Abstract: AIM: To developa sensitive and rapid determination method of dopamine (DA)and its metabolites 3 , 4-dihydroxyphenylacetic acid (DOPAC)and homovanillic acid (HVA)in rat cerebral microdialysates.METHODS: Microdialysis probes were placed into the right stratums of Wistar rat brains and perfused with Ringer's solution at a rate of 1.5 μl·min^-1.A reverse phase HPLC with electrochemical detection (ECD)were used to assay DA , DOPAC and HVA after the cerebral microdialysates were collected every 20 minutes from awake , freely moving rats.In order to know the reliability of this method , selectivity , linear range , precision and accuracy were tested and the contents of DA , DOPAC and HVA in rat microdialysates were determined.RESULTS: The standard curve were in good linear at the range of 12.5 to 250 μg·L^-1.The recovery rates of DOPAC , DA and HVA at the concentration of 0.05 , 0.13 , 0.25μg·L^-1 were 98.33 %, 102.67 %, 92.33 % respectively.Their with-in day RSD were 3.3 %, 3.4 %, 2.5 % and between-day RSD 4.2 %, 2.3 %, 5.6 % respectively.The contents of DOPAC , DA and HVA in rat microdialysates were 1.79 ±0.07 , 0.45 ±0.02 , 1.67 ±0.05μg·ml^-1 (n =6), respectively.CONCLUSION: The simple , accurate and stable method can be applied to the study of the basic researches of diseases related to DA by cerebral microdialysis in rat.

Key words: HPLC-ECD, microdialysis, dopamine, metabolites