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Cooper SY, Olszewski NA, Tetteh-Quarshie S, Hill SP, Ghodsi S, González-Castro A, Willis CV, Henderson BJ. The Impact of High or Low Doses of Nicotine in a Mouse Model of Vapor Self-Administration. Nicotine Tob Res 2024; 26:316-323. [PMID: 37531402 PMCID: PMC10882436 DOI: 10.1093/ntr/ntad136] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/18/2023] [Accepted: 07/31/2023] [Indexed: 08/04/2023]
Abstract
INTRODUCTION A wide variety of nicotine concentrations and formulations are available to users of electronic nicotine delivery systems (ENDS). This is increasingly true when considering the many flavors available with ENDS products. To date, there have been few preclinical investigations into the impact of nicotine doses, with and without flavors, on vaping-related behaviors. This present study evaluated how nicotine concentrations relevant to tank-based and pod-based ENDS, with and without flavors, impact reinforcement-related behavior in a mouse model. AIMS AND METHODS Adult male and female C57/BL6J mice were used in vapor-inhalation self-administration assays. Mice were assigned e-liquids containing 6 mg/mL or 60 mg/mL nicotine. Additional mice were assigned these nicotine doses with green apple or menthol flavorants. Mice were trained on fixed-ratio 1 for 10, 2-hour sessions, then five sessions at FR3, three progressive ratio sessions, and two FR3 sessions. RESULTS We observed male mice exhibited higher reinforcement-related behavior to menthol-flavored 6 mg/mL nicotine when compared to female mice. Males were only observed to have a menthol-induced enhancement of self-administration at 6 mg/mL nicotine and not 60 mg/mL nicotine. However, female mice exhibited significant menthol-induced increases in reinforcement-related behaviors with 60 mg/mL nicotine. CONCLUSIONS These data provide evidence that males and females exhibit different dose sensitivities to nicotine. These sex-dependent differences in nicotine sensitivity also indicate that flavor-induced enhancement in nicotine intake is dependent on the different doses for each sex. IMPLICATIONS There has been much discussion recently regarding the impact of flavors on vaping-related behavior. Our current study may support prior investigations that suggest flavors enhance the palatability of nicotine-containing products. However, this current study provides evidence that males and females exhibit different sensitivities to nicotine.
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Affiliation(s)
- Skylar Y Cooper
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
| | - Nathan A Olszewski
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
| | - Samuel Tetteh-Quarshie
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
| | - Sean P Hill
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
| | - Saaman Ghodsi
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
| | - Astrid González-Castro
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
| | - Clay V Willis
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
| | - Brandon J Henderson
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, Huntington, WV, USA
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Sato H, Satoh K, Nozaki K, Yugawa M, Kato T, Toyoda H, Katagiri A, Suda N, Adachi K. Reduced menthol sensitivity in a prodromal Parkinson's disease model induced by intranasal rotenone treatment. Front Cell Neurosci 2024; 18:1345651. [PMID: 38380382 PMCID: PMC10876781 DOI: 10.3389/fncel.2024.1345651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/19/2024] [Indexed: 02/22/2024] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor symptoms, and it is associated with several prodromal non-motor symptoms, including an impaired sense of smell, taste and touch. We previously reported that bitter taste impairments occur independently of olfactory impairments in an early-stage PD animal model using short-term intranasal rotenone-treated mice. Cool temperatures also affect bitter taste perception, but it remains unclear whether or not bitter taste impairments result from an altered sensitivity for intraoral cool stimuli. We examined disturbances in the intraoral menthol sensitivity, such as coolness at low concentrations of menthol, using a brief-access test. Once a day, one solution from the 7-concentration series of (-)-menthol (0-2.3 mM) or the bitter taste quinine-HCl (0.3 mM) was randomly presented 20 times for 10 s to water-deprived mice before and 1 week after rotenone treatment. The total number of licks within 20 times was significantly decreased with the presentation of 2.3 mM menthol and quinine-HCl, compared to distilled water in untreated mice, but not in rotenone-treated mice. The correlation between the licks for quinine-HCl and that for menthol was increased after rotenone treatment. In contrast, the 2-bottle choice test for 48 h clarified that menthol sensitivity was increased after rotenone treatment. Furthermore, a thermal place preference test revealed that seeking behavior toward a cold-floored room was increased in the rotenone-treated mice despite the unchanged plantar cutaneous cold sensitivity. These results suggest that taste impairments in this model mice are at least partly due to intraoral somatosensory impairments, accompanied by peripheral/central malfunction.
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Affiliation(s)
- Hajime Sato
- Division of Pharmacology, Meikai University School of Dentistry, Sakado, Japan
| | - Keitaro Satoh
- Division of Pharmacology, Meikai University School of Dentistry, Sakado, Japan
| | - Kazunori Nozaki
- Division of Medical Information, Osaka University Dental Hospital, Suita, Japan
| | - Misato Yugawa
- Division of Orthodontics, Meikai University School of Dentistry, Sakado, Japan
| | - Takafumi Kato
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Hiroki Toyoda
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Ayano Katagiri
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Naoto Suda
- Division of Orthodontics, Meikai University School of Dentistry, Sakado, Japan
| | - Kazunori Adachi
- Division of Pharmacology, Meikai University School of Dentistry, Sakado, Japan
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Jabba SV, Silinski P, Yang AY, Ouyang W, Jordt SE. Artificial Sweeteners in US-Marketed Oral Nicotine Pouch Products: Correlation with Nicotine Contents and Effects on Product Preference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.26.577472. [PMID: 38328200 PMCID: PMC10849646 DOI: 10.1101/2024.01.26.577472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Introduction Artificial sweeteners are listed as ingredients of oral nicotine pouches (ONPs), a new product category with rapidly growing market share. The exact sweetener contents of ONPs remain unknown. Artificial sweeteners in ONPs may facilitate initiation and encourage consumption behavior. Aims and Methods Artificial sweetener contents in major US-marketed ONP brands (Zyn, on!, Velo) were determined by Liquid Chromatography-Mass Spectrometry (LC-MS). Sweetener effects during the initiation of ONP consumption were modeled in single- and two-bottle tests, offering mice ONP extracts calibrated to contain nicotine levels similar to saliva of people who use smokeless tobacco. To examine the contribution of sweet taste perception, consumption behavior was compared between wild-type mice and mice deficient in the sweet taste receptor (Tas1r2-/-). Results Acesulfame-K was detected in on!, Zyn and Velo ONPs (~0.3-0.9 mg/pouch), including products marketed as "Unflavored" or "Flavor ban approved". In Velo ONPs, sweetened with sucralose (0.6-1.2 mg/pouch), higher nicotine strength products contained higher sucralose levels. Tas1r2-/- mice consumed less ONP extracts than wild-type mice in both sexes. ONP extracts with both higher nicotine and sweetener strengths were tolerated by wild-type mice, but produced stronger aversion in Tas1r2-/- mice. Conclusions ONPs contain significant amounts of artificial sweeteners, with some brands adding more sweetener to ONPs with higher nicotine strengths. Artificial sweeteners, at levels present in ONPs, increase nicotine consumption. Increasing sweetener contents facilitates consumption of ONPs with higher nicotine strengths. Sweetness is a key determinant of ONP use initiation, likely reducing the aversive sensory effects of nicotine and other ONP constituents. Implications Artificial sweeteners such as acesulfame-K or sucralose reduce aversion and facilitate initiation and continued consumption of ONPs. The marketing of some artificially sweetened ONPs as "Unflavored" of "Flavor ban-approved" suggests that the tobacco industry rejects sweet taste as a determinant for the presence of a characterizing flavor. Sweetness as imparted by artificial sweeteners in tobacco products needs to be addressed by regulators as a component of a characterizing flavor, with the aim to reduce product appeal and initiation by never users, and especially youth attracted to sweet flavors.
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Affiliation(s)
- Sairam V. Jabba
- Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA
- Yale Center for the Study of Tobacco Products (YCSTP), Department of Psychiatry, Yale School of Medicine, New Haven, CT
| | | | - Alicia Y. Yang
- Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA
| | - Wenyi Ouyang
- Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA
| | - Sven E. Jordt
- Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA
- Yale Center for the Study of Tobacco Products (YCSTP), Department of Psychiatry, Yale School of Medicine, New Haven, CT
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Leventhal AM, Tackett AP, Whitted L, Jordt SE, Jabba SV. Ice flavours and non-menthol synthetic cooling agents in e-cigarette products: a review. Tob Control 2023; 32:769-777. [PMID: 35483721 PMCID: PMC9613790 DOI: 10.1136/tobaccocontrol-2021-057073] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 04/19/2022] [Indexed: 01/21/2023]
Abstract
E-cigarettes with cooling flavours have diversified in ways that complicate tobacco control with the emergence of: (1) Ice-hybrid flavours (eg, 'Raspberry Ice') that combine cooling and fruity/sweet properties; and (2) Products containing non-menthol synthetic cooling agents (eg, Wilkinson Sword (WS), WS-3, WS-23 (termed 'koolada')). This paper reviews the background, chemistry, toxicology, marketing, user perceptions, use prevalence and policy implications of e-cigarette products with ice-hybrid flavours or non-menthol coolants. Scientific literature search supplemented with industry-generated and user-generated information found: (a) The tobacco industry has developed products containing synthetic coolants since 1974, (b) WS-3 and WS-23 are detected in mass-manufactured e-cigarettes (eg, PuffBar); (c) While safe for limited oral ingestion, inhalational toxicology and health effects from daily synthetic coolant exposure are unknown and merit scientific inquiry and attention from regulatory agencies; (d) Ice-hybrid flavours are marketed with themes incorporating fruitiness and/or coolness (eg, snow-covered raspberries); (e) WS-23/WS-3 concentrates also are sold as do-it-yourself additives, (f) Pharmacology research and user-generated and industry-generated information provide a premise to hypothesise that e-cigarette products with ice flavours or non-menthol cooling agents generate pleasant cooling sensations that mask nicotine's harshness while lacking certain aversive features of menthol-only products, (g) Adolescent and young adult use of e-cigarettes with ice-hybrid or other cooling flavours may be common and cross-sectionally associated with more frequent vaping and nicotine dependence in convenience samples. Evidence gaps in the epidemiology, toxicology, health effects and smoking cessation-promoting potential of using these products exist. E-cigarettes with ice flavours or synthetic coolants merit scientific and regulatory attention.
