Concentrations Of Amitriptyline Research Articles

The Relevance of Integrating CYP2C19 Phenoconversion Effects into Clinical Pharmacogenetics.

CYP2D6 and CYP2C19 functional status as defined by genotype is modulated by phenoconversion (PC) due to pharmacokinetic interactions. As of today, there is no data on the effect size of PC for CYP2C19 functional status. The primary aim of this study was to investigate the impact of PC on CYP2C19 functional status. Two patient cohorts (total n=316; 44.2±15.4 years) were investigated for the functional enzyme status of CYP2C19 applying two different correction methods (PCBousman, PCHahn&Roll) as well as serum concentration and metabolite-to-parent ratio of venlafaxine, amitriptyline, mirtazapine, sertraline, escitalopram, risperidone, and quetiapine. There was a decrease in the number of normal metabolizers of CYP2C19 and an increase in the number of poor metabolizers. When controlled for age, sex, and, in the case of amitriptyline, venlafaxine, and risperidone, CYP2D6 functional enzyme status, an association was observed between the CYP2C19 phenotype/functional enzyme status and serum concentration of amitriptyline, sertraline, and escitalopram. PC of CYP2C19 changes phenotypes but does not improve correlations with serum concentrations. However, only a limited number of patients received perturbators of CYP2C19. Studies with large numbers of patients are still lacking, and thus, it cannot be decided if there are minor differences and which method of correction to use. For the time being, PC is relevant in individual patients treated with CYP2C19-affecting drugs, for example, esomeprazole. To ensure adequate serum concentrations in these patients, this study suggests the use of therapeutic drug monitoring.

Amitriptyline inhibits bronchoconstriction and directly promotes dilatation of the airways

IntroductionThe standard therapy for bronchial asthma consists of combinations of acute (short-acting ß2-sympathomimetics) and, depending on the severity of disease, additional long-term treatment (including inhaled glucocorticoids, long-acting ß2-sympathomimetics, anticholinergics, anti-IL-4R antibodies). The antidepressant amitriptyline has been identified as a relevant down-regulator of immunological TH2-phenotype in asthma, acting—at least partially—through inhibition of acid sphingomyelinase (ASM), an enzyme involved in sphingolipid metabolism. Here, we investigated the non-immunological role of amitriptyline on acute bronchoconstriction, a main feature of airway hyperresponsiveness in asthmatic disease.MethodsAfter stimulation of precision cut lung slices (PCLS) from mice (wildtype and ASM-knockout), rats, guinea pigs and human lungs with mediators of bronchoconstriction (endogenous and exogenous acetylcholine, methacholine, serotonin, endothelin, histamine, thromboxane-receptor agonist U46619 and leukotriene LTD4, airway area was monitored in the absence of or with rising concentrations of amitriptyline. Airway dilatation was also investigated in rat PCLS by prior contraction induced by methacholine. As bronchodilators for maximal relaxation, we used IBMX (PDE inhibitor) and salbutamol (ß2-adrenergic agonist) and compared these effects with the impact of amitriptyline treatment. Isolated perfused lungs (IPL) of wildtype mice were treated with amitriptyline, administered via the vascular system (perfusate) or intratracheally as an inhalation. To this end, amitriptyline was nebulized via pariboy in-vivo and mice were ventilated with the flexiVent setup immediately after inhalation of amitriptyline with monitoring of lung function.ResultsOur results show amitriptyline to be a potential inhibitor of bronchoconstriction, induced by exogenous or endogenous (EFS) acetylcholine, serotonin and histamine, in PCLS from various species. The effects of endothelin, thromboxane and leukotrienes could not be blocked. In acute bronchoconstriction, amitriptyline seems to act ASM-independent, because ASM-deficiency (Smdp1−/−) did not change the effect of acetylcholine on airway contraction. Systemic as well as inhaled amitriptyline ameliorated the resistance of IPL after acetylcholine provocation. With the flexiVent setup, we demonstrated that the acetylcholine-induced rise in central and tissue resistance was much more marked in untreated animals than in amitriptyline-treated ones. Additionally, we provide clear evidence that amitriptyline dilatates pre-contracted airways as effectively as a combination of typical bronchodilators such as IBMX and salbutamol.ConclusionAmitriptyline is a drug of high potential, which inhibits acute bronchoconstriction and induces bronchodilatation in pre-contracted airways. It could be one of the first therapeutic agents in asthmatic disease to have powerful effects on the TH2-allergic phenotype and on acute airway hyperresponsiveness with bronchoconstriction, especially when inhaled.

