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Kellogg GE, Cen Y, Dukat M, Ellis KC, Guo Y, Li J, May AE, Safo MK, Zhang S, Zhang Y, Desai UR. Merging cultures and disciplines to create a drug discovery ecosystem at Virginia commonwealth university: Medicinal chemistry, structural biology, molecular and behavioral pharmacology and computational chemistry. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2023; 28:255-269. [PMID: 36863508 PMCID: PMC10619687 DOI: 10.1016/j.slasd.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/10/2023] [Accepted: 02/21/2023] [Indexed: 03/04/2023]
Abstract
The Department of Medicinal Chemistry, together with the Institute for Structural Biology, Drug Discovery and Development, at Virginia Commonwealth University (VCU) has evolved, organically with quite a bit of bootstrapping, into a unique drug discovery ecosystem in response to the environment and culture of the university and the wider research enterprise. Each faculty member that joined the department and/or institute added a layer of expertise, technology and most importantly, innovation, that fertilized numerous collaborations within the University and with outside partners. Despite moderate institutional support with respect to a typical drug discovery enterprise, the VCU drug discovery ecosystem has built and maintained an impressive array of facilities and instrumentation for drug synthesis, drug characterization, biomolecular structural analysis and biophysical analysis, and pharmacological studies. Altogether, this ecosystem has had major impacts on numerous therapeutic areas, such as neurology, psychiatry, drugs of abuse, cancer, sickle cell disease, coagulopathy, inflammation, aging disorders and others. Novel tools and strategies for drug discovery, design and development have been developed at VCU in the last five decades; e.g., fundamental rational structure-activity relationship (SAR)-based drug design, structure-based drug design, orthosteric and allosteric drug design, design of multi-functional agents towards polypharmacy outcomes, principles on designing glycosaminoglycans as drugs, and computational tools and algorithms for quantitative SAR (QSAR) and understanding the roles of water and the hydrophobic effect.
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Affiliation(s)
- Glen E Kellogg
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA.
| | - Yana Cen
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Malgorzata Dukat
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Keith C Ellis
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Youzhong Guo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Jiong Li
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Aaron E May
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Martin K Safo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Shijun Zhang
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Yan Zhang
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Umesh R Desai
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA.
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Martín-López M, Muela AT, Cavas M, Navarro JF. Effects of para-methoxyamphetamine (PMA) on agonistic encounters between male mice. Pharmacol Biochem Behav 2018; 167:9-16. [PMID: 29453997 DOI: 10.1016/j.pbb.2018.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 11/30/2022]
Abstract
Para-methoxyamphetamine (PMA) is a synthetic drug chemically similar to the recreational drug 3,4-methylenedioxy-methamphetamine (MDMA or "ecstasy") and often replaces MDMA in tablets that show an "ecstasy" logo. PMA displays a higher toxic potential than MDMA, but the behavioral profile of PMA has been scarcely studied in animal models. Here we evaluated the effects of PMA (2, 4, 8, and 12 mg/kg, i.p.) on agonist encounters between male mice using an ethopharmacological approach, the isolation-induced aggression model. Likewise, since PMA and MDMA share common mechanisms of action, we compared the behavioral profile of PMA with that induced by MDMA (8 mg/kg, i.p.) which behavioral effects in this model are well characterized. Individually housed mice were exposed to anosmic standard opponents 30 min after drug administration. The encounters were videotaped and evaluated using an ethologically based analysis. PMA (all doses) significantly reduced offensive behaviors (threat and attack), however, a detailed behavioral analysis suggests that the observed antiaggressive effect seems to be unspecific, showing a complex dose-dependent behavioral profile. Thus, antiaggresive actions observed after the administration of the lowest dose were accompanied by increases in social investigation, avoidance/flee behaviors and non-social explorations, together with a reduction of digging behavior. This pattern reflects both approach-contact behaviors and avoidance-flee behaviors. From 4 mg/kg to 12 mg/kg, the increase in social investigation previously observed disappears, and there is a slight increase in immobility, together with a different behavioral pattern that suggests anxiogenic effects of PMA, similar to those reported after the administration of MDMA. The higher doses of PMA exhibit a behavioral profile very similar to that observed in animals treated with MDMA, with the exception of the immobility produced by PMA. These findings show for the first time the non-specific antiaggressive profile of PMA in the model of aggression induced by isolation in male mice.
