151
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Hillhouse TM, Porter JH, Negus SS. Comparison of antidepressant-like and abuse-related effects of phencyclidine in rats. Drug Dev Res 2014; 75:479-88. [PMID: 25315690 DOI: 10.1002/ddr.21228] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/06/2014] [Indexed: 01/23/2023]
Abstract
Preclinical Research N-methyl-D-aspartate (NMDA) receptor antagonists, such as ketamine, have emerged as novel candidate treatments for major depressive disorder, but abuse potential of these agents is a concern. The NMDA antagonist phencyclidine has known abuse liability but undefined efficacy as an antidepressant. To further evaluate the relationship between antidepressant-like and abuse-related effects of NMDA antagonists, this study evaluated the effects of phencyclidine (1.0-10.0 mg/kg) in male Sprague-Dawley rats responding under two procedures that have been used to assess antidepressant-like effects (differential-reinforcement-of-low-rate [DRL] 72 s schedule of food reinforcement; n = 9) and abuse-related drug effects (intracranial self-stimulation [ICSS]; n = 6). Under the DRL 72 s schedule, phencyclidine (10.0 mg/kg) increased reinforcers and decreased responses without shifting the peak location of the interresponse time (IRT) distribution. Ketamine (10.0 mg/kg) also increased reinforcers and decreased responses, but unlike phencyclidine, it produced a rightward shift in the peak location of the IRT distribution. The 10.0 mg/kg phencyclidine dose that decreased DRL 72 s responding also decreased rates of ICSS for 50 min after its administration; however, abuse-related ICSS facilitation was observed at later times (100-300 min) or after a lower phencyclidine dose (3.2 mg/kg). These results suggest that phencyclidine produces weaker antidepressant-like effects, but stronger abuse-related effects than ketamine in these procedures.
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Affiliation(s)
- Todd M Hillhouse
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
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152
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The role of GluN2A and GluN2B subunits on the effects of NMDA receptor antagonists in modeling schizophrenia and treating refractory depression. Neuropsychopharmacology 2014; 39:2673-80. [PMID: 24871546 PMCID: PMC4207347 DOI: 10.1038/npp.2014.123] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/22/2014] [Accepted: 05/24/2014] [Indexed: 11/08/2022]
Abstract
Paradoxically, N-methyl-D-aspartate (NMDA) receptor antagonists are used to model certain aspects of schizophrenia as well as to treat refractory depression. However, the role of different subunits of the NMDA receptor in both conditions is poorly understood. Here we used biochemical and behavioral readouts to examine the in vivo prefrontal efflux of serotonin and glutamate as well as the stereotypical behavior and the antidepressant-like activity in the forced swim test elicited by antagonists selective for the GluN2A (NVP-AAM077) and GluN2B (Ro 25-6981) subunits. The effects of the non-subunit selective antagonist, MK-801; were also studied for comparison. The administration of MK-801 dose dependently increased the prefrontal efflux of serotonin and glutamate and markedly increased the stereotypy scores. NVP-AAM077 also increased the efflux of serotonin and glutamate, but without the induction of stereotypies. In contrast, Ro 25-6981 did not change any of the biochemical and behavioral parameters tested. Interestingly, the administration of NVP-AAM077 and Ro 25-6981 alone elicited antidepressant-like activity in the forced swim test, in contrast to the combination of both compounds that evoked marked stereotypies. Our interpretation of the results is that both GluN2A and GluN2B subunits are needed to induce stereotypies, which might be suggestive of potential psychotomimetic effects in humans, but the antagonism of only one of these subunits is sufficient to evoke an antidepressant response. We also propose that GluN2A receptor antagonists could have potential antidepressant activity in the absence of potential psychotomimetic effects.
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153
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Guo J, Zhou D, Grimm SW, Bui KH. Pharmacokinetics, metabolism and excretion of [14C]-lanicemine (AZD6765), a novel low-trappingN-methyl-d-aspartic acid receptor channel blocker, in healthy subjects. Xenobiotica 2014; 45:244-55. [DOI: 10.3109/00498254.2014.966175] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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154
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Niciu MJ, Henter ID, Luckenbaugh DA, Zarate CA, Charney DS. Glutamate receptor antagonists as fast-acting therapeutic alternatives for the treatment of depression: ketamine and other compounds. Annu Rev Pharmacol Toxicol 2014; 54:119-39. [PMID: 24392693 DOI: 10.1146/annurev-pharmtox-011613-135950] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The N-methyl-D-aspartate (NMDA) receptor antagonist ketamine has rapid and potent antidepressant effects in treatment-resistant major depressive disorder and bipolar depression. These effects are in direct contrast to the more modest effects seen after weeks of treatment with classic monoaminergic antidepressants. Numerous open-label and case studies similarly validate ketamine's antidepressant properties. These clinical findings have been reverse-translated into preclinical models in an effort to elucidate ketamine's antidepressant mechanism of action, and three important targets have been identified: mammalian target of rapamycin (mTOR), eukaryotic elongation factor 2 (eEF2), and glycogen synthase kinase-3 (GSK-3). Current clinical and preclinical research is focused on (a) prolonging/maintaining ketamine's antidepressant effects, (b) developing more selective NMDA receptor antagonists free of ketamine's adverse effects, and (c) identifying predictor, mediator/moderator, and treatment response biomarkers of ketamine's antidepressant effects.
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Affiliation(s)
- Mark J Niciu
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institutes of Health/National Institute of Mental Health, Bethesda, Maryland 20814-9692;
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155
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Lanicemine: a low-trapping NMDA channel blocker produces sustained antidepressant efficacy with minimal psychotomimetic adverse effects. Mol Psychiatry 2014; 19:978-85. [PMID: 24126931 PMCID: PMC4195977 DOI: 10.1038/mp.2013.130] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/17/2013] [Accepted: 08/01/2013] [Indexed: 02/06/2023]
Abstract
Ketamine, an N-methyl-D-aspartate receptor (NMDAR) channel blocker, has been found to induce rapid and robust antidepressant-like effects in rodent models and in treatment-refractory depressed patients. However, the marked acute psychological side effects of ketamine complicate the interpretation of both preclinical and clinical data. Moreover, the lack of controlled data demonstrating the ability of ketamine to sustain the antidepressant response with repeated administration leaves the potential clinical utility of this class of drugs in question. Using quantitative electroencephalography (qEEG) to objectively align doses of a low-trapping NMDA channel blocker, AZD6765 (lanicemine), to that of ketamine, we demonstrate the potential for NMDA channel blockers to produce antidepressant efficacy without psychotomimetic and dissociative side effects. Furthermore, using placebo-controlled data, we show that the antidepressant response to NMDA channel blockers can be maintained with repeated and intermittent drug administration. Together, these data provide a path for the development of novel glutamatergic-based therapeutics for treatment-refractory mood disorders.
