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ATP release in neuroepithelium of early embryonic retina

早期胚胎视网膜神经上皮的 ATP 释放

基本信息

批准号：
10670042
负责人：
YAMASHITA Masayuki
金额：
$ 2.43万
依托单位：
Nara Medical University (1999)Osaka University (1998)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

Adenosine triphosphate (ATP) activates P2 purinoceptors. The activation of P2 purinoceptors induces CaィイD12+ィエD1 mobilization (release of CaィイD12+ィエD1from intracellular CaィイD12+ィエD1 stores) in the early embryonic chick neural retina during the period when the retinal cells have mitotic activities. After the CaィイD12+ィエD1 mobilization the entry of extracellular CaィイD12+ィエD1 (capacitative CaィイD12+ィエD1 entry) also occurs in the embryonic retina. To investigate the role of P2 purinoceptors and CaィイD12+ィエD1 mobilization in the regulation of retinal cell proliferation, the effects of the P2 purinoceptor antagonists and of the against ATP on DNA synthesis were studied in retinal organ cultures from embryonic day 3 (E3) chick. The antagonists inhibited [ィイD13ィエD1H]-thymidine incorporation in a dose-dependent manner and ATP enhanced [ィイD13ィエD1H]-thymidine incorporation to maximally 200% of control. The release of ATP was demonstrated in the medium of retinal organ cultures. The concentration of ATP increased 25-fold within one hour of incubation and this concentration was kept for at least 24 hours. These results indicated that P2 purinoceptors activated by autocrine or paracrine release of ATP were involved in the regulation of DNA synthesis in the neural retina at early embryonic stages. Then we studied the effects of an inhibitor of the CaィイD12+ィエD1 pump of intracelluar CaィイD12+ィエD1 stores and an inhibitor of capacitative CaィイD12+ィエD1 entry on the DNA synthesis in the retinal organ cultures from E3 chicks and in dissociated cultures from E7 and E9 chick retinae. It was demonstrated that both antagonists inhibited [ィイD13ィエD1H]-thymidine incorporation in a dose-dependent manner without affecting cell viability or morphology. These results suggested the involvement of CaィイD12+ィエD1 mobilization and capacitative CaィイD12+ィエD1 entry in the regulation of DNA synthesis in the developing neural retina.

三磷酸腺苷(ATP)激活P2嘌呤受体。在鸡胚早期神经视网膜细胞有丝分裂活动期间，P2嘌呤受体的激活诱导了细胞内CaィイD12+ィエD1的动员(从细胞内的CaィイD12+ィエD1释放)。细胞外CaィイD12+ィエD1动员后，细胞外CaィイD12+ィエD1(容积性CaィイD12+ィエD1 Entry)也进入胚胎视网膜。为探讨P2嘌呤受体和CaィイD12+ィエD1动员在调节视网膜细胞增殖中的作用，研究了P2嘌呤受体拮抗剂及其拮抗剂对胚胎3日龄雏鸡视网膜器官细胞DNA合成的影响。拮抗剂以剂量依赖的方式抑制[ィイD13ィエD1H]-胸腺嘧啶核苷掺入，使[ィイD13ィエD1H]-胸腺嘧啶核苷掺入最高增加至对照的200%。视网膜器官培养上清液中可观察到ATP的释放。在孵育1小时内，ATP的浓度增加了25倍，并保持了至少24小时。这些结果表明，胚胎早期神经视网膜DNA合成的调节可能与ATP的自分泌或旁分泌释放所激活的P2嘌呤受体有关。然后，我们研究了细胞内CaィイD12+ィエD1泵的抑制剂和电容CaィイD12+ィエD1进入的抑制剂对E3鸡视网膜器官培养和E7和E9鸡视网膜分离培养中ィイ合成的影响。结果表明，两种拮抗剂均以剂量依赖的方式抑制[ィイD13ィエD1H]-胸腺嘧啶核苷的掺入，而不影响细胞的存活率和形态。这些结果提示，CaィイD12+ィエD1的动员和电容性的CaィイD12+ィエD1进入参与了发育中的神经视网膜DNA合成的调节。