Knockout of stim2a Increases Calcium Oscillations in Neurons and Induces Hyperactive-Like Phenotype in Zebrafish Larvae

Abstract

Stromal interaction molecule (STIM) proteins play a crucial role in store-operated calcium entry (SOCE) as endoplasmic reticulum Ca2+ sensors. In neurons, STIM2 was shown to have distinct functions from STIM1. However, its role in brain activity and behavior was not fully elucidated. The present study analyzed behavior in zebrafish (Danio rerio) that lacked stim2a. The mutant animals had no morphological abnormalities and were fertile. RNA-sequencing revealed alterations of the expression of transcription factor genes and several members of the calcium toolkit. Neuronal Ca2+ activity was measured in vivo in neurons that expressed the GCaMP5G sensor. Optic tectum neurons in stim2a−/− fish had more frequent Ca2+ signal oscillations compared with neurons in wildtype (WT) fish. We detected an increase in activity during the visual–motor response test, an increase in thigmotaxis in the open field test, and the disruption of phototaxis in the dark/light preference test in stim2a−/− mutants compared with WT. Both groups of animals reacted to glutamate and pentylenetetrazol with an increase in activity during the visual–motor response test, with no major differences between groups. Altogether, our results suggest that the hyperactive-like phenotype of stim2a−/− mutant zebrafish is caused by the dysregulation of Ca2+ homeostasis and signaling.

The Roles of Histamine Receptor 1 (hrh1) in Neurotransmitter System Regulation, Behavior, and Neurogenesis in Zebrafish

“…5 a). During the same trial, we also assessed thigmotaxis, a behavior in which animals tend to avoid the center of the arena and is generally associated with an anxious-like phenotype [ 24 ]. hrh1 − / − larvae and hrh1 + / + siblings did not statistically differ when the frequency and cumulative time spent in the center of the arena were measured (Fig.…”

Ap4s1 truncation leads to axonal defects in a zebrafish model of spastic paraplegia 52

“…At 4 dpf, zebrafish larvae were transferred to 24‐well plate, with a single zebrafish and 2 mL embryonic medium in each well. Spontaneous movements were recorded for 15 min at 30 fps using a camera (Point Grey, Canada) (Gupta et al, 2020). To assess pentylenetetrazole (PTZ)‐induced motor activity, PTZ stock was added to each well, and the movements were recorded immediately for 15 min.…”