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156
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Griffiths JJ, Zarate CA, Rasimas JJ. Existing and novel biological therapeutics in suicide prevention. Am J Prev Med 2014; 47:S195-203. [PMID: 25145739 PMCID: PMC4143783 DOI: 10.1016/j.amepre.2014.06.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 05/27/2014] [Accepted: 06/10/2014] [Indexed: 01/15/2023]
Abstract
We summarize outcomes for several pharmacologic and neurostimulatory approaches that have been considered potential treatments to reduce suicide risk, namely, by reducing suicide deaths, attempts, and ideation in various clinical populations. Available treatments include clozapine, lithium, antidepressants, antipsychotics, electroconvulsive therapy, and transcranial magnetic stimulation. The novel repurposing of ketamine as a potential suicide risk-mitigating agent in the acute setting is also discussed. Research pathways to better understand and treat suicidal ideation and behavior from a neurobiological perspective are proposed in light of this foundation of information and the limitations and challenges inherent in suicide research. Such pathways include trials of fast-acting medications, registry approaches to identify appropriate patients for trials, identification of biomarkers, neuropsychological vulnerabilities, and endophenotypes through the study of known suicide risk-mitigating agents in hope of determining mechanisms of pathophysiology and the action of protective biological interventions.
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Affiliation(s)
| | - Carlos A Zarate
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, NIH, Bethesda, Maryland
| | - J J Rasimas
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, NIH, Bethesda, Maryland; Departments of Psychiatry and Emergency Medicine, Penn State College of Medicine, Hershey, Pennsylvania.
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157
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Faster, better, stronger: towards new antidepressant therapeutic strategies. Eur J Pharmacol 2014; 753:32-50. [PMID: 25092200 DOI: 10.1016/j.ejphar.2014.07.046] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 05/28/2014] [Accepted: 07/24/2014] [Indexed: 12/26/2022]
Abstract
Major depression is a highly prevalent disorder and is predicted to be the second leading cause of disease burden by 2020. Although many antidepressant drugs are currently available, they are far from optimal. Approximately 50% of patients do not respond to initial first line antidepressant treatment, while approximately one third fail to achieve remission following several pharmacological interventions. Furthermore, several weeks or months of treatment are often required before clinical improvement, if any, is reported. Moreover, most of the commonly used antidepressants have been primarily designed to increase synaptic availability of serotonin and/or noradrenaline and although they are of therapeutic benefit to many patients, it is clear that other therapeutic targets are required if we are going to improve the response and remission rates. It is clear that more effective, rapid-acting antidepressants with novel mechanisms of action are required. The purpose of this review is to outline the current strategies that are being taken in both preclinical and clinical settings for identifying superior antidepressant drugs. The realisation that ketamine has rapid antidepressant-like effects in treatment resistant patients has reenergised the field. Further, developing an understanding of the mechanisms underlying the rapid antidepressant effects in treatment-resistant patients by drugs such as ketamine may uncover novel therapeutic targets that can be exploited to meet the Olympian challenge of developing faster, better and stronger antidepressant drugs.
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158
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Domin H, Szewczyk B, Woźniak M, Wawrzak-Wleciał A, Śmiałowska M. Antidepressant-like effect of the mGluR5 antagonist MTEP in an astroglial degeneration model of depression. Behav Brain Res 2014; 273:23-33. [PMID: 25043733 DOI: 10.1016/j.bbr.2014.07.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/08/2014] [Accepted: 07/11/2014] [Indexed: 10/25/2022]
Abstract
The glutamatergic predominance in the excitatory-inhibitory balance is postulated to be involved in the pathogenesis of depression. Such imbalance may be induced by astrocyte ablation which reduces glutamate uptake and increases glutamate level in the synaptic cleft. In the present study, we tried to ascertain whether astroglial degeneration in the prefrontal cortex could serve as an animal model of depression and whether inhibition of glutamatergic transmission by the mGluR5 antagonist MTEP could have antidepressant potential. Astrocytic toxins l-or dl-alpha-aminoadipic acid (AAA), 100μg/2μl, were microinjected, bilaterally into the rat medial prefrontal cortex (PFC) on the first and second day of experiment. MTEP (10mg/kg) or imipramine (30mg/kg) were administered on the fifth day. Following administration of MTEP or imipramine the forced swim test (FST) was performed for assessment of depressive-like behavior. The brains were taken out for analysis on day eight. The astrocytic marker, glial fibrillary acidic protein (GFAP) was quantified in PFC by Western blot method and by stereological counting of immunohistochemically stained sections. Both l-AAA and dl-AAA induced a significant increase in immobility time in the FST. This effect was reversed by imipramine, which indicates depressive-like effects of these toxins. A significant decrease in GFAP (about 50%) was found after l-AAA. Both the behavioral and GFAP level changes were prevented by MTEP injection. The obtained results indicate that the degeneration of astrocytes in the PFC by l-AAA may be a useful animal model of depression and suggest antidepressant potential of MTEP.
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Affiliation(s)
- Helena Domin
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Bernadeta Szewczyk
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Monika Woźniak
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Anika Wawrzak-Wleciał
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Maria Śmiałowska
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland.
