The serotonin transporter (SERT) belongs to the monoamine transporter family, which also includes the dopamine and norepinephrine transporters. SERT is essential for regulating serotonergic signaling by the reuptake of serotonin from the synaptic cleft back into the presynaptic neuron. Dysregulation of SERT has been implicated in several major psychiatric disorders such as major depressive...
Abstract Psychedelic agonists of serotonin receptors induce neural plasticity and synaptogenesis, but their potential to enhance learning remains uncharted. Here we show that a single dose of d-LSD, a potent serotonergic agonist, increased novel object preference in young and adult rats several days after treatment. d-LSD alone did not increase preference in old animals, but could rescue it to...
Background: 2,4,5-Trimethoxyamphetamine (TMA-2) is a potent psychedelic compound. Structurally related 4-alkyloxy-substituted 2,5-dimethoxyamphetamines and phenethylamine congeners (2C-O derivatives) have been described but their pharmacology is mostly undefined. Therefore, we examined receptor binding and activation profiles of these derivatives at monoamine receptors and transporters....
The ergoline d-lysergic acid diethylamide (LSD) is one of the most potent psychedelic drugs. 1-Acetyl-LSD (ALD-52), a derivative of LSD containing an acetyl group on the indole nitrogen, also produces psychedelic effects in humans and has about the same potency as LSD. Recently, several other 1-acyl-substitued LSD derivatives, including 1-propanoyl-LSD (1P-LSD) and 1-butanoyl-LSD (1B-LSD), have...
Classic or serotonergic hallucinogens comprise the third largest number of reported new psychoactive substances (NPS), according to the United Nations Office on Drugs and Crime. While being structurally very divergent, they share activation of the serotonin 2A receptor (5-HT2AR), a G protein-coupled receptor, as their main pharmacological mechanism. Here, we report on the development of a...
Purpose: Like other psychedelics, D-lysergic acid diethylamide (LSD) affects numerous serotonin receptors, and according to the current dogma, the 5-HT 2A receptors are considered the main target for its hallucinogenic effects. LSD, however, also displays agonistic activity at the 5-HT 5A receptors, which mediate some of LSD-induced behavioural effects. Methods: Using male Sprague Dawley rats,...
4-bromo-2,5-dimethoxyphenethylamine (2C-B) is a designer drug. In Europe, 2C-B is easily obtained and used for recreational purposes. It is known for its stimulating effects similar to those of 3,4-methylenedioxymethamphetamine, although in higher doses it has more hallucinogenic effects. Here, we report a case of 2C-B ingestion, confirmed by liquid chromatography-tandem mass spectrometry, in...
In a recent issue of the BMC Psychiatry, the evidence of effectiveness of treatments for psychiatric conditions in end-stage cancer patients was reviewed (Johnson, 2018). The review was comprehensive, and included traditional and non-traditional/alternative treatments, including herbal medicines and spirituality. However, evidence showing that classic or serotonergic hallucinogens/psychedelics...
Abstract Head-twitch behavior (HTR) is the behavioral signature of psychedelic drugs upon stimulation of the serotonin 5-HT 2A receptor (5-HT 2A R) in rodents. Following the previous report of a semi-automated detection of HTR based on the dynamics of mouse’s head movement, here we present a system for the identification of individual HTR events in a fully automated fashion. The validity of...
Lysergic acid diethylamide (LSD) is a potent hallucinogenic substance that was extensively investigated by psychiatrists during the 1950s and 1960s. Researchers were interested in the unique effects induced by this substance, some of which resemble symptoms seen in schizophrenia. Moreover, during that period LSD was studied and used for the treatment of several mental disorders such as...
Abstract 5-Methoxy-N,N-dimethyltryptamine (acronymized as 5-MeO-DMT) is sui generis among the numerous naturally-occurring psychoactive substances due to its unparalleled ego-dissolving effects which can culminate in a state of nondual consciousness (which is phenomenologically similar to transformative peak experiences described in various ancient contemplative traditions, e.g., Advaita...
BACKGROUND: Although recent studies provide insight into the molecular mechanisms of the effects of ketamine, the antidepressant mechanism of ketamine enantiomers and their metabolites is not fully understood. In view of the involvement of mechanisms other than the N-methyl-D-aspartate receptor in ketamine's action, we investigated the effects of (R)-ketamine, (S)-ketamine, (R)-norketamine...
Ketamine, a non-competitive antagonist of N-methyl-D-aspartate (NMDA) receptor, displays a fast antidepressant activity in treatment-resistant depression and in rodent models of anxiety/depression. A large body of evidence concerning the cellular and molecular mechanisms underlying its fast antidepressant-like activity comes from animal studies. Although structural remodeling of...
N,N-dimethyltryptamine (DMT), a psychedelic compound identified endogenously in mammals, is biosynthesized by aromatic-L-amino acid decarboxylase (AADC) and indolethylamine-N-methyltransferase (INMT). Whether DMT is biosynthesized in the mammalian brain is unknown. We investigated brain expression of INMT transcript in rats and humans, co-expression of INMT and AADC mRNA in rat brain and...
Classic serotonergic psychedelics are remarkable for their capacity to induce reversible alterations in consciousness of the self and the surroundings, mediated by agonism at serotonin 5-HT2A receptors. The subjective effects elicited by dissociative drugs acting as N-methyl-D-aspartate (NMDA) antagonists (e.g. ketamine and phencyclidine) overlap in certain domains with those of serotonergic...
Serotonergic psychedelics are emerging as potential antidepressant therapeutic tools, as suggested in a recent randomized controlled trial with ayahuasca for treatment-resistant depression. Preclinical and clinical studies have suggested that serum brain-derived neurotrophic factor (BDNF) levels increase after treatment with serotoninergic antidepressants, but the exact role of BDNF as a...
Most studies on discriminative stimulus effects of 3,4-methylenedioxymethamphetamine (MDMA) have been conducted using a relatively low dose (1.5 mg/kg), and those studies have invariably implicated serotonergic mechanisms. In contrast, dopaminergic mechanisms mediate the discriminative stimulus effects of amphetamine (AMPH). Some studies have suggested that the discriminative stimulus effects...
Abstract Objective: Psilocybin is a serotonin receptor agonist with a therapeutic potential for treatment-resistant depression and other psychiatric illnesses. We investigated whether the administration of psilocybin had an antidepressant-like effect in a rat model of depression. Methods: Using the Flinders Sensitive Line (FSL) rat model of depression, we assessed the antidepressant-like effect...
The serotonin transporter (SERT) regulates neurotransmitter homeostasis through the sodium- and chloride-dependent recycling of serotonin into presynaptic neurons1-3. Major depression and anxiety disorders are treated using selective serotonin reuptake inhibitors-small molecules that competitively block substrate binding and thereby prolong neurotransmitter action2,4. The dopamine and...
Background: Amphetamine analogs with a 3,4-methylenedioxy ring-substitution are among the most popular illicit drugs of abuse, exerting stimulant and entactogenic effects. Enzymatic N-demethylation or opening of the 3,4-methylenedioxy ring via O-demethylenation gives rise to metabolites that may be pharmacologically active. Indeed, previous studies in rats show that specific metabolites of...