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Affiliation(s)
- Adam M Leventhal
- Institute for Addiction Science, University of Southern California, Los Angeles, California, USA
| | - Alayna P Tackett
- Department of Preventive Medicine, Keck School of Medicine University of Southern California, Los Angeles, California, USA
| | - Lauren Whitted
- Department of Preventive Medicine, Keck School of Medicine University of Southern California, Los Angeles, California, USA
| | - Sven Eric Jordt
- Anesthesiology, Duke University School of Medicine, Durham, North Carolina, USA
- Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Sairam V Jabba
- Anesthesiology, Duke University School of Medicine, Durham, North Carolina, USA
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Jabba SV, Erythropel HC, Woodrow JG, Anastas PT, O'Malley S, Krishnan-Sarin S, Zimmerman JB, Jordt SE. Synthetic cooling agent in oral nicotine pouch products marketed as 'Flavour-Ban Approved'. Tob Control 2023:tc-2023-058035. [PMID: 37380351 PMCID: PMC10753027 DOI: 10.1136/tc-2023-058035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/09/2023] [Indexed: 06/30/2023]
Abstract
BACKGROUND US sales of oral nicotine pouches (ONPs) have rapidly increased, with cool/mint-flavoured ONPs the most popular flavour category. Restrictions on sales of flavoured tobacco products have either been implemented or proposed by several US states and localities. Zyn, the most popular ONP brand, is marketing Zyn Chill and Zyn Smooth as 'Flavour-Ban Approved' or 'unflavoured', probably to evade flavour bans and increase product appeal. At present, it is unclear whether these ONPs are indeed free of flavour additives that can impart pleasant sensations such as cooling. METHODS Sensory cooling and irritant activities of 'Flavour-Ban Approved' Zyn ONPs, Chill and Smooth, along with minty varieties (Cool Mint, Peppermint, Spearmint, Menthol), were analysed by Ca2+ microfluorimetry in HEK293 cells expressing the cold/menthol (TRPM8) or menthol/irritant receptor (TRPA1). Flavour chemical content of these ONPs was analysed by gas chromatography/mass spectrometry. RESULTS Zyn Chill ONP extracts robustly activated TRPM8, with much higher efficacy (39%-53%) than the mint-flavoured ONPs. In contrast, mint-flavoured ONP extracts elicited stronger TRPA1 irritant receptor responses than Chill extracts. Chemical analysis demonstrated that Chill exclusively contained WS-3, an odourless synthetic cooling agent, while mint-flavoured ONPs contained WS-3 together with mint flavourants. CONCLUSIONS ONP products marketed as 'Flavour-Ban Approved' or 'unflavoured' contain flavouring agents, proving that the manufacturer's advertising is misleading. Synthetic coolants such as WS-3 can provide a robust cooling sensation with reduced sensory irritancy, thereby increasing product appeal and use. Regulators need to develop effective strategies for the control of odourless sensory additives used by the industry to bypass flavour bans.
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Affiliation(s)
- Sairam V Jabba
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina, USA
- Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Hanno C Erythropel
- Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
- Chemical and Environmental Engineering, Yale University, New Haven, Connecticut, USA
| | | | - Paul T Anastas
- Center for Green Chemistry & Green Engineering, Yale University, New Haven, Connecticut, USA
- Department of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, USA
| | - Stephanie O'Malley
- Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
- Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Suchitra Krishnan-Sarin
- Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
- Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Julie B Zimmerman
- Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
- Chemical and Environmental Engineering, Yale University, New Haven, Connecticut, USA
| | - Sven Eric Jordt
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina, USA
- Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
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Anderson MK, Whitted L, Mason TB, Pang RD, Tackett AP, Leventhal AM. Characterizing different-flavored e-cigarette solutions from user-reported sensory attributes and appeal. Exp Clin Psychopharmacol 2023; 31:46-56. [PMID: 35467923 PMCID: PMC9592684 DOI: 10.1037/pha0000563] [Citation(s) in RCA: 2] [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] [Indexed: 02/03/2023]
Abstract
Scientists and regulators need parsimonious methods of characterizing flavored e-cigarettes which may vary widely in both chemical flavoring constituents and marketing descriptors. This laboratory experiment characterized user-reported appeal and experience of five cross-cutting sensory attributes (sweetness, bitterness, smoothness, harshness, coolness) of 10 common e-cigarette flavors. In a within-subject double-blind single-visit protocol, current nicotine/tobacco product users (N = 119) self-administered a single puff of each e-liquid flavor via a pod-style device and rated its appeal and sensory attributes on 0-100 scales. Custom-manufactured e-liquids, nicotine concentration: M (SD) = 23.4 (0.9) mg/mL, representative of commonly marketed fruit (green apple, strawberry), dessert (dark chocolate, vanilla), mint (peppermint, spearmint), nonmint cooling (menthol, koolada), and tobacco (subtle tobacco, full-flavored tobacco) flavor descriptors were used and their constituents were independently analyzed. Results largely demonstrated that a flavor's sensory attributes concorded with its marketed flavor descriptor. Among the 10 flavors, vanilla was rated sweetest (B[difference vs. mean of 9 other flavors] = 14.44, 95% CI [10.84, 18.03]), full-flavored tobacco was most bitter, B = 8.34, 95% CI [4.73, 11.96], subtle tobacco was most harsh, B = 5.69, 95% CI [1.70, 9.68], and peppermint scored highest in both smoothness, B = 6.98, 95% CI [3.13, 10.82], and coolness, B = 29.25, 95% CI [25.50, 33.01]. Flavors with higher appeal ratings tended to be sweeter, smoother, cooler, and less bitter and harsh. Chemical analysis found numerous flavoring constituents among study products without any clear differentiation of chemicals being present in particular flavor categories, which underscores the utility of using sensory ratings to characterize different-flavored e-cigarettes over and above constituent analyses. Characterizing e-cigarette flavors by subjective sensory attributes may be useful in future research and regulatory activities. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Affiliation(s)
- Marissa K. Anderson
- Department of Population and Public Health Sciences, Keck School of Medicine of USC
| | - Lauren Whitted
- Department of Population and Public Health Sciences, Keck School of Medicine of USC
| | - Tyler B. Mason
- Department of Population and Public Health Sciences, Keck School of Medicine of USC
| | - Raina D. Pang
- Department of Population and Public Health Sciences, Keck School of Medicine of USC
- Institute for Addiction Science, University of Southern California
- Department of Psychology, University of Southern California
| | - Alayna P. Tackett
- Department of Population and Public Health Sciences, Keck School of Medicine of USC
- Institute for Addiction Science, University of Southern California
| | - Adam M. Leventhal
- Department of Population and Public Health Sciences, Keck School of Medicine of USC
- Institute for Addiction Science, University of Southern California
- Department of Psychology, University of Southern California
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7
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Brown JL, Neptune E. Role of Menthol and Other Flavors on Tobacco and Nicotine Product Use. Respir Med 2023. [DOI: 10.1007/978-3-031-24914-3_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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Akinola LS, Rahman Y, Ondo O, Cobb CO, Holt AK, Peace MR, Damaj MI. Impact of tobacco flavoring on oral nicotine consumption in C57BL/6J mice. Drug Alcohol Depend 2022; 241:109685. [PMID: 36370533 DOI: 10.1016/j.drugalcdep.2022.109685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND The continued use of flavors in tobacco products has been a prominent factor in their popularity, yet little is known regarding their role in nicotine dependence. This study aimed to investigate the impact of tobacco flavoring on oral nicotine consumption in mice using the two-bottle choice (2BC) test and assessed the potential impact of age and sex in their interactions. METHODS Adolescent and adult male and female C57BL/6J mice were used. First, voluntary consumption of tobacco flavor concentrate from a commercial electronic cigarette liquid vendor (Avail Vapor LLC) was measured; then, the effects of tobacco flavoring in combination with nicotine were examined. In one approach, tobacco flavor concentration was kept constant while nicotine concentration varied, and in the second, nicotine was kept constant while the tobacco flavor concentration varied. RESULTS Overall, tobacco flavoring decreased oral nicotine consumption in mice, and its effects were sex- and age-dependent. Although females consumed the tobacco-flavored solution at a slightly higher rate than males, male mice were more sensitive to the effects of the combination (nicotine + tobacco). Furthermore, adolescent mice showed a starker reduction in nicotine consumption in the presence of tobacco flavoring compared to adult mice. This attenuation was most likely due to a basal aversion to the tobacco flavoring itself, thus, creating a negative synergistic effect with nicotine. CONCLUSIONS Tobacco flavoring increases aversion to nicotine in the 2BC test in C57BL6J mice, suggesting that some flavors may diminish rather than enhance oral nicotine consumption in rodents.
