Thomson, J.S. et al. J. Exp. Biol. 223, jeb224527 (2020)
In mammals, exposure to acute stress (AS) before a painful event can reduce responses to pain, whereas exposure to chronic stress (CS) results in stress-induced hyperalgesia.
Now, a team from the University of Liverpool describes the effects of stress on pain perception in zebrafish subjected to a painful procedure. In absence of stress, fin-clipped fish had a preference for the bottom of the tank, swam at slower speed and with less complex swimming patterns compared to sham fish, whereas fin-clipped fish that had been exposed to either AS or CS behaved like undisturbed fish. These findings indicate the presence of stress-induced analgesia, a phenomenon that could be a confounding factor in studies using zebrafish.