Récepteurs purinergiques P2X et douleurs chroniques

Actions of extracellular ATP are mediated by two purinergic receptors families that are expressed at the cellular surface: the G protein coupled receptor (called P2Y) and the channel receptors (called P2X). For a few years only and through their molecular identification, the characterization of their physiological roles knows an important rise. It appears that among others, they are involved in motor, behavior and sensory modalities. Among the seven subunits, the P2X4 subunit is a key element in the mechanisms underlying the development and the maintenance of acute and chronic pains. Its activation in resident macrophages induces the release of prostaglandin E2 during peripheral inflammation. After induction of neuropathic pain, P2X4 receptors are expressed de novo by activated microglia in the spinal cord and is responsible for BDNF release. Thus, these receptors via their expression in immune cells and their roles in the release of pro-inflammatory molecules are directly involved in the modifications of the network excitability and consequently in the development of the hypersensitivity underlying pathological pains.