OPEN Foundation

Menu
Search
Close this search box.

Papers

Salvinorin A reduces neuropathic nociception in the insular cortex of the rat

October 4, 2017 / Medicine, Neuroscience, Other subjects, Papers, Psychopharmacology, Publications, Salvia / Salvinorin A / By / , , , , , ,

Abstract

BACKGROUND:
Neuropathic pain is one of the most important challenges in public health. The search for novel treatments is important for an adequate relief without adverse effects. In this sense salvinorin A (SA), the main diterpene of the medicinal plant Salvia divinorum is an important antinociceptive compound, which acts as a potent agonist of kappa opioid receptor (KOR) and cannabinoid CB1 receptors.
METHODS:
We evaluated nociceptive responses in a neuropathic pain model induced by the sciatic nerve ligature (SNL) in the right hind paw, after the microinjection of SA, Salvinorin B (SB), KOR and CB1 antagonists directly in the insular cortex (IC) in male wistar rats.
RESULTS:
We found a potent antinociceptive effect with the administration of SA. Moreover, this effect was blocked by the administration of a KOR antagonist as well as the administration of a CB1 antagonist.
CONCLUSION:
Salvinorin A has a potent antinociceptive effect when is administered centrally in the IC by the interaction with KOR and CB1 receptors.
SIGNIFICANCE:
We show evidence on the effectiveness of the administration of salvinorin A in the IC in a rodent model of neuropathic pain. These results support the use of novel compounds like SA as a therapeutic alternative for neuropathic pain relief.
Coffeen, U., Canseco‐Alba, A., Simón‐Arceo, K., Almanza, A., Mercado, F., León‐Olea, M., & Pellicer, F. (2017). Salvinorin A reduces neuropathic nociception in the insular cortex of the rat. European Journal of Pain. 10.1002/ejp.1120
Link to full text

A retrospective study of ketamine administration and the development of acute or post-traumatic stress disorder in 274 war-wounded soldiers

October 3, 2017 / Anxiety disorders / PTSD, Ketamine, Papers, Psychiatry, Psychology, Publications / By / , , ,

Abstract

The objective of this study was to explore whether ketamine prevents or exacerbates acute or post-traumatic stress disorders in military trauma patients. We conducted a retrospective study of a database from the French Military Health Service, including all soldiers surviving a war injury in Afghanistan (2010-2012). The diagnosis of post-traumatic stress disorder was made by a psychiatrist and patients were analysed according to the presence or absence of this condition. Analysis included the following covariables: age; sex; acute stress disorder; blast injury; associated fatality; brain injury; traumatic amputation; Glasgow coma scale; injury severity score; administered drugs; number of surgical procedures; physical, neurosensory or aesthetic sequelae; and the development chronic pain. Covariables related to post-traumatic and acute stress disorders with a p ≤ 0.10 were included in a multivariable logistic regression model. The data from 450 soldiers were identified; 399 survived, of which 274 were analysed. Among these, 98 (36%) suffered from post-traumatic stress disorder and 89 (32%) had received ketamine. Fifty-four patients (55%) in the post-traumatic stress disorder group received ketamine vs. 35 (20%) in the no PTSD group (p < 0.001). The 89 injured soldiers who received ketamine had a median (IQR [range]) injury severity score of 5 (3-13 [1-26]) vs. 3 (2-4 [1-6] in the 185 patients who did not (p < 0.001). At multivariable analysis, only acute stress disorder and total number of surgical procedures were independently associated with the development of post-traumatic stress disorder. In this retrospective study, ketamine administration was not a risk factor for the development of post-traumatic stress disorder in the military trauma setting.
Mion, G., Le Masson, J., Granier, C., & Hoffmann, C. (2017). A retrospective study of ketamine administration and the development of acute or post‐traumatic stress disorder in 274 war‐wounded soldiers. Anaesthesia. 10.1111/anae.14079
Link to full text

Acute LSD effects on response inhibition neural networks

October 2, 2017 / LSD, Neuroscience, Other subjects, Papers, Psychology, Psychopharmacology, Publications / By / , , , , , ,

