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Pharmacokinetics and Pharmacodynamics of Salvinorin A and Salvia divinorum: Clinical and Forensic Aspects. Pharmaceuticals (Basel) 2021; 14:ph14020116. [PMID: 33546518 PMCID: PMC7913753 DOI: 10.3390/ph14020116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/26/2021] [Accepted: 01/29/2021] [Indexed: 01/13/2023] Open
Abstract
Salvia divinorum Epling and Játiva is a perennial mint from the Lamiaceae family, endemic to Mexico, predominantly from the state of Oaxaca. Due to its psychoactive properties, S. divinorum had been used for centuries by Mazatecans for divinatory, religious, and medicinal purposes. In recent years, its use for recreational purposes, especially among adolescents and young adults, has progressively increased. The main bioactive compound underlying the hallucinogenic effects, salvinorin A, is a non-nitrogenous diterpenoid with high affinity and selectivity for the κ-opioid receptor. The aim of this work is to comprehensively review and discuss the toxicokinetics and toxicodynamics of S. divinorum and salvinorin A, highlighting their psychological, physiological, and toxic effects. Potential therapeutic applications and forensic aspects are also covered in this review. The leaves of S. divinorum can be chewed, drunk as an infusion, smoked, or vaporised. Absorption of salvinorin A occurs through the oral mucosa or the respiratory tract, being rapidly broken down in the gastrointestinal system to its major inactive metabolite, salvinorin B, when swallowed. Salvinorin A is rapidly distributed, with accumulation in the brain, and quickly eliminated. Its pharmacokinetic parameters parallel well with the short-lived psychoactive and physiological effects. No reports on toxicity or serious adverse outcomes were found. A variety of therapeutic applications have been proposed for S. divinorum which includes the treatment of chronic pain, gastrointestinal and mood disorders, neurological diseases, and treatment of drug dependence. Notwithstanding, there is still limited knowledge regarding the pharmacology and toxicology features of S. divinorum and salvinorin A, and this is needed due to its widespread use. Additionally, the clinical acceptance of salvinorin A has been hampered, especially due to the psychotropic side effects and misuse, turning the scientific community to the development of analogues with better pharmacological profiles.
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Hernández-Alvarado RB, Madariaga-Mazón A, Ortega A, Martinez-Mayorga K. DARK Classics in Chemical Neuroscience: Salvinorin A. ACS Chem Neurosci 2020; 11:3979-3992. [PMID: 33164503 DOI: 10.1021/acschemneuro.0c00608] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Salvinorin A is the main bioactive compound in Salvia divinorum, an endemic plant with ancestral use by the inhabitants of the Mazateca mountain range (Sierra Mazateca) in Oaxaca, México. The main use of la pastora, as locally known, is in spiritual rites due to its extraordinary hallucinogenic effects. Being the first known nonalkaloidal opioid-mediated psychotropic molecule, salvinorin A set new research areas in neuroscience. The absence of a protonated amine group, common to all previously known opioids, results in a fast metabolism with the concomitant fast elimination and swift loss of activity. The worldwide spread and psychotropic effects of salvinorin A account for its misuse and classification as a drug of abuse. Consequently, salvinorin A and Salvia divinorum are now banned in many countries. Several synthetic efforts have been focused on the improvement of physicochemical and biological properties of salvinorin A: from total synthesis to hundreds of analogues. In this Review, we discuss the impact of salvinorin A in chemistry and neuroscience covering the historical relevance, isolation from natural sources, synthetic efforts, and pharmacological and safety profiles. Altogether, the chemistry behind and the taboo that encloses salvinorin A makes it one of the most exquisite naturally occurring drugs.
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Affiliation(s)
- R. Bruno Hernández-Alvarado
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510 México
| | - Abraham Madariaga-Mazón
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510 México
| | - Alfredo Ortega
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510 México
| | - Karina Martinez-Mayorga
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Ciudad de México, 04510 México
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Keasling AW, Pandey P, Doerksen RJ, Pedrino GR, Costa EA, da Cunha LC, Zjawiony JK, Fajemiroye JO. Salvindolin elicits opioid system-mediated antinociceptive and antidepressant-like activities. J Psychopharmacol 2019; 33:865-881. [PMID: 31192780 DOI: 10.1177/0269881119849821] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Salvinorin A is known as a highly selective kappa opioid receptor agonist with antinociceptive but mostly pro-depressive effects. AIMS In this article, we present its new semisynthetic analog with preferential mu opioid affinity, and promising antinociceptive, as well as antidepressant-like activities. METHODS Competitive binding studies were performed for salvindolin with kappa opioid and mu opioid. The mouse model of nociception (acetic-acid-induced writhing, formalin, and hot plate tests), depression (forced swim and tail suspension tests), and the open field test, were used to evaluate antinociceptive, antidepressant-like, and locomotion effects, respectively, of salvindolin. We built a 3-D molecular model of the kappa opioid receptor, using a mu opioid X-ray crystal structure as a template, and docked salvindolin into the two proteins. RESULTS/OUTCOMES Salvindolin showed affinity towards kappa opioid and mu opioid receptors but with 100-fold mu opioid preference. Tests of salvindolin in mice revealed good oral bioavailability, antinociceptive, and antidepressive-like effects, without locomotor incoordination. Docking of salvindolin showed strong interactions with the mu opioid receptor which matched well with experimental binding data. Salvindolin-induced behavioral changes in the hot plate and forced swim tests were attenuated by naloxone (nonselective opioid receptor antagonist) and/or naloxonazine (selective mu opioid receptor antagonist) but not by nor-binaltorphimine (selective kappa opioid receptor antagonist). In addition, WAY100635 (a selective serotonin 1A receptor antagonist) blocked the antidepressant-like effect of salvindolin. CONCLUSIONS/INTERPRETATION By simple chemical modification, we were able to modulate the pharmacological profile of salvinorin A, a highly selective kappa opioid receptor agonist, to salvindolin, a ligand with preferential mu opioid receptor affinity and activity on the serotonin 1A receptor. With its significant antinociceptive and antidepressive-like activities, salvindolin has the potential to be an analgesic and/or antidepressant drug candidate.
