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Lin Y, Li H, Zheng S, Han R, Wu K, Tang S, Zhong X, Chen J. Elucidating tobacco smoke-induced craniofacial deformities: Biomarker and MAPK signaling dysregulation unraveled by cross-species multi-omics analysis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 288:117343. [PMID: 39549573 DOI: 10.1016/j.ecoenv.2024.117343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Revised: 10/27/2024] [Accepted: 11/10/2024] [Indexed: 11/18/2024]
Abstract
Tobacco smoke (TS), particularly secondhand and thirdhand smoke, poses a pervasive and intractable environmental hazard that promotes teratogenesis and the progression of craniofacial malformations, although the underlying mechanisms remain elusive. Using zebrafish larvae as a model, our research demonstrated a correlation between the increasing concentration of cigarette smoke extract (CSE) and the severity of craniofacial malformations, supported by Alcian blue staining and histological assessments. Through a combined mRNA-miRNA analysis and quantitative real-time PCR, we identified miR-96-5p, miR-152, miR-125b-2-3p, and miR-181a-3-3p as pivotal biomarkers in craniofacial cartilage development. Functional analyses revealed their association with the MAPK signaling pathway, oxidative stress (OS), and cell development, highlighting MAPK as a crucial mediator. Single-cell transcriptomics further disclosed aberrant MAPK activation in mesenchymal cells. Subsequent investigations in human embryonic palatal mesenchymal (HEPM) cells confirmed similar patterns of growth inhibition, apoptosis, and OS, and emphasized the cross-species consistency of these biomarkers and the over-activation of the MAPK signaling pathway. A comprehensive tri-omics analysis of HEPM cells identified pivotal genes, proteins, and metabolites within the MAPK pathway. This groundbreaking cross-species multi-omics study unveils novel biomarkers and MAPK pathway perturbations linked to TS-induced craniofacial developmental toxicity, promoting innovative clinical prediction, diagnosis, and interventional strategies to tackle TS-induced craniofacial malformations.
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Affiliation(s)
- Yuxin Lin
- Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, PR China.
| | - Hao Li
- Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, PR China.
| | - Shukai Zheng
- Shantou university medical college, Shantou, Guangdong 515041, PR China.
| | - Rui Han
- Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, PR China.
| | - Kusheng Wu
- Shantou university medical college, Shantou, Guangdong 515041, PR China.
| | - Shijie Tang
- Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, PR China.
| | - Xiaoping Zhong
- Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, PR China.
| | - Jiasheng Chen
- Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, PR China.
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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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3
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Yu J, Jing Z, Shen D, Yang M, Liu K, Xiang K, Zhou C, Gong X, Deng Y, Li Y, Yang S. Quercetin promotes autophagy to alleviate cigarette smoke-related periodontitis. J Periodontal Res 2023; 58:1082-1095. [PMID: 37533377 DOI: 10.1111/jre.13170] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/27/2023] [Accepted: 07/20/2023] [Indexed: 08/04/2023]
Abstract
BACKGROUND AND OBJECTIVES Cigarette smoking has been reported as an independent risk factor for periodontitis. Tobacco toxins affect periodontal tissue not only locally but also systemically, leading to the deterioration and recurrence of periodontitis. However, the mechanism of cigarette smoke-related periodontitis (CSRP) is unclear and thus lacks targeted treatment strategies. Quercetin, a plant-derived polyphenolic flavonoid, has been reported to have therapeutic effects on periodontitis due to its documented antioxidant activity. This study aimed to evaluate the effects of quercetin on CSRP and elucidated the underlying mechanism. METHODS The cigarette smoke-related ligature-induced periodontitis mouse model was established by intraperitoneal injection of cigarette smoke extract (CSE) and silk ligation of bilateral maxillary second molars. Quercetin was adopted by gavage as a therapeutic strategy. Micro-computed tomography was used to evaluate the alveolar bone resorption. Immunohistochemistry detected the oxidative stress and autophagy markers in vivo. Cell viability was determined by Cell Counting Kit-8, and oxidative stress levels were tested by 2,7-dichlorodihydrofluorescein diacetate probe and lipid peroxidation malondialdehyde assay kit. Alkaline phosphatase and alizarin red staining were used to determine osteogenic differentiation. Network pharmacology analysis, molecular docking, and western blot were utilized to elucidate the underlying molecular mechanism. RESULTS Alveolar bone resorption was exacerbated and oxidative stress products were accumulated during CSE exposure in vivo. Oxidative stress damage induced by CSE caused inhibition of osteogenic differentiation in vitro. Quercetin effectively protected the osteogenic differentiation of human periodontal ligament cells (hPDLCs) and periodontal tissue by upregulating the expression of Beclin-1 thus to promote autophagy and reduce oxidative stress damage. CONCLUSION Our results established a role of oxidative stress damage and autophagy dysfunction in the mechanism of CSE-induced destruction of periodontal tissue and hPDLCs, and provided a potential application value of quercetin to ameliorate CSRP.
