Impact of the antidepressant Bupropion on the Dynamic Energy Budget of Daphnia magna.

Psychiatric drugs are considered among the emerging contaminants of concern in ecological risk assessment, due to their potential to disrupt homeostasis in aquatic organisms. Bupropion is an antidepressant that acts by selective reuptake inhibition of norepinephrine and dopamine. Little is known about this compound's effects on aquatic organisms, despite being detected in significant concentrations in both water and biota close to waste-water treatment plants and densely populated areas. Dynamic Energy Budget (DEB) models are flexible mechanistic tools that can be applied to understand toxic effects and extrapolate individual responses to higher biological levels and under untested environmental conditions. In this work, we used the stdDEB-TKTD (an application of the DEB theory to ecotoxicology) approach to investigate the possible physiological mode of action of Bupropion on the model organism Daphnia magna. Next, Dynamic Energy Budget Individual-Based Models (DEB-IBM) were used to extrapolate the results to the population level and to predict the combined effects of Bupropion exposure and food availability on the daphnids. Our results revealed an increasing negative effect of this antidepressant on the reproduction and survival of the animals with increasing concentration (0.004, 0.058, 0.58 and 58 µM). At the population level, we found that even the lowest used doses of Bupropion could reduce the population density and its reproductive output. The impacts are predicted to be stronger under limited food conditions.

Subacute Assessment of the Toxicity and Antidepressant-Like Effects of Origanum Majorana L. Polyphenols in Swiss Albino Mice.

Origanum majorana L. is a plant commonly used in folk medicine to treat depression and several neurological disorders. This study aims to evaluate the antidepressant-like effect of the Origanum majorana L. polyphenols (OMP) obtained from the aerial parts using two different depression model tests: The forced swimming test (FST) and the tail suspension test (TST) in Swiss albino mice. The experiments were performed on days 1, 7, 14, and 21 with daily administration of different treatments. Two different doses were chosen for this study (50 and 100 mg/kg), and paroxetine was used as a positive control. Immobility as a consequence of the depression state was significantly reduced following the treatment with OMP, indicating an antidepressant effect. A subacute toxicity study was also performed following the Organization for Economic Co-operation and Development (OECD) Guidelines (407), showing no sign of toxicity for the studied doses. The phytochemical screening revealed the presence of 12 components, all belonging to polyphenols: Arbutin, rosmarinic acid, ursolic acid, quercetin-3-O-glucoside, quercetin-7-O-glucuronic acid, luteolin-7-O-glucoside, kaempferol-3-0-glucuronic acid, Kaempferol-3-0-pentose, caffeic acid, catechin, quercetin, and rutin. These findings suggest that O. majorana has interesting antidepressant-like properties, which deserve further investigation.

Changing tides: Adaptive monitoring, assessment, and management of pharmaceutical hazards in the environment through time.

Pharmaceuticals are ubiquitous contaminants in aquatic ecosystems. Adaptive monitoring, assessment, and management programs will be required to reduce the environmental hazards of pharmaceuticals of concern. Potentially underappreciated factors that drive the environmental dose of pharmaceuticals include regulatory approvals, marketing campaigns, pharmaceutical subsidies and reimbursement schemes, and societal acceptance. Sales data for 5 common antidepressants (duloxetine [Cymbalta], escitalopram [Lexapro], venlafaxine [Effexor], bupropion [Wellbutrin], and sertraline [Zoloft]) in the United States from 2004 to 2008 were modeled to explore how environmental hazards in aquatic ecosystems changed after patents were obtained or expired. Therapeutic hazard ratios for Effexor and Lexapro did not exceed 1; however, the therapeutic hazard ratio for Zoloft declined whereas the therapeutic hazard ratio for Cymbalta increased as a function of patent protection and sale patterns. These changes in therapeutic hazard ratios highlight the importance of considering current and future drivers of pharmaceutical use when prioritizing pharmaceuticals for water quality monitoring programs. When urban systems receiving discharges of environmental contaminants are examined, water quality efforts should identify, prioritize, and select target analytes presently in commerce for effluent monitoring and surveillance.

Comparison of the sensitivity of seven marine and freshwater bioassays as regards antidepressant toxicity assessment.

