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Ketamine

NMDA Receptor Antagonists for Treatment of Depression

April 3, 2013 / Depression, Ketamine, Papers, Psychiatry, Psychology, Psychopharmacology, Publications / By / ,

Abstract

Depression is a psychiatric disorder that affects millions of people worldwide. Individuals battling this disorder commonly experience high rates of relapse, persistent residual symptoms, functional impairment, and diminished well-being. Medications have important utility in stabilizing moods and daily functions of many individuals. However, only one third of patients had considerable improvement with a standard antidepressant after 2 months and all patients had to deal with numerous side effects. The N-methyl-d-aspartate (NMDA) receptor family has received special attention because of its critical role in psychiatric disorders. Direct targeting of the NMDA receptor could result in more rapid antidepressant effects. Antidepressant-like effects of NMDA receptor antagonists have been demonstrated in different animal models. MK-801 (a use-dependent channel blocker), and CGP 37849 (an NMDA receptor antagonist) have shown antidepressant properties in preclinical studies, either alone or combined with traditional antidepressants. A recent development is use of ketamine clinically for refractory depression. The purpose of this review is to examine and analyze current literature on the role of NMDA receptor antagonists for treatment of depression and whether this is a feasible route in drug discovery.

Ates-Alagoz, Z., & Adejare, A. (2013). NMDA Receptor Antagonists for Treatment of Depression. Pharmaceuticals, 6(4), 480-499. http://dx.doi.org/10.3390/ph6040480
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The Ketamine Analogue Methoxetamine and 3- and 4-Methoxy Analogues of Phencyclidine Are High Affinity and Selective Ligands for the Glutamate NMDA Receptor

March 19, 2013 / Ketamine, Neuroscience, New substances, Other substances, Papers, Psychopharmacology, Publications / By / , , , , , ,

Abstract

In this paper we determined the pharmacological profiles of novel ketamine and phencyclidine analogues currently used as ‘designer drugs’ and compared them to the parent substances via the resources of the National Institute of Mental Health Psychoactive Drug Screening Program. The ketamine analogues methoxetamine ((RS)–2-(ethylamino)-2-(3-methoxyphenyl)cyclohexanone) and 3-MeO-PCE (N-ethyl-1-(3-methoxyphenyl)cyclohexanamine) and the 3- and 4-methoxy analogues of phencyclidine, (1-[1-(3-methoxyphenyl)cyclohexyl]piperidine and 1-[1-(4-methoxyphenyl)cyclohexyl]piperidine), were all high affinity ligands for the PCP-site on the glutamate NMDA receptor. In addition methoxetamine and PCP and its analogues displayed appreciable affinities for the serotonin transporter, whilst the PCP analogues exhibited high affinities for sigma receptors. Antagonism of the NMDA receptor is thought to be the key pharmacological feature underlying the actions of dissociative anaesthetics. The novel ketamine and PCP analogues had significant affinities for the NMDA receptor in radioligand binding assays, which may explain their psychotomimetic effects in human users. Additional actions on other targets could be important for delineating side-effects.

Roth, B. L., Gibbons, S., Arunotayanun, W., Huang, X. P., Setola, V., Treble, R., & Iversen, L. (2013). The ketamine analogue methoxetamine and 3-and 4-methoxy analogues of phencyclidine are high affinity and selective ligands for the glutamate NMDA receptor. PLoS One, 8(3), e59334. http://dx.doi.org/10.1371%2Fjournal.pone.0059334
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Hallucinogen persisting perception disorder: what do we know after 50 years?

