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LSD

Salvinorin A fails to substitute for the discriminative stimulus effects of LSD or ketamine in Sprague–Dawley rats

Abstract

Salvia divinorum is a small perennial shrub that has gained recent popularity among the drug-using subculture as a legal alternative to hallucinogens. Salvinorin A, the main active compound found in the S. divinorum plant, is an atypical hallucinogen with pharmacological selectivity at kappa opioid (KOP) receptor sites and is a unique non-nitrogenous neoclerodane diterpene which is structurally distinct from other opioid compounds. The novel structure of salvinorin A and its specific binding affinity to KOP receptors provide a unique opportunity to investigate neurochemical mechanisms of hallucination and hallucinogenic compounds. The current investigation assessed the substitution of salvinorin A in 16 male Sprague–Dawley rats trained to discriminate either the prototypical serotonergic hallucinogen, LSD (0.08 mg/kg, S.C., n = 8) or the dissociative anesthetic and glutamatergic hallucinogen, ketamine (8.0 mg/kg, I.P., n = 8) from vehicle under a FR 20 schedule of food-reinforced responding. Results indicated that neither LSD nor ketamine discrimination generalized to salvinorin A. These findings are consistent with the growing body of evidence that salvinorin A is pharmacologically distinct from other traditional hallucinogenic compounds.

Killingera, B. A., Peeta, M. M., & Baker, L. E. (2010). Salvinorin A fails to substitute for the discriminative stimulus effects of LSD or ketamine in Sprague–Dawley rats. Pharmacology Biochemistry and Behavior, 96(3), 260-265. http://dx.doi.org/10.1016/j.pbb.2010.05.014
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Abnormal visual experiences in individuals with histories of hallucinogen use: A web-based questionnaire

Abstract

Despite longstanding reports of prolonged or reoccurring perceptual changes in a subset of hallucinogen users, very little is known about Hallucinogen Persisting Perception Disorder and related visual abnormalities in hallucinogen users. We used an online questionnaire to document the symptoms and relationship to drug use of unusual visual phenomena in hallucinogen users. 16,192 individuals viewed the information sheet and 2679 were included in the study. Of these, 224 reported having unrelated diagnoses associated with unusual visual experiences and were excluded from main analyses. Most (60.6%) of the remaining 2455 participants reported having experienced drug-free visual experiences that resembled hallucinogen effects. Probability of experiencing constant or near-constant symptoms was predicted by greater past exposure to specific hallucinogens, including lysergic acid diethylamide (LSD). Although symptoms were common, few (104, or 4.2% of the sample) found them distressing or impairing enough to consider seeking treatment. Visual changes in hallucinogen users may be more common than previously suspected and are worthy of further study.

Baggott, M. J., Coyle, J. R., Erowid, E., Erowid, F., & Robertson, L. C. (2011). Abnormal visual experiences in individuals with histories of hallucinogen use: A web-based questionnaire. Drug and alcohol dependence, 114(1), 61-67. http://dx.doi.org/10.1016/j.drugalcdep.2010.09.006
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The neurobiology of psychedelic drugs: implications for the treatment of mood disorders

Abstract

After a pause of nearly 40 years in research into the effects of psychedelic drugs, recent advances in our understanding of the neurobiology of psychedelics, such as lysergic acid diethylamide (LSD), psilocybin and ketamine have led to renewed interest in the clinical potential of psychedelics in the treatment of various psychiatric disorders. Recent behavioural and neuroimaging data show that psychedelics modulate neural circuits that have been implicated in mood and affective disorders, and can reduce the clinical symptoms of these disorders. These findings raise the possibility that research into psychedelics might identify novel therapeutic mechanisms and approaches that are based on glutamate-driven neuroplasticity.

Vollenweider, F. X., & Kometer, M. (2010). The neurobiology of psychedelic drugs: implications for the treatment of mood disorders. Nature Reviews Neuroscience, 11, 642-651. http://dx.doi.org/10.1038/nrn2884
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Intrahippocampal LSD accelerates learning and desensitizes the 5-HT2A receptor in the rabbit

Abstract

Rationale: Parenteral injections of d-lysergic acid diethylamide (LSD), a serotonin 5-HT2A receptor agonist, enhance eyeblink conditioning. Another hallucinogen, (±)-1(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), was shown to elicit a 5-HT2A-mediated behavior (head bobs) after injection into the hippocampus, a structure known to mediate trace eyeblink conditioning.

