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Burke EL, Desai RI. Reinforcing and adverse observable effects of nicotine and minor tobacco alkaloids in squirrel monkeys. Drug Alcohol Depend 2024; 258:111280. [PMID: 38614019 PMCID: PMC11117166 DOI: 10.1016/j.drugalcdep.2024.111280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/15/2024]
Abstract
The most prevalent psychoactive chemical in tobacco smoke is nicotine, which has been shown to maintain tobacco consumption as well as cause acute adverse effects at high doses, like nausea and emesis. Recent studies in laboratory animals have suggested that many non-nicotine constituents of tobacco smoke (e.g., minor tobacco alkaloids) may also contribute to tobacco's overall reinforcing and adverse effects. Here, we used intravenous (IV) self-administration (n = 3) and observation (n = 4) procedures in squirrel monkeys to, respectively, compare the reinforcing and adverse observable effects of nicotine and three prominent minor tobacco alkaloids, nornicotine, anatabine, and myosmine. In self-administration studies, male squirrel monkeys were trained to respond under a second-order fixed-interval schedule of reinforcement and dose-effects functions for nicotine and each of the minor tobacco alkaloids nornicotine, anatabine, and mysomine were determined. Observation studies were conducted in a different group of male squirrel monkeys to quantify the ability of nicotine, nornicotine, anatabine, and mysomine to produce adverse overt effects, including hypersalivation, emesis, and tremors. Results show that nicotine and to a lesser extent nornicotine were readily self-administered, whereas anatabine and myosmine were not. In observation studies, all minor tobacco alkaloids produced adverse observable effects that were either comparable or more pronounced than nicotine. Collectively, the present results showing that nicotine and the minor tobacco alkaloids nornicotine, anatabine, and myosmine produce differential reinforcing and acute adverse observable effects in monkeys provides further evidence that these constituents may differently contribute to the psychopharmacological and adverse effects of tobacco consumption.
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Affiliation(s)
- Emily L Burke
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA; Integrative Neurochemistry Laboratory, Behavioral Biology Program, McLean Hospital, Belmont, MA 02478, USA
| | - Rajeev I Desai
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA; Integrative Neurochemistry Laboratory, Behavioral Biology Program, McLean Hospital, Belmont, MA 02478, USA.
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Abraham AD, Wiley JL, Marusich JA. Experimenter administered Δ 9-THC decreases nicotine self-administration in a rat model. Pharmacol Biochem Behav 2023; 231:173632. [PMID: 37690617 PMCID: PMC10543614 DOI: 10.1016/j.pbb.2023.173632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/22/2023] [Accepted: 09/06/2023] [Indexed: 09/12/2023]
Abstract
BACKGROUND The co-use of nicotine and cannabis has been steadily rising in the United States. Rodent studies suggest that delta-9-tetrahydrocannabinol (THC) could increase addictive qualities of nicotine, but whether repeated THC exposure alters self-administration of nicotine has not been tested. We hypothesized that THC would increase the reinforcing effects of nicotine and alter nicotine intake. METHODS Adult male and female Sprague-Dawley rats were treated with THC (0, 3, 30 mg/kg) daily for 14 days prior to and during training for intravenous self-administration of nicotine. Rats were allowed to self-administer nicotine for several weeks, then tested for sensitivity to nicotine dose through multiple determinations of a nicotine dose-effect curve with or without THC pretreatment. A separate set of rats were trained on fixed ratio responding for sucrose and assessed for THC effects on behavior. RESULTS Post-session THC decreased nicotine self-administration in male and female rats throughout acquisition and maintenance and increased the latency to stable rates of nicotine intake during acquisition. Post-session THC shifted nicotine dose-effect curves downward, and pre-session THC suppressed responding at higher nicotine doses. Unlike nicotine, responding for sucrose was not affected by post-session THC. Pre-session THC decreased responding for sucrose, particularly for THC-naïve rats. CONCLUSIONS Repeated post-session THC decreased nicotine-taking behaviors but did not alter sucrose responding. Thus, post-session THC may alter sensitivity to nicotine. Pre-session THC treatment decreased lever pressing in both sucrose and nicotine studies, indicating this effect was nonspecific. These studies show that THC modulates patterns of nicotine intake in rat models.
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Affiliation(s)
- Antony D Abraham
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC 27709, USA
| | - Jenny L Wiley
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC 27709, USA
| | - Julie A Marusich
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC 27709, USA.
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Dang B, Jia W, Ma S, Zhang X, Huang Y, Huang W, Han D, Zhang K, Zhao F, Zhang Y, Xu Z. Characterization of a novel nornicotine-degrading strain Mycolicibacterium sp. SMGY-1XX from a nornicotine-degrading consortium and preliminary elucidation of its biodegradation pathway by multi-omics analysis. JOURNAL OF HAZARDOUS MATERIALS 2023; 457:131777. [PMID: 37290356 DOI: 10.1016/j.jhazmat.2023.131777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/14/2023] [Accepted: 06/02/2023] [Indexed: 06/10/2023]
Abstract
Nicotine and nornicotine are all toxic alkaloids involved in the formation of carcinogenic tobacco-specific nitrosamines. Microbes play an important role in removing these toxic alkaloids and their derivatives from tobacco-polluted environments. By now, microbial degradation of nicotine has been well studied. However, limited information is available on the microbial catabolism of nornicotine. In the present study, a nornicotine-degrading consortium was enriched from a river sediment sample and characterized by metagenomic sequencing using a combination of Illumina and Nanopore technologies. The metagenomic sequencing analysis demonstrated that Achromobacter, Azospirillum, Mycolicibacterium, Terrimonas, and Mycobacterium were the dominant genera in the nornicotine-degrading consortium. A total of 7 morphologically distinct bacterial strains were isolated from the nornicotine-degrading consortium. These 7 bacterial strains were characterized by whole genome sequencing and examined for their ability to degrade nornicotine. Based on a combination of 16 S rRNA gene similarity comparisons, 16 S rRNA gene-based phylogenetic analysis, and ANI analysis, the accurate taxonomies of these 7 isolated strains were identified. These 7 strains were identified as Mycolicibacterium sp. strain SMGY-1XX, Shinella yambaruensis strain SMGY-2XX, Sphingobacterium soli strain SMGY-3XX, Runella sp. strain SMGY-4XX, Chitinophagaceae sp. strain SMGY-5XX, Terrimonas sp. strain SMGY-6XX, Achromobacter sp. strain SMGY-8XX. Among these 7 strains, Mycolicibacterium sp. strain SMGY-1XX, which has not been reported previously to have the ability to degrade nornicotine or nicotine, was found to be capable of degrading nornicotine, nicotine as well as myosmine. The degradation intermediates of nornicotine and myosmine by Mycolicibacterium sp. strain SMGY-1XX were determined and the nornicotine degradation pathway in strain SMGY-1XX was proposed. Three novel intermediates, myosmine, pseudooxy-nornicotine, and γ-aminobutyrate, were identified during the nornicotine degradation process. Further, the most likely candidate genes responsible for nornicotine degradation in Mycolicibacterium sp. strain SMGY-1XX were identified by integrating genomic analysis, transcriptomic analysis, and proteomic analysis. The findings in this study will help to expand our understanding on the microbial catabolism of nornicotine and nicotine and provide new insights into the nornicotine degradation mechanism by consortia and pure culture, laying a foundation for the application of strain SMGY-1XX for the removal, biotransformation, or detoxification of nornicotine.
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Affiliation(s)
- Bingjun Dang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.
| | - Wei Jia
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Shuanglong Ma
- College of Resources and Environmental Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Xiaoping Zhang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China; Flavors and Fragrance Engineering & Technology Research Center of Henan Province, Zhengzhou 450002, China
| | - Yao Huang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Wuxing Huang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Dan Han
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Kai Zhang
- School of Geographic Sciences, Xinyang Normal University, Xinyang 464000, China
| | - Fanchong Zhao
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Yuwei Zhang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Zicheng Xu
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.
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Marusich JA, Palmatier MI. Development of a nicotine aerosol self-administration model in rats and the effects of e-liquid flavors. Behav Pharmacol 2023; 34:141-153. [PMID: 36752651 PMCID: PMC10006336 DOI: 10.1097/fbp.0000000000000717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Electronic nicotine delivery system (ENDS) use is maintained by the positive reinforcement associated with preferred flavors. These flavors become conditioned reinforcers through pairings with primary reinforcers. This study sought to extend prior research with intravenous nicotine self-administration and develop a more ecologically valid preclinical model of aerosol self-administration in rats that incorporated flavors paired with sucrose. Rats were first trained to respond for oral sucrose with or without raspberry flavor to establish the flavor as a conditioned reinforcer for some groups. Rats were then exposed to aerosol self-administration. All groups responded for raspberry-flavored aerosol with or without nicotine. Rats responded more for raspberry flavored sucrose than unflavored sucrose. Despite raspberry increasing responding for sucrose, the flavor did not function as a conditioned reinforcer during aerosol self-administration and did not increase responding for nicotine. Throughout the aerosol self-administration phase, most groups responded more on the active than inactive lever, and some groups increased their response when the fixed ratio value was increased. At the end of the study, rats in nicotine groups earned similar or fewer aerosol deliveries than rats in vehicle groups. Aerosolized nicotine did not function as a reinforcer in this study, whereas aerosolized raspberry flavor may have maintained self-administration. Further preclinical investigation is needed to articulate the impact of flavors on ENDS use and whether they offset some aversive effects of nicotine or maintain responding on their own. If flavors reduce some aversive effects of self-administered nicotine, then policies to regulate flavors in e-liquids are prudent.
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Affiliation(s)
- Julie A Marusich
- Center for Drug Discovery, RTI International, Research Triangle Park, NC
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Frie JA, Nolan CJ, Murray JE, Khokhar JY. Addiction-Related Outcomes of Nicotine and Alcohol Co-use: New Insights Following the Rise in Vaping. Nicotine Tob Res 2022; 24:1141-1149. [PMID: 34758090 PMCID: PMC9278825 DOI: 10.1093/ntr/ntab231] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/03/2021] [Accepted: 11/02/2021] [Indexed: 11/13/2022]
Abstract
PURPOSE Nicotine and alcohol-containing products are some of the most commonly used substances of abuse and are both leading causes of preventable death. These substances also have significant interactions that have additive and, in some cases, multiplicative effects on the health consequences of their use. Thus, to reduce these negative consequences, it is important to understand the abuse liability of nicotine and alcohol in combination, especially in the most relevant use cases among those who are most vulnerable. Specifically, as tobacco cigarette use is continually decreasing, vaping is quickly replacing cigarettes as the primary mode of nicotine use. This pattern is especially true in adolescent populations in which vaping has grown considerably. Particularly concerning is that adolescents are more vulnerable than adults to the negative consequences of substance use. It is therefore imperative to revisit the literature as it relates to the rising state of co-use of vaping products with alcohol. Here, we review the clinical outcomes of nicotine and alcohol co-use as they relate to the abuse liability of each individually. Special attention is paid to adolescent findings, where available, as well as investigations that use nontobacco nicotine products as these may more accurately reflect the more recent trends of co-use. IMPLICATIONS Though nicotine alone has previously been considered a proxy for tobacco and tobacco cigarette use, combustible routes of administration have been decreasing. They are, instead, being replaced by e-cigarettes that do not involve other tobacco constituents and contain additional nonnicotine constituents of their own. Unfortunately, the literature remains limited with regard to e-cigarettes and their interactions with other substances, especially their prevalent co-use with alcohol. This review attempts to discuss the current literature on nicotine and alcohol co-use in the context of the vaping epidemic, predominantly focusing on addiction-related outcomes and why e-cigarette use may be unique.
