ArticlePDF AvailableLiterature Review

The effects of antidepressants appear to be rapid and at environmentally relevant concentrations: Rapid effects of antidepressants

May 2015
Environmental Toxicology and Chemistry 35(4)

DOI:10.1002/etc.3087

License
CC BY 4.0

Authors:

Alex Ford

University of Portsmouth

Peter P. Fong

Gettysburg College

The effects of antidepressants on wildlife are currently raising some concern due to an increased number of publications indicating biological effects at environmentally relevant concentrations (<100ng/L). These results have been met with some scepticism due to the higher concentrations required to detect effects in some species and the perceived slowness to therapeutic effects recorded in humans and other vertebrates. Since their mode of action is thought to be by modulation of the neurotransmitters serotonin, dopamine, and norepinephrine, aquatic invertebrates that possess transporters and receptors sensitive to activation by these pharmaceuticals are potentially affected by them. We highlight studies on the effects of antidepressants, on particularly crustacean and molluscan groups showing they are susceptible to a wide variety of neuroendocrine disruption at environmentally relevant concentrations (pg-ng/L). Interestingly some effects observed in these species can be observed within minutes to hours of exposure. For example, exposure of amphipod crustaceans to several selective serotonin reuptake inhibitors (SSRIs) can invoke changes in swimming behaviour within hours. In molluscs, exposure to SSRIs can induce spawning in male and female mussels and foot detachment in snails within minutes of exposure. In the light of new studies indicating effects on the human brain with just of dose of SSRIs using magnetic resonance imaging (MRI) scans, we discuss possible reasons for the discrepancy in former results in relation to the "read-across" hypothesis, variation in biomarkers used, modes of uptake, phylogenetic distance, and the affinity to different targets and differential sensitivity to receptors. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Content uploaded by Peter P. Fong

Content may be subject to copyright.

AcceptedPreprint

Critical Review

THE EFFECTS OF ANTIDEPRESSANTS APPEAR TO BE RAPID AND AT

ENVIRONMENTALLY RELEVANT CONCENTRATIONS

ALEX T. FORD and PETER P. FONG

Environ Toxicol Chem., Accepted Article • DOI: 10.1002/etc.3087

Accepted Article

"Accepted Articles" are peer-reviewed, accepted manuscripts that have not been edited, formatted, or

in any way altered by the authors since acceptance. They are citable by the Digital Object Identifier

(DOI). After the manuscript is edited and formatted, it will be removed from the “Accepted Articles”

Web site and published as an Early View article. Note that editing may introduce changes to the

manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical

guidelines that apply to the journal pertain. SETAC cannot be held responsible for errors or

consequences arising from the use of information contained in these manuscripts.

AcceptedPreprint

Critical Review Environmental Toxicology and Chemistry

DOI 10.1002/etc.3087

THE EFFECTS OF ANTIDEPRESSANTS APPEAR TO BE RAPID AND AT

ENVIRONMENTALLY RELEVANT CONCENTRATIONS

Running title: Rapid effects of antidepressants

ALEX T. FORD* and PETER P. FONG

 Institute of Marine Sciences, School of Biological Sciences, University of Portsmouth, Ferry Road,

Portsmouth, United Kingdom

Department of Biology, Gettysburg College, 300 N. Washington St., Gettysburg, Pennsylvania, USA

* Address correspondence to alex.ford@port.ac.uk

Submitted 27 February 2015; Returned for Revision 15 April 2015; Accepted 26 May 2015

AcceptedPreprint

Abstract: The effects of antidepressants on wildlife are currently raising some concern due to an

increased number of publications indicating biological effects at environmentally relevant

concentrations (<100ng/L). These results have been met with some scepticism due to the higher

concentrations required to detect effects in some species and the perceived slowness to therapeutic

effects recorded in humans and other vertebrates. Since their mode of action is thought to be by

modulation of the neurotransmitters serotonin, dopamine, and norepinephrine, aquatic invertebrates that

possess transporters and receptors sensitive to activation by these pharmaceuticals are potentially

affected by them. We highlight studies on the effects of antidepressants, on particularly crustacean and

molluscan groups showing they are susceptible to a wide variety of neuroendocrine disruption at

environmentally relevant concentrations (pg-ng/L). Interestingly some effects observed in these species

can be observed within minutes to hours of exposure. For example, exposure of amphipod crustaceans

to several selective serotonin reuptake inhibitors (SSRIs) can invoke changes in swimming behaviour

within hours. In molluscs, exposure to SSRIs can induce spawning in male and female mussels and foot

detachment in snails within minutes of exposure. In the light of new studies indicating effects on the

human brain with just of dose of SSRIs using magnetic resonance imaging (MRI) scans, we discuss

-

variation in biomarkers used, modes of uptake, phylogenetic distance, and the affinity to different

Keywords: SSRIs, pharmaceuticals; pollution; neuroendocrine

AcceptedPreprint

BACKGROUND

A number of recent studies have raised concerns that antidepressants in aquatic ecosystems

maybe an environmental concern [1-6]. Prescriptions of antidepressants have been rapidly increasing in

some countries [7] with studies indicating that antidepressants are taken by 1 in 10 of the population

[8]. These drugs are used to treat a wide range from conditions from depression, anxiety and bipolar

disorders [9]. There are currently a wide range of antidepressants in medical use which include some of

the older prescribed tricyclic compounds (TCAs; e.g. Amitriptyline), the serotonin reuptake inhibitors

(SSRIs; e.g. Fluoxetine), the serotonin and norepinephrine reuptake inhibitors (SNRIs; e.g.

Venlaflaxine) plus serotonin antagonist and reuptake inhibitors (SARIs; e.g. Trazodone).

Concentrations of antidepressants in water bodies vary considerably but have been detected in

freshwater [3, 10-14], groundwater [15] and seawater [16]. In arid and semi-arid parts of the world,

ephemeral streams can be dominated by municipal and/or industrial effluent discharges, particularly in

urbanized watersheds [17]. Therefore some aquatic organisms are likely to be receiving relatively high

and constant exposure to serotonergic and neurologically active drugs. Furthermore, recent studies have

shown the capacity of aquatic organisms to bioaccumulate these compounds [18-21]. Despite the

widespread presence of antidepressants in the aquatic environment, bioactive properties (both

neruological and hormonal), capacity to bioaccumulate in tissues and relatively similar prescription

rates of the concentraceptive pill; it was recently highlighted that the body of research on synthetic

estrogen exposure hugely outweighs the amount currently known for neurological drugs [22].

EFFECTS IN WILDLIFE AT ENVIRONMENTALLY RELEVANT CONCENTRATIONS

The concentrations of antidepressants in the aquatic environment range from the ng to µg/L,

with most studies reporting concentrations sub-100ng/L. The scientific literature has increased in the

number publications highlighting effects of antidepressants observed at very low environmentally

relevant concentrations [6]. These include induction of spawning in bivalves [23,24], altered

cAMP/PKA pathways and serotonin (5-HT) expression in mussels [25]; altered mobility in snails [26],

altered memory, cognitive function and altered ability to camouflage in cuttlefish [27, 28]; induced

AcceptedPreprint

phototaxis and altered activity in amphipods [4, 29-31]; gene expression of putative serotonergic

pathways in amphipods [31]; altered reproduction [21], activity [32] and embryonic/development

endpoints in fish [33]. Therefore one might conclude that the effects of these compounds are diverse

and potentially impact a wide range of invertebrate and vertebrate Phyla.

Fong and Ford [6] recently highlighted that many of these studies report non-monotonic

concentration response curves [6, 31-33]. The low dose effects reported by some studies have been

questioned as to whether they are in fact artefacts, and whether they are repeatable [34]. Several studies

have also been criticised due to limitations in study design including; use of novel biomarkers, large

interspecies variability; nominal concentrations and low numbers of concentrations used [34,35].

