Reprint of "Effects of the SSRI citalopram on behaviours connected to stress and reproduction in Endler guppy, Poecilia wingei"

Personality Affects Zebrafish Response to Sertraline

Sertraline is widely prescribed to treat anxiety and depression. Sertraline acts by blocking serotonin, norepinephrine, and dopamine transporters systems and has been detected in surface waters globally, where it may impact fish behavior. We classified zebrafish personality on three behavioral axes, boldness, anxiety, and sociability, assigning fish as either high or low in each category. The fish were exposed to nominal concentrations of 0, 5, 50, 500, or 5000 ng/L sertraline (measured concentrations: <10, 21.3, 370, and 2200 ng/L, respectively) to assess changes in boldness, anxiety, and sociability after 7 and 28 days. We also measured shoaling behavior and response to an alarm cue, and determined the gut microbiome of a subset of fish. After 7 days there was no overall effect of sertraline on boldness, but there was an interaction between initial personality and sex, with a stronger impact on females classified as low-boldness personality. Sertraline reduced sociability in all treatments compared with the control, but there was again an interaction between sertraline and initial personality. Fish that were classified as low-sociability responded more strongly to sertraline. After 7 days, fish exposed to a nominal concentration of 5000 ng/L (2200 ng/L measured) showed higher anxiety than controls, with the overall pattern of initial behavior retained. After 28 days, similar patterns were observed, but with higher variation. There was only a weak association between the gut microbiome and personality. Overall, the study highlights the importance of considering initial behavior, which can affect response to pollutants. Our results may also be applicable to human studies and provide a mechanism to explain why different individuals respond differently to the drug. Environ Toxicol Chem 2024;43:132-146. © 2023 SETAC.

Effects of pharmaceutically active compounds (PhACs) on fish body and scale shape in natural waters

Background

In recent years, there are growing concerns about pharmaceutically active compounds (PhACs) in natural ecosystems. These compounds have been found in natural waters and in fish tissues worldwide. Regarding their growing distribution and abundance, it is becoming clear that traditionally used risk assessment methodologies and ecotoxicological studies have limitations in several respects. In our study a new, combined approach of environmental impact assesment of PhACs has been used.

Methods

In this study, the constant watercourses of the suburban region of the Hungarian capital (Budapest) were sampled, and the body shape and scale shape of three fish species (roach Rutilus rutilus, chub Squalius cephalus, gibel carp Carassius gibelio) found in these waters were analyzed, based on landmark-based geometric morphometric methods. Possible connections were made between the differences in body shape and scale shape, and abiotic environmental variables (local- and landscape-scale) and measured PhACs.

Results

Significant connections were found between shape and PhACs concentrations in several cases. Despite the relatively large number of compounds (54) detected, citalopram, propranolol, codeine and trimetazidine significantly affected only fish body and scale shape, based on their concentrations. These four PhACs were shown to be high (citalopram), medium (propranolol and codeine), and low (trimetazidine) risk levels during the environmental risk assessment, which were based on Risk Quotient calculation. Furthermore, seven PhACs (diclofenac, Estrone (E1), tramadol, caffeine 17α-Ethinylestradiol (EE2), 17α-Estradiol (aE2), Estriol (E3)) were also categorized with a high risk level. However, our morphological studies indicated that only citalopram was found to affect fish phenotype amongst the PhACs posing high risk. Therefore, our results revealed that the output of (traditional) environmental/ecological risk assessment based on ecotoxicological data of different aquatic organisms not necessarily show consistency with a “real-life” situation; furthermore, the morphological investigations may also be a good sub-lethal endpoint in ecotoxicological assessments.

Effects of selective serotonin reuptake inhibitor sertraline on hybrid striped bass predatory behavior and brain chemistry

Millions of pharmaceuticals are prescribed each year. Wastewater treatment plants fail to remove all pharmaceuticals from discharge leading to detectable concentrations entering aquatic ecosystems where the compounds can encounter nontarget organisms. Selective serotonin reuptake inhibitor (SSRI) class of antidepressants interact with transporters in the brain and peripheral nervous system to change serotonin levels in the synapse. Sublethal exposure to SSRIs can impact fish feeding behaviors, which can have impacts on ecological fitness. We exposed hybrid striped bass (Morone saxatilis x Morone chrysops) to low, medium, and high concentrations of sertraline (4.5 ± 0.84 μg/L, 35.4 ± 2.18 μg/L, and 96.8 ± 6.4 μg/L) over six days with six additional recovery days. Concentrations were chosen to compare results with a mixture study previously completed in our lab. Every three days we tracked how long each bass took to consume four fathead minnows (Pimephales promelas) and conducted destructive sampling to obtain brain and plasma samples. Brain and plasma samples were analyzed for sertraline levels and we calculated whole brain serotonin levels. During the exposure period, bass showed an increased time to capture prey, but time to capture prey returned to control levels during the six-day recovery period. Sertraline was detected in brain and plasma during the duration of the experiment, though not always in a dose-dependent fashion. While we demonstrated a relationship between time to capture prey and decrease whole brain serotonin levels, the decrease in time to capture prey during the recovery period suggests the serotonin levels in the brain are not solely responsible for the outward behavioral expression observed.