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Affiliation(s)
- Jude A Frie
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
- Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Caitlin J Nolan
- Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
- Department of Psychology, University of Guelph, Guelph, ON, Canada
| | - Jennifer E Murray
- Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
- Department of Psychology, University of Guelph, Guelph, ON, Canada
| | - Jibran Y Khokhar
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
- Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
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Anatabine, Nornicotine, and Anabasine Reduce Weight Gain and Body Fat through Decreases in Food Intake and Increases in Physical Activity. J Clin Med 2022; 11:jcm11030481. [PMID: 35159932 PMCID: PMC8837150 DOI: 10.3390/jcm11030481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 12/23/2022] Open
Abstract
Obesity is a leading cause of preventable death in the United States. Currently approved pharmacotherapies for the treatment of obesity are associated with rebound weight gain, negative side effects, and the potential for abuse. There is a need for new treatments with fewer side effects. Minor tobacco alkaloids (MTAs) are potential candidates for novel obesity pharmacotherapies. These alkaloids are structurally related to nicotine, which can help reduce body weight, but without the same addictive potential. The purpose of the current study was to examine the effects of three MTAs (nornicotine, anatabine, and anabasine) and nicotine on weight gain, body composition, chow intake, and physical activity. We hypothesized that the MTAs and nicotine would reduce weight gain through reductions in chow intake and increases in physical activity. To test this, male Sprague Dawley rats were housed in metabolic phenotyping chambers. Following acclimation to these chambers and to (subcutaneous (sc)) injections of saline, animals received daily injections (sc) of nornicotine, anabasine, anatabine, or nicotine for one week. Compared to saline-injected animals that gained body weight and body fat during the treatment phase, injections of nornicotine and anatabine prevented additional weight gain, alongside reductions in body fat. Rats receiving anabasine and nicotine gained body weight at a slower rate relative to rats receiving saline injections, and body fat remained unchanged. All compounds reduced the intake of chow pellets. Nornicotine and nicotine produced consistent increases in physical activity 6 h post-injection, whereas anabasine’s and anatabine’s effects on physical activity were more transient. These results show that short-term, daily administration of nornicotine, anabasine, and anatabine has positive effects on weight loss, through reductions in body fat and food intake and increases in physical activity. Together, these findings suggest that MTAs are worthy of further investigations as anti-obesity pharmacotherapies.
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Leone FT, Evers-Casey S. Tobacco Use Disorder. Med Clin North Am 2022; 106:99-112. [PMID: 34823737 PMCID: PMC8630801 DOI: 10.1016/j.mcna.2021.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Tobacco use disorder is highly prevalent; more than a billion individuals use tobacco worldwide. Popular views on the addictive potential of tobacco often underestimate the complex neural adaptations that underpin continued use. Although sometimes trivialized as a minor substance, effects of nicotine on behavior lead to profound morbidity over a lifetime of exposure. Innovations in processing have led to potent forms of tobacco and delivery devices. Proactive treatment strategies focus on pharmacotherapeutic interventions. Innovations on the horizon hold promise to help clinicians address this problem in a phenotypically tailored manner. Efforts are needed to prevent tobacco use for future generations.
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Affiliation(s)
- Frank T Leone
- Comprehensive Smoking Treatment Program, Penn Lung Center, Suite 251 Wright-Saunders Building, 51 North 39th Street, Philadelphia, PA, USA; Abramson Cancer Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA.
| | - Sarah Evers-Casey
- Comprehensive Smoking Treatment Program, Penn Lung Center, Suite 251 Wright-Saunders Building, 51 North 39th Street, Philadelphia, PA, USA
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Kassner M, Eaton JB, Tang N, Petit JL, Meurice N, Yin HH, Whiteaker P. High-throughput cell-based assays for identifying antagonists of multiple smoking-associated human nicotinic acetylcholine receptor subtypes. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2022; 27:68-76. [PMID: 35058178 PMCID: PMC8816891 DOI: 10.1016/j.slasd.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
There is substantial evidence that in addition to nicotine, other compounds found in tobacco smoke significantly influence smoking behavior. Further, recent years have seen an explosion in the availability of non-combusted products that deliver nicotine, such as e-cigarettes and “home-brew” vaping devices that are essentially unregulated. There are many thousands of compounds in tobacco smoke alone, and new products are constantly introducing new compounds. Uncovering which of these compounds are active, across multiple smoking-relevant subtypes of the nicotinic acetylcholine receptor (nAChR) that influence tobacco/nicotine addiction, requires a high-throughput screening (HTS) approach. Accordingly, we developed a panel of HTS-friendly cell-based assays, all performed in the same cellular background and using the same membrane potential dye readout, to measure the function of the α3β4-, α4β2-, and α6β2-nAChR subtypes. These subtypes have each been prominently and consistently associated with human smoking behavior. We validated our assays by performing pilot screening of an expanded set of the Prestwick FDA-approved drug library. The screens displayed excellent performance parameters, and moderate hit rates (mean of 1.2% across all three assays) were achieved when identifying antagonists (chosen since effects of endogenous antagonists on consumption of nicotine/tobacco products are under-studied). Validation rates using an orthogonal assay (86Rb+ efflux) averaged 73% across the three assays. The resulting panel of assays represents a valuable new platform with which to screen and identify nAChR subtype-selective compounds. This provides a resource for identifying smoking-related compounds in both combusted and non-combusted tobacco products, with potential relevance in the search for additional smoking-cessation therapies.
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Affiliation(s)
- Michelle Kassner
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States
| | - J Brek Eaton
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, United States
| | - Nanyun Tang
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States
| | - Joachim L Petit
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ 85259, United States
| | - Nathalie Meurice
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ 85259, United States
| | - Hongwei Holly Yin
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States.
| | - Paul Whiteaker
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, United States.
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LeSage MG. Stimulus functions of nicotine. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 93:133-170. [PMID: 35341565 PMCID: PMC9438898 DOI: 10.1016/bs.apha.2021.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Behavioral pharmacology has made vital contributions to the concepts and methods used in tobacco and other drug use research, and is largely responsible for the now generally accepted notion that nicotine is the primary component in tobacco that engenders and maintains tobacco use. One of the most important contributions of behavioral pharmacology to the science of drug use is the notion that drugs can act as environmental stimuli that control behavior in many of the same ways as other stimuli (e.g., visual, gustatory, olfactory). The purpose of this chapter is to provide an overview of research that illustrates the respondent and operant stimulus functions of nicotine, using a contemporary taxonomy of stimulus functions as a general framework. Each function is formally defined and examples from research on the behavioral pharmacology of nicotine are presented. Some of the factors that modulate each function are also discussed. The role of nicotine's stimulus functions in operant and respondent theories of tobacco use is examined and some suggestions for future research are presented. The chapter illustrates how a taxonomy of stimulus functions can guide conceptions of tobacco use and direct research and theory accordingly.
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Levin ED, Wells C, Pace C, Abass G, Hawkey A, Holloway Z, Rezvani AH, Rose JE. Self-administration by female rats of low doses of nicotine alone vs. nicotine in tobacco smoke extract. Drug Alcohol Depend 2021; 228:109073. [PMID: 34600263 DOI: 10.1016/j.drugalcdep.2021.109073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND Nicotine has reinforcing effects, but there are thousands of other compounds in tobacco, some of which might interact with nicotine reinforcement. AIMS This rat study was conducted to determine if nicotine self-administration is altered by co-administration of the complex mixture of compounds in tobacco smoke extract (TSE). METHODS Female Sprague-Dawley rats were tested for self-administration of low doses of nicotine (3 or 10 µg/kg/infusion) at three different rates of reinforcement (FR1, FR3 and FR5) over three weeks either alone or together with the complex mixture of tobacco smoke extract (TSE). RESULTS Rats self-administering 3 µg/kg/infusion of nicotine alone showed a rapid initiation on an FR1 schedule, but declined with FR5. Rats self-administering nicotine in TSE acquired self-administration more slowly, but increased responding over the course of the study. With 10 µg/kg/infusion rats self-administered significantly more nicotine alone than rats self-administering the same nicotine dose in TSE. Rats self-administering nicotine alone took significantly more infusions with the 10 than the 3 µg/kg/infusion dose, whereas rats self-administering nicotine in TSE did not. Nicotine in TSE led to a significantly greater locomotor hyperactivity at a dose of 0.1 mg/kg compared to rats that received nicotine alone. Rats self-administering nicotine alone had significantly more responding on the active vs. inactive lever, but rats self-administering the same nicotine doses in TSE did not. CONCLUSIONS Self-administration of nicotine in a purer form appears to be more clearly discriminated and dose-related than nicotine self-administered in the complex mixture of TSE.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA.
| | - Corinne Wells
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Caroline Pace
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Grant Abass
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Andrew Hawkey
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Zade Holloway
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | - Jed E Rose
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
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Doyle MR, Sulima A, Rice KC, Collins GT. Influence of Contingent and Noncontingent Drug Histories on the Development of High Levels of MDPV Self-Administration. J Pharmacol Exp Ther 2021; 379:108-116. [PMID: 34413199 DOI: 10.1124/jpet.121.000655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 08/16/2021] [Indexed: 11/22/2022] Open
Abstract
A subset of rats that self-administer 3,4-methylenedioxypyrovalerone (MDPV) develop unusually high levels of drug taking. A history of responding maintained by cocaine, but not food, prevents the development of this high-responder phenotype; however, it is unclear how histories of noncontingent cocaine exposure or self-administering drugs from other pharmacological classes would affect its development. In the current studies, 5 groups of male Sprague-Dawley rats were used to determine whether histories of responding maintained by drugs from different pharmacological classes (e.g., MDPV, cocaine, fentanyl, nicotine, or ketamine) would differentially impact the development of the high-responder phenotype when MDPV was available for self-administration. Two additional groups were used to determine whether noncontingent exposure to cocaine would prevent the development of the high-responder phenotype when MDPV was available for self-administration, and whether noncontingent exposure to MDPV would facilitate the development of the high-responder phenotype when cocaine was available for self-administration. Consistent with previous reports, a history of response-contingent cocaine, and to a lesser extent noncontingent cocaine, prevented the MDPV high-responder phenotype; however, when responding was initially maintained by fentanyl, nicotine, or ketamine, the MDPV high-responder phenotype developed in ∼45% of rats. By manipulating behavioral and pharmacological histories prior to evaluating MDPV self-administration, the current studies provide additional evidence that a history of response-contingent (or noncontingent) cocaine can prevent the transition from well regulated to aberrant drug-taking when responding is maintained by MDPV. Although the mechanism(s) that underlies this novel high-responder phenotype are unknown, elucidation may provide insight into individual differences relating to substance use disorder. SIGNIFICANCE STATEMENT: A subset of outbred Sprague-Dawley rats self-administer high levels of the synthetic cathinone 3,4-methylenedioxypyrovalerone (MDPV). Understanding the behavioral and/or pharmacological factors that can prevent the development of dysregulated MDPV self-administration may provide insight into individual differences in vulnerability to develop a substance use disorder.
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Affiliation(s)
- Michelle R Doyle
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
| | - Agnieszka Sulima
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
| | - Kenner C Rice
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
| | - Gregory T Collins
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
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Ryu IS, Kim J, Yang JH, Seo SY, Sohn S, Kim S, Lee K, Seo JW, Choe ES. Exposure to Commercial Cigarette Smoke Produces Psychomotor Sensitization Via Hyperstimulation of Glutamate Response in the Dorsal Striatum. Brain Sci 2020; 11:brainsci11010014. [PMID: 33374316 PMCID: PMC7830476 DOI: 10.3390/brainsci11010014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/11/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
Cigarette smoke is a highly complex mixture of nicotine and non-nicotine constituents. Exposure to cigarette smoke enhances tobacco dependence by potentiating glutamatergic neurotransmission via stimulation of nicotinic acetylcholine receptors (nAChRs). We investigated the effects of nicotine and non-nicotine alkaloids in the cigarette smoke condensates extracted from two commercial cigarette brands in South Korea (KCSC A and KCSC B) on psychomotor behaviors and glutamate levels in the dorsal striatum. Repeated and challenge administration of KCSCs (nicotine content: 0.4 mg/kg, subcutaneous) increased psychomotor behaviors (ambulatory, rearing, and rotational activities) and time spent in psychoactive behavioral states compared to exposure to nicotine (0.4 mg/kg) alone. The increase in psychomotor behaviors lasted longer when exposed to repeated and challenge administration of KCSCs compared to nicotine alone. In parallel with sustained increase in psychomotor behaviors, repeated administration of KCSCs also caused long-lasting glutamate release in the dorsal striatum compared to nicotine alone. KCSC-induced changes in psychomotor behaviors and glutamate levels in the dorsal striatum were found to be strongly correlated. These findings suggest that non-nicotine alkaloids in commercial cigarette smoke synergistically act with nicotine on nAChRs, thereby upregulating glutamatergic response in the dorsal striatum, which contributes to the hypersensitization of psychomotor behaviors.
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Affiliation(s)
- In Soo Ryu
- Department of Biological Sciences, Pusan National University, 63-2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea; (J.K.); (J.H.Y.); (S.Y.S.); (S.S.); (S.K.)