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Affiliation(s)
- Mercedes Martín-López
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain.
| | - Ana T Muela
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain
| | - María Cavas
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain
| | - José Francisco Navarro
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain
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Simmler LD, Liechti ME. Pharmacology of MDMA- and Amphetamine-Like New Psychoactive Substances. Handb Exp Pharmacol 2018; 252:143-164. [PMID: 29633178 DOI: 10.1007/164_2018_113] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
New psychoactive substances (NPS) with amphetamine-, aminoindan-, and benzofuran basic chemical structures have recently emerged for recreational drug use. Detailed information about their psychotropic effects and health risks is often limited. At the same time, it emerged that the pharmacological profiles of these NPS resemble those of amphetamine or 3,4-methylenedioxymethamphetamine (MDMA). Amphetamine-like NPS induce psychostimulation and euphoria mediated predominantly by norepinephrine (NE) and dopamine (DA) transporter (NET and DAT) inhibition and transporter-mediated release of NE and DA, thus showing a more catecholamine-selective profile. MDMA-like NPS frequently induce well-being, empathy, and prosocial effects and have only moderate psychostimulant properties. These MDMA-like substances primarily act by inhibiting the serotonin (5-HT) transporter (SERT) and NET, also inducing 5-HT and NE release. Monoamine receptor interactions vary considerably among amphetamine- and MDMA-like NPS. Clinically, amphetamine- and MDMA-like NPS can induce sympathomimetic toxicity. The aim of this chapter is to review the state of knowledge regarding these substances with a focus on the description of the in vitro pharmacology of selected amphetamine- and MDMA-like NPS. In addition, it is aimed to provide links between pharmacological profiles and in vivo effects and toxicity, which leads to the conclusion that abuse liability for amphetamine-like NPS may be higher than for MDMA-like NPS, but that the risk for developing the life-threatening serotonin syndrome may be increased for MDMA-like NPS.
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Affiliation(s)
- Linda D Simmler
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland.
| | - Matthias E Liechti
- Division of Clinical Pharmacology and Toxicology, University Hospital Basel, Basel, Switzerland.
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Tyrkkö E, Andersson M, Kronstrand R. The Toxicology of New Psychoactive Substances: Synthetic Cathinones and Phenylethylamines. Ther Drug Monit 2016; 38:190-216. [PMID: 26587869 DOI: 10.1097/ftd.0000000000000263] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND New psychoactive substances (NPSs) are substitutes for classical drugs of abuse and there are now compounds available from all groups of classical drugs of abuse. During 2014, the number of synthetic cathinones increased dramatically and, together with phenylethylamines, they dominate the NPS markets in the European Union. In total, 31 cathinones and 9 phenylethylamines were encountered in 2014. The aim of this article was to summarize the existing knowledge about the basic pharmacology, metabolism, and human toxicology of relevant synthetic cathinones and phenylethylamines. Compared with existing reviews, we have also compiled the existing case reports from both fatal and nonfatal intoxications. METHODS We performed a comprehensive literature search using bibliographic databases PubMed and Web of Science, complemented with Google Scholar. The focus of the literature search was on original articles, case reports, and previously published review articles published in 2014 or earlier. RESULTS The rapid increase of NPSs is a growing concern and sets new challenges not only for societies in drug prevention and legislation but also in clinical and forensic toxicology. In vivo and in vitro studies have demonstrated that the pharmacodynamic profile of cathinones is similar to that of other psychomotor stimulants. Metabolism studies show that cathinones and phenylethylamines are extensively metabolized; however, the parent compound is usually detectable in human urine. In vitro studies have shown that many cathinones and phenylethylamines are metabolized by CYP2D6 enzymes. This indicates that these drugs may have many possible drug-drug interactions and that genetic polymorphism may influence their toxicity. However, the clinical and toxicological relevance of CYP2D6 in adverse effects of cathinones and phenylethylamines is questionable, because these compounds are metabolized by other enzymes as well. The toxidromes commonly encountered after ingestion of cathinones and phenylethylamines are mainly of sympathomimetic and hallucinogenic character with a risk of excited delirium and life-threatening cardiovascular effects. CONCLUSIONS The acute and chronic toxicity of many NPSs is unknown or very sparsely investigated. There is a need for evidence-based-treatment recommendations for acute intoxications and a demand for new strategies to analyze these compounds in clinical and forensic cases.