Impact of the antidepressant citalopram on the behaviour of two different life stages of brown trout

BACKGROUND

Over the last two decades, there has been a constant increase in prescription rates of antidepressants. In parallel, neuroactive pharmaceuticals are making their way into aquatic environments at increasing concentrations. Among the antidepressants detected in the environment citalopram, a selective serotonin reuptake inhibitor, is one of the most commonly found. Given citalopram is specifically designed to alter mood and behaviour in humans, there is growing concern it can adversely affect the behaviour on non-target wildlife.

METHODS

In our study, brown trout were exposed to citalopram (nominal concentrations: 1, 10, 100, 1000 µg/L) in two different life stages. Larvae were exposed at 7 and 11 °C from the eyed ova stage until 8 weeks post yolk sac consumption, and juvenile brown trout were exposed for 4 weeks at 7 °C. At both stages we measured mortality, weight, length, tissue citalopram concentration, behaviour during exposure and behaviour in a stressfull environment. For brown trout larvae additionally hatching rate and heart rate, and for juvenile brown trout the tissue cortisol concentration were assessed.

RESULTS

During the exposure, both larvae and juvenile fish exposed to the highest test concentration of citalopram (1 mg/L) had higher swimming activity and spent longer in the upper part of the aquaria compared to control fish, which is an indicator for decreased anxiety. Most probably due to the higher swimming activity during the exposure, the juveniles and larvae exposed to 1 mg/L citalopram showed decreased weight and length. Additionally, in a stressful artificial swimming measurement device, brown trout larvae displayed the anxiolytic effect of the antidepressant by reduced swimming activity during this stress situation, already at concentrations of 100 µg/L citalopram. Chemical analysis of the tissue revealed rising citalopram tissue concentrations with rising exposure concentrations. Tissue concentrations were 10 times higher in juvenile fish compared to brown trout larvae. Fish plasma concentrations were calculated, which exceeded human therapeutic levels for the highest exposure concentration, matching the behavioural results. Developmental parameters like hatching rate and heart rate, as well as mortality and tissue cortisol content were unaffected by the antidepressant. Overall, we could trace the pharmacological mode of action of the antidepressant citalopram in the non-target organism brown trout in two different life stages.

Reduced anxiety is associated with the accumulation of six serotonin reuptake inhibitors in wastewater treatment effluent exposed goldfish Carassius auratus

Pharmaceuticals and personal care products (PPCPs) have been found in wastewater treatment plant (WWTP) effluents and their recipient watersheds. To assess the potential of WWTP effluents to alter fish behaviour, we caged male goldfish (Carassius auratus) for 21-days at three sites along a contamination gradient downstream from a WWTP which discharges into Cootes Paradise Marsh, on the western tip of Lake Ontario. We also included a fourth caging site as an external reference site within Lake Ontario at the Jordan Harbour Conservation Area. We then measured concentrations of PPCPs and monoamine neurotransmitters in caged goldfish plasma, and conducted behavioural assays measuring activity, startle response, and feeding. We detected fifteen different PPCPs in goldfish plasma including six serotonin reuptake inhibitors (amitriptyline, citalopram, fluoxetine/norfluoxetine, sertraline, venlafaxine, and diphenhydramine). Plasma concentrations of serotonin were significantly greater in plasma of fish caged closer to the WWTP effluent outfall site. The fish caged near and downstream of the WWTP effluent were bolder, more exploratory, and more active overall than fish caged at the reference site. Taken together, our results suggest that fish downstream of WWTPs are accumulating PPCPs at levels sufficient to alter neurotransmitter concentrations and to also impair ecologically-relevant behaviours.