(R)evolution of the Standard Addition Procedure for Immunoassays.

A new method to transfer the standard addition procedure for concentration determination to immunoassays with non-linear calibration curves was developed. The new method was successfully applied to simulated data and benchmarked against a state-of-the-art algorithm, showing a significantly improved performance with improvement factors between 2 and 192. The logit function was used to transform the immunoassay signal response of test samples spiked with known analyte concentrations. The relationship between logit(signal) and log-transformed estimated total analyte concentration is linear if the estimated total analyte concentration is correct. Finally, the new method was validated experimentally using different assays in varying, relevant complex matrices, such as serum, saliva, and milk. Different concentrations of testosterone and amitriptyline between 0.05 and 3.0 µg L-1 were quantified using a binding inhibition assay in combination with reflectometric interference spectroscopy (RIfS) as the transduction principle. The sample concentration was calculated using a numerical method. Samples could be quantified with recoveries between 70 and 118%. The standard addition method accounts for individual matrix interference on the immunoassay by spiking the test sample itself. Although the experiments were carried out using RIfS, the method can be applied to any immunoassay that meets the analytical requirements.

Systematic review on combination pharmacotherapy: methodological rigor but no pharmacology.

Systematic review on combination pharmacotherapy: methodological rigor but no pharmacology.

Tools to compare antibody gold nanoparticle conjugates for a small molecule immunoassay

Antibody gold nanoparticle conjugates as recognition elements are essential for the overall performance of lateral flow assays. When immobilizing antibodies on gold nanoparticles, the challenge is to prevent aggregation and to ensure that the antibodies are correctly oriented so that they remain functional and their paratopes remain accessible. There are many methods available, and it is difficult to decide which one to use. To help selecting the most appropriate conjugate production method, different synthetic routes of binding antibodies to gold nanoparticles are systematically investigated for the purpose of a quantitative lateral flow test for small molecules. The direct comparison of different conjugate syntheses shows how to select a suitable conjugate for a lateral flow assay. The syntheses examined are direct adsorption of antibody, direct adsorption of reduced antibody, covalent binding to polyethylene glycol linker, and binding via biotin-streptavidin interaction. The conjugates are characterized using UV-Vis spectroscopy and dynamic light scattering to determine their stability. Their performance on structured lateral flow test strips is examined using calibrations for different amitriptyline concentrations. It was shown that the best conjugate for quantification of amitriptyline was realized by direct adsorption of an UV-light irradiated antibody to gold nanoparticles. The methods employed can serve as a guide for selecting the most appropriate conjugate for an application and enhance the performance of lateral flow assays.Graphical abstract

Effects of the Antidepressant Amitriptyline on Juvenile Brown Trout and Their Modulation by Microplastics.