Therefore, calls [22] have been made for laboratories to repeat their studies and those of others to

appropriately assess the risk posed by these compounds. Vandenburg et al [36] recently conducted a

large review of cell culture, animal and epidemiology studies and concluded that non-monotonic

responses and low-dose effects are remarkably common in studies of natural hormones and EDCs.

They further went on to suggest that fundamental changes in chemical testing and safety determination

are needed to protect human health. Accepting some of the limitations of recent studies it seems

reasonable to assume that hormetic effects might also be found in serotonergic drugs.

ARE RAPID EFFECTS THAT UNUSUAL?

One of the most intriguing results of some of the reported studies is that effects can sometimes

be observed in very short periods of time [31]. Zebra mussels can be significantly induced to spawn

within minutes of both fluoxetine and fluvoxamine exposure at concentrations as low as 300 and 430

ng/L respectively. For example, Fong [23] found that 70 % of male zebra mussels could be induced to

spawn in one hour or less in 1 nM (430 ng/L) fluvoxamine. Altered oocyte and spermatozoan densities

were observed in zebra mussels exposure to fluoxetine at 20 & 200ng/L following several days

exposure [24]. A number of studies have looked at the effects of fluoxetine on activity measurements in

amphipods, and similarly found effects within very short timeframes [6, 29-31]. For example, within

less than 2 hours of exposure the freshwater amphipod, Gammarus pulex display altered activity

measured following exposure to fluoxetine at low concentrations [29,30]. The experimental protocol

AcceptedPreprint

used a 30-minute acclimation period followed by a 1.5hrs recording using electrical conductance

 the greatest effects on activity were observed

at 10-100ng/L fluoxetine. In another study using the marine/estuarine amphipod Echinogammarus

marinus

fluoxetine exposure with the greatest effects observed at 10-100ng/L [4]. These behavioural effects

were also observed following two and three weeks exposure. The behavioural effects recorded in the

amphipods corresponded to those when exposed to serotonin (5-HT) or infected with serotonin

modulating parasites. Using an alternative method of behavioural analysis, the activity of E. marinus

was recorded using Daniovision (Noldus) with Ethovion XT software (v8.1) following exposure to the

SSRIs sertraline and fluoxetine [31]. Significant effects of the amphipods activity (velocity mm/s) were

recorded after 1 day for fluoxetine and both 1 hour and 1 day for sertraline. Similarly the greatest

effects were observed at 100ng/L with exposed organisms displaying elevated velocities under both

dark and light conditions. Following 8 days exposure there was a significant down regulation of genes



note that neither compounds (fluoxetine or sertraline) elicited effects on velocity after 8 days.

Therefore, albeit with nominal concentrations and the relatively few studies done to date, there is some

repeatability in the low dose effects observed.

Whilst we believe many of the observed effects can be attributed to different modes of action

(MOAs) and not exclusively by via 5-HT re-uptake inhibition, it is important to mention the role of pH

on the toxicokinetics and uptake of antidepressants. A number of recent studies have highlighted the

changes in the pH can strongly influence the ionization of antidepressants resulting in different uptake

rates and consequently toxicity [37-42]. Noteworthy is the increased toxicity observed at higher pH.

Whilst pH of the medium is undoubtedly important since the hydrophobicity of the compound

would affect its ability to cross membranes and enter cells, the route of uptake and the mechanism of

action would determine the target tissues and cell membranes to cross. The route of uptake of

antidepressants in aquatic vertebrates like fishes is likely through the gills or oral cavity. Once in the

blood and if capable, they would cross the blood-brain barrier, enter the brain and exert its action by

AcceptedPreprint

blocking reuptake of 5-HT there. Aquatic anurans on the other hand would be capable gill or of

cutaneous uptake before entering the blood. Brooks [43] reported that using probabilistic hazard

assessment and fish plasma modeling approaches, SSRIs and tricyclic antidepressants are predicted to

result in therapeutic hazard to fish (internal fish plasma level equalling mammalian therapeutic dose)

when exposed to water(inhalational) at or below 1µg/L. However, Brooks [43] also stated due to data

limitations we don't know the internal doses of therapeutic or side effects of drugs in fish or

invertebrates.

By contrast to vertebrates the route of antidepressant uptake in invertebrates is likely to vary

with taxonomic group. In bivalve molluscs, the route of uptake could be direct internalization via the

gills. However since bivalves filter water, the entire mantle cavity containing gonads, foot, digestive

gland, and adductor muscles, as well as gills would be exposed to the water where contact with external

receptors would be possible. Matsutani and Nomura [44] have shown that isolated fragments of scallop

ovaries will release eggs when treated with 5-HT, suggesting that 5-HT receptors are located directly

on the gonad. Isolated mussel siphons and mantle tissues can also be induced to contract and relax with

externally applied 5-HT and these responses can be mimicked by vertebrate 5-HT2 receptor ligands

again suggesting the presence of 5-HT receptors directly on the siphon and mantle [45]. Similar to

bivalves, aquatic snails with gills (prosobranchs) or a modified lung (pulmonates) could take up

antidepressants via these respiratory surfaces, but the foot and all tissues within the mantle cavities are

also available surfaces for uptake.

In crustaceans with a heavy exoskeleton that covers most of their body like crabs, crayfish, and

shrimps, antidepressants could become internalized via the branchial cavity and then enter the

hemocoelomic cavity, but in others that lack gills, antidepressants would have to get across the general

body surface. Once in the hemocoelomic cavity they can become directly in contact with thoracic and

abdominal ganglia of the ventral nerve cord both receptive to and capable of producing 5-HT [46-48].

In planktonic crustaceans with a thin exoskeleton and a large surface area to volume ratio such as

Daphnia, uptake could occur via the feeding current into the filtering chamber, but a major site of

respiratory gas exchange occurs at the inner wall of the carapace [49]. Marine worms can have

AcceptedPreprint

elaborate uptake structures such as parapodia, tentacles, gills, and palps, [50] and uptake could be

through those structures, across the general body surface, or via ingestion.

Recently, Karlsson et al [41] examined the route of uptake of the pharmaceuticals triclosan,

diclofen, and fluoxetine into the aquatic oligochaete, Lumbriculus variegatus. In this worm, the route

of uptake could either be integumental or through the oral cavity, and they cleverly used an oligochaete

that regenerates head and tail segments, thus head removal would inhibit ingestion but not integumental

uptake. They found that that there was no significant difference in uptake of 14C-labelled fluoxetine

between feeding and non-feeding (headless) worms, although they did find that the antibiotic triclosan

was taken up more by feeding worms. Their results indicate that even for an aquatic organism like an

oligochaete, there could be multiple routes of uptake and therefore the effect of pH on speed of an

antidepressant-induced response depends on the target cells and tissues. The behavioral responses that

workers are measuring (e.g. spawning in bivalves, locomotion in snails, phototaxis in amphipods,

learning and cognition in cephalopods, fecundity in Daphnia) would all be affected by the route of

uptake and mode of action.

Thus, how quickly a response to antidepressants occurs is likely to be dependent upon not only

pH, but whether or not the drug binds to external receptors or is somehow internalized first, travels

through blood vessels, makes its way into a coelomic or hemocoelomic cavity, and then binds to

potentially a multitude of molecular targets.

ANTIDEPRESSANTS AND READ-ACROSS HYPOTHESIS

The read-across hypothesis [51] suggests that a drug will have an effect in non-target organisms

only if the molecular targets have been conserved, resulting in a specific pharmacological effects only

if plasma concentrations are similar to human therapeutic concentrations [52]. One of the specific



appear to match the read-across hypothesis for therapeutic dose concentrations for humans [35].