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159
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Wallach J, Kavanagh PV, McLaughlin G, Morris N, Power JD, Elliott SP, Mercier MS, Lodge D, Morris H, Dempster NM, Brandt SD. Preparation and characterization of the ‘research chemical’ diphenidine, its pyrrolidine analogue, and their 2,2-diphenylethyl isomers. Drug Test Anal 2014; 7:358-67. [DOI: 10.1002/dta.1689] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 06/07/2014] [Accepted: 06/08/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Jason Wallach
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy; University of the Sciences; Philadelphia PA 19104 USA
| | - Pierce V. Kavanagh
- Department of Pharmacology and Therapeutics, School of Medicine; Trinity Centre for Health Sciences, St. James Hospital; Dublin 8 Ireland
| | - Gavin McLaughlin
- Department of Pharmacology and Therapeutics, School of Medicine; Trinity Centre for Health Sciences, St. James Hospital; Dublin 8 Ireland
- Department of Life and Physical Sciences, School of Science; Athlone Institute of Technology; Dublin Road, Athlone, Co. Westmeath Ireland
| | - Noreen Morris
- Department of Life and Physical Sciences, School of Science; Athlone Institute of Technology; Dublin Road, Athlone, Co. Westmeath Ireland
| | - John D. Power
- Department of Pharmacology and Therapeutics, School of Medicine; Trinity Centre for Health Sciences, St. James Hospital; Dublin 8 Ireland
| | - Simon P. Elliott
- ROAR Forensics; Malvern Hills Science Park; Geraldine Road WR14 3SZ UK
| | - Marion S. Mercier
- Department of Physiology and Pharmacology; University of Bristol; Dorothy Hodgkin Building, Whitson Street Bristol BS1 3NY UK
| | - David Lodge
- Department of Physiology and Pharmacology; University of Bristol; Dorothy Hodgkin Building, Whitson Street Bristol BS1 3NY UK
| | - Hamilton Morris
- Department of Anthropology; The New School for Social Research; 66 West 12th Street NY 10011 New York USA
| | - Nicola M. Dempster
- School of Pharmacy and Biomolecular Sciences; Liverpool John Moores University; Byrom Street Liverpool L3 3AF UK
| | - Simon D. Brandt
- School of Pharmacy and Biomolecular Sciences; Liverpool John Moores University; Byrom Street Liverpool L3 3AF UK
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160
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Pochwat B, Pałucha-Poniewiera A, Szewczyk B, Pilc A, Nowak G. NMDA antagonists under investigation for the treatment of major depressive disorder. Expert Opin Investig Drugs 2014; 23:1181-92. [PMID: 24818801 DOI: 10.1517/13543784.2014.918951] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Mood disorders, including depression, are becoming increasingly prevalent in the developed world. Furthermore, treatment of depression therapeutics, mainly influencing the serotonergic and adrenergic systems, is considered insufficient. The original NMDA-glutamate hypothesis mechanism of antidepressant action was first proposed ∼ 20 years ago. Since then, a number of preclinical and clinical studies have examined its rationale. AREAS COVERED This review highlights the recent clinical evidence for the use of functional NMDA receptor antagonists as antidepressants. Furthermore, the authors present the mechanism(s) of antidepressant action derived mostly from preclinical paradigms. EXPERT OPINION Currently, clinical studies mostly use ketamine (a noncompetitive high-potency NMDA antagonist) as an agent for rapid relief of depressive symptoms. However, due to the ketamine-induced psychotomimetic effects, new NMDA receptor antagonists (modulators) are continuously being introduced for rapid antidepressant action, especially for use in treatment-resistant patients. Recent clinical reports for the use of CP-101,606, MK-0657 (selective GluN2B subunit NMDA receptor antagonists), GLYX-13 and d-cycloserine (glycine site partial agonists) are optimistic but await further support.
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Affiliation(s)
- Bartłomiej Pochwat
- Institute of Pharmacology, Polish Academy of Sciences , Smętna 12, PL 31-343 Kraków , Poland
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161
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Neill JC, Harte MK, Haddad PM, Lydall ES, Dwyer DM. Acute and chronic effects of NMDA receptor antagonists in rodents, relevance to negative symptoms of schizophrenia: a translational link to humans. Eur Neuropsychopharmacol 2014; 24:822-35. [PMID: 24287012 DOI: 10.1016/j.euroneuro.2013.09.011] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 06/06/2013] [Accepted: 09/26/2013] [Indexed: 12/11/2022]
Abstract
Negative symptoms of schizophrenia remain an unmet clinical need as they are common, persistent, respond poorly to existing treatments and lead to disability. Blunted affect, alogia, asociality, anhedonia and avolition are regarded as key negative symptoms despite DSM-IV-TR specifying a more limited range. The key to development of improved therapies is improved animal models that mimic the human condition in terms of behaviour and pathology and that predict efficacy of novel treatments in patients. Accumulating evidence shows that NMDA receptor (NMDAR) antagonists mimic cognitive deficits of relevance to schizophrenia in animals, along with associated pathological changes. This review examines evidence for the ability of NMDAR antagonists to mimic anhedonia and asociality, two negative symptoms of schizophrenia, in animals. The use of various species, paradigms and treatment regimens are reviewed. We conclude that sub-chronic treatment with NMDAR antagonists, typically PCP, induces social withdrawal in animals but not anhedonia. NMDAR antagonists have further effects in paradigms such as motivational salience that may be useful for mimicking other aspects of negative symptoms but these require further development. Sub-chronic treatment regimens of NMDAR antagonists also have some neurobiological effects of relevance to negative symptoms. It is our view that a sub-chronic treatment regime with NMDAR antagonists, particularly PCP, with animals tested following a wash-out period and in a battery of tests to assess certain behaviours of relevance to negative symptoms and social withdrawal (the animal equivalent of asociality) is valuable. This will enhance our understanding of the psycho and neuropathology of specific negative symptom domains and allow early detection of novel pharmacological targets.
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Affiliation(s)
- Joanna C Neill
- Manchester Pharmacy School, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK.
| | - Michael K Harte
- Manchester Pharmacy School, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK
| | - Peter M Haddad
- Neuroscience and Psychiatry Unit, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK
| | - Emma S Lydall
- Public Health Wales, Unit 1 Charnwood Court, Heol Billingsley, Parc Nantgarw, Cardiff CF15 7QZ, UK
| | - Dominic M Dwyer
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK
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162
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Luckenbaugh DA, Niciu MJ, Ionescu DF, Nolan NM, Richards EM, Brutsche NE, Guevara S, Zarate CA. Do the dissociative side effects of ketamine mediate its antidepressant effects? J Affect Disord 2014; 159:56-61. [PMID: 24679390 PMCID: PMC4065787 DOI: 10.1016/j.jad.2014.02.017] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/05/2014] [Accepted: 02/06/2014] [Indexed: 01/22/2023]
Abstract
BACKGROUND The N-methyl-d-aspartate receptor antagonist ketamine has rapid antidepressant effects in major depression. Psychotomimetic symptoms, dissociation and hemodynamic changes are known side effects of ketamine, but it is unclear if these side effects relate to its antidepressant efficacy. METHODS Data from 108 treatment-resistant inpatients meeting criteria for major depressive disorder and bipolar disorder who received a single subanesthetic ketamine infusion were analyzed. Pearson correlations were performed to examine potential associations between rapid changes in dissociation and psychotomimesis with the Clinician-Administered Dissociative States Scale (CADSS) and Brief Psychiatric Rating Scale (BPRS), respectively, manic symptoms with Young Mania Rating Scale (YMRS), and vital sign changes, with percent change in the 17-item Hamilton Depression Rating scale (HDRS) at 40 and 230min and Days 1 and 7. RESULTS Pearson correlations showed significant association between increased CADSS score at 40min and percent improvement with ketamine in HDRS at 230min (r=-0.35, p=0.007) and Day 7 (r=-0.41, p=0.01). Changes in YMRS or BPRS Positive Symptom score at 40min were not significantly correlated with percent HDRS improvement at any time point with ketamine. Changes in systolic blood pressure, diastolic blood pressure, and pulse were also not significantly related to HDRS change. LIMITATIONS Secondary data analysis, combined diagnostic groups, potential unblinding. CONCLUSIONS Among the examined mediators of ketamine׳s antidepressant response, only dissociative side effects predicted a more robust and sustained antidepressant. Prospective, mechanistic investigations are critically needed to understand why intra-infusion dissociation correlates with a more robust antidepressant efficacy of ketamine.
