vortioxetine and Disease-Models--Animal

Depression, one of the most significant mental disorders, is still poorly understood in terms of its pathogenetic mechanisms despite its well-recognized association with stress.. The current study's goal was to ascertain how the novel antidepressant drug vortioxetine (VOR) affected the BDNF (brain-derived neurotrophic factor), S100, amyloid β (Aβ), CREB (cAMP response element-binding protein), and NR2B, as well as its impact on depression-like behaviors, and tissue damage in an experimental rodent model of depression caused by chronic unpredictable stress.. We employed twenty-eight Wistar albino male rats, and we randomly divided them into four groups, each consisting of 7 rats: control, CUMS (chronic unpredictable mild stress), CUMS+vortioxetine (CUMS+VOR), and CUMS+fluoxetine (CUMS+FLU). Sucrose preference and forced swimming tests (SPT and FST, respectively), PCR, ELISA, and histopathological and immunohistochemical evaluation were made on brains.. The behaviors of reduced immobility in the FST and increased sucrose preference were observed in the CUMS group and they improved in the groups treated with VOR and FLU. Compared with the control group, the group exposed to CUMS showed increased Aβ and decreased BDNF, CREB, and S-100 expressions, as well as neuronal degeneration (p<0.001). VOR and FLU treatment ameliorate the findings.. This study demonstrated significant ameliorative effects of VOR in an experimental model of chronic unpredictable depression to reduce brain tissue damage and depression-like behaviors in rats. Effects of CUMS on the brain and possible effects of VOR.

Topics: Amyloid beta-Peptides; Animals; Brain-Derived Neurotrophic Factor; Depression; Disease Models, Animal; Glutamates; Hippocampus; Humans; Rats; Rats, Wistar; S100 Calcium Binding Protein beta Subunit; Stress, Psychological; Sucrose; Vortioxetine

Depression is a very prevalent psychiatric disorder which threats nearly one in six of the population in this world. To date, the pathogenesis of depression remains elusive and is thought to depend on multiple factors in which chronic stress is critical. Currently, it has been demonstrated that besides monoaminergic dysfunction, depression is accompanied by several other important pathological phenomena such as impaired neurogenesis and decreased brain-derived neurotrophic factor (BDNF)-cAMP response element binding protein (CREB) signaling cascade in the hippocampus. F3/Contactin is a cell-adhesion molecule which has been reported to correlate with hippocampal neurogenesis and BDNF-CREB signaling. Here we assumed that F3/Contactin may be implicated in depression, and various methods including western blotting, immunofluorescence, virus-mediated gene transfer and chronic stress models of depression were adopted together. It was found that both chronic restraint stress (CRS) and chronic social defeat stress (CSDS) significantly decreased the expression of F3/Contactin in the hippocampus. Adeno-associated virus (AAV)-mediated over-expression of hippocampal F3/Contactin notably prevented the CRS-induced and CSDS-induced depressive-like behaviors in mice. Moreover, hippocampal F3/Contactin over-expression also fully reversed the CRS-induced and CSDS-induced dysfunction in the hippocampal BDNF-CREB signaling and neurogenesis of mice. Furthermore, administration of vortioxetine, a multimodal-acting antidepressant, fully ameliorated the inhibitory actions of both CRS and CSDS on the hippocampal F3/Contactin expression. In contrast, AAV-mediated knockdown of hippocampal F3/Contactin significantly abolished the protecting effects of vortioxetine against CRS and CSDS. Collectively, hippocampal F3/Contactin is implicated in depression and could be a novel antidepressant target.