Fluoxetine is generally prescribed over many weeks to allow for brain concentrations to rise enough to

a concentration whereby beneficial results are observed in the patients (usually within one month [35]).

Therefore, it has been highlighted [34] that the antidepressant concentrations in the water of some of

AcceptedPreprint

these studies are unlikely to produce a concentration of fluoxetine in the nerve synapses matching the

therapeutic dose for humans (50-500µg/L plasma concentration). A recent study nicely demonstrated

that fathead minnows only responded in a tank diving test to measure anxiolytic behaviours when

plasma concentrations of fluoxetine were within a similar or higher concentration range to those of

human therapeutic doses [53]. Therefore, the authors concluded that their study represents the first

direct evidence of measured internal dose response effect of a pharmaceutical in fish, thereby validating

the read-across hypothesis for this compound. This was indeed an eloquent study that clearly

demonstrated that the endpoints observed within the fish (fish anxiety tests) matched those close to

human therapeuticplasma concentrations. How surprised might we have been if they were very much

different? Human therapeutic doses, particularly for antidepressants are often derived from

questionnaires given to patients post treatment, which have themselves been subject to criticism [54].

ading across when interpreting the read-across

hypothesis especially when interpreting disparate endpoints. This is especially true when drugs may

have multiple targets; different affinities for targets in different organisms; or similar biological targets

controlling different biological responses [23].

The evolution of the vertebrates represents a minute timeframe in history compared with the

biological divergence of the invertebrates and their targets for 5-HT and serotonin-like drugs. There are

a number of possible targets for antidepressants like fluoxetine in both vertebrates and invertebrates

other than 5-HT reuptake transporters. Ni and Miledi [55] showed that fluoxetine binds to and blocks

5-HT2C receptors in frog (Xenopus) oocytes. They concluded that fluoxetine is a competitive and

reversible receptor antagonist of 5-HT2C receptors. Garcia-Colunga et al. [56] showed that fluoxetine

blocks both muscle and neuronal nicotinic acetylcholine receptors. 

and SSNRIs has been questioned by clinical psychopharmacologists for many years. These drugs show

binding affinity not only to 5-HT2C receptors but to dopamine reuptake transporters, muscarinic

cholinergic receptors, sigma receptors, and to enzymes such as nitric oxide synthase and a variety of

cytochrome P450s [57]. Recently, studies on 5-HT receptors and 5-HT transporters in the nematode

Caenorhabitis elegans has suggested that antidepressants like fluoxetine are not acting as SSRIs.

AcceptedPreprint

Ranganathan et al. [58] found that fluoxetine induces responses in C. elegans that lack a 5-HT

transporter (mod-5). They suggest that fluoxetine could be acting independently of 5-HT and any 5-HT

transporter. This study confirmed the earlier work by Choy and Thomas [59] who found that fluoxetine

induces neuromuscular activity in the anterior region of C. elegans in 5-HT-deficient mutants and

suggests that drugs like fluoxetine have targets other than 5-HT reuptake transporters. Dempsey et al

[60] showed that fluoxetine stimulates egg laying in C. elegans independent of 5-HT and independent

of the 5-HT transporter. Kullyev et al. [61] demonstrated that fluoxetine binds directly to G-protein

coupled 5-HT receptors in C. elegans. It should be noted that 5-HT transporters have been identified in

all major invertebrate phyla [62]. G-protein coupled 5-HT receptors may have evolved over 750

million years ago, whereas mammalian 5-HT receptor subtypes may have differentiated 90 million

years ago [63]. Thus, the number and type of potential targets of these drugs and the cellular responses

to them is likely to be as diverse as the groups of organisms in which they evolved. Therefore we must

be careful when matching endpoints over large phylogenetic distances even when the biological

systems such as the nervous system are relatively conserved; a point made in several studies

[17,34,35,51,52]. This is especially true when some endpoints are unfeasible to read across such

serotonin/dopamine modulated camouflage or photosensitivity. A recent human based study has

highlighted that a biological response to antidepressants (escitalopram) could be detected following a

single dose (20mg) within several hours using Resting-state functional magnetic resonance imaging (rs-

fMRI) [64]. The authors observed the single dose of a serotonin reuptake inhibitor dramatically alters

functional connectivity throughout the whole brain in healthy subjects. Specifically their analysis

suggested a widespread decrease in connectivity in most cortical and subcortical areas of the brain.

Therefore, some effects of antidepressants in humans are detectable quite rapidly following

antidepressants when measuring more sensitive endpoints. In this instance the plasma concentrations of

escitalopram were 25 ± 13 ng/ml which is not uncommon for this particular SSRI but steady state

concentrations are usually observed following 7-10 days and clinical signs of effects following 1-2

weeks [65,66]. Therefore, biological detectable endpoints might be quite different from human

AcceptedPreprint

therapeutic dose concentrations but still have unknown biological disruption which is an important

distinction in environmental protection.

SUMMARY

Antidepressants are ubiquitous in the aquatic environments impacted by sewage effluent. Whilst

the number of studies assessing their potential for environmental impact is increasing, they still remain

few in number to enable us to fully understand the ecological risk posed by these compounds. Those

studies that have been published show quite variable effect concentrations and some have limitations in

their experimental designs. There does however appear to be mounting evidence that very low

concentrations can impact the biological function of multiple aquatic organisms. A number of studies

have recorded the rapid action of antidepressants on some aquatic species, coupled with this, non-

monotonic concentration response curves have been observed which suggests careful consideration

must be made in experimental design and recording. Given that some aquatic organisms are likely to be

exposed either continuously or sporadically throughout their life histories, especially during critical life

stages, it will be important to ascertain the long term impacts of serotonergic drugs on neural

development. Whilst we have provided strong evidence that we must be cautious when applying to

read-across hypothesis to distant invertebrates, evidence from mammalian models does point to the fact

that long-term exposure to antidepressants may cause damage to neural receptors and architecture. The

physiological and behavioural implications of these changes will be a future challenge for

environmental toxicologists.

Acknowledgment—ATF would like to acknowledge the following awarding bodies for supporting this

research: The EU INTERREG programme entitled Peptide Research Network of Excellence (PeReNE)

and the UK Natural Environmental Research Council (NERC; NE/G004587/1). We are very grateful

for the very thoughtful and constructive comments provided by two anonymous reviewers.

Data availability— No Data available, the present study is a review paper.

AcceptedPreprint

REFERENCES

1. Brooks BW, Foran CM, Richards SM, Weston J, Turner PK, Stanley JK, Solomon KR, Slattery

M, La Point TW. 2003. Aquatic ecotoxicology of fluoxetine. Toxicol Let 142:169183.

2. Johnson DJ, Sanderson H, Brain RA, Wilson CJ, Solomon KR. 2007. Toxicity and hazard of

selective serotonin reuptake inhibitor antidepressants fluoxetine, fluvoxamine, and sertraline to

algae. Ecotoxicol Environ Saf 67:128139.

3. 2009. Aquatic ecotoxicity of the

selective serotonin reuptake inhibitor sertraline hydrochloride in a battery of freshwater test

species. Ecotoxicol Environ Saf 72:434440.

4. Guler Y, Ford AF. 2010. Anti-depressants make amphipods see the light. Aquat Toxicol 99:

397404.

5. Styrishave B, Halling-Sorensen B, Ingerslev F. 2011. Environmental risk assessment of three

selective serotonin reuptake inhibitors in the aquatic environment: A case study including a

cocktail scenario. Environ Toxicol Chem 30: 254261.

