Acupuncture at SI5 attenuates morphine seeking behavior after extinction

► Relapse to the drug is a serious problem in the treatment of addiction. ► Acupuncture at SI5 attenuated the reinstatement of morphine seeking behavior. ► Acupuncture's suppression of relapse to the morphine is mediated, at least in part, via GABA pathway. Our previous studies have shown that acupuncture attenuates morphine self-administration and sensitization behavior as well as withdrawal signs. The present study was designed to investigate the role of acupuncture in the reinstatement of morphine seeking. Male Sprague-Dawley rats weighing 270–300g were subjected to intravenous catheterization after food training. The animals were trained to self-administer morphine (1.0mg/kg, 3weeks), followed by extinction (1week). Extinction conditions were introduced by substituting saline for morphine. The rats were then tested for reinstatement of morphine self-administration by a priming injection of morphine (0.25mg/kg). To see whether acupuncture can reduce morphine reinstatement, acupuncture was performed at SI5 or LI5 for 1min immediately before a morphine injection. To further test the involvement of gamma aminobutyric acid (GABA) receptors in acupuncture effects, GABA receptor antagonists were injected before acupuncture. In the present results, acupuncture at SI5, but not at control acupoint LI5 attenuated the reinstatement of morphine seeking behavior, which was blocked by the GABA receptor antagonists. It suggests that acupuncture can reduce the reinstatement of morphine seeking, possibly due to the mediation of GABA receptor system.