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Comparative potencies of MDMA analogues as inhibitors of [3H]noradrenaline and [3H]5-HT transport in mammalian cell lines

December 1, 2007 / Chemistry, MDMA, New substances, Other subjects, Other substances, Papers, Psychopharmacology, Publications / By / , , , , ,

Abstract

Background and purpose:Illegal ‘ecstasy’ tablets frequently contain 3,4-methylenedioxymethamphetamine (MDMA)-like compounds of unknown pharmacological activity. Since monoamine transporters are one of the primary targets of MDMA action in the brain, a number of MDMA analogues have been tested for their ability to inhibit [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][3H]noradrenaline uptake into rat PC12 cells expressing the noradrenaline transporter (NET) and [3H]5-HT uptake into HEK293 cells stably transfected with the 5-HT transporter (SERT).

Experimental approach:Concentration–response curves for the following compounds at both NET and SERT were determined under saturating substrate conditions: 4-hydroxy-3-methoxyamphetamine (HMA), 4-hydroxy 3-methoxymethamphetamine (HMMA), 3,4-methylenedioxy-N-hydroxyamphetamine (MDOH), 2,5-dimethoxy-4-bromophenylethylamine (2CB), 3,4-dimethoxymethamphetamine (DMMA), 3,4-methylenedioxyphenyl-2-butanamine (BDB), 3,4-methylenedioxyphenyl- N-methyl-2-butanamine (MBDB) and 2,3-methylenedioxymethamphetamine (2,3-MDMA).

Key results: 2,3-MDMA was significantly less potent than MDMA at SERT, but equipotent with MDMA at NET. 2CB and BDB were both significantly less potent than MDMA at NET, but equipotent with MDMA at SERT. MBDB, DMMA, MDOH and the MDMA metabolites HMA and HMMA, were all significantly less potent than MDMA at both NET and SERT.

Conclusions and implications: This study provides an important insight into the structural requirements of MDMA analogue affinity at both NET and SERT. It is anticipated that these results will facilitate understanding of the likely pharmacological actions of structural analogues of MDMA.

Montgomery, T., Buon, C., Eibauer, S., Guiry, P. J., Keenan, A.K., & McBean, G. J. (2007). Comparative potencies of MDMA analogues as inhibitors of [3H]noradrenaline and [3H]5-HT transport in mammalian cell lines. British Journal of Pharmacology, 152(7), 1121–1130. http://dx.doi.org/10.1038/sj.bjp.0707473
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Psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans

September 14, 2007 / Mushrooms / Psilocybin, Neuroscience, Other subjects, Papers, Psychiatry, Psychopharmacology, Publications / By / , , , , ,

Abstract

Rationale: Binocular rivalry occurs when different images are simultaneously presented to each eye. During continual viewing of this stimulus, the observer will experience repeated switches between visual awareness of the two images. Previous studies have suggested that a slow rate of perceptual switching may be associated with clinical and drug-induced psychosis.

Objectives: The objective of the study was to explore the proposed relationship between binocular rivalry switch rate and subjective changes in psychological state associated with 5-HT2A receptor activation.

Materials and methods: This study used psilocybin, the hallucinogen found naturally in Psilocybe mushrooms that had previously been found to induce psychosis-like symptoms via the 5-HT2A receptor. The effects of psilocybin (215 μg/kg) were considered alone and after pretreatment with the selective 5-HT2A antagonist ketanserin (50 mg) in ten healthy human subjects.

Results: Psilocybin significantly reduced the rate of binocular rivalry switching and increased the proportion of transitional/mixed percept experience. Pretreatment with ketanserin blocked the majority of psilocybin’s “positive” psychosis-like hallucinogenic symptoms. However, ketanserin had no influence on either the psilocybin-induced slowing of binocular rivalry or the drug’s “negative-type symptoms” associated with reduced arousal and vigilance.

Conclusions: Together, these findings link changes in binocular rivalry switching rate to subjective levels of arousal and attention. In addition, it suggests that psilocybin’s effect on binocular rivalry is unlikely to be mediated by the 5-HT2A receptor.