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Affiliation(s)
- Adam W Keasling
- 1 Department of BioMolecular Sciences, Division of Pharmacognosy, University of Mississippi, University, MS, USA.,2 Department of BioMolecular Sciences, Research Institute of Pharmaceutical Sciences, University of Mississippi, University, MS, USA
| | - Pankaj Pandey
- 3 Department of BioMolecular Sciences, Division of Medicinal Chemistry, University of Mississippi, University, MS, USA
| | - Robert J Doerksen
- 2 Department of BioMolecular Sciences, Research Institute of Pharmaceutical Sciences, University of Mississippi, University, MS, USA.,3 Department of BioMolecular Sciences, Division of Medicinal Chemistry, University of Mississippi, University, MS, USA
| | - Gustavo R Pedrino
- 4 Department of Physiology, Federal University of Goiás, Goiânia, Brazil
| | - Elson A Costa
- 5 Department of Pharmacology, Federal University of Goiás, Goiânia, Brazil
| | - Luiz C da Cunha
- 6 Center for Studies and Toxicological-Pharmacological Research, Federal University of Goiás, Goiânia, Brazil
| | - Jordan K Zjawiony
- 1 Department of BioMolecular Sciences, Division of Pharmacognosy, University of Mississippi, University, MS, USA.,2 Department of BioMolecular Sciences, Research Institute of Pharmaceutical Sciences, University of Mississippi, University, MS, USA
| | - James O Fajemiroye
- 5 Department of Pharmacology, Federal University of Goiás, Goiânia, Brazil.,6 Center for Studies and Toxicological-Pharmacological Research, Federal University of Goiás, Goiânia, Brazil.,7 Department of Pharmaceutical Science, University Center of Anápolis - Unievangélica, Anápolis, Brazil
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Kappa Opioid Receptor Agonist Mesyl Sal B Attenuates Behavioral Sensitization to Cocaine with Fewer Aversive Side-Effects than Salvinorin A in Rodents. Molecules 2018; 23:molecules23102602. [PMID: 30314288 PMCID: PMC6222496 DOI: 10.3390/molecules23102602] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/02/2018] [Accepted: 10/09/2018] [Indexed: 01/02/2023] Open
Abstract
The acute activation of kappa opioid receptors (KOPr) produces antinociceptive and anti-cocaine effects, however, their side-effects have limited further clinical development. Mesyl Sal B is a potent and selective KOPr analogue of Salvinorin A (Sal A), a psychoactive natural product isolated from the plant Salvia divinorum. We assessed the antinociceptive, anti-cocaine, and side-effects of Mesyl Sal B. The anti-cocaine effects are evaluated in cocaine-induced hyperactivity and behavioral sensitization to cocaine in male Sprague Dawley rats. Mesyl Sal B was assessed for anhedonia (conditioned taste aversion), aversion (conditioned place aversion), pro-depressive effects (forced swim test), anxiety (elevated plus maze) and learning and memory deficits (novel object recognition). In male B6.SJL mice, the antinociceptive effects were evaluated in warm-water (50 °C) tail withdrawal and intraplantar formaldehyde (2%) assays and the sedative effects measured with the rotarod performance task. Mesyl Sal B (0.3 mg/kg) attenuated cocaine-induced hyperactivity and behavioral sensitization to cocaine without modulating sucrose self-administration and without producing aversion, sedation, anxiety, or learning and memory impairment in rats. However, increased immobility was observed in the forced swim test indicating pro-depressive effects. Mesyl Sal B was not as potent as Sal A at reducing pain in the antinociceptive assays. In conclusion, Mesyl Sal B possesses anti-cocaine effects, is longer acting in vivo and has fewer side-effects when compared to Sal A, however, the antinociceptive effects are limited.
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Tryptophan-Containing Non-Cationizable Opioid Peptides - a new chemotype with unusual structure and in vivo activity. Future Med Chem 2017; 9:2099-2115. [PMID: 29130348 DOI: 10.4155/fmc-2017-0104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Recently, a new family of opioid peptides containing tryptophan came to the spotlight for the absence of the fundamental protonable tyramine 'message' pharmacophore. Structure-activity relationship investigations led to diverse compounds, characterized by different selectivity profiles and agonist or antagonist effects. Substitution at the indole of Trp clearly impacted peripheral/central antinociceptivity. These peculiarities prompted to gather all the compounds in a new class, and to coin the definition 'Tryptophan-Containing Non-Cationizable Opioid Peptides', in short 'TryCoNCOPs'. Molecular docking analysis suggested that the TryCoNCOPs can still interact with the receptors in an agonist-like fashion. However, most TryCoNCOPs showed significant differences between the in vitro and in vivo activities, suggesting that opioid activity may be elicited also via alternative mechanisms.
