S 47445 counteracts the behavioral manifestations and hippocampal neuroplasticity changes in bulbectomized mice.

S 47445 is a positive allosteric modulator of glutamate AMPA-type receptors that possesses procognitive, neurotrophic and enhancing synaptic plasticity properties. Its chronic administration promotes antidepressant- and anxiolytic-like effects in different rodent models of depression. We have evaluated the behavioral effects of S 47445 in the bilateral olfactory bulbectomy mice model (OB) and the adaptive changes in those proteins associated to brain neuroplasticity (BDNF and mTOR pathway).

Drug-receptor kinetics and sigma-1 receptor affinity differentiate clinically evaluated histamine H receptor antagonists.

The histamine H receptor is a G protein-coupled receptor (GPCR) drug target that is highly expressed in the CNS, where it acts as both an auto- and hetero-receptor to regulate neurotransmission. As such, it has been considered as a relevant target in disorders as varied as Alzheimer's disease, schizophrenia, neuropathic pain and attention deficit hyperactivity disorder. A range of competitive antagonists/inverse agonists have progressed into clinical development, with pitolisant approved for the treatment of narcolepsy.

α- and β-Adrenoreceptor-Mediated Efficacy of the Atypical Antidepressant Agomelatine Combined With Gabapentin to Suppress Allodynia in Neuropathic Rats With Ligated Infraorbital or Sciatic Nerve.

Previous data showed that neuropathic pain induced by mechanical lesion of peripheral nerves has specific characteristics and responds differently to alleviating drugs at cephalic versus extracephalic level. This is especially true for tricyclic antidepressants currently used for alleviating neuropathic pain in humans which are less effective against cephalic neuropathic pain. Whether this also applies to the antidepressant agomelatine, with its unique pharmacological properties as MT/MT melatonin receptor agonist and 5-HT/5-HT serotonin receptor antagonist, has been investigated in two rat models of neuropathic pain.

S 47445 Produces Antidepressant- and Anxiolytic-Like Effects through Neurogenesis Dependent and Independent Mechanisms.

Glutamatergic dysfunctions are observed in the pathophysiology of depression. The glutamatergic synapse as well as the AMPA receptor's (AMPAR) activation may represent new potential targets for therapeutic intervention in the context of major depressive disorders. S 47445 is a novel AMPARs positive allosteric modulator (AMPA-PAM) possessing procognitive, neurotrophic properties and enhancing synaptic plasticity.

Increased Aβ-α7-like nicotinic acetylcholine receptor complex level in lymphocytes is associated with apolipoprotein E4-driven Alzheimer's disease pathogenesis.

Background: The apolipoprotein E ε4 (APOE4) genotype is a prominent late-onset Alzheimer's disease (AD) risk factor. ApoE4 disrupts memory function in rodents and may contribute to both plaque and tangle formation.

Methods: Coimmunoprecipitation and Western blot detection were used to determine: 1) the effects of select fragments from the apoE low-density lipoprotein (LDL) binding domain and recombinant apoE subtypes on amyloid beta (Aβ)-α7 nicotinic acetylcholine receptor (α7nAChR) interaction and tau phosphorylation in rodent brain synaptosomes; and 2) the level of Aβ-α7nAChR complexes in matched controls and patients with mild cognitive impairment (MCI) and dementia due to AD with known APOE genotypes.

Upregulation of neurotrophins by S 47445, a novel positive allosteric modulator of AMPA receptors in aged rats.

At molecular levels, it has been shown that aging is associated with alterations in neuroplastic mechanisms. In this study, it was examined if the altered expression of neurotrophins observed in aged rats could be corrected by a chronic treatment with S 47445 (1-3-10mg/kg, p.o.

Effect of agomelatine on memory deficits and hippocampal gene expression induced by chronic social defeat stress in mice.

Chronic stress is known to induce not only anxiety and depressive-like phenotypes in mice but also cognitive impairments, for which the action of classical antidepressant compounds remains unsatisfactory. In this context, we investigated the effects of chronic social defeat stress (CSDS) on anxiety-, social- and cognitive-related behaviors, as well as hippocampal Bdnf, synaptic plasticity markers (PSD-95, Synaptophysin, Spinophilin, Synapsin I and MAP-2), and epigenetic modifying enzymes (MYST2, HDAC2, HDAC6, MLL3, KDM5B, DNMT3B, GADD45B) gene expression in C57BL/6J mice. CSDS for 10 days provoked long-lasting anxious-like phenotype in the open field and episodic memory deficits in the novel object recognition test.

S 38093, a histamine H antagonist/inverse agonist, promotes hippocampal neurogenesis and improves context discrimination task in aged mice.