March 1, 2013 / Cacti / Mescaline, DMT, HPPD, Ketamine, LSD, MDMA, Mushrooms / Psilocybin, Neuroscience, Other substances, Papers, Psychiatry, Psychology, Psychopharmacology, Publications, Salvia / Salvinorin A / By / ,

Abstract

‘Flashbacks’ following use of hallucinogenic drugs have been reported for decades; they are recognized in DSM-IV as ‘Hallucinogen Persisting Perception Disorder (Flashbacks)’, or HPPD. We located and analyzed 20 quantitative studies between 1955 and 2001 examining this phenomenon. However, many of these studies were performed before operational criteria for HPPD were published in DSM-III-R, so they are difficult to interpret in the light of current diagnostic criteria. Overall, current knowledge of HPPD remains very limited. In particular (1) the term ‘flashbacks’ is defined in so many ways that it is essentially valueless; (2) most studies provide too little information to judge how many cases could meet DSM-IV criteria for HPPD; and consequently (3) information about risk factors for HPPD, possible etiologic mechanisms, and potential treatment modalities must be interpreted with great caution. At present, HPPD appears to be a genuine but uncommon disorder, sometimes persisting for months or years after hallucinogen use and causing substantial morbidity. It is reported most commonly after illicit LSD use, but less commonly with LSD administered in research or treatment settings, or with use of other types of hallucinogens. There are case reports, but no randomized controlled trials, of successful treatment with neuroleptics, anticonvulsants, benzodiazepines, and clonidine. Although it may be difficult to collect large samples of HPPD cases, further studies are critically needed to augment the meager data presently available regarding the prevalence, etiology, and treatment of HPPD.

Halpern, J. H., & Harrison, G. P. Jr. (2003). Hallucinogen persisting perception disorder: what do we know after 50 years? Drug and Alcohol Dependence, 69(2), 109-119. http://dx.doi.org/10.1016/S0376-8716(02)00306-X
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The NMDA antagonist ketamine and the 5-HT agonist psilocybin produce dissociable effects on structural encoding of emotional face expressions

July 27, 2012 / Anxiety disorders / PTSD, Depression, Ketamine, Mushrooms / Psilocybin, Neuroscience, Other subjects, Papers, Psychology, Publications / By / , , , ,

Abstract

Rationale
Both glutamate and serotonin (5-HT) play a key role in the pathophysiology of emotional biases. Recent studies indicate that the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist ketamine and the 5-HT receptor agonist psilocybin are implicated in emotion processing. However, as yet, no study has systematically compared their contribution to emotional biases.

Objectives
This study used event-related potentials (ERPs) and signal detection theory to compare the effects of the NMDA (via S-ketamine) and 5-HT (via psilocybin) receptor system on non-conscious or conscious emotional face processing biases.

Methods
S-ketamine or psilocybin was administrated to two groups of healthy subjects in a double-blind within-subject placebo-controlled design. We behaviorally assessed objective thresholds for non-conscious discrimination in all drug conditions. Electrophysiological responses to fearful, happy, and neutral faces were subsequently recorded with the face-specific P100 and N170 ERP.

Results
Both S-ketamine and psilocybin impaired the encoding of fearful faces as expressed by a reduced N170 over parieto-occipital brain regions. In contrast, while S-ketamine also impaired the encoding of happy facial expressions, psilocybin had no effect on the N170 in response to happy faces.

Conclusion
This study demonstrates that the NMDA and 5-HT receptor systems differentially contribute to the structural encoding of emotional face expressions as expressed by the N170. These findings suggest that the assessment of early visual evoked responses might allow detecting pharmacologically induced changes in emotional processing biases and thus provides a framework to study the pathophysiology of dysfunctional emotional biases.

