Objective : This study was intended to investigate the analgesic effects of electroacupuncture(EA) on mechanical allodynia according to the frequency and intensity of EA. Also to know if mechanical allodynia and the analgesic effects of EA is related to the sympathetci nervous system and/or the purinergic system.
Methods : mechanical allodynia-induced rats were produced by resecting S1-S2 nerve. The zusanli(ST36) was used for acupoint and the rats were divided into 4 groups. Each group was given different stimuli[low frequency low intensity-EA(LFLI-EA), low frequency high intensity-EA(LFHI-EA), high frequency low intensity-EA(HFLI-EA), high frequency high intensity-EA(HFHI-EA)]. Futhermore, to make sympathectomy6-OHDA and pentolamie were administered intraperitonially and the concentration of norepinephrine(NE) were measured. As a ATP blocker, suramin was applied for this study.
Results : Comparing to control group, each of te 4 groups(LFLI-EA, LFHI-EA, HFLI-EA, HFHI-EA) showed a significant reduction of response frequency of mechanical allodynia. LFHI-EA was more effective than that of LFLI-EA. The LFHI-EA group also had longer lasting effects from the stimulation than the other groups.
Sympathectomy didn´t show any reduction of response frequency of mechanical allodynia(Each n=6, n=4). Nor did both sympathectomy and ATP block. The response frequency wasn´t reduced by sympathectomy or by sympathectomy and ATP block, but was significantly reduced with LFHI-EA
Conclusions : These results suggest that EA has a significant analgesic effect on mechanical allodynia which has no connection with NE and/or ATP.
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