[Mechanisms underlying opioid addiction: new progress].

The mechanisms of opioid addiction has attracted much attention of researchers around the world. In the present review, we have discussed the recent progress in the following topics. (1) Neurotransmitters participating the mechanism of opioid addiction; (2) Roles of different opioid receptors in opioid addiction; (3) Possible involvement of learning and memory in opioid addiction; (4) The intracellular signal transductive pathways after the activation of opioid receptors. Possible method of prevention and treatment of opioid addiction are also discussed.