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Affiliation(s)
- Jinrui Yu
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Zheng Jing
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Danfeng Shen
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Mingcong Yang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Kehao Liu
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Kai Xiang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Chongjing Zhou
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Xuerui Gong
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Yangjia Deng
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Yuzhou Li
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Sheng Yang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
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Reynaga DD, Cano M, Belluzzi JD, Leslie FM. Chronic exposure to cigarette smoke extract increases nicotine withdrawal symptoms in adult and adolescent male rats. ADVANCES IN DRUG AND ALCOHOL RESEARCH 2023; 3:11324. [PMID: 38389812 PMCID: PMC10880785 DOI: 10.3389/adar.2023.11324] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 08/29/2023] [Indexed: 02/24/2024]
Abstract
The aim of the current study was to determine whether non-nicotine constituents of cigarette smoke contribute to nicotine dependence in adolescent and adult male Sprague Dawley rats. For 10 days animals were given three times daily intravenous injections of nicotine (1.5 mg/kg/day) or cigarette smoke extract (CSE) containing an equivalent dose of nicotine. Both spontaneous and mecamylamine-precipitated withdrawal were then measured. Chronic treatment with CSE induced significantly greater somatic and affective withdrawal signs than nicotine in both adolescents and adults. Mecamylamine-precipitated somatic signs were similar at both ages. In contrast, animals spontaneously withdrawn from chronic drug treatment exhibited significant age differences: whereas adolescents chronically treated with nicotine did not show somatic signs, those treated with CSE showed similar physical withdrawal to those of adults. Mecamylamine did not precipitate anxiety-like behavior at either age. However, both adolescents and adults showed significant anxiety in a light-dark box test 18 h after spontaneous withdrawal. Anxiety-like behavior was still evident in an open field test 1 month after termination of drug treatment, with adolescents showing significantly greater affective symptoms than adults. Our findings indicate that non-nicotine constituents of cigarette smoke do contribute to dependence in both adolescents and adults and emphasize the importance of including smoke constituents with nicotine in animal models of tobacco dependence.
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Affiliation(s)
- Daisy D Reynaga
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, United States
| | - Michelle Cano
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, United States
| | - James D Belluzzi
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, United States
| | - Frances M Leslie
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, United States
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Dai Y, Jiang W, Zheng Y, He P, Zhu R, Fei J, Xu W, Liu C, Hong J. Recyclable molecularly imprinted polymers based on Fe3O4@SiO2 and PAMAM dendrimers for the determination of myosmine in cigarettes. Mikrochim Acta 2022; 189:467. [DOI: 10.1007/s00604-022-05529-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 10/04/2022] [Indexed: 11/25/2022]
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6
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Liu G, Wang R, Chen H, Wu P, Fu Y, Li K, Liu M, Shi Z, Zhang Y, Su Y, Song L, Hou H, Hu Q. Non-nicotine constituents in cigarette smoke extract enhance nicotine addiction through monoamine oxidase A inhibition. Front Neurosci 2022; 16:1058254. [PMID: 36507317 PMCID: PMC9729261 DOI: 10.3389/fnins.2022.1058254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/07/2022] [Indexed: 11/26/2022] Open
Abstract
Tobacco addiction has been largely attributed to nicotine, a component in tobacco leaves and smoke. However, extensive evidence suggests that some non-nicotine components of smoke should not be overlooked when considering tobacco dependence. Yet, their individual effect and synergistic effect on nicotine reinforcement remain poorly understood. The study herein focused on the role of non-nicotine constituents in promoting the effects of nicotine and their independent reinforcing effects. Denicotinized cigarettes were prepared by chemical extracting of cut tobacco, and the cigarette smoke extracts (CSE, used as a proxy for non-nicotine ingredients) were obtained by machine-smoking the cigarettes and DMSO extraction. The compositions of harmful components, nicotine, and other minor alkaloids in both cut tobacco and the CSE of experimental denicotinized cigarettes were examined by GC-MS, and compared with 3R4F reference cigarettes. individually and in synergy with nicotine were determined by conditioned place preference (CPP), dopamine (DA) level detection, the open field test (OFT), and the elevated plus maze (EPM). Finally, the potential enhancement mechanism of non-nicotinic constituents was investigated by nicotine metabolism and monoamine oxidase A (MAOA) activity inhibition in the striatum of mice and human recombinant MAOA. Thenicotine content in smoke from the experimental denicotinized cigarettes (under ISO machine-smoking conditions) was reduced by 95.1% and retained most minor alkaloids, relative to the 3R4F reference cigarettes. It was found that non-nicotine constituents increased acute locomotor activities. This was especially pronounced for DA levels in NAc and CPP scores, decreased the time in center zone. There were no differences in these metrics with DNC group when compared to the NS group. Non-nicotine constituents alone did not show reinforcing effects in CPP or striatum DA levels in mice. However, in the presence of nicotine, non-nicotine constituents further increased the reinforcing effects. Furthermore, non-nicotine constituents may enhance nicotine's reinforcing effects by inhibiting striatum MAOA activity rather than affecting nicotine metabolism or total striatum DA content in mice. These findings expand our knowledge of the effect on smoking reinforcement of non-nicotine constituents found in tobacco products.
