三磷酸腺苷（ATP）是耳蜗中一种重要的信号分子。我们的前期研究发现新生大鼠耳蜗血管纹缘细胞中存在ATP囊泡，并证实此种囊泡为胞内溶酶体，但是ATP释放的机制还未完全阐明。我们发现ATP释放与内质网钙库之间存在相互关系，因此提出缘细胞释放ATP的可能机制：细胞外ATP与细胞膜上的P2Y受体结合后产生1,4,5-三磷酸肌醇（IP3），后者与内质网IP3受体结合后促进内质网钙库中Ca2+释放，从而进一步引发溶酶体胞吐作用释放ATP。本项目拟通过缘细胞培养、免疫组化、耳蜗切片、生物发光法ATP检测、荧光分光光度计钙检测、激光共聚焦显微镜钙成像、透射电镜验证上述ATP释放机制；建立缘细胞氧糖剥夺（OGD）模型，探索缺氧状态下缘细胞是否通过自噬储存、胞吐释放ATP自我保护。本申请研究生理和缺氧状态下缘细胞的ATP释放机制，对阐明ATP在耳蜗病理生理机制中的作用有重大意义。

Adenosine triphosphate (ATP) is a crucial signal molecule in the cochlea. We found that there were ATP-containing vesicles in the cytoplasm of marginal cells in the stria vascular in neonatal rat cochlea in our previous work and proved that these vesicles were lysosomes. However, the mechanism of ATP release remains unknown. We found an interaction exists between ATP release and calcium store of the endoplasmic reticulum (ER) in marginal cells. Therefore, we propose a possible mechanism of ATP release from marginal cells: extracellular ATP activates P2Y receptors on the marginal cell to generate Ins(1,4,5)P3 (IP3) which bind to IP3 receptors, causing ER Ca2+ release, in turn increased intracellular Ca2+ subsequently causes lysosomal exocytosis to release ATP. This project is to verify the hypothesis above through cell culture, immunohistochemistry, cochlear slices technique, ATP measurement by bioluminescence, calcium detection by fluorescence spectrophotometer, calcium image under confocal laser scanning microscopy, transmission electron microscopy, and to explore whether the marginal cells can be self-preservation by autophagy and ATP release via exocytosis under hypoxia circumstance after establishment of cell oxygen glucose deprivation (OGD) model. This project investigates the mechanism of ATP release from marginal cells under physiological and hypoxia circumstances, which is of great significance to clarify the role of ATP in the pathophysiology of the cochlea.