Fluorescence Imaging of Neural Activity, Neurochemical Dynamics, and Drug-Specific Receptor Conformation with Genetically Encoded Sensors

Abstract

Recent advances in fluorescence imaging permit large-scale recording of neural activity and dynamics of neurochemical release with unprecedented resolution in behaving animals. Calcium imaging with highly optimized genetically encoded indicators provides a mesoscopic view of neural activity from genetically defined populations at cellular and subcellular resolutions. Rigorously improved voltage sensors and microscopy allow for robust spike imaging of populational neurons in various brain regions. In addition, recent protein engineering efforts in the past few years have led to the development of sensors for neurotransmitters and neuromodulators. Here, we discuss the development and applications of these genetically encoded fluorescent indicators in reporting neural activity in response to various behaviors in different biological systems as well as in drug discovery. We also report a simple model to guide sensor selection and optimization. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Fluorescence lifetime enables high-resolution analysis of neuromodulator dynamics across time and animals

“…Classical methods such as microdialysis, fast-scan cyclic voltammetry, or electrophysiology recordings of putative neurons that release neuromodulators provided great insights (Arbuthnott and Wickens, 2007; Ganesana et al, 2017; Puthongkham et al; Sabatini and Tian, 2020; Tuveson et al, 2004; Ungerstedt et al; Venton et al; Watabe-Uchida et al, 2017; Wightman, 2006), but lacked in spatial and temporal resolution suited for behavior, specific targeting to cells of interest, or selectivity. Recently, genetically encoded optical reporters of neuromodulators are transforming the field because they can be targeted to cells of interest, have the same spatial resolution as optical microscopy, and the temporal resolution is suited for animal behavior (Dong et al, 2022; Sabatini and Tian, 2020; Wu et al, 2022).…”

A New Deep‐Red to Near‐infrared Emission and Polarity Sensitive Fluorescent Probe Based on β‐Diketone‐boron Difluoride and Coumarin Derivative

“…Among them, fluorescence imaging technology is becoming one of the most important research tool using in chemistry, biology and medicine because of its high sensitivity noninvasiveness, ease-of-use, excellent temporal-spatial resolution and real-time monitoring. [8][9][10][11][12][13][14][15][16][17] This advanced technology is highly dependent on outstanding fluorescent probes. At present, many fluorescent probes are springing up, which has greatly accelerated the development of fluorescence imaging technology.…”

“…In recent years, many detection means have been developed rapidly. Among them, fluorescence imaging technology is becoming one of the most important research tool using in chemistry, biology and medicine because of its high sensitivity noninvasiveness, ease‐of‐use, excellent temporal‐spatial resolution and real‐time monitoring [8–17] . This advanced technology is highly dependent on outstanding fluorescent probes.…”

G protein‐coupled receptors cooperate to silence dopamine neurons

“…As our appreciation of the extracellular dynamics of hormones and transmitters grows with an ever-expanding kit of fluorescent sensors (Dong et al, 2022), this study serves as a great example of the power of carefully calibrated manipulations Perspective J Physiol 600.22…”

“…This is a clear reminder that the actions of GPCRs on the physiology of cells are complex and cannot be fully understood without also taking into consideration other concurrently active signalling pathways. As our appreciation of the extracellular dynamics of hormones and transmitters grows with an ever‐expanding kit of fluorescent sensors (Dong et al., 2022), this study serves as a great example of the power of carefully calibrated manipulations and of the strength of biophysical models to guide the design and interpretation of experiments aimed at revealing the physiological impact of multiple GPCRs acting simultaneously on the same cells.…”