Abstract

BACKGROUND:
Recent evidence shows that the serotonin 2A receptor (5-hydroxytryptamine2A receptor, 5-HT2AR) is critically involved in the formation of visual hallucinations and cognitive impairments in lysergic acid diethylamide (LSD)-induced states and neuropsychiatric diseases. However, the interaction between 5-HT2AR activation, cognitive impairments and visual hallucinations is still poorly understood. This study explored the effect of 5-HT2AR activation on response inhibition neural networks in healthy subjects by using LSD and further tested whether brain activation during response inhibition under LSD exposure was related to LSD-induced visual hallucinations.
METHODS:
In a double-blind, randomized, placebo-controlled, cross-over study, LSD (100 µg) and placebo were administered to 18 healthy subjects. Response inhibition was assessed using a functional magnetic resonance imaging Go/No-Go task. LSD-induced visual hallucinations were measured using the 5 Dimensions of Altered States of Consciousness (5D-ASC) questionnaire.
RESULTS:
Relative to placebo, LSD administration impaired inhibitory performance and reduced brain activation in the right middle temporal gyrus, superior/middle/inferior frontal gyrus and anterior cingulate cortex and in the left superior frontal and postcentral gyrus and cerebellum. Parahippocampal activation during response inhibition was differently related to inhibitory performance after placebo and LSD administration. Finally, activation in the left superior frontal gyrus under LSD exposure was negatively related to LSD-induced cognitive impairments and visual imagery.
CONCLUSION:
Our findings show that 5-HT2AR activation by LSD leads to a hippocampal-prefrontal cortex-mediated breakdown of inhibitory processing, which might subsequently promote the formation of LSD-induced visual imageries. These findings help to better understand the neuropsychopharmacological mechanisms of visual hallucinations in LSD-induced states and neuropsychiatric disorders.
Schmidt, A., Müller, F., Lenz, C., Dolder, P. C., Schmid, Y., Zanchi, D., … & Borgwardt, S. (2017). Acute LSD effects on response inhibition neural networks. Psychological Medicine, 1-13. 10.1017/S0033291717002914
Link to full text

The relationships of classic psychedelic use with criminal behavior in the United States adult population

October 1, 2017 / Mushrooms / Psilocybin, Other subjects, Papers, Psychology, Publications, Sociology / By / , , , , , ,

Abstract

Criminal behavior exacts a large toll on society and is resistant to intervention. Some evidence suggests classic psychedelics may inhibit criminal behavior, but the extent of these effects has not been comprehensively explored. In this study, we tested the relationships of classic psychedelic use and psilocybin use per se with criminal behavior among over 480,000 United States adult respondents pooled from the last 13 available years of the National Survey on Drug Use and Health (2002 through 2014) while controlling for numerous covariates. Lifetime classic psychedelic use was associated with a reduced odds of past year larceny/theft (aOR = 0.73 (0.65-0.83)), past year assault (aOR = 0.88 (0.80-0.97)), past year arrest for a property crime (aOR = 0.78 (0.65-0.95)), and past year arrest for a violent crime (aOR = 0.82 (0.70-0.97)). In contrast, lifetime illicit use of other drugs was, by and large, associated with an increased odds of these outcomes. Lifetime classic psychedelic use, like lifetime illicit use of almost all other substances, was associated with an increased odds of past year drug distribution. Results were consistent with a protective effect of psilocybin for antisocial criminal behavior. These findings contribute to a compelling rationale for the initiation of clinical research with classic psychedelics, including psilocybin, in forensic settings.
Hendricks, P. S., Crawford, M. S., Cropsey, K. L., Copes, H., Sweat, N. W., Walsh, Z., & Pavela, G. (2017). The relationships of classic psychedelic use with criminal behavior in the United States adult population. Journal of Psychopharmacology, 0269881117735685.
Link to full text

N,N-dimethyltryptamine and the pineal gland: Separating fact from myth

October 1, 2017 / DMT, Mystical experiences, Neuroscience, Papers, Psychology, Psychopharmacology, Publications / By /