Strategies designed to increase adult hippocampal neurogenesis (AHN) may have therapeutic potential for reversing memory impairments. H receptor antagonists/inverse agonists also may be useful for treating cognitive deficits. However, it remains unclear whether these ligands have effects on AHN.

The Synergistic Enhancing-Memory Effect of Donepezil and S 38093 (a Histamine H Antagonist) Is Mediated by Increased Neural Activity in the Septo-hippocampal Circuitry in Middle-Aged Mice.

Donepezil, an acetylcholinesterase inhibitor, induces only moderate symptomatic effects on memory in Alzheimer's disease patients. An alternative strategy for treatment of cognitive symptoms could be to act simultaneously on both histaminergic and cholinergic pathways, to create a synergistic effect. To that aim, 14 month old C57/Bl6 mice were administered per oesophagy during nine consecutive days with Donepezil (at 0.

Agomelatine: a new opportunity to reduce neuropathic pain-preclinical evidence.

Antidepressants are first-line treatments of neuropathic pain but not all these drugs are really effective. Agomelatine is an antidepressant with a novel mode of action, acting as an MT1/MT2 melatonergic receptor agonist and a 5-HT2C receptor antagonist that involves indirect norepinephrine release. Melatonin, serotonin, and norepinephrine have been involved in the pathophysiology of neuropathic pain.

Isoform-Specific Biased Agonism of Histamine H3 Receptor Agonists.

The human histamine H receptor (hHR) is subject to extensive gene splicing that gives rise to a large number of functional and nonfunctional isoforms. Despite the general acceptance that G protein-coupled receptors can adopt different ligand-induced conformations that give rise to biased signaling, this has not been studied for the HR; further, it is unknown whether splice variants of the same receptor engender the same or differential biased signaling. Herein, we profiled the pharmacology of histamine receptor agonists at the two most abundant hHR splice variants (hHR and hHR) across seven signaling endpoints.

Agomelatine affects rat suprachiasmatic nucleus neurons via melatonin and serotonin receptors.

Aims: The hypothalamic suprachiasmatic nucleus (SCN), which functions as a circadian pacemaker in mammals, is influenced by melatonin and serotonin. Agomelatine, which acts as an antidepressant and can synchronize disturbed circadian rhythms, displays a unique mechanism of action involving both melatonergic agonist and 5-HT2C antagonist properties. This study investigated the dose-dependent effects of agomelatine, melatonin and a selective 5-HT2C receptor antagonist, S32006, on SCN neurons in an in vitro slice preparation.

Evaluation of the effects of therapeutic and supratherapeutic doses of agomelatine on the QT/QTc interval: a phase I, randomized, double-blind, placebo-controlled and positive-controlled, crossover thorough QT/QTc study conducted in healthy volunteers.

: The effects of the antidepressant agomelatine up to a supratherapeutic dose (400 mg, single dose) on the QT corrected (QTc) interval were assessed in a randomized, double-blind, placebo- and positive-controlled, crossover thorough QT/QTc study in young healthy volunteers (29 males and 31 females). The primary criterion was the study of male or female population-derived QT-corrected interval (QTcP). The main analysis on the QTcP demonstrated that among the 10 postdose measurement times planned, the largest 1-sided 95% confidence interval upper bound of the difference between agomelatine 50 mg and placebo-adjusted means, and 1 of the differences between agomelatine 400 mg and placebo-adjusted means were both strictly inferior to the 10 millisecond upper-bound threshold of regulatory concern.

The effects of antidepressant treatment in prenatally stressed rats support the glutamatergic hypothesis of stress-related disorders.

Abnormalities of synaptic transmission in the hippocampus represent an integral part of the altered programming triggered by early life stress, which enhances the vulnerability to stress-related disorders in the adult life. Rats exposed to prenatal restraint stress (PRS) develop enduring biochemical and behavioral changes characteristic of an anxious/depressive-like phenotype. Most neurochemical abnormalities in PRS rats are found in the ventral hippocampus, a region that encodes memories related to stress and emotions.

Like melatonin, agomelatine (S20098) increases the amplitude of oscillations of two clock outputs: melatonin and temperature rhythms.

Depression and biological rhythms disturbances are strongly associated. Agomelatine is an antidepressant with melatoninergic MT1-MT2 agonist and serotoninergic 5-HT2c antagonist properties. Both melatonin and 5-HT are known to modulate circadian rhythmicity controlled by the endogenous clock located in the suprachiasmatic nuclei (SCN).

Chronic treatment with agomelatine or venlafaxine reduces depolarization-evoked glutamate release from hippocampal synaptosomes.