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Affiliation(s)
- Elli Tyrkkö
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden
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Jang M, Yang W, Jeong S, Park S, Kim J. A fatal case of paramethoxyamphetamine poisoning and its detection in hair. Forensic Sci Int 2016; 266:e27-e31. [DOI: 10.1016/j.forsciint.2016.06.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/17/2016] [Accepted: 06/21/2016] [Indexed: 10/21/2022]
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Gołembiowska K, Jurczak A, Kamińska K, Noworyta-Sokołowska K, Górska A. Effect of Some Psychoactive Drugs Used as 'Legal Highs' on Brain Neurotransmitters. Neurotox Res 2016; 29:394-407. [PMID: 26501352 PMCID: PMC4786600 DOI: 10.1007/s12640-015-9569-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/28/2015] [Accepted: 10/13/2015] [Indexed: 11/29/2022]
Abstract
New psychoactive "designer drugs" are synthetic compounds developed to provide similar effects to illicit drugs of abuse, but not subjected to legal control. The rapidly changing legal status of novel psychoactive drugs triggers the development of new compounds, analogs of well-known amphetamine or mescaline. New designer drugs used as substitutes in ecstasy pills are the least investigated and can cause life-threatening effects on users. The aim of our research was to examine the effects of acute administration of 4-methoxyamphetamine (PMA, 5 and 10 mg/kg), 4-methoxy-N-methylamphetamine (PMMA, 5 and 10 mg/kg), and mephedrone (MEPH, 5, 10 and 20 mg/kg) on extracellular and tissue level of dopamine (DA), 5-hydroxytryptamine (5-HT) and their metabolites in rat brain, by microdialysis method in freely moving animals and HPLC. Similarly to 3,4-methylenedioxymethamphetamine (MDMA, 5 and 10 mg/kg) PMA, PMMA and MEPH enhanced the release of DA and 5-HT in rat striatum, nucleus accumbens, and frontal cortex. DA tissue content was increased by MEPH and PMMA in striatum, by MEPH, PMA, and PMMA in nucleus accumbens, and by PMA in frontal cortex. Instead, cortical DA level was decreased by MEPH and PMMA. MEPH did not influence 5-HT tissue level in striatum and nucleus accumbens, but decreased its level in frontal cortex. PMMA increased 5-HT content in striatum, while PMA enhanced it in nucleus accumbens and frontal cortex. Observed changes in brain monoamines and their metabolites by new psychoactive drugs suggest that these drugs may be capable of development of dependence. Further experiments are needed to fully investigate the neurotoxic and abuse potential of those drugs.
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Affiliation(s)
- Krystyna Gołembiowska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland.
| | - Alexandra Jurczak
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
| | - Katarzyna Kamińska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
| | - Karolina Noworyta-Sokołowska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
| | - Anna Górska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
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Simmler LD, Rickli A, Hoener MC, Liechti ME. Monoamine transporter and receptor interaction profiles of a new series of designer cathinones. Neuropharmacology 2013; 79:152-60. [PMID: 24275046 DOI: 10.1016/j.neuropharm.2013.11.008] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 11/11/2013] [Accepted: 11/13/2013] [Indexed: 01/28/2023]
Abstract
Psychoactive β-keto amphetamines (cathinones) are sold as "bath salts" or "legal highs" and recreationally abused. We characterized the pharmacology of a new series of cathinones, including methedrone, 4-methylethcathinone (4-MEC), 3-fluoromethcathinone (3-FMC), pentylone, ethcathinone, buphedrone, pentedrone, and N,N-dimethylcathinone. We investigated norepinephrine (NE), dopamine (DA), and serotonin (5-HT) uptake inhibition using human embryonic kidney 293 (HEK 293) cells that express the respective human monoamine transporter, the drug-induced efflux of NE, DA, and 5-HT from monoamine-preloaded cells, and binding affinity to monoamine transporters and receptors. All of the cathinones were potent NE uptake inhibitors but differed in their DA vs. 5-HT transporter inhibition profiles and monoamine release effects. Methedrone was a more potent 5-HT than DA transporter inhibitor and released NE and 5-HT similar to para-methoxymethamphetamine (PMMA), para-methoxyamphetamine (PMA), 4-methylthioamphetamine (4-MTA), and 3,4-methylenedioxymethamphetamine (MDMA). 4-MEC and pentylone equipotently inhibited all of the monoamine transporters and released 5-HT. Ethcathinone and 3-FMC inhibited NE and DA uptake and released NE, and 3-FMC also released DA similar to N-ethylamphetamine and methamphetamine. Pentedrone and N,N-dimethylcathinone were non-releasing NE and DA uptake inhibitors as previously shown for pyrovalerone cathinones. Buphedrone preferentially inhibited NE and DA uptake and also released NE. None of the cathinones bound to rodent trace amine-associated receptor 1, in contrast to the non-β-keto-amphetamines. None of the cathinones exhibited relevant binding to other monoamine receptors. In summary, we found considerable differences in the monoamine transporter interaction profiles among different cathinones and compared with related amphetamines.