Carter, O. L., Hasler, F., Pettigrew, J. D., Wallis, G. M., Liu, G. B., & Vollenweider, F. X. (2007). Psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans. Psychopharmacology, 195(3), 415-424. 10.1007/s00213-007-0930-9

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Psilocybin-induced stimulus control in the rat

June 22, 2007 / Mushrooms / Psilocybin, Neuroscience, Other subjects, Papers, Psychopharmacology, Publications / By / , , ,

Abstract

Although psilocybin has been trained in the rat as a discriminative stimulus, little is known of the pharmacological receptors essential for stimulus control. In the present investigation rats were trained with psilocybin and tests were then conducted employing a series of other hallucinogens and presumed antagonists. An intermediate degree of antagonism of psilocybin was observed following treatment with the 5-HT2A receptor antagonist, M100907. In contrast, no significant antagonism was observed following treatment with the 5-HT1A/7 receptor antagonist, WAY-100635, or the DA D2 antagonist, remoxipride. Psilocybin generalized fully to DOM, LSD, psilocin, and, in the presence of WAY-100635, DMT while partial generalization was seen to 2C-T-7 and mescaline. LSD and MDMA partially generalized to psilocybin and these effects were completely blocked by M-100907; no generalization of PCP to psilocybin was seen. The present data suggest that psilocybin induces a compound stimulus in which activity at the 5-HT2A receptor plays a prominent but incomplete role. In addition, psilocybin differs from closely related hallucinogens such as 5-MeO-DMT in that agonism at 5-HT1A receptors appears to play no role in psilocybin-induced stimulus control.

Winter, J. C., Rice, K. C., Amorosi, D. J., & Rabin, R. A. (2007). Psilocybin-induced stimulus control in the rat. Pharmacology Biochemistry and Behavior, 87(4), 472-480. http://dx.doi.org/10.1016/j.pbb.2007.06.003
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Brave New World versus Island — Utopian and Dystopian Views on Psychopharmacology

May 8, 2007 / Other disciplines, Other subjects, Other substances, Papers, Philosophy, Psychopharmacology, Publications, Sociology / By /

Abstract

Aldous Huxley’s Brave New World is a famous dystopia, frequently called upon in public discussions about new biotechnology. It is less well known that 30 years later Huxley also wrote a utopian novel, called Island. This paper will discuss both novels focussing especially on the role of psychopharmacological substances. If we see fiction as a way of imagining what the world could look like, then what can we learn from Huxley’s novels about psychopharmacology and how does that relate to the discussion in the ethical and philosophical literature on this subject? The paper argues that in the current ethical discussion the dystopian vision on psychopharmacology is dominant, but that a comparison between Brave New World and Island shows that a more utopian view is possible as well. This is illustrated by a discussion of the issue of psychopharmacology and authenticity. The second part of the paper draws some further conclusions for the ethical debate on psychopharmacology and human enhancement, by comparing the novels not only with each other, but also with our present reality. It is claimed that the debate should not get stuck in an opposition of dystopian and utopian views, but should address important issues that demand attention in our real world: those of evaluation and governance of enhancing psychopharmacological substances in democratic, pluralistic societies.

Schermer, M. H. N. (2007). Brave New World versus Island—Utopian and Dystopian Views on Psychopharmacology. Medicine, Health Care and Philosophy, 10(2), 119-128. https://dx.doi.org/10.1007/s11019-007-9059-1

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Safety, tolerability, and efficacy of psilocybin in 9 patients with obsessive-compulsive disorder

November 11, 2006 / Anxiety disorders / PTSD, Mushrooms / Psilocybin, Other subjects, Papers, Psychiatry, Psychology, Psychopharmacology, Psychotherapy, Publications, Safety / By / , , ,

Abstract

Background: Anecdotal reports suggest that psychedelic agents may relieve symptoms of obsessive-compulsive disorder (OCD). This modified double-blind study investigated the safety, tolerability, and clinical effects of psilocybin, a potent 5-HT(1A) and 5-HT(2A/2C) agonist, in patients with OCD.

Method: Nine subjects with DSM-IV-defined OCD and no other current major psychiatric disorder participated in up to 4 single-dose exposures to psilocybin in doses ranging from sub-hallucinogenic to frankly hallucinogenic. Low (100 microg/kg), medium (200 microg/kg), and high (300 microg/kg) doses were assigned in that order, and a very low dose (25 microg/kg) was inserted randomly and in double-blind fashion at any time after the first dose. Testing days were separated by at least 1 week. Each session was conducted over an 8-hour period in a controlled environment in an outpatient clinic; subjects were then transferred to a psychiatric inpatient unit for overnight observation. The Yale-Brown Obsessive Compulsive Scale (YBOCS) and a visual analog scale measuring overall obsessive-compulsive symptom severity were administered at 0, 4, 8, and 24 hours post-ingestion. The Hallucinogen Rating Scale was administered at 8 hours, and vital signs were recorded at 0, 1, 4, 8, and 24 hours after ingestion. The study was conducted from November 2001 to November 2004.