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Affiliation(s)
| | | | | | | | | | | | | | - Carlos A. Zarate
- Correspondence to: Experimental Therapeutics & Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health (NIMH), National Institutes of Health (NIH), Building 10, CRC Room 7-534210 Center Drive, Bethesda, MD 20892, USA. Tel.: +1 301 451 0861; fax: +1 301 480 8792. (C.A. Zarate)
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163
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Dysfunctional astrocytic and synaptic regulation of hypothalamic glutamatergic transmission in a mouse model of early-life adversity: relevance to neurosteroids and programming of the stress response. J Neurosci 2014; 33:19534-54. [PMID: 24336719 DOI: 10.1523/jneurosci.1337-13.2013] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Adverse early-life experiences, such as poor maternal care, program an abnormal stress response that may involve an altered balance between excitatory and inhibitory signals. Here, we explored how early-life stress (ELS) affects excitatory and inhibitory transmission in corticotrophin-releasing factor (CRF)-expressing dorsal-medial (mpd) neurons of the neonatal mouse hypothalamus. We report that ELS associates with enhanced excitatory glutamatergic transmission that is manifested as an increased frequency of synaptic events and increased extrasynaptic conductance, with the latter associated with dysfunctional astrocytic regulation of glutamate levels. The neurosteroid 5α-pregnan-3α-ol-20-one (5α3α-THPROG) is an endogenous, positive modulator of GABAA receptors (GABAARs) that is abundant during brain development and rises rapidly during acute stress, thereby enhancing inhibition to curtail stress-induced activation of the hypothalamic-pituitary-adrenocortical axis. In control mpd neurons, 5α3α-THPROG potently suppressed neuronal discharge, but this action was greatly compromised by prior ELS exposure. This neurosteroid insensitivity did not primarily result from perturbations of GABAergic inhibition, but rather arose functionally from the increased excitatory drive onto mpd neurons. Previous reports indicated that mice (dams) lacking the GABAAR δ subunit (δ(0/0)) exhibit altered maternal behavior. Intriguingly, δ(0/0) offspring showed some hallmarks of abnormal maternal care that were further exacerbated by ELS. Moreover, in common with ELS, mpd neurons of δ(0/0) pups exhibited increased synaptic and extrasynaptic glutamatergic transmission and consequently a blunted neurosteroid suppression of neuronal firing. This study reveals that increased synaptic and tonic glutamatergic transmission may be a common maladaptation to ELS, leading to enhanced excitation of CRF-releasing neurons, and identifies neurosteroids as putative early regulators of the stress neurocircuitry.
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164
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Naughton M, Clarke G, O'Leary OF, Cryan JF, Dinan TG. A review of ketamine in affective disorders: current evidence of clinical efficacy, limitations of use and pre-clinical evidence on proposed mechanisms of action. J Affect Disord 2014; 156:24-35. [PMID: 24388038 DOI: 10.1016/j.jad.2013.11.014] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 11/19/2013] [Accepted: 11/21/2013] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Recent research has seen low-dose ketamine emerge as a novel, rapid-acting antidepressant. Ketamine, an N-methy-d-aspartate (NMDA) receptor antagonist, leads to effects on the glutamatergic system and abnormalities in this neurotransmittor system are present in depression. This article aims to (1) review the clinical literature on low-dose ketamine as a rapid-acting antidepressant in affective disorders, (2) provide a critical overview of the limitations of ketamine and research attempts to overcome these (3) discuss the proposed mechanisms of action of ketamine and (4) point towards future research directions. METHOD The electronic database Pubmed, Web of Science and sciencedirect were searched using the keywords: ketamine, N-methyl-d-aspartate receptor antagonist, rapid-acting antidepressant, depression, treatment-resistant depression, bipolar depression, suicidal ideation, electroconvulsive therapy, mechanism of action. RESULT The literature demonstrates evidence supporting a rapid-acting antidepressant effect of low-dose intravenous ketamine in major depressive disorder, in bipolar depression and in depression with suicidal ideation. There are mixed results as to whether ketamine leads to a reduction in time to remission in patients undergoing electroconvulsive therapy (ECT). Efforts to unravel ketamine's therapeutic mechanism of action have implicated the mammalian target of rapamycin (mTOR)-dependent synapse formation in the rat prefrontal cortex, eukaryotic elongation factor 2 phosphorylation (p-eEF2) and glycogen synthase kinase (GSK-3). Ketamine's limiting factors are the transient nature of its antidepressant effect and concerns regarding abuse, and research efforts to overcome these are reviewed. CONCLUSION Current and future research studies are using ketamine as a promising tool to evaluate the glutamatergic neurotransmittor system to learn more about the pathophysiology of depression and develop more specific rapid-acting antidepressant treatments.
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Affiliation(s)
- Marie Naughton
- Department of Psychiatry, University College Cork, Western Road, Cork City, Cork, Ireland.
| | - Gerard Clarke
- Department of Psychiatry, University College Cork, Western Road, Cork City, Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
| | - Olivia F O'Leary
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
| | - John F Cryan
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
| | - Timothy G Dinan
- Department of Psychiatry, University College Cork, Western Road, Cork City, Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
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165
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Finlay C, Duty S. Therapeutic potential of targeting glutamate receptors in Parkinson's disease. J Neural Transm (Vienna) 2014; 121:861-80. [PMID: 24557498 DOI: 10.1007/s00702-014-1176-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/05/2014] [Indexed: 12/28/2022]
Abstract
Glutamate plays a complex role in many aspects of Parkinson's disease including the loss of dopaminergic neurons, the classical motor symptoms as well as associated non-motor symptoms and the treatment-related side effect, L-DOPA-induced dyskinesia. This widespread involvement opens up possibilities for glutamate-based therapies to provide a more rounded approach to treatment than is afforded by current dopamine replacement therapies. Beneficial effects of blocking postsynaptic glutamate transmission have already been noted in a range of preclinical studies using antagonists of NMDA receptors or negative allosteric modulators of metabotropic glutamate receptor 5 (mGlu5), while positive allosteric modulators of mGlu4 in particular, although at an earlier stage of investigation, also look promising. This review addresses each of the key features of Parkinson's disease in turn, summarising the contribution glutamate makes to that feature and presenting an up-to-date account of the potential for drugs acting at ionotropic or metabotropic glutamate receptors to provide relief. Whilst only a handful of these have progressed to clinical trials to date, notably NMDA and NR2B antagonists against motor symptoms and L-DOPA-induced dyskinesia, with mGlu5 negative allosteric modulators also against L-DOPA-induced dyskinesia, the mainly positive outcomes of these trials, coupled with supportive preclinical data for other strategies in animal models of Parkinson's disease and L-DOPA-induced dyskinesia, raise cautious optimism that a glutamate-based therapeutic approach will have significant impact on the treatment of Parkinson's disease.
