High rate of relapse to drug using behavior after long period of abstinence cha racterizes the behavior of experienced users of heroin and other drugs of abuse

and the relapse remains the primary problem for treatment. In the present study we built a putative animal model that mimic human relapse i.e.

the reinstatement o f morph ine induced conditioned place preference (CPP) in rats. In this study

we found electroacupuncture (EA) with low frequency (2 and 2/100 Hz) could inhibit drug priming or footshock induced CPP reinstatement in rats whe n it was given 18 hours before reinstatement

and these effects were found to be naloxone reversible

suggesting a mechanism involving the activation of opioid receptors by endogenous opioid ligands; while EA with high frequency (100 Hz) h ad no effect. Pr evious studies in our lab have amply shown that low frequency (2 Hz) stimulation could increase the release of enkephalin which acts on μ and δ opioid recepto rs up the spinal level

while high frequency (100 Hz) stimulation could increase the release of dynorphin which interacts with κ opioid receptor at spinal leve l. So we concluded the effect of EA with low frequency on relapse involving a me chanism of the activation of opioid receptors by endogenous opioid ligands above the spinal level. And we suggest that EA may be used as a putative measure for the prevention of relapse to drug use in humans.