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Papp M, Gruca P, Litwa E, Lason M, Newman-Tancredi A, Depoortère R. The 5-HT1A receptor biased agonists, NLX-204 and NLX-101, like ketamine, elicit rapid-acting antidepressant activity in the rat chronic mild stress model via cortical mechanisms. J Psychopharmacol 2024:2698811241254832. [PMID: 38825869 DOI: 10.1177/02698811241254832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
BACKGROUND The highly selective 5-HT1A serotonin receptor "biased" agonists NLX-101 and NLX-204 display, like ketamine, potent and efficacious rapid-acting antidepressant (RAAD) activity in the rat chronic mild stress (CMS) model with systemic (i.p.) administration. They rapidly (within 1 day) reverse anhedonia (i.e., CMS-induced sucrose consumption deficit), attenuate working memory deficit (novel object recognition: NOR), and decrease anxiety behavior in the elevated-plus maze (EPM). AIMS Here, we sought to explore the contribution of prefrontal cortex (PFC) 5-HT1A receptor activation in the RAAD activity of NLX compounds. RESULTS/OUTCOMES In male Wistar rats, unilateral PFC microinjections of NLX-204 and NLX-101 (16 µg), like ketamine (10 µg), reproduced the effects of their systemic administration: they reversed CMS-induced sucrose consumption deficit, attenuated anxiety (EPM), and reduced working memory deficits (NOR). In addition, unilateral PFC microinjections of the selective 5-HT1A antagonist, WAY-100,635 (2 µg), attenuated the beneficial effects of systemic NLX-204 and NLX-101 (0.16 mg/kg i.p.) in the sucrose intake and NOR models, indicating that these compounds exert their RAAD activity specifically through activation of PFC 5-HT1A receptors. CONCLUSIONS/INTERPRETATION These data indicate that 5-HT1A receptor biased agonists share with ketamine a common neuroanatomical site for RAAD activity, which can be obtained not only by targeting glutamatergic/NMDA neurotransmission (ketamine's primary mechanism of action) but also by activating 5-HT1A receptors, as is the case for the NLX compounds. The present observations also reinforce the notion that biased agonism at 5-HT1A receptors constitutes a promising strategy to achieve RAAD effects, with additional benefits against cognitive deficits and anxiety in depressed patients, without ketamine's troublesome side effects.
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Affiliation(s)
- Mariusz Papp
- Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Piotr Gruca
- Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Ewa Litwa
- Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Magdalena Lason
- Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
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Payet JM, Stevens L, Russo AM, Jaehne EJ, van den Buuse M, Kent S, Lowry CA, Baratta MV, Hale MW. The Role of Dorsal Raphe Nucleus Serotonergic Systems in Emotional Learning and Memory in Male BALB/c Mice. Neuroscience 2023; 534:1-15. [PMID: 37852412 DOI: 10.1016/j.neuroscience.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are the first-line pharmacological treatment for a variety of anxiety-, trauma- and stressor-related disorders. Although they are efficacious, therapeutic improvements require several weeks of treatment and are often associated with an initial exacerbation of symptoms. The dorsal raphe nucleus (DR) has been proposed as an important target for the modulation of emotional responses and the therapeutic effects of SSRIs. Using a fear-conditioning paradigm we aimed to understand how SSRIs affect emotional learning and memory, and their effects on serotonergic circuitry. Adult male BALB/c mice were treated with vehicle (n = 16) or the SSRI fluoxetine (18 mg/kg/d) acutely (n = 16), or chronically (21d, n = 16), prior to fear conditioning. Treatment was stopped, and half of the mice (n = 8/treatment group) were exposed to cued fear memory recall 72 h later. Activation of DR serotonergic neurons during fear conditioning (Experiment 1) or fear memory recall (Experiment 2), was measured using dual-label immunohistochemistry for Tph2 and c-Fos. Acute and chronic fluoxetine treatment reduced associative fear learning without affecting memory recall and had opposite effects on anxiety-like behaviour. Acute fluoxetine decreased serotonergic activity in the DR, while chronic treatment led to serotonergic activity that was indistinguishable from that of control levels in DRD and DRV subpopulations. Chronic fluoxetine facilitated fear extinction, which was associated with rostral DRD inhibition. These findings provide further evidence that SSRIs can alter aspects of learning and memory processes and are consistent with a role for discrete populations of DR serotonergic neurons in regulating fear- and anxiety-related behaviours.
