Rapid determination of dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To determine dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection.</p><p><b>METHODS</b>Microdialysis probes were placed into the right striatum of Wistar rat brains and perfused with Ringer's solution at a rate of 1.5 microL/min. A reverse phase HPLC with electrochemistry was used to assay DA, DOPAC, and HVA after cerebral microdialysates were collected every 20 minutes from awake and freely moving rats. In order to identify the reliability of this method, its selectivity, linear range, precision and accuracy were tested and the contents of DA, DOPAC, and HVA in rat microdialysates were determined.</p><p><b>RESULTS</b>The standard curve was in good linear at the concentration ranging from 74 nmol/L to 1.5 micromol/L for DOPAC (r2=0.9996), from 66 nmol/L to 1.3 micromol/L for DA (r2=1.0000) and from 69 nmol/L to 1.4 micromol/L for HVA (r2=0.9992). The recovery of DOPAC (0.30, 0.77, 1.49 micromol/L), DA (0.26, 0.69, 1.32 micromol/L), and HVA (0.27, 0.71, 1.37 micromol/L) was 82.00+/-1.70%, 104.00+/-4.00%, 98.70+/-3.10%; 92.30+/-1.50%, 105.30+/-2.30%, 108.00+/-2.00%; 80.00+/-7.80%, 107.69+/-8.00%, and 108.66+/-3.10%, respectively at each concentration. Their intra-day RSD was 3.3%, 3.4%, and 2.5%, and inter-day RSD was 4.2%, 2.3%, and 5.6%, respectively. The mean extracellular concentrations of DOPAC, DA, and HVA in rat brain microdialysates were 10.7, 2.4, and 9.2 micromol/L (n=6), respectively.</p><p><b>CONCLUSION</b>The findings of our study suggested that the simple, accurate and stable method can be applied to basic researches of diseases related to monoamines neurotransmitters by cerebral microdialysis in rats.</p>

Effects of tetramethylpyrazine on brain oxidative damage induced by intracerebral perfusion of L-DOPA in rats with Parkinson's disease / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effects of tetramethylpyrazine (TMP) on brain oxidative damage induced by intracerebral perfusion of levodopa (L-DOPA) in rats with Parkinson's disease (PD).</p><p><b>METHODS</b>PD model rats were induced by intracerebral injection of 6-hydroxyl dopamine (6-OHDA) and perfused in brain with L-DOPA using microdialysis technique. Changes in levels of 2,3-dihydroxy benzyl acid (2.3-DHBA) and 2,5-dihydroxy benzyl acid (2,5-DHBA) in striatum of rats, formed by extracellular hydroxyl radical from salicylic acid capturing, were dynamically observed at various time points by HPLC-ED.</p><p><b>RESULTS</b>After treatment with L-DOPA, 2,3-DHBA and 2,5-DHBA in the model group showed significantly higher levels at 6 and 7 time points as compared with those in the sham-operated group at the corresponding time points (P <0.05 or P< 0.01), while these abnormal elevations were significantly inhibited in the TMP treated groups, either in large or small dose (P<0.05 or P<0.01).</p><p><b>CONCLUSION</b>TMP could reduce the L-DOPA induced brain oxidative damage in PD rats.</p>