Improvement of Pain Treatment in Fish
Fish represent, after rodents, the group most often used as laboratory animals in Germany. Since they, like all vertebrates, fall under the Animal Welfare Act, scientists are legally obliged to minimize the suffering of animals in animal experiments. This includes adequate pain treatment. However, reliable data on pain perception in fish are currently lacking. For example, it is currently unclear which stimuli are perceived as painful by fish and how painkillers affect the fish nervous system. Due to the differences in brain structure between mammals and fish, knowledge already gained from other animal species cannot be easily transferred to fish.
Therefore, at the Bf3R, perception of aversive stimuli is investigated using the zebrafish (Danio rerio) as a model organism. Employing genetic animal models and confocal laser microscopy, the brain activity of living fish embryos can be visualized and quantified in real time. This allows investigating whether painkillers are dosed sufficiently to work reliably.
Brain of the zebrafish
Brain activity of living fish embryos is measured via confocal laser microscopy to identify specific patterns of activity that occur during the processing of a pain stimulus. The image visualized the neurons in the brain of a five-day-old zebrafish of a transgenic line (left). From this, a three-dimensional model of the zebrafish brain was calculated (right). The fish is in dorsal view and oriented to the left. The scale corresponds to 100 µM.
Further reading:
- BfR2GO Issue 1/2020 „When in doubt, for the fish“ https://www.bfr.bund.de/cm/429/16_pain_perception_zebrafish.pdf
- Ohnesorge, N.; Heinl, C.; Lewejohann, L. Current Methods to Investigate Nociception and Pain in Zebrafish. Frontiers in Neuroscience 2021, 15, Art. 632634. https://doi.org/10.3389/fnins.2021.632634