Short-term exposure to tricyclic antidepressants delays righting time in marine and freshwater snails with evidence for low-dose stimulation of righting speed by imipramine

摘要

Active pharmaceutical ingredients such as tricyclic antidepressants (TCAs) are contaminants of emerging concern which are commonly detected in wastewater effluent and which can disrupt the behavior of non-target organisms. In aquatic snails, the righting response is a critical behavior that has been shown to be inhibited by exposure to SSRI-type antidepressants. We exposed marine and freshwater snails to three tricyclic antidepressants (clomipramine, amitriptyline, and imipramine) for 1h and measured righting response time. In the marine mud snail (Ilyanassa obsoleta), all three TCAs significantly increased righting time at concentrations as low as 156g/L. Similarly, in the freshwater snail Leptoxis carinata, all three TCAs increased righting time at concentrations as low as 263g/L. However, exposure to imipramine from 15.8 to 316g/L resulted in significantly faster righting time. Such low-dose stimulation and high-dose inhibition are characteristics of a hormetic response. We discuss the possible physiological mechanism of action of TCAs and other antidepressants on snail behavior, and the occurrence of non-monotonic, hormetic dose responses to human pharmaceuticals in the aquatic environment.