An AOP analysis of selective serotonin reuptake inhibitors (SSRIs) for fish

Pharmaceuticals and personal care products (PPCPs) are found in measureable quantities within the aquatic environment. Selective serotonin reuptake inhibitor (SSRI) antidepressants are one class of pharmaceutical compound that has received a lot of attention. Consistent with most PPCPs, the pharmacokinetics and physiological impacts of SSRI treatment have been well-studied in small mammals and humans and this, combined with the evolutionary conservation of the serotonergic system across vertebrates, allows for the read-across of known SSRI effects in mammals to potential SSRI impacts on aquatic organisms. Using an Adverse Outcome Pathway (AOP) framework, this review examines the similarities and differences between the mammalian and teleost fish SSRI target, the serotonin transporter (SERT; SLC6A4), and the downstream impacts of elevated extracellular serotonin (5-HT; 5-hydroxytryptamine), the consequence of SERT inhibition, on organ systems and physiological processes within teleost fish. This review also intends to reveal potentially understudied endpoints for SSRI toxicity based on what is known to be controlled by 5-HT in fish.

Adult vertebrate behavioural aquatic toxicology: Reliability and validity

Current advances in the ability to assay adult aquatic vertebrate behaviour are potentially very useful to aquatic toxicologists wishing to characterise the effects of pollutants on behaviour, cognition or neurodevelopment. This review considers two specific challenges faced by researchers wishing to exploit these technologies: maximising reliability and validity. It will suggest two behavioural procedures, with the potential for automation and high-throughput implementation, which can be used to measure social cohesion and anxiety, two areas of interest in behavioural aquatic toxicology. In addition, the review will make recommendations about how these procedures (and others) could be carried out to maximise reliability and validity.

Selective serotonin reuptake inhibitors and β-blocker transformation products may not pose a significant risk of toxicity to aquatic organisms in wastewater effluent-dominated receiving waters

A probabilistic ecological risk assessment was conducted for the transformation products (TPs) of 3 β-blockers (atenolol, metoprolol, and propranolol) and 5 selective serotonin reuptake inhibitors (SSRIs; citalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline) to assess potential threats to aquatic organisms in effluent-dominated surface waters. To this end, the pharmacokinetic literature, the University of Minnesota's Biocatalysis/Biodegradation Database Pathway Prediction System aerobic microbial degradation software, and photolysis literature pertaining to β-blockers and SSRIs were used to determine their most likely TPs formed via human metabolism, aerobic biodegradation, and photolysis, respectively. Monitoring data from North American and European surface waters receiving human wastewater inputs were the basis of the exposure characterizations of the parent compounds and the TPs, where available. In most cases, where monitoring data for TPs did not exist, we assumed a conservative 1:1 parent-to-TP production ratio (i.e., 100% of parent converted). The US Environmental Protection Agency (USEPA)'s EPISuite and ECOSAR v1.11 software were used to estimate acute and chronic toxicities to aquatic organisms. Hazard quotients, which were calculated using the 95(th) percentile of the exposure distributions, ranged from 10(-11) to 10(-3) (i.e., all significantly less than 1). Based on these results, the TPs of interest would be expected to pose little to no environmental risk in surface waters receiving wastewater inputs. Overall, we recommend developing analytical methods that can isolate and quantify human metabolites and TPs at environmentally relevant concentrations to confirm these predictions. Further, we recommend identifying the major species of TPs from classes of pharmaceuticals that could elicit toxic effects via specific modes of action (e.g., norfluoxetine via the serotonin 5-hydroxytryptamine [5-HT]1A receptors) and conducting aquatic toxicity tests to confirm these findings. To our knowledge, this is the first quantitative probabilistic ecotoxicological assessment of all of the predicted and probable TPs of these pharmaceuticals, and our approach provides a framework for future such studies with other compound classes as data become available.

Reviewing the serotonin reuptake inhibitors (SSRIs) footprint in the aquatic biota: uptake, bioaccumulation and ecotoxicology

Selective serotonin re-uptake inhibitors (SSRIs) antidepressants are amongst the most prescribed pharmaceutical active substances throughout the world. Their presence, already described in different environmental compartments such as wastewaters, surface, ground and drinking waters, and sediments, and their remarkable effects on non-target organisms justify the growing concern about these emerging environmental pollutants. A comprehensive review of the literature data with focus on their footprint in the aquatic biota, namely their uptake, bioaccumulation and both acute and chronic ecotoxicology is presented. Long-term multigenerational exposure studies, at environmental relevant concentrations and in mixtures of related compounds, such as oestrogenic endocrine disruptors, continue to be sparse and are imperative to better know their environmental impact.