Pharmaceuticals such as antidepressants are designed to be bioactive at low concentrations. According to their mode of action, they can also influence non-target organisms due to the phylogenetic conservation of molecular targets. In addition to the pollution by environmental chemicals, the topic of microplastics (MP) in the aquatic environment came into the focus of scientific and public interest. The aim of the present study was to investigate the influence of the antidepressant amitriptyline in the presence and absence of irregularly shaped polystyrene MP as well as the effects of MP alone on juvenile brown trout (Salmo trutta f. fario). Fish were exposed to different concentrations of amitriptyline (nominal concentrations between 1 and 1000 µg/L) and two concentrations of MP (104 and 105 particles/L; <50 µm) for three weeks. Tissue cortisol concentration, oxidative stress, and the activity of two carboxylesterases and of acetylcholinesterase were assessed. Furthermore, the swimming behavior was analyzed in situations with different stress levels. Exposure to amitriptyline altered the behavior and increased the activity of acetylcholinesterase. Moreover, nominal amitriptyline concentrations above 300 µg/L caused severe acute adverse effects in fish. MP alone did not affect any of the investigated endpoints. Co-exposure caused largely similar effects such as the exposure to solely amitriptyline. However, the effect of amitriptyline on the swimming behavior during the experiment was alleviated by the higher MP concentration.

The effects of amitriptyline on human embryonic kidney cells growth and proliferation in vitro

Many studies have shown that antidepressants, including amitriptyline, can cause side effects on normal human cells, although the exact effects of amitriptyline on normal human cells are unclear. Accordingly, the present study investigated the cytotoxic effects of amitriptyline on the human embryonic kidney cell line. In this experimental-laboratory study, cells were divided into control group (no drug-treated) and amitriptyline treatment groups (treated with 39.06, 12.78, 156.25, 312.5, 625, 1250 and 2500 μg/ml of amitriptyline). MTT method was used to assay the cytotoxic effects of amitriptyline at 24 and 48 hours. The data were analyzed by one-way analysis of variance. Treatment with 39.06 and 78.12 μg/ml of amitriptyline for 24 hours had no significant effect on the viability of Hek-293 cells, but treatment with 156.25 μg/ml and higher concentrations of amitriptyline significantly reduced the viability of Hek-293 cells. Treatment of cells for 48 hours showed a significant reduction in cell viability at all concentrations. Amitriptyline has cytotoxic effects on normal human embryonic kidney cells and these effects depend on the dose and duration of treatment. The findings of this study can be of significant importance in terms of the side effects of amitriptyline consumption on normal cells of the human body.

Bioaccumulation potential of the tricyclic antidepressant amitriptyline in a marine Polychaete, Nereis virens

The continual discharge of pharmaceuticals from wastewater treatment plants (WWTPs) into the marine environment, even at concentrations as low as ng/L, can exceed levels that induce sublethal effects to aquatic organisms. Amitriptyline, a tricyclic antidepressant, is the most prescribed antidepressant in Norway, though the presence, potential for transport, and uptake by aquatic biota have not been assessed. To better understand the release and bioaccumulative capacity of amitriptyline, laboratory exposure studies were carried out with field-collected sediments. Influent and effluent composite samples from the WWTP of Stavanger (the 4th largest city in Norway) were taken, and sediment samples were collected in three sites in the proximity of this WWTP discharge at sea (WWTP discharge (IVAR), Boknafjord, and Kvitsøy (reference)). Polychaetes (Nereis virens) were exposed to field-collected sediments, as well as to Kvitsøy sediment spiked with 3 and 30 μg/g amitriptyline for 28 days. The WWTP influent and effluent samples had concentrations of amitriptyline of 4.93 ± 1.40 and 6.24 ± 1.39 ng/L, respectively. Sediment samples collected from IVAR, Boknafjord, and Kvitsøy had concentrations of 6.5 ± 3.9, 15.6 ± 12.7, and 12.7 ± 8.0 ng/g, respectively. Concentrations of amitriptyline were below the limit of detection in polychaetes exposed to sediment collected from Kvitsøy and IVAR, and 5.2 ± 2.8 ng/g in those exposed to Boknafjord sediment. Sediment spiked with 3 and 30 μg/g amitriptyline had measured values of 423.83 ± 33.1 and 763.2 ± 180.5 ng/g, respectively. Concentrations in worms exposed to the amended sediments were 9.5 ± 0.2 and 56.6 ± 2.2 ng/g, respectively. This is the first known study to detect measurable concentrations of amitriptyline in WWTP discharge in Norway and accumulation in polychaetes treated with field-collected sediments, suggesting that amitriptyline has the potential for trophic transfer in marine systems.