Objective: This study aims to determine if parenteral injections of the hallucinogens LSD, d,l-2,5-dimethoxy-4-methylamphetamine, and 5-methoxy-dimethyltryptamine elicit the 5-HT2A-mediated behavior of head bobs and whether intrahippocampal injections of LSD would produce head bobs and enhance trace eyeblink conditioning.

Materials and methods: LSD was infused into the dorsal hippocampus just prior to each of eight conditioning sessions. One day after the last infusion of LSD, DOI was infused into the hippocampus to determine whether there had been a desensitization of the 5-HT2A receptor as measured by a decrease in DOI-elicited head bobs.

Results: Acute parenteral or intrahippocampal LSD elicited a 5-HT2A but not a 5-HT2C-mediated behavior, and chronic administration enhanced conditioned responding relative to vehicle controls. Rabbits that had been chronically infused with 3 or 10 nmol per side of LSD during Pavlovian conditioning and then infused with DOI demonstrated a smaller increase in head bobs relative to controls.

Conclusions: LSD produced its enhancement of Pavlovian conditioning through an effect on 5-HT2A receptors located in the dorsal hippocampus. The slight, short-lived enhancement of learning produced by LSD appears to be due to the development of desensitization of the 5-HT2A receptor within the hippocampus as a result of repeated administration of its agonist (LSD).

Romano, A. G., Quinn, J. L., Li, L., Dave, K. D., Schindler, E. A., Aloyo, V. J., & Harvey, J. A. (2010). Intrahippocampal LSD accelerates learning and desensitizes the 5-HT2A receptor in the rabbit. Psychopharmacology, 212(3), 441–448. http://dx.doi.org/10.1007/s00213-010-2004-7
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The non-hallucinogen 2-bromo-lysergic acid diethylamide as preventative treatment for cluster headache: An open, non-randomized case series

Introduction

Cluster headache (CH) is a stereotyped primary headache characterized by strictly unilateral severe orbital or periorbital pain and categorized as either episodic or chronic (1,2). Its prevalence is 0.1% (3). Oxygen and sumatriptan are the treatments of choice for individual attacks, whereas verapamil, lithium, corticosteroids and other neuromodulators can suppress attacks during cluster periods (1). All standard medication treatments may be ineffective. Surgical treatment may be an option for medication non-responders, including deep brain (4) or occipital nerve stimulation (5). However, serious complications from brain surgery, including death, can occur (6).

An Internet survey of 53 CH patients reported on claims that psilocybin is better at aborting acute attacks than either oxygen or sumatriptan and that LSD and psilocybin are both better at triggering and extending remission than standard drugs (7). However, due to hallucinogenicity and the absence of established medical indication, these drugs are criminalized and placed within the most restrictive Schedule I of the Controlled Substances Act, which sanctions only limited research use. Although the hallucinogenic properties of LSD and psilocybin are undesirable from both regulatory and patient safety perspectives, it was unclear to us at the outset whether a non-hallucinogenic analog could also provide meaningful relief to CH patients. To address the question of whether the CH relief associated with these two structurally diverse compounds is related to the mechanisms triggering intoxication, we decided to investigate the efficacy of a non-hallucinogenic analog of LSD. LSD’s hallucinogenic effects are completely lost when the double bond in the D ring is saturated and with substitution at R2 (e.g. by bromination in 2-bromo-LSD) (BOL-148) (8). BOL-148 has been studied in volunteers (up to 20 mg per os) (9) and in patients suffering from vascular headaches but not, apparently, in patients with CH (9,10). These past studies [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”][…]

Karst, M., Halpern, J. H., Bernateck, M., & Passie, T. (2010). The non-hallucinogen 2-bromo-lysergic acid diethylamide as preventative treatment for cluster headache: An open, non-randomized case series. Cephalalgia, 30(9), 1140-1144. https://dx.doi.org/10.1177/0333102410363490
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The persistence of the subjective in neuropsychopharmacology: observations of contemporary hallucinogen research

