Escitalopram, the S-(+)-enantiomer of citalopram, is a selective serotonin reuptake inhibitor with potent effects in animal models predictive of antidepressant and anxiolytic activities

Acute anxiogenic effects of escitalopram are associated with mild alterations in D-amphetamine-induced behavior and social approach evoked by playback of 50-kHz ultrasonic vocalizations in rats

Rats communicate through auditory signals in the ultrasonic range, so-called ultrasonic vocalizations (USV). Short, high-frequency 50-kHz USV are associated with positive affective states and are emitted in appetitive situations, often rewarding social interactions, such as rough-and-tumble play and mating. Exaggerated levels of 50-kHz USV emission can be observed in response to psychostimulants, most notably d-amphetamine (AMPH). There is robust evidence suggesting that 50-kHz USV serve as affiliative signals and help to maintain or re-establish social proximity. A key neurotransmitter involved in behavioral regulation is serotonin (5-hydroxytryptamine, 5-HT). This includes both, the regulation of anxiety-related behavior and ultrasonic communication. Here, we show that acute treatment with the selective 5-HT reuptake inhibitor (SSRI) escitalopram (ESC) leads to increased anxiety-related behavior in the elevated plus maze and tested whether such acute anxiogenic effects of ESC result in alterations in ultrasonic communication in sender and/or receiver. To this aim, we conducted a dose-response study in male rats and assessed AMPH-induced hyperactivity and 50-kHz ultrasonic calling in the sender and social approach behavior evoked by playback of pro-social 50-kHz USV in the receiver. Acute ESC treatment affected both, sender and receiver. This was reflected in a lack of AMPH-induced changes in acoustic features of 50-kHz USV and absence of social exploratory behavior evoked by 50-kHz USV playback, respectively. Albeit the SSRI effects were relatively mild, this supports the notion that the 5-HT system is involved in the regulation of a key aspect of the social behavior repertoire of rodents, namely socio-affective communication through 50-kHz USV.

Transcriptional signatures of early-life stress and antidepressant treatment efficacy

Individuals with a history of early-life stress (ELS) tend to have an altered course of depression and lower treatment response rates. Research suggests that ELS alters brain development, but the molecular changes in the brain following ELS that may mediate altered antidepressant response have not been systematically studied. Sex and gender also impact the risk of depression and treatment response. Here, we leveraged existing RNA sequencing datasets from 1) blood samples from depressed female- and male-identifying patients treated with escitalopram or desvenlafaxine and assessed for treatment response or failure; 2) the nucleus accumbens (NAc) of female and male mice exposed to ELS and/or adult stress; and 3) the NAc of mice after adult stress, antidepressant treatment with imipramine or ketamine, and assessed for treatment response or failure. We find that transcriptomic signatures of adult stress after a history of ELS correspond with transcriptomic signatures of treatment nonresponse, across species and multiple classes of antidepressants. Transcriptomic correspondence with treatment outcome was stronger among females and weaker among males. We next pharmacologically tested these predictions in our mouse model of early-life and adult social defeat stress and treatment with either chronic escitalopram or acute ketamine. Among female mice, the strongest predictor of behavior was an interaction between ELS and ketamine treatment. Among males, however, early experience and treatment were poor predictors of behavior, mirroring our bioinformatic predictions. These studies provide neurobiological evidence for molecular adaptations in the brain related to sex and ELS that contribute to antidepressant treatment response.

Advances in Pharmacotherapy for Pediatric Anxiety Disorders

The evidence base for psychopharmacologic interventions in children and adolescents with anxiety disorders has significantly increased, and our understanding of the relative efficacy and tolerability of interventions has expanded contemporaneously. Selective serotonin reuptake inhibitors (SSRIs) are the first-line pharmacologic treatment for pediatric anxiety due to their robust efficacy although other agents may have efficacy. This review summarizes the data concerning the use of SSRIs, serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants, atypical anxiolytics (eg, 5HT_1A agonists, alpha agonists), and benzodiazepines in pediatric anxiety disorder cases (ie, generalized anxiety disorder, separation anxiety disorder, social anxiety disorder, and panic disorder). The extant data suggest that SSRIs and SNRIs are effective and well tolerated. SSRIs as monotherapy and SSRIs + cognitive behavioral therapy reduce symptoms in youth with anxiety disorders. However, randomized controlled trials do not suggest efficacy for benzodiazepines or the 5HT_1A agonist, buspirone, in pediatric anxiety disorder cases.

Effects of Three Serotonin Reuptake Inhibitors on Sign-Tracking in Male Sprague-Dawley Rats

Sign-tracking is a behavior with relevance to cue-triggered relapse addiction, a Pavlovian conditioned approach behavior directed at the conditioned stimulus. The study examined one strategy for reducing the magnetic pull of drug-associated conditioned stimuli, using selective serotonin reuptake inhibitors (SSRIs) citalopram (0, 10, and 20 mg/kg), escitalopram (0, 10, and 20 mg/kg) and fluoxetine (0, 5, and 10 mg/kg). Male Sprague-Dawley rats were first trained in a standard sign-tracking task and then acutely administered these drugs in a series of three experiments. In each study, it was found that measures of sign-tracking were reduced, although effects on goal-tracking were different between drugs. This study provides evidence that administration of serotonergic antidepressants is effective in reducing sign-tracking and may have some efficacy in preventing cue-triggered relapse.

Dorsal raphe serotonergic neurons preferentially reactivate dorsal dentate gyrus cell ensembles associated with positive experience

Major depressive disorder (MDD) is among the most common mental illnesses. Serotonergic (5-HT) neurons are central to the pathophysiology and treatment of MDD. Repeatedly recalling positive episodes is effective for MDD. Stimulating 5-HT neurons of the dorsal raphe nucleus (DRN) or neuronal ensembles in the dorsal dentate gyrus (dDG) associated with positive memories reverses the stress-induced behavioral abnormalities. Despite this phenotypic similarity, their causal relationship is unclear. This study revealed that the DRN 5-HT neurons activate dDG neurons; surprisingly, this activation was specifically observed in positive memory ensembles rather than neutral or negative ensembles. Furthermore, we revealed that dopaminergic signaling induced by activation of DRN 5-HT neurons projecting to the ventral tegmental area mediates an increase in active coping behavior and positive dDG ensemble reactivation. Our study identifies a role of DRN 5-HT neurons as specific reactivators of positive memories and provides insights into how serotonin elicits antidepressive effects.

Citalopram in the treatment of elderly chronic heart failure combined with depression: A systematic review and meta-analysis

Background

Depression is an independent factor to predict the hospitalization and mortality in the chronic HF patients. Citalopram is known as an effective drug for depression treatment. Currently, there is no specific recommendation in the HF guidelines for the treatment of psychological comorbidity. In recent years, many studies have shown that the citalopram may be safe in treating of chronic HF with depression.

Objective

To evaluate the efficacy and safety of the citalopram in the treatment of elderly chronic HF combined with depression.

Methods

PubMed, EMBASE, Cochrane, Web of Science, CNKI, VIP, CBM, and Wanfang were searched from their inception to May 2022. In the treatment of elderly chronic HF combined with depression, randomized controlled studies of the citalopram were included. Independent screening and extraction of data information were conducted by two researchers, and the quality was assessed by the Cochrane bias risk assessment tool. Review manager 5.4.1 was employed for statistical analysis.

Results

The results of meta-analysis prove that the citalopram treatment for depressed patients with chronic HF has a benefit for HAMD-24 (MD: -8.51, 95% CI: -10.15 to -6.88) and LVEF (MD: 2.42, 95% CI: 0.51 to 4.33). Moreover, the score of GDS decreases, and NT-proBNP (MD: -537.78, 95% CI: -718.03 to -357.54) is improved. However, the comparison with the control group indicates that there is no good effect on HAMD-17 (MD: -5.14, 95% CI: -11.60 to 1.32), MADRS (MD: -1.57, 95% CI: -3.47 to 0.32) and LVEDD (MD: -1.45, 95% CI: -3.65 to -0.76). No obvious adverse drug reactions were observed.

Conclusion

Citalopram treatment for depressed patients with chronic HF has a positive effect on LVEF and NT-proBNP. It can alleviate HAMD-24 and GDS, but the relative benefits for LVEDD, HAMD-17 and MADRS still need to be verified.Systematic Review Registration: PROSPERO [CRD42021289917].