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Affiliation(s)
- Guanglin Liu
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China
| | - Ruiyan Wang
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China
| | - Huan Chen
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China
| | - Ping Wu
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Beijing, China
| | - Yaning Fu
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China
| | - Kaixin Li
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China
| | - Mingda Liu
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China
| | - Zhihao Shi
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Yuan Zhang
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Yue Su
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Lingxiao Song
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Hongwei Hou
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China,*Correspondence: Hongwei Hou,
| | - Qingyuan Hu
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, China,Key Laboratory of Tobacco Biological Effects, Zhengzhou, China,Joint Laboratory of Translational Neurobiology, Zhengzhou, China,Qingyuan Hu,
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Harris AC, Muelken P, Alcheva A, Stepanov I, LeSage MG. Cigarette Smoke Extract, but Not Electronic Cigarette Aerosol Extract, Inhibits Monoamine Oxidase in vitro and Produces Greater Acute Aversive/Anhedonic Effects Than Nicotine Alone on Intracranial Self-Stimulation in Rats. Front Neurosci 2022; 16:868088. [PMID: 35712461 PMCID: PMC9196039 DOI: 10.3389/fnins.2022.868088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/25/2022] [Indexed: 12/14/2022] Open
Abstract
Conventional tobacco cigarettes appear to have greater abuse liability than non-combusted products such as electronic cigarettes (ECs) and nicotine replacement therapy (NRT). This may be due to the higher levels of behaviorally active non-nicotine constituents [e.g., monoamine oxidase (MAO) inhibitors such as β-carbolines] in cigarette smoke (CS) compared to non-combusted products. To evaluate this hypothesis, the current studies compared the relative abuse liability of CS and EC aerosol extracts containing nicotine and a range of non-nicotine constituents to that of nicotine alone (NRT analog) using intracranial self-stimulation (ICSS) in rats. Effects of formulations on brain MAO activity in vitro and ex vivo were also studied to evaluate the potential role of MAO inhibition in the ICSS study. CS extract contained higher levels of several behaviorally active non-nicotine constituents (e.g., the β-carbolines norharmane and harmane) than EC extract. Nicotine alone reduced ICSS thresholds at a moderate nicotine dose, suggesting a reinforcement-enhancing effect that may promote abuse liability, and elevated ICSS thresholds at a high nicotine dose, suggesting an aversive/anhedonic effect that may limit abuse liability. CS extract elevated ICSS thresholds to a greater degree than nicotine alone at high nicotine doses. Effects of EC extract on ICSS did not differ from those of nicotine alone. Finally, CS extract significantly inhibited MAO-A and MAO-B activity in vitro, whereas EC extract and nicotine alone did not. None of the formulations inhibited MAO measured ex vivo. These findings indicate greater acute aversive/anhedonic effects for CS extract compared to nicotine alone, suggesting lower abuse liability. Although confirmation of our findings using other dosing regimens, preclinical addiction models, and tobacco product extracts is needed, these findings suggest that the centrally-mediated effects of MAO inhibitors and other non-nicotine constituents may not account for the greater abuse liability of cigarettes compared to non-combusted products. Nonetheless, identifying the specific constituent(s) mediating the effects of CS extracts in this study could help clarify mechanisms mediating tobacco addiction and inform FDA product standards.
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Affiliation(s)
- Andrew C. Harris
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States,Department of Medicine, University of Minnesota, Minneapolis, MN, United States,Department of Psychology, University of Minnesota, Minneapolis, MN, United States,*Correspondence: Andrew C. Harris,
| | - Peter Muelken
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States
| | - Aleksandra Alcheva
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
| | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
| | - Mark G. LeSage
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States,Department of Medicine, University of Minnesota, Minneapolis, MN, United States,Department of Psychology, University of Minnesota, Minneapolis, MN, United States
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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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Rehder Silinski MA, Uenoyama T, Coleman DP, Blake JC, Thomas BF, Marusich JA, Jackson KJ, Meredith SE, Gahl RF. Analysis of Nicotine and Non-nicotine Tobacco Constituents in Aqueous Smoke/Aerosol Extracts by UHPLC and Ultraperformance Convergence Chromatography-Tandem Mass Spectrometry. Chem Res Toxicol 2020; 33:2988-3000. [PMID: 33226218 DOI: 10.1021/acs.chemrestox.0c00312] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The non-nicotine constituents of tobacco may alter the reinforcing effects of nicotine, but the quantitative and qualitative profiles of these chemicals in tobacco products such as electronic cigarettes (e-cigarettes), cigars, and waterpipe tobacco are not well characterized. The objective of this work was to develop and validate analytical methods to utilize saline both as an extraction solvent for smoke condensates from cigarettes, little cigars, and waterpipe tobacco and aerosols from e-cigarettes and as a delivery vehicle of nicotine and non-nicotine constitents for nonclinical pharmacological studies. Ultrahigh-performance liquid chromatography was used to analyze nicotine and acetaldehyde, and a novel ultraperformance convergence chromatography-tandem mass spectrometry method was developed to analyze anabasine, anatabine, cotinine, myosmine, nornicotine, harmane, and norharmane. Linearity was confirmed for each standard curve with correlation coefficients (r) ≥ 0.99, and relative errors (RE) for the standards were ≤±10% over the calibration ranges. Method validation was performed by preparing triplicate samples in saline to mimic the composition and concentration of each analyte in the smoke or aerosol condensate and were used to determine method accuracy and precision. Relative standard deviation values were ≤15% and mean RE ≤15% for each analyte at each concentration level. Selectivity of the methods was demonstrated by the absence of peaks in blank vehicle or diluent samples. Storage stability was assessed over ∼45 days. Precision (%RSD ≤ 13) and recovery (percent of day 0 ≥ 80%) indicated that the saline formulations of all four products could be considered stable for up to ∼45 days at 4-8 °C. Therefore, the use of saline both as an extraction solvent and as a delivery vehicle adds versatility and improved performance in the study of the pharmacological effects of constituents from mainstream smoke and aerosols generated from cigarettes, little cigars, waterpipes, and e-cigarettes.
