Behavioural and transcriptional changes in the amphipod Echinogammarus marinus exposed to two antidepressants, fluoxetine and sertraline

Abstract

In the past decade, there have been increasing concerns over the effects of pharmaceutical compounds in the aquatic environment, however very little is known about the effects of antidepressants such as the selective serotonin re-uptake inhibitors (SSRIs). Many biological functions within invertebrates are under the control of serotonin, such as reproduction, metabolism, moulting and behaviour. The effects of serotonin and fluoxetine have recently been shown to alter the behaviour of the marine amphipod, Echinogammarus marinus (Leach, 1815). The purpose of this study was to observe behavioural and transcriptional modifications in this crustacean exposed to the two most prescribed SSRIs (fluoxetine and sertraline) and to develop biomarkers of neurological endocrine disruption. The animals were exposed to both drugs at environmentally relevant concentrations from 0.001 to 1μg/L during short-term (1h and 1day) and medium-term (8 days) experiments. The movement of the amphipods was tracked using the behavioural analysis software during 12min alternating dark/light conditions. The behavioural analysis revealed a significant effect on velocity which was observed after 1h exposure to sertraline at 0.01μg/L and after 1 day exposure to fluoxetine as low as 0.001μg/L. The most predominant effect of drugs on velocity was recorded after 1 day exposure for the 0.1 and 0.01μg/L concentrations of fluoxetine and sertraline, respectively. Subsequently, the expression (in this article gene expression is taken to represent only transcription, although it is acknowledged that gene expression can also be regulated at translation, mRNA and protein stability levels) of several E. marinus neurological genes, potentially involved in the serotonin metabolic pathway or behaviour regulation, were analysed in animals exposed to various SSRIs concentrations using RT-qPCR. The expression of a tryptophan hydroxylase (Ph), a neurocan core protein (Neuc), a Rhodopsin (Rhod1) and an Arrestin (Arr) were measured following exposure to fluoxetine or sertraline for 8 days. The levels of Neuc, Rhod1 and Arr were significantly down-regulated to approximately 0.5-, 0.29- and 0.46-fold, respectively, for the lower concentrations of fluoxetine suggesting potential changes in the phototransduction pathway. The expression of Rhod1 tended to be up-regulated for the lower concentration of sertraline but not significantly. In summary, fluoxetine and sertraline have a significant impact on the behaviour and neurophysiology of this amphipod at environmentally relevant concentrations with effects observed after relatively short periods of time.

Prozac in the water: Chronic fluoxetine exposure and predation risk interact to shape behaviors in an estuarine crab

“…Estuarine and coastal organisms are exposed to whole suites of contaminants, many of which (e.g., sertraline (Effexor ® ; Bossus et al., 2014), carbamazepine (Tegretol ® ; Martin‐Diaz et al. 2009)) have known negative effects on aquatic and marine organisms (e.g., Fong & Molnar, 2008; Metcalfe et al., 2010; Meredith‐Williams et al, 2012; Gaw et al., 2014).…”

“…2009)) have known negative effects on aquatic and marine organisms (e.g., Fong & Molnar, 2008; Metcalfe et al., 2010; Meredith‐Williams et al, 2012; Gaw et al., 2014). Our study and others have assessed the effects of single pharmaceuticals on animal behavior and their potential to alter species interactions (Bossus et al., 2014; Gaworecki & Klaine, 2008; Hazelton et al., 2013; Piggott, Baldwin, Dissanayake, & Sloman, 2007). Yet, additional studies examining the effects of multiple compounds are warranted to understand interactive and cumulative effects on organisms and ecosystems (Brausch et al., 2012; Brodin et al., 2014).…”

“…In the same crab species, 120 μg/L of fluoxetine significantly altered locomotor behaviors (Mesquita, Guilhermino, & Guimaraes, 2011). Several other studies have demonstrated that fluoxetine leads to adverse physiological and behavioral outcomes in aquatic organisms that could alter their functional roles within the community (Bossus, Guler, Short, Morrison, & Ford, 2014; Chen, Zha, Yuan, & Wang, 2015; Dzieweczynski & Hebert, 2012; Munari, Marin, & Matozzo, 2014; Peters & Granek, 2016; Schultz et al., 2011). …”

Multidimensionality in host manipulation mimicked by serotonin injection

“…So far, neuropharmacological and immunocytochemical studies have evidenced the role of the serotonergic system in the modulation of phototaxis in uninfected gammarids [30] and in the reversal of phototaxis induced by P. laevis [6]. The possibility that this biogenic amine modulates other behaviours in gammarids comes from several ecotoxicological studies [31][32][33][34], and more generally from the abundant literature on crustaceans [30,35,36]. Serotonin may also be implicated in the regulation of energy balance and MR, as reported for fat storage and oxygen consumption in Caenorhabditis elegans [37], and in carbohydrate metabolism and oxygen consumption in the crustacean Daphnia magna [38].…”

Uptake, accumulation and metabolization of the antidepressant fluoxetine by Mytilus galloprovincialis

“…SSRIs affects a wide range of aquatic organisms, both vertebrate and invertebrate, but there is large variation in the sensitivity of organisms (Sumpter et al, 2014). By increasing the bioavailability of serotonin, fluoxetine has been described to disrupt the endocrine systems and many biological functions within invertebrates, such as reproduction, metabolism, moulting and behaviour (Bossus et al, 2014;Fong and Ford, 2014;Silva et al, 2015).…”