A Review of Clinical Studies Assessing the Therapeutic Efficacy of Escitalopram: A Step Towards Development

BACKGROUND

Major depression is a debilitating, sometimes fatal disorder, deteriorating the quality of life and well-being. Escitalopram showed highly selective and dose-dependent inhibitory activity on human serotonin transport. Selective serotonin reuptake inhibitors (SSRIs) are the first-line drugs to manage major depressive disorder (MDD).

OBJECTIVE

The objective of this study is to explore the therapeutic potential of escitalopram, a clinically approved drug to manage MDD and panic disorders.

METHODS

It emphasizes comparative and clinical trial studies with several pharmacological targets reviewed from the data available on PubMed, Science Direct, Clinicaltrails.gov, and from many reputed foundations.

RESULTS

To highlight the clinical efficacy, safety, recent development, and stable formulation of escitalopram with an increased bioavailability profile. Evidence-based on the available clinical and pharmacoeconomic data, escitalopram represents an effective first-line treatment option for MDD patients.

CONCLUSION

The present review highlights the placebo-controlled clinical studies and the recent development that can be helpful for further research perspectives.

Stereoselectivity in the Membrane Transport of Phenylethylamine Derivatives by Human Monoamine Transporters and Organic Cation Transporters 1, 2, and 3

Stereoselectivity is well known and very pronounced in drug metabolism and receptor binding. However, much less is known about stereoselectivity in drug membrane transport. Here, we characterized the stereoselective cell uptake of chiral phenylethylamine derivatives by human monoamine transporters (NET, DAT, and SERT) and organic cation transporters (OCT1, OCT2, and OCT3). Stereoselectivity differed extensively between closely related transporters. High-affinity monoamine transporters (MATs) showed up to 2.4-fold stereoselective uptake of norepinephrine and epinephrine as well as of numerous analogs. While NET and DAT preferentially transported (S)-norepinephrine, SERT preferred the (R)-enantiomer. In contrast, NET and DAT showed higher transport for (R)-epinephrine and SERT for (S)-epinephrine. Generally, MAT stereoselectivity was lower than expected from their high affinity to several catecholamines and from the high stereoselectivity of some inhibitors used as antidepressants. Additionally, the OCTs differed strongly in their stereoselectivity. While OCT1 showed almost no stereoselective uptake, OCT2 was characterized by a roughly 2-fold preference for most (R)-enantiomers of the phenylethylamines. In contrast, OCT3 transported norphenylephrine and phenylephrine with 3.9-fold and 3.3-fold preference for their (R)-enantiomers, respectively, while the para-hydroxylated octopamine and synephrine showed no stereoselective OCT3 transport. Altogether, our data demonstrate that stereoselectivity is highly transporter-to-substrate specific and highly diverse even between homologous transporters.

Fluoxetine reverses hyperactivity of anterior cingulate cortex and attenuates chronic stress-induced hyperalgesia

Somatic symptom disorder (SSD), which occurs in about 5-7 percent of the adult population, involves heightened physical and emotional sensitivity to pain. However, its neural mechanism remains elusive and thus hinders effective clinical intervention. In this study, we employed chronic restraint stress (CRS)-induced hyperalgesia as a mouse model to investigate the neural mechanism underlying SSD and its pharmacological treatment. We found that CRS induced hyperactivity of anterior cingulate cortex (ACC), whereas chemogenetic inhibition of such hyperactivity could prevent CRS-induced hyperalgesia. Systematic application and ACC local infusion of fluoxetine alleviated CRS-induced hyperalgesia. Moreover, we found that fluoxetine exerted its anti-hyperalgesic effects through inhibiting the hyperactivity of ACC and upregulating 5-HT1A receptors. Our study thus uncovers the functional role of 5-HT signaling in modulating pain sensation and provides a neural basis for developing precise clinical intervention for SSD.

Systematic review and meta-analysis on the therapeutic reference range for escitalopram: Blood concentrations, clinical effects and serotonin transporter occupancy

INTRODUCTION

A titration within a certain therapeutic reference range presupposes a relationship between the blood concentration and the therapeutic effect of a drug. However, this has not been systematically investigated for escitalopram. Furthermore, the recommended reference range disagrees with mean steady state concentrations (11-21 ng/ml) that are expected under the approved dose range (10-20 mg/day). This work systematically investigated the relationships between escitalopram dose, blood levels, clinical effects, and serotonin transporter occupancy.

METHODS

Following our previously published methodology, relevant articles were systematically searched and reviewed for escitalopram.

RESULTS

Of 1,032 articles screened, a total of 30 studies met the eligibility criteria. The included studies investigated escitalopram blood levels in relationship to clinical effects (9 studies) or moderating factors on escitalopram metabolism (12 studies) or serotonin transporter occupancy (9 studies). Overall, the evidence for an escitalopram concentration/effect relationship is low (level C).

CONCLUSION

Based on our findings, we propose a target range of 20-40 ng/ml for antidepressant efficacy of escitalopram. In maintenance treatment, therapeutic response is expected, when titrating patients above the lower limit. The lower concentration threshold is strongly supported by findings from neuroimaging studies. The upper limit for escitalopram's reference range rather reflects a therapeutic maximum than a tolerability threshold, since the incidence of side effects in general is low. Concentrations above 40 ng/ml should not necessarily result in dose reductions in case of good clinical efficacy and tolerability. Dose-related escitalopram concentrations in different trials were more than twice the expected concentrations from guideline reports.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=215873], identifier [CRD42020215873].

Behavioral, cortical and autonomic effects of single-dose escitalopram on the induction and regulation of fear and disgust: Comparison with single-session psychological emotion regulation with reappraisal

INTRODUCTION

Adaptive and successful emotion regulation, the ability to flexibly exert voluntary control over emotional experience and the ensuing behavior, is vital for optimal daily functioning and good mental health. In clinical settings, pharmacological and psychological interventions are widely employed to modify pathological emotion processing and ameliorate its deleterious consequences.

METHODS

In this study, we investigated the acute effects of single-dose escitalopram on the induction and regulation of fear and disgust in healthy subjects. Furthermore, we compared these pharmacological effects with psychological emotion regulation that utilized a cognitive strategy with reappraisal. Emotion induction and regulation tasks were performed before and 4 h after ingestion of placebo or 10 mg escitalopram in a randomized, double-blind design. The International Affective Picture System (IAPS) was used as a source of images, with threat-related pictures selected for fear and disease and contamination-related pictures for disgust. Behavioral data, electrodermal activity (EDA), and functional near-infrared spectroscopy (fNIRS) recordings were collected.

RESULTS

Escitalopram significantly reduced emotion intensity for both fear and disgust during emotion induction, albeit with differing electrodermal and hemodynamic activity patterns for the two negative emotions. At rest, i.e., in the absence of emotive stimuli, escitalopram increased sympathetic activity during the fear but not during the disgust experiments. For both fear and disgust, emotion regulation with reappraisal was more effective in reducing emotion intensity compared to pharmacological intervention with escitalopram or placebo.

DISCUSSION

We concluded that emotion regulation with reappraisal and acute administration of escitalopram, but not placebo, reduce emotion intensity for both fear and disgust, with cognitive regulation being significantly more efficient compared to pharmacological regulation under the conditions of this study. Results from the fNIRS and EDA recordings support the concept of differential mechanisms of emotion regulation that could be emotion-specific.

Impact of gender, depression severity and type of depressive episode on efficacy and safety of escitalopram: an observational study on major depressive disorder patients in southern India

Background

Antidepressant response is a complex trait influenced by clinical, demographic and genetic factors.

Objectives

To explore the influences of baseline depression severity, gender and type of depressive episode on efficacy and safety of escitalopram (10–20 mg/day) in South Indian patients with major depressive disorder (MDD).

Methods

The study was conducted on 18–65-year-old patients (n = 151) suffering from a first or recurrent episode of MDD with a 17-item Hamilton Depression Rating Scale (HDRS-17) score of ≥ 18 at baseline. Efficacy assessments were done using HDRS-17, Montgomery-Asberg Depression Rating Scale (MADRS), and Clinical Global Impression (CGI) at baseline and weeks 4, 8 and 12. Patients were monitored for adverse drug reactions (ADRs). Clinical outcomes were compared among various groups based on gender, type of depressive episode (first or recurrent episode) and baseline HDRS-17 scores (moderate depression—score between 17 and 23; severe depression—score ≥ 24).

