Die circannuale Uhr, ihre Lokalisation und Synchronisation

• Applicant: Dr. Stefanie Monecke
• Subject Area: Animal Physiology and Biochemistry
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 26682976

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.

• DFG Programme: Research Fellowships
• International Connection: France
• Host: Professor Dr. Paul Pévet