Serotonin 1A Receptors Modulate Serotonin 2A Receptor-Mediated Behavioral Effects of 5-Methoxy-,-dimethyltryptamine Analogs in Mice.

5-methoxy-,-dimethyltrytpamine (5-MeO-DMT) analogs are used as recreational drugs, but they are also being developed as potential medicines, warranting further investigation into their pharmacology. Here, we investigated the neuropharmacology of 5-MeO-DMT and several of its -alkyl, -allyl, and 2-methyl analogs, with three major aims: 1) to determine in vitro receptor profiles for the compounds, 2) to characterize in vitro functional activities at serotonin (5-HT) 2A receptors (5-HT) and 1A receptors (5-HT), and 3) to examine the influence of 5-HT on 5-HT-mediated psychedelic-like effects in the mouse head twitch response (HTR) model. In vitro receptor binding and functional assays showed that all 5-MeO-DMT analogs bind with high affinity and activate multiple targets (e.

Reinforcing effects of fentanyl analogs found in illicit drug markets.

Rationale: The potent synthetic opioid fentanyl, and its analogs, continue to drive opioid-related overdoses. Although the pharmacology of fentanyl is well characterized, there is little information about the reinforcing effects of clandestine fentanyl analogs (FAs).

Objectives: Here, we compared the effects of fentanyl and the FAs acetylfentanyl, butyrylfentanyl, and cyclopropylfentanyl on drug self-administration in male and female rats.

Comparative Pharmacological Effects of Lisuride and Lysergic Acid Diethylamide Revisited.

Lisuride is a non-psychedelic serotonin (5-HT) 2A receptor (5-HT) agonist and analogue of the psychedelic lysergic acid diethylamide (LSD). Lisuride also acts as an agonist at the serotonin 1A receptor (5-HT), a property known to counter psychedelic effects. Here, we tested whether lisuride lacks psychedelic activity due to a dual mechanism: (1) partial agonism at 5-HT and (2) potent agonism at 5-HT.

Psychedelic-like Activity of Norpsilocin Analogues.

Primary metabolites of mushroom tryptamines, psilocybin and baeocystin (i.e., psilocin and norpsilocin), exhibit potent agonist activity at the serotonin 2A receptor (5-HT) but differ in their 5-HT-mediated effects .

Alkoxy chain length governs the potency of 2-benzylbenzimidazole 'nitazene' opioids associated with human overdose.

Rationale: Novel synthetic opioids (NSOs) are emerging in recreational drug markets worldwide. In particular, 2-benzylbenzimidazole 'nitazene' compounds are problematic NSOs associated with serious clinical consequences, including fatal respiratory depression. Evidence from in vitro studies shows that alkoxy chain length can influence the potency of nitazenes at the mu-opioid receptor (MOR).

Comparative neuropharmacology of structurally distinct non-fentanyl opioids that are appearing on recreational drug markets worldwide.

Background: The emergence of novel synthetic opioids (NSOs) is contributing to the opioid overdose crisis. While fentanyl analogs have historically dominated the NSO market, a shift towards non-fentanyl compounds is now occurring.

Methods: Here, we examined the neuropharmacology of structurally distinct non-fentanyl NSOs, including U-47700, isotonitazene, brorphine, and N-desethyl isotonitazene, as compared to morphine and fentanyl.

Receptor Binding Profiles for Tryptamine Psychedelics and Effects of 4-Propionoxy--dimethyltryptamine in Mice.

Analogues of 4-phosphoryloxy--dimethyltryptamine (psilocybin) are being sold on recreational drug markets and developed as potential medications for psychedelic-assisted therapies. Many of these tryptamine-based psilocybin analogues produce psychedelic-like effects in rodents and humans primarily by agonist activity at serotonin 2A receptors (5-HT). However, the comprehensive pharmacological target profiles for these compounds compared to psilocybin and its active metabolite 4-hydroxy--dimethyltryptamine (psilocin) are unknown.

Plasma pharmacokinetics and pharmacodynamic effects of the 2-benzylbenzimidazole synthetic opioid, isotonitazene, in male rats.

Rationale: Isotonitazene is an illicit synthetic opioid associated with many intoxications and fatalities. Recent studies show that isotonitazene is a potent µ-opioid receptor (MOR) agonist in vitro, but little information is available about its in vivo effects.

Objectives: The aims of the present study were to investigate the pharmacokinetics of isotonitazene in rats, and relate pharmacokinetic parameters to pharmacodynamic effects.

Structure-Activity Relationships for Psilocybin, Baeocystin, Aeruginascin, and Related Analogues to Produce Pharmacological Effects in Mice.

4-Phosphoryloxy-,-dimethyltryptamine (psilocybin) is a naturally occurring tertiary amine found in many mushroom species. Psilocybin is a prodrug for 4-hydroxy-,-dimethyltryptamine (psilocin), which induces psychedelic effects via agonist activity at the serotonin (5-HT) 2A receptor (5-HT). Several other 4-position ring-substituted tryptamines are present in psilocybin-containing mushrooms, including the secondary amine 4-phosphoryloxy--methyltryptamine (baeocystin) and the quaternary ammonium 4-phosphoryloxy-,,-trimethyltryptamine (aeruginascin), but these compounds are not well studied.

Methods to Assess Melatonin Receptor-Mediated Phase-Shift and Re-entrainment of Rhythmic Behaviors in Mouse Models.

The neurohormone melatonin facilitates entrainment of biological rhythms to environmental light-dark conditions as well as phase-shifts of circadian rhythms in constant conditions via activation of the MT and/or MT receptors expressed within the suprachiasmatic nucleus of the hypothalamus. The efficacy of melatonin and related agonists to modulate biological rhythms can be assessed using two well-validated mouse models of rhythmic behaviors. These models serve as predictive measures of therapeutic efficacy for treatment of circadian phase disorders caused by internal (e.