Results

Among the 148 subjects who completed the 12-week study, 43.9% and 42.6% achieved response and remission, respectively. The decline in HDRS-17 and MADRS scores from baseline was significant (p value < 0.05) at all follow-up visits and a similar pattern was seen with CGI. Efficacy outcomes were better in the moderate baseline depression group compared with severe depression. There were no associations of efficacy with gender and type of depressive episode. A total of 247 adverse drug reactions (ADR) were reported and 119 (80.41%) subjects experienced at least one ADR during the study period. No serious ADR was reported. Male patients experienced more ADRs compared with females. The safety profile of escitalopram was similar across various groups based on baseline depression severity and type of depressive episode.

Conclusion

The study revealed that escitalopram is efficacious in south Indian MDD patients with a favourable safety profile. The efficacy was influenced by baseline depression severity whereas more ADRs were reported by male patients.

Sustained escitalopram administration affects glucose metabolism in the rat brain

Escitalopram is a selective serotonin reuptake inhibitor (SSRIs) antidepressant, drug that is currently used as first-line agents for the treatment of depression and it is also used in the treatment of other psychiatric disorders. The main goal of this study was to identify which brain areas are affected by escitalopram administration. This study was carried out on male Wistar rats that received escitalopram daily over 14 days and that were studied by 2-deoxy-2[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG)-PET on the last day of treatment. Computed tomography (CT) images were acquired immediately before each PET scan and the main effects of drug administration were elucidated by Statistical Parametric Mapping. The results obtained indicated that repeated exposure to escitalopram increased metabolic activity in the retrosplenial and posterior cingulate cortices, while it decreased such activity in the ventral hippocampus, cerebellum, brainstem and midbrain regions, including the raphe nuclei and ventral tegmental area. Therefore, repeated exposure to escitalopram alters the activity of several brain areas closely related to the serotonergic system, and previously identified as key regions in the antidepressant effect induced by SSRIs. Furthermore, some of the changes found, such as the dampened metabolism in the ventral tegmental area, are similar to changes that have been described after treating with other fast-acting antidepressant approaches.

An update on the treatment of premature ejaculation: A systematic review

To analyse the current therapeutic options for patients with premature ejaculation (PE) and highlight their mechanism(s) of action, effectiveness, advantages and limitations. A literature search was conducted using the PubMed database searching for articles exploring different PE treatment modalities. A Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) approach was used to report the results of the literature search. A total of 149 articles were included in this review. The currently available treatment methods for PE include behavioural therapy, local anaesthetics, tricyclic antidepressants, selective serotonin reuptake inhibitors, and selective phosphodiesterase inhibitors. Most PE treatments are either experimental or used off-label. New treatments are certainly warranted to overcome this exasperating sexual dysfunction.

Abbreviations: AIPE: Arabic Index of Premature Ejaculation; CNS: central nervous system; CYP: cytochrome P450; ED: erectile dysfunction; FDA: United States Food and Drug Administration; H1: histamine receptors; 5-HT: 5-hydroxytryptamine; IELT: The intravaginal ejaculation latency time; IPE: Index of Premature Ejaculation; M1: muscarinic receptors; OCD: obsessive–compulsive disorder; PDE5: phosphodiesterase type 5; PE: premature ejaculation; PEP: Premature Ejaculation Profile; PRO: patient-reported outcome; RCT: randomised controlled trial; SS: Severance Secret (cream); SSRIs: selective serotonin reuptake inhibitors; TCAs: tricyclic antidepressants

Selective LC-MS/MS determination of citalopram enantiomers and application to a pharmacokinetic evaluation of generic and reference formulations

Two methods using LC-MS/MS were validated to quantify citalopram (CTP) racemate [(R/S)-CTP] and the enantiomers (R)-CTP and (S)-CTP in human plasma, respectively. Paroxetine hydrochloride was used as the internal standard, and samples were extracted by protein precipitation with acetonitrile. The non-enantioselective method was conducted using a C18 column, and the mobile phase consisted of water for solvent A and acetonitrile for solvent B, both with 0.1% formic acid. For the chiral method, an analytical column Lux Cellulose-1 was used. Mobile phase A was composed of water with 0.025% of formic acid and 0.05% of diethylamine, and mobile phase B consisted of acetonitrile:2-propanol (95:5, v/v). No significant matrix effects were observed at the retention times of analytes and internal standard. The mean recovery was 89%, and the assays were linear in the concentration range of 1-50 and 5-30 ng/mL for the non-enantioselective and enantioselective methods, respectively. The intra- and inter-day precisions of both methods were less than 12.30%, and the accuracies were less than 12.13%. The validated methods were successfully applied to a pharmacokinetic study in which 20-mg CTP tablets were administered to healthy volunteers, and their plasma levels were monitored over time in a bioequivalence study. HIGHLIGHTS: Simple and rapid LC-MS/MS method for the quantification of citalopram and its enantiomers in human plasma. Both methods were demonstrated to be selective, reliable, and sensitive. Both methods have sufficient sensitivity to quantify the steady state through concentrations already reported for citalopram and escitalopram. Validated method presented in this study can be suitably applied to pharmacokinetic studies involving citalopram and escitalopram. Bland-Altman analysis suggested that non-enantioselective and enantioselective methods can be applied in pharmacokinetic studies.

Impact of repeated co-treatment with escitalopram and aripiprazole on the schizophrenia-like behaviors and BDNF mRNA expression in the adult Sprague-Dawley rats exposed to glutathione deficit during early postnatal development of the brain

BACKGROUND

Preclinical and clinical studies have indicated that impaired endogenous synthesis of glutathione during early postnatal development plays a significant role in the pathophysiology of schizophrenia. Moreover, some studies have suggested that antidepressants are able to increase the activity of atypical antipsychotics which may efficiently improve the treatment of negative and cognitive symptoms of schizophrenia.

METHODS

In the present study, we investigated the influence of repeated co-treatment with escitalopram and aripiprazole on the schizophrenia-like behavior and BDNF mRNA expression in adult rats exposed to glutathione deficit during early postnatal development. Male pups between the postnatal days p5-p16 were treated with the inhibitor of glutathione synthesis, BSO (L-buthionine-(S,R)-sulfoximine) and the dopamine uptake inhibitor, GBR 12,909 alone or in combination. Escitalopram and aripiprazole were given repeatedly for 21 days before the tests. On p90-92 rats were evaluated in the behavioral and biochemical tests.

RESULTS

BSO given alone and together with GBR 12,909 induced deficits in the studied behavioral tests and decreased the expression of BDNF mRNA. Repeated aripiprazole administration at a higher dose reversed these behavioral deficits. Co-treatment with aripiprazole and an ineffective dose of escitalopram also abolished the behavioral deficits in the studied tests.

CONCLUSION

The obtained data indicated that the inhibition of glutathione synthesis in early postnatal development induced long-term deficits corresponding to schizophrenia-like behavior and decreased the BDNF mRNA expression in adult rats, and these behavioral deficits were reversed by repeated treatment with a higher dose of aripiprazole and also by co-treatment with aripiprazole and ineffective dose of escitalopram.

Chronic social defeat stress impairs goal-directed behavior through dysregulation of ventral hippocampal activity in male mice

Chronic stress is a risk factor for a variety of psychiatric disorders, including depression. Although impairments to motivated behavior are a major symptom of clinical depression, little is known about the circuit mechanisms through which stress impairs motivation. Furthermore, research in animal models for depression has focused on impairments to hedonic aspects of motivation, whereas patient studies suggest that impairments to appetitive, goal-directed motivation contribute significantly to motivational impairments in depression. Here, we characterized goal-directed motivation in repeated social defeat stress (R-SDS), a well-established mouse model for depression in male mice. R-SDS impaired the ability to sustain and complete goal-directed behavior in a food-seeking operant lever-press task. Furthermore, stress-exposed mice segregated into susceptible and resilient subpopulations. Interestingly, susceptibility to stress-induced motivational impairments was unrelated to stress-induced social withdrawal, another prominent effect of R-SDS in mouse models. Based on evidence that ventral hippocampus (vHP) modulates sustainment of goal-directed behavior, we monitored vHP activity during the task using fiber photometry. Successful task completion was associated with suppression of ventral hippocampal neural activity. This suppression was diminished after R-SDS in stress-susceptible but not stress-resilient mice. The serotonin selective reuptake inhibitor (SSRI) escitalopram and ketamine both normalized vHP activity during the task and restored motivated behavior. Furthermore, optogenetic vHP inhibition was sufficient to restore motivated behavior after stress. These results identify vHP hyperactivity as a circuit mechanism of stress-induced impairments to goal-directed behavior and a putative biomarker that is sensitive to antidepressant treatments and that differentiates susceptible and resilient individuals.

