OPEN Foundation

A. Kalueff

DARK Classics in Chemical Neuroscience: Atropine, Scopolamine, and Other Anticholinergic Deliriant Hallucinogens

Abstract

Anticholinergic drugs based on tropane alkaloids, including atropine, scopolamine, and hyoscyamine, have been used for various medicinal and toxic purposes for millennia. These drugs are competitive antagonists of acetylcholine muscarinic (M-) receptors that potently modulate the central nervous system (CNS). Currently used clinically to treat vomiting, nausea, and bradycardia, as well as alongside other anesthetics to avoid vagal inhibition, these drugs also evoke potent psychotropic effects, including characteristic delirium-like states with hallucinations, altered mood, and cognitive deficits. Given the growing clinical importance of anti-M deliriant hallucinogens, here we discuss their use and abuse, clinical importance, and the growing value in preclinical (experimental) animal models relevant to modeling CNS functions and dysfunctions.

Lakstygal, A., Kolesnikova, T., Khatsko, S., Zabegalov, K., Volgin, A., Demin, K., … & Kalueff, A. (2018). DARK classics in chemical neuroscience: atropine, scopolamine and other anticholinergic deliriant hallucinogens. ACS chemical neuroscience., 10.1021/acschemneuro.8b00615
 
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Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models

Abstract

Hallucinogenic drugs potently alter human behavior and have a millennia-long history of use for medicinal and religious purposes. Interest is rapidly growing in their potential as CNS modulators and therapeutic agents for brain conditions. Antimuscarinic cholinergic drugs, such as atropine and scopolamine, induce characteristic hyperactivity and dream-like hallucinations and form a separate group of hallucinogens known as “deliriants”. Although atropine and scopolamine are relatively well-studied drugs in cholinergic physiology, deliriants represent the least-studied class of hallucinogens in terms of their behavioral and neurological phenotypes. As such, novel approaches and new model organisms are needed to investigate the CNS effects of these compounds. Here, we comprehensively evaluate the preclinical effects of deliriant hallucinogens in various animal models, their mechanisms of action, and potential interplay with other signaling pathways. We also parallel experimental and clinical findings on deliriant agents and outline future directions of translational research in this field.

Volgin, A. D., Yakovlev, O. A., Demin, K. A., Alekseeva, P. A., Kyzar, E. J., Collins, C., … & Kalueff, A. V. (2018). Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models. ACS chemical neuroscience., 10.1021/acschemneuro.8b00433

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Psychedelic Drugs in Biomedicine

Abstract

Psychedelic drugs, such as lysergic acid diethylamide (LSD), mescaline, and psilocybin, exert profound effects on brain and behavior. After decades of difficulties in studying these compounds, psychedelics are again being tested as potential treatments for intractable biomedical disorders. Preclinical research of psychedelics complements human neuroimaging studies and pilot clinical trials, suggesting these compounds as promising treatments for addiction, depression, anxiety, and other conditions. However, many questions regarding the mechanisms of action, safety, and efficacy of psychedelics remain. Here, we summarize recent preclinical and clinical data in this field, discuss their pharmacological mechanisms of action, and outline critical areas for future studies of psychedelic drugs, with the goal of maximizing the potential benefits of translational psychedelic biomedicine to patients.
Kyzar, E. J., Nichols, C. D., Gainetdinov, R. R., Nichols, D. E., & Kalueff, A. V. (2017). Psychedelic Drugs in Biomedicine. Trends in Pharmacological Sciences. 10.1016/j.tips.2017.08.003
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Anxiolytic-like effects of noribogaine in zebrafish

Abstract

Noribogaine is the main psychoactive metabolite of the hallucinogenic drug ibogaine, and is a particularly interesting compound potentially useful to treat dependence and various psychiatric disorders. Here, we report the effects of noribogaine on anxiety and locomotion in zebrafish (Danio rerio), a new promising model organism in neurobehavioral and psychopharmacological research. Adult zebrafish were subjected to the 5min novel tank test (NTT) following an acute, 20-min drug immersion in 1, 5 and 10mg/L noribogaine. Overall, noribogaine produced robust anxiolytic-like behavior in zebrafish (increasing the time spent and transitions to the top half compartment and reducing freezing bouts) without overt effects on fish locomotion. Taken together, these results indicate that noribogaine modulates the components of the acute stress response related to emotionality and anxiety behaviors, implicating this drug as a potentially useful non-sedative anxiolytic agent.
Kalueff, A. V., Kaluyeva, A., & Mailet, E. L. (2017). Anxiolytic-like effects of noribogaine in zebrafish. Behavioural Brain Research330, 63-67. 10.1016/j.bbr.2017.05.008
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Exploring Hallucinogen Pharmacology and Psychedelic Medicine with Zebrafish Models

