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Salvinorin A (SA) is a κ-opioid receptor agonist and atypical dissociative hallucinogen found in Salvia divinorum . Despite the resurgence of hallucinogen studies, the effects of κ-opioid agonists on human brain function are not well-understood. This placebo-controlled, within-subject study used functional magnetic resonance imaging for the first time to explore the effects of inhaled SA on strength, variability, and entropy of functional connectivity (static, dynamic, and entropic functional connectivity, respectively, or sFC, dFC, and eFC). SA tended to decrease within-network sFC but increase between-network sFC, with the most prominent effect being attenuation of the default mode network (DMN) during the first half of a 20-min scan (i.e., during peak effects). SA reduced brainwide dFC but increased brainwide eFC, though only the former effect survived multiple comparison corrections. Finally, using connectome-based classification, most models trained on dFC network interactions could accurately classify the first half of SA scans. In contrast, few models trained on within- or between-network sFC and eFC performed above chance. Notably, models trained on within-DMN sFC and eFC performed better than models trained on other network interactions. This pattern of SA effects on human brain function is strikingly similar to that of other hallucinogens, necessitating studies of direct comparisons.

Rationale Salvinorin A is a kappa opioid agonist and the principal psychoactive constituent of the plant Salvia divinorum , which has increased in popularity as a recreational drug over the past decade. Few human studies have examined salvinorin A. Objective This double-blind, placebo-controlled study evaluated the dose-related effects of inhaled salvinorin A in individuals with histories of hallucinogen use. Methods Eight healthy hallucinogen-using adults inhaled up to 16 doses of salvinorin A (0.375–21 μg/kg) in ascending order. Physiological, behavioral, and subjective effects were assessed every 2 min for 60 min after administration. Qualitative subjective effects were assessed retrospectively via questionnaires at the end of sessions. Persisting effects were assessed 1 month later. Results Orderly dose-related effects peaked at 2 min and then rapidly dissipated, replicating previous findings. Subjective effects were intense, with maximal drug strength ratings or unresponsiveness frequently observed at high doses. Questionnaires assessing qualitative effects (Hallucinogen Rating Scale, Pharmacological Class Questionnaire) suggested some overlap with serotonergically mediated classic hallucinogens. Salvinorin A also produced dose-related dissociative effects and impairments in recall/recognition memory. At 1-month follow-up, there was no evidence of persisting adverse effects. Participants reported that salvinorin A effects were qualitatively different from other drugs. Conclusions Salvinorin A produces a unique profile of subjective and cognitive effects, including strong dissociative effects and memory impairment, which only partially overlap with classic hallucinogen effects. Along with nonhuman studies of salvinorin A, these results are important for understanding the neurobiology of the kappa opioid system and may ultimately have important therapeutic applications.

Abstract Background The mechanisms through which kappa opioid receptor (KOR) agonists induce psychotomimetic effects are largely unknown, although the modulation of this receptor has attracted attention for its clinical use. In this work, we characterize the neuropharmacological effects of salvinorin-A, a highly selective KOR agonist. Methods Changes in multimodal electroencephalography, single-photon emission computed tomography, and subjective effects following the acute administration of salvinorin-A are reported. The study included 2 sub-studies that employed a double-blind, crossover, randomized, placebo-controlled design. Results The electroencephalography measures showed a marked increase in delta and gamma waves and a decrease in alpha waves while subjects were under the effect of salvinorin-A. Regarding single-photon emission computed tomography measures, significant decreases in regional cerebral blood flow were detected in multiple regions of the frontal, temporal, parietal, and occipital cortices. Significant regional cerebral blood flow increases were observed in some regions of the medial temporal lobe, including the amygdala, the hippocampal gyrus, and the cerebellum. The pattern of subjective effects induced by salvinorin-A was similar to those observed in relation to other psychotomimetic drugs but with an evidently dissociative nature. No dysphoric effects were reported. Conclusion The salvinorin-A–mediated KOR agonism induced dramatic psychotomimetic effects along with a generalized decrease in cerebral blood flow and electric activity within the cerebral cortex.