Chronic Escitalopram Treatment Does Not Alter the Effects of Neonatal Stress on Hippocampal BDNF Levels, 5-HT1A Expression and Emotional Behaviour of Male and Female Adolescent Rats

Early life stress is considered a risk factor for the development of long-term psychiatric disorders. Maternal deprivation (MD) is a useful paradigm to understand the neurobiological underpinnings of early stress-induced changes in neurodevelopment trajectory. The goal of the present study was to examine the effects of a chronic treatment with escitalopram (ESC) on the hippocampal levels of BDNF and neuropeptide Y (NPY), expression of serotonin type 1A receptor (5-HT1A), plasma corticosterone levels and emotional behaviours in male and female adolescent rats submitted to MD at 9 days of life (group DEP9) and challenged with a brief and mild stress (saline injection (SAL)) at the end of MD. Whole litters were kept with mothers (CTL) or submitted to MD (DEP9). Within each group, pups were stress-challenged (CTL-SAL and DEP9-SAL) or not (CTL-NSAL and DEP9-NSAL). ESC or vehicle treatments began at weaning and lasted 24 days, when animals were sacrificed for determination of neurobiological variables or submitted to a battery of tests for evaluation of emotional behaviours. The results showed that BDNF levels were higher in SAL-challenged males and in DEP9-SAL females, whereas 5-HT1A receptor expression was reduced in DEP9 males and in SAL-challenged females. There were no changes in NPY or corticosterone levels. In the forced swim test, SAL-challenged males and DEP9 females displayed less immobility and ESC only increased social motivation in males. The results indicated that neonatal stress led to sex-dependent changes in neurobiology and behaviour and that chronic ESC treatment had minor effects on these parameters.

CRF-5-HT interactions in the dorsal raphe nucleus and motivation for stress-induced opioid reinstatement

RATIONALE

The serotonin (5-hydroxytryptamine, 5-HT) system plays an important role in stress-related psychiatric disorders and substance abuse. Our previous data show that stressors can inhibit 5-HT neuronal activity and release by stimulating the release of the stress neurohormone corticotropin-releasing factor (CRF) within the serotonergic dorsal raphe nucleus (DRN). The inhibitory effects of CRF on 5-HT DRN neurons are indirect, mediated by CRF-R1 receptors located on GABAergic afferents.

OBJECTIVES

We tested the hypothesis that DRN CRF-R1 receptors contribute to stress-induced reinstatement of morphine-conditioned place preference (CPP). We also examined the role of this circuitry in stress-induced negative affective state with 22-kHz distress ultrasonic vocalizations (USVs), which are naturally emitted by rats in response to environmental challenges such as pain, stress, and drug withdrawal.

METHODS

First, we tested if activation of CRF-R1 receptors in the DRN with the CRF-R1-preferring agonist ovine CRF (oCRF) would reinstate morphine CPP and then if blockade of CRF-R1 receptors in the DRN with the CRF-R1 antagonist NBI 35965 would attenuate swim stress-induced reinstatement of morphine CPP. Second, we tested if intra-DRN pretreatment with NBI 35965 would attenuate foot shock stress-induced 22-kHz USVs.

RESULTS

Intra-DRN injection of oCRF reinstated morphine CPP, while intra-DRN injection of NBI 35965 attenuated swim stress-induced reinstatement. Moreover, intra-DRN pretreatment with NBI 35965 significantly reduced 22-kHz distress calls induced by foot shock.

CONCLUSIONS

These data provide evidence that stress-induced negative affective state is mediated by DRN CRF-R1 receptors and may contribute to reinstatement of morphine CPP.

Triple reuptake inhibition of serotonin, norepinephrine, and dopamine increases the tonic activation of α2-adrenoceptors in the rat hippocampus and dopamine levels in the nucleus accumbens

Clinical studies have shown the therapeutic efficacy of an increase in dopamine (DA) transmission in treatment of major depressive disorder (MDD). In the present study, we investigated whether blockade of DA transporters in addition to serotonin (5-HT) and norepinephrine (NE) produced additional adaptations of monoaminergic systems. In vivo electrophysiological recordings were carried out in male anesthetized rats. Vehicle, the 5-HT reuptake inhibitor escitalopram, the NE/DA reuptake blocker nomifensine and their combination (triple reuptake inhibition; TRI) were delivered for 2 or 14 days. Firing activity of NE, 5-HT and DA neurons was assessed. Tonic activation of 5-HT_1A receptors and α₁- and α₂-adrenoceptors was determined in the hippocampus and extracellular DA levels in the nucleus accumbens (NAc). Unlike escitalopram, nomifensine and TRI administration increased the tonic activation of α₂-adrenoceptors in the hippocampus despite decreasing NE neuronal firing activity after 2 and 14 days of administration. The firing activity of 5-HT neurons was increased after prolonged nomifensine and TRI regimens, while addition of nomifensine to escitalopram prevented the early 2-day suppression of firing by 5-HT reuptake inhibition. The tonic activation of 5-HT_1A receptors was enhanced only with escitalopram. Whereas escitalopram and nomifensine decreased firing activity of DA neurons after a 2-day administration, their combination normalized it to baseline level after 14 days; this was accompanied by a robust increase in extracellular DA levels in the NAc. In summary, these results indicate that TRI increases NE and DA but not 5-HT transmission, suggesting a differential efficacy profile in MDD patients.

Enantioseparation and molecular modeling study of eight psychoactive drugs on a coated polysaccharide-based chiral stationary phase

The enantioseparation of eight psychoactive drugs has been firstly performed on a coated cellulose-based chiral stationary phase (Chiralcel OJ-H). To obtain optimum separation conditions, the influences of alcohol modifiers and basic/acidic additives have been studied. As a result, except for the partial separation of oxybutynin enantiomers, the other seven drug enantiomers, including mirtazapine, sulpiride, promethazine, citalopram, oxazepam, donepezil, and cyamemazine, have been completely separated. Additionally, for gaining a better insight into the chiral recognition mechanisms, molecular docking was carried out using the Autodock software. Herein, binding energy and conformations of the chiral stationary phase complexes were provided, and it was found that the distinction in enantiomeric conformation determined the number and strength of intermolecular interactions between analytes and chiral stationary phase which resulted in the difference in binding energies of two enantiomers, and ultimately led to the different migration. These modeling results were in accordance with the observed enantioseparation results in high performance liquid chromatography experiments. At last, chiral separation mechanisms have been discussed in detail, and it has been confirmed that hydrogen bond, π-π, hydrophobic interactions, and some special interactions synergistically contributed to the enantioseparation of psychoactive drugs.

The effects of acute serotonin challenge on executive planning in patients with obsessive-compulsive disorder (OCD), their first-degree relatives, and healthy controls

RATIONALE

Obsessive-compulsive disorder (OCD) is characterized by executive function impairment and by clinical responsivity to selective serotonin reuptake inhibitors (SSRIs). Executive planning deficits constitute a candidate endophenotype for OCD. It is not known whether this endophenotype is responsive to acute serotonin manipulation.

OBJECTIVE

The study aimed to investigate the effects of acute SSRI administration on executive function in patients with OCD, first-degree relatives of patients with OCD, and healthy controls.

METHODS

A randomized double-blind cross-over study assessed the effects of single-dose escitalopram (20 mg) and placebo on executive planning in 24 patients with OCD, 13 clinically unaffected first-degree relatives of patients with OCD, and 28 healthy controls. Performance on a Tower of London task measuring executive planning was assessed 4 h after oral administration of the pharmacological challenge/placebo and compared across and within groups using a mixed model analysis of variance.

RESULTS

On the outcome measure of interest, i.e., the mean number of choices to obtain the correct solution, there was a marginally significant effect of group (F(2, 59) = 3.1; p = 0.052), with patients (least square (LS) mean 1.43; standard error [SE] 0.06; 95% confidence interval (CI), 1.31-1.55) and their relatives (LS mean 1.46; SE 0.08; 95% CI, 1.30-1.62) performing worse than matched healthy controls (LS mean 1.26; SE 0.05; 95% CI, 1.15-1.37) on placebo. There was a trend towards a significant group × treatment interaction (F(2, 58) = 2.8, p = 0.069), with post hoc tests showing (i) patients (p = 0.009; LS mean difference 0.23; SE 0.08) and relatives (p = 0.03; LS mean difference 0.22; SE 0.10) were more impaired compared to controls and (ii) escitalopram was associated with improved executive planning in patients with OCD (p = 0.013; LS mean difference 0.1; SE 0.04), but not other groups (both p > 0.1; controls: LS mean difference - 0.03; SE 0.04; relatives: LS mean difference 0.02; SE 0.05).

