Abstract:The intensity of electroacupuncture(EA) stimulation has been shown to be one of the important factors for obtaining good analgesic effect in normal animals. In this paper,experiments were designed to explore if the intensity in terms of miliamperes plays an important role in EA-induced therapeutic effect on hyperalgesia in pethophysiological models.It was found that in rats with nerve injury or arthritis, the thermal or mechanical pain threshold measured by heat radiation or pressure- leg withdrawal reflex was significantly lowered.Two to four days after the induction of nerve injury or arthritis,electroacupuncture with strong(2-3mA) or weak(<1mA) intensity was given once every other day at ipeilateral Huantiao and Yanglinquan points or bilateral Huantiao points (50Hz,0.3ms). In two acupuncture groups, hyperalgesia was much weaker and recovered much quicker than that in the control group without any treatment. Though the instant analgesic effect induced by strong EA was more significant than that by weak EA,the therapeutic effects on hyperalgesi a in the whole experiment were not significantly different between strong and weak EA groups.It is suggested that in pethophysiological models with neuroplastical changes,weak EA(activating only large fibers) may be enoush to attenuate the hyperalgesia induced by nerve injury and arthritis. However,the instant analgesic effect induced by strong EA may still be useful for suppressing acute pain syndroms.