Neuronal-Glia Interactions in Trigeminal Ganglia as a Basis for Future Therapy

描述（由申请人提供）：我们最近对背根神经节（DRG）中神经元索马和卫星胶质细胞（SGCs）之间的通讯进行的研究表明，响应传入神经刺激的ATP体细胞释放激活SGCs中的嘌呤能P2 X7受体（P2 X7 Rs）。在正常情况下，紧张性激活的P2 X7 Rs在SGCs减少P2 X3 R的表达在神经元胞体，从而发挥抑制性控制神经元的活动。在高频神经刺激后，P2 X7 Rs的激活引起细胞因子释放，引起胞体中P2 X3 R活性的增强和神经元兴奋性的增加。炎症和神经损伤条件下P2 X7 R介导的SGC-神经元索马反馈控制尚未得到很好的建立。这些知识对于了解异常慢性疼痛的产生和维持至关重要。该应用程序的目标是了解慢性疼痛发展的不同阶段期间神经元胞体-SGC通信的变化。我们推测，损伤后，细胞因子释放的增加开关P2 R介导的SGC-soma通信从抑制性兴奋性反馈控制，从而启动异常疼痛状态的发展。随后ATP释放的大量增加，激活P2 X7 R和泛连接蛋白-1，产生SGC-soma通信的大量增强，从而导致慢性疼痛从发展阶段过渡到维持阶段。我们将（1）确定P2 R介导的SGC-soma通讯是否在慢性疼痛的发展和维持阶段发生变化，（2）确定SGC-soma通讯变化的潜在机制，（3）确定SGC-soma通讯的调节是否是慢性疼痛管理的有效策略。

DESCRIPTION (provided by applicant): Our recent studies of the communication between neuronal soma and satellite glial cells (SGCs) in dorsal root ganglia (DRGs) suggest that somatic release of ATP in response to afferent nerve stimulation activates purinergic P2X7 receptors (P2X7Rs) in SGCs. Under normal conditions, tonic activation of P2X7Rs in SGCs reduces P2X3R expression in neuronal somata, thus exerting inhibitory control of neuronal activity. Following high frequency nerve stimulation, activation of P2X7Rs evokes cytokine release causing an enhancement of P2X3R activity in somata and an increase in the excitability of neurons. The P2X7R-mediated SGC-neuronal soma feedback controls under inflammation and nerve injury conditions have not been well established. This knowledge is essential for understanding the generation and maintenance of abnormal chronic pain. The goal of this application is to understand changes in neuronal soma-SGC communication during different phases of chronic pain development. We hypothesize that following injury, an increase in cytokine release switches P2Rmediated SGC-soma communication from inhibitory to excitatory feedback control, thus initiating the development of abnormal pain states. A subsequent large increase in ATP release, which activates P2X7Rs and pannexin-1, produces a large enhancement of SGC-soma communication and thus leads to the transition from the development to the maintenance phase of chronic pain. We will (1) determine if P2R-mediated SGC-soma communication changes during the development and maintenance phase of chronic pain, (2) determine the mechanisms underlying the change in SGC-soma communication and (3) determine if modulation of SGC-soma communication is a valid strategy for the management of chronic pain.