- Research Center for Convergence Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon 34114, Korea;
- Correspondence: (I.S.R.); (E.S.C.); Tel.: +82-42-610-8293 (I.S.R.); +82-51-510-2272 (E.S.C.)
| | - Jieun Kim
- Department of Biological Sciences, Pusan National University, 63-2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea; (J.K.); (J.H.Y.); (S.Y.S.); (S.S.); (S.K.)
| | - Ju Hwan Yang
- Department of Biological Sciences, Pusan National University, 63-2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea; (J.K.); (J.H.Y.); (S.Y.S.); (S.S.); (S.K.)
| | - Su Yeon Seo
- Department of Biological Sciences, Pusan National University, 63-2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea; (J.K.); (J.H.Y.); (S.Y.S.); (S.S.); (S.K.)
- Korean Medicine Fundamental Research Division, Korea Institute of Oriental Medicine, 1672 Yuseong-daero, Yuseong-gu, Daejeon 34054, Korea
| | - Sumin Sohn
- Department of Biological Sciences, Pusan National University, 63-2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea; (J.K.); (J.H.Y.); (S.Y.S.); (S.S.); (S.K.)
| | - Sunghyun Kim
- Department of Biological Sciences, Pusan National University, 63-2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea; (J.K.); (J.H.Y.); (S.Y.S.); (S.S.); (S.K.)
| | - Kyuhong Lee
- Inhalation Toxicology Research Center, Korea Institute of Toxicology, 30 Baekhak 1-gil, Jeongeup 56212, Korea;
| | - Joung-Wook Seo
- Research Center for Convergence Toxicology, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon 34114, Korea;
| | - Eun Sang Choe
- Department of Biological Sciences, Pusan National University, 63-2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea; (J.K.); (J.H.Y.); (S.Y.S.); (S.S.); (S.K.)
- Correspondence: (I.S.R.); (E.S.C.); Tel.: +82-42-610-8293 (I.S.R.); +82-51-510-2272 (E.S.C.)
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13
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Ding ZM, Gao Y, Sentir AM, Tan X. Self-Administration of Cotinine in Wistar Rats: Comparisons to Nicotine. J Pharmacol Exp Ther 2020; 376:338-347. [PMID: 33361363 DOI: 10.1124/jpet.120.000367] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
Nicotine is the major addictive component in tobacco. Cotinine is the major metabolite of nicotine and a weak agonist for nicotinic acetylcholine receptors (nAChRs). Nicotine supports self-administration in rodents. However, it remains undetermined whether cotinine can be self-administered. This study aimed to characterize cotinine self-administration in rats, to compare effects of cotinine to those of nicotine, and to determine potential involvement of nAChRs in cotinine's effects. Adult Wistar rats were trained to self-administer cotinine or nicotine (0.0075, 0.015, 0.03, or 0.06 mg/kg per infusion) under fixed-ratio (FR) and progressive-ratio (PR) schedules. Blood nicotine and cotinine levels were determined after the last FR session. Effects of mecamylamine, a nonselective nAChR antagonist, and varenicline, a partial agonist for α4β2* nAChRs, on cotinine and nicotine self-administration were determined. Rats readily acquired cotinine self-administration, responded more on active lever, and increased motivation to self-administer cotinine when the reinforcement requirement increased. Blood cotinine levels ranged from 77 to 792 ng/ml. Nicotine induced more infusions at lower doses during FR schedules and greater breakpoints at higher doses during the PR schedule than cotinine. There was no difference in cotinine self-administration between male and female rats. Mecamylamine and varenicline attenuated nicotine but not cotinine self-administration. These results indicate that cotinine was self-administered by rats. These effects of cotinine were less robust than nicotine and exhibited no sex difference. nAChRs appeared to be differentially involved in self-administration of nicotine and cotinine. These results suggest cotinine may play a role in the development of nicotine use and misuse. SIGNIFICANCE STATEMENT: Nicotine addiction is a serious public health problem. Cotinine is the major metabolite of nicotine, but its involvement in nicotine reinforcement remains elusive. Our findings indicate that cotinine, at doses producing clinically relevant blood cotinine levels, supported intravenous self-administration in rats. Cotinine self-administration was less robust than nicotine. Mecamylamine and varenicline attenuated nicotine but not cotinine self-administration. These results suggest cotinine may play a role in the development of nicotine use and misuse.
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Affiliation(s)
- Zheng-Ming Ding
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
| | - Yong Gao
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
| | - Alena M Sentir
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
| | - Xiaoying Tan
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
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14
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Wang Y, Wan B, Huang J, Clarke PBS. Effects of nicotine, nornicotine and cotinine, alone or in combination, on locomotor activity and ultrasonic vocalization emission in adult rats. Psychopharmacology (Berl) 2020; 237:2809-2822. [PMID: 32556369 DOI: 10.1007/s00213-020-05574-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/31/2020] [Indexed: 12/20/2022]
Abstract
RATIONALE The behavioral effects of the nicotine metabolites nornicotine and cotinine have not been investigated extensively. OBJECTIVES To evaluate the effects of nicotine, cotinine, and nornicotine, given alone or in combination, on locomotor activity and emission of ultrasonic vocalizations in male adult rats. METHODS Rats were first given home cage nicotine injections to make them tolerant to the drug's locomotor depressant effects. On subsequent days, locomotor activity (LMA) and ultrasonic vocalizations were recorded in an open field, for 60 min after challenge injection, using repeated measures designs. In single-drug experiments, subjects were tested with nicotine 0.05-0.4 mg/kg, cotinine 0.03-3 mg/kg, or nornicotine 0.1-10 mg/kg. In drug-combination experiments, saline or nicotine 0.2 mg/kg challenge was preceded by cotinine (0, 0.3, 3 mg/kg) or nornicotine (0, 0.1, 0.3, 1, 3 mg/kg) injection. RESULTS High doses of nornicotine increased LMA and blunted the locomotor stimulant effect of nicotine. Less consistently, nicotine and high doses of nornicotine decreased the 50-kHz call rate, with no clear evidence of a nornicotine × nicotine interaction. Cotinine, given alone or before nicotine injection, altered neither LMA nor the call rate. No drug altered the relative prevalence of flat vs. trill 50-kHz call subtypes, except that the highest dose of nornicotine promoted flat calls over trills. No drug evoked 22-kHz calls. CONCLUSION Nornicotine can exert an acute anti-nicotine effect in vivo, as previously reported in vitro. The finding that nicotine did not detectably alter the 50-kHz call profile appears consistent with this drug's mild subjective effects in human subjects.
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Affiliation(s)
- Yufei Wang
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building Rm. 1320, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Benson Wan
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building Rm. 1320, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Jodie Huang
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building Rm. 1320, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Paul B S Clarke
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building Rm. 1320, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada.
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15
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E-Cigarette Quality Control: Impurity and Nicotine Level Analysis in Electronic Cigarette Refill Liquids. ScientificWorldJournal 2020; 2020:3050189. [PMID: 32327940 PMCID: PMC7174940 DOI: 10.1155/2020/3050189] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 03/18/2020] [Accepted: 03/23/2020] [Indexed: 11/30/2022] Open
Abstract
This work targets mainly the quality control of electronic cigarette liquids. It relies on an analytical control of a “32-product” sample made of several types of e-cigarette liquids taken from various supermarkets and tobacconist's offices in Morocco. All along this study, we made sure to check both the conformity of the nicotine level indicated in the packaging of each product and the existence of any other components inside the product, especially toxic or unknown impurities. The method used for this study is known under the name of high-performance liquid chromatography. For statistical analysis, we used Student's t-test for a single sample in order to analyze the relative differences between nicotine quantity reported in the product and the one measured during our experiment. Finally, we used linear regression test to determine the relationship between the nicotine level accuracy on the packaging and the level of toxic impurities in the products. The differences between the nicotine concentrations reported in the packages and the measured ones varied from −100% to +3.3%. The study showed that 31% of analyzed products have an accurate indication of the level of nicotine on the packaging. However, 47% of the studied products showed more than 20% difference between measure and packaging indication. In all analyzed samples, the level of impurities altered from 0 to 32.6%. Furthermore, the level of the nicotine breakdown products did not exceed 2% of the nicotine content in pretty much all of the samples. The actual nicotine content of electronic cigarette refill liquids is not always as precise as what is stated on the packaging; in addition to the level of impurities detected in several brands and that exceeds the European Pharmacopoeia standards, some may even present a risk of causing toxicological damage.
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16
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Xing H, Keshwah S, Rouchaud A, Kem WR. A Pharmacological Comparison of Two Isomeric Nicotinic Receptor Agonists: The Marine Toxin Isoanatabine and the Tobacco Alkaloid Anatabine. Mar Drugs 2020; 18:E106. [PMID: 32053997 PMCID: PMC7073524 DOI: 10.3390/md18020106] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/15/2022] Open
Abstract
Many organisms possess "secondary" compounds to avoid consumption or to immobilize prey. While the most abundant or active compounds are initially investigated, more extensive analyses reveal other "minor" compounds with distinctive properties that may also be of biomedical and pharmaceutical significance. Here, we present an initial in vitro investigation of the actions of two isomeric tetrahydropyridyl ring-containing anabasine analogs: isoanatabine, an alkaloid isolated from a marine worm, and anatabine, a relatively abundant minor alkaloid in commercial tobacco plants. Both compounds have a double bond that is distal to the piperidine ring nitrogen of anabasine. Racemic isoanatabine and anatabine were synthesized and their S- and R-enantiomers were isolated by chiral high pressure liquid chromatography (HPLC). Both isoanatabines displayed higher efficacies at α4β2 nicotinic acetylcholine receptors (nAChRs) relative to the anatabines; R-isoanatabine was most potent. Radioligand binding experiments revealed similar α4β2 nAChR binding affinities for the isoanatabines, but R-anatabine affinity was twice that of S-anatabine. While the two anatabines and S-isoanatabine were highly efficacious agonists at α7 nAChRs, R-isoanatabine was only a weak partial agonist. The four compounds share an ability to stimulate both α4β2 and α7 nAChRs, a property that may be useful in developing more efficacious drugs to treat neurodegenerative and other medical disorders.
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Affiliation(s)
| | | | | | - William R. Kem
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL 32610, USA (S.K.)
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17
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Lefever TW, Thomas BF, Kovach AL, Snyder RW, Wiley JL. Route of administration effects on nicotine discrimination in female and male mice. Drug Alcohol Depend 2019; 204:107504. [PMID: 31476643 PMCID: PMC6878166 DOI: 10.1016/j.drugalcdep.2019.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND Use of electronic cigarettes (e-cigarettes) has increased exponentially since their appearance on the U.S. market around 2007. To provide preclinical models of vaping that incorporate olfactory cues and chemosensory effects (including flavors) that play a role in human vaping behavior, the feasibility of using a modified e-cigarette device for delivery of aerosolized nicotine was examined in a nicotine discrimination procedure in mice. METHODS Adult female and male C57BL/6 mice were trained to discriminate 0.75 mg/kg subcutaneous (s.c.) nicotine from saline. After determination of a s.c. nicotine dose-effect curve, aerosolized freebase nicotine and nicotine-containing tobacco products (i.e., non-flavored and Arctic Blast e-liquids) were evaluated. RESULTS Nicotine (s.c.) dose-dependently substituted in mice of both sexes, although females showed less sensitivity and greater variability. By contrast, aerosolized nicotine, regardless of formulation, produced concentration-dependent increases up to maximum of 46-62% nicotine-associated responding. Brain nicotine concentrations for each sex were similar for s.c. 0.75 mg/kg nicotine and 30 mg/ml freebase nicotine. CONCLUSIONS Mice of both sexes readily acquired s.c. nicotine discrimination, but females showed less sensitivity. Further, all three formulations of aerosolized nicotine produced increases in nicotine-like responding in mice of each sex. However, the maximum magnitude of these increases did not engender a similar degree of substitution as s.c. 0.75 mg/kg nicotine, despite similar brain concentrations of nicotine at 30 mg/ml aerosolized nicotine. Additional research is needed for determination of the reason(s); however, results here demonstrate initial feasibility for examination of the discriminative stimulus effects of vaped drugs such as nicotine.
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Affiliation(s)
- Timothy W Lefever
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709-2194, United States
| | - Brian F Thomas
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709-2194, United States
| | - Alexander L Kovach
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709-2194, United States
| | - Rodney W Snyder
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709-2194, United States
| | - Jenny L Wiley
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709-2194, United States.