6. Fong PP, Ford AT. 2014. The biological effects of antidepressants on the molluscs and

crustaceans: A review. Aquat Toxicol. 151: 413

7. National Centre for Health Statistics (US). (2014). Special Feature on Prescription Drugs.

8. United States Department of Health and Human Services (US DHHP) (2012). HealthUnited

States 2011 with special feature on socioeconomic status and healthDHHS Publication No.

2012, 1232 pp.

9. AHFS, 2013. AHFS Di Monographs. Drugs.com http://www.drugs.com/monograph

10. Kolpin DW, Furlong ET, Meyer MT, Thurman EM, Zaugg SD, Barber LB, Buxton HT. 2002.

Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-

2000: A national reconnaissance. Environ Sci Technol 36: 12021211.

AcceptedPreprint

11. Chen M, Ohman K, Metcalfe C, Ikonomou MG, Amatya P, Wilson J. 2006. Pharmaceuticals

and endocrine disruptors in wastewater treatment effluent and in the water supply system of

Calgary, Alberta, Canada. Water Qual Res J Can 41: 351364.

12. Lajeunesse A, Gagnon C, Sauve S. 2008. Determination of basic antidepressants and their N-

desmethyl metabolites in raw sewage and wastewater using solid-phase extraction and liquid

chromatography-tandem mass spectrometry. Analyt Chem 80: 53255333.

13. Schultz MM, Furlong ET. 2008. Trace analysis of antidepressant pharmaceuticals and their

select degradates in aquatic matrixes by LC/ESI/MS/MS. Analyt Chem 80: 17561762.

14. Schultz MM, Furlong ET, Kolpin DW, Werner SL, Schoenfuss HL, Barber LB, Blazer VS,

Norris DO, Vajda AM. 2010. Antidepressant pharmaceuticals in two U.S. effluent- impacted

streams: occurrence and fate in water and sediment, and selective uptake in fish neural tissue.

Environ Sci Technol 44:19181925.

15. Silva LJG, Lino CM, Meisel LM, Pena A. 2012. Selective serotonin re-uptake inhibitors

(SSRIs) in the aquatic environment: an ecopharmacovigilance approach. Sci Tot Environ

437:185195.

16. Pait AS, Warner RA, Hartwell SI, Nelson JO, Pacheco PA, Mason AL. 2006. Human use

pharmaceuticals in the estuarine environment: A Survey of the Chesapeake Bay, Biscayne Bay

and Gulf of the Farallones. NOS NCCOS 7. Silver Spring, MD. NOAA/NOS/NCCOS/Center

for Coastal Monitoring and Assessment. 21pp.

17. Brooks BW, Riley TM, Taylor RD. 2006. Water quality of effluent-dominated ecosystems:

ecotoxicological, hydrological, and management considerations. Hydrobiol 556:365379.

18. Brooks BW, Chambliss CK, Stanley JK, Ramirez A, Banks KE, Johnson RD, Russell JL. 2005.

Determination of select antidepressants in fish froman effluent-dominated stream. Environ Tox

Chem 24:464469.

19. Chu S, Metcalfe CD. 2007. Analysis of paroxetine, fluoxetine and norfluoxetine infish tissues

using pressurized liquid extraction, mixed mode solid phase extrac-tion cleanup and liquid

chromatographytandem mass spectrometry. J Chromatogr A 1163:112118.

AcceptedPreprint

20. Metcalfe CD, Chu S, Judt C, Li H, Oakes KD, Servos MR, Andrews DM. 2010.

Antidepressants and their metabolites in municipal wastewater, and downstream exposure in an

urban watershed. Environ Toxicol Chem 29: 7989.

21. Schultz MM, Painter MM, Bartell SE, Logue A, Furlong ET, Werner SL, Schoenfuss, HL.

2011. Selective uptake and biological consequences of environmentally relevant antidepressant

pharmaceutical exposures on male fathead minnows. Aquat Toxicol 104:3847.

22. Ford AT. (2014). From gender benders to brain benders (and beyond!). Aquat Toxicol 151:1-3

23. Fong PP. 1998. Zebra mussel spawning is induced in low concentrations of putative serotonin

reuptake inhibitors. Biol Bull 194:143149.

24. Lazzara R, Blazquez M, Porte C, Barata C. 2012. Low environmental levels of fluoxetine

induce spawning and changes in endogenous estradiol levels in the zebra mussel Dreissena

polymorpha. Aquat Toxicol 106-107:123-130.

25. Franzellitti S, Buratti S, Valbonesi P, Fabbri E. 2013. The mode of action (MOA) approach

reveals interactive effects of environmental pharmaceuticals on Mytilis galloprovincialis. Aquat

Toxicol 140141: 249256.

26. Fong PP, Hoy CM, 2012. Antidepressants (venlafaxine and citalopram) cause foot detachment

from the substrate in freshwater snails at environmentally relevant concentrations. Mar Fresh

Behav Phys 45:145153

27. Di Poi C, Darmaillacq A-S, Dickel L, Boulouard M, Bellanger C. 2013. Effects of perinatal

exposure to waterborne fluoxetine on memory processing in the cuttlefish Sepia officinalis.

Aquat Toxicol 132-133: 8491.

28. Di Poi C, Bidel F, Dickel L, Bellanger C. 2014. Cryptic and biochemical responses of young

cuttlefish Sepia officinalis exposed to environmentally relevant concentrations of fluoxetine.

Aquatic Toxicology. 151: 3645.

29. De Lange HJ, Noordoven W, Murk AJ, Lürling MFLLW, Peeters ETHM. 2006. Behavioural

responses of Gammaruspulex(Crustacea, Amphipoda) to low concentrations of

pharmaceuticals. Aquat Toxicol 78: 209216.

AcceptedPreprint

30. De Lange HJ, Peeters ET, Lürling MFLLW. 2009. Changes in ventilation and locomotion of

Gammarus pulex (Crustacea, Amphipoda) in response to low concentrations of

pharmaceuticals. Hum Ecol Risk Assess 15:111120.

31. Bossus MC, Guler YZ, Short SJ, Morrison ER, Ford AT. 2014. Behavioural and transcriptional

changes in the amphipod Echinogammarus marinus exposed to two antidepressants, fluoxetine

and sertraline. Aquat Toxicol 151:4656

32. Barry MJ. 2013. Effects of fluoxetine on swimming and behavioural responses ofthe Arabian

killifish. Ecotoxicol 22:425432.

33. Yang M, Qiu W, Chen J, Zhan J, Pan C, Lei X, Wu M. 2014. Growth inhibition and

coordinated physiological regulation of zebrafish (Danio rerio) embryos upon sublethal

exposure to antidepressant amitriptyline. Aquat Toxicol 151:6876

34. Sumpter JP, Donnachie RL, Johnson AC. 2013. The apparently very variable potency of the

anti-depressant fluoxetine. Aquat Toxicol 151:5760

35. Sumpter JP, Margiotta-Casaluci L. 2013. Are some invertebrates exquisitely sensitive to the

human pharmaceutical fluoxetine? Aquat Toxicol 146:259260

36. Vandenberg LN, Colborn T, Hayes TB, Heindel JJ, Jacobs Jr DR, Lee DH, Shioda T, Soto AM,

vom Saal FS, Welshons WV, Zoeller RT, Myers, J. P. (2012). Hormones and endocrine-

disrupting chemicals: low-dose effects and nonmonotonic dose responses. Endocrine reviews,

33: 378455.

37. Nakamura, Y., Yamamoto, H., Sekizawa, J., Kondo, T., Hirai, N., & Tatarazako, N. 2008. The

effects of pH on fluoxetine in Japanese medaka (Oryzias latipes): Acute toxicity in fish larvae

and bioaccumulation in juvenile fish. Chemosphere 70:865873.

38. Valenti, T. W., Perez‐Hurtado, P., Chambliss, C. K., & Brooks, B. W 2009. Aquatic toxicity of

sertraline to Pimephales promelas at environmentally relevant surface water pH. Environmental

Toxicology and Chemistry 28: 2685-2694.