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Bartuzi D, Kaczor AA, Matosiuk D. Interplay between Two Allosteric Sites and Their Influence on Agonist Binding in Human μ Opioid Receptor. J Chem Inf Model 2016; 56:563-70. [PMID: 26863088 DOI: 10.1021/acs.jcim.5b00705] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Allostery is a widespread mechanism that allows for precise protein tuning. Its underlying mechanisms are elusive, particularly when there are multiple allosteric sites at the protein. This concerns also G-protein-coupled receptors (GPCRs), which are targets for a vast part of currently used drugs. To address this issue, we performed molecular dynamics simulations of a GPCR-human μ opioid receptor (MOR) in a native-like environment, with full agonist (R)-methadone, Na(+) ions, and a positive modulator BMS986122 in various configurations. We found that MOR's seventh transmembrane helix (TM VII) is central for allosteric signal transmission, and modulators affect its bending and rotation. The PAM stabilizes favorable agonist interactions, while Na(+) tends to disrupt agonist binding. We identified two residues involved in allosteric signal transmission: Trp 7.35 at the top and Tyr 7.53 at the bottom of TM VII.
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Affiliation(s)
- Damian Bartuzi
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modelling Lab, Medical University of Lublin , 4A Chodźki Str., PL20093 Lublin, Poland
| | - Agnieszka A Kaczor
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modelling Lab, Medical University of Lublin , 4A Chodźki Str., PL20093 Lublin, Poland.,University of Eastern Finland , School of Pharmacy, Yliopistonranta 1, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Dariusz Matosiuk
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modelling Lab, Medical University of Lublin , 4A Chodźki Str., PL20093 Lublin, Poland
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7
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Bartuzi D, Kaczor AA, Matosiuk D. Activation and Allosteric Modulation of Human μ Opioid Receptor in Molecular Dynamics. J Chem Inf Model 2015; 55:2421-34. [DOI: 10.1021/acs.jcim.5b00280] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Damian Bartuzi
- Department
of Synthesis and Chemical Technology of Pharmaceutical Substances
with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical
Analytics, Medical University of Lublin, 4A Chodźki St., PL-20093 Lublin, Poland
| | - Agnieszka A. Kaczor
- Department
of Synthesis and Chemical Technology of Pharmaceutical Substances
with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical
Analytics, Medical University of Lublin, 4A Chodźki St., PL-20093 Lublin, Poland
- School
of Pharmacy, University of Eastern Finland, Yliopistonranta 1, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Dariusz Matosiuk
- Department
of Synthesis and Chemical Technology of Pharmaceutical Substances
with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical
Analytics, Medical University of Lublin, 4A Chodźki St., PL-20093 Lublin, Poland
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8
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Riley AP, Groer CE, Young D, Ewald AW, Kivell BM, Prisinzano TE. Synthesis and κ-opioid receptor activity of furan-substituted salvinorin A analogues. J Med Chem 2014; 57:10464-75. [PMID: 25426797 PMCID: PMC4281103 DOI: 10.1021/jm501521d] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The neoclerodane diterpene salvinorin A, found in the leaves of Salvia divinorum, is a potent κ-opioid receptor agonist, making it an attractive scaffold for development into a treatment for substance abuse. Although several successful semisynthetic studies have been performed to elucidate structure-activity relationships, the lack of analogues with substitutions to the furan ring of salvinorin A has prevented a thorough understanding of its role in binding to the κ-opioid receptor. Herein we report the synthesis of several salvinorin A derivatives with modified furan rings. Evaluation of these compounds in a functional assay indicated that sterically less demanding substitutions are preferred, suggesting the furan ring is bound in a congested portion of the binding pocket. The most potent of the analogues successfully reduced drug-seeking behavior in an animal model of drug-relapse without producing the sedation observed with other κ-opioid agonists.