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18
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Marusich JA, Wiley JL, Silinski MAR, Thomas BF, Meredith SE, Gahl RF, Jackson KJ. Comparison of cigarette, little cigar, and waterpipe tobacco smoke condensate and e-cigarette aerosol condensate in a self-administration model. Behav Brain Res 2019; 372:112061. [PMID: 31254537 PMCID: PMC6664429 DOI: 10.1016/j.bbr.2019.112061] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 12/15/2022]
Abstract
The pharmacological effects of tobacco products are primarily mediated by nicotine; however, research suggests that several non-nicotine tobacco constituents may alter the reinforcing effects of nicotine. This study evaluated the reinforcing effects of aqueous solutions of smoke/aerosol condensate from cigarettes, little cigars, electronic cigarettes (e-cigarettes), and waterpipe tobacco in a self-administration procedure to determine if abuse liability of these tobacco products differed. Adult male Sprague-Dawley rats (n = 64 total) were trained to self-administer intravenous nicotine (30 μg/kg/infusion) on a fixed ratio 5 schedule of reinforcement. Following nicotine dose-effect assessment (1, 7.5, 15, and 30 μg/kg/infusion), rats were given access to smoke/aerosol condensate derived from their assigned tobacco product. Rats responded for smoke/aerosol condensate containing 1, 7.5, 15, and 30 μg/kg/infusion nicotine, with the ratio of nicotine:non-nicotine constituents held constant across doses for each tobacco product. Responding for nicotine or smoke/aerosol condensate was also assessed on a progressive ratio schedule of reinforcement. Cigarette, little cigar, and e-cigarette smoke/aerosol condensates shifted the nicotine dose-effect curve leftward, whereas waterpipe tobacco smoke condensate shifted the dose-effect curve rightward. Smoke/aerosol condensate from all tobacco products produced similar levels of responding compared to nicotine alone during the progressive ratio phase. Results suggest that non-nicotine constituents in cigarettes, little cigars, and e-cigarettes differentially enhance nicotine's reinforcing potency. In contrast, waterpipe tobacco blunted nicotine's reinforcing potency, suggesting that it may contain unique constituents that dampen nicotine's reinforcing effects.
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Affiliation(s)
- Julie A Marusich
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC, 27709, USA.
| | - Jenny L Wiley
- Center for Drug Discovery, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC, 27709, USA
| | - Melanie A R Silinski
- Analytical Sciences, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC, 27709, USA
| | - Brian F Thomas
- Analytical Chemistry and Pharmaceutics, RTI International, 3040 Cornwallis Rd, Research Triangle Park, NC, 27709, USA
| | - Steven E Meredith
- U.S. Food and Drug Administration, Center for Tobacco Products, 10903 New Hampshire Ave., Silver Spring, MD, 20993, USA
| | - Robert F Gahl
- U.S. Food and Drug Administration, Center for Tobacco Products, 10903 New Hampshire Ave., Silver Spring, MD, 20993, USA
| | - Kia J Jackson
- U.S. Food and Drug Administration, Center for Tobacco Products, 10903 New Hampshire Ave., Silver Spring, MD, 20993, USA
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19
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Harris AC, Muelken P, Swain Y, Palumbo M, Jain V, Goniewicz ML, Stepanov I, LeSage MG. Non-nicotine constituents in e-cigarette aerosol extract attenuate nicotine's aversive effects in adolescent rats. Drug Alcohol Depend 2019; 203:51-60. [PMID: 31404849 PMCID: PMC6941564 DOI: 10.1016/j.drugalcdep.2019.05.023] [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] [Received: 10/30/2018] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 01/05/2023]
Abstract
BACKGROUND Development of preclinical methodology for evaluating the abuse liability of electronic cigarettes (ECs) in adolescents is urgently needed to inform FDA regulation of these products. We previously reported reduced aversive effects of EC liquids containing nicotine and a range of non-nicotine constituents (e.g., propylene glycol, minor tobacco alkaloids) compared to nicotine alone in adult rats as measured using intracranial self-stimulation. The goal of this study was to compare the aversive effects of nicotine alone and EC aerosol extracts in adolescent rats as measured using conditioned taste aversion (CTA), which can be conducted during the brief adolescent period. METHODS AND RESULTS In Experiment 1, nicotine alone (1.0 or 1.5 mg/kg, s.c.) produced significant CTA in adolescent rats in a two-bottle procedure, thereby establishing a model to study the effects of EC extracts. At a nicotine dose of 1.0 mg/kg, CTA to Vuse Menthol EC extract, but not Aroma E-Juice EC extract, was attenuated compared to nicotine alone during repeated two-bottle CTA tests (Experiment 2a). At a nicotine dose of 0.5 mg/kg, CTA to Vuse Menthol EC extract did not differ from nicotine alone during the first two-bottle CTA test but extinguished more rapidly across repeated two-bottle tests (Experiment 2b). CONCLUSIONS Non-nicotine constituents in Vuse Menthol EC extracts attenuated CTA in a two-bottle procedure in adolescents. This model may be useful for anticipating the abuse liability of ECs in adolescents and for modeling FDA-mandated changes in product standards for nicotine or other constituents in ECs.
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Affiliation(s)
- Andrew C. Harris
- Department of Medicine, Hennepin Healthcare Research Institute, Minneapolis, MN, USA,Department of Medicine, University of Minnesota, Minneapolis, MN, USA,Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - Peter Muelken
- Department of Medicine, Hennepin Healthcare Research Institute, Minneapolis, MN, USA
| | - Yayi Swain
- Department of Medicine, Hennepin Healthcare Research Institute, Minneapolis, MN, USA,Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - Mary Palumbo
- Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Vipin Jain
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Maciej L. Goniewicz
- Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Mark G. LeSage
- Department of Medicine, Hennepin Healthcare Research Institute, Minneapolis, MN, USA,Department of Medicine, University of Minnesota, Minneapolis, MN, USA,Department of Psychology, University of Minnesota, Minneapolis, MN, USA
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20
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Berman ML, Bickel WK, Harris AC, LeSage MG, O'Connor RJ, Stepanov I, Shields PG, Hatsukami DK. Consortium on Methods Evaluating Tobacco: Research Tools to Inform US Food and Drug Administration Regulation of Snus. Nicotine Tob Res 2019; 20:1292-1300. [PMID: 29059363 DOI: 10.1093/ntr/ntx228] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 09/28/2017] [Indexed: 11/13/2022]
Abstract
Introduction The US Food and Drug Administration (FDA) has purview over tobacco products. To set policy, the FDA must rely on sound science, yet most existing tobacco research methods have not been designed to specifically inform regulation. The NCI and FDA-funded Consortium on Methods Evaluating Tobacco (COMET) was established to develop and assess valid and reliable methods for tobacco product evaluation. The goal of this article is to describe these assessment methods using a US manufactured "snus" as the test product. Methods In designing studies that could inform FDA regulation, COMET has taken a multidisciplinary approach that includes experimental animal models and a range of human studies that examine tobacco product appeal, addictiveness, and toxicity. This article integrates COMET's findings over the last 4 years. Results Consistency in results was observed across the various studies, lending validity to our methods. Studies showed low abuse liability for snus and low levels of consumer demand. Toxicity was less than cigarettes on some biomarkers but higher than medicinal nicotine. Conclusions Using our study methods and the convergence of results, the snus that we tested as a potential modified risk tobacco product is likely to neither result in substantial public health harm nor benefit. Implications This review describes methods that were used to assess the appeal, abuse liability, and toxicity of snus. These methods included animal, behavioral economics, consumer perception studies, and clinical trials. Across these varied methods, study results showed low abuse-liability and appeal of the snus product we tested. In several studies, demand for snus was lower than for less toxic nicotine gum. The consistency and convergence of results across a range of multi-disciplinary studies lends validity to our methods and suggests that promotion of snus as a modified risk tobacco products is unlikely to produce substantial public health benefit or harm.
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Affiliation(s)
- Micah L Berman
- College of Public Health, Ohio State University, Columbus, OH.,Moritz College of Law, Ohio State University, Columbus, OH
| | | | - Andrew C Harris
- Minneapolis Medical Research Foundation, Minneapolis, MN.,Department of Medicine, University of Minnesota, Minneapolis, MN.,Department of Psychology, University of Minnesota, Minneapolis, MN
| | - Mark G LeSage
- Minneapolis Medical Research Foundation, Minneapolis, MN.,Department of Medicine, University of Minnesota, Minneapolis, MN.,Department of Psychology, University of Minnesota, Minneapolis, MN
| | | | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN
| | - Peter G Shields
- Comprehensive Cancer Center, Ohio State University, Columbus, OH
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Glucagon-Like Peptide-1 Receptor Agonist Treatment Does Not Reduce Abuse-Related Effects of Opioid Drugs. eNeuro 2019; 6:eN-NRS-0443-18. [PMID: 31058214 PMCID: PMC6498420 DOI: 10.1523/eneuro.0443-18.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 02/19/2019] [Accepted: 02/28/2019] [Indexed: 12/29/2022] Open
Abstract
Dependence on opioids and the number of opioid overdose deaths are serious and escalating public health problems, but medication-assisted treatments for opioid addiction remain inadequate for many patients. Glucagon-like pepide-1 (GLP-1) is a gut hormone and neuropeptide with actions in peripheral tissues and in the brain, including regulation of blood glucose and food intake. GLP-1 analogs, which are approved diabetes medications, can reduce the reinforcing and rewarding effects of alcohol, cocaine, amphetamine, and nicotine in rodents. Investigations on effects of GLP-1 analogs on opioid reward and reinforcement have not been reported. We assessed the effects of the GLP-1 receptor agonist Exendin-4 (Ex4) on opioid-related behaviors in male mice, i.e., morphine-conditioned place preference (CPP), intravenous self-administration (IVSA) of the short-acting synthetic opioid remifentanil, naltrexone-precipitated morphine withdrawal, morphine analgesia (male and female mice), and locomotor activity. Ex4 treatment had no effect on morphine-induced CPP, withdrawal, or hyperlocomotion. Ex4 failed to decrease remifentanil self-administration, if anything reinforcing effects of remifentanil appeared increased in Ex4-treated mice relative to saline. Ex4 did not significantly affect analgesia. In contrast, Ex4 dose dependently decreased oral alcohol self-administration, and suppressed spontaneous locomotor activity. Taken together, Ex4 did not attenuate the addiction-related behavioral effects of opioids, indicating that GLP-1 analogs would not be useful medications in the treatment of opioid addiction. This difference between opioids and other drug classes investigated to date may shed light on the mechanism of action of GLP-1 receptor treatment in the addictive effects of alcohol, central stimulants, and nicotine.
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Rosecrans JA, Young R. Discriminative Stimulus Properties of S(-)-Nicotine: "A Drug for All Seasons". Curr Top Behav Neurosci 2019; 39:51-94. [PMID: 28391535 DOI: 10.1007/7854_2017_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
S(-)-Nicotine is the major pharmacologically active substance in tobacco and can function as an effective discriminative stimulus in both experimental animals and humans. In this model, subjects must detect and communicate the nicotine drug state versus the non-drug state. This review describes the usefulness of the procedure to study nicotine, presents a general overview of the model, and provides some relevant methodological details for the establishment of this drug as a stimulus. Once established, the (-)-nicotine stimulus can be characterized for dose response and time course effects. Moreover, tests can be conducted to determine the similarity of effects produced by test drugs to those produced by the training dose of nicotine. Such tests have shown that the stimulus effects of nicotine are stereoselective [S(-)-nicotine >R(+)-nicotine] and that other "natural" tobacco alkaloids and (-)-nicotine metabolites can produce (-)-nicotine-like effects, but these drugs are much less potent than (-)-nicotine. Stimulus antagonism tests with mecamylamine and DHβE (dihydro-β-erythroidine) indicate that the (-)-nicotine stimulus is mediated via α4β2 nicotinic acetylcholine receptors (nAChRs) in brain; dopamine systems also are likely involved. Individuals who try to cease their use of nicotine-based products are often unsuccessful. Bupropion (Zyban®) and varenicline (Chantix®) may be somewhat effective as anti-smoking medications because they probably produce stimulus effects that serve as suitable substitutes for (-)-nicotine in the individual who is motivated to quit smoking. Finally, it is proposed that future drug discrimination studies should apply the model to the issue of maintenance of abstinence from (-)-nicotine-based products.
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Affiliation(s)
- John A Rosecrans
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, P.O. Box 980613, Richmond, VA, 23298-0613, USA
| | - Richard Young
- Department of Medicinal Chemistry, Virginia Commonwealth University, 800 East Leigh Street, P.O. Box 980540, Richmond, VA, 23219-0540, USA.