AcceptedPreprint

39. Carter, L. J., Garman, C. D., Ryan, J., Dowle, A., Bergstr, E., Thomas-Oates, J., & Boxall,

A. B. 2014. Fate and Uptake of Pharmaceuticals in Soil-Earthworm Systems. Environmental

Science & Technology 48: 5955-5963.

40. Karlsson, M.V., Marshall, S., Gouin, T. and A.B.A. Boxall. 2015. Routes of uptake of diclofen,

fluoxetine, and triclosan into sediment-dwelling worms. Environmental Toxicology and

Chemistry, in press. DOI 10.1002/etc.3020

41. Sundaram, R., Smith, B., & Clark, T. (in press). pH dependent toxicity of serotonin-selective

reuptake inhibitors in taxonomically diverse freshwater invertebrate species. Marine and

Freshwater Research. http://dx.doi.org/10.1071/MF14015

42. Bostrom, M.L. and O. Berglund, 2015. Influence of pH-dependent aquatic toxicity of ionisable

pharmaceuticals on risk assessments over environmental pH ranges. Water Research 72: 154-

161.

43. Brooks BW. 2014. Fish on Prozac (and Zoloft): Ten years later. Aquatic Toxicology 151: 61-

67.

44. Matsutani, T. and T. Nomura. 1987. In vitro effects of serotonin and prostaglandins on release

of eggs from the ovary of the scallop, Patinopecten yessoensis. General and Comparative

Endocrinology 67(1): 111-118.

45. Ram, J.L., D. Moore, S. Putchakayala, A.A. Paredes, D. Ma, and R.P. Croll. 1999. Sertonergic

responses of the siphons and adjacent mantle tissue of the zebra mussel, Dreissena polymorpha.

Comparative Biochemistry and Physiology C 124(2): 211-220.

46. Beltz, B. S., & Kravitz, E. A. (1983). Mapping of serotonin-like immunoreactivity in the lobster

nervous system. The Journal of Neuroscience, 3(3), 585-602.

47. Harzsch, S., & Waloszek, D. (2000). Serotonin-immunoreactive neurons in the ventral nerve

cord of Crustacea: a character to study aspects of arthropod phylogeny. Arthropod structure &

development, 29(4), 307-322.

AcceptedPreprint

48. Sosa, M. A., Spitzer, N., Edwards, D. H., & Baro, D. J. (2004). A crustacean serotonin receptor:

cloning and distribution in the thoracic ganglia of crayfish and freshwater prawn. Journal of

Comparative Neurology, 473(4), 526-537.

49. Pirow, R., F. Wollinger and R.J. Paul. 1999. The sites of respiratory gas exchange in the

planktonic crustacean Daphnia magna: an in vivo study employing blood haemoglobin as an

internal oxygen probe. J. Experimental Biology 202(22): 3089-3099.

50. Ruppert, E.E., R.S. Fox, and R.D. Barnes. 2004. Invertebrate Zoology: A functional

evolutionary approach. 7th edition, Brooks Cole Thomson, Publishers, Belmont, California,

USA. 963 pp.

51. Huggett DB, Cook JC, Ericson JF, Williams RT. 2003. A theoretical model for utilizing

mammalian pharmacologyand safety data to prioritized potential impacts ofhuman

pharmaceuticals to fish. Hum Ecol RiskAssess 9:17891800

52. Rand-Weaver M, Margiotta-Casaluci L, Patel A, Panter GH, Owen SF, Sumpter JP. 2013. The

read-across hypothesis and environmental risk assessment of pharmaceuticals. Environ Sci

Technol 47:1229712304.

53. Margiotta-Casaluci L, Owen SF, Cumming RI, de Polo A, Winter MJ, Panter GH, Rand-

Weaver, M, Sumpter JP. 2014. Quantitative Cross-Species Extrapolation between Humans and

Fish: The Case of the Anti-Depressant Fluoxetine. PLoS ONE 9(10): e110467.

54. Bagby RM, Ryder AG, Schuller DR, Marshall MB. 2004. The Hamilton Depression Rating

Scale: has the gold standard become a lead weight? Am J Pschariety. 161:21632177

55. Ni YG, Miledi R. 1997. Blockage of 5-HT2C receptors by fluoxetine (Prozac). Proc. Nat. Acad.

Sci. USA 94: 20362040.

56. Garcia-Colunga J, Awad JN, Miledi R. 1997. Blockage of muscle and neuronal nicotinic

acetylcholine receptors by fluoxetine (Prozac). Proc. Nat. Acad. Sci. USA 94:20412044.

57. Stahl SM. 1998. Not so selective serotonin reuptake inhibitors. J. Clinical Psychiatry 59:343

344.

AcceptedPreprint

58. Ranganathan R, Sawin ER, Trent C, Horvitz HR. 2001. Mutations in the Caenorhabditis elegans

serotonin reuptake transporter MOD-5 reveal serotonin-dependent and-independent activities of

fluoxetine. J Neurosci 21: 58715884.

59. Choy RKM, Thomas JH. 1999. Fluoxetine-resistant mutants in C. elegans define a novel family

of transmembrane proteins. Mol Cell 4: 143152

60. Dempsey CM. 2005. Serotonin (5HT), fluoxetine, imipramine and dopamine target distinct

5HT receptor signaling to modulate Caenorhabditis elegans egg-laying behavior. Genetics

169:14251436.

61. Kullyev ACM. Dempsey S, Miller C-JK, Hapiak VM, Komuniecki RW, Griffin CT Sze JY.

2010. A Genetic survey of fluoxetine action on synaptic transmission in Caenorhabditiselegans.

Genetics 186: 929941.

62. Caveney S, Cladman W, Verellen L, DonlyC. 2006. Ancestry of neuronal monoamine

transporters in the Metazoa. J. Exp. Biol. 209: 48584868.

63. Peroutka SJ, Howell TA. 1994. The molecular evolution of G protein-coupled receptors: Focus

on 5-hydroxytryptamine receptors. Neuropharmacology 33: 319-324.

64. Schaefer A, Burmann I, Regenthal R, Arélin K, Barth C, Pampel A, Villringer A, Margulies

DS, Sacher J, 2014. Serotonergic Modulation of Intrinsic Functional Connectivity. Current

Biology, 24:23142318

65. Rao N. 2007. The clinical pharmacokinetics of escitalopram. Clin pharmacokin 46: 281290.

66. Sanchez C, Reines EH, Montgomery SA. 2014. A comparative review of escitalopram,

paroxetine, and sertraline: are they all alike? Int clin psychopharm 29: 185196.

Effect of an antidepressant on aquatic ecosystems in the presence of microplastics: A mesocosm study

Article

Jun 2024

Emerging pollutants, such as pharmaceuticals and microplastics have become a pressing concern due to their widespread presence and potential impacts on ecological systems. To assess the ecosystem-level effects of these pollutants within a multi-stressor context, we simulated real-world conditions by exposing a near-natural multi-trophic aquatic food web to a gradient of environmentally relevant concentrations of fluoxetine and microplastics in large mesocosms over a period of more than three months. We measured the biomass and abundance of different trophic groups, as well as ecological functions such as nutrient availability and decomposition rate. To explore the mechanisms underlying potential community and ecosystem-level effects, we also performed behavioral assays focusing on locomotion parameters as a response variable in three species: Daphnia magna (zooplankton prey), Chaoborus flavicans larvae (invertebrate pelagic predator of zooplankton) and Asellus aquaticus (benthic macroinvertebrate), using water from the mesocosms. Our mesocosm results demonstrate that presence of microplastics governs the response in phytoplankton biomass, with a weak non-monotonic dose-response relationship due to the interaction between microplastics and fluoxetine. However, exposure to fluoxetine evoked a strong non-monotonic dose-response in zooplankton abundance and microbial decomposition rate of plant material. In the behavioral assays, the locomotion of zooplankton prey D. magna showed a similar non-monotonic response primarily induced by fluoxetine. Its predator C. flavicans, however, showed a significant non-monotonic response governed by both microplastics and fluoxetine. The behavior of the decomposer A. aquaticus significantly decreased at higher fluoxetine concentrations, potentially leading to reduced decomposition rates near the sediment. Our study demonstrates that effects observed upon short-term exposure result in more pronounced ecosystem-level effects following chronic exposure.