Abstract

The elimination of subjectivity through brain research and the replacement of so-called ‘folk psychology’ by a neuroscientifically enlightened worldview and self-conception has been both hoped for and feared. But this cultural revolution is still pending. Based on nine months of fieldwork on the revival of hallucinogen research since the ‘Decade of the Brain,’ this paper examines how subjective experience appears as epistemic object and practical problem in a psychopharmacological laboratory. In the quest for neural correlates of (drug-induced altered states of) consciousness, introspective accounts of test subjects play a crucial role in neuroimaging studies. Firsthand knowledge of the drugs’ flamboyant effects provides researchers with a personal knowledge not communicated in scientific publications, but key to the conduct of their experiments. In many cases, the ‘psychedelic experience’ draws scientists into the field and continues to inspire their self-image and way of life. By exploring these domains the paper points to a persistence of the subjective in contemporary neuropsychopharmacology.

Langlitz, N. (2010). The persistence of the subjective in neuropsychopharmacology: observations of contemporary hallucinogen research. History of Human Sciences, 23(1), 37-57. http://dx.doi.org/10.1177/0952695109352413
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LSD but not lisuride disrupts prepulse inhibition in rats by activating the 5-HT2A receptor

Abstract

Rationale: Compounds that activate the 5-HT2A receptor, such as lysergic acid diethylamide (LSD), act as hallucinogens in humans. One notable exception is the LSD congener lisuride, which does not have hallucinogenic effects in humans even though it is a potent 5-HT2A agonist. LSD and other hallucinogens have been shown to disrupt prepulse inhibition (PPI), an operational measure of sensorimotor gating, by activating 5-HT2A receptors in rats.

Objective: We tested whether lisuride disrupts PPI in male Sprague–Dawley rats. Experiments were also conducted to identify the mechanism(s) responsible for the effect of lisuride on PPI and to compare the effects of lisuride to those of LSD.

Results: Confirming a previous report, LSD (0.05, 0.1, and 0.2 mg/kg, s.c.) reduced PPI, and the effect of LSD was blocked by pretreatment with the selective 5-HT2A antagonist MDL 11,939. Administration of lisuride (0.0375, 0.075, and 0.15 mg/kg, s.c.) also reduced PPI. However, the PPI disruption induced by lisuride (0.075 mg/kg) was not blocked by pretreatment with MDL 11,939 or the selective 5-HT1A antagonist WAY-100635 but was prevented by pretreatment with the selective dopamine D2/D3 receptor antagonist raclopride (0.1 mg/kg, s.c).

Conclusions: The effect of LSD on PPI is mediated by the 5-HT2A receptor, whereas activation of the 5-HT2A receptor does not appear to contribute to the effect of lisuride on PPI. These findings demonstrate that lisuride and LSD disrupt PPI via distinct receptor mechanisms and provide additional support for the classification of lisuride as a non-hallucinogenic 5-HT2A agonist.

Halberstadt, A. L, & Geyer, M. A. (2010). LSD but not lisuride disrupts prepulse inhibition in rats by activating the 5-HT2A receptor. Psychopharmacology, 208(2), 179–189. http://dx.doi.org/10.1007/s00213-009-1718-x
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Gaddum and LSD: the birth and growth of experimental and clinical neuropharmacology research on 5-HT in the UK