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Affiliation(s)
- Clare Finlay
- Wolfson Centre for Age-Related Diseases, King's College London, WW1.28. Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
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166
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Hasselmann HWW. Ketamine as antidepressant? Current state and future perspectives. Curr Neuropharmacol 2014; 12:57-70. [PMID: 24533016 PMCID: PMC3915350 DOI: 10.2174/1570159x113119990043] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/01/2013] [Accepted: 07/09/2013] [Indexed: 12/26/2022] Open
Abstract
Major depressive disorder (MDD) is a serious mental disorder that ranks among the major causes of disease burden. Standard medical treatment targeting cerebral monoamines often provides only insufficient symptom relief and fails in approximately every fifth patient. The complexity of MDD therefore, reflects more than monoaminergic dysregulation. Initial research argues the case for excessive glutamate levels, suggesting that antiglutamatergic drugs might be useful in treating MDD. Ketamine is a non-selective, high-affinity N-methyl-D-aspartate receptor (NMDAR) antagonist most commonly used in pediatric and animal surgery. In the past, ketamine has gained popularity because of its ability to rapidly elevate mood, even in treatment-resistant and bipolar depression. However, there are still many obstacles before widespread clinical approval of ketamine treatment could become reality. In this review, ketamine's powerful antidepressant effects are discussed and further research necessary for therapeutic application is outlined. NMDAR antagonists provide an entirely new way of treating the manifold appearances of depression that should not be left unused.
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Affiliation(s)
- H W W Hasselmann
- Research Master Programme Cognitive and Clinical Neurosciences, Maastricht University, Universiteitssingel 40, 6229 ER Maastricht, The Netherlands
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167
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De Maricourt P, Jay T, Goncalvès P, Lôo H, Gaillard R. Effet antidépresseur de la kétamine : revue de la littérature sur les mécanismes d’action de la kétamine. Encephale 2014; 40:48-55. [DOI: 10.1016/j.encep.2013.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 09/04/2013] [Indexed: 12/27/2022]
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168
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Niciu MJ, Henter ID, Sanacora G, Zarate CA. Glial abnormalities in substance use disorders and depression: does shared glutamatergic dysfunction contribute to comorbidity? World J Biol Psychiatry 2014; 15:2-16. [PMID: 24024876 PMCID: PMC4180366 DOI: 10.3109/15622975.2013.829585] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Preclinical and clinical research in neuropsychiatric disorders, particularly mood and substance use disorders, have historically focused on neurons; however, glial cells-astrocytes, microglia, and oligodendrocytes - also play key roles in these disorders. METHODS Peer-reviewed PubMed/Medline articles published through December 2012 were identified using the following keyword combinations: glia, astrocytes, oligodendrocytes/glia, microglia, substance use, substance abuse, substance dependence, alcohol, opiate, opioid, cocaine, psychostimulants, stimulants, and glutamate. RESULTS Depressive and substance use disorders are highly comorbid, suggesting a common or overlapping aetiology and pathophysiology. Reduced astrocyte cell number occurs in both disorders. Altered glutamate neurotransmission and metabolism - specifically changes in the levels/activity of transporters, receptors, and synaptic proteins potentially related to synaptic physiology - appear to be salient features of both disorders. Glial cell pathology may also underlie the pathophysiology of both disorders via impaired astrocytic production of neurotrophic factors. Microglial/neuroinflammatory pathology is also evident in both depressive and substance use disorders. Finally, oligodendrocyte impairment decreases myelination and impairs expression of myelin-related genes in both substance use and depressive disorders. CONCLUSIONS Glial-mediated glutamatergic dysfunction is a common neuropathological pathway in both substance use and depression. Therefore, glutamatergic neuromodulation is a rational drug target in this comorbidity.
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Affiliation(s)
- Mark J. Niciu
- Yale University Department of Psychiatry/Connecticut Mental Health Center (CMHC), Clinical Neuroscience Research Unit (CNRU), New Haven, CT, USA,Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Ioline D. Henter
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD USA
| | - Gerard Sanacora
- Yale University Department of Psychiatry/Connecticut Mental Health Center (CMHC), Clinical Neuroscience Research Unit (CNRU), New Haven, CT, USA
| | - Carlos A. Zarate
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
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169
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Browne CA, Lucki I. Antidepressant effects of ketamine: mechanisms underlying fast-acting novel antidepressants. Front Pharmacol 2013; 4:161. [PMID: 24409146 PMCID: PMC3873522 DOI: 10.3389/fphar.2013.00161] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/07/2013] [Indexed: 01/21/2023] Open
Abstract
Newer antidepressants are needed for the many individuals with major depressive disorder (MDD) that do not respond adequately to treatment and because of a delay of weeks before the emergence of therapeutic effects. Recent evidence from clinical trials shows that the NMDA antagonist ketamine is a revolutionary novel antidepressant because it acts rapidly and is effective for treatment-resistant patients. A single infusion of ketamine alleviates depressive symptoms in treatment-resistant depressed patients within hours and these effects may be sustained for up to 2 weeks. Although the discovery of ketamine's effects has reshaped drug discovery for antidepressants, the psychotomimetic properties of this compound limit the use of this therapy to the most severely ill patients. In order to develop additional antidepressants like ketamine, adequate preclinical behavioral screening paradigms for fast-acting antidepressants need to be established and used to identify the underlying neural mechanisms. This review examines the preclinical literature attempting to model the antidepressant-like effects of ketamine. Acute administration of ketamine has produced effects in behavioral screens for antidepressants like the forced swim test, novelty suppression of feeding and in rodent models for depression. Protracted behavioral effects of ketamine have been reported to appear after a single treatment that last for days. This temporal pattern is similar to its clinical effects and may serve as a new animal paradigm for rapid antidepressant effects in humans. In addition, protracted changes in molecules mediating synaptic plasticity have been implicated in mediating the antidepressant-like behavioral effects of ketamine. Current preclinical studies are examining compounds with more specific pharmacological effects at glutamate receptors and synapses in order to develop additional rapidly acting antidepressants without the hallucinogenic side effects or abuse potential of ketamine.