Topics: Animals; Antidepressive Agents; Brain-Derived Neurotrophic Factor; Contactins; Cyclic AMP Response Element-Binding Protein; Depression; Disease Models, Animal; Hippocampus; Humans; Mice; Mice, Inbred C57BL; Stress, Psychological; Vortioxetine

This study aimed to examine the effects of vortioxetine, a novel antidepressant, on epileptiform activity in pentylenetetrazole (PTZ)-induced kindling model in rats. For this purpose, 20 male Wistar Albino rats were used, and epileptiform activity was induced by injection of PTZ (35 mg/kg, i.p., three times a week). In the vortioxetine groups, vortioxetine (5 mg/kg and 10 mg/kg) was administered before the kindling process. During the kindling process, the Fisher and Kittner seizure scales were used to score seizure severity. After kindling, novel object recognition (NOR) tests were performed to evaluate the cognitive performance of rats. Electrodes were implanted into the fully kindled animals for ECoG recordings. In the PTZ group, the number of total spikes was 1367±136 spikes/20 minutes. First myoclonic jerks decreased while seizure severity and total spike count increased in the PTZ group. On the other hand, the total spike number and seizure severity significantly decreased and first myoclonic jerks increased in the vortioxetine groups compared to the PTZ group. Based on the NOR test, vortioxetine administration markedly raised the discrimination index compared to the PTZ group. Electrophysiological and behavioural data from the present study suggest that vortioxetine, a novel drug, plays a critical role in controlling PTZ-induced epileptiform activity in rats. Vortioxetine may therefore be a valuable candidate to prevent seizure activity and treat cognitive deficits associated with epilepsy.

Topics: Animals; Cognition; Disease Models, Animal; Male; Myoclonus; Pentylenetetrazole; Rats; Rats, Wistar; Seizures; Vortioxetine

Depression is the major psychiatric disorder in patients with epilepsy. Vortioxetine is a novel antidepressant drug for the treatment of major depressive disorders. In the present study, effects of vortioxetine were evaluated in different experimental epilepsy models of rats.. Fifty-six adult male Wistar rats and 28 WAG/Rij rats were divided into 12 groups of 7 rats each. Experiments were conducted with penicillin (500 IU, i.c.) and pentylenetetrazole models (50 mg/kg, intraperitoneally (i.p.)) in Wistar rats and genetic absence epileptic WAG/Rij rats. The vortioxetine (1, 5, or 10 mg/kg, i.p.) was evaluated in these three models. All groups were compared with their control groups.. In the penicillin-induced seizure model, 1, 5, or 10 mg/kg vortioxetine administration significantly decreased mean spike frequency. In the pentylenetetrazole-induced seizure model, 1, 5, or 10 mg/kg vortioxetine demonstrated a significant dose-dependent decrease in mean spike frequency, an increase in the latency to minor and major seizures, and a decrease in total duration of major seizure and convulsion stage. In genetic absence epileptic WAG/Rij rats, 1 mg/kg vortioxetine caused no significant alteration in the number and duration of SWDs compared to the controls, while 5 and 10 mg/kg doses of vortioxetine increased the number and duration of SWDs. Amplitude of the epileptiform activity did not change in any of the experimental epilepsy models.. The results of this study suggested that vortioxetine has anticonvulsant activity in penicillin- and pentylenetetrazole-induced seizure models. However, it exhibited proconvulsant activity in the absence epileptic WAG/Rij rats.

Topics: Animals; Depressive Disorder, Major; Disease Models, Animal; Electroencephalography; Epilepsy, Absence; Humans; Male; Penicillins; Pentylenetetrazole; Rats; Rats, Wistar; Seizures; Vortioxetine

Post-traumatic stress disorder (PTSD) can be observed after a traumatic event. The effect of an antidepressant vortioxetine (Vrx) against PTSD is unknown. The aim of this study was to investigate the possible protective effect of Vrx in the predator scent-induced PTSD rat model. The rats were exposed to dirty cat litter for 10 min and the protocol was repeated 1 week later with clean cat litter as a trauma reminder. The rats received Vrx (10 mg/kg/p.o.) or saline (1 ml/kg/p.o.) during 7 days between two exposure sessions. Novel object recognition test, hole board test, and elevated plus maze were performed. The b-cell lymphoma (bcl-2)/bcl-2-associated X protein (bax) ratio, brain-derived neurotrophic factor (BDNF), caspase-3 and -9 expressions were detected using Western blotting in the amygdaloid complex, hippocampus, and frontal cortex. Our results indicate that increased freezing time and anxiety index in the stress-induced group is decreased with Vrx application. Vrx treatment improved deteriorated recognition memory in the stress-induced group. Decreased bcl-2/bax ratio and BDNF level and increased caspase-3 and -9 expressions in the stress group, improved with Vrx in the amygdala, and hippocampus. Decreased bcl-2/bax ratio and increased casp-3 and -9 expressions in the stress group are ameliorated with Vrx in frontal cortex. The level of BDNF was increased with Vrx in the frontal cortex. Increased damage scores in the amygdaloid complex, hippocampal CA3, and frontal cortex in the stress group ameliorated with Vrx treatment. Our results show that if vortioxetine is administered immediately after trauma, it reduces anxiety, cognitive and neuronal impairment and may be protective against the development of PTSD.