Abstract

The vasoconstrictor substance named serotonin was identified as 5-hydroxytryptamine (5-HT) by Maurice Rapport in 1949. In 1951, Rapport gave Gaddum samples of 5-HT substance allowing him to develop a bioassay to both detect and measure the amine. Gaddum and colleagues rapidly identified 5-HT in brain and showed that lysergic acid diethylamide (LSD) antagonized its action in peripheral tissues. Gaddum accordingly postulated that 5-HT might have a role in mood regulation. This review examines the role of UK scientists in the first 20 years following these major discoveries, discussing their role in developing assays for 5-HT in the CNS, identifying the enzymes involved in the synthesis and metabolism of 5-HT and investigating the effect of drugs on brain 5-HT. It reviews studies on the effects of LSD in humans, including Gaddum’s self-administration experiments. It outlines investigations on the role of 5-HT in psychiatric disorders, including studies on the effect of antidepressant drugs on the 5-HT concentration in rodent and human brain, and the attempts to examine 5-HT biochemistry in the brains of patients with depressive illness. It is clear that a rather small group of both preclinical scientists and psychiatrists in the UK made major advances in our understanding of the role of 5-HT in the brain, paving the way for much of the knowledge now taken for granted when discussing ways that 5-HT might be involved in the control of mood and the idea that therapeutic drugs used to alleviate psychiatric illness might alter the function of cerebral 5-HT.

Green, A. R. (2008). Gaddum and LSD: the birth and growth of experimental and clinical neuropharmacology research on 5‐HT in the UK. British journal of pharmacology154(8), 1583-1599., 10.1038/bjp.2008.207
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Unauthorized Research on Cluster Headache

Perhaps the greatest triumph of unauthorized research on visionary plants and drugs to date is the discovery that small doses of LSD, psilocybin, and LSA (lysergic acid amide) are more effective than any conventional medication in treating the dismal disorder, cluster headache. Five years ago, no one other than cluster headache patients or neurologists had ever heard of cluster headache. Now, treatment of cluster headache is routinely listed among potential therapeutic uses for psychedelics, and has even penetrated popular culture to the point that the character Gregory House, M.D. has used a psychedelic drug to treat headache on the TV show House not once, but twice (Kaplow 2006; Dick 2007)!

The first mention of therapeutic effect from a psychedelic on headache comes from Drs. D. Webster Prentiss and Francis P. Morgan, professors of medicine and pharmacology at Columbian University (now George Washington University), who began to conduct animal and human experiments with peyote in 1894 in order to determine whether or not it had any valuable medicinal properties. Two years later, their report concluded: “The conditions in which it seems probable that the use of mescal buttons will produce beneficial results are the following: In general ‘nervousness,’ nervous headache, nervous irritative cough… [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”][etc.].” In their account are a number of cases, including #5: “The same gentleman reports that his wife formerly used to take the tincture [anhalonium 1] for nervous headaches and that it always relieved her. She has them so seldom now that she does not use it” (Prentiss & Morgan 1896).

Sewell, R. A. (2008). Unauthorized Research on Cluster Headache. The Entheogen Review, 16(4), 117-125.
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The Pharmacology of Lysergic Acid Diethylamide: A Review

Abstract

Lysergic acid diethylamide (LSD) was synthesized in 1938 and its psychoactive effects discovered in 1943. It was used during the 1950s and 1960s as an experimental drug in psychiatric research for producing so-called “experimental psychosis” by altering neurotransmitter system and in psychotherapeutic procedures (“psycholytic” and “psychedelic” therapy). From the mid 1960s, it became an illegal drug of abuse with widespread use that continues today. With the entry of new methods of research and better study oversight, scientific interest in LSD has resumed for brain research and experimental treatments. Due to the lack of any comprehensive review since the 1950s and the widely dispersed experimental literature, the present review focuses on all aspects of the pharmacology and psychopharmacology of LSD. A thorough search of the experimental literature regarding the pharmacology of LSD was performed and the extracted results are given in this review. (Psycho-) pharmacological research on LSD was extensive and produced nearly 10,000 scientific papers. The pharmacology of LSD is complex and its mechanisms of action are still not completely understood. LSD is physiologically well tolerated and psychological reactions can be controlled in a medically supervised setting, but complications may easily result from uncontrolled use by layman. Actually there is new interest in LSD as an experimental tool for elucidating neural mechanisms of (states of) consciousness and there are recently discovered treatment options with LSD in cluster headache and with the terminally ill.

Passie, T., Halpern, J. H.,  Stichtenoth, D. O., Emrich, H. M., & Hintzen, A. (2008). The Pharmacology of Lysergic Acid Diethylamide: A Review. CNS Neuroscience & Therapeutics, 14(4), 295–314. http://dx.doi.org/10.1111/j.1755-5949.2008.00059.x
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