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Affiliation(s)
- Jennyfer M Payet
- Department of Psychology, Counselling and Therapy, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Laura Stevens
- Department of Psychology, Counselling and Therapy, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Adrian M Russo
- Department of Psychology, Counselling and Therapy, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Emily J Jaehne
- Department of Psychology, Counselling and Therapy, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia; Department of Psychiatry, School of Clinical Sciences, Monash University, Clayton, Victoria, Australia
| | - Maarten van den Buuse
- Department of Psychology, Counselling and Therapy, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Stephen Kent
- Department of Psychology, Counselling and Therapy, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Christopher A Lowry
- Department of Integrative Physiology and Centre for Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Michael V Baratta
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Matthew W Hale
- Department of Psychology, Counselling and Therapy, School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia.
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Groenink L, Verdouw PM, Zhao Y, Ter Heegde F, Wever KE, Bijlsma EY. Pharmacological modulation of conditioned fear in the fear-potentiated startle test: a systematic review and meta-analysis of animal studies. Psychopharmacology (Berl) 2023; 240:2361-2401. [PMID: 36651922 PMCID: PMC10593622 DOI: 10.1007/s00213-022-06307-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 12/21/2022] [Indexed: 01/19/2023]
Abstract
RATIONALE AND OBJECTIVES Fear conditioning is an important aspect in the pathophysiology of anxiety disorders. The fear-potentiated startle test is based on classical fear conditioning and over the years, a broad range of drugs have been tested in this test. Synthesis of the available data may further our understanding of the neurotransmitter systems that are involved in the expression of conditioned fear. METHODS Following a comprehensive search in Medline and Embase, we included 68 research articles that reported on 103 drugs, covering 56 different drug classes. The systematic review was limited to studies using acute, systemic drug administration in naive animals. RESULTS Qualitative data synthesis showed that most clinically active anxiolytics, but not serotonin-reuptake inhibitors, reduced cued fear. Anxiogenic drugs increased fear potentiation in 35% of the experiments, reduced fear potentiation in 29% of the experiments, and were without effect in 29% of the experiments. Meta-analyses could be performed for five drug classes and showed that benzodiazepines, buspirone, 5-HT1A agonists, 5-HT1A antagonists, and mGluR2,3 agonists reduced cued conditioned fear. The non-cued baseline startle response, which may reflect contextual anxiety, was only significantly reduced by benzodiazepines and 5-HT1A antagonists. No associations were found between drug effects and methodological characteristics, except for strain. CONCLUSIONS The fear-potentiated startle test appears to have moderate to high predictive validity and may serve as a valuable tool for the development of novel anxiolytics. Given the limited available data, the generally low study quality and high heterogeneity additional studies are warranted to corroborate the findings of this review.
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Affiliation(s)
- Lucianne Groenink
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands.
| | - P Monika Verdouw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Yulong Zhao
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Freija Ter Heegde
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Kimberley E Wever
- Department of Anaesthesiology, Pain and Palliative Medicine, Radboud Institute for Health Sciences, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Elisabeth Y Bijlsma
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
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Effects of a psychedelic 5-HT2A receptor agonist on anxiety-related behavior and fear processing in mice. Neuropsychopharmacology 2022; 47:1304-1314. [PMID: 35449450 PMCID: PMC9117291 DOI: 10.1038/s41386-022-01324-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 03/12/2022] [Accepted: 04/06/2022] [Indexed: 11/08/2022]
Abstract
Psychedelic-assisted psychotherapy gained considerable interest as a novel treatment strategy for fear-related mental disorders but the underlying mechanism remains poorly understood. The serotonin 2A (5-HT2A) receptor is a key target underlying the effects of psychedelics on emotional arousal but its role in fear processing remains controversial. Using the psychedelic 5-HT2A/5-HT2C receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) and 5-HT2A receptor knockout (KO) mice we investigated the effect of 5-HT2A receptor activation on emotional processing. We show that DOI administration did not impair performance in a spontaneous alternation task but reduced anxiety-like avoidance behavior in the elevated plus maze and elevated zero maze tasks. Moreover, we found that DOI did not block memory recall but diminished fear expression in a passive avoidance task. Likewise, DOI administration reduced fear expression in an auditory fear conditioning paradigm, while it did not affect retention of fear extinction when administered prior to extinction learning. The effect of DOI on fear expression was abolished in 5-HT2A receptor KO mice. Administration of DOI induced a significant increase of c-Fos expression in specific amygdalar nuclei. Moreover, local infusion of the 5-HT2A receptor antagonist M100907 into the amygdala reversed the effect of systemic administration of DOI on fear expression while local administration of DOI into the amygdala was sufficient to suppress fear expression. Our data demonstrate that activation of 5-HT2A receptors in the amygdala suppresses fear expression but provide no evidence for an effect on retention of fear extinction.