Schmidt, A., Kometer, M., Bachmann, R., Seifritz, E., & Vollenweider, F.X. (2012). The NMDA antagonist ketamine and the 5-HT agonist psilocybin produce dissociable effects on structural encoding of emotional face expressions. Psychopharmacology, 225(1), 227-239. http://dx.doi.org/doi:10.1007/s00213-012-2811-0
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Quantitative Analysis of Narrative Reports of Psychedelic Drugs

June 1, 2012 / Ayahuasca, Cacti / Mescaline, DMT, Iboga / Ibogaine, Ketamine, LSD, MDMA, Mushrooms / Psilocybin, Other disciplines, Other subjects, Other substances, Papers, Publications, Salvia / Salvinorin A / By / , ,

Abstract

Background

Psychedelic drugs facilitate profound changes in consciousness and have potential to provide insights into the nature of human mental processes and their relation to brain physiology. Yet published scientific literature reflects a very limited understanding of the effects of these drugs, especially for newer synthetic compounds. The number of clinical trials and range of drugs formally studied is dwarfed by the number of written descriptions of the many drugs taken by people. Analysis of these descriptions using machine-learning techniques can provide a framework for learning about these drug use experiences.

Methods

We collected 1000 reports of 10 drugs from the drug information website Erowid.org and formed a term-document frequency matrix. Using variable selection and a random-forest classifier, we identified a subset of words that differentiated between drugs.

Results

A random forest using a subset of 110 predictor variables classified with accuracy comparable to a random forest using the full set of 3934 predictors. Our estimated accuracy was 51.1%, which compares favorably to the 10% expected from chance. Reports of MDMA had the highest accuracy at 86.9%; those describing DPT had the lowest at 20.1%. Hierarchical clustering suggested similarities between certain drugs, such as DMT and Salvia divinorum.

Conclusion

Machine-learning techniques can reveal consistencies in descriptions of drug use experiences that vary by drug class. This may be useful for developing hypotheses about the pharmacology and toxicity of new and poorly characterized drugs.

Coyle, J. R., Presti, D. E., Baggott, M. J. (2012). Quantitative Analysis of Narrative Reports of Psychedelic Drugs.
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Replication of Ketamine's Antidepressant Efficacy in Bipolar Depression: A Randomized Controlled Add-On Trial

January 31, 2012 / Depression, Ketamine, Papers, Psychiatry, Psychology, Psychopharmacology, Publications / By / , , , , , ,

Abstract

Background

Currently, no pharmacological treatments for bipolar depression exist that exert rapid (within hours) antidepressant or antisuicidal effects. We previously reported that intravenous administration of the N-methyl-D-aspartate antagonist ketamine produced rapid antidepressant effects in patients with treatment-resistant bipolar depression. The present study sought to replicate this finding in an independent sample.

Methods

In this double-blind, randomized, crossover, placebo-controlled study, 15 subjects with DSM-IV bipolar I or II depression maintained on therapeutic levels of lithium or valproate received a single intravenous infusion of either ketamine hydrochloride (.5 mg/kg) or placebo on 2 test days 2 weeks apart. The primary outcome measure was the Montgomery-Asberg Depression Rating Scale, which was used to rate overall depressive symptoms at baseline; at 40, 80, 110, and 230 minutes postinfusion; and on days 1, 2, 3, 7, 10, and 14 postinfusion.

Results

Within 40 minutes, depressive symptoms, as well as suicidal ideation, significantly improved in subjects receiving ketamine compared with placebo (d = .89, 95% confidence interval = .61–1.16, and .98, 95% confidence interval = .64–1.33, respectively); this improvement remained significant through day 3. Seventy-nine percent of subjects responded to ketamine and 0% responded to placebo at some point during the trial. The most common side effect was dissociative symptoms, which occurred only at the 40-minute time point.

Conclusion

This study replicated our previous finding that patients with bipolar depression who received a single ketamine infusion experienced a rapid and robust antidepressant response. In addition, we found that ketamine rapidly improved suicidal ideation in these patients.