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Schmidt HD, Rupprecht LE, Addy NA. Neurobiological and Neurophysiological Mechanisms Underlying Nicotine Seeking and Smoking Relapse. MOLECULAR NEUROPSYCHIATRY 2019; 4:169-189. [PMID: 30815453 PMCID: PMC6388439 DOI: 10.1159/000494799] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/23/2018] [Indexed: 12/19/2022]
Abstract
Tobacco-related morbidity and mortality continue to be a significant public health concern. Unfortunately, current FDA-approved smoking cessation pharmacotherapies have limited efficacy and are associated with high rates of relapse. Therefore, a better understanding of the neurobiological and neurophysiological mechanisms that promote smoking relapse is needed to develop novel smoking cessation medications. Here, we review preclinical studies focused on identifying the neurotransmitter and neuromodulator systems that mediate nicotine relapse, often modeled in laboratory animals using the reinstatement paradigm, as well as the plasticity-dependent neurophysiological mechanisms that facilitate nicotine reinstatement. Particular emphasis is placed on how these neuroadaptations relate to smoking relapse in humans. We also highlight a number of important gaps in our understanding of the neural mechanisms underlying nicotine reinstatement and critical future directions, which may lead toward the development of novel, target pharmacotherapies for smoking cessation.
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Affiliation(s)
- Heath D. Schmidt
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Laura E. Rupprecht
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Nii A. Addy
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA
- Interdepartmental Neuroscience Program, Yale Graduate School of Arts and Sciences, New Haven, Connecticut, USA
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24
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Harris AC, Muelken P, Haave Z, Swain Y, Smethells JR, LeSage MG. Propylene glycol, a major electronic cigarette constituent, attenuates the adverse effects of high-dose nicotine as measured by intracranial self-stimulation in rats. Drug Alcohol Depend 2018; 193:162-168. [PMID: 30384324 PMCID: PMC6278948 DOI: 10.1016/j.drugalcdep.2018.08.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/25/2018] [Accepted: 08/26/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Non-nicotine tobacco constituents may contribute to the abuse liability of tobacco products. We previously reported that electronic cigarette (EC) refill liquids containing nicotine and a range of non-nicotine constituents attenuated the anhedonic/aversive effects of nicotine in an intracranial self-stimulation (ICSS) model. The alcohol propylene glycol (PG) is a primary ingredient in these and other EC liquids, yet its abuse potential has not been established. The goal of this study was to evaluate the effects of parenteral administration of PG alone and PG combined with nicotine on ICSS in rats. METHODS AND RESULTS PG alone did not affect ICSS at concentrations up to 100%. PG (25% or 60%) did not affect nicotine's reinforcement-enhancing (ICSS threshold-decreasing) effects at low to moderate nicotine doses, but attenuated nicotine's reinforcement-attenuating/aversive (ICSS threshold-increasing) effects at a high nicotine dose. PG concentrations similar to those in EC liquid doses used in our previous studies (1% or 3%) modestly attenuated the ICSS threshold-elevating effects of a high nicotine dose. CONCLUSIONS PG attenuated elevations in ICSS thresholds induced by high-dose nicotine, which may reflect an attenuation of nicotine's acute aversive/anhedonic and/or toxic effects. PG may have contributed to the attenuated ICSS threshold-elevating effects of EC liquids reported previously. Further examination of PG in models of addiction and toxicity is needed to understand the consequences of EC use and to inform the development of EC product standards by the FDA.
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Affiliation(s)
- Andrew C Harris
- Hennepin Healthcare Research Institute, 701 Park Avenue, Minneapolis, MN USA; Departments of Medicine, University of Minnesota Medical School, Variety Club Research Center (VCRC), 401 East River Parkway, 1(st) Floor - Suite 131, Minneapolis, MN 55455, USA; Departments of Psychology, University of Minnesota Medical School, N218 Elliott Hall, 75 E River Rd, Minneapolis, MN 55455, USA.
| | - Peter Muelken
- Hennepin Healthcare Research Institute, 701 Park Avenue, Minneapolis, MN USA
| | - Zach Haave
- Hennepin Healthcare Research Institute, 701 Park Avenue, Minneapolis, MN USA; Departments of Neuroscience, University of Minnesota Medical School, 6-145 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USA
| | - Yayi Swain
- Hennepin Healthcare Research Institute, 701 Park Avenue, Minneapolis, MN USA; Departments of Psychology, University of Minnesota Medical School, N218 Elliott Hall, 75 E River Rd, Minneapolis, MN 55455, USA
| | - John R Smethells
- Hennepin Healthcare Research Institute, 701 Park Avenue, Minneapolis, MN USA; Departments of Psychiatry, University of Minnesota Medical School, Fairview Riverside West Building, 2312 S. 6th St., Floor 2, Suite F-275, Minneapolis, MN 55454, USA
| | - Mark G LeSage
- Hennepin Healthcare Research Institute, 701 Park Avenue, Minneapolis, MN USA; Departments of Medicine, University of Minnesota Medical School, Variety Club Research Center (VCRC), 401 East River Parkway, 1(st) Floor - Suite 131, Minneapolis, MN 55455, USA; Departments of Psychology, University of Minnesota Medical School, N218 Elliott Hall, 75 E River Rd, Minneapolis, MN 55455, USA
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LeSage MG, Smethells JR, Harris AC. Status and Future Directions of Preclinical Behavioral Pharmacology in Tobacco Regulatory Science. ACTA ACUST UNITED AC 2018; 18:252-274. [PMID: 30214916 DOI: 10.1037/bar0000113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Behavioral pharmacology is a branch of the experimental analysis of behavior that has had great influence in drug addiction research and policy. This paper provides an overview of recent behavioral pharmacology research in the field of tobacco regulatory science, which provides the scientific foundation for the Food and Drug Administration Center for Tobacco Products (FDA CTP) to set tobacco control policies. The rationale and aims of tobacco regulatory science are provided, including the types of preclinical operant behavioral models it deems important for assessing the abuse liability of tobacco products and their constituents. We then review literature relevant to key regulatory actions being considered by the FDA CTP, including regulations over nicotine and menthol content of cigarettes, and conclude with suggesting some directions for future research. The current era of tobacco regulatory science provides great opportunities for behavioral pharmacologists to address the leading cause of preventable death and disease worldwide.
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Affiliation(s)
- Mark G LeSage
- Department of Medicine, Minneapolis Medical Research Foundation
- Departments of Medicine, University of Minnesota
- Department of Psychology, University of Minnesota
| | - John R Smethells
- Department of Medicine, Minneapolis Medical Research Foundation
- Departments of Medicine, University of Minnesota
| | - Andrew C Harris
- Department of Medicine, Minneapolis Medical Research Foundation
- Departments of Medicine, University of Minnesota
- Department of Psychology, University of Minnesota
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26
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Smith TT, Rupprecht LE, Denlinger-Apte RL, Weeks JJ, Panas RS, Donny EC, Sved AF. Animal Research on Nicotine Reduction: Current Evidence and Research Gaps. Nicotine Tob Res 2018; 19:1005-1015. [PMID: 28379511 DOI: 10.1093/ntr/ntx077] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 03/31/2017] [Indexed: 01/21/2023]
Abstract
A mandated reduction in the nicotine content of cigarettes may improve public health by reducing the prevalence of smoking. Animal self-administration research is an important complement to clinical research on nicotine reduction. It can fill research gaps that may be difficult to address with clinical research, guide clinical researchers about variables that are likely to be important in their own research, and provide policy makers with converging evidence between clinical and preclinical studies about the potential impact of a nicotine reduction policy. Convergence between clinical and preclinical research is important, given the ease with which clinical trial participants can access nonstudy tobacco products in the current marketplace. Herein, we review contributions of preclinical animal research, with a focus on rodent self-administration, to the science of nicotine reduction. Throughout this review, we highlight areas where clinical and preclinical research converge and areas where the two differ. Preclinical research has provided data on many important topics such as the threshold for nicotine reinforcement, the likelihood of compensation, moderators of the impact of nicotine reduction, the impact of environmental stimuli on nicotine reduction, the impact of nonnicotine cigarette smoke constituents on nicotine reduction, and the impact of nicotine reduction on vulnerable populations. Special attention is paid to current research gaps including the dramatic rise in alternative tobacco products, including electronic nicotine delivery systems (ie, e-cigarettes). The evidence reviewed here will be critical for policy makers as well as clinical researchers interested in nicotine reduction. IMPLICATIONS This review will provide policy makers and clinical researchers interested in nicotine reduction with an overview of the preclinical animal research conducted on nicotine reduction and the regulatory implications of that research. The review also highlights the utility of preclinical research for research questions related to nicotine reduction.
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Affiliation(s)
- Tracy T Smith
- University of Pittsburgh Cancer Institute, Pittsburgh, PA.,Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA
| | - Laura E Rupprecht
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA
| | - Rachel L Denlinger-Apte
- Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, RI
| | - Jillian J Weeks
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA
| | - Rachel S Panas
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA
| | - Eric C Donny
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA
| | - Alan F Sved
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA.,Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA
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27
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Harris AC, Muelken P, Smethells JR, Yershova K, Stepanov I, Olson TT, Kellar KJ, LeSage MG. Effects of nicotine-containing and "nicotine-free" e-cigarette refill liquids on intracranial self-stimulation in rats. Drug Alcohol Depend 2018; 185:1-9. [PMID: 29413432 PMCID: PMC5889751 DOI: 10.1016/j.drugalcdep.2017.11.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 11/10/2017] [Accepted: 11/30/2017] [Indexed: 11/26/2022]
Abstract
BACKGROUND Animal models are needed to inform FDA regulation of electronic cigarettes (ECs) because they avoid limitations associated with human studies. We previously reported that an EC refill liquid produced less aversive/anhedonic effects at a high nicotine dose than nicotine alone as measured by elevations in intracranial self-stimulation (ICSS) thresholds, which may reflect the presence of behaviorally active non-nicotine constituents (e.g., propylene glycol) in the EC liquids. The primary objective of this study was to assess the generality of our prior ICSS findings to two additional EC liquids. We also compared effects of "nicotine-free" varieties of these EC liquids on ICSS, as well as binding affinity and/or functional activity of nicotine alone, nicotine-containing EC liquids, and "nicotine-free" EC liquids at nicotinic acetylcholine receptors (nAChRs). METHODS AND RESULTS Nicotine alone and nicotine dose-equivalent concentrations of both nicotine-containing EC liquids produced similar lowering of ICSS thresholds at low to moderate nicotine doses, indicating similar reinforcement-enhancing effects. At high nicotine doses, nicotine alone elevated ICSS thresholds (a measure of anhedonia-like behavior) while the EC liquids did not. Nicotine-containing EC liquids did not differ from nicotine alone in terms of binding affinity or functional activity at nAChRs. "Nicotine-free" EC liquids did not affect ICSS, but bound with low affinity at some (e.g., α4ß2) nAChRs. CONCLUSIONS These findings suggest that non-nicotine constituents in these EC liquids do not contribute to their reinforcement-enhancing effects. However, they may attenuate nicotine's acute aversive/anhedonic and/or toxic effects, which may moderate the abuse liability and/or toxicity of ECs.
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Affiliation(s)
- Andrew C. Harris
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN, USA,Department of Medicine, University of Minnesota, Minneapolis, MN, USA,Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - Peter Muelken
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN, USA
| | - John R. Smethells
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN, USA,Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA
| | - Katrina Yershova
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Thao Tran Olson
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, USA
| | - Kenneth J. Kellar
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, USA
| | - Mark G. LeSage
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN, USA,Department of Medicine, University of Minnesota, Minneapolis, MN, USA,Department of Psychology, University of Minnesota, Minneapolis, MN, USA
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Bunney PE, Hansen M, LeSage M. Effects of isolated tobacco alkaloids and tobacco products on deprivation-induced food intake and meal patterns in rats. Pharmacol Biochem Behav 2018; 165:45-55. [PMID: 29196096 PMCID: PMC5801111 DOI: 10.1016/j.pbb.2017.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/01/2017] [Accepted: 11/27/2017] [Indexed: 12/19/2022]
Abstract
The ability of smoking to reduce body weight serves as motivation for continued smoking. It is unclear to what extent non-nicotine constituents in cigarettes are contributing to the weight-reducing effect of smoking. The purpose of the current study was to examine the effects of nicotine and four minor tobacco alkaloids (nornicotine, cotinine, anatabine, and anabasine) on food intake, one of the key regulators of body weight. In addition, a smokeless tobacco extract (STE) and e-cigarette (EC) refill liquid were used to model the effects of actual tobacco product exposure on food intake. Male Holztman rats were trained to lever press for food pellets during daily 2h sessions in operant chambers. In Experiment 1, the effects of subcutaneous injections of saline, nicotine (0.25-1.00mg/kg), nornicotine (0.50-6.00mg/kg), cotinine (1.00-100.00mg/kg), anatabine (0.25-3.00mg/kg), and anabasine (0.50-4.00mg/kg) were assessed. In Experiment 2, rats from Experiment 1 were used to examine the effects of nicotine, STE, and EC liquid. All alkaloids, except cotinine, produced a dose-dependent reduction in overall food intake. The highest doses of all drugs significantly reduced latency and response rate to obtain the first pellet. At some doses, nicotine, anatabine, and nornicotine reduced food intake within the first 45min without compensatory increases in intake later in the session. STE and EC liquid produced dose dependent decreases in food intake similar to nicotine alone. These data suggest that minor tobacco alkaloids have appetite suppressant effects and warrant further investigation into their effects on body weight, energy intake, and energy expenditure under free-feeding conditions. However, findings with STE and EC liquid suggest that nicotine is the primary constituent in these products to affect food intake, whereas levels of minor alkaloids in these products may be too low to influence food intake.