The hazards linked to pharmaceutical residues like antidepressants are currently a major concern of ecotoxicology because they may have adverse effects on non-target aquatic organisms. Our study assesses the ecotoxicity of three antidepressants (fluoxetine, sertraline and clomipramine) using a battery of marine and freshwater species representing different trophic levels, and compares the bioassay sensitivity levels. We selected the following bioassays: the algal growth inhibition test (Skeletonema marinoi and Pseudokirchneriella subcapitata), the microcrustacean immobilization test (Artemia salina and Daphnia magna), development and adult survival tests on Hydra attenuata, embryotoxicity and metamorphosis tests on Crassostrea gigas, and in vitro assays on primary cultures of Haliotis tuberculata hemocytes. The results showed high inter-species variability in EC50-values ranging from 43 to 15,600 µg/L for fluoxetine, from 67 to 4,400 µg/L for sertraline, and from 4.70 µg/L to more than 100,000 µg/L for clomipramine. Algae (S. marinoi and P. subcapitata) and the embryo-larval stages of the oyster C. gigas were the most sensitive taxa. This raises an issue due to their ecological and/or economic importance. The marine crustacean A. salina was the least sensitive species. This difference in sensitivity between bioassays highlights the importance of using a test battery.

Assessment of cytotoxic and immunomodulatory properties of four antidepressants on primary cultures of abalone hemocytes (Haliotis tuberculata).

Pharmaceutical compounds like antidepressants found in surface waters raise concerns due to their potential toxicity on non-target aquatic organisms. This study aimed at investigating the in vitro cytotoxicity and immunomodulatory properties of four common antidepressants, namely Amitriptyline, Clomipramine, Citalopram and Paroxetine, on primary cultures of abalone hemocytes (Haliotis tuberculata), after 48 h-exposure. Effects on immunocompetence (phagocytosis, levels of reactive oxygen species, esterase activity and lysosomal membrane destabilization) were assessed. Results obtained by MTT assays revealed that acute toxicity is unlikely to occur in the environment since the LC50s of the four antidepressants are at the mg/L level. The different immunological endpoints displayed a biphasic response, with an increase at the lowest concentration (i.e. 1 µg/L) followed by a decrease at higher concentrations. Overall, Amitriptyline and Clomipramine, the two tricyclic antidepressants, had higher immunomodulatory capacities than the two selective serotonin reuptake inhibitors Citalopram and Paroxetine. Amitriptyline was the most potent and Citalopram the least potent drug in altering immune function in H. tuberculata.

Assessment of biomarkers of drug-induced kidney injury in cynomolgus monkeys treated with a triple reuptake inhibitor.

Drug-induced kidney injury (DIKI) results in attrition during drug development; new DIKI urinary biomarkers offer potential to detect and monitor DIKI progression and regression, but frequently only in rats. The triple reuptake inhibitor (TRI) PRC200-SS represents a new class of antidepressants that elevate synaptic levels of serotonin, norepinephrine, and dopamine and is expected to produce more rapid onset and better antidepressant efficacy than single or dual inhibitors. Although preclinical studies and recent clinical trials lend support to this concept of superior efficacy for TRIs, there is little information on the safety profile of this class of compounds. Using histopathology and DIKI biomarkers, in single- and repeat dose toxicological studies in cynomolgus monkeys, PRC200-SS demonstrated dose-proportional kidney toxicity. Characterization of the histopathological lesions, using a combination of immunohistochemistry (IHC) and urinary biomarker analysis, indicated that the compound is a distal tubule and collecting duct toxicant. Segment specificity for the lesions was shown using a newly developed triple IHC combination method with antibodies against calbindin D28, aquaporin 2, and aquaporin 1. Urinary biomarker analyses, using multiplex immunoassays, confirmed a dose-proportional increase in the excretion of calbindin D28 and clusterin in compound-treated monkeys with levels returning to baseline during the drug-free recovery period. These results constitute the validation of distal nephron DIKI biomarkers in the cynomolgus monkey and demonstrate the utility of calbindin D28 and clusterin to monitor the progression of distal nephron DIKI, representing potential early biomarkers of DIKI for the clinic.

Assessment of 5-hydroxytryptamine efflux in rat brain during a mild, moderate and severe serotonin-toxicity syndrome.

