[Toll-like receptor 4: the potential therapeutic target for neuropathic pain].

Activation of microglia plays a vital role in the initiation and maintenance of specific neuropathic pain states. By activating microglia in central nervous system, Toll-like receptor 4 (TLR4) can promote the release of proinflammatory cytokines and neuroactive compounds, participate in the initiation and maintenance of neuropathic pain, and trigger the opiate side effects. Therefore, TLR4 may be a potential therapeutic target for neuropathic pain. Inhibition of TLR4 has shown some biological effects in neuropathic pain models and ibudilast (the TLR4 pathway-inhibiting agent) has been approved for for phase 2 clinical trials. This article briefly reviews the structure, function, and mechanism of TLR4 as well as the development of TLR4-targeted drugs.