Effects of Pharmacokinetic Gene Variation on Therapeutic Drug Levels and Antidepressant Treatment Response.

Introduction Pharmacogenetic testing is proposed to minimize adverse effects when considered in combination with pharmacological knowledge of the drug. As yet, limited studies in clinical settings have investigated the predictive value of pharmacokinetic (pk) gene variation on therapeutic drug levels as a probable mechanism of adverse effects, nor considered the combined effect of pk gene variation and drug level on antidepressant treatment response. Methods Two depression cohorts were investigated for the relationship between pk gene variation and antidepressant serum concentrations of amitriptyline, venlafaxine, mirtazapine and quetiapine, as well as treatment response. For the analysis, 519 patients (49% females; 46.6±14.1 years) were included. Results Serum concentration of amitriptyline was associated with CYP2D6 (higher concentrations in poor metabolizers compared to normal metabolizers), of venlafaxine with CYP2C19 (higher concentrations in intermediate metabolizers compared to rapid/ultrarapid metabolizers) and CYP2D6 (lower metabolite-to-parent ratio in poor compared to intermediate and normal metabolizers, and intermediate compared to normal and ultrarapid metabolizers). Pk gene variation did not affect treatment response. Discussion The present data support previous recommendations to reduce starting doses of amitriptyline and to guide dose-adjustments via therapeutic drug monitoring in CYP2D6 poor metabolizers. In addition, we propose including CYP2C19 in routine testing in venlafaxine-treated patients to improve therapy by raising awareness of the risk of low serum concentrations in CYP2C19 rapid/ultrarapid metabolizers. In summary, pk gene variation can predict serum concentrations, and thus the combination of pharmacogenetic testing and therapeutic drug monitoring is a useful tool in a personalized therapy approach for depression.

The Antidepressants Amitriptyline and Paroxetine Induce Changes in the Structure and Functional Traits of Marine Nematodes

Increasing concentrations of the antidepressants amitriptyline and paroxetine were determined recently in marine habitats. However, their impact on marine biota is understudied, despite multiple undesirable effects they have on the environment. An important behavioral aspect that is increasingly measured following exposure to contaminants is the migration of fauna from contaminated areas. Hence, our aim was to better understand the migration pattern of marine meiobenthic fauna, but with a main focus on nematodes, following the exposure to both antidepressants, alone or in mixture. The experiment was carried out in microcosms, which comprised an uncontaminated upper and a lower contaminated compartment, where amitriptyline was added, alone or mixed with paroxetine, at concentrations of 0.4 and 40 µg L−1. The overall abundance of meiobenthic groups decreased significantly following exposure to amitriptyline in both compartments, a pattern augmented by the mixture with paroxetine. The migration of nematodes towards the upper compartments of microcosms was triggered by the level of contamination with antidepressants. As such, the species Terschellingia longicaudata showed no significant change in abundance, suggesting tolerance to both antidepressants. On the other hand, the abundances of nematode taxa Cyatholaimus prinzi, Calomicrolaimus sp., Calomicrolaimus honestus, Neochromadora sp., Chromadorina sp. and Chromadorina minor decreased significantly following the exposure to both antidepressants, even at low concentrations. At the end of the experiment, the dominant migratory nematodes belonged to deposit-feeders and omnivores-carnivores trophic guilds, with tail shapes of e/f types and body-sizes longer than 2 mm. Such functional traits increase their mobility in sediments and the chance to move away from contaminated habitats. Moreover, the sex ratio was imbalanced in the favor of males in contaminated lower compartments with mixtures of the lowest and highest concentrations of amitriptyline and paroxetine, suggesting that these drugs also affect the hormone system. In conclusion, the exposure to the antidepressants amitriptyline and paroxetine triggered important changes within nematode communities, as changes in taxonomic composition were a result of migration and survival of tolerant taxa, but equally acting on the hormone system and leading to unbalanced sex-ratio among the residents.