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Affiliation(s)
| | - Teruyo Uenoyama
- RTI International, P. O. Box 12194, Research Triangle Park, North Carolina 27709, United States
| | - Donna P Coleman
- RTI International, P. O. Box 12194, Research Triangle Park, North Carolina 27709, United States
| | - James C Blake
- RTI International, P. O. Box 12194, Research Triangle Park, North Carolina 27709, United States
| | - Brian F Thomas
- RTI International, P. O. Box 12194, Research Triangle Park, North Carolina 27709, United States
| | - Julie A Marusich
- RTI International, P. O. Box 12194, Research Triangle Park, North Carolina 27709, United States
| | - Kia J Jackson
- U. S. Food and Drug Administration, Center for Tobacco Products, Silver Spring, Maryland 20993, United States
| | - Steven E Meredith
- U. S. Food and Drug Administration, Center for Tobacco Products, Silver Spring, Maryland 20993, United States
| | - Robert F Gahl
- U. S. Food and Drug Administration, Center for Tobacco Products, Silver Spring, Maryland 20993, United States
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10
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Cano M, Reynaga DD, Belluzzi JD, Loughlin SE, Leslie F. Chronic exposure to cigarette smoke extract upregulates nicotinic receptor binding in adult and adolescent rats. Neuropharmacology 2020; 181:108308. [PMID: 32950561 PMCID: PMC7655523 DOI: 10.1016/j.neuropharm.2020.108308] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/11/2020] [Accepted: 09/13/2020] [Indexed: 01/23/2023]
Abstract
Heavy smokers display increased radioligand binding of nicotinic acetylcholine receptors (nAChRs). This "upregulation" is thought to be a contributing factor to tobacco dependence. Although cigarette smoke contains thousands of constituents that can contribute to nicotine dependence, it is not well understood whether non-nicotine constituents contribute to nAChR upregulation. In this study, we used an aqueous cigarette smoke extract (CSE), which contains nicotine and soluble constituents of cigarette smoke, to induce nAChR upregulation in adult and adolescent rats. To do this, male rats were exposed to nicotine or CSE (1.5 mg/kg/day nicotine equivalent, intravenously) daily for ten days. This experimental procedure produces equivalent levels of brain and plasma nicotine in nicotine- and CSE-treated animals. We then assessed nAChR upregulation using quantitative autoradiography to measure changes in three nAChR types. Adolescents were found to have consistently greater α4β2 nAChR binding than adults in many brain regions. Chronic nicotine exposure did not significantly increase nAChR binding in any brain region at either age. Chronic CSE exposure selectively increased α4β2 nAChR binding in adolescent medial amygdala and α7 binding in adolescent central amygdala and lateral hypothalamus. CSE also increased α3β4 nAChR binding in the medial habenula and interpeduncular nucleus, and α7 binding in the medial amygdala, independent of age. Overall, this work provides evidence that cigarette smoke constituents influence nAChR upregulation in an age-, nAChR type- and region-dependent manner.
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Affiliation(s)
- Michelle Cano
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA.
| | - Daisy D Reynaga
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - James D Belluzzi
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Sandra E Loughlin
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Frances Leslie
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
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11
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Harris AC, Muelken P, LeSage MG. β-Carbolines found in cigarette smoke elevate intracranial self-stimulation thresholds in rats. Pharmacol Biochem Behav 2020; 198:173041. [PMID: 32926882 PMCID: PMC7554228 DOI: 10.1016/j.pbb.2020.173041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/25/2022]
Abstract
Identifying novel constituents that contribute to tobacco addiction is essential for developing more effective treatments and informing FDA regulation of tobacco products. While preclinical data indicate that monoamine oxidase (MAO) inhibitors can have abuse liability or potentiate the addiction-related effects of nicotine, most of these studies have used clinical MAO inhibitors (e.g., tranylcypromine) that are not present in cigarette smoke. The primary goal of this study was to evaluate the abuse potential of the β-carbolines harmane, norharmane, and harmine - MAO inhibitors that are found in cigarette smoke - in an intracranial self-simulation (ICSS) model in rats. A secondary goal was to evaluate the ability of norharmane to influence nicotine's acute effects on ICSS. None of the β-carbolines lowered ICSS thresholds at any dose studied when administered alone, suggesting a lack of abuse liability. Rather, all three β-carbolines produced dose-dependent elevations in ICSS thresholds, indicating aversive/anhedonic effects. Harmane and harmine also elevated ICSS response latencies, suggesting a disruption of motor function, albeit with reduced potency compared to their ICSS threshold-elevating effects. Norharmane (2.5 mg/kg) modestly attenuated the effects of nicotine on ICSS thresholds. Our findings indicate that these β-carbolines produced only aversive/anhedonic effects in an ICSS model when administered alone, and that norharmane unexpectedly attenuated nicotines acute effects on ICSS. Future work evaluating the addiction-related effects of nicotine combined with these and other MAO inhibitors present in smoke may be useful for understanding the role of MAO inhibition in tobacco addiction and informing FDA tobacco regulation.
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Affiliation(s)
- Andrew C Harris
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States of America; Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, United States of America; Department of Psychology, University of Minnesota, Minneapolis, MN, United States of America.
| | - Peter Muelken
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States of America
| | - Mark G LeSage
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States of America; Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, United States of America; Department of Psychology, University of Minnesota, Minneapolis, MN, United States of America
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12
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Cross SJ, Reynaga DD, Cano M, Belluzzi JD, Zaveri NT, Leslie FM. Differences in mechanisms underlying reinstatement of cigarette smoke extract- and nicotine-seeking behavior in rats. Neuropharmacology 2020; 162:107846. [PMID: 31704271 PMCID: PMC7034132 DOI: 10.1016/j.neuropharm.2019.107846] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 10/18/2019] [Accepted: 11/05/2019] [Indexed: 12/28/2022]
Abstract
Despite extensive research, current therapies for smoking cessation are largely ineffective at maintaining abstinence for more than a year. Whereas most preclinical studies use nicotine alone, the goal of the present study was to evaluate whether inclusion of non-nicotine tobacco constituents provides better face validity for the development of new pharmacological therapies for smoking cessation. Here, we trained adult male rats to self-administer nicotine alone or cigarette smoke extract (CSE), which contains nicotine and other aqueous constituents of cigarette smoke. After stable self-administration behavior was established, animals underwent extinction training followed by drug and cue primed reinstatement testing. We show that animals that self-administered CSE had significant reinstatement in all drug and drug + cue stimulus conditions whereas animals that self-administered nicotine only showed significant reinstatement in the drug + cue conditions. AT-1001, an α3β4 nicotinic acetylcholine receptor (nAChR) functional antagonist, attenuated drug + cue-primed reinstatement of both CSE- and nicotine-seeking behavior. However, AT-1001 was less potent in blocking drug-primed reinstatement in animals that had self-administered CSE than in those that had self-administered nicotine alone. This was the case even when nicotine was used to prime reinstatement in animals that had self-administered CSE, suggesting that prior CSE exposure had altered the functional role of α3β4-containing nAChRs in drug-seeking behavior. These findings confirm the importance of non-nicotine tobacco constituents and α3β4* nAChRs in cue- and nicotine-primed craving. They also suggest that tests using CSE may be more valid models to study tobacco dependence than use of nicotine alone.
