[Dynamic changes of dopamine and its metabolite levels in the rat striatum after cerebral ischemia-reperfusion and electroacupuncture].

OBJECTIVE

To explore the involvement of dopamine (DA) and its metabolites in the extracellular fluid of the striatum on the resisting action of electroacupuncture (EA) for acute cerebral ischemia-reperfusion (CI/R) injury.

METHODS

A total of 50 SD male rats were randomly divided into normal control, sham-operation (sham), sham + EA, CI/R model, CI/R + EA groups. CI/R model was induced by right middle cerebral artery occlusion (MCAO) for 90 min and reperfusion for 225 min. EA (2 Hz, 3 mA, continuous waves) was applied to "Fengchi" (GB 20) for 20 min, with a 10 min rest, and given once again fo 20 min. The concentrations of DA and its metabolites [3,4- dihydroxy-phenyl acetic acid (DOPAC) and homovanillic acid (HVA)] in the extracellular fluid of the striatum were determined by microdialysis and high performance liquid chromatography (HPLC).

RESULTS

The extracellular levels of DA, DOPAC and HVA in normal group, sham group and sham+ EA group had no significant changes during the whole study. The extracellular level of DA peaked 15-45 min after CI and 0-30 min after CI/R (P < 0.05). A rising trend was also observed 120 min following CI/R. DOPAC level peaked 15 min and 75 min after CI and 75 min after CI/R. After EA, DA level was significantly lower in EA group than that in model group 90 min after CI/R (P < 0.05), and no peak was observed again. After EA, DOPAC level maintained its basic level, and no peak was found after CI/R. The changing trend of HVA was similar to that of DOPAC, and the extracellular HVA level in EA + model group was significantly lower than that in model group 75 min after CI/R.

CONCLUSION

EA can decrease the accumulation of DA and its metabolites in the extracellular fluid of the striatum, which may contribute to its effect in preventing the brain from CI/R injury.