Prolonged coma due to amitriptyline overdose and genetic polymorphism: a case report

BackgroundReduced consciousness has a wide variety of possible causes, not infrequently being toxic in nature. An intoxication might be obvious, but in this paper an unexpected case with a tricyclic antidepressant is presented.Case presentationA 76-year-old caucasian female was found unconscious. Primary diagnostic evaluation, including a negative drugs of abuse test, did not give direction to any clear cause. Yet an intraventricular conductive disorder with widening of the QRS complex and electroencephalogram abnormalities did suggest a possible drug effect. Heteroanamnestic information led to the suspicion of an amitriptyline intoxication, which was confirmed by further laboratory analysis. The patient remained comatose for several days. High concentrations of amitriptyline indicated a large overdose of amitriptyline and, in combination with a cytochrome P450 2D6 poor metabolizer status, could explain the long persistence of her comatose state.ConclusionWe present a tricyclic antidepressant intoxication, where the patient is thought to have taken a large amount of amitriptyline at once, which, in combination with a cytochrome P450 2D6 poor metabolizer status, led to an unusual long persistence of her coma.

Assessing the binding interaction of polystyrene sulfonate with amitriptyline in healthy volunteers: a cross-over design-The BIND study.

Polystyrene sulfonate is used for binding potassium in patients with chronic kidney disease (CKD). Because of its binding properties, it can potentially bind other medications and thereby decrease their bioavailability and effectiveness. Amitriptyline, often used by CKD patients for neuropathic pain, shows significant binding to polystyrene sulfonate in vitro. The purpose of this study was to determine the effect of polystyrene sulfonate on the exposure of amitriptyline in vivo when taken concomitantly in healthy volunteers. We performed a prospective cross-over study in nine healthy volunteers. Participants were 18years of age or older, did not use any medication, and had no known allergy to amitriptyline or polystyrene sulfonate. Participants visited Deventer Teaching Hospital twice. Once they received a single dose of amitriptyline 50mg and once they received a single dose of both polystyrene sulfonate 15g and amitriptyline 50mg taken concomitantly, with a wash out period of at least 1week. After intake of the medication, six blood samples were collected, at 2, 3, 4, 5, 6, and 8h. Blood samples were analysed to determine maximum concentration (Cmax) and area under the curve 0-8h after intake (AUC0-8h). Difference in Cmax and AUC0-8h was analysed with a paired T-test or Wilcoxon signed rank test, depending on normality of the data. A p-value < 0.05 was considered statistically significant. Of the nine participants included, eight participants completed both visits to the hospital. Mean maximum concentration (Cmax) of amitriptyline was 35.61µgl-1 (95% CI 27.90-43.33µgl-1) when taken alone, compared to 9.25µgl-1 (95% CI 6.59-11.92µgl-1) when taken with polystyrene sulfonate (p < 0.001). Mean AUC0-8h of amitriptyline was 168.20µg × h l-1 (95% CI 139.95-196.45µg × h l-1) when taken alone and 45.78µg × h l-1 (95% CI 30.20-61.36µg × h l-1) when taken with polystyrene sulfonate (p < 0.0001). These results show a significant decrease in exposure of amitriptyline of approximately 75% when taken concomitantly with polystyrene sulfonate, thereby probably compromising therapy efficacy. Patients using both amitriptyline and polystyrene sulfonate should be informed to separate intake of these medications. NL8539 (17 April 2020).

The interplay between pharmacogenetics, concomitant drugs and blood levels of amitriptyline and its main metabolites.