Background:Salvinorin-A is a terpene found in the leaves of the plant Salvia divinorum. When administered to humans, salvinorin-A induces an intense but short-lasting modified state of awareness, sharing features with those induced by the classical serotonin-2A receptor agonist psychedelics. However, unlike substances such as psilocybin or mescaline, salvinorin-A shows agonist activity at the kappa-opioid receptor rather than at the serotonin-2A receptor. Here, we assessed the involvement of kappa-opioid receptor and serotonin-2A agonism in the subjective, cardiovascular, and neuroendocrine effects of salvinorin-A in humans.Methods:We conducted a placebo-controlled, randomized, double-blind study with 2 groups of 12 healthy volunteers with experience with psychedelic drugs. There were 4 experimental sessions. In group 1, participants received the following treatment combinations: placebo+placebo, placebo+salvinorin-A, naltrexone+placebo, and naltrexone+salvinorin-A. Naltrexone, a nonspecific opioid receptor antagonist, was administered at a dose of 50mg orally. In group 2, participants received the treatment combinations: placebo+placebo, placebo+salvinorin-A, ketanserin+placebo, and ketanserin+salvinorin-A. Ketanserin, a selective serotonin-2A antagonist, was administered at a dose of 40mg orally.Results:Inhalation of 1mg of vaporized salvinorin-A led to maximum plasma concentrations at 1 and 2 minutes after dosing. When administered alone, salvinorin-A severely reduced external sensory perception and induced intense visual and auditory modifications, increased systolic blood pressure, and cortisol and prolactin release. These effects were effectively blocked by naltrexone, but not by ketanserin.Conclusions:Results support kappa opioid receptor agonism as the mechanism of action underlying the subjective and physiological effects of salvinorin-A in humans and rule out the involvement of a serotonin-2A-mediated mechanism.

Rationale Salvia divinorum has been used for centuries, and nontraditional use in modern societies is increasing. Inebriation and aftereffects of use are poorly documented in the scientific literature. Objectives This double-blind, placebo-controlled, randomized study analyzed subjective experiences of salvinorin A (SA) inebriation and consequences of use after 8 weeks. Methods Thirty middle-aged, well-educated, hallucinogen-experienced participants smoked either 1,017 or 100 μg SA 2 weeks apart in counterbalanced order. Vital signs were recorded before and after inhalation. A researcher rated participants' behavior during sessions. Participants completed the Hallucinogen Rating Scale (HRS) assessing inebriation immediately after each session. Differences were analyzed between groups as functions of dose and time. After 8 weeks, participants were interviewed to determine reported consequences and aftereffects. Results Participants talked, laughed, and moved more often on an active dose. All six HRS clusters were significantly elevated on an active dose indicating hallucinogenic experiences. No significant adverse events were observed or reported by participants. Conclusions The present results indicate similarities as well as differences between the subjective effects of S. divinorum and other hallucinogens. As a selective kappa opioid receptor agonist, SA may be useful for expanding understanding of the psychopharmacology and psychology of hallucinogenic states beyond serotonergic mechanisms.

Rationale Salvinorin A (SA) is a highly selective kappa opioid receptor agonist and the putative psychoactive compound in Salvia divinorum (SD), an increasingly abused hallucinogenic plant. Objectives The objectives of this study were to characterize the physiological and subjective effects of SA versus placebo and measure drug and metabolite levels. Methods Sublingual SA doses up to 4 mg were administered in dimethyl sulfoxide/polyethylene glycol 400 solution to eight SD-experienced subjects using a placebo-controlled ascending-dose design. Results No dose of SA produced significantly greater physiological or subjective effects than placebo. Furthermore, effects did not resemble reported “typical” effects of smoked SD. SA was detectable in plasma and urine, but was, in most cases, below the reliable limit of quantification (0.5 ng/mL). Conclusions Our results suggest that the sublingual bioavailability of SA is low. Higher doses, alternate formulations, or alternate routes of administration will be necessary to study the effects of SA in humans.

Opioid receptors mediate the actions of endogenous and exogenous opioids on many physiological processes, including the regulation of pain, respiratory drive, mood, and—in the case of κ-opioid receptor (κ-OR)—dysphoria and psychotomimesis. Here we report the crystal structure of the human κ-OR in complex with the selective antagonist JDTic, arranged in parallel dimers, at 2.9 Å resolution. The structure reveals important features of the ligand-binding pocket that contribute to the high affinity and subtype selectivity of JDTic for the human κ-OR. Modelling of other important κ-OR-selective ligands, including the morphinan-derived antagonists norbinaltorphimine and 5′-guanidinonaltrindole, and the diterpene agonist salvinorin A analogue RB-64, reveals both common and distinct features for binding these diverse chemotypes. Analysis of site-directed mutagenesis and ligand structure–activity relationships confirms the interactions observed in the crystal structure, thereby providing a molecular explanation for κ-OR subtype selectivity, and essential insights for the design of compounds with new pharmacological properties targeting the human κ-OR. The crystal structure of the human κ-opioid receptor in complex with an antagonist, JDTic, is determined, with potential importance for the design of new therapeutic agents. Where opiates hit home Four papers in this issue of Nature present the long-awaited high-resolution crystal structures of the four known opioid receptors in ligand-bound conformations. These G-protein-coupled receptors are the targets of a broad range of drugs, including painkillers, antidepressants, anti-anxiety agents and anti-addiction medications. Brian Kobilka’s group reports the crystal structure of the µ-opioid receptor bound to a morphinan antagonist and the δ-opioid receptor bound to naltrindole. Raymond Stevens’ group reports on the κ-opioid receptor bound to the selective antagonist JDTic, and the nociceptin/orphanin FQ receptor bound to a peptide mimetic. In an associated News and Views, Marta Filizola and Lakshmi Devi discuss the implications of these landmark papers for research on the mechanisms underlying receptor function and drug development.