Synthesis, Structural Characterization, and Pharmacological Activity of Novel Quaternary Salts of 4-Substituted Tryptamines.

Aeruginascin (4-phosphoryloxy-,,-trimethyltryptammonium) is an analogue of psilocybin (4-phosphoryloxy-,-dimethyltryptamine) that has been identified in several species of psilocybin-containing mushrooms. Our team previously reported the synthesis, structural characterization, and biological activity of the putative metabolite of aeruginascin (4-hydroxy-,,-trimethyltryptammonium; 4-HO-TMT) and its potential prodrug (4-acetoxy-,,-trimethyltryptammonium; 4-AcO-TMT). Here, we report the synthesis, structural characterization, and pharmacological activity of several quaternary tryptammonium analogues of 4-HO-TMT and 4-AcO-TMT, namely, 4-hydroxy-,-dimethyl--ethyltryptammonium (4-HO-DMET), 4-hydroxy-,-dimethyl---propyltryptammonium (4-HO-DMPT), and 4-hydroxy-,-dimethyl--isopropyltryptammonium (4-HO-DMiPT), as well as their hypothesized prodrugs 4-acetoxy-,-dimethyl--ethyltryptammonium (4-AcO-DMET), 4-acetoxy-,-dimethyl---propyltryptammonium (4-AcO-DMPT), and 4-acetoxy-,-dimethyl--isopropyltryptammonium (4-AcO-DMiPT).

Automated Computer Software Assessment of 5-Hydroxytryptamine 2A Receptor-Mediated Head Twitch Responses from Video Recordings of Mice.

Psychedelics are a class of drugs that produce unique subjective effects via agonist actions at the 5-hydroxytryptamine 2A receptor (5-HT). The 5-HT-mediated head twitch response (HTR) in rodents is used as a reliable proxy for psychedelic drug activity in humans, but existing methods for measuring HTRs require surgery or time-consuming visual scoring. In the present work, we validated a simple noninvasive method for quantitating HTRs using computer-based analysis of experimental video recordings.

Pharmacological evaluation and forensic case series of N-pyrrolidino etonitazene (etonitazepyne), a newly emerging 2-benzylbenzimidazole 'nitazene' synthetic opioid.

Novel synthetic opioids continue to emerge on recreational drug markets worldwide. In response to legislative bans on fentanyl analogues, non-fentanyl structural templates, such as 2-benzylbenzimidazoles ('nitazenes'), are being exploited to create new μ-opioid receptor (MOR) agonists. Here, we pharmacologically characterize an emerging cyclic analogue of etonitazene, called N-pyrrolidino etonitazene (etonitazepyne), using in vitro and in vivo methods.

First identification, chemical analysis and pharmacological characterization of N-piperidinyl etonitazene (etonitazepipne), a recent addition to the 2-benzylbenzimidazole opioid subclass.

N-Piperidinyl etonitazene ('etonitazepipne') represents a recent addition to the rapidly expanding class of 2-benzylbenzimidazole 'nitazene' opioids. Following its first identification in an online-sourced powder and in biological samples from a patient seeking help for detoxification, this report details its in-depth chemical analysis and pharmacological characterization. Analysis of the powder via different techniques (LC-HRMS, GC-MS, UHPLC-DAD, FT-IR) led to the unequivocal identification of N-piperidinyl etonitazene.

Structure-activity relationships for 5F-MDMB-PICA and its 5F-pentylindole analogs to induce cannabinoid-like effects in mice.

Synthetic cannabinoid receptor agonists (SCRAs) are an evolving class of new psychoactive substances found on recreational drug markets worldwide. The indole-containing compound, 5F-MDMB-PICA, is a popular SCRA associated with serious medical consequences, including overdose and hospitalizations. In vitro studies reveal that 5F-MDMB-PICA is a potent agonist at cannabinoid type 1 receptors (CB), but little information exists regarding in vivo pharmacology of the drug.

(2-Aminopropyl)benzo[β]thiophenes (APBTs) are novel monoamine transporter ligands that lack stimulant effects but display psychedelic-like activity in mice.

Derivatives of (2-aminopropyl)indole (API) and (2-aminopropyl)benzofuran (APB) are new psychoactive substances which produce stimulant effects in vivo. (2-Aminopropyl)benzo[β]thiophene (APBT) is a novel sulfur-based analog of API and APB that has not been pharmacologically characterized. In the current study, we assessed the pharmacological effects of six APBT positional isomers in vitro, and three of these isomers (3-APBT, 5-APBT, and 6-APBT) were subjected to further investigations in vivo.

Eutylone and Its Structural Isomers Interact with Monoamine Transporters and Induce Locomotor Stimulation.

Synthetic cathinones are a class of new psychoactive substances that induce psychostimulant effects and pose risk for hospitalizations, overdose, and death. At the present time, derivatives of the synthetic cathinone, methylone, are being confiscated in nonmedical (i.e.

Virtual discovery of melatonin receptor ligands to modulate circadian rhythms.

The neuromodulator melatonin synchronizes circadian rhythms and related physiological functions through the actions of two G-protein-coupled receptors: MT and MT. Circadian release of melatonin at night from the pineal gland activates melatonin receptors in the suprachiasmatic nucleus of the hypothalamus, synchronizing the physiology and behaviour of animals to the light-dark cycle. The two receptors are established drug targets for aligning circadian phase to this cycle in disorders of sleep and depression.