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Affiliation(s)
- L D Simmler
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Hebelstrasse 2, Basel CH-4031, Switzerland
| | - A Rickli
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Hebelstrasse 2, Basel CH-4031, Switzerland
| | - M C Hoener
- Neuroscience Research, Pharmaceuticals Division, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - M E Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Hebelstrasse 2, Basel CH-4031, Switzerland.
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The analytical profile of some 4-methylthioamphetamine (4-MTA) homologues. Forensic Sci Int 2009; 192:98-114. [DOI: 10.1016/j.forsciint.2009.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 07/29/2009] [Accepted: 08/15/2009] [Indexed: 11/17/2022]
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Glennon RA, Young R, Dukat M, Chang-Fong J, El-Zahabi M. N-Methyl-1-(4-methoxyphenyl)-2-aminopropane (PMMA) and N-Methyl-1-(3,4-methylenedioxyphenyl)-2-aminopropane (MDMA) produce non-identical discriminative stimuli in rats. Pharmacol Biochem Behav 2007; 86:477-84. [PMID: 17307247 PMCID: PMC2709734 DOI: 10.1016/j.pbb.2007.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 01/03/2007] [Accepted: 01/10/2007] [Indexed: 11/19/2022]
Abstract
N-Methyl-1-(3,4-methylenedioxyphenyl)-2-aminopropane (methylenedioxymethamphetamine, MDMA, Ecstasy) and its structurally abbreviated congener N-methyl-1-(4-methoxyphenyl)-2-aminopropane (para-methoxymethamphetamine, PMMA) are chemically related designer drugs, and PMMA is sometimes sold on the clandestine market as a substitute for MDMA. Prior drug discrimination studies have found that MDMA and PMMA substitute for one another suggesting that they produce similar discriminative stimulus effects in rats. However, there also are some indications that the two agents produce distinct stimulus effects. In this study, further comparisons were made between the stimulus effects of these two agents. Sprague-Dawley rats were trained to discriminate either 1.25 mg/kg of PMMA or 1.5 mg/kg of MDMA from saline vehicle in a two-lever operant paradigm. A structure-activity comparison revealed that MDMA and PMMA behave similarly upon homologation of their terminal amine substituents. In contrast, the PMMA stimulus, unlike an MDMA stimulus, failed to generalize completely to the psychostimulant cocaine, 8-hydroxy-2-(N,N-di-n-propylamino)tetralin (8-OH DPAT), and R(-)-1-(3-methoxyphenyl)-2-aminopropane [R(-)MMA]. In an additional group of animals, a (+)amphetamine stimulus partially generalized to R(-)MMA. Taken together, the results argue and re-emphasize the conclusion that the stimulus effects produced by MDMA and PMMA are similar, but non-identical, and that PMMA is the less "stimulant-like" of the two.
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Affiliation(s)
- Richard A Glennon
- Department of Medicinal, Chemistry School of Pharmacy Medical College of Virginia, Virginia Commonwealth University Richmond, VA 23298-0540, USA.