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Affiliation(s)
- Andrew P Riley
- Department of Chemistry and ‡Department of Medicinal Chemistry, School of Pharmacy, The University of Kansas , Lawrence, Kansas 66045, United States
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Weltrowska G, Lemieux C, Chung NN, Guo JJ, Wilkes BC, Schiller PW. 'Carba'-carfentanil (trans isomer): a μ opioid receptor (MOR) partial agonist with a distinct binding mode. Bioorg Med Chem 2014; 22:4581-6. [PMID: 25129170 DOI: 10.1016/j.bmc.2014.07.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 07/15/2014] [Accepted: 07/19/2014] [Indexed: 11/16/2022]
Abstract
There is strong evidence to indicate that a positively charged nitrogen of endogenous and exogenous opioid ligands forms a salt bridge with the Asp residue in the third transmembrane helix of opioid receptors. To further examine the role of this electrostatic interaction in opioid receptor binding and activation, we synthesized 'carba'-analogues of the highly potent μ opioid analgesic carfentanil (3), in which the piperidine nitrogen was replaced with a carbon. The resulting trans isomer (8b) showed reduced, but still significant MOR binding affinity (Ki(μ)=95.2nM) with no MOR versus DOR binding selectivity and was a MOR partial agonist. The cis isomer (8a) was essentially inactive. A MOR docking study indicated that 8b bound to the same binding pocket as parent 3, but its binding mode was somewhat different. A re-evaluation of the uncharged morphine derivative N-formylnormorphine (9) indicated that it was a weak MOR antagonist showing no preference for MOR over KOR. Taken together, the results indicate that deletion of the positively charged nitrogen in μ opioid analgesics reduces MOR binding affinity by 2-3 orders of magnitude and may have pronounced effects on the intrinsic efficacy and on the opioid receptor selectivity profile.
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Affiliation(s)
- Grazyna Weltrowska
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
| | - Carole Lemieux
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
| | - Nga N Chung
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
| | - Jason J Guo
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Brian C Wilkes
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
| | - Peter W Schiller
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada; Department of Pharmacology, Université de Montréal, Montreal, QC H3C 3J7, Canada.
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10
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Simonson B, Morani AS, Ewald AWM, Walker L, Kumar N, Simpson D, Miller JH, Prisinzano TE, Kivell BM. Pharmacology and anti-addiction effects of the novel κ opioid receptor agonist Mesyl Sal B, a potent and long-acting analogue of salvinorin A. Br J Pharmacol 2014; 172:515-31. [PMID: 24641310 DOI: 10.1111/bph.12692] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 03/09/2014] [Accepted: 03/11/2014] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Acute activation of κ opioid (KOP) receptors results in anticocaine-like effects, but adverse effects, such as dysphoria, aversion, sedation and depression, limit their clinical development. Salvinorin A, isolated from the plant Salvia divinorum, and its semi-synthetic analogues have been shown to have potent KOP receptor agonist activity and may induce a unique response with similar anticocaine addiction effects as the classic KOP receptor agonists, but with a different side effect profile. EXPERIMENTAL APPROACH We evaluated the duration of effects of Mesyl Sal B in vivo utilizing antinociception assays and screened for cocaine-prime induced cocaine-seeking behaviour in self-administering rats to predict anti-addiction effects. Cellular transporter uptake assays and in vitro voltammetry were used to assess modulation of dopamine transporter (DAT) function and to investigate transporter trafficking and kinase signalling pathways modulated by KOP receptor agonists. KEY RESULTS Mesyl Sal B had a longer duration of action than SalA, had anti-addiction properties and increased DAT function in vitro in a KOP receptor-dependent and Pertussis toxin-sensitive manner. These effects on DAT function required ERK1/2 activation. We identified differences between Mesyl Sal B and SalA, with Mesyl Sal B increasing the Vmax of dopamine uptake without altering cell-surface expression of DAT. CONCLUSIONS AND IMPLICATIONS SalA analogues, such as Mesyl Sal B, have potential for development as anticocaine agents. Further tests are warranted to elucidate the mechanisms by which the novel salvinorin-based neoclerodane diterpene KOP receptor ligands produce both anti-addiction and adverse side effects. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- B Simonson
- School of Biological Science, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
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Rico-Martínez M, Medina FG, Marrero JG, Osegueda-Robles S. Biotransformation of diterpenes. RSC Adv 2014. [DOI: 10.1039/c3ra45146a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Structural modification of the diterpenes to enhance their pharmaceutical relevance can be efficiently carried out by the application of biotransformational under mild reaction.
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Affiliation(s)
- María Rico-Martínez
- Instituto Politécnico Nacional
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato
- C.P. 36275 Silao de la Victoria, Mexico
| | - Fernanda G. Medina
- Instituto Politécnico Nacional
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato
- C.P. 36275 Silao de la Victoria, Mexico
| | - Joaquín G. Marrero
- Instituto Politécnico Nacional
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato
- C.P. 36275 Silao de la Victoria, Mexico
| | - Soraya Osegueda-Robles
- Instituto Politécnico Nacional
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato
- C.P. 36275 Silao de la Victoria, Mexico
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Munro TA, Xu W, Ho DM, Liu-Chen LY, Cohen BM. Studies toward bivalent κ opioids derived from salvinorin A: heteromethylation of the furan ring reduces affinity. Beilstein J Org Chem 2013; 9:2916-24. [PMID: 24454571 PMCID: PMC3896271 DOI: 10.3762/bjoc.9.328] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 11/21/2013] [Indexed: 11/23/2022] Open
Abstract
The recent crystal structure of the κ-opioid receptor (κ-OR) revealed, unexpectedly, that the antagonist JDTic is a bivalent ligand: in addition to the orthosteric pocket occupied by morphinans, JDTic also occupies a distinct (allotopic) pocket. Mutagenesis data suggest that salvinorin A (1) also binds to this allotopic pocket, adjacent to the aspartate residue that anchors the basic nitrogen atom of classical opiates (Asp138). It has been suggested that an H-bond donor appended to 1 might interact with Asp138, increasing affinity. Such a bivalent ligand might also possess altered functional selectivity. Based on modeling and known N-furanylmethyl opioid antagonists, we appended H-bond donors to the furan ring of 1. (Dimethylamino)methyl groups at C-15 or C-16 abolished affinity for κ-OR. Hydroxymethylation at C-16 was tolerated, but 15,16-bis-hydroxymethylation was not. Since allosteric modulators may go undetected in binding assays, we also tested these and other low-affinity derivatives of 1 for allosteric modulation of dynorphin A in the [35S]GTPγS assay. No modulation was detected. As an alternative attachment point for bivalent derivatives, we prepared the 2-(hydroxyethoxy)methyl ether, which retained high affinity for κ-OR. We discuss alternative design strategies for linked, fused or merged bivalent derivatives of 1.
