine, IL-1 beta, IL-6 and serum corticosterone were measured on days 1 and 7 post-MPTP. 3. Dopamine depletion was more severe on day 7 than on day 1 post-treatment. 4. Increases in IL-6 were observed on days 1 and 7 post-MPTP. The increase in striatal IL-6 content varied with the extent of dopamine depletion, although the IL-1 beta concentration remained unchanged compared with control values on days 1 and 7 post-treatment. 5. Serum corticosterone was not different from control on day 1 post-MPTP. However, marked increases in the serum corticosterone were observed on day 7 post-treatment. 6. These results suggest that changes in striatal IL-6 and serum corticosterone are closely associated with the severity of MPTP-induced dopaminergic degeneration.