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Affiliation(s)
- Lois S Akinola
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA.
| | - Yumna Rahman
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Olivia Ondo
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Caroline O Cobb
- Department of Psychology and Center for the Study of Tobacco Products, Virginia Commonwealth University, Richmond, VA, USA
| | - Alaina K Holt
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Michelle R Peace
- Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, USA
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
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Olszewski NA, Tetteh-Quarshie S, Henderson BJ. Understanding the Impact of Flavors on Vaping and Nicotine Addiction-Related Behaviors. Curr Behav Neurosci Rep 2022. [DOI: 10.1007/s40473-022-00253-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Li Z, Zhang H, Wang Y, Li Y, Li Q, Zhang L. The distinctive role of menthol in pain and analgesia: Mechanisms, practices, and advances. Front Mol Neurosci 2022; 15:1006908. [PMID: 36277488 PMCID: PMC9580369 DOI: 10.3389/fnmol.2022.1006908] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Menthol is an important flavoring additive that triggers a cooling sensation. Under physiological condition, low to moderate concentrations of menthol activate transient receptor potential cation channel subfamily M member 8 (TRPM8) in the primary nociceptors, such as dorsal root ganglion (DRG) and trigeminal ganglion, generating a cooling sensation, whereas menthol at higher concentration could induce cold allodynia, and cold hyperalgesia mediated by TRPM8 sensitization. In addition, the paradoxical irritating properties of high concentrations of menthol is associated with its activation of transient receptor potential cation channel subfamily A member 1 (TRPA1). Under pathological situation, menthol activates TRPM8 to attenuate mechanical allodynia and thermal hyperalgesia following nerve injury or chemical stimuli. Recent reports have recapitulated the requirement of central group II/III metabotropic glutamate receptors (mGluR) with endogenous κ-opioid signaling pathways for menthol analgesia. Additionally, blockage of sodium channels and calcium influx is a determinant step after menthol exposure, suggesting the possibility of menthol for pain management. In this review, we will also discuss and summarize the advances in menthol-related drugs for pathological pain treatment in clinical trials, especially in neuropathic pain, musculoskeletal pain, cancer pain and postoperative pain, with the aim to find the promising therapeutic candidates for the resolution of pain to better manage patients with pain in clinics.
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Affiliation(s)
- Ziping Li
- The Graduate School, Tianjin Medical University, Tianjin, China
| | - Haoyue Zhang
- The Graduate School, Tianjin Medical University, Tianjin, China
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yigang Wang
- The Graduate School, Tianjin Medical University, Tianjin, China
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yize Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Qing Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Qing Li,
| | - Linlin Zhang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- *Correspondence: Linlin Zhang,
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Johnson NL, Patten T, Ma M, De Biasi M, Wesson DW. Chemosensory Contributions of E-Cigarette Additives on Nicotine Use. Front Neurosci 2022; 16:893587. [PMID: 35928010 PMCID: PMC9344001 DOI: 10.3389/fnins.2022.893587] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
While rates of smoking combustible cigarettes in the United States have trended down in recent years, use of electronic cigarettes (e-cigarettes) has dramatically increased, especially among adolescents. The vast majority of e-cigarette users consume "flavored" products that contain a variety of chemosensory-rich additives, and recent literature suggests that these additives have led to the current "teen vaping epidemic." This review, covering research from both human and rodent models, provides a comprehensive overview of the sensory implications of e-cigarette additives and what is currently known about their impact on nicotine use. In doing so, we specifically address the oronasal sensory contributions of e-cigarette additives. Finally, we summarize the existing gaps in the field and highlight future directions needed to better understand the powerful influence of these additives on nicotine use.
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Affiliation(s)
- Natalie L. Johnson
- Department of Pharmacology and Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States
| | - Theresa Patten
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Minghong Ma
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Mariella De Biasi
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Daniel W. Wesson
- Department of Pharmacology and Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States
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Akinola LS, Rahman Y, Ondo O, Gonzales J, Bagdas D, Jackson A, Davidson-Wert N, Damaj MI. Genotypic Differences in the Effects of Menthol on Nicotine Intake and Preference in Mice. Front Neurosci 2022; 16:905330. [PMID: 35769694 PMCID: PMC9234577 DOI: 10.3389/fnins.2022.905330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Menthol has been shown to exacerbate elements of nicotine addiction in humans and rodents; however, the mechanisms mediating its effects are not fully understood. This study examined the impact of genetic factors in menthol’s effects on oral nicotine consumption by comparing two inbred mouse strains with differing sensitivities to nicotine. C57BL/6J (B6J) mice are nicotine-preferring, while DBA/2J (D2J) mice are not. While the effects of menthol on oral nicotine consumption have been highlighted in B6J mice, it is unknown if they extend to the D2J strain as well. Consequently, adolescent (PND 21) and adult (PND 63), male and female D2J mice were subjected to the nicotine two-bottle choice (2BC) paradigm with orally and systemically administered menthol. Then, we evaluated its impact on nicotine pharmacological responses in conditioned reward and nociception after systemic administration and, lastly, investigated the potential involvement of the TAAR1 gene and α7 nAChRs in menthol’s effects. Menthol failed to enhance oral nicotine consumption in adult and adolescent female and male D2J mice. Moreover, this lack in effect was not due to nicotine concentration, oral aversion to menthol, or basal preference for nicotine. Menthol also failed to augment nicotine reward or enhance nicotine-induced antinociception in D2J mice, demonstrating that genetic background plays a significant role in sensitivity to menthol’s effects on nicotine. Furthermore, TAAR1 or α7 nAChRs did not seem to mediate menthol’s differential effects in D2J mice. These findings support the existence of genotype-specific mechanisms that may contribute to the variable effects of menthol in different populations.
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Affiliation(s)
- Lois S. Akinola
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, United States
- *Correspondence: Lois S. Akinola,
| | - Yumna Rahman
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, United States
| | - Olivia Ondo
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, United States
| | - Jada Gonzales
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, United States
| | - Deniz Bagdas
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, United States
- Yale Tobacco Center of Regulatory Science, Yale School of Medicine, New Haven, CT, United States
| | - Asti Jackson
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, United States
- Yale Tobacco Center of Regulatory Science, Yale School of Medicine, New Haven, CT, United States
| | - Nicole Davidson-Wert
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, United States
| | - M. Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, United States
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13
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McKie GL, Medak KD, Shamshoum H, Wright DC. Topical application of the pharmacological cold mimetic menthol stimulates brown adipose tissue thermogenesis through a TRPM8, UCP1, and norepinephrine dependent mechanism in mice housed at thermoneutrality. FASEB J 2022; 36:e22205. [PMID: 35157333 DOI: 10.1096/fj.202101905rr] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/27/2022] [Accepted: 01/31/2022] [Indexed: 12/29/2022]
Abstract
Increasing whole-body energy expenditure via the pharmacological activation of uncoupling protein 1 (UCP1)-dependent brown adipose tissue (BAT) thermogenesis is a promising weight management strategy, yet most therapeutics studied in rodents to date either induce compensatory increases in energy intake, have thermogenic effects that are confounded by sub-thermoneutral housing temperatures or are not well tolerated in humans. Here, we sought to determine whether the non-invasive topical application of the pharmacological cold mimetic and transient receptor potential (TRP) cation channel subfamily M member 8 (TRPM8) agonist L-menthol (MNTH), could be used to stimulate BAT thermogenesis and attenuate weight gain in mice housed at thermoneutrality. Using three different strains of mice and multiple complimentary approaches to quantify thermogenesis in vivo, coupled with ex vivo models to quantify direct thermogenic effects, we were able to convincingly demonstrate the following: (1) acute topical MNTH application induces BAT thermogenesis in a TRPM8- and UCP1-dependent manner; (2) MNTH-induced BAT thermogenesis is sufficient to attenuate weight gain over time without affecting energy intake in lean and obese mice; (3) the ability of topical MNTH application to stimulate BAT thermogenesis is mediated, in part, by a central mechanism involving the release of norepinephrine. These data collectively suggest that topical application of MNTH may be a promising weight management strategy.