Topics: Animals; Apoptosis; Behavior, Animal; Brain; Brain-Derived Neurotrophic Factor; Cats; Cognitive Dysfunction; Disease Models, Animal; Male; Memory; Neuronal Plasticity; Neuroprotective Agents; Odorants; Rats, Wistar; Stress Disorders, Post-Traumatic; Stress, Psychological; Vortioxetine

Depression is a highly prevalent social disease. Despite significant medical progress, therapeutic solutions for optimising treatment of this disease are still being sought. The aim of this study was to assess, using the forced swimming test, locomotor activity test and two compartment exploratory test, for a reduction in immobility time (a measure of anti-depressant efficacy), locomotor activity and anxiolytic effectiveness after single, repeated, and combined administration of vortioxetine (2.5 mg/kg - a multimodal SMS), dapoxetine (3.0 mg/kg - an SSRI used in premature ejaculation disorders) and fluoxetine (5.0 mg/kg - an SSRI) in non-stressed and prenatally stressed rats. It was found that vortioxetine, fluoxetine and dapoxetine reduced immobility time and rat locomotor activity which suggests anti-depressant efficacy of these drugs both in monotherapy and in combined administration. The results also confirmed an anxiolytic effect of the study drugs in mono and combined therapy. Analysis of the pathomechanism of depression and the mechanisms of action of the individual drugs tested resulted in a prediction that combined administration of these drugs may be effective in the treatment of depressive disorders, although possible interactions between the drugs used must be assessed for. Considering the fact that dapoxetine is not currently used in depression treatment and vortioxetine is a relatively new drug, further research in this direction is vital, including within animal models.

Topics: Animals; Antidepressive Agents; Benzylamines; Disease Models, Animal; Drug Administration Schedule; Drug Therapy, Combination; Exploratory Behavior; Female; Fluoxetine; Immobility Response, Tonic; Locomotion; Male; Naphthalenes; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Wistar; Statistics, Nonparametric; Stress, Psychological; Swimming; Time Factors; Treatment Outcome; Vortioxetine

The aim of this study was to investigate the antidepressant activity of vortioxetine in a tryptophan (TRP) depletion female rat model of depression and compare it to that of paroxetine using doses that fully occupy the serotonin transporter (SERT). We evaluated the effects of vortioxetine on potential biomarkers associated with TRP depletion including serum aldosterone, corticosterone and IL-6 levels together with indirect indicators of glutamate neurotransmission. Female Sprague-Dawley rats were randomized to control, low TRP, low TRP/paroxetine or low TRP/vortioxetine groups. Vortioxetine and paroxetine were administered via diet (10mg/kg/day) and drinking water (10mg/kg/day) respectively for 14days. Vortioxetine but not paroxetine reversed TRP depletion-induced depressive-like behavior. Vortioxetine reduced TRP depletion-induced increases of serum corticosterone, aldosterone, IL-6 and N-methyl-d-aspartate and α7-nicotinic acetylcholine receptor expression in the amygdala and hippocampus, respectively. Paroxetine demonstrated little effect except a reduction of aldosterone. Vortioxetine but not paroxetine reversed TRP depletion-induced reductions of serum and brain kynurenic acid. In conclusion, vortioxetine, but not paroxetine, enabled reversals of TRP depletion-induced changes of depression-like behavior and markers of glutamatergic activity. These observations support the hypothesis that vortioxetine's antidepressant activity may involve mechanisms beyond SERT inhibition.

