Abstract: Objective To investigate the effect of MPTP on the circadian oscillation of striatal dopamine(DA) release in C57BL/6J mice.Methods 120 C57BL/6J male mice were divided into 2 groups: MPTP group was administrated with 36 mg/(kg·d) MPTP-HCl for 5 consecutive days.Control group was treated with saline.After last injection,mice were sacrificed at six different time points during the 24 h period.The DA and serotonin(5-HT) levels in the striatum were determined by HPLC with electrochemical detection.Results DA level decreased significantly in MPTP group(P<0.05).The changes of DA levels in striatum of control mice during the 24 h period revealed a significant lower point at ZT16(1:30 am) and a peak at ZT0(8:30 am).MPTP group showed the same circadian oscillation.There was no circadian oscillation of 5-HT levels in both groups.Conclusion MPTP did not affect the circadian oscillation of DA release,indicating the lack of interaction between DA decrease and circadian oscillation of DA release.

Key words: MPTP, dopamine, circadian oscillation