Differential impact of dose-range glyphosate on locomotor behavior, neuronal activity, glio-cerebrovascular structures, and transcript regulations in zebrafish larvae

We describe the development of the photoswitchable agonistLOGO, which activates GIRK channels in the dark and is rapidly deactivated upon exposure to long wavelength UV irradiation.LOGOcan be used to optically silence action potential firing in dissociated hippocampal neurons and exhibits activityin vivo, controlling the motility of zebrafish larvae in a light-dependent fashion.

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RGS14 modulates locomotor behavior and ERK signaling induced by environmental novelty and cocaine within discrete limbic structures

10.1101/2021.01.21.427672 ◽

2021 ◽

Author(s):

Stephanie L. Foster ◽

Daniel J. Lustberg ◽

Nicholas H. Harbin ◽

Sara N. Bramlett ◽

John R. Hepler ◽

...

Keyword(s):

Neuronal Activity ◽

Behavioral Responses ◽

Locomotor Behavior ◽

Erk Signaling ◽

The Novel ◽

Wild Type ◽

Protein Activity ◽

Novel Environment ◽

Environmental Novelty ◽

Limbic Regions

AbstractRationaleIn rodents, exposure to novel environments or psychostimulants promotes locomotor activity. Indeed, locomotor reactivity to novelty strongly predicts behavioral responses to psychostimulants in animal models of addiction. RGS14 is a plasticity restricting protein with unique functional domains that enable it to suppress ERK-dependent signaling as well as regulate G protein activity. Although recent studies show that RGS14 is expressed in multiple limbic regions implicated in psychostimulant- and novelty-induced hyperlocomotion, its function has been studied almost entirely in the context of hippocampal physiology and hippocampusdependent behaviors.ObjectiveWe sought to determine whether RGS14 modulates novelty- and psychostimulant-induced locomotion and neuronal activity.MethodsWe assessed Rgs14 knockout (RGS14 KO) mice and wild-type (WT) littermate controls using novelty-induced locomotion (NIL) and cocaine-induced locomotion (CIL) behavioral tests with subsequent quantification of c-fos and phosphorylated ERK (pERK) induction in limbic regions that express RGS14.ResultsCompared to WT controls, RGS14 KO mice exhibited attenuated locomotor responses in the NIL test, driven by avoidance of the center of the novel environment. By contrast, RGS14 KO mice demonstrated augmented peripheral locomotion in the CIL test conducted in either a familiar or novel environment. The absence of RGS14 enhanced induction of c-fos and pERK in the central amygdala and hippocampus (areas CA1 and CA2) when cocaine was administered in a novel environment.ConclusionsRGS14 regulates novelty- and psychostimulant-induced hyperlocomotion, particularly with respect to thigmotaxis. Further, our findings suggest RGS14 may reduce neuronal activity in discrete limbic subregions by inhibiting ERK-dependent signaling and transcription.

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Development of optical methods for real-time whole-brain functional imaging of zebrafish neuronal activity

10.36253/978-88-5518-070-2 ◽

2020 ◽

Author(s):

Lapo Turrini

Keyword(s):

Neuronal Activity ◽

Functional Imaging ◽

Danio Rerio ◽

Optical Methods ◽

Behavioural Responses ◽

Non Invasive ◽

Larval Zebrafish ◽

Zebrafish Larvae ◽

Available Technology ◽

The Brain

Each one of us in his life has, at least once, smelled the scent of roses, read one canto of Dante’s Commedia or listened to the sound of the sea from a shell. All of this is possible thanks to the astonishing capabilities of an organ, such as the brain, that allows us to collect and organize perceptions coming from sensory organs and to produce behavioural responses accordingly. Studying an operating brain in a non-invasive way is extremely difficult in mammals, and particularly in humans. In the last decade, a small teleost fish, zebrafish (Danio rerio), has been making its way into the field of neurosciences. The brain of a larval zebrafish is made up of 'only' 100000 neurons and it’s completely transparent, making it possible to optically access it. Here, taking advantage of the best of currently available technology, we devised optical solutions to investigate the dynamics of neuronal activity throughout the entire brain of zebrafish larvae.

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Whole brain functional recordings at cellular resolution in zebrafish larvae with 3D scanning multiphoton microscopy

Scientific Reports ◽

10.1038/s41598-021-90335-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Matteo Bruzzone ◽

Enrico Chiarello ◽

Marco Albanesi ◽

Maria Elena Miletto Petrazzini ◽

Aram Megighian ◽

...

Keyword(s):

Neuronal Activity ◽

Multiphoton Microscopy ◽

Cell Activity ◽

Cell Segmentation ◽

Model Organisms ◽

Structured Illumination ◽

Functional Responses ◽

Whole Brain ◽

Zebrafish Larvae ◽

Cellular Resolution

AbstractOptical recordings of neuronal activity at cellular resolution represent an invaluable tool to investigate brain mechanisms. Zebrafish larvae is one of the few model organisms where, using fluorescence-based reporters of the cell activity, it is possible to optically reconstruct the neuronal dynamics across the whole brain. Typically, leveraging the reduced light scattering, methods like lightsheet, structured illumination, and light-field microscopy use spatially extended excitation profiles to detect in parallel activity signals from multiple cells. Here, we present an alternative design for whole brain imaging based on sequential 3D point-scanning excitation. Our approach relies on a multiphoton microscope integrating an electrically tunable lens. We first apply our approach, adopting the GCaMP6s activity reporter, to detect functional responses from retinal ganglion cells (RGC) arborization fields at different depths within the zebrafish larva midbrain. Then, in larvae expressing a nuclear localized GCaMP6s, we recorded whole brain activity with cellular resolution. Adopting a semi-automatic cell segmentation, this allowed reconstructing the activity from up to 52,000 individual neurons across the brain. In conclusion, this design can easily retrofit existing imaging systems and represents a compact, versatile and reliable tool to investigate neuronal activity across the larva brain at high resolution.

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