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Affiliation(s)
- Caroline A Browne
- Department of Psychiatry, University of Pennsylvania Philadelphia, PA, USA
| | - Irwin Lucki
- Department of Psychiatry, University of Pennsylvania Philadelphia, PA, USA ; Department of Pharmacology, University of Pennsylvania Philadelphia, PA, USA
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170
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Niciu MJ, Ionescu DF, Richards EM, Zarate CA. Glutamate and its receptors in the pathophysiology and treatment of major depressive disorder. J Neural Transm (Vienna) 2013; 121:907-24. [PMID: 24318540 DOI: 10.1007/s00702-013-1130-x] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 11/25/2013] [Indexed: 12/13/2022]
Abstract
Monoaminergic neurotransmitter (serotonin, norepinephrine and dopamine) mechanisms of disease dominated the research landscape in the pathophysiology and treatment of major depressive disorder (MDD) for more than 50 years and still dominate available treatment options. However, the sum of all brain neurons that use monoamines as their primary neurotransmitter is <20%. In addition, most patients treated with monoaminergic antidepressants are left with significant residual symptoms and psychosocial disability not to mention side effects, e.g., sexual dysfunction. In the past several decades, there has been greater focus on the major excitatory neurotransmitter in the human brain, glutamate, in the pathophysiology and treatment of MDD. Although several preclinical and human magnetic resonance spectroscopy studies had already implicated glutamatergic abnormalities in the human brain, it was rocketed by the discovery that the N-methyl-D-aspartate receptor antagonist ketamine has rapid and potent antidepressant effects in even the most treatment-resistant MDD patients, including those who failed to respond to electroconvulsive therapy and who have active suicidal ideation. In this review, we will first provide a brief introduction to glutamate and its receptors in the mammalian brain. We will then review the clinical evidence for glutamatergic dysfunction in MDD, the discovery and progress-to-date with ketamine as a rapidly acting antidepressant, and other glutamate receptor modulators (including proprietary medications) for treatment-resistant depression. We will finally conclude by offering potential future directions necessary to realize the enormous therapeutic promise of glutamatergic antidepressants.
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Affiliation(s)
- Mark J Niciu
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Building 10/CRC, Room 7-5545, Bethesda, MD, 20892, USA,
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Hayley S, Litteljohn D. Neuroplasticity and the next wave of antidepressant strategies. Front Cell Neurosci 2013; 7:218. [PMID: 24312008 PMCID: PMC3834236 DOI: 10.3389/fncel.2013.00218] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 10/29/2013] [Indexed: 12/13/2022] Open
Abstract
Depression is a common chronic psychiatric disorder that is also often co-morbid with numerous neurological and immune diseases. Accumulating evidence indicates that disturbances of neuroplasticity occur with depression, including reductions of hippocampal neurogenesis and cortical synaptogenesis. Improper trophic support stemming from stressor-induced reductions of growth factors, most notably brain derived neurotrophic factor (BDNF), likely drives such aberrant neuroplasticity. We posit that psychological and immune stressors can interact upon a vulnerable genetic background to promote depression by disturbing BDNF and neuroplastic processes. Furthermore, the chronic and commonly relapsing nature of depression is suggested to stem from "faulty wiring" of emotional circuits driven by neuroplastic aberrations. The present review considers depression in such terms and attempts to integrate the available evidence indicating that the efficacy of current and "next wave" antidepressant treatments, whether used alone or in combination, is at least partially tied to their ability to modulate neuroplasticity. We particularly focus on the N-methyl-D-aspartate (NMDA) antagonist, ketamine, which already has well documented rapid antidepressant effects, and the trophic cytokine, erythropoietin (EPO), which we propose as a potential adjunctive antidepressant agent.
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Affiliation(s)
- Shawn Hayley
- Department of Neuroscience, Carleton University Ottawa, ON, Canada
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172
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Moskal JR, Burch R, Burgdorf JS, Kroes RA, Stanton PK, Disterhoft JF, Leander JD. GLYX-13, an NMDA receptor glycine site functional partial agonist enhances cognition and produces antidepressant effects without the psychotomimetic side effects of NMDA receptor antagonists. Expert Opin Investig Drugs 2013; 23:243-54. [PMID: 24251380 DOI: 10.1517/13543784.2014.852536] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The N-methyl-d-aspartate receptor-ionophore complex plays a key role in learning and memory and has efficacy in animals and humans with affective disorders. GLYX-13 is an N-methyl-d-aspartate receptor (NMDAR) glycine-site functional partial agonist and cognitive enhancer that also shows rapid antidepressant activity without psychotomimetic side effects. AREAS COVERED The authors review the mechanism of action of GLYX-13 that was investigated in preclinical studies and evaluated in clinical studies. Specifically, the authors review its pharmacology, pharmacokinetics, and drug safety that were demonstrated in clinical studies. EXPERT OPINION NMDAR full antagonists can produce rapid antidepressant effects in treatment-resistant subjects; however, they are often accompanied by psychotomimetic effects that make chronic use outside of a clinical trial inpatient setting problematic. GLYX-13 appears to exert its antidepressant effects in the frontal cortex via NMDAR-triggered synaptic plasticity. Understanding the mechanistic underpinning of GLYX-13's antidepressant action should provide both novel insights into the role of the glutamatergic system in depression and identify new targets for therapeutic development.
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Affiliation(s)
- Joseph R Moskal
- Northwestern University, McCormick School of Engineering and Applied Science, Falk Center for Molecular Therapeutics, Department of Biomedical Engineering , 1801 Maple Avenue, Suite 4300, Evanston IL 60201 , USA
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173
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Atigari O, Healy D. Pro-convulsant effects: a neglected dimension of psychotropic activity. Aust N Z J Psychiatry 2013; 47:998-1001. [PMID: 23798716 DOI: 10.1177/0004867413495469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Onome Atigari
- Department of Psychological Medicine, Ysbyty Gwynedd Hospital, Wales
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174
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Randomized controlled crossover trial of ketamine in obsessive-compulsive disorder: proof-of-concept. Neuropsychopharmacology 2013; 38:2475-83. [PMID: 23783065 PMCID: PMC3799067 DOI: 10.1038/npp.2013.150] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 06/08/2013] [Accepted: 06/10/2013] [Indexed: 12/18/2022]
Abstract
Serotonin reuptake inhibitors (SRIs), the first-line pharmacological treatment for obsessive-compulsive disorder (OCD), have two limitations: incomplete symptom relief and 2-3 months lag time before clinically meaningful improvement. New medications with faster onset are needed. As converging evidence suggests a role for the glutamate system in the pathophysiology of OCD, we tested whether a single dose of ketamine, a non-competitive N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, could achieve rapid anti-obsessional effects. In a randomized, double-blind, placebo-controlled, crossover design, drug-free OCD adults (n=15) with near-constant obsessions received two 40-min intravenous infusions, one of saline and one of ketamine (0.5 mg/kg), spaced at least 1-week apart. The OCD visual analog scale (OCD-VAS) and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) were used to assess OCD symptoms. Unexpectedly, ketamine's effects within the crossover design showed significant (p<0.005) carryover effects (ie, lasting longer than 1 week). As a result, only the first-phase data were used in additional analyses. Specifically, those receiving ketamine (n=8) reported significant improvement in obsessions (measured by OCD-VAS) during the infusion compared with subjects receiving placebo (n=7). One-week post-infusion, 50% of those receiving ketamine (n=8) met criteria for treatment response (≥35% Y-BOCS reduction) vs 0% of those receiving placebo (n=7). Rapid anti-OCD effects from a single intravenous dose of ketamine can persist for at least 1 week in some OCD patients with constant intrusive thoughts. This is the first randomized, controlled trial to demonstrate that a drug affecting glutamate neurotransmission can reduce OCD symptoms without the presence of an SRI and is consistent with a glutamatergic hypothesis of OCD.