Results: Nine subjects were administered a total of 29 psilocybin doses. One subject experienced transient hypertension without relation to anxiety or somatic symptoms, but no other significant adverse effects were observed. Marked decreases in OCD symptoms of variable degrees were observed in all subjects during 1 or more of the testing sessions (23%-100% decrease in YBOCS score). Repeated-measures analysis of variance for all YBOCS values revealed a significant main effect of time on Wilks lambda (F = 9.86, df = 3,3; p = .046), but no significant effect of dose (F = 2.25, df = 3,3; p = .261) or interaction of time and dose (F = 0.923, df = 9,45; p = .515). Improvement generally lasted past the 24-hour timepoint.

Conclusion: In a controlled clinical environment, psilocybin was safely used in subjects with OCD and was associated with acute reductions in core OCD symptoms in several subjects.
Moreno, F. A., Wiegand, C. B., Taitano, E. K., & Delgado, P. L. (2006). Safety, tolerability, and efficacy of psilocybin in 9 patients with obsessive-compulsive disorder. Journal of Clinical Psychiatry, 67(11), 1735-1740.

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Acute dose of MDMA (75 mg) impairs spatial memory for location but leaves contextual processing of visuospatial information unaffected

March 1, 2006 / MDMA, Other subjects, Papers, Psychiatry, Psychology, Publications / By / ,

Abstract

Rationale: Research concerning spatial memory in 3,4-methylenedioxymethamphetamine (MDMA) users has presented conflicting results showing either the presence or absence of spatial memory deficits. Two factors may have confounded results in abstinent users: memory task characteristics and polydrug use.

Objectives: The present study aims to assess whether a single dose of MDMA affects spatial memory performance during intoxication and withdrawal phase and whether spatial memory performance after MDMA is task dependent.

Materials and methods: Eighteen recreational MDMA users participated in a double-blind, placebo-controlled, three-way crossover design. They were treated with placebo, MDMA 75 mg, and methylphenidate 20 mg. Memory tests were conducted between 1.5 and 2 h (intoxication phase) and between 25.5 and 26 h (withdrawal phase) post-dosing. Two spatial memory tasks of varying complexity were used that required either storage of stimulus location alone (spatial memory task) or memory for location as well as processing of content or contextual information (change blindness task).

Results: After a single dose of MDMA, the subjects made larger localization errors and responded faster compared to placebo in the simple spatial memory task during intoxication phase. Inaccuracy was not due to increased response speed, as determined by regression analysis. Performance in the change blindness task was not affected by MDMA. Methylphenidate did not affect performance on any of the tasks.

Conclusion: It is concluded that a single dose of MDMA impairs spatial memory for location but leaves processing of contextual information intact.

Kuypers, K. P., & Ramaekers, J. G. (2007). Acute dose of MDMA (75 mg) impairs spatial memory for location but leaves contextual processing of visuospatial information unaffected. Psychopharmacology, 189(4), 557-563. 10.1007/s00213-006-0321-7

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Hallucinogenic botanicals of America: A growing need for focused drug education and research

December 22, 2005 / Ayahuasca, Cacti / Mescaline, Ethnobotany, History, Iboga / Ibogaine, Indigenous use, Other disciplines, Other subjects, Other substances, Publications, Safety, Salvia / Salvinorin A, Spirituality / By / ,

Abstract

Botanical sources for medicines in America have been known since long before the arrival of Columbus. Nevertheless, both scientists and the general public are often unaware that some of these botanical drugs are also potent intoxicants. We provide a quick overview of hallucinogenic and dissociative drugs harvested from nature or that are openly and legally cultivated in the United States. Examples of harmful outcomes reported in the media are contrasted with existing responsible ingestion by others, some of whom have the protected right to do so for traditional or sacramental religious purposes. Despite an ongoing and expensive effort to warn people of the potential harms of recreational drug use, little is known about the extent of use of these psychoactive botanicals, and the recent explosion of information available via the Internet could herald a storm of morbidity to come. Mounting more targeted research and educational efforts today may reduce later use and abuse, inform society about the special circumstances of religious use, and better prepare clinicians and other health care providers about the issues involved when people choose to indigenously source psychoactive drugs for human consumption.