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Affiliation(s)
- Greg L McKie
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Kyle D Medak
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Hesham Shamshoum
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David C Wright
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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14
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Jabba SV, Erythropel HC, Torres DG, Delgado LA, Woodrow JG, Anastas PT, Zimmerman JB, Jordt SE. Synthetic Cooling Agents in US-marketed E-cigarette Refill Liquids and Popular Disposable E-cigarettes: Chemical Analysis and Risk Assessment. Nicotine Tob Res 2022; 24:1037-1046. [PMID: 35167696 PMCID: PMC9199944 DOI: 10.1093/ntr/ntac046] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 12/06/2021] [Accepted: 02/12/2022] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Menthol, through its cooling and pleasant sensory effects, facilitates smoking and tobacco product initiation, resulting in the high popularity of mint/menthol-flavored E-cigarettes. More recently, E-cigarette vendors started marketing synthetic cooling agents as additives that impart a cooling effect but lack a characteristic minty odor. Knowledge about content of synthetic coolants in US-marketed E-cigarette products and associated health risks is limited. AIMS AND METHODS E-liquid vendor sites were searched with the terms "koolada", "kool/cool", "ice", or WS-3/WS-23, denoting individual cooling agents, and relevant refill E-liquids were purchased. "Ice" flavor varieties of Puffbar, the most popular disposable E-cigarette brand, were compared with non-"Ice" varieties. E-liquids were characterized, and synthetic coolants quantified using GC/MS. Margin of exposure (MOE), a risk assessment parameter, was calculated to assess the risk associated with synthetic coolant exposure from E-cigarette use. RESULTS WS-3 was detected in 24/25 refill E-liquids analyzed. All Puffbar flavor varieties contained either WS-23 (13/14) or WS-3 (5/14), in both "Ice"- and non-"Ice" flavors. Modeling consumption of WS-3 from vaped E-liquids, resulted in MOEs below the safe margin of 100 for most daily use scenarios. MOEs for WS-23 were <100 for 10/13 Puffbar flavors in all use scenarios. Puffbar power specifications are identical to Juul devices. CONCLUSIONS Synthetic cooling agents (WS-3/WS-23) were present in US-marketed E-cigarettes, at levels that may result in consumer exposures exceeding safety thresholds set by regulatory agencies. Synthetic coolants are not only found in mint- or menthol-flavored products but also in fruit- and candy-flavored products, including popular disposable E-cigarette products such as Puffbar. IMPLICATIONS Synthetic cooling agents are widely used in "kool/cool"- and "ice"-flavored E-liquids and in E-liquids without these labels, both as a potential replacement for menthol or to add cooling "notes" to nonmenthol flavors. These agents may be used to bypass current and future regulatory limits on menthol content in tobacco products, and not just E-cigarettes. Because synthetic cooling agents are odorless, they may not fall under the category of "characterizing flavor", potentially circumventing regulatory measures based on this concept. Regulators need to consider the additional health risks associated with exposure to synthetic cooling agents.
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Affiliation(s)
| | | | | | | | | | - Paul T Anastas
- Environmental Health Sciences Department, School of Public Health, Yale University, New Haven, CT, USA
| | - Julie B Zimmerman
- Yale Center for the Study of Tobacco Products (YCSTP), Department of Psychiatry, Yale School of Medicine, New Haven, CT,USA,Department of Chemical and Environmental Engineering, Yale University, New Haven, CT,USA
| | - Sven-Eric Jordt
- Corresponding Author: Sven-Eric Jordt, PhD, Department of Anesthesiology, Duke University School of Medicine, 3 Genome Ct., Durham, NC 27710-3094, USA. E-mail:
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15
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Bagdas D, Kebede N, Zepei AM, Harris L, Minanov K, Picciotto MR, Addy NA. Animal Models to Investigate the Impact of Flavors on Nicotine Addiction and Dependence. Curr Neuropharmacol 2022; 20:2175-2201. [PMID: 35611777 PMCID: PMC9886843 DOI: 10.2174/1570159x20666220524120231] [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] [Received: 12/26/2021] [Revised: 04/17/2022] [Accepted: 05/22/2022] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Tobacco use in humans is a long-standing public health concern. Flavors are common additives in tobacco and alternative tobacco products, added to mask nicotine's harsh orosensory effects and increase the appeal of these products. Animal models are integral for investigating nicotine use and addiction and are helpful for understanding the effects of flavor additives on the use of nicotine delivery products. OBJECTIVE This review focuses on preclinical models to evaluate the contribution of flavor additives to nicotine addiction. MATERIALS AND METHODS An electronic literature search was conducted by authors up to May 2022. Original articles were selected. RESULTS The behavioral models of rodents described here capture multiple dimensions of human flavored nicotine use behaviors, including advantages and disadvantages. CONCLUSION The consensus of the literature search was that human research on nicotine use behavior has not caught up with fast-changing product innovations, marketing practices, and federal regulations. Animal models are therefore needed to investigate mechanisms underlying nicotine use and addiction. This review provides a comprehensive overvie.
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Affiliation(s)
- Deniz Bagdas
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
- Yale Tobacco Center of Regulatory Science, Yale School of Medicine, New Haven, CT, USA
| | - Nardos Kebede
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Andy Ma Zepei
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Lilley Harris
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Karina Minanov
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Marina R. Picciotto
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
- Yale Tobacco Center of Regulatory Science, Yale School of Medicine, New Haven, CT, USA
| | - Nii A. Addy
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
- Yale Tobacco Center of Regulatory Science, Yale School of Medicine, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
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16
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Bagdas D, Rupprecht LE, Nunes EJ, Schillinger E, Immanuel JJ, Addy NA. Evaluation of Flavor Effects on Oral Nicotine Liking and/or Disliking Using the Taste Reactivity Test in Rats. Nicotine Tob Res 2021; 24:753-760. [PMID: 34918123 DOI: 10.1093/ntr/ntab241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 09/01/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Tobacco product flavors may change the sensory properties of nicotine, such as taste and olfactory cues, which may alter nicotine reward and aversion and nicotine taking behavior. The hedonic or aversive value of a taste stimulus can be evaluated by examining affective orofacial movements in rodents. AIMS AND METHODS We characterized taste responses to various oral nicotine concentrations using the taste reactivity test in rats. We also evaluated the impact of menthol and benzaldehyde (cherry, almond) flavorants on both ingestive and aversive responses to oral nicotine. Adult Sprague-Dawley rats (n = 5-10 per sex per group) were implanted with intraoral catheters and received 20 infusions (200 µl/ea). Nicotine (1-100 µg/mL) was evaluated in taste reactivity test to determine taste responses to nicotine. Later, the effects of menthol (50 µg/mL) and benzaldehyde (100 µg/mL) on the taste responses to nicotine were determined. RESULTS Nicotine at low concentrations (3 µg/mL in males, 1 µg/mL in females) elicited significantly greater ingestive responses compared with water, whereas higher nicotine concentrations (≥30 µg/mL in males, ≥10 µg/mL in females) elicited significant aversive reactions. Thus, intraoral nicotine induced both hedonic and aversive responses in a concentration- and sex-dependent manner. Females were more sensitive to nicotine's concentration. The addition of menthol or benzaldehyde significantly increased the hedonic responses to nicotine, and significantly decreased the aversive nicotine responses. CONCLUSIONS Oral nicotine induces both hedonic and aversive taste responses, which may represent liking and disliking. Menthol and benzaldehyde can alter the orosensory experience of nicotine, which may influence nicotine's abuse liability. IMPLICATIONS Our work represents a model to study impact of flavors on oral nicotine liking and disliking responses in rats. Moreover, our findings show that menthol and benzaldehyde alter the orosensory experience of nicotine, suggesting that both could influence nicotine's abuse liability.
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Affiliation(s)
- Deniz Bagdas
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Laura E Rupprecht
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Eric J Nunes
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Emma Schillinger
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Judah J Immanuel
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Nii A Addy
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Yale Tobacco Center of Regulatory Science, Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA.,Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
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17
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Cooper SY, Akers AT, Journigan VB, Henderson BJ. Novel Putative Positive Modulators of α4β2 nAChRs Potentiate Nicotine Reward-Related Behavior. Molecules 2021; 26:4793. [PMID: 34443380 PMCID: PMC8398432 DOI: 10.3390/molecules26164793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 11/18/2022] Open
Abstract
The popular tobacco and e-cigarette chemical flavorant (-)-menthol acts as a nonselective, noncompetitive antagonist of nicotinic acetylcholine receptors (nAChRs), and contributes to multiple physiological effects that exacerbates nicotine addiction-related behavior. Menthol is classically known as a TRPM8 agonist; therefore, some have postulated that TRPM8 antagonists may be potential candidates for novel nicotine cessation pharmacotherapies. Here, we examine a novel class of TRPM8 antagonists for their ability to alter nicotine reward-related behavior in a mouse model of conditioned place preference. We found that these novel ligands enhanced nicotine reward-related behavior in a mouse model of conditioned place preference. To gain an understanding of the potential mechanism, we examined these ligands on mouse α4β2 nAChRs transiently transfected into neuroblastoma-2a cells. Using calcium flux assays, we determined that these ligands act as positive modulators (PMs) on α4β2 nAChRs. Due to α4β2 nAChRs' important role in nicotine dependence, as well as various neurological disorders including Parkinson's disease, the identification of these ligands as α4β2 nAChR PMs is an important finding, and they may serve as novel molecular tools for future nAChR-related investigations.
