Involvement of 5-HT3 receptors in the action of vortioxetine in rat brain: focus on glutamatergic and GABAergic neurotransmission

The antidepressant vortioxetine is a 5-HT3-R, 5-HT7-R and 5-HT1D-R antagonist, 5-HT1B-R partial agonist, 5-HT1A-R agonist, and serotonin (5-HT) transporter (SERT) inhibitor. Vortioxetine occupies all targets at high therapeutic doses and only SERT and 5-HT3-R at low doses. Vortioxetine increases extracellular monoamine concentrations in rat forebrain more than selective serotonin reuptake inhibitors (SSRI) and shows pro-cognitive activity in preclinical models. Given its high affinity for 5-HT3-R (Ki = 3.7 nM), selectively expressed in GABA interneurons, we hypothesized that vortioxetine may disinhibit glutamatergic and monoaminergic neurotransmission following 5-HT3-R blockade. Here we assessed vortioxetine effect on pyramidal neuron activity and extracellular 5-HT concentration using in vivo extracellular recordings of rat medial prefrontal cortex (mPFC) pyramidal neurons and microdialysis in mPFC and ventral hippocampus (vHPC). Vortioxetine, but not escitalopram, increased pyramidal neuron discharge in mPFC. This effect was prevented by SR57227A (5-HT3-R agonist) and was mimicked by ondansetron (5-HT3-R antagonist) and by escitalopram/ondansetron combinations. In microdialysis experiments, ondansetron augmented the 5-HT-enhancing effect of escitalopram in mPFC and vHPC. Local ondansetron in vHPC augmented escitalopram effect, indicating the participation of intrinsic mechanisms. Since 5-HT neurons express GABAB receptors, we examined their putative involvement in controlling 5-HT release after 5-HT3-R blockade. Co-perfusion of baclofen (but not muscimol) reversed the increased 5-HT levels produced by vortioxetine and escitalopram/ondansetron combinations in vHPC. The present results suggest that vortioxetine increases glutamatergic and serotonergic neurotransmission in rat forebrain by blocking 5-HT3 receptors in GABA interneurons.This work was supported by a grant from Lundbeck A/S and by grants SAF 2012-35183 and SAF 2015-68346-P from the Spanish Ministry of Economy and Competitiveness, co-financed by European Regional Development Fund (ERDF) and grant PI12/00156 (Instituto de Salud Carlos III, co-financed by European Regional Development Fund (ERDF). Support from the Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) and Generalitat de Catalunya Grup de Recerca Consolidat, (2014SGR798) is also acknowledged. FA and PC are PI and co-PI from a grant from Lundbeck A/S to examine the mechanism of action of vortioxetine. FA has also received lecture and consultation fees from Lundbeck A/S and is scientific advisor to Neurolixis. CS is a Lundbeck A/S employee.Peer reviewe

Subchronic vortioxetine enhances cortical activity

Vortioxetine (VOR) is a multimodal antidepressant drug. VOR is a 5-HT3-R, 5-HT7-R and 5-HT1D-R antagonist, 5-HT1B-R partial agonist, 5-HT1A-R agonist, and serotonin transporter (SERT) inhibitor. VOR shows pro-cognitive activity in animal models and beneficial effects on cognitive dysfunction in major depressive patients. Here we compared the effects of 14-day treatments with VOR and escitalopram (ESC, selective serotonin reuptake inhibitor) on neuronal activity in the medial prefrontal cortex (mPFC). Ten groups of rats (5 standard, 5 depleted of 5-HT with p-chlorophenylalanine-pCPA-, used as model of cognitive impairment) were fed with control food or with two doses of VOR-containing food. Four groups were implanted with minipumps delivering vehicle or ESC 10 mg/kg·day s.c. The two VOR doses enable occupation by VOR of SERT+5-HT3-R and all targets, respectively, and correspond to SERT occupancies in patients treated with 5 and 20 VOR mg/day, respectively. Putative pyramidal neurons (n=985) were recorded extracellularly in the mPFC of anesthetized rats. Sub-chronic VOR administration (but not ESC) significantly increased neuronal discharge in standard and 5-HT-depleted conditions, with a greater effect of the low VOR dose in standard rats. VOR increased neuronal discharge in infralimbic (IL) and prelimbic (PrL) cortices. Hence, oral VOR doses evoking SERT occupancies similar to those in treated patients increase mPFC neuronal discharge. The effect in 5-HT-depleted rats cannot be explained by an antagonist action of VOR at 5-HT3-R and suggests a non-canonical interaction of VOR with 5-HT3-R. These effects may underlie the superior pro-cognitive efficacy of VOR compared with SSRIs in animal modelsSupported by Lundbeck A/S and grants: SAF2015-68346-P (Spanish Ministry of Economy and Competitiveness, co-financed by European Regional Development Fund (ERDF)) and PI12/00156 (Instituto de Salud Carlos III, co-financed by European Regional Development Fund (ERDF)). Support from the Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) and Generalitat de Catalunya Grup de Recerca Consolidat, 2014SGR798 is also acknowledgedPeer reviewe