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175
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Second messenger/signal transduction pathways in major mood disorders: moving from membrane to mechanism of action, part I: major depressive disorder. CNS Spectr 2013; 18:231-41. [PMID: 23462230 PMCID: PMC4955397 DOI: 10.1017/s1092852913000059] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The etiopathogenesis and treatment of major mood disorders have historically focused on modulation of monoaminergic (serotonin, norepinephrine, dopamine) and amino acid [γ-aminobutyric acid (GABA), glutamate] receptors at the plasma membrane. Although the activation and inhibition of these receptors acutely alter local neurotransmitter levels, their neuropsychiatric effects are not immediately observed. This time lag implicates intracellular neuroplasticity as primary in the mechanism of action of antidepressants and mood stabilizers. The modulation of intracellular second messenger/signal transduction cascades affects neurotrophic pathways that are both necessary and sufficient for monoaminergic and amino acid-based treatments. In this review, we will discuss the evidence in support of intracellular mediators in the pathophysiology and treatment of preclinical models of despair and major depressive disorder (MDD). More specifically, we will focus on the following pathways: cAMP/PKA/CREB, neurotrophin-mediated (MAPK and others), p11, Wnt/Fz/Dvl/GSK3β, and NFκB/ΔFosB. We will also discuss recent discoveries with rapidly acting antidepressants, which activate the mammalian target of rapamycin (mTOR) and release of inhibition on local translation via elongation factor stimulation. Throughout this discourse, we will highlight potential intracellular targets for therapeutic intervention. Finally, future clinical implications are discussed.
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176
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Abstract
RATIONALE An increasingly compelling literature points to a major role for the glutamate system in mediating the effects of alcohol on behavior and the pathophysiology of alcoholism. Preclinical studies indicate that glutamate signaling mediates certain aspects of ethanol's intoxicating and rewarding effects, and undergoes adaptations following chronic alcohol exposure that may contribute to the withdrawal, craving and compulsive drug-seeking that drive alcohol abuse and alcoholism. OBJECTIVES We discuss the potential for targeting the glutamate system as a novel pharmacotherapeutic approach to treating alcohol use disorders, focusing on five major components of the glutamate system: the N-methyl-D-aspartate (NMDA) receptor and specific NMDA subunits, the glycineB site on the NMDA receptors (NMDAR), L-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid ionotropic (AMPA) and kainate (KAR) receptors, metabotropic receptors (mGluR), and glutamate transporters. RESULTS Chronic alcohol abuse produces a hyperglutamatergic state, characterized by elevated extracellular glutamate and altered glutamate receptors and transporters. Pharmacologically manipulating glutamatergic neurotransmission alters alcohol-related behaviors including intoxication, withdrawal, and alcohol-seeking, in rodents and human subjects. Blocking NMDA and AMPA receptors reduces alcohol consumption in rodents, but side-effects may limit this as a therapeutic approach. Selectively targeting NMDA and AMPA receptor subunits (e.g., GluN2B, GluA3), or the NMDAR glycineB site offers an alternative approach. Blocking mGluR5 potently affects various alcohol-related behaviors in rodents, and mGluR2/3 agonism also suppresses alcohol consumption. Finally, glutamate transporter upregulation may mitigate behavioral and neurotoxic sequelae of excess glutamate caused by alcohol. CONCLUSIONS Despite the many challenges that remain, targeting the glutamate system offers genuine promise for developing new treatments for alcoholism.
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177
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Abstract
Case series outlining the treatment of three patients with ketamine, in which two of the patients had a sustained antidepressant effect to ketamine without the need for maintenance on antidepressants. These two responders have an established diagnosis of bipolar affective disorder with a history of response to electroconvulsive therapy and lithium, both of which have an influence on the seizure threshold as has ketamine. The mechanism of action of ketamine is yet unclear and although the current focus is on the N-methyl-d-aspartate and alpha-amino-3-4-hydroxy-5methyl-4-isoxazoleproprionic acid receptors, we additionally recommend that its impact on the seizure threshold should be explored with a view to fully elucidating the mechanism of action.
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Affiliation(s)
- Onome Victor Atigari
- Department of Psychiatry (Hergest Unit), Ysbyty Gwynedd Hospital, Bangor, Wales, UK
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178
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Exploiting N-methyl-d-aspartate channel blockade for a rapid antidepressant response in major depressive disorder. Biol Psychiatry 2013; 74:238-9. [PMID: 23885752 DOI: 10.1016/j.biopsych.2013.05.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 11/22/2022]
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179
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Martinowich K, Jimenez DV, Zarate CA, Manji HK. Rapid antidepressant effects: moving right along. Mol Psychiatry 2013; 18:856-63. [PMID: 23689537 PMCID: PMC3790255 DOI: 10.1038/mp.2013.55] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/25/2013] [Accepted: 03/18/2013] [Indexed: 02/07/2023]
Abstract
Available treatments for depression have significant limitations, including low response rates and substantial lag times for response. Reports of rapid antidepressant effects of a number of compounds, including the glutamate N-methyl-D-aspartate receptor antagonist ketamine, have spurred renewed translational neuroscience efforts aimed at elucidating the molecular and cellular mechanisms of action that result in rapid therapeutic response. This perspective provides an overview of recent advances utilizing compounds with rapid-acting antidepressant effects, discusses potential mechanism of action and provides a framework for future research directions aimed at developing safe, efficacious antidepressants that achieve satisfactory remission not only by working rapidly but also by providing a sustained response.