Topics: Administration, Oral; Animals; Biomarkers; Depressive Disorder; Disease Models, Animal; Female; Glutamic Acid; Paroxetine; Random Allocation; Rats, Sprague-Dawley; Selective Serotonin Reuptake Inhibitors; Vortioxetine

Vortioxetine is a novel antidepressant capable of improving depressive and cognitive symptoms associated with major depressive disorder (MDD). This study established whether treatment with vortioxetine, fluoxetine or vehicle alters the modulation of brain-derived neurotrophic factor (BDNF) under the 21-day chronic unpredictable mild stress (CUMS) condition in 54 Sprague-Dawley rats. Vortioxetine mitigated the reduction in rearing behavior by CUMS in the OFT on day 7 and 21, as well as sucrose preference on day 21. Histological examination by H&E staining showed that most hippocampal neurons in the CUMS + FLU and CUMS + VOR groups were intact, although some of them demonstrated karyopyknosis. The mean optical density value of hippocampal BDNF was significantly higher in the CUMS + VOR group than the CUMS and CUMS + FLU groups. There was a trend towards a higher number of hippocampal BDNF-positive cells in the CUMS + VOR group, although it did not reach statistical significance. In conclusion, vortioxetine, but not fluoxetine, increased hippocampal BDNF levels in rats subject to CUMS.

Topics: Anhedonia; Animals; Antidepressive Agents; Brain-Derived Neurotrophic Factor; Depressive Disorder, Major; Disease Models, Animal; Fluoxetine; Hippocampus; Male; Neurons; Random Allocation; Rats, Sprague-Dawley; Stress, Psychological; Vortioxetine

We studied the effects of the multi-modal antidepressant, vortioxetine and the SSRI, paroxetine on pineal melatonin and monoamine synthesis in a sub-chronic tryptophan (TRP) depletion model of depression based on a low TRP diet. Female Sprague-Dawley rats were randomised to groups a) control, b) low TRP diet, c) low TRP diet+paroxetine and d) low TRP diet+vortioxetine. Vortioxetine was administered via the diet (0.76mg/kg of food weight) and paroxetine via drinking water (10mg/kg/day) for 14days. Both drugs resulted in SERT occupancies >90%. Vortioxetine significantly reversed TRP depletion-induced reductions of pineal melatonin and serotonin (5-HT) and significantly increased pineal noradrenaline NA. Paroxetine did none of these things. Other studies suggest pineal melatonin synthesis may involve N-methyl-d-aspartate (NMDA) receptors and glutamatergic modulation. Here observed changes may be mediated via vortioxetine's strong 5-HT reuptake blocking action together with possible additional effects on glutamate neurotransmission in the pineal via NMDA receptor-modulation and possibly with added impetus from increased NA output.

Topics: Administration, Oral; Animals; Antidepressive Agents, Second-Generation; Depressive Disorder; Disease Models, Animal; Female; Glutamic Acid; Melatonin; Norepinephrine; Paroxetine; Pineal Gland; Piperazines; Random Allocation; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; RNA-Binding Proteins; Selective Serotonin Reuptake Inhibitors; Serotonin; Sulfides; Tryptophan; Vortioxetine

Stress is a risk factor for depression and anxiety disorders, disrupting neuronal processes leading to exaggerated fear and compromised coping behaviors. Current antidepressants are only partially effective. Vortioxetine, a novel multimodal antidepressant, is a serotonin transporter inhibitor; 5-HT3, 5-HT7, and 5-HT1D receptor antagonist; 5-HT1B partial agonist; and 5-HT1A agonist. We have shown that chronic dietary vortioxetine administration reversed stress-induced deficits in cognitive flexibility. In the present studies, we investigated the generality of vortioxetine's effects on other stress-related behavioral changes after different types of chronic stress.. In experiment 1, rats were fear-conditioned by pairing a tone with footshock, then exposed to chronic plus acute prolonged stress. In experiment 2, rats were exposed to chronic unpredictable stress. In both experiments, beginning on day 4 of chronic stress, vortioxetine was given in the diet (24 mg/kg/d). In experiment 1, effects of vortioxetine were tested on stress-induced changes in retention and extinction of cue-conditioned fear, and in experiment 2, on coping behavior on the shock probe defensive burying test after chronic stress.. Chronic stress exaggerated the expression of conditioned fear memory. Vortioxetine restored fear memory to control levels and rendered extinction in stressed rats comparable with that in controls. In experiment 2, chronic unpredictable stress caused a shift from active to passive coping behavior, and vortioxetine restored active coping.. Vortioxetine reduced exaggerated expression of conditioned fear and restored adaptive coping behavior following 2 different types of chronic stress, adding to the evidence of its therapeutic potential in the management of depression and anxiety disorders.