CONCLUSION

Our findings are consistent with a view that there is impaired executive planning in OCD and that this constitutes a behavioural endophenotype. In patients with OCD, but not in relatives, acute SSRI administration ameliorated this deficit. Further investigation is needed to understand common and differential involvement of neurochemical systems in patients with OCD and their relatives.

Analysis of Density Changes of Selected Brain Receptors After a 14-Day Supply of Chromium(III) and Evaluation of Chromium(III) Affinity to Selected Receptors and Transporters

Chromium(III) is one of the most controversial biometals. Although, it is no longer on the list of minerals necessary for the proper functioning of the human body, and its pharmacological effect is still under discussion. One of the purposes of Cr(III) administration is to use it in patients with mood disorders and it is strictly related to its pharmacological, not dietary effect. This is because its high doses are necessary to obtain the results and additionally, no deficiencies in human population have been noted. In this study, the affinity of chromium(III) to selected receptors and transporters in the rat brain was evaluated, and the effect of the 14-day administration of this metal was assessed on the density of selected receptors. All analyses were performed in vitro using radioligand binding assays, and the results indicated lack of affinity to β₁ and α₁ receptors and serotonin transporter (SERT), furthermore very weak affinity to the 5-HT_1A receptor (30% inhibition at 10^-4 and 10^-5 M). Analysis of the α₁ and β₁ adrenergic receptor density indicated lack of any adaptive effects after 14 days of Cr(III) administration through intraperitoneal injections (doses 6 and 12 mg/kg). The antidepressant activity of chromium(III) indicated in clinical trials concerned patients with atypical, seasonal, or dystonic symptoms. This effect, as it seems based on the presented results, does not depend on direct affinity to serotonin receptors and transporter nor is the result of adaptive changes in the adrenoreceptor system.

SNRIs achieve faster antidepressant effects than SSRIs by elevating the concentrations of dopamine in the forebrain

Major depressive disorder (MDD) is a severe mental disorder with a high disability rate worldwide. Selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are the most common agents for antidepressant use. SSRIs and SNRIs are believed to achieve antidepressant effects through the activation of serotonergic or noradrenergic systems. However, whether the dopaminergic system is involved remains unclear. In our study, a genetically encoded dopamine sensor and in vivo fiber photometry recordings were used to measure the dopamine concentrations in the medial prefrontal cortex (mPFC) and nucleus accumbens (NAc) after acute intraperitoneal injection of SSRIs or SNRIs. Combined with the behavioral tests, we found that SNRIs increased dopamine concentrations in both the mPFC and the NAc and showed faster antidepressant effects than SSRIs. To verify the enhanced dopamine levels induce the faster antidepressant effects of SNRIs, we employed dopamine receptor antagonists to specifically block the dopaminergic function. The results showed that the faster antidepressant effects of SNRIs were weakened by the dopamine receptor antagonists. Altogether, our study reveals that SNRIs achieve faster antidepressant effects than SSRIs by elevating the dopamine concentrations in the mPFC and the NAc. Our work proposes further mechanisms for the first-line antidepressants, which provides more basis for clinical treatments. This article is part of the special issue on Stress, Addiction and Plasticity.

Serotonergic treatment normalizes midbrain dopaminergic neuron increase after periaqueductal gray stimulation

Electrical stimulation of the dorsolateral periaqueductal gray (dlPAG) in rats has been shown to elicit panic-like behaviour and can be a useful as an unconditioned stimulus for modelling anticipatory fear and agoraphobia in a contextual fear conditioning paradigm. In this study, we further analysed our previous data on the effects of escitalopram (a selective serotonin reuptake inhibitor, SSRI) and buspirone (a 5-HT1A receptor partial agonist) on dlPAG-induced anticipatory fear behaviour in a rat model using freezing as a measure. We then attempted to unravel some of the interactions with dopamine signalling using tyrosine hydroxylase (TH) immunohistochemistry to probe the effects on dopaminergic neurons. We showed that acute treatment of escitalopram, but not buspirone, was effective in reducing anticipatory freezing behaviour, while chronic administrations of both drugs were effective. We found that the dlPAG stimulation induced increase number of dopaminergic neurons in the ventral tegmental area (VTA) which was reversed in both chronic buspirone and escitalopram groups. We further found a strong positive correlation between the number of dopaminergic neurons and freezing in the VTA and showed positive correlations between dopaminergic neurons in the VTA and substantia nigra pars compacta (SNpc) in escitalopram and buspirone groups, respectively. Overall, we showed that chronic treatment with an SSRI and a 5-HT1A agonist reduced anticipatory freezing behaviour which seems to be associated, through correlative studies, with a reversal of dlPAG stimulation induced increase in number of dopaminergic neurons in the VTA and/or SNpc.

Effect of combined treatment with aripiprazole and antidepressants on the MK-801-induced deficits in recognition memory in novel recognition test and on the release of monoamines in the rat frontal cortex

According to preclinical and clinical studies, the antidepressant-induced increase in the activity of atypical antipsychotics may efficiently improve the treatment of negative and some cognitive symptoms of schizophrenia. In the present study, we aimed to evaluate the effects of the antidepressants escitalopram and mirtazapine and the atypical antipsychotic drug aripiprazole, administered separately or in combination, on the MK-801-induced deficits in the recognition memory test and on the extracellular levels of monoamines and their metabolites in the rat frontal cortex. Based on the results of the behavioral tests, co-treatment with an ineffective dose of aripiprazole (0.1 mg/kg) and escitalopram (2.5 and 5 mg/kg) or mirtazapine (5 mg/kg) abolished the deficits evoked by MK-801 in the novel object recognition test, and those effects were blocked by the 5-HT_1A receptor antagonist (WAY 100,635) or the dopamine D₁ receptor antagonist (SCH 23,390). Moreover, co-treatment with aripiprazole (0.3 mg/kg) and escitalopram (5 mg/kg) significantly increased the levels of noradrenaline and serotonin, decreased the level of its metabolite, and did not alter level of dopamine, but decreased the levels of its metabolites. In addition, co-treatment with aripiprazole (0.3 mg/kg) and mirtazapine (10 mg/kg) significantly increased the level of noradrenaline, did not change the levels of dopamine and serotonin, but increased the levels of their metabolites. Based on these results, the increase in the extracellular levels of noradrenaline or serotonin in the cortex induced by co-treatment with an antidepressant and aripiprazole may be very important for the pharmacotherapy of negative and some cognitive symptoms of schizophrenia.

Psychopharmacological Treatment of Obsessive-Compulsive Disorder (OCD)

Background:

Obsessive-compulsive disorder (OCD) is associated with affective and cognitive symptoms causing personal distress and reduced global functioning. These have considerable societal costs due to healthcare service utilization.

Objective:

Our aim was to assess the efficacy of pharmacological interventions in OCD and clinical guidelines, providing a comprehensive overview of this field.

Methods:

We searched the PubMed database for papers dealing with drug treatment of OCD, with a specific focus on clinical guidelines, treatments with antidepressants, antipsychotics, mood stabilizers, off-label medications, and pharmacogenomics.

Results:

Prolonged administration of selective serotonin reuptake inhibitors (SSRIs) is most effective. Better results can be obtained with a SSRI combined with cognitive behavioral therapy (CBT) or the similarly oriented exposure and response prevention (ERP). Refractory OCD could be treated with different strategies, including a switch to another SSRI or clomipramine, or augmentation with an atypical antipsychotic. The addition of medications other than antipsychotics or intravenous antidepressant administration needs further investigation, as the evidence is inconsistent. Pharmacogenomics and personalization of therapy could reduce treatment resistance.

Conclusions:

SSRI/clomipramine in combination with CBT/ERP is associated with the optimal response compared to each treatment alone or to other treatments. New strategies for refractory OCD are needed. The role of pharmacogenomics could become preponderant in the coming years.