Salvia divinorum is a psychoactive plant presenting a complex pharmacological profile, attracting significant scientific interest due to its potential therapeutic applications and associated health risks. This review provides a comprehensive analysis of the toxic and therapeutic effects of S. divinorum, evaluating its potential medical applications while highlighting the risks associated with its consumption. Additionally, the review examines the plant’s recreational use, global consumption trends, and legal status. By synthesising current research, this article aims to clarify the implications of S. divinorum use and inform future studies on its pharmacological potential and regulatory considerations.

Three previously undescribed clerodane diterpenoids, including two cis-clerodanes, solidagolactone IX (1) and solidagoic acid K (2), and one trans-clerodane, solidagodiol (3), along with two known cis-clerodane diterpenoids, (−)-(5R,8R,9R,10S)-15,16-epoxy-ent-neo-cleroda-3,13,14-trien-18-ol (4) and solidagoic acid J (5), were isolated and comprehensively characterized from the ethanolic and ethyl acetate root extract of Solidago gigantea Ait. (giant goldenrod). Compound 4 has previously been reported from the roots of this species, whereas compound 5 was identified from the leaves of S. gigantea but not from the roots. The bioassay-guided isolation involved thin-layer chromatography–direct bioautography (TLC–DB) with a Bacillus subtilis antibacterial assay, preparative flash column chromatography, and TLC–mass spectrometry (MS). The chemical structures of the isolated compounds (1–5) were elucidated through extensive in-depth spectroscopic and spectrometric analyses, including one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy, high-resolution tandem mass spectrometry (HRMS/MS), and attenuated total reflectance Fourier-transform infrared (ATR–FTIR) spectroscopy. Their antimicrobial activities were evaluated using in vitro microdilution assays against B. subtilis and different plant pathogens. Compound 3 was the most active against the tested Gram-positive strains, exerting particularly potent effects against Clavibacter michiganensis with a minimal inhibitory concentration (MIC) value of 5.1 µM as well as B. subtilis and Curtobacterium flaccumfaciens pv. flaccumfaciens (MIC 21 µM for both). Compound 4 also strongly inhibited the growth of C. michiganensis (MIC 6.3 µM). Compounds 2, 4, and 5 displayed moderate to weak activity against B. subtilis and C. flaccumfaciens pv. flaccumfaciens with MIC values ranging from 100 to 402 µM. Rhodococcus fascians bacteria were moderately inhibited by compounds 3 (MIC 41 µM) and 4 (MIC 201 µM). Bactericidal activity was observed for compound 3 against C. michiganensis with a minimal bactericidal concentration (MBC) value of 83 µM. Compounds 2 and 3 demonstrated weak antifungal activity against Fusarium graminearum. Our findings underscore the value of bioassay-guided approaches in discovering previously undescribed bioactive compounds.

In this study, nine neo-clerodane-type diterpenoids (1–9) were isolated from the dichloromethane extract of Salvia guevarae Bedolla & Zamudio leaves. Compounds 1–6 were new natural products, and 7–9 were acetone artifacts. In addition, four neo-clerodanes diterpenoids (10–13) previously described from different sources and six triterpenoids—identified as 3β,20,25-trihydroxylupane, oleanolic acid, 3β-O-acetyl-oleanolic acid, ursolic acid, 3β-O-acetyl-betulinic acid, and 3β,28-O-diacetyl-betulin—were isolated. Additionally, five flavonoids were also isolated from the methanol extract: quercetin-3-O-β-xylopyranosyl-(1 → 2)-β-galactopyranoside, taxifolin-7-O-β-glucopyranoside, naringenin-7-O-β-glucopyranoside, a mixture of 2R and 2S eriodictyol-7-O-β-glucopyranoside, caffeic acid, the methyl ester of rosmarinic acid, and rosmarinic acid. The structure of the isolated compounds was established by spectroscopic means, mainly 1H and 13C NMR, including 1D and 2D homo- and heteronuclear experiments. The absolute configuration of 1 and 10 was ascertained via an X-ray analysis, and that of the other compounds via ECD. The antiproliferative activity of some diterpenoids was determined using the sulforhodamine B method, where guevarain B (2) and 6α-hydroxy-patagonol acetonide (7) showed moderate activity against the K562 line, with IC50 (μM) = 33.1 ± 1.3 and 39.8 ± 1.5, respectively. The NO inhibition in RAW 264.7 macrophage activity was also determined for some compounds, where 2-oxo-patagonal (6), 6α-hydroxy-patagonol acetonide (7), and 7α-acetoxy-ent-clerodan-3,13-dien-18,19:16,15-diolide (10) were proven to be active, with IC50 (μM) of 26.4 ± 0.4, 17.3 ± 0.5, and 13.7 ± 2.0, respectively. The chemotaxonomy of Salvia guevarae is also discussed.