NEURON-GLIA INTERACTIONS IN TRIGEMINAL GANGLIA AS A BASIS FOR FUTURE THERAPY

描述（由申请人提供）：最近对脊髓和背根神经节中细胞因子作用的研究表明，神经元-胶质细胞相互作用在启动和维持慢性疼痛状态中很重要。如何做到这一点仍不清楚。口面复合体的疾病经常在患者中产生强烈的慢性疼痛，并导致他们的健康受到破坏性后果。这项研究的长期目标是了解三叉神经节（TG）中神经元-胶质细胞的相互作用，三叉神经节是口面区域的主要传入结构。我们的重点是了解TG神经元胞体（细胞体）释放的递质在神经元-卫星胶质细胞通讯中发挥的关键作用。我们推测TG神经元的过度放电会导致神经元胞体释放ATP。ATP激活卫星细胞并引起这些细胞释放细胞因子。细胞因子反过来使神经元胞体敏感并进一步增加它们的活性。将使用体外和体内方法来检验正反馈回路的这一假设。我们将（1）鉴定从TG的神经元胞体释放的递质（2）检查神经元和卫星细胞之间的通讯（3）确定细胞因子对P2 X和TRPV受体介导的反应的影响，（4）检测细胞因子对大鼠伤害性反应的作用，并确定使用siRNA下调神经元相关受体的可能性。神经胶质通讯，从而减轻口面伤害感受。将使用正常、发炎和神经结扎大鼠。将使用贴片移液器测量递质释放和膜电流;将使用Ca 2+染料监测细胞内Ca 2+浓度;将使用免疫细胞化学和Western分析检查P2 X和TRPV受体的表达。这些研究应该提供一个更好的了解的机制，神经胶质细胞的相互作用在TG。这些知识对于设计更好的治疗口面疼痛的方法至关重要。

DESCRIPTION (provided by applicant): Recent studies of cytokine actions in the spinal cord and dorsal root ganglia suggest that neuron-glia interactions are important in initiating and maintaining chronic pain states. How this is accomplished remains unclear. Disorders of the orofacial complex often produce intense chronic pain in patients and results in devastating consequences in their well being. The long-term goal of this research is to understand neuron-glia interactions in the trigeminal ganglion (TG), the primary afferent structure for the orofacial region. Our focus will be to understand the critical role that transmitters released from neuronal somata (cell bodies) of TGs play in neuron- satellite glial cell communication. We hypothesize that excessive firing in TG neurons elicits somatic release of ATP from neuronal somata. ATP activates satellite cells and evokes cytokine release from these cells. Cytokines in turn sensitize the neuronal somata and further increase their activity. In vitro and in vivo approaches will be used to test this hypothesis of positive feedback loop. We will (1) identify the transmitters released from neuronal somata of TGs (2) examine the communication between neuron and satellite cells (3) determine the effects of cytokines on P2X and TRPV receptor-mediated responses, (4) examine the action of cytokines on nociceptive responses in rats and determine the possibility of using siRNA to down-regulate receptors involved in neuron-glia communication and thus to relieve orofacial nociception. Normal, inflamed and nerve-ligated rats will be used. Transmitter release and membrane currents will be measured with patch pipettes; intracellular Ca2+ concentrations will be monitored with Ca2+ dyes; expression of P2X and TRPV receptors will be examined with immunocytochemistry and Western analyses. These studies should provide a better understanding of the mechanisms underlying neuron-glia interactions in TGs. The knowledge will be critical for designing better therapies for the treatment of orofacial pain.