The molecular mechanisms of aminergic release at “en-passent” type II synaptic terminals of the fruit fly (Drosophila melanogaster).

该建议将产生深入了解的结构和功能可塑性驱动I型和胺能II型突触终端之间的相互作用。我们特别试图了解来自II型末梢的神经调制如何影响I型末梢的快速突触囊泡释放，I型末梢也称为神经肌肉接头（NMJ）。由于它们的外周位置，这些突触很容易接近，因此，作为一个理想的例子，在不太容易接近的大脑中，突触的调制是学习过程的主要手段。与称为I型末端（或NMJ，神经肌肉接头）的运动神经元突触相比，果蝇幼虫中称为II型突触末端的神经调节神经元突触本身的研究要少得多。特别是，由酪胺能/章鱼胺能未配对正中神经元的轴突形成的II型突触末梢的胞吐作用的机制是我们实验的重点。这些II型终末形成“传递”型突触，含有致密的核心囊泡并调节NMJ的传递功效。然而，这些II型末端是否使用支架蛋白来形成活性区型细胞基质仍然未知。这个问题将通过免疫细胞化学，超微结构分析（包括免疫金标记）以及重要的超分辨率光学显微镜的组合进行严格探索，遵循Sigrist实验室建立的协议。作为一个重要的方面，更深入的了解，将寻求研究I型和II型终端之间的发展相互作用，特别是在变态，迄今未知的领域。特别是，在变态过程中，运动和神经调节神经元及其终端之间的相互作用是否是必要的，以建立功能齐全的“适当”NMJ和“en-passant”-突触（II型终端）在成人肌肉是在这里的重点。在整个过程中，我们将使用行为读出功能的重要性：（i）幼虫爬行和（ii）成人固定飞行。

The proposal will yield insights into the structural and functional plasticity driving the interplay between type I and aminergic type II synaptic terminals. We particularly seek to understand how neuromodulation emanating from type II terminals impacts on the fast synaptic vesicle release of type I terminals also known as neuromuscular junctions (NMJ).Due to their peripheral location, these synapses are easily accessible and, thus, serve as an ideal example for similar interactions in the less accessible brain where modulation of synapses is a major means for learning processes. Synapses of the neuromodulatory neurons themselves, in Drosophila larvae known as type II synaptic terminals are much less studied compared to synapses of motor neurons called type I terminals (or NMJ, neuromuscular junction). In particular, the mechanism of exocytosis of the type II synaptic terminals formed by the axons of tyraminergic/octopaminergic unpaired median neurons are in the focus of our experiments. These type II terminals form synapses of the “en-passent”-type, contain dense core vesicles and modulate the efficacy of transmission by NMJs. Whether these type II-terminals use scaffold-proteins to form active zone-type cytomatrices remains unknown, however. This question will be rigorously explored by a combination of immunocytochemistry, ultrastructural analysis including immunogold labeling and, importantly, super resolution light microscopy, following protocols well established in the Sigrist lab. As an essential aspect for deeper understanding, will seek to study the developmental interplay between of type I and II terminals, particularly during metamorphosis, so far a terra incognita. Particularly, whether interactions between motor and neuromodulatory neurons and their terminals during metamorphosis are necessary in order to establish fully functional “proper” NMJs and “en-passant”-synapses (type II terminals) in the adult muscle is in the focus here. Throughout, we shall use a behavioral read out for functional importance: (i) larval crawling and (ii) adult stationary flight.