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Ketamine

Ketamine and Phencyclidine: the good, the bad and the unexpected

June 15, 2015 / Humanities & Art, Ketamine, Neuroscience, Papers, Psychology, Publications / By / ,

Abstract

The history of ketamine and phencyclidine from their development as potential clinical anaesthetics, through drugs of abuse and animal models of schizophrenia to potential rapidly acting antidepressants is reviewed. The discovery in 1983 of the NMDA receptor antagonist property of ketamine and phencyclidine was a key step to understanding their pharmacology, including their psychotomimetic effects in man. This review describes the historical context and the course of that discovery and its expansion into other hallucinatory drugs. The relevance of these findings to modern hypotheses of schizophrenia and the implications for drug discovery are reviewed. The finding of the rapidly acting antidepressant effects of ketamine in man are discussed in relation to other glutamatergic mechanisms.

Lodge, D., & Mercier, M. S. (2015). Ketamine and Phencyclidine: the good, the bad and the unexpected. British journal of pharmacology.  https://dx.doi.org/10.1111/bph.13222
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Antidepressant drug action – From rapid changes on network function to network rewiring

June 9, 2015 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / ,

Abstract

There has been significant recent progress in understanding the neurobiological mechanisms of antidepressant treatments. The delayed-onset of action of monoamine-based antidepressant drugs have been linked to their ability to slowly increase synaptic plasticity and neuronal excitability via altering neurotrophic signaling (synthesis of BDNF and activation of its receptor TrkB), dematuration of GABAergic interneurons and inhibition of “breaks of plasticity”. On the other hand, antidepressants rapidly regulate emotional processing that – with the help of heightened plasticity and appropriate rehabilitation – gradually lead to significant changes on functional neuronal connectivity and clinical recovery. Moreover, the discovery of rapid-acting antidepressants, most notably ketamine, has inspired renewed interest for novel antidepressant developments with better efficacy and faster onset of action. Therapeutic effects of rapid-acting antidepressants have been linked with their ability to rapidly regulate neuronal excitability and thereby increase synaptic translation and release of BDNF, activation of the TrkB-mTOR-p70S6k signaling pathway and increased synaptogenesis within the prefrontal cortex. Thus, alterations in TrkB signaling, synaptic plasticity and neuronal excitability are shared neurobiological phenomena implicated in antidepressant responses produced by both gradually and rapid acting antidepressants. However, regardless of antidepressant, their therapeutic effects are not permanent which suggests that their effects on neuronal connectivity and network function remain unstable and vulnerable for psychosocial challenges.

Rantamäki, T., & Yalcin, I. (2015). Antidepressant drug action–from rapid changes on network function to network rewiring. Progress in Neuro-Psychopharmacology and Biological Psychiatry. https://dx.doi.org/10.1016/j.pnpbp.2015.06.001
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In vivo effects of ketamine on glutamate-glutamine and gamma-aminobutyric acid in obsessive-compulsive disorder: Proof of concept

June 6, 2015 / Anxiety Disorders / PTSD, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , , , , ,

Abstract

We previously reported the rapid and robust clinical effects of ketamine versus saline infusions in a proof-of-concept crossover trial in unmedicated adults with obsessive-compulsive disorder (OCD). This study examined the concurrent neurochemical effects of ketamine versus saline infusions using proton magnetic resonance spectroscopy (H MRS) during the clinical proof-of-concept crossover trial. Levels of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and the excitatory neurochemicals glutamate+glutamine (Glx) were acquired in the medial prefrontal cortex (MPFC), a region implicated in OCD pathology. Seventeen unmedicated OCD adults received two intravenous infusions at least 1 week apart, one of saline and one of ketamine, while lying supine in a 3.0 T GE MR scanner. The order of each infusion pair was randomized. Levels of GABA and Glx were measured in the MPFC before, during, and after each infusion and normalized to water (W). A mixed effects model found that MPFC GABA/W significantly increased over time in the ketamine compared with the saline infusion. In contrast, there were no significant differences in Glx/W between the ketamine and saline infusions. Together with earlier evidence of low cortical GABA in OCD, our findings suggest that models of OCD pathology should consider the role of GABAergic abnormalities in OCD symptomatology.