Topics: Adaptation, Psychological; Analysis of Variance; Animals; Anti-Anxiety Agents; Conditioning, Psychological; Cues; Disease Models, Animal; Electroshock; Extinction, Psychological; Fear; Immobility Response, Tonic; Male; Memory Disorders; Piperazines; Rats; Rats, Sprague-Dawley; Stress, Psychological; Sulfides; Time Factors; Vortioxetine

To investigate the effects of vortioxetine on cAMP/CREB/BDNF signal pathway.. Forty Kunming mice were randomized into control group and chronic unpredictable mild stress (CUMS) group. After establishment of depressive models verified by sucrose preference test, the mice in CUMS group were divided into model group, fluoxetine group and vortioxetine group. The antidepressive effect of vortioxetine was analyzed by tail suspension test, forced swim test and open field test. The levels of cAMP were detected using a commercial ELISA kit, and the expressions of pCREB and brain-derived neurotrophic factor (BDNF) were evaluated with Western blotting.. Vortioxetine significantly shortened the immobility time of the depressive mice in tail suspension test and forced swim test without affecting the locomotor activity of the mice in open fields, suggesting the antidepressive effect of against depression in mice. Vortioxetine significantly increased the levels of cAMP and promoted the expression of pCREB and BDNF in the hippocampus of the mice (P<0.01).. Vortioxetine improves the behaviors of mice with depression possibly by affecting the cAMP/CREB/BDNF signal pathway.

Topics: Animals; Antidepressive Agents; Brain-Derived Neurotrophic Factor; Cyclic AMP; Cyclic AMP Response Element-Binding Protein; Depression; Disease Models, Animal; Hippocampus; Immobilization; Locomotion; Mice; Random Allocation; Signal Transduction; Swimming; Vortioxetine

Selective serotonin (5-HT, SERT) reuptake inhibitors (SSRIs) are the most commonly prescribed treatments for depression. However, they have delayed efficacy and can induce side-effects that can encourage discontinuation. Recently, agents have been developed, including vortioxetine (Trintellix), that augment SERT blockade with interactions at other targets. At therapeutic doses, vortioxetine interacts with SERT as well as 5-HT

Topics: Animals; Antidepressive Agents; Behavior, Animal; Depression; Disease Models, Animal; Hindlimb Suspension; Hippocampus; Mice; Neurogenesis; Piperazines; Serotonin; Serotonin Plasma Membrane Transport Proteins; Sulfides; Synaptosomes; Vortioxetine

The mechanisms mediating ketamine's antidepressant effect have only been partly resolved. Recent preclinical reports implicate serotonin (5-hydroxytryptamine; 5-HT) in the antidepressant-like action of ketamine. Vortioxetine is a multimodal-acting antidepressant that is hypothesized to exert its therapeutic activity through 5-HT reuptake inhibition and modulation of several 5-HT receptors.. The objective of this study was to evaluate the therapeutic-like profiles of S-ketamine, vortioxetine, and the serotonin reuptake inhibitor fluoxetine in response to manipulation of 5-HT tone.. Flinders Sensitive Line (FSL) rats, a genetic model of depression, were depleted of 5-HT by repeated administration of 4-chloro-DL-phenylalanine methyl ester HCl (pCPA). Using pCPA-pretreated and control FSL rats, we investigated the acute and sustained effects of S-ketamine (15 mg/kg), fluoxetine (10 mg/kg), or vortioxetine (10 mg/kg) on recognition memory and depression-like behavior in the object recognition task (ORT) and forced swim test (FST), respectively.. The behavioral phenotype of FSL rats was unaffected by 5-HT depletion. Vortioxetine, but not fluoxetine or S-ketamine, acutely ameliorated the memory deficits of FSL rats in the ORT irrespective of 5-HT tone. No sustained effects were observed in the ORT. In the FST, all three drugs demonstrated acute antidepressant-like activity but only S-ketamine had sustained effects. Unlike vortioxetine, the antidepressant-like responses of fluoxetine and S-ketamine were abolished by 5-HT depletion.. These observations suggest that the acute and sustained antidepressant-like effects of S-ketamine depend on endogenous stimulation of 5-HT receptors. In contrast, the acute therapeutic-like effects of vortioxetine on memory and depression-like behavior may be mediated by direct activity at 5-HT receptors.