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Affiliation(s)
- Patricia E Bunney
- Department of Medicine, Minneapolis Medical Research Foundation, 701 Park Ave., Minneapolis, MN 55415, United States; Department of Medicine, University of Minnesota School of Medicine, 420 Delaware St. SE, Minneapolis, MN 55455, United States.
| | - Mylissa Hansen
- Department of Medicine, Minneapolis Medical Research Foundation, 701 Park Ave., Minneapolis, MN 55415, United States
| | - Mark LeSage
- Department of Medicine, Minneapolis Medical Research Foundation, 701 Park Ave., Minneapolis, MN 55415, United States; Department of Medicine, University of Minnesota School of Medicine, 420 Delaware St. SE, Minneapolis, MN 55455, United States; Department of Psychology, University of Minnesota, N218 Elliot Hall, 75 E River Rd., Minneapolis, MN 55455, United States
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29
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Elhassan S, Bagdas D, Damaj MI. Effects of Nicotine Metabolites on Nicotine Withdrawal Behaviors in Mice. Nicotine Tob Res 2017; 19:763-766. [PMID: 28199726 DOI: 10.1093/ntr/ntx045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 02/07/2017] [Indexed: 12/11/2022]
Abstract
Introduction Rodent studies suggest that nicotine metabolites and minor tobacco alkaloids such as nornicotine and cotinine may promote cigarette smoking by enhancing nicotine rewarding and reinforcing effects. However, there is little information on the effects of these minor tobacco alkaloids on nicotine withdrawal. The present studies were conducted to determine whether the minor tobacco alkaloids nornicotine and cotinine exhibit nicotine-like behavioral effects in a mouse model of spontaneous nicotine withdrawal. Methods Mice were infused with nicotine or saline for 14 days. Experiments were conducted on day 15, 18-24 hours after minipump removal. Ten minutes prior to testing, nicotine-dependent ICR male mice received an acute injection of nicotine (0.05 and 0.5 mg/kg), nornicotine (2.5 and 25 mg/kg), or cotinine (5 and 50 mg/kg) to determine effects on somatic signs, anxiety-like behaviors, and hyperalgesia spontaneous signs of withdrawal. Results Nicotine and the minor tobacco alkaloid nornicotine, but not cotinine, produced dose-dependent reversal of nicotine withdrawal signs in the mouse. Implications The minor tobacco alkaloid and nicotine metabolite nornicotine at high doses have nicotinic like effects that may contribute to tobacco consumption and dependence.
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Affiliation(s)
- Sagi Elhassan
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA
| | - Deniz Bagdas
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA.,Experimental Animals Breeding and Research Center, Faculty of Medicine, Uludag University, Bursa, Turkey
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA
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Marusich JA, Darna M, Wilson AG, Denehy ED, Ebben A, Deaciuc AG, Dwoskin LP, Bardo MT, Lefever TW, Wiley JL, Reissig CJ, Jackson KJ. Tobacco's minor alkaloids: Effects on place conditioning and nucleus accumbens dopamine release in adult and adolescent rats. Eur J Pharmacol 2017; 814:196-206. [PMID: 28844873 PMCID: PMC6563910 DOI: 10.1016/j.ejphar.2017.08.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/18/2017] [Accepted: 08/23/2017] [Indexed: 12/23/2022]
Abstract
Tobacco products are some of the most commonly used psychoactive drugs worldwide. Besides nicotine, alkaloids in tobacco include cotinine, myosmine, and anatabine. Scientific investigation of these constituents and their contribution to tobacco dependence is less well developed than for nicotine. The present study evaluated the nucleus accumbens dopamine-releasing properties and rewarding and/or aversive properties of nicotine (0.2-0.8mg/kg), cotinine (0.5-5.0mg/kg), anatabine (0.5-5.0mg/kg), and myosmine (5.0-20.0mg/kg) through in vivo microdialysis and place conditioning, respectively, in adult and adolescent male rats. Nicotine increased dopamine release at both ages, and anatabine and myosmine increased dopamine release in adults, but not adolescents. The dopamine release results were not related to place conditioning, as nicotine and cotinine had no effect on place conditioning, whereas anatabine and myosmine produced aversion in both ages. While the nucleus accumbens shell is hypothesized to play a role in strengthening drug-context associations following initiation of drug use, it may have little involvement in the motivational effects of tobacco constituents once these associations have been acquired. Effects of myosmine and anatabine on dopamine release may require a fully developed dopamine system, since no effects of these tobacco alkaloids were observed during adolescence. In summary, while anatabine and myosmine-induced dopamine release in nucleus accumbens may play a role in tobacco dependence in adults, the nature of that role remains to be elucidated.
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Affiliation(s)
- Julie A Marusich
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA.
| | - Mahesh Darna
- College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA
| | - A George Wilson
- Center for Drug Abuse Research Translation, University of Kentucky, Lexington, KY 40536-0509, USA
| | - Emily D Denehy
- Center for Drug Abuse Research Translation, University of Kentucky, Lexington, KY 40536-0509, USA
| | - Amanda Ebben
- College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA
| | - Agripina G Deaciuc
- College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA
| | - Linda P Dwoskin
- College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA
| | - Michael T Bardo
- Center for Drug Abuse Research Translation, University of Kentucky, Lexington, KY 40536-0509, USA
| | - Timothy W Lefever
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA
| | - Jenny L Wiley
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA
| | - Chad J Reissig
- US Food and Drug Administration, Center for Tobacco Products, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Kia J Jackson
- US Food and Drug Administration, Center for Tobacco Products, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
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31
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Lefever TW, Lee YO, Kovach AL, Silinski MA, Marusich JA, Thomas BF, Wiley JL. Delivery of nicotine aerosol to mice via a modified electronic cigarette device. Drug Alcohol Depend 2017; 172:80-87. [PMID: 28157590 PMCID: PMC5327853 DOI: 10.1016/j.drugalcdep.2016.12.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/21/2016] [Accepted: 12/04/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND Although both men and women use e-cigarettes, most preclinical nicotine research has focused on its effects in male rodents following injection. The goals of the present study were to develop an effective e-cigarette nicotine delivery system, to compare results to those obtained after subcutaneous (s.c.) injection, and to examine sex differences in the model. METHODS Hypothermia and locomotor suppression were assessed following aerosol exposure or s.c. injection with nicotine in female and male mice. Subsequently, plasma and brain concentrations of nicotine and cotinine were measured. RESULTS Passive exposure to nicotine aerosol produced concentration-dependent and mecamylamine reversible hypothermic and locomotor suppressant effects in female and male mice, as did s.c. nicotine injection. In plasma and brain, nicotine and cotinine concentrations showed dose/concentration-dependent increases in both sexes following each route of administration. Sex differences in nicotine-induced hypothermia were dependent upon route of administration, with females showing greater hypothermia following aerosol exposure and males showing greater hypothermia following injection. In contrast, when they occurred, sex differences in nicotine and cotinine levels in brain and plasma consistently showed greater concentrations in females than males, regardless of route of administration. DISCUSSION In summary, the e-cigarette exposure device described herein was used successfully to deliver pharmacologically active doses of nicotine to female and male mice. Further, plasma nicotine concentrations following exposure were similar to those after s.c. injection with nicotine and within the range observed in human smokers. Future research on vaped products can be strengthened by inclusion of translationally relevant routes of administration.
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Affiliation(s)
- Timothy W. Lefever
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | - Youn O.K. Lee
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | | | | | - Julie A. Marusich
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | - Brian F. Thomas
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | - Jenny L. Wiley
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
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32
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Henningfield JE, Smith TT, Kleykamp BA, Fant RV, Donny EC. Nicotine self-administration research: the legacy of Steven R. Goldberg and implications for regulation, health policy, and research. Psychopharmacology (Berl) 2016; 233:3829-3848. [PMID: 27766371 PMCID: PMC5588156 DOI: 10.1007/s00213-016-4441-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 09/15/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND RATIONALE Steven R. Goldberg was a pioneering behavioral pharmacologist whose intravenous drug self-administration studies advanced the understanding of conditioned stimuli and schedules of reinforcement as determinants of pattern and persistence of drug-seeking behavior, and in particular, the importance of nicotine in tobacco use. His passing in 2014 led to invitations to contribute articles to psychopharmacology dedicated to his work. OBJECTIVES The objectives of this review are to summarize and put into historical perspective Goldberg's contributions to elucidate the reinforcing effects of nicotine and to summarize the implications of his research for medication development, tobacco regulation, and potential tobacco control policy options. This includes a review of intravenous nicotine self-administration research from the 1960s to 2016. RESULTS Goldberg's application of behavioral pharmacology methods to investigate nicotine reinforcement and the influence of schedule of reinforcement and conditioned stimuli on nicotine administration contributed to the conclusions of the US National Institute on Drug Abuse, and the Surgeon General, that nicotine met the criteria as a dependence-producing drug and cigarette smoking as a prototypic drug dependency or "addiction." Equally important, this work has been systematically extended to other species and applied to address a range of factors relevant to tobacco use, medication development, regulation, and public health policy. CONCLUSIONS Steven R. Goldberg was a pioneering scientist whose systematic application of the science of behavioral pharmacology advanced the understanding of tobacco and nicotine use and contributed to the scientific foundation for tobacco product regulation and potential public health tobacco control policy development.
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Affiliation(s)
- Jack E Henningfield
- Pinney Associates, 4800 Montgomery Lane, Suite 400, Bethesda, MD, 20814, USA.
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Tracy T Smith
- University of Pittsburgh Cancer Institute, 4120 Sennott Square, 210 S. Bouquet Street, Pittsburgh, PA, 15260, USA
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, 4120 Sennott Square, 210 S. Bouquet Street, Pittsburgh, PA, 15260, USA
| | - Bethea A Kleykamp
- Pinney Associates, 4800 Montgomery Lane, Suite 400, Bethesda, MD, 20814, USA
| | - Reginald V Fant
- Pinney Associates, 4800 Montgomery Lane, Suite 400, Bethesda, MD, 20814, USA
| | - Eric C Donny
- Department of Psychology, University of Pittsburgh, 210 S. Bouquet Street, Pittsburgh, PA, 15260, USA
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Sørensen G, Caine SB, Thomsen M. Effects of the GLP-1 Agonist Exendin-4 on Intravenous Ethanol Self-Administration in Mice. Alcohol Clin Exp Res 2016; 40:2247-2252. [PMID: 27579999 PMCID: PMC5048549 DOI: 10.1111/acer.13199] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 07/28/2016] [Indexed: 12/15/2022]
Abstract
BACKGROUND Glucagon-like peptide 1 (GLP-1) receptor agonists have been shown to decrease ethanol (EtOH) drinking in rodent assays. The GLP-1 system also powerfully modulates food and fluid intake, gastrointestinal functions, and metabolism. To begin to understand the neurobiological mechanisms by which GLP-1 receptor ligands may be able to control EtOH intake, it is important to ascertain whether they can modulate the direct reinforcing effects of EtOH, without the confound of effects on ingestive behaviors generally. METHODS We trained experimentally naïve, free-fed C57BL/6J mice to self-administer EtOH intravenously. Once stable EtOH intake was acquired, we tested the effect of acute pretreatment with the GLP-1 receptor agonist Exendin-4. Effect of Exendin-4 on operant behavior reinforced by a palatable liquid food was similarly evaluated as a control. RESULTS Intravenous EtOH functioned as a positive reinforcer in over half the mice tested. In mice that acquired self-administration, EtOH intake was high, indeed, reaching toxic doses; 3.2 μg/kg Exendin-4 decreased intravenous EtOH intake by at least 70%, but had no significant effect on food-maintained operant responding. CONCLUSIONS This experiment produced 2 main conclusions. First, although technically challenging and yielding only moderate throughput, the intravenous self-administration procedure in mice is feasible, and sensitive to pharmacological manipulations. Second, GLP-1 receptor agonists can powerfully attenuate voluntary EtOH intake by directly modulating the reinforcing effects of EtOH. These findings support the potential usefulness of GLP-1 receptor ligands in the treatment of alcohol use disorder.