Zarate Jr., A., Brutsche, N. E., Ibrahim, L., Franco-Chaves, J., Diazgranados, N., Cravchik, A., … Luckenbaugh, D. A. (2011). Replication of Ketamine’s Antidepressant Efficacy in Bipolar Depression: A Randomized Controlled Add-On Trial. Biological Psychiatry, 71(11), 939-946. http://dx.doi.org/10.1016/j.biopsych.2011.12.010
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Single versus repeated sessions of ketamine-assisted psychotherapy for people with heroin dependence

September 8, 2011 / Addiction, Ketamine, Papers, Psychiatry, Psychology, Psychopharmacology, Publications / By / , , , , ,

Abstract

A prior study found that one ketamine-assisted psychotherapy session was significantly more effective than active placebo in promoting abstinence (Krupitsky et al. 2002). In this study of the efficacy of single versus repeated sessions of ketamine-assisted psychotherapy in promoting abstinence in people with heroin dependence, 59 detoxified inpatients with heroin dependence received a ketamine-assisted psychotherapy (KPT) session prior to their discharge from an addiction treatment hospital, and were then randomized into two treatment groups. Participants in the first group received two addiction counseling sessions followed by two KPT sessions, with sessions scheduled on a monthly interval (multiple KPT group). Participants in the second group received two addiction counseling sessions on a monthly interval, but no additional ketamine therapy sessions (single KPT group). At one-year follow-up, survival analysis demonstrated a significantly higher rate of abstinence in the multiple KPT group. Thirteen out of 26 subjects (50%) in the multiple KPT group remained abstinent, compared to 6 out of 27 subjects (22.2%) in the single KPT group (p < 0.05). No differences between groups were found in depression, anxiety, craving for heroin, or their understanding of the meaning of their lives. It was concluded that three sessions of ketamine-assisted psychotherapy are more effective than a single session for the treatment of heroin addiction.

Krupitsky, E. M., Burakov, A. M., Dunaevsky, I. V., Romanova, T. N., Slavina, T. Y., & Grinenko, A. Y. (2007). Single versus repeated sessions of ketamine-assisted psychotherapy for people with heroin dependence. Journal of psychoactive drugs, 39(1), 13-19. https://dx.doi.org/10.1080/02791072.2007.10399860
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A preliminary naturalistic study of low-dose ketamine for depression and suicide ideation in the emergency department

September 1, 2011 / Depression, Ketamine, Papers, Psychiatry, Psychology, Psychopharmacology, Publications / By / ,

Abstract

We examined the preliminary feasibility, tolerability and efficacy of single-dose, intravenous (i.v.) ketamine in depressed emergency department (ED) patients with suicide ideation (SI). Fourteen depressed ED patients with SI received a single i.v. bolus of ketamine (0.2 mg/kg) over 1–2 min. Patients were monitored for 4 h, then re-contacted daily for 10 d. Treatment response and time to remission were evaluated using the Montgomery–Asberg Depression Rating Scale (MADRS) and Kaplan–Meier survival analysis, respectively. Mean MADRS scores fell significantly from 40.4 (S.E.M.=1.8) at baseline to 11.5 (S.E.M.=2.2) at 240 min. Median time to MADRS score f10 was 80 min (interquartile range 0.67–24 h). SI scores (MADRS item 10) decreased significantly from 3.9 (S.E.M.=0.4) at baseline to 0.6 (S.E.M.=0.2) after 40 min post-administration ; SI improvements were sustained over 10 d. These data provide preliminary, open-label support for the feasibility and efficacy of ketamine as a rapid-onset antidepressant in the ED.

Larkin, G. L., & Beautrais, A. L. (2011). A preliminary naturalistic study of low-dose ketamine for depression and suicide ideation in the emergency department. International Journal of Neuropsychopharmacology, 1127-1131. http://dx.doi.org/10.1017/S1461145711000629

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Ketamine plus imipramine treatment induces antidepressant-like behavior and increases CREB and BDNF protein levels and PKA and PKC phosphorylation in rat brain

August 1, 2011 / Depression, Ketamine, Papers, Psychiatry, Psychology, Psychopharmacology, Publications / By / , , , , , ,

