Transgenerational reproductive effects of two serotonin reuptake inhibitors after acute exposure in Daphnia magna embryos

Abstract

The release of pharmaceuticals and personal care products (PPCPs) into aquatic environments has been a major concern for the health of ecosystems. Transgenerational plasticity is a potential mechanism for organisms to respond to changing environmental conditions, including climate change and environmental contaminants. The purpose of the present study was to determine the long-term transgenerational effects of an abundant freshwater zooplankton, Daphnia magna, to acute embryonic exposures of serotonin re-uptake inhibitors (SSRI - fluoxetine and sertraline). Both SSRIs have been used extensively to treat depression and anxiety disorders for decades and persist in freshwater ecosystems at physiologically relevant concentrations. Our results revealed that even short (72 h) embryonic exposures of D. magna embryos had long lasting consequences on life history and expression of 5HT related genes in the unexposed generation (F3). Moreover, we identified direct effects of SSRIs on heart rate and swimming behavior in the first generation that carried over from embryonic exposure. We also found that SSRI exposure resulted in a transient increase of ephippia formation in the F1 and F2 . Our results suggest that SSRI exposure has transgenerational consequences to the unexposed generation and potentially beyond, even at low concentration (10-100× lower than what can be found in natural ecosystems) and as a result of embryonic exposure. Because of the short reproductive period of D. magna and their integral role in aquatic food webs, these findings have population-level implications and deserve further investigation.