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Affiliation(s)
- K Martinowich
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD, USA,Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - DV Jimenez
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD, USA
| | - CA Zarate
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - HK Manji
- Global Therapeutic Area Head, Neuroscience, Janssen Research and Development, Titusville, NJ, USA
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180
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Hashimoto K, Malchow B, Falkai P, Schmitt A. Glutamate modulators as potential therapeutic drugs in schizophrenia and affective disorders. Eur Arch Psychiatry Clin Neurosci 2013; 263:367-77. [PMID: 23455590 DOI: 10.1007/s00406-013-0399-y] [Citation(s) in RCA: 165] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 02/19/2013] [Indexed: 12/25/2022]
Abstract
Severe psychiatric disorders such as schizophrenia are related to cognitive and negative symptoms, which often are resistant to current treatment approaches. The glutamatergic system has been implicated in the pathophysiology of schizophrenia and affective disorders. A key component is the dysfunction of the glutamatergic N-methyl-D-aspartate (NMDA) receptor. Substances regulating activation/inhibition of the NMDA receptor have been investigated in schizophrenia and major depression and are promising in therapeutic approaches of negative symptoms, cognition, and mood. In schizophrenia, add-on treatments with glycine, D-serine, D-alanine, D-cycloserine, D-amino acid oxidase inhibitors, glycine transporter-1 (GlyT-1) inhibitors (e.g., sarcosine, bitopertin) and agonists (e.g., LY2140023) or positive allosteric modulator (e.g., ADX71149) of group II metabotropic glutamate receptors (mGluRs) have been studied. In major depression, the NMDA receptor antagonists (e.g., ketamine, AZD6765), GluN2B subtype antagonists (e.g., traxoprodil, MK-0657), and partial agonists (e.g., D-cycloserine, GLYX-13) at the glycine site of the NMDA receptor have been proven to be effective in animal studies and first clinical trials. In addition, clinical studies of mGluR2/3 antagonist BCI-838 (a prodrug of BCI-632 (MGS0039)), mGluR2/3-negative allosteric modulators (NMAs) (e.g., RO499819, RO4432717), and mGluR5 NAMs (e.g., AZD2066, RO4917523) are in progress. Future investigations should include effects on brain structure and activation to elucidate neural mechanisms underlying efficacy of these drugs.
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Affiliation(s)
- Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chiba, 260-8670, Japan.
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181
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Krystal JH, Sanacora G, Duman RS. Rapid-acting glutamatergic antidepressants: the path to ketamine and beyond. Biol Psychiatry 2013; 73:1133-41. [PMID: 23726151 PMCID: PMC3671489 DOI: 10.1016/j.biopsych.2013.03.026] [Citation(s) in RCA: 295] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 03/18/2013] [Accepted: 03/20/2013] [Indexed: 12/31/2022]
Abstract
Traditional antidepressants require many weeks to reveal their therapeutic effects. However, the widely replicated observation that a single subanesthetic dose of the N-methyl-D-aspartate glutamate receptor antagonist ketamine produced meaningful clinical improvement within hours, suggested that rapid-acting antidepressants might be possible. The ketamine studies stimulated a new generation of basic antidepressant research that identified new neural signaling mechanisms in antidepressant response and provided a conceptual framework linking a group of novel antidepressant mechanisms. This article presents the path that led to the testing of ketamine, considers its promise as an antidepressant, and reviews novel treatment mechanisms that are emerging from this line of research.
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Affiliation(s)
- John H. Krystal
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, Clinical Neuroscience Division, VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT,for correspondence: Department of Psychiatry, Yale University School of Medicine, Suite #901, 300 George St, New Haven, CT 06511; , tel: 203-785-6396, fax: 203-785-6196
| | - Gerard Sanacora
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT
| | - Ronald S. Duman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, Clinical Neuroscience Division, VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT
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182
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Pilc A, Wierońska JM, Skolnick P. Glutamate-based antidepressants: preclinical psychopharmacology. Biol Psychiatry 2013; 73:1125-32. [PMID: 23453290 DOI: 10.1016/j.biopsych.2013.01.021] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 01/17/2013] [Accepted: 01/17/2013] [Indexed: 01/19/2023]
Abstract
Over the past 20 years, converging lines of evidence have both linked glutamatergic dysfunction to the pathophysiology of depression and demonstrated that the glutamatergic synapse presents multiple targets for developing novel antidepressants. The robust antidepressant effects of the N-methyl-D-aspartate receptor antagonists ketamine and traxoprodil provide target validation for this family of ionotropic glutamate receptors. This article reviews the preclinical evidence that it may be possible to develop glutamate-based antidepressants by not only modulating ionotropic (N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid) and metabotropic glutamate (mGlu) receptors, including mGlu2/3, mGLu5 and mGlu7 receptors, but also by altering synaptic concentrations of glutamate via specialized transporters such as glial glutamate transporter 1 (excitatory amino-acid transporter 2).
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Affiliation(s)
- Andrzej Pilc
- Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
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183
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Affiliation(s)
- Daniel C. Mathews
- Experimental Therapeutics & Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, and Department of Health and Human Services, Bethesda, Maryland
| | - Carlos A. Zarate
- Experimental Therapeutics & Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, and Department of Health and Human Services, Bethesda, Maryland
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184
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O'Leary OF, Cryan JF. Towards translational rodent models of depression. Cell Tissue Res 2013; 354:141-53. [PMID: 23525777 DOI: 10.1007/s00441-013-1587-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 02/11/2013] [Indexed: 02/02/2023]
Abstract
Rodent models of depression have been developed in an effort to identify novel antidepressant compounds and to further our understanding of the pathophysiology of depression. Various rodent models of depression and antidepressant-like behaviour are currently used but, clearly, none of these current models fully recapitulate all features of depression. Moreover, these models have not resulted in the development of novel non-monoaminergic-based antidepressants with clinical efficacy. Thus, a refinement of the current models of depression is required. The present review outlines the most commonly used models of depression and antidepressant drug-like activity and suggests several factors that should be considered when refining these models.
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Affiliation(s)
- Olivia F O'Leary
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland,
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185
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Abstract
Mood disorders are common and debilitating, resulting in a significant public health burden. Current treatments are only partly effective and patients who have failed to respond to trials of existing antidepressant agents (eg, those who suffer from treatment-resistant depression [TRD]) require innovative therapeutics with novel mechanisms of action. Although neuroscience research has elucidated important aspects of the basic mechanisms of antidepressant action, most antidepressant drugs target monoaminergic mechanisms identified decades ago. Glutamate, the major excitatory neurotransmitter in the central nervous system, and glutamatergic dysfunction has been implicated in mood disorders. These data provide a rationale for the pursuit of glutamatergic agents as novel therapeutic agents. Here, we review preclinical and clinical investigations of glutamatergic agents in mood disorders with a focus on depression. We begin with discussion of evidence for the rapid antidepressant effects of ketamine, followed by studies of the antidepressant efficacy of the currently marketed drugs riluzole and lamotrigine. Promising novel agents currently in development, including N-methyl-D-aspartate (NMDA) receptor modulators, 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl) propanoic acid (AMPA) receptor modulators, and drugs with activity at the metabotropic glutamate (mGlu) receptors are then reviewed. Taken together, both preclinical and clinical evidence exists to support the pursuit of small molecule modulators of the glutamate system as novel therapeutic agents in mood disorders. It is hoped that by targeting neural systems outside of the monoamine system, more effective and perhaps faster acting therapeutics can be developed for patients suffering from these disabling disorders.
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Affiliation(s)
- Kyle Ab Lapidus
- Mood and Anxiety Disorders Program, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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