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Affiliation(s)
- Skylar Y. Cooper
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25703, USA; (S.Y.C.); (A.T.A.); (V.B.J.)
| | - Austin T. Akers
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25703, USA; (S.Y.C.); (A.T.A.); (V.B.J.)
| | - Velvet Blair Journigan
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25703, USA; (S.Y.C.); (A.T.A.); (V.B.J.)
- Department of Pharmaceutical Sciences, School of Pharmacy, Marshall University, Huntington, WV 25701, USA
| | - Brandon J. Henderson
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25703, USA; (S.Y.C.); (A.T.A.); (V.B.J.)
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18
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Henderson BJ, Cooper SY. Nicotine formulations impact reinforcement-related behaviors in a mouse model of vapor self-administration. Drug Alcohol Depend 2021; 224:108732. [PMID: 33930641 PMCID: PMC8180495 DOI: 10.1016/j.drugalcdep.2021.108732] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Electronic nicotine delivery systems (ENDS) differ from combustible cigarettes given that nicotine-salt or nicotine-freebase may be used depending on the product. We have investigated how nicotine-salt and freebase formulations alter e-Vape® self-administration (EVSA) behavior and plasma cotinine levels in male and female mice. METHODS Adult C57/BL6 J mice were used in EVSA and assigned vaping e-liquids (50:50 PGVG, 6 mg/mL nicotine-freebase, or 6 mg/mL nicotine-salt). Mice were escalated on a fixed ratio 1 (FR1) schedule in daily 2 h sessions and then transitioned to a FR3 to examine reinforcement-related behaviors. RESULTS Here we observed that mice assigned nicotine-salt exhibited increased EVSA on a FR3 schedule compared to nicotine-freebase. Additionally, mice assigned nicotine-salt exhibited higher plasma cotinine concentrations following delivery-controlled passive-inhalation sessions. CONCLUSIONS These data provide evidence nicotine-salt formulations may contribute to greater reinforcement-related behavior and highlight the need for further investigations regarding nicotine formulation in ENDS.
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Affiliation(s)
- Brandon J. Henderson
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, 1700 3rd ave, Huntington, WV 25703, USA,Corresponding Author: Brandon J. Henderson, PhD, Department of Biomedical Sciences Joan C Edwards School of Medicine at Marshall University 1700 3rd Ave, 410 BBSC, Huntington, WV 25703 Phone: 304-696-7316
| | - Skylar Y. Cooper
- Department of Biomedical Sciences, Joan C Edwards School of Medicine at Marshall University, 1700 3rd ave, Huntington, WV 25703, USA
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19
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Rhyu MR, Kim Y, Lyall V. Interactions between Chemesthesis and Taste: Role of TRPA1 and TRPV1. Int J Mol Sci 2021; 22:ijms22073360. [PMID: 33806052 PMCID: PMC8038011 DOI: 10.3390/ijms22073360] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
In addition to the sense of taste and olfaction, chemesthesis, the sensation of irritation, pungency, cooling, warmth, or burning elicited by spices and herbs, plays a central role in food consumption. Many plant-derived molecules demonstrate their chemesthetic properties via the opening of transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) channels. TRPA1 and TRPV1 are structurally related thermosensitive cation channels and are often co-expressed in sensory nerve endings. TRPA1 and TRPV1 can also indirectly influence some, but not all, primary taste qualities via the release of substance P and calcitonin gene-related peptide (CGRP) from trigeminal neurons and their subsequent effects on CGRP receptor expressed in Type III taste receptor cells. Here, we will review the effect of some chemesthetic agonists of TRPA1 and TRPV1 and their influence on bitter, sour, and salt taste qualities.
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Affiliation(s)
- Mee-Ra Rhyu
- Korea Food Research Institute, Wanju-gun 55365, Korea;
- Correspondence: ; Tel.: +82-63-219-9268
| | - Yiseul Kim
- Korea Food Research Institute, Wanju-gun 55365, Korea;
| | - Vijay Lyall
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA 23298, USA;
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20
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Wickham RJ. The Biological Impact of Menthol on Tobacco Dependence. Nicotine Tob Res 2021; 22:1676-1684. [PMID: 31867627 DOI: 10.1093/ntr/ntz239] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/17/2019] [Indexed: 12/19/2022]
Abstract
In the 1920s, tobacco companies created a marketing campaign for what would one day be their most profitable series of products: mentholated tobacco cigarettes. Menthol provides the smoker with a pleasant mint flavor in addition to a cooling sensation of the mouth, throat, and lungs, giving relief from the painful irritation caused by tobacco smoke. Promising a healthier cigarette using pictures of doctors in white coats and even cartoon penguins, tobacco companies promoted these cigarettes to young, beginner smokers and those with respiratory health concerns. Today, smoking tobacco cigarettes causes one in five US Americans to die prematurely, crowning it as the leading cause of preventable death. In contrast to the dubious health claims by tobacco companies, mentholated cigarettes are in fact more addictive. Smokers of mentholated cigarettes have lower successful quit rates and in some cases are resistant to both behavioral and pharmacological treatment strategies. There is now considerable evidence, especially in the last 5 years, that suggest menthol might influence the addictive potential of nicotine-containing tobacco products via biological mechanisms. First, menthol alters the expression, stoichiometry, and function of nicotinic receptors. Second, menthol's chemosensory properties operate to mask aversive properties of using tobacco products. Third, menthol's chemosensory properties aid in serving as a conditioned cue that can both enhance nicotine intake and drive relapse. Fourth, menthol alters nicotine metabolism, increasing its bioavailability. This review discusses emerging evidence for these mechanisms, with an emphasis on preclinical findings that may shed light on why menthol smokers exhibit greater dependence. IMPLICATIONS Mentholated cigarettes have been shown to have greater addictive potential than their nonmentholated counterparts. Evidence is pointing toward multiple mechanisms of action by which menthol may alter tobacco dependence. Understanding menthol's biological functions as it pertains to nicotine dependence will be helpful in crafting novel pharmacotherapies that might better serve menthol smokers. In addition, a better understanding of menthol's pharmacology as it relates to tobacco dependence will be valuable for informing policy decisions on the regulation of mentholated cigarettes.
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Affiliation(s)
- Robert J Wickham
- Department of Psychology, Elizabethtown College, Elizabethtown, PA
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21
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Denlinger-Apte RL, Cassidy RN, Carey KB, Kahler CW, Bickel WK, O'Connor R, Thussu S, Tidey JW. The impact of menthol flavoring in combusted tobacco on alternative product purchasing: A pilot study using the Experimental Tobacco Marketplace. Drug Alcohol Depend 2021; 218:108390. [PMID: 33213974 PMCID: PMC7750267 DOI: 10.1016/j.drugalcdep.2020.108390] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/01/2020] [Accepted: 10/24/2020] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Menthol cigarette smokers may switch to other combusted products like menthol little cigars and cigarillos (LCCs) or switch to non-combusted products like menthol vapes if menthol cigarettes are banned or otherwise restricted. This pilot study used a behavioral economics task to understand (a) menthol cigarette demand across a range of increasing prices in the context of available alternative products and (b) how the availability of menthol LCCs affected cigarette demand and alternative product substitution. METHODS Menthol smokers completed the Experimental Tobacco Marketplace task during two sessions. Cigarettes, LCCs, smokeless tobacco, vapes, and medicinal nicotine were available from an online store. The price of menthol cigarettes increased across trials while the prices of the alternative products remained constant. Menthol LCCs were available in one session and excluded in the other. Cross-price elasticity beta estimates identified significant product substitutes. RESULTS When menthol LCCs were available, increasing the price of menthol cigarettes led to substitution with non-menthol cigarettes (β = 0.65, 95%CI = 0.34, 0.96), menthol little cigars (β = 0.39, 95%CI = 0.08, 0.70), and menthol vapes (β = 0.26, 95%CI = 0.16, 0.35). When menthol LCCs were not available, increasing the price of menthol cigarettes led to substitution with non-menthol cigarettes (β = 0.59, 95% CI = 0.08, 1.11), non-menthol cigarillos (β = 0.62, 95%CI = 0.19, 1.04), and menthol vapes (β = 0.13, 95%CI = 0.08, 0.18). CONCLUSIONS As the price of menthol cigarettes increased, demand for menthol cigarettes decreased and demand for combusted and non-combusted products increased, indicating significant substitution for menthol cigarettes. Policies targeting menthol combusted tobacco could result in some menthol smokers switching to non-combusted products like vaping devices.
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Affiliation(s)
- Rachel L Denlinger-Apte
- Department of Social Sciences and Health Policy, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
| | - Rachel N Cassidy
- Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI, 02912, USA.
| | - Kate B Carey
- Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI, 02912, USA.
| | - Christopher W Kahler
- Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI, 02912, USA.
| | - Warren K Bickel
- Fralin Biomedical Research Institute, Virginia Tech, Roanoke, VA, 24016, USA.
| | - Richard O'Connor
- Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, NY, 14263, USA. Richard.O'
| | - Shreeya Thussu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - Jennifer W Tidey
- Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI, 02912, USA.