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Carmo H, Brulport M, Hermes M, Oesch F, de Boer D, Remião F, Carvalho F, Schön MR, Krebsfaenger N, Doehmer J, Bastos MDL, Hengstler JG. CYP2D6 increases toxicity of the designer drug 4-methylthioamphetamine (4-MTA). Toxicology 2007; 229:236-44. [PMID: 17156908 DOI: 10.1016/j.tox.2006.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 10/25/2006] [Accepted: 10/27/2006] [Indexed: 10/23/2022]
Abstract
4-Methylthioamphetamine (4-MTA) belongs to a group of new amphetamine derivatives that is usually sold as "ecstasy" or "flatliners" on the illicit drug market. Large interindividual differences in 4-MTA mediated toxicity have been reported in humans. Therefore, we tested whether CYP2D6 or its variant alleles as well as CYP3A4 influence the susceptibility to 4-MTA. For this purpose, we used the colony formation assay with Chinese hamster lung fibroblast V79 cells expressing human wild-type CYP2D6 (CYP2D6*1), the low activity alleles CYP2D6*2, CYP2D6*9, as well as human CYP3A4. The obtained results showed that the expression of wild type CYP2D6*1 clearly enhanced the susceptibility to the cytotoxic effects of 4-MTA compared with the parental cells devoid of CYP-dependent enzymatic activity. Toxicity in V79 CYP2D6*1 was also higher compared to the V79 cell lines expressing the low activity alleles CYP2D6*2 and CYP2D6*9. In contrast to CYP2D6, the CYP3A4 isoenzyme did not enhance 4-MTA toxicity. In conclusion, our results suggest that CYP2D6 rapid metabolizers may be more susceptible to 4-MTA toxicity than CYP2D6 poor metabolizers.
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Affiliation(s)
- Helena Carmo
- REQUIMTE, Toxicology Department, Faculty of Pharmacy, University of Porto, Rua Aníbal Cunha 164, 4099-030 Porto, Portugal.
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Young R, Khorana N, Bondareva T, Glennon RA. Pizotyline effectively attenuates the stimulus effects of N-methyl-3,4-methylenedioxyamphetamine (MDMA). Pharmacol Biochem Behav 2005; 82:404-10. [PMID: 16253319 DOI: 10.1016/j.pbb.2005.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 08/18/2005] [Accepted: 09/02/2005] [Indexed: 10/25/2022]
Abstract
MDMA (N-methyl-3,4-methylenedioxyamphetamine) produces a discriminative stimulus (DS) effect in animals, but attempts to completely block this action with selective neurotransmitter antagonists have not been very successful. Biochemically, MDMA can increase synaptic levels of serotonin, dopamine, and norepinephrine that, conceivably, might interact with multiple populations or subpopulations of neurotransmitter receptors. The present study attempted to antagonize the DS effects of MDMA using the nonselective agents clozapine, cyproheptadine, and pizotyline. An extensive and comparative radioligand binding profile was also obtained for the latter two agents. The purported antagonists were administered in combination with the training dose of MDMA to groups of Sprague-Dawley rats trained to discriminate 1.5 mg/kg of MDMA from saline vehicle in a standard two-lever operant paradigm using a VI-15s schedule of reinforcement. Clozapine was without effect at the doses evaluated, and cyproheptadine only partially attenuated MDMA-appropriate responding. In contrast, pizotyline (AD50=2.5 mg/kg), in combination with the MDMA training dose, resulted in a dose related decrease in percent drug-appropriate responding to saline levels. In a separate group of animals trained to discriminate the structurally-related agent N-methyl-1-(4-methoxyphenyl)-2-aminopropane (PMMA) from vehicle, pretreatment with pizotyline also resulted in a substantial decrease in drug-appropriate responding. The results with cyproheptadine and pizotyline in the binding assays confirmed that these agents display high affinity for multiple subpopulations of serotonergic, dopaminergic, adrenergic, histaminergic, and cholinergic receptors. The overall results of the present investigation indicate that pizotyline, which is clinically available in some countries, might be of clinical utility in the treatment of MDMA overdose.
