Toll-like receptor 4 signals morphine tolerance, dependence

摘要

Opioids such as morphine have been used to treat pain for centuries. These drugs, however, induce a neuroin-flammatory response that, over time, reduces analgesia and enhances drug tolerance and dependence. Xiaohui Wang et al. (pp. 6325-6330) investigated the mechanism of this unwanted action in rodents and found that morphine causes neuroinflammation by activating an innate immune receptor, but not via classical opioid receptors as previously assumed.