Monitoring presynaptic release of neuropeptides in awake behaving animals

摘要 神经调节剂，如神经肽和生物胺，由神经元产生和释放，以进行相互通信。它们既可以作为神经递质，也可以作为神经调节剂，深刻影响神经回路的功能，从而调节关键的大脑功能，包括唤醒、进食、新陈代谢、社会行为、恐惧/焦虑、学习/记忆、奖励和性行为。神经调质信号转导功能障碍与许多神经和神经精神障碍有关。因此，了解大脑中神经调节功能的机制对于了解大脑疾病是很重要的。其中，神经肽是迄今为止大脑中种类最多的神经调节剂，它们参与大脑中一系列的生理、情感和认知过程。虽然已经发现了100多种神经肽及其下游受体，但神经肽功能的电路机制还没有得到充分的探索。这主要是因为该领域缺乏在动物行为时以时间上精确的方式监测神经肽释放的工具。为了填补这一空白，本文提出的研究将开发一种新的定量技术，用于检测清醒行为小鼠突触前终末的神经肽释放。这项计划将开发一种传感器，检测致密核小泡的释放，这种小泡专门包装轴突终末的神经肽。这种创新的方法将使我们能够监测基本上所有神经肽的突触前释放，从而解决关于神经肽能调节大脑功能的基本问题。

ABSTRACT Neuromodulators, such as neuropeptides and biogenic amines are produced and released by neurons to communicate with each other. They act as neurotransmitters, as well as neuromodulators, to profoundly influence the function of neural circuits, thereby regulating critical brain functions, including arousal, feeding, metabolism, social behavior, fear/anxiety, learning/memory, reward, and sexual behaviors. Dysfunction in neuromodulator signaling is associated with many neurological and neuropsychiatric disorders. Therefore, understanding the mechanism of neuromodulator functions in the brain is important for understanding brain disorders. Among these, neuropeptides are by far the most diverse class of neuromodulators in the brain, and they are involved in a range of physiological, emotional, and cognitive processes in the brain. Although more than 100 neuropeptides and their downstream receptors have been discovered, circuit-based mechanisms of neuropeptide functions have not been adequately explored. This is primarily because the field lacks tools for monitoring the release of neuropeptides in a temporally precise manner as animals perform behaviors. To fill this void, the research proposed here will develop a novel quantitative technique for detecting neuropeptide release from the presynaptic terminals in awake behaving mice. This proposal will develop a sensor that detects the release of dense-core vesicles that specifically packages neuropeptides in the axonal terminals. This innovative approach will allow us to monitor the presynaptic release of essentially all neuropeptides, thereby addressing fundamental questions about the neuropeptidergic regulation of brain functions.