Estimating dose-response for time to remission with instrumental variable adjustment: the obscuring effects of drug titration in Genome Based Therapeutic Drugs for Depression Trial (GENDEP): clinical trial data

Background

Threshold regression, in which time to remission is modelled as a stochastic drift towards a boundary, is an alternative to the proportional hazards survival model and has a clear conceptual mechanism for examining the effects of drug dose. However, for both threshold regression and proportional hazard models, when dose titration occurs during treatment, the estimated causal effect of dose can be biased by confounding. An instrumental variable analysis can be used to minimise such bias.

Method

Weekly antidepressant dose was measured in 380 men and women with major depression treated with escitalopram or nortriptyline for 12 weeks as part of the Genome Based Therapeutic Drugs for Depression (GENDEP) study. The averaged dose relative to maximum prescribing dose was calculated from the 12 trial weeks and tested for association with time to depression remission. We combined the instrumental variable approach, utilising randomised treatment as an instrument, with threshold regression and proportional hazard survival models.

Results

The threshold model was constructed with two linear predictors. In the naïve models, averaged daily dose was not associated with reduced time to remission. By contrast, the instrumental variable analyses showed a clear and significant relationship between increased dose and faster time to remission, threshold regression (velocity estimate: 0.878, 95% confidence interval [CI]: 0.152–1.603) and proportional hazards (log hazards ratio: 3.012, 95% CI: 0.086–5.938).

Conclusions

We demonstrate, using the GENDEP trial, the benefits of these analyses to estimate causal parameters rather than those that estimate associations. The results for the trial dataset show the link between antidepressant dose and time to depression remission. The threshold regression model more clearly distinguishes the factors associated with initial severity from those influencing treatment effect. Additionally, applying the instrumental variable estimator provides a more plausible causal estimate of drug dose on treatment effect. This validity of these results is subject to meeting the assumptions of instrumental variable analyses.

Trial registration

EudraCT, 2004–001723-38; ISRCTN, 03693000. Registered on 27 September 2007.

Co-treatment with antidepressants and aripiprazole reversed the MK-801-induced some negative symptoms of schizophrenia in rats

BACKGROUND

Schizophrenia is a chronic, most devastating psychiatric illness that impairs mental and social functioning. A few clinical reports have suggested that antidepressant drugs are able to augment the activity of atypical antipsychotic drugs, thus effectively improving treatment of some negative symptoms of schizophrenia.

METHODS

The aim of the present study was to investigate the effect of the antidepressant escitalopram or mirtazapine and aripiprazole (an atypical antipsychotic), given separately or jointly, on the deficits induced by MK-801(a noncompetitive N-methyl-d-aspartate receptor antagonist) in the social interaction test in male Sprague-Dawley rats. The social interaction was measured for 10 min, starting 4 h after MK-801 (0.1 mg/kg) administration. Antidepressants and aripiprazole were given 60 and 30 min before the test, respectively. WAY 100635 (a 5-HT1A antagonist) and SCH 23390 (a dopamine D1 antagonist) were give 20 min before the tests.

RESULTS

The present results showed that MK-801 (0.1 mg/kg)-induced deficits in the social interaction test. Aripiprazole (0.1 and 0.3 mg/kg) reversed those effects. Co-treatment with an ineffective dose of aripiprazole (0.03 mg/kg) and escitalopram (5 and 10 mg/kg) or mirtazapine (5 mg/kg) abolished the deficits evoked by MK-801, and those effects were especially blocked by a 5-HT1A receptor antagonist (WAY 100635) or partly by dopamine D1 receptor antagonist (SCH 23390).

CONCLUSIONS

The obtained results suggest that amelioration of the antipsychotic-like effect of aripiprazole by antidepressants in the MK-801-induced some negative symptoms of schizophrenia in rats may be associated with serotonin 5-HT1A and to a lesser degree with dopamine D1 receptors.

The Psychoactive Drug Escitalopram Affects Foraging Behavior in Zebrafish (Danio rerio)

Selective serotonin reuptake inhibitors (SSRIs) are psychoactive pharmaceuticals that have been detected intact in natural waters globally. Laboratory experiments have reported that several SSRIs inhibit fish foraging behavior, but data for the SSRI escitalopram are lacking. The objectives of the present study were to determine whether escitalopram affects feeding behavior in zebrafish and whether possible sex differences exist. We exposed female and male zebrafish (Danio rerio) to 0.00, 0.10, and 1.50 µg/L of escitalopram in flow-through tanks for a 3-wk exposure period. We used a video tracking system with high temporal and spatial resolution to collect data on zebrafish swimming patterns in test tanks containing a food source. The results show a more pronounced effect of escitalopram in males compared with females. At the assumed most environmentally relevant concentration (0.10 µg/L), male average feeding time/visit and maximum feeding duration were significantly reduced by 27 and 42%, respectively. In addition, male total feeding duration was also significantly reduced (by 73%) at the highest concentration (1.50 µg/L). In females, only the maximum feeding duration was significantly reduced (by 41%) in the 0.10 µg/L treatment group. Hence, we reject our initial hypothesis that female feeding behavior is more vulnerable to escitalopram. There was no effect of escitalopram on length or weight among the experimental groups. The present study demonstrates that escitalopram, like other SSRIs, can inhibit fish foraging behavior and therefore potentially disturb natural food chains. Finally, our study suggests that SSRIs can both be sex and behavior specific. Environ Toxicol Chem 2019;38:1902-1910. © 2019 SETAC.

Antidepressants affect gut microbiota and Ruminococcus flavefaciens is able to abolish their effects on depressive-like behavior

Accumulating evidence demonstrates that the gut microbiota affects brain function and behavior, including depressive behavior. Antidepressants are the main drugs used for treatment of depression. We hypothesized that antidepressant treatment could modify gut microbiota which can partially mediate their antidepressant effects. Mice were chronically treated with one of five antidepressants (fluoxetine, escitalopram, venlafaxine, duloxetine or desipramine), and gut microbiota was analyzed, using 16s rRNA gene sequencing. After characterization of differences in the microbiota, chosen bacterial species were supplemented to vehicle and antidepressant-treated mice, and depressive-like behavior was assessed to determine bacterial effects. RNA-seq analysis was performed to determine effects of bacterial treatment in the brain. Antidepressants reduced richness and increased beta diversity of gut bacteria, compared to controls. At the genus level, antidepressants reduced abundances of Ruminococcus, Adlercreutzia, and an unclassified Alphaproteobacteria. To examine implications of the dysregulated bacteria, we chose one of antidepressants (duloxetine) and investigated if its antidepressive effects can be attenuated by simultaneous treatment with Ruminococcus flavefaciens or Adlercreutzia equolifaciens. Supplementation with R. flavefaciens diminished duloxetine-induced decrease in depressive-like behavior, while A. equolifaciens had no such effect. R. flavefaciens treatment induced changes in cortical gene expression, up-regulating genes involved in mitochondrial oxidative phosphorylation, while down-regulating genes involved in neuronal plasticity. Our results demonstrate that various types of antidepressants alter gut microbiota composition, and further implicate a role for R. flavefaciens in alleviating depressive-like behavior. Moreover, R. flavefaciens affects gene networks in the brain, suggesting a mechanism for microbial regulation of antidepressant treatment efficiency.

Selective serotonin reuptake inhibition increases noise burst-induced unconditioned and context-conditioned freezing

OBJECTIVE

Whereas long-term administration of selective serotonin reuptake inhibitors (SSRIs) is effective for the treatment of anxiety disorders, acute administration of these drugs may exert a paradoxical anxiogenic effect. The aim of the present study was to explore the possible effect of an SSRI in situations of unconditioned or limited conditioned fear.

METHODS

Male Sprague Dawley rats were administered a single dose of an SSRI, escitalopram, before acquisition or expression of context conditioned fear, where noise bursts were used as the unconditioned stimulus. Freezing was assessed as a measure of unconditioned fear (=the acute response to noise bursts) or conditioned fear (=the response to the context), respectively.

RESULTS

Noise bursts elicited an acute increase in freezing but no robust conditioned response 7 days after exposure. Administration of escitalopram before testing exacerbated the freezing response during presentation of the unconditioned stimulus and also unmasked a conditioned response; in contrast, administration of escitalopram prior to acquisition did not influence the conditioned response.

CONCLUSION

The data suggest that freezing in rats exposed to a stimulus inducing relatively mild fear may be enhanced by acute pretreatment with an SSRI regardless of whether the freezing displayed by the animals is an acute unconditioned response to the stimulus in question or a conditioned response to the same stimulus.