Topics: Animals; Anti-Anxiety Agents; Antidepressive Agents; Behavior, Animal; Depressive Disorder; Disease Models, Animal; Fluoxetine; Ketamine; Locomotion; Male; Memory Disorders; Piperazines; Rats; Recognition, Psychology; Selective Serotonin Reuptake Inhibitors; Sulfides; Swimming; Vortioxetine

We previously reported that the investigational multimodal antidepressant, vortioxetine, reversed 5-HT depletion-induced memory deficits while escitalopram and duloxetine did not. The present report studied the effects of vortioxetine and the potential impact of its 5-HT1A receptor agonist and 5-HT3 receptor antagonist properties on 5-HT depletion-induced memory deficits. Recognition and spatial working memory were assessed in the object recognition (OR) and Y-maze spontaneous alternation (SA) tests, respectively. 5-HT depletion was induced in female Long-Evans rats using 4-cholro-DL-phenylalanine methyl ester HCl (PCPA) and receptor occupancies were determined by ex vivo autoradiography. Rats were acutely dosed with vortioxetine, ondansetron (5-HT3 receptor antagonist) or flesinoxan (5-HT1A receptor agonist). The effects of chronic vortioxetine administration on 5-HT depletion-induced memory deficits were also assessed. 5-HT depletion reliably impaired memory performance in both the tests. Vortioxetine reversed PCPA-induced memory deficits dose-dependently with a minimal effective dose (MED) ≤0.1mg/kg (∼80% 5-HT3 receptor occupancy; OR) and ≤3.0mg/kg (5-HT1A, 5-HT1B, 5-HT3 receptor occupancy: ∼15%, 60%, 95%) in SA. Ondansetron exhibited a MED ≤3.0μg/kg (∼25% 5-HT3 receptor occupancy; OR), but was inactive in the SA test. Flesinoxan had a MED ≤1.0mg/kg (∼25% 5-HT1A receptor occupancy; SA); only 1.0mg/kg ameliorated deficits in the NOR. Chronic p.o. vortioxetine administration significantly improved memory performance in OR and occupied 95%, 66%, and 9.5% of 5-HT3, 5-HT1B, and 5-HT1A receptors, respectively. Vortioxetine's effects on SA performance may involve 5-HT1A receptor agonism, but not 5-HT3 receptor antagonism, whereas the effects on OR performance may involve 5-HT3 receptor antagonism and 5-HT1A receptor agonism.

Topics: 8-Hydroxy-2-(di-n-propylamino)tetralin; Animals; Benzamides; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Indazoles; Maze Learning; Memory Disorders; Memory, Short-Term; Phenylalanine; Piperazines; Protein Binding; Pyridines; Rats; Rats, Long-Evans; Receptor, Serotonin, 5-HT1A; Receptors, Serotonin, 5-HT3; Recognition, Psychology; Serotonin 5-HT1 Receptor Agonists; Serotonin 5-HT3 Receptor Antagonists; Sulfides; Time Factors; Tritium; Tropanes; Vortioxetine