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Affiliation(s)
- Sarah J Cross
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA.
| | - Daisy D Reynaga
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Michelle Cano
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - James D Belluzzi
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | | | - Frances M Leslie
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA; Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
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13
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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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14
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Fowler CD, Gipson CD, Kleykamp BA, Rupprecht LE, Harrell PT, Rees VW, Gould TJ, Oliver J, Bagdas D, Damaj MI, Schmidt HD, Duncan A, De Biasi M. Basic Science and Public Policy: Informed Regulation for Nicotine and Tobacco Products. Nicotine Tob Res 2019; 20:789-799. [PMID: 29065200 DOI: 10.1093/ntr/ntx175] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 08/01/2017] [Indexed: 12/25/2022]
Abstract
Introduction Scientific discoveries over the past few decades have provided significant insight into the abuse liability and negative health consequences associated with tobacco and nicotine-containing products. While many of these advances have led to the development of policies and laws that regulate access to and formulations of these products, further research is critical to guide future regulatory efforts, especially as novel nicotine-containing products are introduced and selectively marketed to vulnerable populations. Discussion In this narrative review, we provide an overview of the scientific findings that have impacted regulatory policy and discuss considerations for further translation of science into policy decisions. We propose that open, bidirectional communication between scientists and policy makers is essential to develop transformative preventive- and intervention-focused policies and programs to reduce appeal, abuse liability, and toxicity of the products. Conclusions Through these types of interactions, collaborative efforts to inform and modify policy have the potential to significantly decrease the use of tobacco and alternative nicotine products and thus enhance health outcomes for individuals. Implications This work addresses current topics in the nicotine and tobacco research field to emphasize the importance of basic science research and provide examples of how it can be utilized to inform public policy. In addition to relaying current thoughts on the topic from experts in the field, the article encourages continued efforts and communication between basic scientists and policy officials.
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Affiliation(s)
- Christie D Fowler
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA
| | | | | | - Laura E Rupprecht
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA
| | - Paul T Harrell
- Division of Community Health & Research, Department of Pediatrics, Eastern Virginia Medical School, Norfolk, VA
| | - Vaughan W Rees
- Center for Global Tobacco Control, Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, Boston, MA
| | - Thomas J Gould
- Department of Biobehavioral Health, Pennsylvania State University, University Park, PA
| | - Jason Oliver
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC
| | - Deniz Bagdas
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA
| | - Heath D Schmidt
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, PA
| | - Alexander Duncan
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mariella De Biasi
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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15
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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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16
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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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17
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Smethells JR, Harris AC, Burroughs D, Hursh SR, LeSage MG. Substitutability of nicotine alone and an electronic cigarette liquid using a concurrent choice assay in rats: A behavioral economic analysis. Drug Alcohol Depend 2018; 185:58-66. [PMID: 29427916 PMCID: PMC5889753 DOI: 10.1016/j.drugalcdep.2017.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/06/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND For the Food and Drug Administration to effectively regulate tobacco products, the contribution of non-nicotine tobacco constituents to the abuse liability of tobacco must be well understood. Our previous work compared the abuse liability of electronic cigarette refill liquids (EC liquids) and nicotine (Nic) alone when each was available in isolation and found no difference in abuse liability (i.e., demand elasticity). Another, and potentially more sensitive measure, would be to examine abuse liability in a choice context, which also provides a better model of the tobacco marketplace. METHODS Demand elasticity for Nic alone and an EC liquid were measured when only one formulation was available (alone-price demand) and when both formulations were concurrently available (own-price demand), allowing an assessment of the degree to which each formulation served as a substitute (cross-price demand) when available at a low fixed-price. RESULTS Own-price demand for both formulations were more elastic compared to alone-price demand, indicating that availability of a substitute increased demand elasticity. During concurrent access, consumption of the fixed-price formulation increased as the unit-price of the other formulation increased. The rate of increase was similar between formulations, indicating that they served as symmetrical substitutes. CONCLUSION The cross-price model reliably quantified the substitutability of both nicotine formulations and indicated that the direct CNS effects of non-nicotine constituents in EC liquid did not alter its abuse liability compared to Nic. These data highlight the sensitivity of this model and its potential utility for examining the relative abuse liability and substitutability of tobacco products.