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Affiliation(s)
- Gunnar Sørensen
- Alcohol and Drug Abuse Research Center, McLean Hospital/Harvard Medical School, Belmont, Massachusetts.
| | - S Barak Caine
- Alcohol and Drug Abuse Research Center, McLean Hospital/Harvard Medical School, Belmont, Massachusetts
| | - Morgane Thomsen
- Alcohol and Drug Abuse Research Center, McLean Hospital/Harvard Medical School, Belmont, Massachusetts
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Kaczorowski RL, Markman S. Nectar alkaloids of tree tobacco can reduce Palestine sunbird foraging performance in a colour discrimination task. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.05.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Lee JY, Choi MJ, Choe ES, Lee YJ, Seo JW, Yoon SS. Differential discriminative-stimulus effects of cigarette smoke condensate and nicotine in nicotine-discriminating rats. Behav Brain Res 2016; 306:197-201. [DOI: 10.1016/j.bbr.2016.03.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/09/2016] [Accepted: 03/16/2016] [Indexed: 01/14/2023]
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Desai RI, Sullivan KA, Kohut SJ, Bergman J. Influence of experimental history on nicotine self-administration in squirrel monkeys. Psychopharmacology (Berl) 2016; 233:2253-63. [PMID: 27040402 DOI: 10.1007/s00213-016-4274-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/14/2016] [Indexed: 12/14/2022]
Abstract
RATIONALE Methods for establishing robust long-term self-administration of intravenous (i.v.) nicotine, the primary psychoactive agent in tobacco, are not well-established in laboratory animals. OBJECTIVE Here, we examine the use of a fading procedure to establish robust and consistent i.v. nicotine self-administration under second-order schedule conditions in squirrel monkeys. METHODS First, self-administration behavior was developed in two groups of male squirrel monkeys using a second-order fixed-interval 5-min schedule with fixed-ratio 5 units (FI 5-min (FR5: S)). Comparable performances were maintained by i.v. cocaine (0.032 mg/kg/injection (inj); group A, n = 3) and the combination of food delivery (20-30 % condensed milk) and 0.01 mg/kg/inj i.v. nicotine (group B, n = 3). Subsequently, the concentration of condensed milk was gradually reduced to zero in the second group and self-administration behavior was maintained by i.v. nicotine alone. Next, self-administration of a range of doses of i.v. nicotine (0.001-0.032 mg/kg/inj) and, in additional experiments, the minor tobacco alkaloid anatabine (0.01-0.18 mg/kg/inj) was studied in both groups. RESULTS Results show that nicotine and anatabine had reinforcing effects in both groups. However, optimal doses of nicotine and anatabine maintained significantly higher rates of i.v. self-administration behavior in subjects trained with the fading procedure than in subjects provided with a history of cocaine-maintained responding. CONCLUSION These results illustrate conditions under which robust i.v. nicotine self-administration can be established in squirrel monkeys and the influence of prior experimental history in the expression of reinforcing effects of nicotine and anatabine.
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Affiliation(s)
- Rajeev I Desai
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA.
| | - Katherine A Sullivan
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA
| | - Stephen J Kohut
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA
| | - Jack Bergman
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA
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Desai RI, Doyle MR, Withey SL, Bergman J. Nicotinic effects of tobacco smoke constituents in nonhuman primates. Psychopharmacology (Berl) 2016; 233:1779-89. [PMID: 26892379 DOI: 10.1007/s00213-016-4238-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/04/2016] [Indexed: 12/25/2022]
Abstract
RATIONALE Recent studies in rodents suggest that non-nicotine constituents of tobacco smoke (e.g., minor tobacco alkaloids) may promote tobacco consumption-either through their own pharmacological effects or by augmenting the effects of nicotine. However, there is scant information on the behavioral pharmacology of minor tobacco alkaloids in primate species. OBJECTIVE The present studies were conducted to determine whether the minor tobacco alkaloids nornicotine, anabasine, anatabine, myosmine, and cotinine exhibit nicotine-like behavioral effects in squirrel monkeys. METHODS Initial experiments were conducted to determine the effects of nicotine (0.032-1.0 mg/kg) and the minor tobacco alkaloids nornicotine (1-1.8 mg/kg), anabasine (0.1-1.0 mg/kg), anatabine (10-32 mg/kg), myosmine (0.32-1.8 mg/kg), and cotinine (10-180 mg/kg) on food-maintained performance (n = 4). Next, the ability of tobacco alkaloids to substitute for the α4β2-selective nicotinic agonist (+)-epibatidine in drug discrimination experiments was evaluated in a separate group of monkeys (n = 4). RESULTS Results show that nicotine and each minor tobacco alkaloid except cotinine (a) produced dose-related decreases in food-maintained responding; (b) substituted for (+)-epibatidine and, in additional experiments, produced additive effects when combined with nicotine; (c) induced emesis or tremor at doses that reduced food-maintained responding and had (+)-epibatidine-like discriminative-stimulus effects; and (d) based on correlation with reported receptor binding affinities, likely produced their behavioral effects through α4β2 receptor mechanisms. CONCLUSION Selected minor tobacco alkaloids have nicotinic-like effects that may contribute to tobacco consumption and addiction.
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Affiliation(s)
- Rajeev I Desai
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA.
| | - Michelle R Doyle
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA
| | - Sarah L Withey
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA
| | - Jack Bergman
- Preclinical Pharmacology Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA
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Abstract
BACKGROUND Smoking cessation aids appear to be limited in their ability to prevent craving triggered by exposure to smoking-associated stimuli; however, the extent to which cue-induced cravings persist following denicotinized or nicotine-containing tobacco smoking is not known. METHODS Thirty (17 male) ⩾12-hour abstinent dependent smokers completed two sessions during which they smoked a nicotine-containing or denicotinized cigarette. Instructions regarding the nicotine content of the cigarette varied across sessions, and all participants were exposed to a neutral cue followed by a smoking cue after cigarette consumption. Craving was assessed before and after cigarette consumption and cue exposure. RESULTS Reduced intentions to smoke were associated with both nicotine expectancy (p<0.05) and nicotine administration (p<0.01), while reduced withdrawal-related craving was uniquely associated with nicotine administration (p<0.05). Smoking-associated stimuli increased craving regardless of nicotine expectancy or administration (p-values<0.001). CONCLUSIONS While both nicotine pharmacology and expectancy appear to contribute to craving reduction associated with acute tobacco smoking, neither smoking-related nicotine administration nor expectation prevents increases in craving following exposure to smoking-associated stimuli. These findings suggest that cue-induced craving may be resistant to various pharmacological and psychological interventions.
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Affiliation(s)
- Hera E Schlagintweit
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Sean P Barrett
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
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van de Nobelen S, Kienhuis AS, Talhout R. An Inventory of Methods for the Assessment of Additive Increased Addictiveness of Tobacco Products. Nicotine Tob Res 2016; 18:1546-55. [PMID: 26817491 PMCID: PMC4902882 DOI: 10.1093/ntr/ntw002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 12/30/2015] [Indexed: 01/01/2023]
Abstract
BACKGROUND Cigarettes and other forms of tobacco contain the addictive drug nicotine. Other components, either naturally occurring in tobacco or additives that are intentionally added during the manufacturing process, may add to the addictiveness of tobacco products. As such, these components can make cigarette smokers more easily and heavily dependent.Efforts to regulate tobacco product dependence are emerging globally. Additives that increase tobacco dependence will be prohibited under the new European Tobacco Product Directive. OBJECTIVE This article provides guidelines and recommendations for developing a regulatory strategy for assessment of increase in tobacco dependence due to additives. Relevant scientific literature is summarized and criteria and experimental studies that can define increased dependence of tobacco products are described. CONCLUSIONS Natural tobacco smoke is a very complex matrix of components, therefore analysis of the contribution of an additive or a combination of additives to the level of dependence on this product is challenging. We propose to combine different type of studies analyzing overall tobacco product dependence potential and the functioning of additives in relation to nicotine. By using a combination of techniques, changes associated with nicotine dependence such as behavioral, physiological, and neurochemical alterations can be examined to provide sufficient information.Research needs and knowledge gaps will be discussed and recommendations will be made to translate current knowledge into legislation. As such, this article aids in implementation of the Tobacco Product Directive, as well as help enable regulators and researchers worldwide to develop standards to reduce dependence on tobacco products. IMPLICATIONS This article provides an overall view on how to assess tobacco product constituents for their potential contribution to use and dependence. It provides guidelines that help enable regulators worldwide to develop standards to reduce dependence on tobacco products and guide researches to set research priorities on this topic.
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Affiliation(s)
- Suzanne van de Nobelen
- Center for Health Protection (GZB), National Institute of Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - Anne S Kienhuis
- Center for Health Protection (GZB), National Institute of Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - Reinskje Talhout
- Center for Health Protection (GZB), National Institute of Public Health and Environment (RIVM), Bilthoven, The Netherlands
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Smith TT, Schaff MB, Rupprecht LE, Schassburger RL, Buffalari DM, Murphy SE, Sved AF, Donny EC. Effects of MAO inhibition and a combination of minor alkaloids, β-carbolines, and acetaldehyde on nicotine self-administration in adult male rats. Drug Alcohol Depend 2015; 155:243-52. [PMID: 26257022 PMCID: PMC4581969 DOI: 10.1016/j.drugalcdep.2015.07.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 07/02/2015] [Accepted: 07/02/2015] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Although nicotine is the primary reinforcing constituent in cigarettes, there is evidence that other constituents in cigarette smoke may interact with nicotine to reinforce smoking behavior. METHODS The present experiments investigated whether a novel combination of these cigarette smoke constituents would increase nicotine self-administration in adult male rats. The constituents included five minor alkaloids (anabasine, nornicotine, cotinine, myosmine, and anatabine), two β-carbolines (harman and norharman), and acetaldehyde. All doses were indexed to be proportional to concentrations in cigarette smoke given a standard dose of nicotine used in rodent self-administration, or ten times higher than this standard. To model MAO inhibition seen in chronic smokers, some groups received separate injections of tranylcypromine prior to each self-administration session. RESULTS Tranylcypromine increased low-dose nicotine self-administration independent of other smoke constituents, which had no effect on self-administration behavior. The effect of tranylcypromine was confirmed across a large range of reinforcement schedules. The effect of tranylcypromine on low-dose nicotine self-administration was observed regardless of whether the injection was delivered 1-h or 23-h prior to the self-administration session, consistent with the interpretation that MAO inhibition was responsible for the increase in self-administration, instead of acute off-target effects. CONCLUSIONS These data suggest that this cocktail of constituents does not significantly alter the primary reinforcing effects of nicotine, but constituents that inhibit MAO may increase the primary reinforcing effects of nicotine, especially at low doses.
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Thorburn LP, Adler LS, Irwin RE, Palmer-Young EC. Variable effects of nicotine, anabasine, and their interactions on parasitized bumble bees. F1000Res 2015; 4:880. [PMID: 26998225 PMCID: PMC4786900 DOI: 10.12688/f1000research.6870.2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/11/2015] [Indexed: 11/20/2022] Open
Abstract
Secondary metabolites in floral nectar have been shown to reduce parasite load in two common bumble bee species. Previous studies on the effects of nectar secondary metabolites on parasitized bees have focused on single compounds in isolation; however, in nature, bees are simultaneously exposed to multiple compounds. We tested for interactions between the effects of two alkaloids found in the nectar of Nicotiana spp. plants, nicotine and anabasine, on parasite load and mortality in bumble bees ( Bombus impatiens) infected with the intestinal parasite Crithidia bombi. Adult worker bees inoculated with C. bombi were fed nicotine and anabasine diet treatments in a factorial design, resulting in four nectar treatment combinations: 2 ppm nicotine, 5 ppm anabasine, 2ppm nicotine and 5 ppm anabasine together, or a control alkaloid-free solution. We conducted the experiment twice: first, with bees incubated under variable environmental conditions ('Variable'; temperatures varied from 10-35°C with ambient lighting); and second, under carefully controlled environmental conditions ('Stable'; 27°C incubator, constant darkness). In 'Variable', each alkaloid alone significantly decreased parasite loads, but this effect was not realized with the alkaloids in combination, suggesting an antagonistic interaction. Nicotine but not anabasine significantly increased mortality, and the two compounds had no interactive effects on mortality. In 'Stable', nicotine significantly increased parasite loads, the opposite of its effect in 'Variable'. While not significant, the relationship between anabasine and parasite loads was also positive. Interactive effects between the two alkaloids on parasite load were non-significant, but the pattern of antagonistic interaction was similar to that in the variable experiment. Neither alkaloid, nor their interaction, significantly affected mortality under controlled conditions. Our results do not indicate synergy between Nicotiana nectar alkaloids; however, they do suggest a complex interaction between secondary metabolites, parasites, and environmental variables, in which secondary metabolites can be either toxic or medicinal depending on context.