Pharmaceutical Residues in Edible Oysters along the Coasts of the East and South China Seas and Associated Health Risks to Humans and Wildlife

Article

Mar 2024
ENVIRON SCI TECHNOL

The investigation of pharmaceuticals as emerging contaminants in marine biota has been insufficient. In this study, we examined the presence of 51 pharmaceuticals in edible oysters along the coasts of the East and South China Seas. Only nine pharmaceuticals were detected. The mean concentrations of all measured pharmaceuticals in oysters per site ranged from 0.804 to 15.1 ng g–1 of dry weight, with antihistamines being the most common. Brompheniramine and promethazine were identified in biota samples for the first time. Although no significant health risks to humans were identified through consumption of oysters, 100–1000 times higher health risks were observed for wildlife like water birds, seasnails, and starfishes. Specifically, sea snails that primarily feed on oysters were found to be at risk of exposure to ciprofloxacin, brompheniramine, and promethazine. These high risks could be attributed to the monotonous diet habits and relatively limited food sources of these organisms. Furthermore, taking chirality into consideration, chlorpheniramine in the oysters was enriched by the S-enantiomer, with a relative potency 1.1–1.3 times higher when chlorpheniramine was considered as a racemate. Overall, this study highlights the prevalence of antihistamines in seafood and underscores the importance of studying enantioselectivities of pharmaceuticals in health risk assessments.

Parental exposure to antidepressants has lasting effects on offspring? A case study with zebrafish

Article

Full-text available

Apr 2024
CHEMOSPHERE

Fish have common neurotransmitter pathways with humans, exhibiting a significant degree of conservation and homology. Thus, exposure to fluoxetine makes fish potentially susceptible to biochemical and physiological changes, similarly to what is observed in humans. Over the years, several studies demonstrated the potential effects of fluoxetine on different fish species and at different levels of biological organization. However, the effects of parental exposure to unexposed offspring remain largely unknown. The consequences of 15-day parental exposure to relevant concentrations of fluoxetine (100 and 1000 ng/L) were assessed on offspring using zebrafish as a model organism. Parental exposure resulted in offspring early hatching, non-inflation of the swimming bladder, increased malformation frequency, decreased heart rate and blood flow, and reduced growth. Additionally, a significant behavioral impairment was also found (reduced startle response, basal locomotor activity, and altered non-associative learning during early stages and a negative geotaxis and scototaxis, reduced thigmotaxis, and anti-social behavior at later life stages). These behavior alterations are consistent with decreased anxiety, a significant increase in the expression of the monoaminergic genes slc6a4a (sert), slc6a3 (dat), slc18a2 (vmat2), mao, tph1a, and th2, and altered levels of monoaminergic neurotransmitters. Alterations in behavior, expression of monoaminergic genes, and neurotransmitter levels persisted until offspring adulthood. Given the high conservation of neuronal pathways between fish and humans, data show the possibility of potential transgenerational and multigenerational effects of pharmaceuticals’ exposure. These results reinforce the need for transgenerational and multigenerational studies in fish, under realistic scenarios, to provide realistic insights into the impact of these pharmaceuticals.

Effects of a common antidepressant on behavior and dispersal in the globally invasive freshwater eastern mosquitofish (Gambusia holbrooki)

Article

Full-text available

Jan 2024
ENVIRON BIOL FISH

Anthropogenic pollutants are an ongoing problem in aquatic environments. One such pollutant is fluoxetine, a selective serotonin reuptake inhibitor commonly known by the brand name Prozac. We still do not fully understand how such medical wastes affect aquatic organisms, specifically, how they affect traits that are important to the ecology and evolution of populations and species. We examined how chronic exposure to a field-relevant concentration of fluoxetine (440 ng/L) affects different behaviors in wild-caught Gambusia holbrooki. We tested fish social behavior, cognitive flexibility, and tendency to disperse in an artificial stream. We found that exposure to fluoxetine did not affect performance in any of the aforementioned behavioral assays. Furthermore, neither sociability nor cognitive flexibility predicted movement in the dispersal assay. At least for G. holbrooki, it appears that fluoxetine may not have large effects on the tested predictive behaviors or dispersal itself. While these results suggest that fluoxetine exposure may have limited effects on a key trait important in ecology and evolution—namely dispersal—it may still affect other traits not tested in this study.

Differences in the response of Chlorella pyrenoidosa to three antidepressants and their mixtures in different light–dark start cycles

Article

Full-text available

Jan 2024
ENVIRON SCI POLLUT R

The use of antidepressants is increasing along with the continuing spike in the prevalence of depression worldwide. As a result, more and more antidepressants are entering the water and probably does harm to the aquatic organisms and even human health. Therefore, three antidepressants, including fluoxetine (FLU), citalopram (CIT), and aspirin (APC), were selected to investigate the toxic risks of antidepressants and their mixtures to a freshwater green alga Chlorella pyrenoidosa (C. pyrenoidosa). Due light is critical for the growth of green algae, six different light–dark cycle experiments were constructed to investigate the differences in toxicity and interaction responses of C. pyrenoidosa to antidepressants and their ternary mixture designed by the uniform design ray method. The toxic effects of individual antidepressants and their mixtures on C. pyrenoidosa were systematically investigated by the time-dependent microplate toxicity analysis (t-MTA) method. Toxicity interactions (synergism or antagonism) within mixtures were analyzed by the concentration addition (CA) and the deviation from the CA model (dCA) models. The results showed that the toxicities of the three antidepressants were different, and the order was FLU > APC > CIT. Light–dark cycles obviously affect the toxicity of three antidepressants and their combined toxicity interaction. Toxicity of the three antidepressants increases with the duration of light but decreases with the duration of darkness. The ternary antidepressant mixture exhibits antagonism, and the longer the initial lighting is, the stronger the antagonism. The antagonism of the ternary mixture is also affected by exposure time and mixture components’ pi as well as exposure concentration.