Abstract

The pineal gland has a romantic history, from pharaonic Egypt, where it was equated with the eye of Horus, through various religious traditions, where it was considered the seat of the soul, the third eye, etc. Recent incarnations of these notions have suggested that N,N-dimethyltryptamine is secreted by the pineal gland at birth, during dreaming, and at near death to produce out of body experiences. Scientific evidence, however, is not consistent with these ideas. The adult pineal gland weighs less than 0.2 g, and its principal function is to produce about 30 µg per day of melatonin, a hormone that regulates circadian rhythm through very high affinity interactions with melatonin receptors. It is clear that very minute concentrations of N,N-dimethyltryptamine have been detected in the brain, but they are not sufficient to produce psychoactive effects. Alternative explanations are presented to explain how stress and near death can produce altered states of consciousness without invoking the intermediacy of N,N-dimethyltryptamine.
Nichols, D. E. (2017). N, N-dimethyltryptamine and the pineal gland: Separating fact from myth. Journal of Psychopharmacology, 0269881117736919.
Link to full text

The Mechanisms of Psychedelic Visionary Experiences: Hypotheses from Evolutionary Psychology

September 28, 2017 / Mystical experiences, Neuroscience, Other substances, Papers, Psychology, Publications, Religious studies / By /

Abstract

Neuropharmacological effects of psychedelics have profound cognitive, emotional, and social effects that inspired the development of cultures and religions worldwide. Findings that psychedelics objectively and reliably produce mystical experiences press the question of the neuropharmacological mechanisms by which these highly significant experiences are produced by exogenous neurotransmitter analogs. Humans have a long evolutionary relationship with psychedelics, a consequence of psychedelics’ selective effects for human cognitive abilities, exemplified in the information rich visionary experiences. Objective evidence that psychedelics produce classic mystical experiences, coupled with the finding that hallucinatory experiences can be induced by many non-drug mechanisms, illustrates the need for a common model of visionary effects. Several models implicate disturbances of normal regulatory processes in the brain as the underlying mechanisms responsible for the similarities of visionary experiences produced by psychedelic and other methods for altering consciousness. Similarities in psychedelic-induced visionary experiences and those produced by practices such as meditation and hypnosis and pathological conditions such as epilepsy indicate the need for a general model explaining visionary experiences. Common mechanisms underlying diverse alterations of consciousness involve the disruption of normal functions of the prefrontal cortex and default mode network (DMN). This interruption of ordinary control mechanisms allows for the release of thalamic and other lower brain discharges that stimulate a visual information representation system and release the effects of innate cognitive functions and operators. Converging forms of evidence support the hypothesis that the source of psychedelic experiences involves the emergence of these innate cognitive processes of lower brain systems, with visionary experiences resulting from the activation of innate processes based in the mirror neuron system (MNS).
Winkelman, M. J. (2017). The Mechanisms of Psychedelic Visionary Experiences: Hypotheses from Evolutionary Psychology. Frontiers in Neuroscience, 11, 539. 10.3389/fnins.2017.00539
Link to full text

Serotonin 2A Receptor Signaling Underlies LSD-induced Alteration of the Neural Response to Dynamic Changes in Music

September 28, 2017 / LSD, Neuroscience, Other subjects, Papers, Psychology, Psychopharmacology, Publications / By / , , , ,