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Affiliation(s)
- John R Smethells
- Minneapolis Medical Research Foundation, 914 S. 8th Street, Minneapolis, MN, United States.
| | - Andrew C Harris
- Minneapolis Medical Research Foundation, 914 S. 8th Street, Minneapolis, MN, United States; Department of Medicine, University of Minnesota Medical School, 420 Delaware Street, SE, Minneapolis, MN, United States; Department of Psychology, University of Minnesota, 75 E. River Road, Minneapolis, MN, United States
| | - Danielle Burroughs
- Minneapolis Medical Research Foundation, 914 S. 8th Street, Minneapolis, MN, United States
| | - Steven R Hursh
- Institutes for Behavior Resources, Inc., 2104 Maryland Avenue, Baltimore, MD, United States; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD, United States
| | - Mark G LeSage
- Minneapolis Medical Research Foundation, 914 S. 8th Street, Minneapolis, MN, United States; Department of Medicine, University of Minnesota Medical School, 420 Delaware Street, SE, Minneapolis, MN, United States; Department of Psychology, University of Minnesota, 75 E. River Road, Minneapolis, MN, United States
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18
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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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19
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Harris AC, Muelken P, Smethells JR, Krueger M, LeSage MG. Similar precipitated withdrawal effects on intracranial self-stimulation during chronic infusion of an e-cigarette liquid or nicotine alone. Pharmacol Biochem Behav 2017; 161:1-5. [PMID: 28867606 DOI: 10.1016/j.pbb.2017.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/28/2017] [Accepted: 08/30/2017] [Indexed: 11/19/2022]
Abstract
The FDA recently extended their regulatory authority to electronic cigarettes (ECs). Because the abuse liability of ECs is a leading concern of the FDA, animal models are urgently needed to identify factors that influence the relative abuse liability of these products. The ability of tobacco products to induce nicotine dependence, defined by the emergence of anhedonia and other symptoms of nicotine withdrawal following cessation of their use, contributes to tobacco abuse liability. The present study compared the severity of precipitated withdrawal during chronic infusion of nicotine alone or nicotine-dose equivalent concentrations of three different EC refill liquids in rats, as indicated by elevations in intracranial self-stimulation (ICSS) thresholds (anhedonia-like behavior). Because these EC liquids contain constituents that may enhance their abuse liability (e.g., minor alkaloids), we hypothesized that they would be associated with greater withdrawal effects than nicotine alone. Results indicated that the nicotinic acetylcholine receptor antagonist mecamylamine precipitated elevations in ICSS thresholds in rats receiving a chronic infusion of nicotine alone or EC liquids (3.2mg/kg/day, via osmotic pump). Magnitude of this effect did not differ between formulations. Our findings indicate that nicotine alone is the primary CNS determinant of the ability of ECs to engender dependence. Combined with our previous findings that nicotine alone and these EC liquids do not differ in other preclinical addiction models, these data suggest that product standards set by the FDA to reduce EC abuse liability should primarily target nicotine, other constituents with peripheral sensory effects (e.g. flavorants), and factors that influence product appeal (e.g., marketing).
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Affiliation(s)
- A 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.
| | - P Muelken
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN, USA
| | - J R Smethells
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA
| | - M Krueger
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - M 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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20
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LeSage MG, Staley M, Muelken P, Smethells JR, Stepanov I, Vogel RI, Pentel PR, Harris AC. Abuse liability assessment of an e-cigarette refill liquid using intracranial self-stimulation and self-administration models in rats. Drug Alcohol Depend 2016; 168:76-88. [PMID: 27627814 PMCID: PMC5257285 DOI: 10.1016/j.drugalcdep.2016.08.628] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/14/2016] [Accepted: 08/22/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND The popularity of electronic cigarettes (ECs) has increased dramatically despite their unknown health consequences. Because the abuse liability of ECs is one of the leading concerns of the Food and Drug Administration (FDA), models to assess it are urgently needed to inform FDA regulatory decisions regarding these products. The purpose of this study was to assess the relative abuse liability of an EC liquid compared to nicotine alone in rats. Because this EC liquid contains non-nicotine constituents that may enhance its abuse liability, we hypothesized that it would have greater abuse liability than nicotine alone. METHODS Nicotine alone and nicotine dose-equivalent concentrations of EC liquid were compared in terms of their acute effects on intracranial self-stimulation (ICSS) thresholds, acquisition of self-administration, reinforcing efficacy (i.e., elasticity of demand), blockade of these behavioral effects by mecamylamine, nicotine pharmacokinetics and nicotinic acetylcholine receptor binding and activation. RESULTS There were no significant differences between formulations on any measure, except that EC liquid produced less of an elevation in ICSS thresholds at high nicotine doses. CONCLUSIONS Collectively, these findings suggest that the relative abuse liability of this EC liquid is similar to that of nicotine alone in terms of its reinforcing and reinforcement-enhancing effects, but that it may have less aversive/anhedonic effects at high doses. The present methods may be useful for assessing the abuse liability of other ECs to inform potential FDA regulation of those products.
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Affiliation(s)
- MG LeSage
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota, Minneapolis, MN,Department of Psychology, University of Minnesota, Minneapolis, MN, 55455
| | - M Staley
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN
| | - P Muelken
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN
| | - JR Smethells
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Psychiatry, University of Minnesota, Minneapolis, MN, 55455
| | - I Stepanov
- Masonic Cancer, Center University of Minnesota, Minneapolis, MN
| | - RI Vogel
- Masonic Cancer Center Biostatistics and Bioinformatics Core ,University of Minnesota Minneapolis, MN
| | - PR Pentel
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota, Minneapolis, MN
| | - AC Harris
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota, Minneapolis, MN,Department of Psychology, University of Minnesota, Minneapolis, MN, 55455
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21
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Gellner CA, Belluzzi JD, Leslie FM. Self-administration of nicotine and cigarette smoke extract in adolescent and adult rats. Neuropharmacology 2016; 109:247-253. [PMID: 27346207 PMCID: PMC4970954 DOI: 10.1016/j.neuropharm.2016.06.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 11/17/2022]
Abstract
Although smoking initiation typically occurs during adolescence, most preclinical studies of tobacco use involve adult animals. Furthermore, their focus is largely on nicotine alone, even though cigarette smoke contains thousands of constituents. The present study therefore aimed to determine whether aqueous constituents in cigarette smoke affect acquisition of nicotine self-administration during adolescence in rats. Adolescent and adult male rats, aged postnatal day (P) 25 and 85, respectively, were food trained on a fixed ratio 1 (FR1) schedule, then allowed to self-administer one of 5 doses of nicotine (0, 3.75, 7.5, 15, or 30 μg/kg) or aqueous cigarette smoke extract (CSE) with equivalent nicotine content. Three progressively more difficult schedules of reinforcement, FR1, FR2, and FR5, were used. Both adolescent and adult rats acquired self-administration of nicotine and CSE. Nicotine and CSE similarly increased non-reinforced responding in adolescents, leading to enhanced overall drug intake as compared to adults. When data were corrected for age-dependent alterations in non-reinforced responding, adolescents responded more for low doses of nicotine and CSE than adults at the FR1 reinforcement schedule. No differences in adolescent responding for the two drugs were seen at this schedule, whereas adults had fewer responses for CSE than for nicotine. However, when the reinforcement schedule was increased to FR5, animals dose-dependently self-administered both nicotine and CSE, but no drug or age differences were observed. These data suggest that non-nicotine tobacco smoke constituents do not influence the reinforcing effect of nicotine in adolescents.