In vivo electrophysiological study of the targeting of 5-HT3 receptor-expressing cortical interneurons by the multimodal antidepressant, vortioxetine

This study was supported by an educational grant from H. Lundbeck A/S.The antidepressant vortioxetine has high affinity for the ionotropic 5-HT3 receptor (5-HT3R) as well as other targets including the 5-HT transporter. The procognitive effects of vortioxetine have been linked to altered excitatory:inhibitory balance in cortex. Thus, vortioxetine purportedly inhibits cortical 5-HT3R-expressing interneurons (5-HT3R-INs) to disinhibit excitatory pyramidal neurons. The current study determined for the first time, the effect of vortioxetine on the in vivo firing of putative 5-HT3R-INs whilst simultaneously recording pyramidal neuron activity using cortical slow-wave oscillations as a readout. Extracellular single unit and local field potential recordings were made in superficial layers of the prefrontal cortex of urethane-anaesthetised rats. 5-HT3R-INs were identified by a short-latency excitation evoked by electrical stimulation of the dorsal raphe nucleus (DRN). Juxtacellular-labelling found such neurons had the morphological and immunohistochemical properties of 5-HT3R-INs; basket cell or bipolar cell morphology, expression of 5-HT3R-IN markers, and parvalbumin-immunonegative. Vortioxetine inhibited the short-latency DRN-evoked excitation of 5-HT3R-INs and simultaneously decreased cortical slow wave oscillations, indicative of pyramidal neuron activation. Likewise, the 5-HT3R antagonist ondansetron inhibited the short-latency DRN-evoked excitation of 5-HT3R-INs. However unlike vortioxetine, ondansetron did not decrease cortical slow-wave oscillations suggesting a dissociation between this effect and inhibition of 5-HT3R-INs. The 5-HT reuptake inhibitor escitalopram had no consistent effect on any electrophysiological parameter measured. Overall, the current findings suggest that vortioxetine simultaneously inhibits (DRN-evoked) 5-HT3R-INs and excites pyramidal neurons, thereby changing the excitatory:inhibitory balance in cortex. However, under the current experimental conditions these two effects were dissociable with only the former likely involving a 5-HT3R-mediated mechanism.Publisher PDFPeer reviewe

Reversal of age-associated cognitive deficits is accompanied by increased plasticity-related gene expression after chronic antidepressant administration in middle-aged mice

AbstractCognitive decline occurs during healthy aging, even in middle-aged subjects, via mechanisms that could include reduced stem cell proliferation, changed growth factor expression and/or reduced expression of synaptic plasticity genes. Although antidepressants alter these mechanisms in young rodents, their effects in older animals are unclear. In middle-aged mice, we examined the effects of a selective serotonin reuptake inhibitor (fluoxetine) and a multimodal antidepressant (vortioxetine) on cognitive and affective behaviors, brain stem cell proliferation, growth factor and gene expression. Twelve-month-old female C57BL/6 mice exhibited impaired visuospatial memory in the novel object placement (location) task associated with reduced expression of several plasticity-related genes. Chronic treatment with vortioxetine, but not fluoxetine, improved visuospatial memory and reduced depression-like behavior in the forced swim test in middle-aged mice. Vortioxetine, but not fluoxetine, increased hippocampal expression of several neuroplasticity-related genes in middle-aged mice (e.g., Nfkb1, Fos, Fmr1, Camk2a, Arc, Shank1, Nlgn2, and Rab3a). Neither drug reversed the age-associated decrease in stem cell proliferation. Hippocampal growth factor levels were not consistent with behavioral outcomes. Thus, a change in the expression of multiple genes involved in neuronal plasticity by antidepressant treatment was associated with improved cognitive function and a reduction in depression-like behavior in middle-aged mice

HSV suppression reduces seminal HIV-1 levels in HIV-1/HSV-2 co-infected men who have sex with men.