Abstract

Classic psychedelic drugs (serotonin 2A, or 5HT2A, receptor agonists) have notable effects on music listening. In the current report, blood oxygen level-dependent (BOLD) signal was collected during music listening in 25 healthy adults after administration of placebo, lysergic acid diethylamide (LSD), and LSD pretreated with the 5HT2A antagonist ketanserin, to investigate the role of 5HT2A receptor signaling in the neural response to the time-varying tonal structure of music. Tonality-tracking analysis of BOLD data revealed that 5HT2A receptor signaling alters the neural response to music in brain regions supporting basic and higher-level musical and auditory processing, and areas involved in memory, emotion, and self-referential processing. This suggests a critical role of 5HT2A receptor signaling in supporting the neural tracking of dynamic tonal structure in music, as well as in supporting the associated increases in emotionality, connectedness, and meaningfulness in response to music that are commonly observed after the administration of LSD and other psychedelics. Together, these findings inform the neuropsychopharmacology of music perception and cognition, meaningful music listening experiences, and altered perception of music during psychedelic experiences.
Barrett, F. S., Preller, K. H., Herdener, M., Janata, P., & Vollenweider, F. X. (2017). Serotonin 2A Receptor Signaling Underlies LSD-induced Alteration of the Neural Response to Dynamic Changes in Music. Cerebral Cortex, 1-12. 10.1093/cercor/bhx257
Link to full text

Psychedelic Drugs in Biomedicine

September 22, 2017 / Anxiety disorders / PTSD, Cacti / Mescaline, Depression, LSD, Medicine, Mushrooms / Psilocybin, Neuroscience, Papers, Psychiatry, Psychology, Psychopharmacology, Psychotherapy, Safety, Substance Use Disorder, Toxicology / By / , , , ,

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
Link to full text

Serotonergic hallucinogens in the treatment of anxiety and depression in patients suffering from a life-threatening disease: A systematic review

September 22, 2017 / Anxiety disorders / PTSD, LSD, Mushrooms / Psilocybin, Other substances, Papers, Psychiatry, Psychology, Psychotherapy, Publications / By / , , , , ,

Abstract

Anxiety and depression are some of the most common psychiatric symptoms of patients suffering with life-threatening diseases, often associated with a low quality of life and a poor overall prognosis. 5-HT2A-receptor agonists (serotonergic hallucinogens, ‘psychedelics’) like lysergic acid diethylamide (LSD) and psilocybin were first investigated as therapeutic agents in the 1960s. Recently, after a long hiatus period of regulatory obstacles, interest in the clinical use of these substances has resumed. The current article provides a systematic review of studies investigating psychedelics in the treatment of symptoms of existential distress in life-threatening diseases across different periods of research, highlighting how underlying concepts have developed over time. A systematic search for clinical trials from 1960 to 2017 revealed 11 eligible clinical trials involving a total number of N=445 participants, of which 7 trials investigated the use of lysergic acid diethylamide (LSD) (N=323), 3 trials investigated the use of psilocybin (N=92), and one trial investigated the use of dipropyltryptamine (DPT) (N=30). The 4 more recent randomized controlled trials (RCTs) (N=104) showed a significantly higher methodological quality than studies carried out in the 1960s and 1970s. Evidence supports that patients with life threatening diseases associated with symptoms of depression and anxiety benefit from the anxiolytic and antidepressant properties of serotonergic hallucinogens. Some studies anecdotally reported improvements in patients´ quality of life and reduced fear of death. Moreover, low rates of side effects were reported in studies that adhered to safety guidelines. Further studies are needed to determine how these results can be transferred into clinical practice.
Reiche, S., Hermle, L., Gutwinski, S., Jungaberle, H., Gasser, P., & Majić, T. (2017). Serotonergic hallucinogens in the treatment of anxiety and depression in patients suffering from a life-threatening disease: A systematic review. Progress in Neuro-Psychopharmacology and Biological Psychiatry. 10.1016/j.pnpbp.2017.09.012
Link to full text

Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations

September 21, 2017 / LSD, Neuroscience, Other subjects, Papers, Psychopharmacology, Publications / By / , , , , , ,

Abstract

OBJECTIVE:
It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system.
METHOD:
100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects.
RESULTS:
LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects.
CONCLUSION:
Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT2A -receptor in altered states of consciousness.
Mueller, F., Lenz, C., Dolder, P., Lang, U., Schmidt, A., Liechti, M., & Borgwardt, S. (2017). Increased thalamic resting‐state connectivity as a core driver of LSD‐induced hallucinations. Acta Psychiatrica Scandinavica. 10.1111/acps.12818
Link to full text