Peter MorganNeuroscience Symposium
The Neuroscience Symposia are organized weekly by the Netherlands Institute for Neuroscience. The presentations are given by researchers from the institute or by guest speakers. The title and content of the symposium is usually made known in the week prior to the presentation.
Guest speaker Dries Kalsbeek
Colloquium room – Netherlands Institute for Neuroscience
4:00 pm – A unifying hypothesis for seasonal control of body weight and reproduction
4:45 pm – Discussion and drinks
Seasonal animals exhibit dramatic and remarkable changes in food intake and body weight as a natural part of their life-course. Such animals offer novel perspectives on the neuroendocrine control of energy balance relative to more traditionally used laboratory mice. Seasonal regulation of energy balance involves a neuroendocrine timing system to define time of year (photoperiod) as well as hypothalamic pathways controlling energy balance. To define the molecular basis of this seasonal timing-energy balance system we used transcriptomics to identify the core genes and pathways in the hypothalamus involved. This identified thyroid hormone, retinoic acid and wnt/β-catenin signaling as well as some cellular structural genes as the main molecular components. Our studies show how each of these signaling pathways and the cell structural components are strongly regulated by photoperiod and how they interact. However, recent work suggests that the way the seasonal timing system interacts with the energy balance system is not by direct drive, rather it involves interacting cycles of thyroid hormone and retinoic acid synthesis and degradation with neurogenesis and neurodegeneration occurring in the tanycytes and ependymal cells of the hypothalamus. This provides a new and potentially unifying model for the seasonal control of energy balance in mammals, which may explain the variation in responses across different species. It may also provide a model which can be applied to the seasonal control of reproduction.