Background: The research considers the impact of genotype-inferred variability on blood levels of amitriptyline and its main metabolites, as may be moderated by phenocopying. Patients & methods:CYP2D6 and CYP2C19 genotypes, and serum concentrations of amitriptyline, nortriptyline and hydroxymetabolites, were determined in 33 outpatients. Co-medications were reviewed to identify CYP inhibition risk. Results: CYP2C19 metabolizer status explained interpatient variation in nortriptyline to amitriptyline concentration ratios. The hydroxymetabolite to parent ratios increased with higher CYP2D6 activity scores and lower CYP2D6 inhibition risk. In patients at high CYP2D6 inhibition risk, the amitriptyline+ nortriptyline concentration was, on average, 52% above the higher end of expected ranges. Conclusion: Practical construal of pharmacogenetics and drug interactions tantamount to aberrant metabolism can facilitate patient-tailored use of the established drug.

Electrochemical sensor for tricyclic antidepressants with low nanomolar detection limit: Quantitative Determination of Amitriptyline and Nortriptyline in blood

Amitriptyline and its metabolite, Nortriptyline are commonly used tricyclic antidepressant (TCA) drugs that are electrochemically active. In this work, the performance characteristics of a plasticized PVC membrane-coated glassy carbon (GC) electrode are described for the voltammetric quantification of Amitriptyline and Nortriptyline in whole blood. The highly lipophilic Amitriptyline and Nortriptyline preferentially partition into the plasticized PVC membrane where the free drug is oxidized on the GC electrode. The concentrations of the drugs in the membrane are orders of magnitude larger than in the sample solution, resulting in superb limit of detection (LOD) of the membrane-coated voltammetric sensor: 3 nmol/L for Amitriptyline and 20 nmol/L for Nortriptyline. Conversely, hydrophilic components of the sample solution, e.g., proteins, the protein-bound fraction of the drugs, and electrochemically active small molecules are blocked from entering the membrane, which provides exceptional selectivity for the membrane-coated sensor and feasibility for the measurements of Amitriptyline in whole blood. In this work, the concentrations of Amitriptyline and Nortriptyline were determined in whole blood using the sensor and the results of our analysis were compared to the results of the standard HPLC-MS method. Based on our experience, the one-step voltammetric methods with the membrane-coated sensor may become a real alternative to the significantly more complex HPLC-MS analysis.

Nanoscale materials in the composition of biosensors for the determination of amitriptyline

Biosensor devices including hybrid nanostructures as modifiers of transducer surfaces meet current requirements for the methods of research and determination of drugs, including antidepressants. The fea­tures of amperometric monoamine oxidase biosensors based on printed carbon electrodes modified with nanocomposite compositions C60 / cobalt nanoparticles/amino derivative of polyether polyol of the second generation/chitosan nanocomposite structures used for the detection of tricyclic antidepressant amitriptyline are considered. The choice of the best modifier was made proceeding from the data of transmission electron microscopy, scanning electron microscopy, electrochemical impedance spectroscopy, and differential pulse voltammetry. When developing the biosensor, conditions for depositing the composite composition of cobalt nanoparticles/amino derivative of polyether polyol on the electrode surface were varied: electrochemical deposition, sequential layer-by-layer deposition, and deposition of the mixture. The peak of electrochemical oxidation of hydrogen peroxide, which is formed during the enzymatic reaction of serotonin oxidation under the action of monoamine oxidase was used as an analytical signal of the biosensor. The principle of the biosensor action is based on the inhibitory effect of amitriptyline on the catalytic activity of immobilized monoamine oxidase. The proper choice of a modifier and optimal working conditions provided the range of detectable concentrations of amitriptyline: 1 x 10-4 - 1 x 10-8 M, the lower limit of the determined content at a level of 5 x 10-9 M for monoamine oxidase biosensor. Comparison of the results on the amitriptyline content determination in the pharmaceutical preparation and urine obtained using the monoamine oxidase biosensor and polarization fluorescence immunoassay (dilution of the tracer 1:32, dilution of antibodies 1:128, the range of working concentrations 5 x 10 -8 — 5 x 10-9 M), well-proven in the quantitative determination of medicinal substance, confirmed the correctness of the results obtained.