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22
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Cooper SY, Henderson BJ. The Impact of Electronic Nicotine Delivery System (ENDS) Flavors on Nicotinic Acetylcholine Receptors and Nicotine Addiction-Related Behaviors. Molecules 2020; 25:E4223. [PMID: 32942576 PMCID: PMC7571084 DOI: 10.3390/molecules25184223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/11/2020] [Accepted: 09/13/2020] [Indexed: 12/18/2022] Open
Abstract
Over the past two decades, combustible cigarette smoking has slowly declined by nearly 11% in America; however, the use of electronic cigarettes has increased tremendously, including among adolescents. While nicotine is the main addictive component of tobacco products and a primary concern in electronic cigarettes, this is not the only constituent of concern. There is a growing market of flavored products and a growing use of zero-nicotine e-liquids among electronic cigarette users. Accordingly, there are few studies that examine the impact of flavors on health and behavior. Menthol has been studied most extensively due to its lone exception in combustible cigarettes. Thus, there is a broad understanding of the neurobiological effects that menthol plus nicotine has on the brain including enhancing nicotine reward, altering nicotinic acetylcholine receptor number and function, and altering midbrain neuron excitability. Although flavors other than menthol were banned from combustible cigarettes, over 15,000 flavorants are available for use in electronic cigarettes. This review seeks to summarize the current knowledge on nicotine addiction and the various brain regions and nicotinic acetylcholine receptor subtypes involved, as well as describe the most recent findings regarding menthol and green apple flavorants, and their roles in nicotine addiction and vaping-related behaviors.
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Affiliation(s)
| | - Brandon J. Henderson
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25703, USA;
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Bagdas D, Cam B, Gul Z, Scott MM, Tyndale RF, Buyukuysal RL, Damaj MI, Gurun MS. Impact of Menthol on Oral Nicotine Consumption in Female and Male Sprague Dawley Rats. Nicotine Tob Res 2020; 22:196-203. [PMID: 30753589 DOI: 10.1093/ntr/ntz019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 02/05/2019] [Indexed: 12/18/2022]
Abstract
INTRODUCTION One of the preferable flavors in oral nicotine delivery systems is menthol which masks the harshness of tobacco. However, possible interactions between oral menthol and nicotine on intake and preference remain unclear. Therefore, we aimed to determine the impact of menthol on oral nicotine consumption. METHODS Adult Sprague Dawley female and male rats (n = 8 per group) were given a choice of water or drug solution by using two-bottle free choice paradigm for 2 weeks: vehicle (5% ethanol), nicotine (20 mg/L), menthol (1 g/L) and mentholated nicotine groups. At the end of the study, plasma nicotine levels were determined. RESULTS When rats were given a choice of nicotine or water, nicotine intake was similar between female and male rats. Menthol addition to nicotine solution significantly increased nicotine intake and preference in male but not female rats without a considerable effect on total fluid intake and body weight change in either sex. The average nicotine intake in male rats was 0.5 ± 0.05 and 1.4 ± 0.12 mg/kg/day for nicotine and menthol-nicotine combination (p < .05), respectively. The average nicotine intake in female rats was 0.6 ± 0.05 and 0.6 ± 0.03 mg/kg/day for nicotine and menthol-nicotine combination (p > .05), respectively. Plasma nicotine levels were not significantly different between the groups in either male (nicotine group: 20.8 ± 4.9, mentholated nicotine group: 31.9 ± 3.2 ng/mL) or female (nicotine group: 24.0 ± 3.3, mentholated nicotine group: 17.8 ± 2.9 ng/mL) rats (p > .05). CONCLUSIONS Menthol increases oral nicotine consumption in male, but not female, rats. IMPLICATIONS This study may provide data on the co-use of menthol and nicotine in smokeless tobacco, particularly oral dissolvable tobacco products.
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Affiliation(s)
- Deniz Bagdas
- The Center for the Study for Tobacco Products, Virginia Commonwealth University, Richmond, VA.,Department of Psychiatry, Yale School of Medicine, New Haven, CT
| | - Betul Cam
- Department of Emergency Medicine, Bagcilar Training and Research Hospital, Istanbul, Turkey
| | - Zulfiye Gul
- Department of Pharmacology, School of Medicine, Bahcesehir University, Istanbul, Turkey
| | - Michael M Scott
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Departments of Pharmacology and Toxicology, and Psychiatry, University of Toronto, Toronto, ON, Canada
| | | | - M Imad Damaj
- The Center for the Study for Tobacco Products, Virginia Commonwealth University, Richmond, VA.,Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA
| | - Mine Sibel Gurun
- Department of Pharmacology, Faculty of Medicine, Uludag University, Bursa, Turkey
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Bagdas D, Jackson A, Carper M, Chen RYT, Akinola LS, Damaj MI. Impact of menthol on nicotine intake and preference in mice: Concentration, sex, and age differences. Neuropharmacology 2020; 179:108274. [PMID: 32827516 DOI: 10.1016/j.neuropharm.2020.108274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 08/09/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022]
Abstract
Menthol has been shown to contribute to the appeal of tobacco products in humans. However, factors such as sex, age and menthol concentration remain unclear in the interaction between menthol and nicotine. To understand these factors, we utilized a mouse model to determine the impact of menthol on oral nicotine consumption. A range of menthol concentrations (oral and systemic) were tested with or without oral nicotine using the two-bottle choice paradigm in adolescent and adult female and male C57BL/6J mice. Moreover, genetically modified mice were used to investigate the role of α7 nicotinic acetylcholine receptors (nAChRs) on the effects of menthol. Menthol addition to nicotine solution increased oral nicotine consumption in C57BL/6J mice in a sex- and menthol concentration-dependent manner. At lower menthol concentrations, female mice demonstrated an enhancement of nicotine consumption and male mice showed a similar behavior at higher menthol concentrations. Menthol drinking alone was only significantly different by sex at 60 μg/ml menthol concentration where female mice had higher menthol intake than males. Menthol administered both orally and systemically (intraperitoneal) increased oral nicotine consumption. Adolescent female mice had a higher nicotine intake at lower menthol concentrations compared to their adult counterparts. While α7 nAChR wild type mice consumed more mentholated nicotine solution than nicotine only solution, this effect was abolished in KO mice. Effects of menthol are concentration-, sex-, age-, and α7 nAChR-dependent. Oral and intraperitoneal menthol increases nicotine intake, suggesting that sensory, peripheral, and/or central mechanisms are involved in effects of menthol on oral nicotine consumption.
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Affiliation(s)
- Deniz Bagdas
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, USA; Yale Tobacco Center of Regulatory Science, Yale University, New Haven, CT, USA; The Center for the Study for Tobacco Products, Virginia Commonwealth University, Richmond, VA, USA.
| | - Asti Jackson
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, USA; Yale Tobacco Center of Regulatory Science, Yale University, New Haven, CT, USA
| | - Moriah Carper
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Rita Yu-Tzu Chen
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Lois S Akinola
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA; The Center for the Study for Tobacco Products, Virginia Commonwealth University, Richmond, VA, USA
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Green Apple e-Cigarette Flavorant Farnesene Triggers Reward-Related Behavior by Promoting High-Sensitivity nAChRs in the Ventral Tegmental Area. eNeuro 2020; 7:ENEURO.0172-20.2020. [PMID: 32747456 PMCID: PMC7433896 DOI: 10.1523/eneuro.0172-20.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/04/2020] [Accepted: 06/11/2020] [Indexed: 11/21/2022] Open
Abstract
While combustible cigarette smoking has declined, the use of electronic nicotine delivery systems (ENDS) has increased. ENDS are popular among adolescents, and chemical flavorants are an increasing concern because of the growing use of zero-nicotine flavored e-liquids. Despite this, little is known regarding the effects of ENDS flavorants on vaping-related behavior. Following previous studies demonstrating the green apple flavorant, farnesol, enhances nicotine reward and exhibits rewarding properties without nicotine, this work focuses on the green apple flavorant, farnesene, for its impact on vaping-related behaviors. Using adult C57BL/6J mice, genetically modified to contain fluorescent nicotinic acetylcholine receptors (nAChRs), and farnesene doses of 0.1, 1.0, and 10 mg/kg, we observed farnesene-alone produces reward-related behavior in both male and female mice. We then performed whole-cell patch-clamp electrophysiology and observed farnesene-induced inward currents in ventral tegmental area (VTA) putative dopamine (pDA) neurons that were blocked by the nAChR antagonist, DhβE. While the amplitudes of farnesene-induced currents are ∼30% of nicotine's efficacy, this indicates the potential for some ENDS flavorants to stimulate nAChR function. Additionally, farnesene enhances nicotine's potency for activating nAChRs on VTA dopamine neurons. This may be because of changes in nAChR stoichiometry as our data suggest a shift toward high-sensitivity α4β2 nAChRs. Consequently, these data show that the green apple flavorant, farnesene, causes reward-related behavior without nicotine through changes in nAChR stoichiometry that results in an enhanced effect of nicotine on VTA dopamine neurons. These results demonstrate the importance of future investigations into ENDS flavorants and their effects on vaping-related behaviors.