Abstract

A growing body of evidence has pointed to the N-methyl-d-aspartate (NMDA) receptor antagonists as a potential therapeutic target for the treatment of major depression. The present study investigated the possibility of synergistic interactions between antidepressant imipramine with the uncompetitive NMDA receptor antagonist ketamine. Wistar rats were acutely treated with ketamine (5 and 10 mg/kg) and imipramine (10 and 20 mg/kg) and then subjected to forced swimming tests. The cAMP response element bindig (CREB) and brain-derived neurotrophic factor (BDNF) protein levels and protein kinase C (PKC) and protein kinase A (PKA) phosphorylation were assessed in the prefrontal cortex, hippocampus and amygdala by imunoblot. Imipramine at the dose of 10 mg/kg and ketamine at the dose of 5 mg/kg did not have effect on the immobility time; however, the effect of imipramine (10 and 20 mg/kg) was enhanced by both doses of ketamine. Ketamine and imipramine alone or in combination at all doses tested did not modify locomotor activity. Combined treatment with ketamine and imipramine produced stronger increases of CREB and BDNF protein levels in the prefrontal cortex, hippocampus and amygdala, and PKA phosphorylation in the hippocampus and amygdala and PKC phosphorylation in prefrontal cortex. The results described indicate that co-administration of antidepressant imipramine with ketamine may induce a more pronounced antidepressant activity than treatment with each antidepressant alone. This finding may be of particular importance in the case of drug-resistant patients and could suggest a method of obtaining significant antidepressant actions whilst limiting side effects.

Réus, G. Z., Stringari, R. B., Ribeiro, K. F.,  Ferraro, A. K.,  Vitto, M. F., Cesconetto, P., … Quevedo, J. (2011). Ketamine plus imipramine treatment induces antidepressant-like behavior and increases CREB and BDNF protein levels and PKA and PKC phosphorylation in rat brain. Behavioural Brain Research, 221(1), 166-171. http://dx.doi.org/10.1016/j.bbr.2011.02.024
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Exploring the impact of ketamine on the experience of illusory body ownership

January 1, 2011 / Consciousness, Ketamine, Papers, Psychology, Psychosis, Publications / By / , , , , , ,

Abstract

Background: Our sense of body ownership is profound and familiar, yet it may be misleading. In the rubber-hand illusion, synchronous tactile and visual stimulation lead to the experience that a rubber hand is actually one’s own. This illusion is emer in schizophrenia. Given the evidence that ketamine, a noncompetitive N-methyl-D-aspartate antagonist reproduces symptoms of schizophrenia, we sought to determine whether the rubber-hand illusion is augmented by ketamine.

Methods: We studied 15 healthy volunteers in a within-subjects placebo-controlled study. All volunteers carried out two versions of the rubber-hand task, each under both placebo and ketamine infusions. In one task, they saw a rubber hand being stroked in synchrony with tactile stimulation of their real, hidden hand. In the other, stroking of the real and rubber hands was asynchronous. We recorded subjective changes in sense of ownership, as well as participants’ ability to localize their hidden hand.

Results: Ketamine was associated with significant increases in subjective measures of the illusion and in hand mislocalization. Although asynchronous visuotactile stimulation attenuates the strength of the illusion during both placebo and ketamine, there remained a significant illusory effect during asynchronous visuotactile stimulation under ketamine compared with placebo. The strength of the illusion during asynchronous visuotactile stimulation correlated with other subjective effects of the drug.

Conclusions: Ketamine mimics the perturbed sense of body ownership seen in schizophrenia, suggesting that it produces a comparable alteration in integration of information across sensory domains and in the subjective and behavioral consequences of such integration.

Morgan, H. L., Turner, D. C., Corlett, P. R., Absalom, A. R., Adapa, R., Arana, F. S., … Fletcher, P. C. (2011). Exploring the impact of ketamine on the experience of illusory body ownership. Biological Psychiatry, 69(1), 35-41. http://dx.doi.org/10.1016/j.biopsych.2010.07.032
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30 April - Q&A with Rick Strassman

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