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Affiliation(s)
- Thomas A Munro
- McLean Hospital, Belmont, MA 02478, USA and Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA ; School of Chemistry and Bio21 Institute, University of Melbourne, Parkville 3010, Australia
| | - Wei Xu
- Center for Substance Abuse Research and Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Douglas M Ho
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge MA 02138, USA
| | - Lee-Yuan Liu-Chen
- Center for Substance Abuse Research and Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Bruce M Cohen
- McLean Hospital, Belmont, MA 02478, USA and Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA
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Vardy E, Mosier PD, Frankowski KJ, Wu H, Katritch V, Westkaemper RB, Aubé J, Stevens RC, Roth BL. Chemotype-selective modes of action of κ-opioid receptor agonists. J Biol Chem 2013; 288:34470-83. [PMID: 24121503 DOI: 10.1074/jbc.m113.515668] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The crystal structures of opioid receptors provide a novel platform for inquiry into opioid receptor function. The molecular determinants for activation of the κ-opioid receptor (KOR) were studied using a combination of agonist docking, functional assays, and site-directed mutagenesis. Eighteen positions in the putative agonist binding site of KOR were selected and evaluated for their effects on receptor binding and activation by ligands representing four distinct chemotypes: the peptide dynorphin A(1-17), the arylacetamide U-69593, and the non-charged ligands salvinorin A and the octahydroisoquinolinone carboxamide 1xx. Minimally biased docking of the tested ligands into the antagonist-bound KOR structure generated distinct binding modes, which were then evaluated biochemically and pharmacologically. Our analysis identified two types of mutations: those that affect receptor function primarily via ligand binding and those that primarily affect function. The shared and differential mechanisms of agonist binding and activation in KOR are further discussed. Usually, mutations affecting function more than binding were located at the periphery of the binding site and did not interact strongly with the various ligands. Analysis of the crystal structure along with the present results provide fundamental insights into the activation mechanism of the KOR and suggest that "functional" residues, along with water molecules detected in the crystal structure, may be directly involved in transduction of the agonist binding event into structural changes at the conserved rotamer switches, thus leading to receptor activation.
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Affiliation(s)
- Eyal Vardy
- From the Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
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De Marco R, Tolomelli A, Spampinato S, Bedini A, Gentilucci L. Opioid activity profiles of oversimplified peptides lacking in the protonable N-terminus. J Med Chem 2012; 55:10292-6. [PMID: 22995061 DOI: 10.1021/jm301213s] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recently, we described cyclopeptide opioid agonists containing the d-Trp-Phe sequence. To expand the scope of this atypical pharmacophore, we tested the activity profiles of the linear peptides Ac-Xaa-Phe-Yaa (Xaa = l/d-Trp, d-His/Lys/Arg; Yaa = H, GlyNH(2)). Ac-d-Trp-PheNH(2) appeared to be the minimal binding sequence, while Ac-d-Trp-Phe-GlyNH(2) emerged as the first noncationizable short peptide (partial) agonist with high μ-opioid receptor affinity and selectivity. Conformational analysis suggested that 5 adopts in solution a β-turn conformation.
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Affiliation(s)
- Rossella De Marco
- Department of Chemistry "G. Ciamician", University of Bologna, Via Selmi 2, 40126 Bologna, Italy
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15
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Congreve M, Langmead CJ, Mason JS, Marshall FH. Progress in structure based drug design for G protein-coupled receptors. J Med Chem 2011; 54:4283-311. [PMID: 21615150 PMCID: PMC3308205 DOI: 10.1021/jm200371q] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Indexed: 12/12/2022]
Affiliation(s)
- Miles Congreve
- Heptares Therapeutics Limited, BioPark, Welwyn Garden City, Hertfordshire, UK.
