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Development of an Anxiety Test in Zebrafish: The Light/ Dark Preference Test
Citation:
Muzzy, N., K. Britton, D. Hunter, J. Olin, K. Jarema, AND S. Padilla. Development of an Anxiety Test in Zebrafish: The Light/ Dark Preference Test. Carolinas SETAC 2024 Annual Meeting, Boone, NC, April 14 - 16, 2024. https://doi.org/10.23645/epacomptox.25757379
Impact/Purpose:
Presentation to Carolinas SETAC 2024 Annual Meeting
Description:
Anxiety may be related to chemical exposure during brain development, so there’s a need to assess anxiety after exposure to environmental chemicals. However, there is not a standard high throughput assay to assess mental health effects of exposure. There is a promising test in the literature using larval zebrafish: the light/dark preference test. Previous work has shown that larval zebrafish prefer light environments and dark environments may evoke anxiety, but there is no recommended standard protocol for the light/dark preference test. To standardize this assay[MN(1] , larval zebrafish were reared in 24 well microtiter plates at 26°C. At 6 days post-fertilization, plates were placed in a lightbox on a plexiglass base that blocked visible light on half of each well, creating light and dark zones that larvae were free to move between. The larval movement was recorded under both illuminated and unilluminated conditions and assessed based on the percent of time spent and distanced moved in each light or dark zone. Different variables (light intensity, time with light on or off, transferring fish before and after exposure) were assessed to evaluate confounding factors and create more efficient ways to test. Through all the experiments, zebrafish larvae occupied the light zone nearly 3x longer [SKK2] as compared to the dark zone. In addition, the larvae traveled about 40% further in the light zone. As expected, these differences disappeared in the unilluminated conditions, with no visible light to create the zones. These results did not change in different light intensities, but there were slight differences observed between corroborated earlier studies showing that larvae are dark aversive and appear less anxious in the light. In conclusion, the light/dark preference test in larval zebrafish appears to be a reliable assay of larval zebrafish behavior, but more work is needed to assess the impact of anxiogenic and anxiolytic compounds before [MN(3] chemical screening begins. This work does not reflect the official policy of the US EPA. [MN(1]Add in notes about evaluating different variables [SKK2]Suggest "occupied the light zone nearly 3X longer than the dark zone" [MN(3]Response to stressors
URLs/Downloads:
DOI: Development of an Anxiety Test in Zebrafish: The Light/ Dark Preference Test
MUZZY_ 35.2X48_.PDF (PDF, NA pp, 2170.16 KB, about PDF)