Echinacoside prevents the striatal extracellular levels of monoamine neurotransmitters from diminution in 6-hydroxydopamine lesion rats.

We investigated the effects of echinacoside, a phenylethanoid glycoside isolated and purified from the stems of Cistanche salsa, a Chinese herbal medicine, on the striatal extracellular levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in 6-hydroxydopamine (6-OHDA) lesion rats. Seven days after 6-OHDA was injected into the right striatum of rats, the striatal extracellular levels of DA, DOPAC and HVA fell significantly (P<0.01 vs. vehicle), as demonstrated by the method of cerebral microdialysis and high performance liquid chromatography with electrochemical detection. However, simultaneous treatment with echinacoside (7.0, 3.5mg/kg) attenuated the diminution of them (P<0.01 vs. model). The results implied that echinacoside could protect the striatal dopaminergic neurons from injury induced by 6-OHDA and may be useful in the prevention and treatment of Parkinson's disease (PD).

[Effects of tetramethylpyrazine on brain oxidative damage induced by intracerebral perfusion of L-DOPA in rats with Parkinson's disease].

OBJECTIVE: 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). METHODS: 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. RESULTS: 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). CONCLUSION: TMP could reduce the L-DOPA induced brain oxidative damage in PD rats.