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Affiliation(s)
- Candice A Gellner
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA, USA.
| | - James D Belluzzi
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA, USA
| | - Frances M Leslie
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA, USA; Department of Anatomy & Neurobiology, School of Medicine, University of California, Irvine, CA, USA
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22
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Abstract
OBJECTIVE Preclinical abuse liability assessment is an essential component of tobacco regulatory science. The goal of this project was to evaluate the relative abuse liability of smokeless tobacco products in rats using aqueous extracts of those products. These extracts provide exposure to an extensive range of nicotine and non-nicotine tobacco constituents as occurs in humans. METHODS Rats were trained to self-administer either nicotine alone or extracts of Camel Snus or Kodiak smokeless tobacco at an equivalent nicotine unit dose. In Experiment 1, the relative reinforcing efficacy of these formulations was assessed in adults and adolescents using a progressive ratio schedule under limited-access conditions. In Experiment 2, relative reinforcing efficacy was assessed in adolescents under unlimited-access conditions using behavioral economic demand curve analysis. RESULTS The reinforcing efficacy of nicotine formulations was higher in adolescents than adults, but no difference was observed between formulations in either age group. Similarly, there was no difference in elasticity of demand between formulations in adolescents. CONCLUSIONS The present findings suggest that the abuse liability of these smokeless tobacco products is similar to nicotine alone, and that nicotine dose is the primary determinant of the reinforcing efficacy of systemic exposure to these products.
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Csabai D, Csekő K, Szaiff L, Varga Z, Miseta A, Helyes Z, Czéh B. Low intensity, long term exposure to tobacco smoke inhibits hippocampal neurogenesis in adult mice. Behav Brain Res 2016; 302:44-52. [PMID: 26792108 DOI: 10.1016/j.bbr.2016.01.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 10/22/2022]
Abstract
Previous data have shown that high dose of nicotine administration or tobacco smoke exposure can reduce cell formation and the survival rate of adult-born neurons in the dentate gyrus. Here, we subjected adult mice to low intensity cigarette smoke exposure over long time periods. We did a 2×30min/day smoke exposure with two cigarettes per occasion over 1- or 2-months. Subsequently, we carried out a systematic quantitative histopathological analysis to assess the number of newborn neurons in the dentate gyrus. To investigate cell proliferation, the exogenous marker 5-bromo-2'-deoxyuridine (BrdU) was administered on the last experimental day and animals were sacrificed 2h later. To investigate the effect of tobacco smoke on the population of immature neurons, we quantified the number of doublecortin-positive (DCX+) neurons in the same animals. We found that exposing animals to cigarette smoke for 1- or 2-months had no influence on cell proliferation rate, but significantly reduced the number of DCX-positive immature neurons. Our tobacco smoke exposure regimen caused no substantial changes in respiratory functions, but histopathological analysis of the pulmonary tissue revealed a marked perivascular/peribronchial edema formation after 1-month and signs of chronic pulmonary inflammation after 2-months of cigarette smoke exposure. These data demonstrate that even mild exposure to cigarette smoke, without significantly affecting respiratory functions, can have a negative effect on adult-born neurons in the dentate gyrus, when applied over longer time periods. Our data indicate that besides nicotine other factors, such as inflammatory mediators, may also contribute to this effect.
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Affiliation(s)
- Dávid Csabai
- MTA-PTE, Neurobiology of Stress Research Group, Szentágothai Research Center, University of Pécs, 7624 Pécs, Hungary
| | - Kata Csekő
- Department of Pharmacology and Pharmacotherapy, University of Pécs, Medical School, 7624 Pécs, Hungary
| | - Lilla Szaiff
- MTA-PTE, Neurobiology of Stress Research Group, Szentágothai Research Center, University of Pécs, 7624 Pécs, Hungary
| | - Zsófia Varga
- MTA-PTE, Neurobiology of Stress Research Group, Szentágothai Research Center, University of Pécs, 7624 Pécs, Hungary
| | - Attila Miseta
- Department of Laboratory Medicine, University of Pécs, Medical School, 7624 Pécs, Hungary
| | - Zsuzsanna Helyes
- Department of Pharmacology and Pharmacotherapy, University of Pécs, Medical School, 7624 Pécs, Hungary; MTA-PTE, Chronic Pain Research Group, Szentágothai Research Center, University of Pécs, 7624 Pécs, Hungary; PharmInVivo Ltd, 7629 Pécs, Hungary
| | - Boldizsár Czéh
- MTA-PTE, Neurobiology of Stress Research Group, Szentágothai Research Center, University of Pécs, 7624 Pécs, Hungary; Department of Laboratory Medicine, University of Pécs, Medical School, 7624 Pécs, Hungary.