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Affiliation(s)
- Lukas P Thorburn
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, USA
| | - Lynn S Adler
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, USA
| | - Rebecca E Irwin
- Department of Biology, Dartmouth College Hanover, New Hampshire, USA; Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, USA
| | - Evan C Palmer-Young
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, USA
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Harris AC, Tally L, Muelken P, Banal A, Schmidt CE, Cao Q, LeSage MG. Effects of nicotine and minor tobacco alkaloids on intracranial-self-stimulation in rats. Drug Alcohol Depend 2015; 153:330-4. [PMID: 26094184 PMCID: PMC4509975 DOI: 10.1016/j.drugalcdep.2015.06.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/01/2015] [Accepted: 06/02/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND While nicotine is the primary addictive compound in tobacco, other tobacco constituents including minor alkaloids (e.g., nornicotine, anabasine) may also contribute to tobacco addiction by mimicking or enhancing the effects of nicotine. Further evaluating the behavioral effects of minor alkaloids is essential for understanding their impact on tobacco addiction and informing development of tobacco product standards by the FDA. METHODS This study compared the addiction-related effects of nicotine and the minor alkaloids nornicotine, anabasine, myosmine, anatabine, and cotinine on intracranial self-stimulation (ICSS) thresholds in rats. RESULTS Acute injection of nicotine produced reinforcement-enhancing (ICSS threshold-decreasing) effects at low to moderate doses, and reinforcement-attenuating/aversive (ICSS threshold-increasing) effects at high doses. Nornicotine and anabasine produced similar biphasic effects on ICSS thresholds, although with lower potency compared to nicotine. Myosmine only elevated ICSS thresholds at relatively high doses, while anatabine and cotinine did not influence ICSS thresholds at any dose. None of the alkaloids significantly influenced ICSS response latencies, indicating a lack of nonspecific motoric effects. CONCLUSIONS These findings indicate that some minor tobacco alkaloids can either fully (nornicotine, anabasine) or partially (myosmine) mimic nicotine's addiction-related effects on ICSS, albeit at reduced potency. These findings emphasize the need for further study of the abuse potential of minor alkaloids, including evaluation of their effects when combined with nicotine and other tobacco constituents to better simulate tobacco exposure in humans. Such work is essential for informing FDA regulation of tobacco products and could also lead to the development of novel pharmacotherapies for tobacco addiction.
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Affiliation(s)
- Andrew C. Harris
- Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota Medical School, Minneapolis, MN,Department of Psychology, University of Minnesota, Minneapolis, MN
| | - Laura Tally
- Minneapolis Medical Research Foundation, Minneapolis, MN
| | - Peter Muelken
- Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN
| | - Andrew Banal
- Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Psychology, University of Minnesota, Minneapolis, MN
| | - Clare E. Schmidt
- Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Neuroscience, University of Minnesota, Minneapolis, MN
| | - Qing Cao
- Masonic Cancer Center Biostatistics and Bioinformatics Core, University of Minnesota, Minneapolis, MN
| | - Mark G. LeSage
- Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota Medical School, Minneapolis, MN,Department of Psychology, University of Minnesota, Minneapolis, MN
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Wiley JL, Marusich JA, Thomas BF, Jackson KJ. Determination of behaviorally effective tobacco constituent doses in rats. Nicotine Tob Res 2015; 17:368-71. [PMID: 25271188 PMCID: PMC5479508 DOI: 10.1093/ntr/ntu194] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/10/2014] [Indexed: 11/12/2022]
Abstract
INTRODUCTION While nicotine has been established as the primary addictive drug that promotes tobacco use, recent peer-reviewed studies suggest that tobacco smoke contains additional chemical constituents that may have addictive potential. Additional research is necessary to determine the addictive potential of these tobacco constituents individually and in combination with tobacco smoke condensate; however, the behaviorally effective constituent doses necessary to conduct such studies are unclear. The primary objective of this study was to conduct behavioral studies in adult rats to determine the relevant behaviorally effective doses of the tobacco constituents, cotinine, myosmine, and anatabine to be used in future studies assessing the addictive potential of these compounds. METHODS Separate groups of adult male Sprague Dawley rats were treated with vehicle, nicotine, or various doses of cotinine, mysomine, or anatabine. Effects on locomotor activity were measured in 10-min bins for 60min. RESULTS Nicotine (0.8mg/kg) produced a biphasic effect on locomotor activity, with hypoactivity during the first 10min and hyperactivity at 40-50min. In contrast, cotinine (0.1mg/kg) and myosmine (10-50mg/kg) decreased activity without a later increase. Anatabine significantly increased locomotor activity at 1mg/kg, but decreased it at 10mg/kg. Prominent effects on overt behavior were observed at anatabine doses of 10mg/kg and above. CONCLUSION Nicotine, cotinine, myosmine, and anatabine produced distinct time- and dose-dependent patterns of effects on locomotor activity. Results from the study will aid in the selection of relevant doses for future studies assessing the addictive potential of these non-nicotine tobacco constituents.
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Affiliation(s)
| | | | | | - Kia J Jackson
- Office of Science, Center for Tobacco Products, U.S. Food and Drug Administration, Silver Spring, MD
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Goodwin AK, Hiranita T, Paule MG. The Reinforcing Effects of Nicotine in Humans and Nonhuman Primates: A Review of Intravenous Self-Administration Evidence and Future Directions for Research. Nicotine Tob Res 2015; 17:1297-310. [PMID: 25673111 DOI: 10.1093/ntr/ntv002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 01/02/2015] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Cigarette smoking is largely driven by the reinforcing properties of nicotine. Intravenous (IV) self-administration procedures are the gold standard for investigating the reinforcing effects of psychoactive drugs. The goal of this review was to examine the results of published investigations of the reinforcing effects of nicotine measured using IV self-administration procedures in humans and nonhuman primates. RESULTS The body of literature using nonhuman primate subjects indicates nicotine functions as a positive reinforcer when available for self-administration via IV catheters. However, it can also be difficult to establish IV nicotine self-administration in nonhuman primates and sometimes supplemental strategies have been required (e.g., priming injections or food deprivation) before subjects acquire the behavior. Although the body of literature using human subjects is limited, the evidence indicates nicotine functions as a reinforcer via the IV route of administration in adult cigarette smokers. Rates of nicotine self-injection can be variable across subjects and responding is sometimes inconsistent across sessions in both humans and nonhuman primates. CONCLUSIONS The Family Smoking Prevention and Tobacco Control Act, enacted in 2009, gave the Food and Drug Administration regulatory authority over the manufacture, marketing, and distribution of tobacco products. Research examining the threshold reinforcing doses for initiation and maintenance of nicotine self-administration, comparisons of the reinforcing effects of nicotine in adolescent versus adult subjects, investigations of gender differences in the reinforcing effects of nicotine, and studies of the abuse liability of non-nicotine tobacco product constituents and their ability to alter the reinforcing effects of nicotine will inform potential tobacco regulatory actions.
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Affiliation(s)
- Amy K Goodwin
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR
| | - Takato Hiranita
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR
| | - Merle G Paule
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR
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Rupprecht LE, Smith TT, Schassburger RL, Buffalari DM, Sved AF, Donny EC. Behavioral mechanisms underlying nicotine reinforcement. Curr Top Behav Neurosci 2015; 24:19-53. [PMID: 25638333 PMCID: PMC4536896 DOI: 10.1007/978-3-319-13482-6_2] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cigarette smoking is the leading cause of preventable deaths worldwide, and nicotine, the primary psychoactive constituent in tobacco, drives sustained use. The behavioral actions of nicotine are complex and extend well beyond the actions of the drug as a primary reinforcer. Stimuli that are consistently paired with nicotine can, through associative learning, take on reinforcing properties as conditioned stimuli. These conditioned stimuli can then impact the rate and probability of behavior and even function as conditioning reinforcers that maintain behavior in the absence of nicotine. Nicotine can also act as a conditioned stimulus (CS), predicting the delivery of other reinforcers, which may allow nicotine to acquire value as a conditioned reinforcer. These associative effects, establishing non-nicotine stimuli as conditioned stimuli with discriminative stimulus and conditioned reinforcing properties as well as establishing nicotine as a CS, are predicted by basic conditioning principles. However, nicotine can also act non-associatively. Nicotine directly enhances the reinforcing efficacy of other reinforcing stimuli in the environment, an effect that does not require a temporal or predictive relationship between nicotine and either the stimulus or the behavior. Hence, the reinforcing actions of nicotine stem both from the primary reinforcing actions of the drug (and the subsequent associative learning effects) as well as the reinforcement enhancement action of nicotine which is non-associative in nature. Gaining a better understanding of how nicotine impacts behavior will allow for maximally effective tobacco control efforts aimed at reducing the harm associated with tobacco use by reducing and/or treating its addictiveness.
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Affiliation(s)
| | | | | | | | - Alan F. Sved
- Department of Neuroscience, University of Pittsburgh
- Department of Psychology, University of Pittsburgh
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Dar R, Barrett SP. The effects of beliefs regarding drug assignment in experimental and field studies of nicotine delivery devices: a review. J Psychopharmacol 2014; 28:1071-9. [PMID: 25253274 DOI: 10.1177/0269881114548295] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The placebo effect of a psychoactive drug can be defined as the effect of expecting the drug in the absence of its pharmacological actions. As nicotine is widely believed to be the primary factor driving cigarette smoking, smokers are likely to expect nicotine to alleviate craving and withdrawal. The present review examines the extent to which any observed effects of nicotine, and especially its craving- and withdrawal-reducing effects, can be attributed to placebo. We begin by reviewing studies that examined the placebo effects of nicotine in the laboratory and follow with a review of potential placebo effects that are typically not controlled in placebo-controlled studies of nicotine replacement therapy (NRT). In laboratory studies, nicotine instructions decrease tobacco smoking, craving and/or withdrawal, while nicotine-specific effects have not been consistently reported. In field trials of NRT, there is a general failure to assess smokers' beliefs regarding their drug assignment. This omission makes it difficult to unequivocally attribute findings of placebo-controlled NRT studies to the physiological effects of nicotine. In sum, our review indicates that the placebo effects of nicotine, and specifically nicotine content expectations, may account for many of the benefits associated with nicotine delivery devices in both laboratory and field studies.
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Affiliation(s)
- Reuven Dar
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Sean P Barrett
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
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Levin ED, Hao I, Burke DA, Cauley M, Hall BJ, Rezvani AH. Effects of tobacco smoke constituents, anabasine and anatabine, on memory and attention in female rats. J Psychopharmacol 2014; 28:915-22. [PMID: 25122040 PMCID: PMC4305443 DOI: 10.1177/0269881114543721] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nicotine has been well characterized to improve memory and attention. Nicotine is the primary, but not only neuroactive compound in tobacco. Other tobacco constituents such as anabasine and anatabine also have agonist actions on nicotinic receptors. The current study investigated the effects of anabasine and anatabine on memory and attention. Adult female Sprague-Dawley rats were trained on a win-shift spatial working and reference memory task in the 16-arm radial maze or a visual signal detection operant task to test attention. Acute dose-effect functions of anabasine and anatabine over two orders of magnitude were evaluated for both tasks. In the radial-arm maze memory test, anabasine but not anatabine significantly reduced the memory impairment caused by the NMDA antagonist dizocilpine (MK-801). In the signal detection attentional task, anatabine but not anabasine significantly attenuated the attentional impairment caused by dizocilpine. These studies show that non-nicotine nicotinic agonists in tobacco, similar to nicotine, can significantly improve memory and attentional function. Both anabasine and anatabine produced cognitive improvement, but their effectiveness differed with regard to memory and attention. Follow-up studies with anabasine and anatabine are called for to determine their efficacy as therapeutics for memory and attentional dysfunction.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Ian Hao
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Dennis A Burke
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Marty Cauley
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Brandon J Hall
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
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