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Newman-Tancredi A, Depoortère RY, Kleven MS, Kołaczkowski M, Zimmer L. Translating biased agonists from molecules to medications: Serotonin 5-HT 1A receptor functional selectivity for CNS disorders. Pharmacol Ther 2021; 229:107937. [PMID: 34174274 DOI: 10.1016/j.pharmthera.2021.107937] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/01/2021] [Accepted: 06/17/2021] [Indexed: 12/18/2022]
Abstract
Biased agonism (or "functional selectivity") at G-protein-coupled receptors has attracted rapidly increasing interest as a means to improve discovery of more efficacious and safer pharmacotherapeutics. However, most studies are limited to in vitro tests of cellular signaling and few biased agonists have progressed to in vivo testing. As concerns 5-HT1A receptors, which exert a major control of serotonergic signaling in diverse CNS regions, study of biased agonism has previously been limited by the poor target selectivity and/or partial agonism of classically available ligands. However, a new generation of highly selective, efficacious and druggable agonists has advanced the study of biased agonism at this receptor and created new therapeutic opportunities. These novel agonists show differential properties for G-protein signaling, cellular signaling (particularly pERK), electrophysiological effects, neurotransmitter release, neuroimaging by PET and pharmacoMRI, and behavioral tests of mood, motor activity and side effects. Overall, NLX-101 (a.k.a. F15599) exhibits preferential activation of cortical and brain stem 5-HT1A receptors, whereas NLX-112 (a.k.a. befiradol or F13640) shows prominent activation of 5-HT1A autoreceptors in Raphe nuclei and in regions associated with motor control. Accordingly, NLX-101 is potently active in rodent models of depression and respiratory control, whereas NLX-112 shows promising activity in models of Parkinson's disease across several species - rat, marmoset and macaque. Moreover, NLX-112 has also been labeled with 18F to produce the first agonist PET radiopharmaceutical (known as [18F]-F13640) for investigation of the active state of 5-HT1A receptors in rodent, primate and human. The structure-functional activity relationships of biased agonists have been investigated by receptor modeling and novel compounds have been identified which exhibit increased affinity at 5-HT1A receptors and new profiles of cellular signaling bias, notably for β-arrestin recruitment versus pERK. Taken together, the data suggest that 5-HT1A receptor biased agonists constitute potentially superior pharmacological agents for treatment of CNS disorders involving serotonergic mechanisms.
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Affiliation(s)
| | | | | | | | - Luc Zimmer
- Université Claude Bernard Lyon1, Lyon, France; Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS-INSERM, France
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Stettler PR, F Antunes D, Taborsky B. The serotonin 1A receptor modulates the social behaviour within groups of a cooperatively-breeding cichlid. Horm Behav 2021; 129:104918. [PMID: 33428923 DOI: 10.1016/j.yhbeh.2020.104918] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/06/2020] [Accepted: 12/23/2020] [Indexed: 11/24/2022]
Abstract
The neurotransmitter serotonin (5-HT) reduces aggressive behaviour in a number of vertebrates, and the 5-HT1A receptor is known to be involved in this regulation. However, the role of this receptor in the modulation of sociopositive behaviour remains largely unknown. Here we investigated the role of the 5-HT1A receptor in the regulation of aggressive, submissive and affiliative behaviour in the cooperatively-breeding cichlid Neolamprologus pulcher. In two experiments, we performed intramuscular injections of a 5-HT1A agonist (8-OH-DPAT) and antagonist (Way-100635) followed by recordings of social behaviour of injected fish within their social groups. We determined the concentrations and post-injection times when the drugs had the greatest effect on social behaviour. We recorded spontaneous social behaviour in both experiments. In the second experiment we also recorded behaviour after social groups received a territorial challenge by live presentations of either conspecifics or egg predators. The 5-HT1A agonist caused an increase in aggression and a decrease in submission and affiliation, whereas the antagonist had the opposite effects. Thus, the 5-HT1A receptor plays an important regulatory role not only for aggressive but also sociopositive behaviour.