Halpern, J. H., & Sewell, R. A. (2005). Hallucinogenic botanicals of America: A growing need for focused drug education and research. Life sciences, 78(5), 519-526. https://dx.doi.org/10.1016/j.lfs.2005.09.005
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Screening the receptorome for plant-based psychoactive compounds

December 22, 2005 / Ayahuasca, Neuroscience, Other subjects, Papers, Psychiatry, Psychology, Psychopharmacology, Publications, Salvia / Salvinorin A / By / ,

Abstract

Throughout time, humans have used psychoactive plants and plant-derived products for spiritual, therapeutic and recreational purposes. Furthermore, the investigation of psychoactive plants such as Cannabis sativa (marijuana), Nicotiana tabacum (tobacco) and analogues of psychoactive plant derivatives such as lysergic acid diethylamide (LSD) have provided insight into our understanding of neurochemical processes and diseases of the CNS. Currently, many of these compounds are being used to treat a variety of diseases, such as depression and anxiety in the case of Piper methysticum Kava Kava (Martin et al., 2002; Singh and Singh, 2002). G-protein coupled receptors (GPCRs) are the most common molecular target for both psychoactive drugs and pharmaceuticals. The “receptorome” (that portion of the genome encoding ligand reception) encompasses more than 8% of the human genome (Roth et al., 2004) and as such provides a large number of possible targets for psychoactive drug interactions. A systematic, comprehensive study is necessary to identify novel active psychoactive plant-based compounds and the molecular targets of known compounds. Herein we describe the development of a high throughput system (HTS) to screen psychoactive compounds against the receptorome and present two examples (Salvia divinorum, the “magic mint” hallucinogen and Banisteriopsis caapi, the main component of Ayahuasca, a psychoactive beverage) where HTS enabled the identification of the molecular target of each compound.

O’connor, K. A., & Roth, B. L. (2005). Screening the receptorome for plant-based psychoactive compounds. Life sciences, 78(5), 506-511. 10.1016/j.lfs.2005.09.002
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Transient memory impairment after acute dose of 75mg 3.4-Methylene-dioxymethamphetamine

November 1, 2005 / MDMA, Other subjects, Papers, Psychiatry, Psychology, Publications / By / ,

Abstract

A range of studies has indicated that users of 3.4-Methylene-dioxymethamphetamine (MDMA, ‘Ecstasy’) display cognitive deficits, particularly memory impairment, as compared to non-drug using controls. Yet it is difficult to determine whether these deficits are caused by MDMA or some other confounding factor, such as polydrug use. The present study was designed to establish the direct relation between MDMA and memory impairment under placebo-controlled conditions. Eighteen recreational MDMA users participated in a double blind, placebo controlled, 3-way crossover design. They were treated with placebo, MDMA 75mg and methylphenidate 20mg. Memory tests were conducted between 1.5-2h (intoxication phase) and between 25.5-26h (withdrawal phase) post dosing. Results showed that a single dose of MDMA caused impairment of immediate and delayed recall on a verbal learning task during the intoxication phase. However, there was no residual memory impairment during the withdrawal phase. Subjects reported more fatigue and less vigour, but no symptoms of depression during the withdrawal phase of MDMA treatment.

Methylphenidate did not affect memory or mood at any time of testing. A single dose of MDMA produces transient memory impairment.

Kuypers, K. P., & Ramaekers, J. G. (2005). Transient memory impairment after acute dose of 75mg 3.4-Methylene-dioxymethamphetamine. Journal of Psychopharmacology, 19(6), 633-639. 10.1177/0269881105056670
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Using Psilocybin to Investigate the Relationship between Attention, Working Memory, and the Serotonin 1A and 2A Receptors

October 1, 2005 / Mushrooms / Psilocybin, Neuroscience, Other subjects, Papers, Psychology, Psychopharmacology, Publications / By / , , , , ,

Abstract

Increasing evidence suggests a link between attention, working memory, serotonin (5-HT), and prefrontal cortex activity. In an attempt to tease out the relationship between these elements, this study tested the effects of the hallucinogenic mixed 5-HT1A/2A receptor agonist psilocybin alone and after pretreatment with the 5-HT2A antagonist ketanserin. Eight healthy human volunteers were tested on a multiple-object tracking task and spatial working memory task under the four conditions: placebo, psilocybin (215 Ag/kg), ketanserin (50 mg), and psilocybin and ketanserin. Psilocybin significantly reduced attentional tracking ability, but had no significant effect on spatial working memory, suggesting a functional dissociation between the two tasks. Pretreatment with ketanserin did not attenuate the effect of psilocybin on attentional performance, suggesting a primary involvement of the 5-HT1A receptor in the observed deficit. Based on physiological and pharmacological data, we speculate that this impaired attentional performance may reflect a reduced ability to suppress or ignore distracting stimuli rather than reduced attentional capacity. The clinical relevance of these results is also discussed.

Carter, O. L., Burr, D. C., Pettigrew, J. D., Wallis, G. M., Hasler, F., & Vollenweider, F. X. (2005). Using psilocybin to investigate the relationship between attention, working memory, and the serotonin 1A and 2A receptors. Journal of Cognitive neuroscience, 17(10), 1497-1508. http://dx.doi.org/10.1162/089892905774597191
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7 May - Psychedelics, Nature & Mental Health with Sam Gandy

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