A research group from Tokyo University of Science and Kochi University has revealed that fish show high sensitivity to antidepressants intended for humans.
Human-use pharmaceuticals are not completely removed during sewage treatment and can leak into rivers and other bodies of water, potentially harming aquatic life. However, until now, it has been unclear whether pharmaceuticals developed for human use act on fish through similar molecular pathways.
This study focused on antidepressants that target human monoamine transporters (MATs). MATs play a role in taking up monoamines such as serotonin, dopamine, and norepinephrine, which function as important neurotransmitters in a wide range of animals, into cells. Antidepressants exert their effects by inhibiting the function of MATs.
Analysis of MAT genes isolated from medaka and ayu revealed that SERTa, a subtype of the fish serotonin transporter (SERT), is significantly more sensitive to antidepressants than human SERT. Furthermore, it was found that some drugs, such as mirtazapine and quetiapine, which do not target MAT in humans, exhibit inhibitory effects on fish MAT.
These results suggest that fish may be vulnerable to drugs designed for humans and could be affected through unexpected routes.
This study demonstrated that environmental risk assessments relying solely on mammalian data risk underestimating the impact on aquatic ecosystems. It is expected to provide an important scientific basis for prioritizing target pharmaceuticals in environmental monitoring programs and for developing more protective water quality guidelines.
Paper information: [Environmental Science and Technology] Characterization of fish serotonin, dopamine and norepinephrine transporters as a potential target for environmental pharmaceuticals