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MESH Headings
- Animals
- Central Nervous System Stimulants/antagonists & inhibitors
- Central Nervous System Stimulants/pharmacology
- Cyproheptadine/pharmacology
- Discrimination, Psychological/drug effects
- Dose-Response Relationship, Drug
- Generalization, Psychological
- Hallucinogens/antagonists & inhibitors
- Hallucinogens/pharmacokinetics
- Hallucinogens/pharmacology
- Male
- Methamphetamine/analogs & derivatives
- Methamphetamine/pharmacokinetics
- Methamphetamine/pharmacology
- N-Methyl-3,4-methylenedioxyamphetamine/antagonists & inhibitors
- N-Methyl-3,4-methylenedioxyamphetamine/pharmacokinetics
- N-Methyl-3,4-methylenedioxyamphetamine/pharmacology
- Pizotyline/pharmacokinetics
- Pizotyline/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Neurotransmitter/drug effects
- Receptors, Neurotransmitter/metabolism
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/metabolism
- Serotonin Antagonists/pharmacokinetics
- Serotonin Antagonists/pharmacology
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Affiliation(s)
- Richard Young
- Department of Medicinal Chemistry, School of Pharmacy, Medical College of Virginia Campus, Virginia Commonwealth University, Box 980540 Richmond, Virginia 23298-0540, United States
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Khorana N, Pullagurla MR, Dukat M, Young R, Glennon RA. Stimulus effects of three sulfur-containing psychoactive agents. Pharmacol Biochem Behav 2004; 78:821-6. [PMID: 15301941 DOI: 10.1016/j.pbb.2004.05.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 02/17/2004] [Accepted: 05/28/2004] [Indexed: 11/29/2022]
Abstract
Two agents gaining popularity on the illicit drug market are the phenylalkylamines 4-MTA and 2C-T-7 [or 1-(4-methylthiophenyl)-2-aminopropane and 2-(2,5-dimethoxy-4-n-propylthiophenyl)-1-aminoethane, respectively]. At this time, there exists a paucity of information on the behavioral actions of these sulfur-containing agents. The present investigation examined these agents, and the N-monomethyl analog of 4-MTA (i.e., 4-MTMA), in tests of stimulus generalization (substitution) using a two-lever drug discrimination task with groups of rats trained to discriminate either the hallucinogen DOM [1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane], the stimulant cocaine, or the empathogen MDMA from vehicle. 4-MTA and its N-monomethyl analog 4-MTMA (ED50 = 0.8 mg/kg in both cases) substituted only for the MDMA stimulus, whereas 2C-T-7 (ED50 = 0.8 mg/kg) substituted only for the DOM stimulus. Thus, at the doses examined, 4-MTA and 4-MTMA appear to be MDMA-like agents, and 2C-T-7 seems best classified as a DOM-like hallucinogen. These results provide additional data that extend the structure-activity relationships of phenylalkylamines and that are consistent with what little is currently known about the action of 4-MTA and 2C-T-7 in humans.
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Affiliation(s)
- Nantaka Khorana
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298-0540, USA
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Khorana N, Pullagurla MR, Young R, Glennon RA. Comparison of the discriminative stimulus effects of 3,4-methylenedioxymethamphetamine (MDMA) and cocaine: asymmetric generalization. Drug Alcohol Depend 2004; 74:281-7. [PMID: 15194206 DOI: 10.1016/j.drugalcdep.2004.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Revised: 12/09/2003] [Accepted: 01/13/2004] [Indexed: 10/26/2022]
Abstract
Evidence suggests that +/- 3,4-methylenedioxymethamphetamine (MDMA) and psychostimulants produce similar but non-identical stimulus effects in animals. To examine this hypothesis, groups of rats were trained to discriminate either MDMA (1.5 mg/kg) or cocaine (8 mg/kg) from saline vehicle using a two-lever operant procedure under a variable interval (VI) 15 s schedule of reinforcement. Once the animals were trained, tests of stimulus generalization were conducted with +/- MDMA, cocaine, S+ MDMA, and R- MDMA. As previously demonstrated, both S+ MDMA and R- MDMA (ED50 = 0.8 and 1.2 mg/kg, respectively) substituted for +/- MDMA. Stimulus generalization also occurred upon administration of cocaine (ED50 = 4.6 mg/kg) to the +/- MDMA-trained animals. In the cocaine-trained animals, however, stimulus generalization did not occur to +/- MDMA, S+ MDMA nor R- MDMA. Receptor binding profiles for MDMA and cocaine were compared in an effort to identify any novel and common receptor-based mechanism(s) to explain stimulus generalization of MDMA-trained animals to the effects of cocaine, but only their actions on neurotransmitter transporters seem applicable. Taken together, the results indicate that stimulus substitution between MDMA and cocaine is asymmetric and suggest that although similarities exist between the stimulus actions of MDMA and cocaine, differences might be explained by their differential effects on increasing synaptic concentrations of serotonin (5-HT), dopamine (DA), and/or norepinephrine (NE).
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Affiliation(s)
- Nantaka Khorana
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298-0540, USA
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