A highly challenging question in neuroscience is to understand how aminergic neural circuits contribute to the planning and execution of behaviors, including the generation of olfactory memories. In this regard, electrophysiological techniques like Local Field Potential or imaging methods have been used to answer questions relevant to cell and circuit physiology in different animal models, such as the fly Drosophila melanogaster. However, these techniques do not provide information on the neurochemical identity of the circuits of interest. Different approaches including fast scan cyclic voltammetry, allow researchers to identify and quantify in a timely fashion the release of endogenous neuroactive molecules, but have been only used in in vitro Drosophila brain preparations. Here, we report a procedure to record for the first time the release of endogenous amines –dopamine, serotonin and octopamine‐ in adult fly brain in vivo, by fast scan cyclic voltammetry. As a proof of principle, we carried out recordings in the calyx region of the Mushroom Bodies, the brain area mainly associated to the generation of olfactory memories in flies. By using principal component regression in normalized training sets for in vivo recordings, we detect an increase in octopamine and serotonin levels in response to electric shock and olfactory cues respectively. This new approach allows the study of dynamic changes in amine neurotransmission that underlie complex behaviors in Drosophila and shed new light on the contribution of these amines to olfactory processing in this animal model.

中文翻译：

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果蝇大脑体内内源性胺释放的研究，以响应与厌恶嗅觉调节相关的刺激

神经科学中一个极具挑战性的问题是了解胺能神经回路如何有助于行为的规划和执行，包括嗅觉记忆的产生。在这方面，诸如局部场电位或成像方法之类的电生理技术已被用于回答与不同动物模型中的细胞和电路生理学相关的问题，例如黑腹果蝇。然而，这些技术不提供有关感兴趣电路的神经化学特性的信息。包括快速扫描循环伏安法在内的不同方法使研究人员能够及时识别和量化内源性神经活性分子的释放，但仅用于体外果蝇大脑准备。在这里，我们报告了一种程序，通过快速扫描循环伏安法首次记录体内成虫大脑中内源性胺的释放——多巴胺、血清素和章鱼胺。作为原理证明，我们在蘑菇体的花萼区域进行了记录，该区域主要与苍蝇嗅觉记忆的产生有关。通过在体内记录的归一化训练集中使用主成分回归，我们检测到章鱼胺和血清素水平分别响应电击和嗅觉提示的增加。这种新方法允许研究作为果蝇复杂行为基础的胺神经传递的动态变化并揭示了这些胺对这种动物模型中嗅觉加工的贡献。