Die circannuale Uhr, ihre Lokalisation und Synchronisation

本项目的目的是：1)对昼夜节律进行定位，2)探讨昼夜节律可能通过除褪黑素以外的其他途径获取光周期信息的可能性，3)野外光周期时间测量的特殊性。我的模型物种是大约一年一次的欧洲仓鼠，它的一年一次的日常活动模式的变化表现出对短光周期敏感的年度阶段。因此，在敏感期的开始和结束时，昼夜节律和周年钟相互联系，形成周年钟的大脑区域应该表现出与一年中其他时间不同的新陈代谢。为了可视化这一点，功能性磁共振成像技术将适用于欧洲仓鼠，目的是定位大约一年一次的时钟。最近的研究表明，在欧洲仓鼠中，不仅仅是褪黑素将光周期信息传递给了大约一年的时钟。为了测试这一点，切除松果体的动物将受到外来光周期的影响。同步将证明这样一条路径的存在，然后将对其进行探索。第三项研究将解决西欧欧洲仓鼠数量下降的问题，因为西欧的雌性仓鼠每年产下的小仓鼠太少，无法确保种群的连续性。这可能是由于冬眠期出现的重大延迟，因此是由于一年一次的生物钟错位所致。在室外封闭环境中，将开发记录技术来检查野外的光周期时间测量。

The aim of this project is to 1) localize the circannual clock, to investigate 2) the possibility that the circannual clock might get photoperiodic information by other pathways than melatonin and 3) the particularities of photoperiodic time measurement in the field. My model species is the circannual European hamster whose circannual driven changes in the daily activity pattern characterize an annual phase of sensitivity to short photoperiods. Thus, at the beginning and the end of the sensitive phase the circadian and the circannual clock communicate and the brain areas that form the circannual clock should show a different metabolism than at other times of year. To visualize this the functional magnetic resonance imaging technique will be adapted to European hamsters with the aim to localize the circannual clock. Recent studies suggested that in European hamsters not only melatonin mediates photoperiodic information to the circannual clock. To test this, pinealectomized animals will be subjected to an exotic photoperiodic cycle. A synchronization would prove the existence of such a pathway, which then will be explored. A third study will address the question of the decline of European hamsters in Western Europe where females have too few litters per year to ensure the continuity of the population. This might be due to a major delay in emergence from hibernacula and thus due to a misaligned circannual clock. In outdoor enclosures, recording techniques will be developed to examine photoperiodic time measurement in the field.