Abstract (eng)
In today's neuroscience, the brain is mostly seen as an integrative organ that processes information perceived by peripheral sensory organs. However, besides its processing function, the vertebrate brain contains many cells that have been suggested to be directly sensory. We focus on one specific type of such sensory-neurosecretory cells. These cells express the presumptive light-sensitive Opsin molecule and secrete the neuronal Nonapeptide hormone Vasotocin. These cells are highly conserved and present in vertebrates, as was shown for Zebrafish, as well as in invertebrate species, such as the annelid Platynereis dumerilii. Thus, they presumably already existed in Urbilateria and form the ancient core of the vertebrate brain (Tessmar-Raible, 2007).
In many species, the secretion pattern of the neuronal hormone Vasotocin correlates with reproductive cycles that are governed by exogenous light cycles. It has been suggested that this cell type acts as a conserved minimal module that controls the cycling Vasotocin hormone levels (Tessmar-Raible, 2007).
The goal of my diploma thesis is to further investigate different aspects of this system to finally come closer towards a functional characterisation of this highly conserved, sensory-neurosecretory cell type. For that I work on three different projects. First, I further characterise the Vasotocin hormonal system in Platynereis dumerilii. Second, I investigate how the expression of vasotocin is regulated in diverse vertebrate species and finally, I characterise novel presumptive light-sensitive members of a deep brain photoreceptor family in vertebrates.