Serotonin (5-hydroxytryptamine; 5-HT)-toxicity syndrome, an iatrogenic brain disorder induced by excessive efflux of 5-HT, has received much attention because of increasing incidents of serotonergic antidepressants. However, the neural mechanism by which extracellular 5-HT is elevated to a toxic level for the syndrome remains to be determined. The goal of the present study was to test the hypothesis that extracellular 5-HT is composed of two component effluxes responsible for distinct aspects of the syndrome. The first set of experiments was to characterize the syndrome by measuring changes in neuromuscular signs, body-core temperature and mortality rate. Our results indicate that the syndrome severity can be categorized into mild, moderate and severe levels. The second set of experiments was to determine a threshold of extracellular 5-HT for induction of each level of the syndrome. Our results demonstrate that there were an 11-fold increase in the mild syndrome and an over 55-fold increase in the severe syndrome. In the last series of experiments, the excessive increases in 5-HT were pharmacologically separated into primary and secondary component effluxes with the 5-HT2A receptor antagonists cyproheptadine and ketanserin and NMDA receptor antagonist (+)-MK-801. Our results suggest that the primary component efflux was caused by direct drug effects on 5-HT biosynthetic and metabolic pathways and secondary efflux ascribed to indirect drug effect on a positive-feedback circuit involving 5-HT2A and NMDA receptors. In summary, the primary efflux could be an initial cause for the induction of the syndrome while the secondary efflux might involve deterioration of the syndrome.

Synthesis, toxicological and pharmacological assessment of morpholinooximes.

The synthesis, pharmacology and toxicology of four morpholine derivatives from 1-(2-arylmorpholino)-3-phenyl-3-propanonoxime and the synthesis of two anilides are described. The structures of the synthesized derivatives were proved by IR, 1H NMR and occasionally with 13C NMR. The acute toxicity of the compounds in mice was determined. A comparative pharmacological study of the in vivo effect on the central nervous system was realised by the following screening tests: pentobarbital induced sleeping time, locomotor activity and behaviour despair test for antidepressive activity. The most active compound was 1-(2-phenylmorpholino)-3-phenyl-3-propanonoxime (2b) which showed low toxicity and antidepressive activity at a dose of 1/10 LD50.

Synthesis, toxicological, and pharmacological assessment of derivatives of 2-aryl-4-(3-arylpropyl)morpholines.

The synthesis of nine original morpholine derivatives, i.e. 2-aryl-4-(3-arylpropyl)morpholines, is described. The structure of all synthesised derivatives was proved by IR and 1H-NMR, and some of them by 13C-NMR. Acute toxicity studies of the compounds were performed on mice. A comparative pharmacological study of the in vivo effects on the central nervous system was undertaken using the screening tests: hexobarbital induced sleeping time: locomotor activity; and behaviour despair (for antidepressive activity). The most active compound 4-(2-benzoylethyl)-2-phenyl-3-methyl) morpholine 4e was studied for MAO-A and MAO-B inhibition in vitro in rat brain mitochondria preparations.

Assessment of the anticholinergic effects of antidepressants in a single-dose cross-over study of salivation and plasma levels.

In order to evaluate the anticholinergic effect of antidepressant drugs, 11 healthy volunteers were given single oral doses of reference drug, test drugs or placebo on a double-blind basis at weekly intervals. The doses corresponded to average daily patient medications. Spontaneous whole mouth and parotid salivation, and plasma levels of drug and possible metabolites were measured 2, 6 and 10 h after drug administration. Moderate, statistically significant inhibition of salivation was found when nortriptyline, imipramine-N-oxide and mianserin were given. Less pronounced, but still statistically significant inhibition occurred after ingestion of nomifensine and zimelidine. The zimelidine effect was exclusively due to the metabolite norzimelidine, and the inhibition after imipramine-N-oxide was mainly due to the metabolite imipramine, but imipramine-N-oxide itself also had slight activity. Isocarboxazide and lithium had no effect on salivation. From these results and reported values of pharmacokinetic variables, the average level of anticholinergic activity during long-term treatment may be predicted: for mianserin and (nor-)zimelidine moderate inhibition of salivation, although less pronounced than with nortriptyline; for nomifensine no clinically significant effect; and for imipramine-N-oxide a negligible contribution from the unmetabolized drug.