[Involvement of microglia in neuropathic pain signalling]

Neuropathic pain is often a consequence of nerve injury through surgery, bone compression, diabetes or infection. This type of pain can be so severe that even light touching can be intensely painful. Unfortunately, this state is generally resistant to currently available treatments. There is abundant evidence that activated microglia are a key player for causing the pain and ATP receptors expressed in microglia have an important role to activate microglia. In this review, we summarize the role of microglia and ATP receptors in neuropathic pain signalling. The activated microglia express P2X4 after nerve injury, which can be stimulated by endogenous ATP, resulting in the release of BDNF which is one of key molecules involving in neuropathic pain. The microglia also express many molecules that were reported to be connected in the pain. Understanding the key roles of these ATP receptors in microglia may lead to new strategies for the management of intractable chronic pain.