Background: Growing compelling evidence from clinical and preclinical studies has demonstrated the primary role of alterations of glutamatergic transmission in cortical and limbic areas in the pathophysiology of mood disorders. Chronic antidepressants have been shown to dampen endogenous glutamate release from rat hippocampal synaptic terminals and to prevent the marked increase of glutamate overflow induced by acute behavioral stress in frontal/prefrontal cortex. Agomelatine, a new antidepressant endowed with MT1/MT2 agonist and 5-HT2C serotonergic antagonist properties, has shown efficacy at both preclinical and clinical levels.

Pharmacological or genetic blockade of the dopamine D3 receptor increases cell proliferation in the hippocampus of adult mice.

Dopamine plays an important role in cellular processes controlling the functional and structural plasticity of neurons, as well as their generation and proliferation, both in the developing and the adult brain. The precise roles of individual dopamine receptors subtypes in adult neurogenesis remain poorly defined, although D3 receptors are known to be involved in neurogenesis in the subventricular zone. By contrast, very few studies have addressed the influence of dopamine and D3 receptors upon neurogenesis in the subgranular zone of the hippocampus, an issue addressed herein employing constitutive D3 receptor knockout mice, or chronic exposure to the preferential D3 receptor antagonist, S33138.

The antidepressant agomelatine inhibits stress-mediated changes in amino acid efflux in the rat hippocampus and amygdala.

Agomelatine is a potent melatonergic (MT1 and MT2) receptor agonist and 5HT(2C) antagonist that is an effective antidepressant in animal models of depression and in patients suffering from depression. Our recent studies revealed that acute restraint stress increases extracellular levels of glutamate and GABA and that these increases in amino acid efflux are inhibited by some but not all antidepressants. In view of the increasing evidence supporting a role of amino acids in the pathology of depression, the current study examined whether acute stress-mediated changes in glutamate and GABA neurotransmission are modulated by agomelatine.

Chronic agomelatine treatment corrects the abnormalities in the circadian rhythm of motor activity and sleep/wake cycle induced by prenatal restraint stress in adult rats.

Agomelatine is a novel antidepressant acting as an MT1/MT2 melatonin receptor agonist/5-HT2C serotonin receptor antagonist. Because of its peculiar pharmacological profile, this drug caters the potential to correct the abnormalities of circadian rhythms associated with mood disorders, including abnormalities of the sleep/wake cycle. Here, we examined the effect of chronic agomelatine treatment on sleep architecture and circadian rhythms of motor activity using the rat model of prenatal restraint stress (PRS) as a putative 'aetiological' model of depression.

Agomelatine (S20098) modulates the expression of cytoskeletal microtubular proteins, synaptic markers and BDNF in the rat hippocampus, amygdala and PFC.

Rationale: Agomelatine is described as a novel and clinical effective antidepressant drug with melatonergic (MT(1)/MT(2)) agonist and 5-HT(2C) receptor antagonist properties. Previous studies suggest that modulation of neuronal plasticity and microtubule dynamics may be involved in the treatment of depression.

Objective: The present study investigated the effects of agomelatine on microtubular, synaptic and brain-derived neurotrophic factor (BDNF) proteins in selected rat brain regions.

Agomelatine suppresses locomotor hyperactivity in olfactory bulbectomised rats: a comparison to melatonin and to the 5-HT(2c) antagonist, S32006.

The novel melatonergic agonist/5-HT(2C) antagonist agomelatine displays robust antidepressant properties in humans and is active in pre-clinical models predictive of antidepressant effects. In this study, we investigated its potential influence on the locomotor hyperactivity displayed by olfactory bulbectomised rats, a putative measure of potential antidepressant activity. In addition, we compared the actions of agomelatine to those of melatonin and S32006, a selective antagonist at 5-HT(2C) receptors.

Absence of psychostimulant effects of a supratherapeutic dose of tianeptine: a placebo-controlled study versus methylphenidate in young healthy volunteers.

Objective: The primary objective of the present study was to assess the potential psychostimulant effect of a single oral supratherapeutic dose of tianeptine (75 mg in 1 shot) in young healthy volunteers compared with methylphenidate (40 mg) and placebo.

Method: Eighteen healthy young male and female volunteers with no history of psychostimulant abuse completed this balanced, crossover, placebo-controlled study. Subjective and behavioral effects were assessed before treatment and 1, 2, 3, 4, and 8 hours after drug intake.

Chronic stress and antidepressant agomelatine induce region-specific changes in synapsin I expression in the rat brain.

The antidepressant agomelatine acts as a melatonergic receptor (MT(1)/MT(2)) agonist and 5-HT(2C) receptor antagonist. Agomelatine has demonstrated efficacy in treating depression, but its neurobiological effects merit further investigation. Preclinical studies reported that agomelatine enhances adult hippocampal neurogenesis and increases expression of several neuroplasticity-associated molecules.