Understanding the differential impacts of two antidepressants on locomotion of freshwater snails (Lymnaea stagnalis)

Article

Full-text available

Jan 2024
ENVIRON SCI POLLUT R

There is growing evidence of negative impacts of antidepressants on behavior of aquatic non-target organisms. Accurate environmental risk assessment requires an understanding of whether antidepressants with similar modes of action have consistent negative impacts. Here, we tested the effect of acute exposure to two antidepressants, fluoxetine and venlafaxine (0–50 µg/L), on the behavior of non-target organism, i.e., freshwater pond snail, Lymnaea stagnalis . As compounds interact with chemical cues in the aquatic ecosystems, we also tested whether the effects altered in the presence of bile extract containing 5α-cyprinol sulfate (5α-CPS), a characterized kairomone of a natural predator, common carp ( Cyprinus carpio ). Behavior was studied using automated tracking and analysis of various locomotion parameters of L. stagnalis. Our results suggest that there are differences in the effects on locomotion upon exposure to venlafaxine and fluoxetine. We found strong evidence for a non-monotonic dose response on venlafaxine exposure, whereas fluoxetine only showed weak evidence of altered locomotion for a specific concentration. Combined exposure to compounds and 5α-CPS reduced the intensity of effects observed in the absence of 5α-CPS, possibly due to reduced bioavailability of the compounds. The results highlight the need for acknowledging different mechanisms of action among antidepressants while investigating their environmental risks. In addition, our results underline the importance of reporting non-significant effects and acknowledging individual variation in behavior for environmental risk assessment. Graphical Abstract

Differential bioconcentration and sensitivity of Dreissena polymorpha and Dreissena rostriformis bugensis to the antidepressant sertraline

Article

Nov 2024
J HAZARD MATER

Environmental fluoxetine promotes skin cell proliferation and wound healing

Article

Sep 2024

Evaluating non-monotonic dose-response relationships in ecotoxicological risk assessment: A case study based on a systematic review of data on fluoxetine

Article

Jul 2024
CHEMOSPHERE

Footprint of green synthesizing ingredients on the environment and pharmaceuticals

Article

Mar 2024

Environmental pollution caused by toxic pharmaceutical ingredients and other human hazards is a sign of danger for the biological life on earth. Considering the importance of green revolution including the green pharmaceutical industries, the scientists and environmental protection agencies recently highlighted green chemical ingredients and biodegradable products as extreme protection line for our environment. An electronic search was conducted utilizing Science Finder, Medline, Scopus, and Google Scholar to gather English-language articles pertaining to chemical environmental hazards and green foot printing. Our study explored that environmental risks are majorly caused by emitted chemical pharma ingredients and non-biodegradable products such as antibiotics, analgesics, antidepressants, antihypertensive, contraceptives, steroids, hormones, and polychlorinated dioxins. Although the detected amounts of these ingredients are very small, however, such minute quantities are enough to be considered toxic for human, animal, and aquatic lives. Moreover, a significant number of drugs undergo incomplete metabolism in both humans and animals, contributing to environmental hazards alongside the substantial volume of non-biodegradable industrial waste. The current review highlights the impact of pharmaceutical waste on environmental safety, health of living world, and the recent achievements in adopting green pharma as an alternative strategy. Additionally, keeping in view the potential risk of production of toxic ingredients and emission by conventional chemical methods, this review further focuses on the footprint of green (plant source) synthesized ingredients for utilization in various pharma sectors and their possible implication in environmental protection.

Quantitative Cross-Species Extrapolation between Humans and Fish: The Case of the Anti-Depressant Fluoxetine

Article

Full-text available

Oct 2014
PLOS ONE

Fish are an important model for the pharmacological and toxicological characterization of human pharmaceuticals in drug discovery, drug safety assessment and environmental toxicology. However, do fish respond to pharmaceuticals as humans do? To address this question, we provide a novel quantitative cross-species extrapolation approach (qCSE) based on the hypothesis that similar plasma concentrations of pharmaceuticals cause comparable target-mediated effects in both humans and fish at similar level of biological organization (Read-Across Hypothesis). To validate this hypothesis, the behavioural effects of the anti-depressant drug fluoxetine on the fish model fathead minnow (Pimephales promelas) were used as test case. Fish were exposed for 28 days to a range of measured water concentrations of fluoxetine (0.1, 1.0, 8.0, 16, 32, 64 mg/L) to produce plasma concentrations below, equal and above the range of Human Therapeutic Plasma Concentrations (H T PCs). Fluoxetine and its metabolite, norfluoxetine, were quantified in the plasma of individual fish and linked to behavioural anxiety-related endpoints. The minimum drug plasma concentrations that elicited anxiolytic responses in fish were above the upper value of the H T PC range, whereas no effects were observed at plasma concentrations below the H T PCs. In vivo metabolism of fluoxetine in humans and fish was similar, and displayed bi-phasic concentration-dependent kinetics driven by the auto-inhibitory dynamics and saturation of the enzymes that convert fluoxetine into norfluoxetine. The sensitivity of fish to fluoxetine was not so dissimilar from that of patients affected by general anxiety disorders. These results represent the first direct evidence of measured internal dose response effect of a pharmaceutical in fish, hence validating the Read-Across hypothesis applied to fluoxetine. Overall, this study demonstrates that the qCSE approach, anchored to internal drug concentrations, is a powerful tool to guide the assessment of the sensitivity of fish to pharmaceuticals, and strengthens the translational power of the cross-species extrapolation. Citation: Margiotta-Casaluci L, Owen SF, Cumming RI, de Polo A, Winter MJ, et al. (2014) Quantitative Cross-Species Extrapolation between Humans and Fish: The Case of the Anti-Depressant Fluoxetine. PLoS ONE 9(10): e110467. doi:10.1371/journal.pone.0110467 Copyright: ß 2014 Margiotta-Casaluci et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. The authors confirm that all the data underlying the findings are fully available from the Dryad database. DOI:10.5061/dryad.b1772. Funding: This work was funded by a Biotechnology and Biological Sciences Research Council (BBSRC) Research Grant (BB/100646X/1), co-funded by the AstraZeneca Global Environment research programme, to JPS and MR-W supporting LM-C. AdP was supported by the Isambard Scholarship awarded by Brunel University. BBSRC had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. SFO is an employee of AstraZeneca; RIC, MJW and GHP were also AstraZeneca employees. AstraZeneca provided support in the form of salaries for authors SFO, RIC, MJW and GHP and grant to JPS and MR-W supporting LM-C, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the 'author contributions' section. Competing Interests: This work was co-funded by the AstraZeneca Global Environment research programme. SFO is an employee of AstraZeneca; RIC, MJW and GHP were also AstraZeneca employees. AstraZeneca is a biopharmaceutical company specialized in the discovery, development, manufacturing and marketing of prescription medicines, including some anxiolytic products. This does not alter our adherence to all the PLoS ONE policies on sharing data and materials.

Changes in Ventilation and Locomotion of Gammarus pulex (Crustacea, Amphipoda) in Response to Low Concentrations of Pharmaceuticals

Article

Full-text available

Feb 2009

Exposure to contaminants below lethal concentrations may affect the performance of organisms, resulting in measurable differences in behavior. We measured the response of the benthic invertebrate Gammarus pulex (Crustacea, Amphipoda) to sublethal concentrations of three pharmaceuticals, fluoxetine, ibuprofen and carbamazepine, and the cationic surfactant cetyltrimethylammonium bromide (CTAB). Responses in behavior during exposure were analyzed using the multivariate method of Principal Response Curves (PRC). The PRC results show that exposure to low pharmaceutical concentrations (range 1-100 ng/l) resulted in increased ventilation, whereas exposure to control or to high concentrations (1  g/l-1 mg/L) resulted in increased locomotion. Exposure to CTAB resulted in decreased locomotion and increased ventilation at increasing concentrations. The results of our experiments indicate that increased ventilation can be used as a general sign of stress, but not necessarily an early warning signal for mortality.