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Kopa PN, Pawliczak R. Menthol additives to tobacco products. Reasons for withdrawing mentholated cigarettes in European Union on 20th may 2020 according to tobacco products directive (2014/40/EU). Toxicol Mech Methods 2020; 30:555-561. [PMID: 32746758 DOI: 10.1080/15376516.2020.1805662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Menthol, which is a natural cyclic monoterpene alcohol with a minty smell, is one of the main constituents of essential oils that naturally occur in some aromatic plants, such as Mentha × piperita L. This natural compound shows many biological properties, such as anesthetic, analgesic, antibacterial and antifungal, immunomodulating, and skin penetration-enhancing. It is added to a variety of goods, such as food, oral-care products, OTC products, cosmetics, and tobacco products. Menthol is not just a simple flavoring agent, especially when it comes to tobacco products. Its ability to 'mask' the negative effects of nicotine and its additional positive sensory effects makes it the most common additive in such products. For the customers, mentholated tobacco products may be mistakenly perceived as less harmful for health, which may increase their consumption. However, as the evidence shows, menthol cigarettes are no safer than conventional cigarettes and may lead to more frequent disease exacerbation during prolonged exposure to smoke from such products. In addition, because of its complex interactions with nicotine, menthol may affect smoking behavior and may increase addiction to nicotine. For those reasons, the European Union banned flavored cigarettes (whose sale size reached more than 3% of the total tobacco product market) by implementing the Tobacco Products Directive (2014/40/EU) on 20th May 2020. While the menthol ban was based on health concerns, the ultimate effect on consumers, regarding potential quitting, is yet to be determined.
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Affiliation(s)
- Paulina Natalia Kopa
- Faculty of Medicine, Department of Immunopathology, Division of Biomedical Science, Medical University of Lodz, Lodz, Poland
| | - Rafał Pawliczak
- Faculty of Medicine, Department of Immunopathology, Division of Biomedical Science, Medical University of Lodz, Lodz, Poland
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Huynh YW, Raimondi A, Finkner A, Kuck JD, Selleck C, Bevins RA. Menthol blunts the interoceptive discriminative stimulus effects of nicotine in female but not male rats. Psychopharmacology (Berl) 2020; 237:2395-2404. [PMID: 32448943 PMCID: PMC7354904 DOI: 10.1007/s00213-020-05542-8] [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: 12/23/2019] [Accepted: 04/27/2020] [Indexed: 01/29/2023]
Abstract
RATIONALE Menthol is a widely used tobacco constituent that has shown to enhance nicotine's reinforcing effects. OBJECTIVE To determine whether injected menthol also alters nicotine's stimulus effects, we used a drug discrimination task. METHODS A total of 57 adult Sprague-Dawley rats (28M, 29F) received 20 positive and 20 negative days (intermixed) of discrimination training. On positive days, rats received a group-specific menthol and nicotine injection (VEH + 0.1 NIC, 1 M + 0.1 NIC, 5 M + 0.1 NIC, VEH + 0.4 NIC, 1 M + 0.4 NIC, 5 M + 0.4 NIC; mg/kg) before eight 15-s cue light presentations (conditioned stimulus (CS)), each followed by 4-s sucrose access. On negative days, all rats were injected with vehicle and saline before eight non-reinforced CS presentations. Next, rats underwent generalization testing with 30 dose combinations of menthol and nicotine. The change in drug-mediated anticipatory goal tracking during the CS was calculated as a difference score (CS minus pre-CS responding). RESULTS All groups readily acquired drug discrimination. However, difference scores for the 5M + 0.1 NIC group were lower for females. Additionally, females had lower scores for 0.05, 0.1, and 0.4 mg/kg nicotine generalization tests. The lowest nicotine dose discriminable from saline was 0.05 mg/kg for females but 0.025 mg/kg for males. Co-administration with 5 or 10 mg/kg menthol weakened discrimination performance between 0.1 and 0.4 mg/kg and between 0.1 and 0.05 mg/kg nicotine for 0.1 mg/kg nicotine training groups. CONCLUSIONS Female rats that were trained with 0.1 mg/kg nicotine were more sensitive to menthol's modulatory effects on nicotine's stimulus effects. This highlights the importance of taking sex and training dose into account when evaluating the interoceptive stimulus effects of nicotine and menthol.
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Affiliation(s)
- Y Wendy Huynh
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA
| | - Anthony Raimondi
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA
| | - Andrew Finkner
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA
| | - Jordan D Kuck
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA
| | - Carly Selleck
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA
| | - Rick A Bevins
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588-0308, USA.
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Patten T, De Biasi M. History repeats itself: Role of characterizing flavors on nicotine use and abuse. Neuropharmacology 2020; 177:108162. [PMID: 32497589 DOI: 10.1016/j.neuropharm.2020.108162] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 12/13/2022]
Abstract
The popularity of e-cigarettes has skyrocketed in recent years, and most vapers use flavored e-cigarette products. Consumption of flavored e-cigarettes exceeds that of combustible cigarettes and other tobacco products among adolescents, who are particularly vulnerable to becoming nicotine dependent. Flavorings have been used by the tobacco industry since the 17th century, but the use of flavors by the e-cigarette industry to create products with "characterizing" flavors (i.e. flavors other than tobacco or menthol) has sparked a public health debate. This review addresses the possibility that characterizing flavors make nicotine more appealing, rewarding and addictive. It also discusses ways in which preclinical and clinical studies could improve our understanding of the mechanisms by which flavors may alter nicotine reward and reinforcement. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Theresa Patten
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Mariella De Biasi
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
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Comparison of the Relative Abuse Liability of Electronic Cigarette Aerosol Extracts and Nicotine Alone in Adolescent Rats: A Behavioral Economic Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17030860. [PMID: 32019080 PMCID: PMC7037300 DOI: 10.3390/ijerph17030860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 12/02/2022]
Abstract
Background: Characterizing the determinants of the abuse liability of electronic cigarettes (ECs) in adolescents is needed to inform product regulation by the United States Food and Drug Administration (FDA). We recently reported that Vuse Menthol EC aerosol extract containing nicotine and a range of non-nicotine constituents (e.g., menthol, propylene glycol) had reduced aversive effects compared to nicotine alone in adolescent rats, whereas Aroma E-Juice EC aerosol extract did not. The current study used a behavioral economic approach to compare the relative abuse liability of these EC extracts and nicotine alone in an i.v. self-administration (SA) model in adolescents. Methods: Adolescents were tested for the SA of EC extracts prepared using an ethanol (ETOH) solvent or nicotine and saline, with and without 4% ETOH (i.e., the same concentration in the EC extracts) in 23 h/day sessions. Results. Although acquisition of SA was faster for nicotine + ETOH compared to all other formulations, the elasticity of demand for all nicotine-containing formulations was similar. Conclusions: EC aerosol extracts did not have greater abuse liability than nicotine alone in adolescents. These data suggest that nicotine may be the primary determinant of the abuse liability of these ECs in youth, at least in terms of the primary reinforcing effects of ECs mediated within the central nervous system.
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Leventhal A, Cho J, Barrington-Trimis J, Pang R, Schiff S, Kirkpatrick M. Sensory attributes of e-cigarette flavours and nicotine as mediators of interproduct differences in appeal among young adults. Tob Control 2019; 29:679-686. [PMID: 31852818 DOI: 10.1136/tobaccocontrol-2019-055172] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 10/13/2019] [Accepted: 10/31/2019] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To estimate the extent to which specific sensory attributes, for example, smoothness, mediate differences in electronic cigarette (e-cigarette) appeal between products in non-tobacco versus tobacco flavours and varying nicotine content in young adults. METHOD E-cigarette users (n=100; aged 18-34 years) administered standardised two-puff e-cigarette doses of different products varying in a flavour (fruit, menthol, tobacco) × nicotine (nicotine-containing (6 mg/mL freebase), nicotine-free) within-subject design. Participants rated sensory attributes (sweetness, bitterness, smoothness and harshness) and appeal on 100-unit visual analogue scales after administering each product. Sensory ratings were tested as simultaneous mediators of flavour, nicotine and flavour × nicotine effects on appeal. RESULTS Appeal preferences for fruit versus tobacco flavours were mediated by sweetness-enhancing (βindirect=0.092), smoothness-enhancing (βindirect=0.045) and bitterness-reducing (βindirect=0.072) effects of fruit flavours. Appeal preferences for menthol versus tobacco flavours were mediated by menthol's smoothness-enhancing (βindirect=0.039) and bitterness-reducing (βindirect=0.034) effects. Lower appeal of nicotine-containing versus nicotine-free products was mediated by nicotine's sweetness-reducing (βindirect=-0.036), smoothness-reducing (βindirect=-0.156) and bitterness-increasing (βindirect=0.045) effects. Flavour × nicotine interaction effects on appeal were explained by menthol-related suppression of nicotine's bitterness-enhancing and sweetness-reducing mediation pathways and fruit-related suppression of nicotine's bitterness-enhancing mediation pathway. Harshness did not mediate appeal after adjusting for other sensory attributes. CONCLUSION Bitterness and smoothness may be cross-cutting mediators of interproduct variation in the effects of types of non-tobacco flavours and nicotine on e-cigarette appeal in young adults. Sweetness may also mediate appeal-enhancing effects of fruit and appeal-reducing effects of nicotine. Non-tobacco flavours may suppress appeal-reducing effects of nicotine in e-cigarettes through attenuation of nicotine's aversive taste attributes.