Development of a molecular imprinted electrochemiluminescence sensor for amitriptyline detection: From MD simulations to experimental implementation

Amitriptyline (AMT) frequent presence in environmental waters reflects the continuous consumption growth and raises issues on the importance of its monitorization. In this work, a sensitive and selective electrochemiluminescence (ECL) sensor was constructed using molecularly imprinted polymer (MIP) recognition element for AMT detection. Molecular dynamics (MD) simulations were performed to select the best functional monomer. Precipitation polymerization was followed to prepare the MIP microspheres using methacrylic acid (MAA) as functional monomer, ethylene glycol methacrylate (EGDMA) as crosslinker and chloroform (CHL) as solvent. The MIP sensor was then prepared on a low cost and disposable screen-printed electrodes (SPCEs), previously modified with single-walled carbon nanotubes (SWCNTs), by drop coating a solution containing the MIP microspheres synthesized. The mechanism of detection was based in the system Ru(bpy)32+/AMT, where AMT acts as co-reactor of Ru(bpy)32+ ECL. Several parameters controlling the preparation process of the sensor and AMT detection were optimised. The MIP/SWCNTs/SPCE ECL sensor showed good analytical performance with a linear correlation between ECL signal and the AMT concentration ranging from 0.1 to 200 µM (R2 = 0.9991). The limits of detection (LOD) and quantification (LOQ) were found to be 0.4 µM (S/N=3) and 1.5 µM (S/N = 10), respectively. The MIP ECL sensor displayed good selectivity to recognise AMT molecules when compared with analoge structures and it was successfully applied in real water samples with good recovery values (90 to 112%). The developed MIP ECL sensor is suitable for integration with portable devices for AMT detection in environmental waters.

Integrated biological response to environmentally-relevant concentration of amitriptyline in Sparus aurata

Amitriptyline (AMI) is a commonly tricyclic antidepressant to treat depression, anxiety, and other conditions. Like many other pharmaceuticals, AMI and its by-products are incompletely removed during wastewater treatment and therefore they are released to rivers, estuaries and coastal waters. The presence of this kind of compounds in the water environment may involve a negative impact on non-target aquatic organisms at relatively low concentrations. However, the knowledge of AMI effects on aquatic organisms in the environment is scarce. Thus, the objective of this work is to determine the effects of environmentally-relevant concentrations of AMI on biological responses at biochemical and cellular levels in marine teleost. Gilt-head seabream (S. aurata) were exposed to AMI for 7 days at 0.2 μg/L in an open flow system and a battery of biomarkers were investigated: acetylcholinesterase, catalase, superoxide dismutase, glutathione S-transferase, cytochrome C oxidase, P450 CYP1A1 ethoxyresorufin (O) dealkylation, and lysosomal biomarkers. Biomarkers were integrated as IBR/n (biological response index). Overall, it can be concluded that AMI exposure at environmentally-relevant concentration induces significant biological responses to stress in marine teleost, especially in lysosomal biomarkers. However, further research is needed about the effects of AMI and other pharmaceuticals on biomarkers in non-targeted species, to raise the knowledge about the toxicity of this type of emerging pollutants.

Amitriptyline Decreases GABAergic Transmission in Basal Forebrain Neurons Using an Optogenetic Model of Aging.

The antidepressant drug amitriptyline is used in the treatment of clinical depression and a variety of neurological conditions such as anxiety, neuropathic pain disorders and migraine. Antidepressants are associated with both therapeutic and untoward effects, and their use in the elderly has tripled since the mid-1990s. Because of this widespread use, we are interested in testing the acute effects of amitriptyline on synaptic transmission at therapeutic concentrations well below those that block voltage-gated calcium channels. We found that 3 μM amitriptyline reduced the frequency of spontaneous GABAergic inhibitory postsynaptic currents (IPSCs) and reduced quantal content in mice at ages of 7–10 mo. and 23–25 mo., suggesting a presynaptic mechanism of action that does not diminish with age. We employed a reduced synaptic preparation of the basal forebrain (BF) and a new optogenetic aging model utilizing a bacterial artificial chromosome (BAC) transgenic mouse line with stable expression of the channelrhodopsin-2 (ChR2) variant H134R specific for GABAergic neurons [VGAT-ChR2(H134R)-EYFP]. This model enables optogenetic light stimulation of specific GABAergic synaptic terminals across aging. Age-related impairment of circadian behavior was used to confirm predictable age-related changes associated with this model. Our results suggest that low concentrations of amitriptyline act presynaptically to reduce neurotransmitter release and that this action is maintained during aging.