Growth inhibition and coordinated physiological regulation of zebrafish (Danio rerio) embryos upon sublethal exposure to antidepressant amitriptyline

Article

Full-text available

Jan 2014

Amitriptyline is a tricyclic antidepressant used for decades. It is present at low detectable concentrations in the aquatic environment, but relative few studies have focused on its ecotoxicological effects on non-target aquatic animals. The present study conducted an acute toxicity test of waterborne amitriptyline exposure using zebrafish (Danio rerio) embryos 4 to 124h-post-fertilization. Time-dependent lethal concentrations were firstly determined and at mg/L levels. Effects of amitriptyline on zebrafish embryos were then evaluated under amitriptyline exposure at sublethal concentrations of 1, 10, 100ng/L, 1, 10, 100μg/L and 1mg/L. Our results showed that amitriptyline significantly reduced the hatching time and body length of embryos after exposure in a concentration-dependent manner. Our study also revealed that the exposure evoked a coordinated modulation of physiological and biochemical parameters in exposed zebrafish embryos, including alterations of adrenocorticotropic hormone (ACTH) level, oxidative stress and antioxidant parameters, as well as nitric oxide (NO) production and total nitric oxide synthase (TNOS) activity. A U-shaped concentration-dependent response curve was observed in ACTH level in response to amitriptyline exposure. However, both U-shaped and inversed U-shaped curves were indicated in the responses of antioxidant parameters, including total antioxidant capacity, antioxidant enzyme activities (catalase, superoxide dismutase and peroxidase), glutathione content and glutathione reductase activity. Correspondingly, hydroxyl radical formation and lipid peroxidation indices changed in similar U-shaped concentration-dependent patterns, which together the results of antioxidant parameters suggested induction of oxidative stress in embryos exposed to amitriptyline at high concentrations. Moreover, NO production and TNOS activity were both significantly affected by amitriptyline exposure. Notably, significant correlations between these measured parameters were revealed, which suggested a dynamic adaptation process and coordinated regulation of multiple physiological systems in fish embryos to amitriptyline treatment. Furthermore, our study demonstrated that the effective concentrations of amitriptyline for measured parameters in zebrafish embryos were as low as 10ng/L, and thus revealed the potential risk of amitriptyline and other antidepressants to aquatic life.

PH-dependent toxicity of serotonin selective reuptake inhibitors in taxonomically diverse freshwater invertebrate species

Article

Jan 2015

Serotonin selective reuptake inhibitors (SSRIs) are pollutants that influence behaviour, physiology and survival of freshwater animals. Factors influencing the sensitivity of freshwater invertebrates to these drugs must be understood in order to predict their effects on freshwater ecosystems. The toxicities of fluoxetine (Prozac), paroxetine (Paxil) and citalopram (Celexa), were tested in larval Aedes aegypti (Insecta, Diptera), Cypridopsis vidua (Crustacea, Ostracoda) and Hydra vulgaris (Cnidaria, Hydrozoa) across a broad range of ambient pH values. H. vulgaris were most sensitive, with minimal survival in the presence of drugs (1×10-5 molL-1) in all but acidic media, whereas A. aegypti larvae were least sensitive. In all species tested the drugs were toxic in neutral and alkaline media but showed minimal or no toxicity in acidic media, whereas citalopram and fluoxetine enhanced survival of C. vidua in pH 4 media. Increased toxicity in alkaline media supports the hypothesis that the ionisation states of the drugs influences their toxicity by effects on membrane permeability, whereas enhanced survival of C. vidua in acidic media in the presence of SSRIs suggests that serotonergic pathways may be involved in regulation of acid-base balance in this species.

Routes of uptake of diclofenac, fluoxetine, and triclosan into sediment-dwelling worms: Uptake of Pharmaceuticals and Personal Care Products

Article

Apr 2015
ENVIRON TOXICOL CHEM

This study investigated the route and degree of uptake of two ionisable pharmaceuticals (diclofenac and fluoxetine) and one ionisable compound used in personal care products (triclosan) into the sediment dwelling worm, Lumbriculus variegatus. Studies were done on complete worms ('feeding') and worms where the head was absent ('non-feeding') using (14) C labelled ingredients. Biota sediment accumulation factors, based on uptake of (14) C, for 'feeding' worms increased in the order fluoxetine (BSAF = 0.3) < diclofenac (BSAF = 0.5) < triclosan (BSAF = 9), which is correlated with a corresponding increase in log KOW . BSAF estimates are representative of maximum values since the degree of biotransformation in the worms was not quantified. While, no significant differences were seen between the uptake of diclofenac and fluoxetine in feeding and non-feeding worms, the uptake of the more hydrophobic anti-microbial, triclosan, into the 'feeding' worms was significantly greater than the 'non-feeding' worms with the 48h BSAF for feeding worms being 36% higher than for the non-feeding worms. Our results imply that dietary uptake contributes to the uptake of triclosan which may be a result of the high hydrophobicity of the compound. Models that estimate exposure of ionisable substances may need to consider uptake from both the water column and via food, particularly when assessing risks from dynamic exposures to organic contaminants. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Influence of pH-dependent aquatic toxicity of ionizable pharmaceuticals on risk assessments over environmental pH ranges

Article

Apr 2015
WATER RES

Due to variation in pH, ionizable pharmaceuticals entering aquatic environments experience different degrees of ionization, which may affect toxicity. Using data from toxicity testing at only neutral pH may potentially under- or overestimate actual toxicity at pH ranges found in natural aquatic environments. Here we show relative pH-dependent acute toxicity to Daphnia magna for the pharmaceutical weak bases fluoxetine and sertraline, as well as the weak acids naproxen, diclofenac, ibuprofen and ketoprofen. A probabilistic modelling approach using the pH-dependent toxicity data for D. magna and an environmental pH distribution based on over 4000 European running waters from 21 countries predicted that environmental toxicity for the weak bases may be underestimated if pH 7 was assumed. The model predicted median underestimation by a factor of 3, with 90% of the model results ranging from 1 to 6. Consequently, due to the slightly basic nature of the European running waters, weak acid toxicity may be overestimated by a factor of 2. Predicted median toxicity was 0.5 of that assuming pH 7 with 90% of the results ranging from 0.03 to 5. Because aquatic pH exhibits large variation both within and between countries, we advise the use of site-specific risk assessments for ionizable pharmaceuticals in making informed water management decisions.

Serotonergic Modulation of Intrinsic Functional Connectivity

Article

Sep 2014
CURR BIOL

Serotonin functions as an essential neuromodulator that serves a multitude of roles, most prominently balancing mood [1]. Serotonergic challenge has been observed to reduce intrinsic functional connectivity in brain regions implicated in mood regulation [2-4]. However, the full scope of serotonergic action on functional connectivity in the human brain has not been explored. Here, we show evidence that a single dose of a serotonin reuptake inhibitor dramatically alters functional connectivity throughout the whole brain in healthy subjects (n = 22). Our network-centrality analysis reveals a widespread decrease in connectivity in most cortical and subcortical areas. In the cerebellum and thalamus, however, we find localized increases. These rapid and brain-encompassing connectivity changes linked to acute serotonin transporter blockade suggest a key role for the serotonin transporter in the modulation of the functional macroscale connectome.

Fate and Uptake of Pharmaceuticals in Soil-Earthworm Systems

Article

Apr 2014
ENVIRON SCI TECHNOL

Pharmaceuticals present a potential threat to soil organisms, yet our understanding of their fate and uptake in soil systems is limited. This study therefore investigated fate and uptake of 14C labelled carbamazepine, diclofenac, fluoxetine and orlistat in soil-earthworm systems. Sorption coefficients increased in the order of carbamazepine < diclofenac < fluoxetine < orlistat. Dissipation of 14C varied by compound and, for orlistat, there was evidence of formation of non-extractable residues. Uptake of 14C was seen for all compounds. Depuration studies showed complete elimination of 14C for carbamazepine and fluoxetine treatments and partial elimination for orlistat and diclofenac, with >30% of the 14C remaining in the tissue at the end experiment. Pore-water based bioconcentration factors, based on uptake and elimination of 14C, increased in the order carbamazepine < diclofenac < fluoxetine and orlistat. LC-MS/MS and LC-FTMS indicated that the observed uptake in the fluoxetine and carbamazepine treatments was due to the parent compound but that diclofenac was degraded in the test system so uptake was due to unidentifiable transformation products. Comparison of our data with outputs of quantitative structure-activity relationship for estimating BCFs in worms showed that these models tend to overestimate pharmaceutical BCFs so new models are needed.

From gender benders to brain benders (and beyond!)

Article