肠易激综合征（IBS）内脏痛严重影响人们工作和生活质量，肠神经系统中肠神经元异常激活对IBS内脏痛-外周致敏有非常重要的作用，但相关分子机制不详。新近研究表明，肠胶质细胞（EGCs）不仅营养、支持肠神经系统，更可释放ATP，激活P2受体下游信号通路，调节神经元可塑性。我们前期研究发现P2受体亚型P2X3参与了应激诱导的IBS内脏痛，同时在结肠粘膜下神经丛表达明显增多，因此我们推测EGCs源性ATP可能激活突触间隙肠神经元P2X3受体，重塑其功能活性，促进IBS内脏痛。本课题拟采用内脏运动反射、腹壁撤退反射、Western blot、免疫荧光标记、荧光素酶法和全细胞膜片钳等技术，从整体-分子-细胞三个层次，观察IBS内脏痛情况下ATP/P2X3信号轴在EGCs激活肠神经元的作用及机制，揭示肠神经元功能可塑性和IBS内脏痛外周敏化的分子机制和潜在的治疗新靶标。

Visceral pain is a hallmark symptom in irritable bowel syndrome (IBS) patients that profoundly affects their daily work and quality of life. Aberrant activation of the peripheral enteric neurons in the enteric nervous system (ENS) plays essential roles in generation of visceral pain in IBS patients. However, the underlying mechanisms of visceral pain remain largely unclear. Recent studies have suggested that enteric glial cells (EGCs) not only provide structural and nutritional support for ENS, but also release abundant ATP to modulate enteric neuroplasticity via activating synaptic ionotropic P2 receptors on adjacent neurons. We have recently demonstrated that activation of P2X3 receptor mediates visceral pain in stress-induced IBS and that its expression level is increased in submucous plexus. We therefore hypothesize that ATP released by enteric glial cells could be activating synaptic P2X3 receptor on neighboring enteric neurons, thus promoting enteric functional neuroplasticity to exacerbate visceral pain in IBS patients. We intend to establish a single-prolonged stress animal model for visceral hyperalgesia. By using this model, we will examine visceromotor responses and abdominal withdrawal reflexes of the animals and use patch-clamp to study enteric neuroplasticity. We will also apply various molecular techniques such as immunofluorescence staining, western blotting and luciferase assays to critically study the molecular mechanisms underlying visceral pain in IBS. Together, our proposed studies may identify potential molecular targets for treating stress-related visceral pain in IBS patients.