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Ponzoni L, Moretti M, Sala M, Fasoli F, Mucchietto V, Lucini V, Cannazza G, Gallesi G, Castellana CN, Clementi F, Zoli M, Gotti C, Braida D. Different physiological and behavioural effects of e-cigarette vapour and cigarette smoke in mice. Eur Neuropsychopharmacol 2015; 25:1775-86. [PMID: 26141510 DOI: 10.1016/j.euroneuro.2015.06.010] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/25/2015] [Accepted: 06/12/2015] [Indexed: 01/12/2023]
Abstract
Nicotine is the primary addictive substance in tobacco smoke and electronic cigarette (e-cig) vapour. Methodological limitations have made it difficult to compare the role of the nicotine and non-nicotine constituents of tobacco smoke. The aim of this study was to compare the effects of traditional cigarette smoke and e-cig vapour containing the same amount of nicotine in male BALB/c mice exposed to the smoke of 21 cigarettes or e-cig vapour containing 16.8 mg of nicotine delivered by means of a mechanical ventilator for three 30-min sessions/day for seven weeks. One hour after the last session, half of the animals were sacrificed for neurochemical analysis, and the others underwent mecamylamine-precipitated or spontaneous withdrawal for the purposes of behavioural analysis. Chronic intermittent non-contingent, second-hand exposure to cigarette smoke or e-cig vapour led to similar brain cotinine and nicotine levels, similar urine cotinine levels and the similar up-regulation of α4β2 nicotinic acetylcholine receptors in different brain areas, but had different effects on body weight, food intake, and the signs of mecamylamine-precipitated and spontaneous withdrawal episodic memory and emotional responses. The findings of this study demonstrate for the first time that e-cig vapour induces addiction-related neurochemical, physiological and behavioural alterations. The fact that inhaled cigarette smoke and e-cig vapour have partially different dependence-related effects indicates that compounds other than nicotine contribute to tobacco dependence.
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Affiliation(s)
- L Ponzoni
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
| | - M Moretti
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto di Neuroscienze, Milan, Italy
| | - M Sala
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto di Neuroscienze, Milan, Italy
| | - F Fasoli
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto di Neuroscienze, Milan, Italy
| | - V Mucchietto
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto di Neuroscienze, Milan, Italy
| | - V Lucini
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
| | - G Cannazza
- Dipartimenti di Scienze della Vita, Università di Modena e Reggio Emilia, Modena, Italy
| | - G Gallesi
- Scienze Biomediche, Metaboliche e Neuroscienze, Università di Modena e Reggio Emilia, Modena, Italy
| | - C N Castellana
- Dipartimento di Medicina di Laboratorio e Anatomia Patologica, A.O.U. Policlinico, Modena, Italy
| | - F Clementi
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto di Neuroscienze, Milan, Italy
| | - M Zoli
- Medicina Diagnostica, Clinica e Sanità Pubblica, Università di Modena e Reggio Emilia, Modena, Italy
| | - C Gotti
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto di Neuroscienze, Milan, Italy.
| | - D Braida
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
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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: 44] [Impact Index Per Article: 4.9] [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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26
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Harris AC, Tally L, Schmidt CE, Muelken P, Stepanov I, Saha S, Vogel RI, LeSage MG. Animal models to assess the abuse liability of tobacco products: effects of smokeless tobacco extracts on intracranial self-stimulation. Drug Alcohol Depend 2015; 147:60-7. [PMID: 25561387 PMCID: PMC4337227 DOI: 10.1016/j.drugalcdep.2014.12.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/12/2014] [Accepted: 12/11/2014] [Indexed: 01/11/2023]
Abstract
BACKGROUND Preclinical models are needed to inform regulation of tobacco products by the Food and Drug Administration (FDA). Typically, animal models of tobacco addiction involve exposure to nicotine alone or nicotine combined with isolated tobacco constituents (e.g. minor alkaloids). The goal of this study was to develop a model using extracts derived from tobacco products that contain a range of tobacco constituents to more closely model product exposure in humans. METHODS This study compared the addiction-related effects of nicotine alone and nicotine dose-equivalent concentrations of aqueous smokeless tobacco extracts on intracranial self-stimulation (ICSS) in rats. Extracts were prepared from Kodiak Wintergreen, a conventional product, or Camel Snus, a potential "modified risk tobacco product". Binding affinities of nicotine alone and extracts at various nicotinic acetylcholine receptor (nAChR) subtypes were also compared. RESULTS Kodiak and Camel Snus extracts contained levels of minor alkaloids within the range of those shown to enhance nicotine's behavioral effects when studied in isolation. Nonetheless, acute injection of both extracts produced reinforcement-enhancing (ICSS threshold-decreasing) effects similar to those of nicotine alone at low to moderate nicotine doses, as well as similar reinforcement-attenuating/aversive (ICSS threshold-increasing) effects at high nicotine doses. Extracts and nicotine alone also had similar binding affinity at all nAChRs studied. CONCLUSIONS Relative nicotine content is the primary pharmacological determinant of the abuse liability of Kodiak and Camel Snus as measured using ICSS. These models may be useful to compare the relative abuse liability of other tobacco products and to model FDA-mandated changes in product performance standards.
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Affiliation(s)
- Andrew C Harris
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA; Department of Psychology, University of Minnesota, Minneapolis, MN, USA.
| | - Laura Tally
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA
| | - Clare E Schmidt
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Peter Muelken
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN, USA
| | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Subhrakanti Saha
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Rachel Isaksson Vogel
- Masonic Cancer Center, Biostatistics and Bioinformatics Core, University of Minnesota Minneapolis, MN, USA
| | - Mark G LeSage
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA; Department of Psychology, University of Minnesota, Minneapolis, MN, USA
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