Role of serum amitriptyline concentration and CYP2C19 polymorphism in predicting the response to low-dose amitriptyline in irritable bowel syndrome

BackgroundLow-dose amitriptyline (AMT) is an effective treatment for diarrhea-dominant irritable bowel syndrome (IBS-D). Its efficacy depends upon its serum concentration and the patient's CYP2C19 genotype. AimsTo identify the association between serum AMT and nortriptyline (NT) concentration and CYP2C19 polymorphism and the clinical response in IBS-D patients. MethodsNinety IBS-D patients were treated of AMT for 6 weeks. Efficacy was evaluated by the results of the Adequate Relief question each week and an IBS severity scoring system (IBS-SSS) at 0, 3, and 6 weeks. CYP2C19 genotyping was performed by direct sequencing. AMT and NT steady-state serum concentrations were detected by high-performance liquid chromatography. ResultsThe CYP2C19 polymorphism exhibited a significant influence on the NT serum concentration but did not predict the clinical efficacy of AMT for treating IBS-D. The NT steady-state and dose-corrected serum concentrations were significantly correlated with an improvement in the IBS-SSS score after 6 weeks, whereas the AMT serum concentration was not correlated with clinical improvement. The cut-off NT steady-state serum concentration of 2.91 ng/ml may help distinguish responders from non-responders. ConclusionsNT serum concentration but not CYP2C19 polymorphism may be correlated with the clinical efficacy of AMT for treating IBS-D, and such a response may occur at the upper NT threshold of 2.91 ng/ml.

Роль рианодиновых и IP 3 -рецепторов в генерации кальциевых ответов, вызываемых трициклическими антидепрессантами в нейронах неокортекса крысы

Tricyclic antidepressants, in particular amitriptyline (ATL) and desipramine (DES), are currently used to treat depression and chronic pain of various origins, in which NMDA receptor dysfunctions play an important role. The effect of therapeutic concentrations of ATL on calcium-dependent desensitization of NMDA receptors, driven by the level of free calcium in the cytoplasm, is well-known. In addition, in cardiomyocytes, ATL and DES can cause the release of calcium into the cytoplasm from intracellular stores by opening inositol-3-phosphate (IP3R) and / or ryanodine receptors (RyR) channels. The aspect of the effect of these drugs on neurons remains poorly understood. We studied the dependence of the calcium response to DES and ATL on the activation of IP3R and RyR of the endoplasmic reticulum and mitochondria using rat neocortex neurons in primary culture. Short-term (30 s) paired (5 min interval) applications of 200 μM DES or 200 μM ATL induce similar magnitude calcium responses in cortical neurons. The use of RyR and IP3R antagonists showed that responses to ATL are blocked by the IP3R antagonist 2-APB (100 μM), while responses to DES are blocked by ryanodine, the RyR antagonist (100 nM). Since intracellular distribution of RyR and IP3R is not homogenous, it can be assumed that DES and ATL stimulate calcium release from different calcium depots, representing segments of the reticulum or mitochondria. In addition, ATL and DES, being channel blockers of NMDA receptors, inhibited calcium entry from outside the cell via activated NMDA receptors. Considering the high concentrations of DES and ATL (more than 100 μM) required to stimulate the release of deposited calcium in neurons, it seems unlikely that such effects participate their therapeutic action. However, the found specificity of DES and ATL for RyR and IP3R, respectively, can be used as a tool for experimental purposes.