Rodriguez, C. I., Kegeles, L. S., Levinson, A., Ogden, R. T., Mao, X., Milak, M. S., … & Simpson, H. B. (2015). In vivo effects of ketamine on glutamate-glutamine and gamma-aminobutyric acid in obsessive-compulsive disorder: Proof of concept. Psychiatry Research: Neuroimaging. http://dx.doi.org/10.1016/j.pscychresns.2015.06.001
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The use of ketamine for the treatment of depression in the context of psychotic symptoms

June 4, 2015 / Depressive Disorders, Ketamine, Papers, Psychology, Psychotic Disorders, Publications / By / , , ,

Abstract

Mounting evidence from a series of small clinical trials and case series suggests ketamine can have rapid and robust antidepressant(1), and possibly anti-suicidal effects(2) in patients who had not responded to standard treatment options. However, due to ketamine’s variable psychotomimetic effects in healthy volunteers and exacerbation of previously experienced positive symptoms in schizophrenic volunteers(3,4), patients previously experiencing psychotic features have been excluded from the reported studies and trials.

da Frota Ribeiro, C. M., Sanacora, G., Hoffman, R., & Ostroff, R. (2015). The use of ketamine for the treatment of depression in the context of psychotic symptoms. Biological Psychiatry. http://dx.doi.org/10.1016/j.biopsych.2015.05.016
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Single-Dose ketamine followed by daily D-Cycloserine in treatment-resistant bipolar depression

June 1, 2015 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , ,

Abstract

Bipolar depression is a leading cause of disability in the United States. Recently, N-methyl-D-asparate glutamate-receptor (NMDAR) antagonists, such as ketamine, have been shown to induce remission in bipolar depression. Nevertheless, ketamine use is limited by transient effects and psychogenic potential during repeated administration.

Kantrowitz, J. T., Halberstam, B., & Gangwisch, J. (2015). Single-Dose ketamine followed by daily D-Cycloserine in treatment-resistant bipolar depression. The Journal of clinical psychiatry, 76(6), 737-738. https://dx.doi.org/10.4088/JCP.14l09527
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The positive effect on ketamine as a priming adjuvant in antidepressant treatment.

May 26, 2015 / Depressive Disorders, Ketamine, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Ketamine is an anesthetic with antidepressant properties. The rapid and lasting effect of ketamine observed in preclinical and clinical research makes it a promising therapeutic to improve current major depression (MD) treatment. Our work intended to evaluate whether the combined use of classic antidepressants (imipramine or fluoxetine) and ketamine would improve the antidepressant response. Using an animal model of depressive-like behavior, we show that the addition of ketamine to antidepressants anticipates the behavioral response and accelerates the neuroplastic events when compared with the use of antidepressants alone. In conclusion, our results suggest the need for a reappraisal of the current pharmacological treatment of MD.

Melo, A., Kokras, N., Dalla, C., Ferreira, C., Ventura-Silva, A. P., Sousa, N., & Pêgo, J. M. (2015). The positive effect on ketamine as a priming adjuvant in antidepressant treatment. Translational Psychiatry, 5(5), e573. https://dx.doi.org/10.1038/tp.2015.66
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Ketamine induces a robust whole-brain connectivity pattern that can be differentially modulated by drugs of different mechanism and clinical profile