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16
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Gentilucci L, Tolomelli A, De Marco R, Spampinato S, Bedini A, Artali R. The Inverse Type II β-Turn on D-Trp-Phe, a Pharmacophoric Motif for MOR Agonists. ChemMedChem 2011; 6:1640-53. [DOI: 10.1002/cmdc.201100169] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 05/19/2011] [Indexed: 11/12/2022]
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17
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Shim J, Coop A, MacKerell AD. Consensus 3D model of μ-opioid receptor ligand efficacy based on a quantitative Conformationally Sampled Pharmacophore. J Phys Chem B 2011; 115:7487-96. [PMID: 21563754 PMCID: PMC3113728 DOI: 10.1021/jp202542g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Despite being studied for over 30 years, a consensus structure-activity relationship (SAR) that encompasses the full range peptidic and nonpeptidic μ-opioid receptor ligands is still not available. To achieve a consensus SAR the Conformationally Sampled Pharmacophore (CSP) method was applied to develop a predictive model of the efficacy of μ-opioid receptor ligands. Emphasis was placed on predicting the efficacy of a wide range of agonists, partial agonists, and antagonists as well as understanding their mode of interaction with the receptor. Inclusion of all accessible conformations of each ligand, a central feature of the CSP method, enabled structural features between diverse μ-opioid receptor ligands that dictate efficacy to be identified. The models were validated against a diverse collection of peptidic and nonpeptidic ligands, including benzomorphans, fentanyl (4-anilinopiperidine), methadone (3,3-diphenylpropylamines), etonitazene (benzimidazole derivatives), funaltrexamine (C6-substituted 4,5-epoxymorphinan), and herkinorin. The model predicts (1) that interactions of ligands with the B site, as with the 19-alkyl substituents of oripavines, modulate the extent of agonism; (2) that agonists with long N-substituents, as with fentanyl and N-phenethylnormorphine, can bind in an orientation such that the N substitutent interacts with the B site that also allows the basic N-receptor Asp interaction essential for agonism; and (3) that the μ agonist herkinorin, that lacks a basic nitrogen, binds to the receptor in a manner similar to the traditional opioids via interactions mediated by water or a ion. Importantly, the proposed CSP model can be reconciled with previously published SAR models for the μ receptor.
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Affiliation(s)
- Jihyun Shim
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, United States
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18
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Lozama A, Cunningham CW, Caspers MJ, Douglas JT, Dersch CM, Rothman RB, Prisinzano TE. Opioid receptor probes derived from cycloaddition of the hallucinogen natural product salvinorin A. JOURNAL OF NATURAL PRODUCTS 2011; 74:718-726. [PMID: 21338114 PMCID: PMC3081938 DOI: 10.1021/np1007872] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
As part of our continuing efforts toward more fully understanding the structure-activity relationships of the neoclerodane diterpene salvinorin A, we report the synthesis and biological characterization of unique cycloadducts through [4+2] Diels-Alder cycloaddition. Microwave-assisted methods were developed and successfully employed, aiding in functionalizing the chemically sensitive salvinorin A scaffold. This demonstrates the first reported results for both cycloaddition of the furan ring and functionalization via microwave-assisted methodology of the salvinorin A skeleton. The cycloadducts yielded herein introduce electron-withdrawing substituents and bulky aromatic groups into the C-12 position. Kappa opioid (KOP) receptor space was explored through aromatization of the bent oxanorbornadiene system possessed by the cycloadducts to a planar phenyl ring system. Although dimethyl- and diethylcarboxylate analogues 5 and 6 retain some affinity and selectivity for KOP receptors and are full agonists, their aromatized counterparts 13 and 14 have reduced affinity for KOP receptors. The methods developed herein signify a novel approach toward rapidly probing the structure-activity relationships of furan-containing natural products.
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Affiliation(s)
| | | | | | | | | | | | - Thomas E. Prisinzano
- To whom correspondence should be addressed: Tel: (785) 864-3267. Fax: (785) 864-5326.
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19
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Lanfranchi DA, Bour C, Hanquet G. Enantioselective Access to Key Intermediates for Salvinorin A and Analogues. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100207] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Cunningham CW, Rothman RB, Prisinzano TE. Neuropharmacology of the naturally occurring kappa-opioid hallucinogen salvinorin A. Pharmacol Rev 2011; 63:316-47. [PMID: 21444610 DOI: 10.1124/pr.110.003244] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Salvia divinorum is a perennial sage native to Oaxaca, Mexico, that has been used traditionally in divination rituals and as a treatment for the "semimagical" disease panzón de borrego. Because of the intense "out-of-body" experiences reported after inhalation of the pyrolized smoke, S. divinorum has been gaining popularity as a recreational hallucinogen, and the United States and several other countries have regulated its use. Early studies isolated the neoclerodane diterpene salvinorin A as the principal psychoactive constituent responsible for these hallucinogenic effects. Since the finding that salvinorin A exerts its potent psychotropic actions through the activation of KOP receptors, there has been much interest in elucidating the underlying mechanisms behind its effects. These effects are particularly remarkable, because 1) salvinorin A is the first reported non-nitrogenous opioid receptor agonist, and 2) its effects are not mediated by the 5-HT(2A) receptor, the classic target of hallucinogens such as lysergic acid diethylamide and mescaline. Rigorous investigation into the structural features of salvinorin A responsible for opioid receptor affinity and selectivity has produced numerous receptor probes, affinity labels, and tools for evaluating the biological processes responsible for its observed psychological effects. Salvinorin A has therapeutic potential as a treatment for pain, mood and personality disorders, substance abuse, and gastrointestinal disturbances, and suggests that nonalkaloids are potential scaffolds for drug development for aminergic G-protein coupled receptors.
