Despite the fact that roughly 40% of all US Food and Drug Administration (FDA)-approved pharmacological therapeutics target G protein–coupled receptors (GPCRs), there remains a gap in our understanding of the physiologic and functional role of these receptors at the systems level. Although heterologous expression systems and in vitro assays have revealed a tremendous amount about GPCR signaling cascades, how these cascades interact across cell types, tissues, and organ systems remains obscure. Classic behavioral pharmacology experiments lack both the temporal and spatial resolution to resolve these long-standing issues. Over the past half century, there has been a concerted effort toward the development of optical tools for understanding GPCR signaling. From initial ligand uncaging approaches to more recent development of optogenetic techniques, these strategies have allowed researchers to probe longstanding questions in GPCR pharmacology both in vivo and in vitro. These tools have been employed across biologic systems and have allowed for interrogation of everything from specific intramolecular events to pharmacology at the systems level in a spatiotemporally specific manner. In this review, we present a historical perspective on the motivation behind and development of a variety of optical toolkits that have been generated to probe GPCR signaling. Here we highlight how these tools have been used in vivo to uncover the functional role of distinct populations of GPCRs and their signaling cascades at a systems level.

中文翻译：

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研究神经调节和 G 蛋白偶联受体信号转导的光学方法

尽管美国食品和药物管理局 (FDA) 批准的所有药物治疗中约有 40% 都是针对 G 蛋白偶联受体 (GPCR)，但我们对这些受体在系统中的生理和功能作用的理解仍然存在差距。等级。尽管异源表达系统和体外测定已经揭示了大量有关 GPCR 信号级联的信息，但这些级联如何在细胞类型、组织和器官系统之间相互作用仍然不清楚。经典的行为药理学实验缺乏时间和空间分辨率来解决这些长期存在的问题。在过去的半个世纪中，人们共同努力开发用于理解 GPCR 信号传导的光学工具。从最初的配体解笼方法到最近发展的光遗传学技术，这些策略使研究人员能够在体内和体外探索 GPCR 药理学中长期存在的问题。这些工具已在生物系统中得到应用，并允许以时空特定的方式在系统水平上询问从特定分子内事件到药理学的一切。在这篇综述中，我们从历史角度介绍了各种用于探测 GPCR 信号传导的光学工具包背后的动机和开发。在这里，我们重点介绍如何在体内使用这些工具来揭示不同 GPCR 群体的功能作用及其在系统水平上的信号级联。