Comparing escitaloipram with sertraline for obsessive and compulsive symptoms in patients with obsessive compulsive disorder: A comparative double blind clinical trial

BACKGROUND

Escitalopram has some unique features among selective serotonin reuptake inhibitors. The aim of this survey is to compare the efficacy of escitalopram with sertraline on obsessive and compulsive symptoms in patients with Obsessive Compulsive Disorder (OCD).

METHODS

In this 12-week double blind controlled randomized clinical trial, 57 patients with OCD were randomly allocated to receive escitalopram or sertraline. Yale Brown obsessive compulsive behavior scale (YBOCS) was used to assess the outcomes. Adverse effects were also recorded.

RESULTS

41 patients (20 in the escitalopram group and 21 in the sertraline group) completed the trial. In the escitalopram group 15 (70%) patients and in the sertraline group 16 (76.19%) patients showed more than 34% decrease in mean YBOCS score at the end of the trial (P=0.531). The two groups revealed significant decrease in YBOCS scores without significant difference (P=0.861) at week 12. No serious adverse effects were reported.

CONCLUSIONS

Our results demonstrated that escitalopram is as effective as sertraline in treatment of obsessions and compulsions in patients with OCD. However, it needs to be noted that our study is preliminary and larger double blind controlled studies are needed to confirm the results.

Searching for neural and behavioral parameters that predict anti-aggressive effects of chronic SSRI treatment in rats

RATIONALE

Only a subset of impulsive aggressive patients benefits from selective serotonin reuptake inhibitor (SSRI) treatment, confirming contradictory results about the association between serotonin (5-hydroxytryptamine, 5-HT) and aggression. This shows the need to define behavioral characteristics within this subgroup to move towards individualized pharmacological treatment of impulsive aggression.

METHODS

Here we submitted an outbred strain of Long Evans rats to a crossover design treatment regimen with the SSRI citalopram, to test its anti-aggressive effect. Behavioral characteristics were baseline aggression, anxiety parameters as measured in the elevated plus maze and open field and cue responsivity as indicated by sign vs. goal tracking behavior. 5-HT_1A receptor densities as measured by ex vivo [¹⁸F]MPPF binding were determined in the dorsal raphe nucleus, dentate gyrus, orbitofrontal cortex, infralimbic cortex and prelimbic cortex, because of the receptors' involvement in the therapeutic delay of SSRIs and aggression.

RESULTS

We found statistically significant increased variance in aggressive behavior after citalopram treatment. However, none of the selected parameters predicted the citalopram treatment effect.

CONCLUSION

Since aggression after citalopram treatment decreased in a subgroup of animals and increased in the other, future research should focus on other possible predictors to support treatment strategies in aggressive patients.

Treatment with escitalopram modulates cardiovascular function in rats

Considering depression is three times more common in cardiac patients compared to the normal population and selective serotonin reuptake inhibitors (SSRI) as drug of choice for treating patients with cardiovascular disease and depression, our work aims to evaluate the cardiovascular effects of treatment for 21 days with escitalopram (5 mg/kg/day, ip) in rats. The treatment caused an increase in mean arterial pressure concomitant with a decrease in heart rate. Concerning heart rate variability, there was a significant reduction in the sympathetic component and an elevation of the parasympathetic component, indicating that escitalopram caused an autonomic imbalance with parasympathetic predominance. In addition, we observed a decrease in both low and very low frequency power in blood pressure variability. The cardiac autonomic blockade indicated an increase in parasympathetic modulation to the heart with escitalopram chronic treatment. However, no change was observed on baroreflex activity. On the other hand, there was a decrease in pressure response during acute restraint stress with no changes in the tachycardia response. These findings showed that despite the escitalopram be a relatively safe drug it can cause tonic effects on cardiovascular function as well as during aversive situations.

Vortioxetine Treatment Reverses Subchronic PCP Treatment-Induced Cognitive Impairments: A Potential Role for Serotonin Receptor-Mediated Regulation of GABA Neurotransmission

Major depressive disorder (MDD) is associated with cognitive impairments that may contribute to poor functional outcomes. Clinical data suggests that the multimodal antidepressant vortioxetine attenuates some cognitive impairments in MDD patients, but the mechanistic basis for these improvements is unclear. One theory suggests that vortioxetine improves cognition by suppressing γ-amino butyric acid (GABA)ergic neurotransmission, thereby increasing glutamatergic activation. Vortioxetine’s effects on cognition, GABA and glutamate neurotransmission have been supported in separate experiments, but no empirical work has directly connected vortioxetine’s cognitive effects to those on GABA and glutamate neurotransmission. In this paper, we attempt to bridge this gap by evaluating vortioxetine’s effects in the subchronic PCP (subPCP) model, which induces impaired cognitive function and altered GABA and glutamate neurotransmission. We demonstrate that acute or subchronic vortioxetine treatment attenuated subPCP-induced deficits in attentional set shifting (AST) performance, and that the selective 5-HT₃ receptor antagonist ondansetron or the 5-HT reuptake inhibitor escitalopram could mimic this effect. Furthermore, acute vortioxetine treatment reversed subPCP-induced object recognition (OR) deficits in rats, while subchronic vortioxetine reversed subPCP-induced Object Recognition and object placement impairments in mice. Finally, subPCP treatment reduced GABA_B receptor expression in a manner that was insensitive to vortioxetine treatment, and subchronic vortioxetine treatment alone, but not in combination with subPCP, significantly increased GABA’s affinity for the GABA_A receptor. These data suggest that vortioxetine reverses cognitive impairments in a model associated with altered GABA and glutamate neurotransmission, further supporting the hypothesis that vortioxetine’s GABAergic and glutamatergic effects are relevant for cognitive function.

Developmental exposure to the SSRI citalopram causes long-lasting behavioural effects in the three-spined stickleback (Gasterosteus aculeatus)

Selective Serotonin re-uptake inhibitors (SSRIs) are a class of psychotropic drugs used to treat depression in both adolescents and pregnant or breast-feeding mothers as well as in the general population. Recent research on rodents points to long-lasting behavioural effects of pre- and perinatal exposure to SSRIs which last into adulthood. In fish however, studies on effects of developmental exposure to SSRIs appears to be non-existent. In order to study effects of developmental SSRI exposure in fish, three-spine sticklebacks were exposed to 1.5 µg/l of the SSRI citalopram in the ambient water for 30 days, starting two days post-fertilisation. After approximately 100 days of remediation in clean water the fish were put through an extensive battery of behavioural tests. Feeding behaviour was tested as the number of bites against a piece of food and found to be increased in the exposed fish. Aggression levels were measured as the number of bites against a mirror image during 10 min and was also found to be significantly increased in the exposed fish. Novel tank behaviour and locomotor activity was tested in an aquarium that had a horizontal line drawn half-way between the bottom and the surface. Neither the latency to the first transition to the upper half, nor the number of transitions or the total time spent in the upper half was affected by treatment. Locomotor activity was significantly reduced in the exposed fish. The light/dark preference was tested in an aquarium where the bottom and walls were black on one side and white on the other. The number of transitions to the white side was significantly reduced in the exposed fish but there was no effect on the latency to the first transition or the total time spent in the white half. The results in the current study indicate that developmental SSRI exposure causes long-lasting behavioural effects in fish and contribute to the existing knowledge about SSRIs as environmental pollutants.

Escitalopram and NHT normalized stress-induced anhedonia and molecular neuroadaptations in a mouse model of depression

Anhedonia is defined as a diminished ability to obtain pleasure from otherwise positive stimuli. Anxiety and mood disorders have been previously associated with dysregulation of the reward system, with anhedonia as a core element of major depressive disorder (MDD). The aim of the present study was to investigate whether stress-induced anhedonia could be prevented by treatments with escitalopram or novel herbal treatment (NHT) in an animal model of depression. Unpredictable chronic mild stress (UCMS) was administered for 4 weeks on ICR outbred mice. Following stress exposure, animals were randomly assigned to pharmacological treatment groups (i.e., saline, escitalopram or NHT). Treatments were delivered for 3 weeks. Hedonic tone was examined via ethanol and sucrose preferences. Biological indices pertinent to MDD and anhedonia were assessed: namely, hippocampal brain-derived neurotrophic factor (BDNF) and striatal dopamine receptor D2 (Drd2) mRNA expression levels. The results indicate that the UCMS-induced reductions in ethanol or sucrose preferences were normalized by escitalopram or NHT. This implies a resemblance between sucrose and ethanol in their hedonic-eliciting property. On a neurobiological aspect, UCMS-induced reduction in hippocampal BDNF levels was normalized by escitalopram or NHT, while UCMS-induced reduction in striatal Drd2 mRNA levels was normalized solely by NHT. The results accentuate the association of stress and anhedonia, and pinpoint a distinct effect for NHT on striatal Drd2 expression.