Abstract

After decades of sociopolitical obstacles, the field of psychiatry is experiencing a revived interest in the use of hallucinogenic agents to treat brain disorders. Along with the use of ketamine for depression, recent pilot studies have highlighted the efficacy of classic serotonergic hallucinogens, such as lysergic acid diethylamide and psilocybin, in treating addiction, post-traumatic stress disorder, and anxiety. However, many basic pharmacological and toxicological questions remain unanswered with regard to these compounds. In this study, we discuss psychedelic medicine as well as the behavioral and toxicological effects of hallucinogenic drugs in zebrafish. We emphasize this aquatic organism as a model ideally suited to assess both the potential toxic and therapeutic effects of major known classes of hallucinogenic compounds. In addition, novel drugs with hallucinogenic properties can be efficiently screened using zebrafish models. Well-designed preclinical studies utilizing zebrafish can contribute to the reemerging treatment paradigm of psychedelic medicine, leading to new avenues of clinical exploration for psychiatric disorders.

Kyzar, E. J., & Kalueff, A. V. (2016). Exploring Hallucinogen Pharmacology and Psychedelic Medicine with Zebrafish Models. Zebrafish. http://dx.doi.org/10.1089/zeb.2016.1251

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Effects of LSD on grooming behavior in serotonin transporter heterozygous (Sert+/−) mice

Abstract

Serotonin (5-HT) plays a crucial role in the brain, modulating mood, cognition and reward. The serotonin transporter (SERT) is responsible for the reuptake of 5-HT from the synaptic cleft and regulates serotonin signaling in the brain. In humans, SERT genetic variance is linked to the pathogenesis of various psychiatric disorders, including anxiety, autism spectrum disorders (ASD) and obsessive–compulsive disorder (OCD). Rodent self-grooming is a complex, evolutionarily conserved patterned behavior relevant to stress, ASD and OCD. Genetic ablation of mouse Sert causes various behavioral deficits, including increased anxiety and grooming behavior. The hallucinogenic drug lysergic acid diethylamide (LSD) is a potent serotonergic agonist known to modulate human and animal behavior. Here, we examined heterozygous Sert+/− mouse behavior following acute administration of LSD (0.32 mg/kg). Overall, Sert+/− mice displayed a longer duration of self-grooming behavior regardless of LSD treatment. In contrast, LSD increased serotonin-sensitive behaviors, such as head twitching, tremors and backwards gait behaviors in both Sert+/+ and Sert+/− mice. There were no significant interactions between LSD treatment and Sert gene dosage in any of the behavioral domains measured. These results suggest that Sert+/− mice may respond to the behavioral effects of LSD in a similar manner to wild-type mice.

Kyzar, E. J., Stewart, A. M., & Kalueff, A. V. (2016). Effects of LSD on grooming behavior in serotonin transporter heterozygous (Sert+/−) mice. Behavioural brain research, 296, 47-52. http://dx.doi.org/10.1016/j.bbr.2015.08.018
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Characterization of behavioral and endocrine effects of LSD on zebrafish

Abstract

Lysergic acid diethylamide (LSD) is a potent hallucinogenic drug that strongly affects animal and human behavior. Although adult zebrafish (Danio rerio) are emerging as a promising neurobehavioral model, the effects of LSD on zebrafish have not been investigated previously. Several behavioral paradigms (the novel tank, observation cylinder, light–dark box, open field, T-maze, social preference and shoaling tests), as well as modern video-tracking tools and whole-body cortisol assay were used to characterize the effects of acute LSD in zebrafish. While lower doses (5–100 μg/L) did not affect zebrafish behavior, 250 μg/L LSD increased top dwelling and reduced freezing in the novel tank and observation cylinder tests, also affecting spatiotemporal patterns of activity (as assessed by 3D reconstruction of zebrafish traces and ethograms). LSD evoked mild thigmotaxis in the open field test, increased light behavior in the light–dark test, reduced the number of arm entries and freezing in the T-maze and social preference test, without affecting social preference. In contrast, LSD affected zebrafish shoaling (increasing the inter-fish distance in a group), and elevated whole-body cortisol levels. Overall, our findings show sensitivity of zebrafish to LSD action, and support the use of zebrafish models to study hallucinogenic drugs of abuse.

Grossman, L., Utterback, E., Stewarta, A., Gaikwada, S., Chunga, K. M., Suciua, C., … Kalueff, A. V. (2010). Characterization of behavioral and endocrine effects of LSD on zebrafish. Behavioural Brain Research, 214(2), 277-284. http://dx.doi.org/10.1016/j.bbr.2010.05.039
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