May 19, 2015 / Ketamine, Neuroscience, Papers, Publications / By / , , , , , ,

Abstract

Ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist, has been studied in relation to the glutamate hypothesis of schizophrenia and increases dissociation, positive and negative symptom ratings. Ketamine effects brain function through changes in brain activity; these activity patterns can be modulated by pre-treatment of compounds known to attenuate the effects of ketamine on glutamate release. Ketamine also has marked effects on brain connectivity; we predicted that these changes would also be modulated by compounds known to attenuate glutamate release. Here, we perform task-free pharmacological magnetic resonance imaging (phMRI) to investigate the functional connectivity effects of ketamine in the brain and the potential modulation of these effects by pre-treatment of the compounds lamotrigine and risperidone, compounds hypothesised to differentially modulate glutamate release. Connectivity patterns were assessed by combining windowing, graph theory and multivariate Gaussian process classification. We demonstrate that ketamine has a robust effect on the functional connectivity of the human brain compared to saline (87.5 % accuracy). Ketamine produced a shift from a cortically centred, to a subcortically centred pattern of connections. This effect is strongly modulated by pre-treatment with risperidone (81.25 %) but not lamotrigine (43.75 %). Based on the differential effect of these compounds on ketamine response, we suggest the observed connectivity effects are primarily due to NMDAR blockade rather than downstream glutamatergic effects. The connectivity changes contrast with amplitude of response for which no differential effect between pre-treatments was detected, highlighting the necessity of these techniques in forming an informed view of the mechanistic effects of pharmacological compounds in the human brain.

Joules, R., Doyle, O. M., Schwarz, A. J., O’Daly, O. G., Brammer, M., Williams, S. C., & Mehta, M. A. (2015). Ketamine induces a robust whole-brain connectivity pattern that can be differentially modulated by drugs of different mechanism and clinical profile. Psychopharmacology, 1-14. https://dx.doi.org/10.1007/s00213-015-3951-9

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Immunomodulatory activity of ketamine in human astroglial A172 cells: Possible relevance to its rapid antidepressant activity.

May 15, 2015 / Depressive Disorders, Ketamine, Neuroscience, Papers, Publications / By / , , ,

Abstract

To determine if the immunomodulatory effect of ketamine is relevant to its rapid antidepressant activity, cultured human astroglial cells were incubated with ketamine, cytokine mix, or both. At 24h, ketamine dose-dependently (100-500 μM) decreased IL-6 and TNFα production and gene expression and, at clinically relevant concentration (100 μM), augmented IL-β release and gene expression in both unstimulated and cytokine-stimulated cells. In unstimulated cells, ketamine also increased IL-8 production and mRNA expression. The reduction in IL-6 mRNA was significant within 1h in unstimulated cells and at 4h after stimulation. Ketamine suppressed the production of the only established depression-relevant proinflammatory cytokines, IL-6 and TNFα.

Yuhas, Y., Ashkenazi, S., Berent, E., & Weizman, A. (2015). Immunomodulatory activity of ketamine in human astroglial A172 cells: Possible relevance to its rapid antidepressant activity. Journal of neuroimmunology, 282, 33-38. https://dx.doi.org/10.1016/j.jneuroim.2015.03.012
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Ketamine-induced state models schizophrenia

February 7, 2022 / Ketamine, Psychology, Psychotic Disorders / By

In the 1950’s, research on the psychoactive properties of lysergic acid diethylamide (LSD) led scientists to the serotonin hypothesis of schizophrenia, a theory still used to explain the neurochemical roots of schizophrenia. Today, Höflich et al. (2015) have used ketamine to explore the role of neurotransmitter glutamate in this mental disorder [3].

Since neuroimaging studies indicated dysfunctional glutamate pathways in schizophrenia, glutamate is thought to play a key role in its aetiology. These abnormalities are specifically apparent in the thalamus, a brain region regarded as the information integration system of the brain. By measuring brain activity in healthy volunteers after ketamine administration, Höflich et al. (2015) explored ketamine as a model for schizophrenia to further investigate the link between glutamate and schizophrenia. Ketamine is a glutamate antagonist, which means that it prevents neurotransmission by blocking the activity of glutamate on N-methyl-D-aspartate (NMDA) receptors. The effects of ketamine resemble some of the positive, negative, and cognitive symptoms of schizophrenia.