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Affiliation(s)
- Pia R Stettler
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, 3032 Hinterkappelen, Switzerland.
| | - Diogo F Antunes
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, 3032 Hinterkappelen, Switzerland.
| | - Barbara Taborsky
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, 3032 Hinterkappelen, Switzerland.
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Depoortere R, Bardin L, Auclair AL, Bruins Slot LA, Newman-Tancredi A. Marble Burying in NMRI Male Mice Is Preferentially Sensitive to Pre- Versus Postsynaptic 5-HT1A Receptor Biased Agonists. Pharmacology 2020; 106:114-118. [PMID: 32950991 DOI: 10.1159/000509729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/19/2020] [Indexed: 11/19/2022]
Abstract
Obsessive compulsive disorder (OCD) is a psychiatric disorder characterized by excessive and repetitive thoughts and gestures, mainly treated pharmacologically with selective serotonin reuptake inhibitors (SSRIs). The marble burying test in mice is commonly used to model OCD and has been shown to be sensitive to SSRIs, which decrease burying behavior. The activity of SSRIs in this model is mediated through activation of 5-hydroxytryptamine (5-HT) 1A receptors, but the respective implication of pre- versus postsynaptic 5-HT1A receptors has not been elucidated. Here, we investigated marble burying behavior by male NMRI mice following acute administration of 3 biased agonists, which preferentially activate presynaptic 5-HT1A receptors (F13714) or postsynaptic receptors (NLX-101) or which exhibit balanced activation of both pre- and postsynaptic 5-HT1A receptors (NLX-112). When administered at the dose of 2.5 mg/kg i.p., all 3 biased agonists completely or nearly completely abolished marble burying behavior. However, they varied in their potency with minimal effective doses of 0.16, 0.63, and 2.5 mg/kg i.p., for F13714, NLX-112, and NLX-101, respectively. The selective 5-HT1A receptor antagonist, WAY100,635 was inactive up to 2.5 mg/kg. These results suggest that marble burying behavior in male NMRI mice is preferentially sensitive to activation of pre- versus postsynaptic 5-HT1A receptors. Moreover, they suggest that targeting 5-HT1A receptors with biased agonists could provide an innovative therapeutic approach to combat OCD.
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Role of 5-HT1A Receptor in the Anxiolytic-Relaxant Effects of Bergamot Essential Oil in Rodent. Int J Mol Sci 2020; 21:ijms21072597. [PMID: 32283606 PMCID: PMC7177770 DOI: 10.3390/ijms21072597] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/04/2020] [Accepted: 04/07/2020] [Indexed: 12/20/2022] Open
Abstract
The essential oil obtained by the fresh fruit of Citrus bergamia Risso et Poiteau is used worldwide in aromatherapy to reduce pain, facilitate sleep induction, and/or minimize the effects of stress-induced anxiety. Preclinical pharmacological data demonstrate that bergamot essential oil (BEO) modulates specific neurotransmissions and shows an anxiolytic-relaxant effect not superimposable to that of the benzodiazepine diazepam, suggesting that neurotransmissions, other than GABAergic, could be involved. Several studies on essential oils indicate a role for serotonergic (5-HT) neurotransmission in anxiety. Interestingly, among serotonergic receptors, the 5-HT1A subtype seems to play a key role in the control of anxiety. Here, we report that modulation of the 5-HT1A receptor by selective agonist ((±)8-OH-DPAT) or antagonist (WAY-100635) may influence some of the anxiolytic-relaxant effects of BEO in Open Field and Elevated Plus Maze tests.