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21
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Weltrowska G, Chung NN, Lemieux C, Guo J, Lu Y, Wilkes BC, Schiller PW. "Carba"-analogues of fentanyl are opioid receptor agonists. J Med Chem 2010; 53:2875-81. [PMID: 20218625 DOI: 10.1021/jm9019068] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is evidence to indicate that the Asp residue in the third transmembrane helix (TMH) of opioid receptors forms a salt bridge with the positively charged nitrogen of endogenous and exogenous opioid ligands. To further examine the role of this electrostatic interaction in receptor binding and activation, we synthesized "carba"-analogues of a published fentanyl analogue containing a 3-(guanidinomethyl)-benzyl group in place of the phenyl moiety attached to the ethylamido group (C. Dardonville et al., Bioorg. Med. Chem. 2006, 14, 6570-6580 (1)), in which the piperidine ring nitrogen was replaced with a carbon. As expected, the resulting cis and trans isomers (8a and 8b) showed reduced mu and kappa opioid receptor binding affinities as compared to 1 but, surprisingly, retained opioid full agonist activity with about half the potency of leucine-enkephalin in the guinea pig ileum assay. In conjunction with performed receptor docking studies, these results indicate that the electrostatic interaction of the protonated nitrogen in the piperidine ring of fentanyl analogues with the Asp residue in the third TMH is not a conditio sine qua non for opioid receptor activation.
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Affiliation(s)
- Grazyna Weltrowska
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, Quebec, Canada H2W 1R7
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22
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McGovern DL, Mosier PD, Roth BL, Westkaemper RB. CoMFA analyses of C-2 position salvinorin A analogs at the kappa-opioid receptor provides insights into epimer selectivity. J Mol Graph Model 2010; 28:612-25. [PMID: 20083418 DOI: 10.1016/j.jmgm.2009.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 11/20/2009] [Accepted: 12/21/2009] [Indexed: 12/15/2022]
Abstract
The highly potent and kappa-opioid (KOP) receptor-selective hallucinogen Salvinorin A and selected analogs have been analyzed using the 3D quantitative structure-affinity relationship technique Comparative Molecular Field Analysis (CoMFA) in an effort to derive a statistically significant and predictive model of salvinorin affinity at the KOP receptor and to provide additional statistical support for the validity of previously proposed structure-based interaction models. Two CoMFA models of Salvinorin A analogs substituted at the C-2 position are presented. Separate models were developed based on the radioligand used in the kappa-opioid binding assay, [(3)H]diprenorphine or [(125)I]6 beta-iodo-3,14-dihydroxy-17-cyclopropylmethyl-4,5 alpha-epoxymorphinan ([(125)I]IOXY). For each dataset, three methods of alignment were employed: a receptor-docked alignment derived from the structure-based docking algorithm GOLD, another from the ligand-based alignment algorithm FlexS, and a rigid realignment of the poses from the receptor-docked alignment. The receptor-docked alignment produced statistically superior results compared to either the FlexS alignment or the realignment in both datasets. The [(125)I]IOXY set (Model 1) and [(3)H]diprenorphine set (Model 2) gave q(2) values of 0.592 and 0.620, respectively, using the receptor-docked alignment, and both models produced similar CoMFA contour maps that reflected the stereoelectronic features of the receptor model from which they were derived. Each model gave significantly predictive CoMFA statistics (Model 1 PSET r(2)=0.833; Model 2 PSET r(2)=0.813). Based on the CoMFA contour maps, a binding mode was proposed for amine-containing Salvinorin A analogs that provides a rationale for the observation that the beta-epimers (R-configuration) of protonated amines at the C-2 position have a higher affinity than the corresponding alpha-epimers (S-configuration).
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Affiliation(s)
- Donna L McGovern
- Department of Medicinal Chemistry, P.O. Box 980540, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298-0540, USA
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23
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Abstract
The isolation, structures and biological activity of the neoclerodane and other natural products obtained from the Mexican hallucinogenic sage, Salvia divinorum are reviewed.
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24
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Yamaotsu N, Hirono S. 3D-Pharmacophore Identification for κ-Opioid Agonists Using Ligand-Based Drug-Design Techniques. Top Curr Chem (Cham) 2010; 299:277-307. [DOI: 10.1007/128_2010_84] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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25
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Abstract
This paper is the 31st consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2008 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd, Flushing, NY 11367, United States.
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26
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Seeman P, Guan HC, Hirbec H. Dopamine D2High receptors stimulated by phencyclidines, lysergic acid diethylamide, salvinorin A, and modafinil. Synapse 2009; 63:698-704. [PMID: 19391150 DOI: 10.1002/syn.20647] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Although it is commonly stated that phencyclidine is an antagonist at ionotropic glutamate receptors, there has been little measure of its potency on other receptors in brain tissue. Although we previously reported that phencyclidine stimulated cloned-dopamine D2Long and D2Short receptors, others reported that phencyclidine did not stimulate D2 receptors in homogenates of rat brain striatum. This study, therefore, examined whether phencyclidine and other hallucinogens and psychostimulants could stimulate the incorporation of [(35)S]GTP-gamma-S into D2 receptors in homogenates of rat brain striatum, using the same conditions as previously used to study the cloned D2 receptors. Using 10 microM dopamine to define 100% stimulation, phencyclidine elicited a maximum incorporation of 46% in rat striata, with a half-maximum concentration of 70 nM for phencyclidine, when compared with 80 nM for dopamine, 89 nM for salvinorin A (48 nM for D2Long), 105 nM for lysergic acid diethylamide (LSD), 120 nM for R-modafinil, 710 nM for dizocilpine, 1030 nM for ketamine, and >10,000 nM for S-modafinil. These compounds also inhibited the binding of the D2-selective ligand [(3)H]domperidone. The incorporation was inhibited by the presence of 200 microM guanylylimidodiphosphate and also by D2 blockade, using 10 microM S-sulpiride, but not by D1 blockade with 10 microM SCH23390. Hypertonic buffer containing 150 mM NaCl inhibited the stimulation by phencyclidine, which may explain negative results by others. It is concluded that phencyclidine and other psychostimulants and hallucinogens can stimulate dopamine D2 receptors at concentrations related to their behavioral actions.