In the study of Höflich et al. (2015), thirty healthy volunteers completed a double-blind, placebo-controlled, randomized, crossover study in which each volunteer was scanned using fMRI on two separate days. Brain network activation under ketamine was compared to placebo. The brain images revealed higher functional connectivity in the thalamus hub network in the ketamine condition compared to placebo. Furthermore, ketamine induced higher connectivity between thalamic regions and somatosensory and temporal cortices. Connectivity between the thalamus and prefrontal, motor, posterior parietal, and occipital cortices did not differ significantly.

The authors conclude that ketamine temporarily triggers alterations in functional connectivity in healthy volunteers that resemble structural brain connectivity patterns in schizophrenic patients. They infer that the ketamine-induced state might function as a model of schizophrenia, especially relative to characteristic sensory filtering problems. However, their results did not reveal a decrease of prefrontal-thalamic connectivity typical for schizophrenic patients [4] suggesting that other neurotransmitters also account for the manifestation of schizophrenia. Using ketamine and other drug models [5] to investigate the relationship between neurotransmitter systems and the symptomatology of schizophrenia could yield valuable information about the neural underpinnings of this mental disorder.

[1] Gaddum, J. H., Hebb, C. O., Silver, A., & Swan, A. A. B. (1953). 5-Hydroxytryptamine. Pharmacological action and destruction in perfused lungs. Quart. J. Exper. Physiol., 38, 255.
[2] Woolley, D. W., & Shaw, E. (1954). a Biochemical and Pharmacological Suggestion About Certain Mental Disorders. Proceedings of the National Academy of Sciences of the United States of America, 40(4), 228–231. doi:10.1073/pnas.40.4.228
[3] Höflich, A., Hahn, A., Küblböck, M., Kranz, G. S., Vanicek, T., Windischberger, C., …Lanzenberger, R. (2015). Ketamine-Induced Modulation of the Thalamo- Cortical Network in Healthy Volunteers As a Model for Schizophrenia. International Journal of Neuropsychopharmacology, 1–11. doi:10.1093/ijnp/pyv040 [Abstract]
[4] Leitman DI, Sehatpour P, Higgins BA, Foxe JJ, Silipo G, Javitt DC (2010) Sensory deficits and distributed hierarchical dysfunction in schizophrenia. Am J Psychiatry 167:818–827
[5] Steeds, H., Carhart-Harris, R. L., & Stone, J. M. (2014). Drug models of schizophrenia. Therapeutic Advances in Psychopharmacology, 5(1), 43–58. doi:10.1177/2045125314557797 [Abstract][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]

Intranasal drug delivery in neuropsychiatry: focus on intranasal ketamine for refractory depression.

May 1, 2015 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By /

Abstract

Intranasal drug delivery (INDD) systems offer a route to the brain that bypasses problems related to gastrointestinal absorption, first-pass metabolism, and the blood-brain barrier; onset of therapeutic action is rapid, and the inconvenience and discomfort of parenteral administration are avoided. INDD has found several applications in neuropsychiatry, such as to treat migraine, acute and chronic pain, Parkinson disease, disorders of cognition, autism, schizophrenia, social phobia, and depression. INDD has also been used to test experimental drugs, such as peptides, for neuropsychiatric indications; these drugs cannot easily be administered by other routes. This article examines the advantages and applications of INDD in neuropsychiatry; provides examples of test, experimental, and approved INDD treatments; and focuses especially on the potential of intranasal ketamine for the acute and maintenance therapy of refractory depression.

Andrade, C. (2015). Intranasal drug delivery in neuropsychiatry: focus on intranasal ketamine for refractory depression. The Journal of clinical psychiatry, 76(5), e628-31. https://dx.doi.org/10.4088/JCP.15f10026

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