OBJECTIVES: Suppressive herpes simplex virus (HSV) therapy can decrease plasma, cervical, and rectal HIV-1 levels in HIV-1/HSV-2 co-infected persons. We evaluated the effect of HSV-2 suppression on seminal HIV-1 levels. DESIGN: Twenty antiretroviral therapy (ART)-naive HIV-1/HSV-2 men who have sex with men (MSM) in Lima, Peru, with CD4 >200 cells/microl randomly received valacyclovir 500 mg twice daily or placebo for 8 weeks, then the alternative regimen for 8 weeks after a 2-week washout. Peripheral blood and semen specimens were collected weekly. Anogenital swab specimens for HSV DNA were self-collected daily and during clinic visits. METHODS: HIV-1 RNA was quantified in seminal and blood plasma by TaqMan real-time polymerase chain reaction (RT-PCR) or Roche Amplicor Monitor assays. HSV and seminal cytomegalovirus (CMV) were quantified by RT-PCR. Linear mixed models examined differences within participants by treatment arm. RESULTS: Median CD4 cell count of participants was 424 cells/microl. HIV-1 was detected in 71% of 231 semen specimens. HSV was detected from 29 and 4.4% of swabs on placebo and valacyclovir, respectively (P < 0.001). Valacyclovir significantly reduced the proportion of days with detectable seminal HIV-1 (63% during valacyclovir vs. 78% during placebo; P = 0.04). Seminal HIV-1 quantity was 0.25 log10 copies/ml lower [95% confidence interval (CI) -0.40 to -0.10; P = 0.001] during the valacyclovir arm compared with placebo, a 44% reduction. CD4 cell count (P = 0.32) and seminal cellular CMV quantity (P = 0.68) did not predict seminal plasma HIV-1 level. CONCLUSIONS: Suppressive valacyclovir reduced seminal HIV-1 levels in HIV-1/HSV-2 co-infected MSM not receiving ART. The significance of this finding will be evaluated in a trial with HIV-1 transmission as the outcome

Diagnosis and treatment of urticaria and angioedema: a worldwide perspective

Urticaria and angioedema are common clinical conditions representing a major concern for physicians and patients alike. The World Allergy Organization (WAO), recognizing the importance of these diseases, has contributed to previous guidelines for the diagnosis and management of urticaria. The Scientific and Clinical Issues Council of WAO proposed the development of this global Position Paper to further enhance the clinical management of these disorders through the participation of renowned experts from all WAO regions of the world. Sections on definition and classification, prevalence, etiology and pathogenesis, diagnosis, treatment, and prognosis are based on the best scientific evidence presently available. Additional sections devoted to urticaria and angioedema in children and pregnant women, quality of life and patient-reported outcomes, and physical urticarias have been incorporated into this document. It is expected that this article will supplement recent international guidelines with the contribution of an expert panel designated by the WAO, increasing awareness of the importance of urticaria and angioedema in medical practice and will become a useful source of information for optimum patient management worldwide

Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p&lt;0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (&lt;1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (&lt;1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline

Vortioxetine, a novel antidepressant with multimodal activity: Review of preclinical and clinical data

© 2014 Elsevier Inc. Vortioxetine, a novel antidepressant for the treatment of major depressive disorder (MDD), is a 5-HT3, 5-HT7 and 5-HT1D receptor antagonist, 5-HT1B receptor partial agonist, 5-HT1A receptor agonist and serotonin (5-HT) transporter (SERT) inhibitor. Here we review its preclinical and clinical properties and discuss translational aspects. Vortioxetine increases serotonergic, noradrenergic, dopaminergic, cholinergic, histaminergic and glutamatergic neurotransmission in brain structures associated with MDD. These multiple effects likely derive from its interaction with 5-HT-receptor-mediated negative feedback mechanisms controlling neuronal activity. In particular, 5-HT3 receptors may play a prominent role, since their blockade i) increases pyramidal neuron activity by removing 5-HT3 receptor-mediated excitation of GABA interneurons, and ii) augments SSRI effects on extracellular 5-HT. However, modulation of the other 5-HT receptor subtypes also likely contributes to vortioxetine's pharmacological effects. Preclinical animal models reveal differences from SSRIs and SNRIs, including antidepressant-like activity, increased synaptic plasticity and improved cognitive function. Vortioxetine had clinical efficacy in patients with MDD: 11 placebo-controlled studies (including one in elderly) with efficacy in 8 (7 positive, 1 supportive), 1 positive active comparator study plus a positive relapse prevention study. In two positive studies, vortioxetine was superior to placebo in pre-defined cognitive outcome measures. The clinically effective dose range (5-20 mg/day) spans ~50 to >80% SERT occupancy. SERT and 5-HT3 receptors are primarily occupied at 5 mg, while at 20 mg, all targets are likely occupied at functionally relevant levels. The side-effect profile is similar to that of SSRIs, with gastrointestinal symptoms being most common, and a low incidence of sexual dysfunction and sleep disruption possibly ascribed to vortioxetine's receptor modulation.Support to FA from the Ministerio de Economía y Competitividad (SAF 2012-35183), co-financed by the European Regional Development Fund (ERDF), the Generalitat de Catalunya (2009-SGR220) and the Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) is acknowledgedPeer Reviewe