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, Medical Science Building, University of Toronto, Toronto, Ontario, Canada.
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27
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Simpson DS, Lovell KM, Lozama A, Han N, Day VW, Dersch CM, Rothman RB, Prisinzano TE. Synthetic studies of neoclerodane diterpenes from Salvia divinorum: role of the furan in affinity for opioid receptors. Org Biomol Chem 2009; 7:3748-56. [PMID: 19707679 DOI: 10.1039/b905148a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Further synthetic modification of the furan ring of salvinorin A (1), the major active component of Salvia divinorum, has resulted in novel neoclerodane diterpenes with opioid receptor affinity and activity. A computational study has predicted 1 to be a reproductive toxicant in mammals and is suggestive that use of 1 may be associated with adverse effects. We report in this study that piperidine 21 and thiomorpholine 23 have been identified as selective partial agonists at kappa opioid receptors. This indicates that additional structural modifications of 1 may provide ligands with good selectivity for opioid receptors but with reduced potential for toxicity.
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Affiliation(s)
- Denise S Simpson
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS 66045-7582, USA
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28
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Abstract
Background: Traditional and current opioid pharmacology is fundamentally based on interactions between opioid receptors and compounds isolated from natural sources. Adverse effects associated with opioids have led to the search for compounds with diminished side effects. Discussion: Recent discoveries of non-nitrogenous and structurally diverse alkaloids as novel opioid ligands have led to renewed interest in the development of novel chemotypes for opioid receptors. Conclusion: The strong history of natural products as opioid receptor ligands suggests that nature is one of the most promising for the identification of novel opioids. This review highlights the vast potential of investigating natural products as novel probes of opioid receptors.
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29
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Beerepoot P, Lam V, Luu A, Tsoi B, Siebert D, Szechtman H. Effects of salvinorin A on locomotor sensitization to D2/D3 dopamine agonist quinpirole. Neurosci Lett 2009; 446:101-4. [PMID: 18824069 DOI: 10.1016/j.neulet.2008.09.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 09/16/2008] [Accepted: 09/16/2008] [Indexed: 11/26/2022]
Abstract
Locomotor sensitization induced by the dopamine agonist quinpirole can be potentiated by co-treatment with the synthetic kappa opioid agonist U69593. The identification of salvinorin A, an active component of the psychotropic sage Salvia divinorum, as a structurally different agonist of kappa-opioid receptors raised the question of whether this compound would similarly potentiate sensitization to quinpirole. Rats were co-treated with 0.5 mg/kg quinpirole and either salvinorin A (0.04, 0.4 or 2.0 mg/kg) or U69593 (0.3 mg/kg). Control groups were co-treated with vehicle and saline, vehicle and quinpirole (0.5 mg/kg), or saline and salvinorin A (0.4 mg/kg). Rats were injected biweekly for a total of 10 injections and locomotor activity measured after each treatment. Results showed that the highest dose of salvinorin A potentiated sensitization to quinpirole as did U69593, the middle salvinorin A dose had no effect on quinpirole sensitization, and the lowest dose of salvinorin A attenuated sensitization to quinpirole. These findings indicate that structural differences between salvinorin A and U69593 do not affect the potentiation of quinpirole sensitization. Moreover, the opposite effects of high and low salvinorin A doses suggest that salvinorin A can produce bidirectional modulation of sensitization to dopamine agonists.
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Affiliation(s)
- Pieter Beerepoot
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Canada
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30
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Eckenhoff R, Zheng W, Kelz M. From anesthetic mechanisms research to drug discovery. Clin Pharmacol Ther 2008; 84:144-8. [PMID: 18449184 DOI: 10.1038/clpt.2008.77] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ability to render patients insensible and amnesic to remarkably invasive procedures that are uncomfortable to watch, let alone experience, has been rightly designated as one of the greatest medical discoveries of all time. General anesthesia, introduced formally in the mid-nineteenth century, is now delivered to approximately 40 million patients every year in the United States alone. Given its central role in health care, it is indeed extraordinary how poorly we understand anesthesia and anesthetics. In fact, definitions are at best operational and convey little understanding of the underlying neurobiology, while the hypothetical mechanisms are surprisingly superficial. Worse, there is growing concern that the anesthetic drugs in current use, especially the inhaled anesthetics, have durable adverse effects on cognition.
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Affiliation(s)
- Rg Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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