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Depoortère R, Papp M, Gruca P, Lason-Tyburkiewicz M, Niemczyk M, Varney MA, Newman-Tancredi A. Cortical 5-hydroxytryptamine 1A receptor biased agonist, NLX-101, displays rapid-acting antidepressant-like properties in the rat chronic mild stress model. J Psychopharmacol 2019; 33:1456-1466. [PMID: 31290370 DOI: 10.1177/0269881119860666] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND NLX-101 (also known as F15599) is a highly selective and efficacious 'biased' agonist at cortical 5-hydroxytryptamine 1A (5-HT1A) heteroreceptors. In rodents, it possesses marked antidepressant-like activity, potently and completely abolishing immobility in the forced swim test (FST) with extended duration of action. METHODS We investigated the antidepressant-like activity of NLX-101 using the rat chronic mild stress (CMS) model of depression, considered to have a higher translational potential than the FST, as it possesses construct, face and predictive validity. The effects of CMS and repeated NLX-101 treatment were tested using sucrose consumption (a measure of anhedonia), novel object recognition (NOR; a measure of working memory) and elevated plus maze (EPM; a measure of anxiety) tests. RESULTS NLX-101 reversed the CMS-induced decrease of sucrose intake on day 1 of testing, with full reversal observed at the dose of 0.16 mg/kg and a less pronounced but still significant effect at 0.04 mg/kg, both given twice a day intraperitoneally. The effects of NLX-101 were maintained over the 2 week treatment period and persisted for four weeks following cessation of treatment. In the NOR test, both doses of NLX-101 rescued the deficit in discrimination index caused by CMS, without any effect on locomotor activity. However, NLX-101 had no effect on the reduction of open-arms entries produced by CMS in the EPM model. In control, non-stressed rats, NLX-101 produced non-significant effects in all three models. CONCLUSIONS NLX-101 displayed efficacious activity in the CMS test, with more rapid (1 day) antidepressant-like effects than pharmacological compounds tested previously under the same experimental conditions. These observations suggest that biased agonist targeting of cortical 5-HT1A receptors constitutes a promising strategy to achieve rapid-acting and sustained antidepressant effects.
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Affiliation(s)
| | - Mariusz Papp
- Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Piotr Gruca
- Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | | | - Monika Niemczyk
- Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
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Sartori SB, Singewald N. Novel pharmacological targets in drug development for the treatment of anxiety and anxiety-related disorders. Pharmacol Ther 2019; 204:107402. [PMID: 31470029 DOI: 10.1016/j.pharmthera.2019.107402] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/19/2019] [Indexed: 12/24/2022]
Abstract
Current medication for anxiety disorders is suboptimal in terms of efficiency and tolerability, highlighting the need for improved drug treatments. In this review an overview of drugs being studied in different phases of clinical trials for their potential in the treatment of fear-, anxiety- and trauma-related disorders is presented. One strategy followed in drug development is refining and improving compounds interacting with existing anxiolytic drug targets, such as serotonergic and prototypical GABAergic benzodiazepines. A more innovative approach involves the search for compounds with novel mechanisms of anxiolytic action using the growing knowledge base concerning the relevant neurocircuitries and neurobiological mechanisms underlying pathological fear and anxiety. The target systems evaluated in clinical trials include glutamate, endocannabinoid and neuropeptide systems, as well as ion channels and targets derived from phytochemicals. Examples of promising novel candidates currently in clinical development for generalised anxiety disorder, social anxiety disorder, panic disorder, obsessive compulsive disorder or post-traumatic stress disorder include ketamine, riluzole, xenon with one common pharmacological action of modulation of glutamatergic neurotransmission, as well as the neurosteroid aloradine. Finally, compounds such as D-cycloserine, MDMA, L-DOPA and cannabinoids have shown efficacy in enhancing fear-extinction learning in humans. They are thus investigated in clinical trials as an augmentative strategy for speeding up and enhancing the long-term effectiveness of exposure-based psychotherapy, which could render chronic anxiolytic drug treatment dispensable for many patients. These efforts are indicative of a rekindled interest and renewed optimism in the anxiety drug discovery field, after decades of relative stagnation.
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Affiliation(s)
- Simone B Sartori
- Institute of Pharmacy, Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck (CMBI), Leopold Franzens University Innsbruck, Innsbruck, Austria
| | - Nicolas Singewald
- Institute of Pharmacy, Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck (CMBI), Leopold Franzens University Innsbruck, Innsbruck, Austria.
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