Depressed patients suffer from cognitive dysfunction, including memory deficits. Acute serotonin (5-HT) depletion impairs memory and mood in vulnerable patients. The investigational multimodal acting antidepressant vortioxetine is a 5-HT3, 5-HT7 and 5-HT1D receptor antagonist, 5-HT1B receptor partial agonist, 5-HT1A receptor agonist and 5-HT transporter (SERT) inhibitor that enhances memory in normal rats in novel object recognition (NOR) and conditioned fear (Mørk et al., 2013). We hypothesized that vortioxetine's 5-HT receptor mechanisms are involved in its memory effects, and therefore investigated these effects in 5-HT depleted rats. Four injections of the irreversible tryptophan hydroxylase inhibitor 4-chloro-dl-phenylalanine methyl ester hydrochloride (PCPA, 86mg/kg, s.c.) induced 5-HT depletion, as measured in hippocampal homogenate and microdialysate. The effects of acute challenge with vortioxetine or the 5-HT releaser fenfluramine on extracellular 5-HT were measured in PCPA-treated and control rats. PCPA's effects on NOR and spontaneous alternation (SA) performance were assessed along with the effects of acute treatment with 5-hydroxy-l-tryptophan (5-HTP), vortioxetine, the selective 5-HT reuptake inhibitor escitalopram, or the 5-HT norepinephrine reuptake inhibitor duloxetine. SERT occupancies were estimated by ex vivo autoradiography. PCPA depleted central 5-HT by >90% in tissue and microdialysate, and impaired NOR and SA performance. Restoring central 5-HT with 5-HTP reversed these deficits. At similar SERT occupancies (>90%) vortioxetine, but not escitalopram or duloxetine, restored memory performance. Acute fenfluramine significantly increased extracellular 5-HT in control and PCPA-treated rats, while vortioxetine did so only in control rats. Thus, vortioxetine restores 5-HT depletion impaired memory performance in rats through one or more of its receptor activities.

Topics: 5-Hydroxytryptophan; Animals; Carbidopa; Citalopram; Disease Models, Animal; Dose-Response Relationship, Drug; Duloxetine Hydrochloride; Exploratory Behavior; Female; Hippocampus; Maze Learning; Memory Disorders; Phenylalanine; Piperazines; Protein Binding; Rats; Rats, Long-Evans; Recognition, Psychology; Selective Serotonin Reuptake Inhibitors; Serotonin; Sulfides; Thiophenes; Vortioxetine

Current treatments for depression, including serotonin-specific reuptake inhibitors (SSRIs), are only partially effective, with a high incidence of residual symptoms, relapse, and treatment resistance. Loss of cognitive flexibility, a component of depression, is associated with dysregulation of the prefrontal cortex. Reversal learning, a form of cognitive flexibility, is impaired by chronic stress, a risk factor for depression, and the stress-induced impairment in reversal learning is sensitive to chronic SSRI treatment, and is mimicked by serotonin (5-HT) depletion. Vortioxetine, a novel, multimodal-acting antidepressant, is a 5-HT3, 5-HT7 and 5-HT1D receptor antagonist, a 5-HT1B receptor partial agonist, a 5-HT1A receptor agonist, and inhibits the 5-HT transporter. Using adult male rats, we first investigated the direct effects of vortioxetine, acting at post-synaptic 5-HT receptors, on reversal learning that was compromised by 5-HT depletion using 4-chloro-DL-phenylalanine methyl ester hydrochloride (PCPA), effectively eliminating any contribution of 5-HT reuptake blockade. PCPA induced a reversal learning impairment that was alleviated by acute or sub-chronic vortioxetine administration, suggesting that post-synaptic 5-HT receptor activation contributes to the effects of vortioxetine. We then investigated the effects of chronic dietary administration of vortioxetine on reversal learning that had been compromised in intact animals exposed to chronic intermittent cold (CIC) stress, to assess vortioxetine's total pharmacological effect. CIC stress impaired reversal learning, and chronic vortioxetine administration prevented the reversal-learning deficit. Together, these results suggest that the direct effect of vortioxetine at 5-HT receptors may contribute to positive effects on cognitive flexibility deficits, and may enhance the effect of 5-HT reuptake blockade.

Topics: Analysis of Variance; Animals; Anti-Anxiety Agents; Attention; Autoradiography; Body Weight; Cold Temperature; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Learning Disabilities; Male; Phenylalanine; Piperazines; Rats; Rats, Sprague-Dawley; Reversal Learning; Serotonin; Stress, Psychological; Sulfides; Vortioxetine