Whole-body hyperthermia and a subthreshold dose of citalopram act synergistically to induce antidepressant-like behavioral responses in adolescent rats

BACKGROUND

Open and randomized, double blind, placebo-controlled clinical trials have demonstrated clinical efficacy of infrared whole-body hyperthermia in treatment of major depressive disorder (MDD). Demonstration of antidepressant-like behavioral effects of whole-body hyperthermia in preclinical rodent models would provide further support for the clinical use of infrared whole-body hyperthermia for the treatment of MDD, and would provide additional opportunities to explore underlying mechanisms.

METHODS

Adolescent male Wistar rats were habituated daily for 7days to an incubator (23°C, 15min), then exposed, 24h later, to an 85-min period of whole-body hyperthermia (37°C) or control conditions (23°C), with or without pretreatment with a subthreshold dose of the selective serotonin reuptake inhibitor, citalopram (5mg/kg, s.c., 23h, 5h, and 1h before behavioral testing in a 5-min forced swim test). Rectal temperature was monitored daily and immediately before and after the forced swim test to determine the relationship between body temperature and antidepressant-like behavioral responses.

RESULTS

Whole-body hyperthermia and citalopram independently increased body temperature and acted synergistically to induce antidepressant-like behavioral responses, as measured by increased swimming and decreased immobility in the absence of any effect on climbing behaviors in the forced swim test, consistent with a serotonergic mechanism of action.

CONCLUSIONS

Preclinical data support use of infrared whole-body hyperthermia in the treatment of MDD.

Sigma-1 receptor ligands inhibit catecholamine secretion from adrenal chromaffin cells due to block of nicotinic acetylcholine receptors

Adrenal chromaffin cells (ACCs) are the neuroendocrine arm of the sympathetic nervous system and key mediators of the physiological stress response. Acetylcholine (ACh) released from preganglionic splanchnic nerves activates nicotinic acetylcholine receptors (nAChRs) on chromaffin cells causing membrane depolarization, opening voltage-gated Ca2+ channels (VGCC), and exocytosis of catecholamines and neuropeptides. The serotonin transporter is expressed in ACCs and interacts with 5-HT1A receptors to control secretion. In addition to blocking the serotonin transporter, some selective serotonin reuptake inhibitors (SSRIs) are also agonists at sigma-1 receptors which function as intracellular chaperone proteins and can translocate to the plasma membrane to modulate ion channels. Therefore, we investigated whether SSRIs and other sigma-1 receptor ligands can modulate stimulus-secretion coupling in ACCs. Escitalopram and fluvoxamine (100 nM to 1 μM) reversibly inhibited nAChR currents. The sigma-1 receptor antagonists NE-100 and BD-1047 also blocked nAChR currents (≈ 50% block at 100 nM) as did PRE-084, a sigma-1 receptor agonist. Block of nAChR currents by fluvoxamine and NE-100 was not additive suggesting a common site of action. VGCC currents were unaffected by the drugs. Neither the increase in cytosolic [Ca2+ ] nor the resulting catecholamine secretion evoked by direct membrane depolarization to bypass nAChRs was altered by fluvoxamine or NE-100. However, both Ca2+ entry and catecholamine secretion evoked by the cholinergic agonist carbachol were significantly reduced by fluvoxamine or NE-100. Together, our data suggest that sigma-1 receptors do not acutely regulate catecholamine secretion. Rather, SSRIs and other sigma-1 receptor ligands inhibit secretion evoked by cholinergic stimulation because of direct block of Ca2+ entry via nAChRs.

Polymorphisms of 5-HTT LPR and GNβ3 825C>T and Response to Antidepressant Treatment in Functional Dyspepsia: A Study from The Functional Dyspepsia Treatment Trial

OBJECTIVES

The Functional Dyspepsia Treatment Trial reported that amitriptyline (AMI) was associated with adequate relief of functional dyspepsia (FD) symptoms, but the pharmacogenetics of antidepressant response in FD are not known. GNβ3 825C>T CC genotype has been previously linked to FD and TT genotype to antidepressant response in depression. The ss genotype of the 5-HTT LPR variant of the serotonin transporter gene (SLC6A4) has been linked to selective serotonin reuptake inhibitor (SSRI) response. We aimed to examine whether GNβ3 825C>T and 5-HTT LPR polymorphisms result in differential treatment effects in FD patients receiving antidepressant therapy.

METHODS

Participants were randomized to receive placebo, 50 mg AMI, or 10 mg escitalopram (ESC). The primary end point was adequate relief for ≥5 weeks of the last 10 weeks. Genotyping of GNβ3 825C>T and 5-HTT LPR was performed utilizing PCR-based methods.

RESULTS

GNβ3 825C>T and 5-HTT LPR genotype data were available for 256 (88%) and 246 (84%) patients, respectively. Both polymorphisms were in Hardy-Weinberg equilibrium. In tests for differential treatment, neither 5-HTT LPR nor GNβ3 825C>T genotype influenced response to therapy (P=0.89 and P=0.54, respectively). Although there was a tendency for a more favorable response to ESC in the SS/LS genotype compared to the LL genotype groups (40% vs. 31% reporting adequate relief of FD symptoms) among those in the ESC treatment arm, this was not significant (P=0.43).

CONCLUSIONS

GNβ3 825C>T and 5-HTT LPR genetic variants do not alter treatment response to tricyclic and SSRI antidepressants in FD.

Highly polygenic architecture of antidepressant treatment response: Comparative analysis of SSRI and NRI treatment in an animal model of depression

Response to antidepressant (AD) treatment may be a more polygenic trait than previously hypothesized, with many genetic variants interacting in yet unclear ways. In this study we used methods that can automatically learn to detect patterns of statistical regularity from a sparsely distributed signal across hippocampal transcriptome measurements in a large-scale animal pharmacogenomic study to uncover genomic variations associated with AD. The study used four inbred mouse strains of both sexes, two drug treatments, and a control group (escitalopram, nortriptyline, and saline). Multi-class and binary classification using Machine Learning (ML) and regularization algorithms using iterative and univariate feature selection methods, including InfoGain, mRMR, ANOVA, and Chi Square, were used to uncover genomic markers associated with AD response. Relevant genes were selected based on Jaccard distance and carried forward for gene-network analysis. Linear association methods uncovered only one gene associated with drug treatment response. The implementation of ML algorithms, together with feature reduction methods, revealed a set of 204 genes associated with SSRI and 241 genes associated with NRI response. Although only 10% of genes overlapped across the two drugs, network analysis shows that both drugs modulated the CREB pathway, through different molecular mechanisms. Through careful implementation and optimisations, the algorithms detected a weak signal used to predict whether an animal was treated with nortriptyline (77%) or escitalopram (67%) on an independent testing set. The results from this study indicate that the molecular signature of AD treatment may include a much broader range of genomic markers than previously hypothesized, suggesting that response to medication may be as complex as the pathology. The search for biomarkers of antidepressant treatment response could therefore consider a higher number of genetic markers and their interactions. Through predominately different molecular targets and mechanisms of action, the two drugs modulate the same Creb1 pathway which plays a key role in neurotrophic responses and in inflammatory processes. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.

Potential functional and pathological side effects related to off-target pharmacological activity

Most pharmaceutical companies test their discovery-stage proprietary molecules in a battery of in vitro pharmacology assays to try to determine off-target interactions. During all phases of drug discovery and development, various questions arise regarding potential side effects associated with such off-target pharmacological activity. Here we present a scientific literature curation effort undertaken to determine and summarize the most likely functional and pathological outcomes associated with interactions at 70 receptors, enzymes, ion channels and transporters with established links to adverse effects. To that end, the scientific literature was reviewed using an on-line database, and the most commonly reported effects were summarized in tabular format. The resultant table should serve as a practical guide for research scientists and clinical investigators for the prediction and interpretation of adverse side effects associated with molecules interacting with components of this screening battery.