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Affiliation(s)
- Adam Leventhal
- Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Junhan Cho
- Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Jessica Barrington-Trimis
- Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Raina Pang
- Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Sara Schiff
- Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Matthew Kirkpatrick
- Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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The TRPA1 Ion Channel Contributes to Sensory-Guided Avoidance of Menthol in Mice. eNeuro 2019; 6:ENEURO.0304-19.2019. [PMID: 31624176 PMCID: PMC6825956 DOI: 10.1523/eneuro.0304-19.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/05/2019] [Accepted: 10/14/2019] [Indexed: 01/08/2023] Open
Abstract
The flavoring agent menthol elicits complex orosensory and behavioral effects including perceived cooling at low concentrations and irritation and ingestive avoidance at higher intensities. Oral menthol engages the cold-activated transient receptor potential (TRP) ion channel TRP melastatin 8 (TRPM8) on trigeminal fibers, although its aversive feature was discussed to involve activation of TRP ankyrin 1 (TRPA1) associated with nociceptive processing. Here, we studied the roles of TRPM8 and TRPA1 in orosensory responding to menthol by subjecting mice gene deficient for either channel to brief-access exposure tests, which measure immediate licking responses to fluid stimuli to capture sensory/tongue control of behavior. Stimuli included aqueous concentration series of (−)-menthol [0 (water), 0.3, 0.5, 0.7, 1.0, 1.5, and 2.3 mM] and the aversive bitter taste stimulus quinine-HCl (0, 0.01, 0.03, 0.1, 0.3, 1, and 3 mM). Concentration-response data were generated from daily brief-access tests conducted in lickometers, which recorded the number of licks water-restricted mice emitted to a randomly selected stimulus concentration over a block of several 10-s stimulus presentations. Wild-type mice showed aversive orosensory responses to menthol above 0.7 mM. Oral aversion to menthol was reduced in mice deficient for TRPA1 but not TRPM8. Oral aversion to quinine was similar between TRPA1 mutant and control mice but stronger than avoidance of menthol. This implied menthol avoidance under the present conditions represented a moderate form of oral aversion. These data reveal TRPA1 contributes to the oral sensory valence of menthol and have implications for how input from TRPA1 and TRPM8 shapes somatosensory-guided behaviors.
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Mulcahy MJ, Huard SM, Paulo JA, Wang JH, McKinney S, Henderson BJ, Lester HA. Brain Region-Specific nAChR and Associated Protein Abundance Alterations Following Chronic Nicotine and/or Menthol Exposure. J Proteome Res 2019; 19:36-48. [PMID: 31657575 DOI: 10.1021/acs.jproteome.9b00286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The identification of biomarkers that are altered following nicotine/tobacco exposure can facilitate the investigation of tobacco-related diseases. Nicotinic acetylcholine receptors (nAChRs) are pentameric cation channels expressed in the mammalian central and peripheral nervous systems and the neuromuscular junction. Neuronal nAChR subunits (11) have been identified in mammals (α2-7, α9-10, β2-4). We examined changes in β2 nAChR subunit protein levels after chronic nicotine, (±)-menthol, or nicotine co-administered with (±)-menthol in nine murine brain regions. Our investigation of β2 nAChR subunit level changes identified the hypothalamus as a novel region of interest for menthol exposure that demonstrated increased β2 nAChR levels after (±)-menthol plus nicotine exposure compared to nicotine exposure alone. Using mass spectrometry, we further characterized changes in membrane protein abundance profiles in the hypothalamus to identify potential biomarkers of (±)-menthol plus nicotine exposure and proteins that may contribute to the elevated β2 nAChR subunit levels. In the hypothalamus, 272 membrane proteins were identified with altered abundances after chronic nicotine plus menthol exposure with respect to chronic nicotine exposure without menthol. A comprehensive investigation of changes in nAChR and non-nAChR protein expression resulting from (±)-menthol plus nicotine in the brain may establish biomarkers to better understand the effects of these drugs on addiction and addiction-related diseases.
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Affiliation(s)
- Matthew J Mulcahy
- Division of Biology and Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125-2900 , United States
| | - Stephanie M Huard
- Division of Biology and Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125-2900 , United States
| | - Joao A Paulo
- Department of Cell Biology , Harvard Medical School , 240 Longwood Avenue , Boston , Massachusetts 02115 , United States
| | - Jonathan H Wang
- Division of Biology and Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125-2900 , United States
| | - Sheri McKinney
- Division of Biology and Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125-2900 , United States
| | - Brandon J Henderson
- Division of Biology and Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125-2900 , United States.,Department of Biomedical Sciences , Joan C. Edwards School of Medicine, Marshall University , Huntington , West Virginia 25701 , United States
| | - Henry A Lester
- Division of Biology and Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125-2900 , United States
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Krishnan-Sarin S, O’Malley SS. The science of flavour in tobacco products. WORLD HEALTH ORGANIZATION TECHNICAL REPORT SERIES 2019; 1015:125-142. [PMID: 36743396 PMCID: PMC9896977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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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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35
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Avelar AJ, Akers AT, Baumgard ZJ, Cooper SY, Casinelli GP, Henderson BJ. Why flavored vape products may be attractive: Green apple tobacco flavor elicits reward-related behavior, upregulates nAChRs on VTA dopamine neurons, and alters midbrain dopamine and GABA neuron function. Neuropharmacology 2019; 158:107729. [PMID: 31369741 DOI: 10.1016/j.neuropharm.2019.107729] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 07/22/2019] [Accepted: 07/28/2019] [Indexed: 01/15/2023]
Abstract
While nicotine is the primary addictive component in tobacco products, additional flavors have become a concern with the growing popularity of electronic nicotine delivery systems (ENDS). For this reason, we have begun to investigate popular tobacco and ENDS flavors. Here, we examined farnesol, a chemical flavorant used in green apple and fruit flavors in ENDS e-liquids, for its ability to produce reward-related behavior. Using male and female 3-6 month old C57BL/6 J mice and farnesol doses of 0.1, 1, and 10 mg/kg we identified a sex-dependent effect in a conditioned place preference assay: farnesol-alone produces reward-related behavior in only male mice. Despite this sex-dependent effect, 1.0 mg/kg farnesol enhances locomotor activity in both male and female mice. To understand farnesol's effect on reward-related behavior, we used whole-cell patch-clamp electrophysiology and confocal microscopy to investigate changes in putative dopamine and GABA neurons. For these approaches, we utilized genetically modified mice that contain fluorescent nicotinic acetylcholine receptors (nAChRs). Our electrophysiological assays with male mice revealed that farnesol treatment increases ventral tegmental area (VTA) dopamine neuron firing frequency and this may be due to a decrease in inhibitory tone from GABA neurons. Our microscopy assays revealed that farnesol treatment produces a significant upregulation of α6* nAChRs in male mice but not female mice. This was supported by an observed increase in α6* nAChR function in additional electrophysiology assays. These data provide evidence that popular tobacco flavorants may alter smoking-related behavior and promote the need to examine additional ENDS flavors.
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Affiliation(s)
- Alicia J Avelar
- Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV, USA
| | - Austin T Akers
- Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV, USA
| | - Zachary J Baumgard
- Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV, USA
| | - Skylar Y Cooper
- Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV, USA
| | - Gabriella P Casinelli
- Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV, USA
| | - Brandon J Henderson
- Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV, USA.
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36
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Meehan-Atrash J, Duell AK, McWhirter KJ, Luo W, Peyton DH, Strongin RM. Free-Base Nicotine Is Nearly Absent in Aerosol from IQOS Heat-Not-Burn Devices, As Determined by 1H NMR Spectroscopy. Chem Res Toxicol 2019; 32:974-976. [PMID: 31088073 PMCID: PMC9888077 DOI: 10.1021/acs.chemrestox.9b00076] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Heat-not-burn products, eg, I quit ordinary smoking (IQOS), are becoming popular alternative tobacco products. The nicotine aerosol protonation state has addiction implications due to differences in absorption kinetics and harshness. Nicotine free-base fraction (αfb) ranges from 0 to 1. Herein, we report αfb for IQOS aerosols by exchange-averaged 1H NMR chemical shifts of the nicotine methyl protons in bulk aerosol and verified by headspace-solid phase microextraction-gas chromatography-mass spectrometry. The αfb ≈ 0 for products tested; likely a result of proton transfer from acetic acid and/or other additives in the largely aqueous aerosol. Others reported higher αfb for these products, however, their methods were subject to error due to solvent perturbation.
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Affiliation(s)
- Jiries Meehan-Atrash
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Anna K Duell
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Kevin J. McWhirter
- Department of Civil and Environmental Engineering, Portland State University, Portland, Oregon 97207-0751, United States
| | - Wentai Luo
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States,Department of Civil and Environmental Engineering, Portland State University, Portland, Oregon 97207-0751, United States
| | - David H. Peyton
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Robert M. Strongin
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States,Corresponding Author:
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37
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Nesil T, Narmeen S, Bakhti-Suroosh A, Lynch WJ. Effect of menthol on nicotine intake and relapse vulnerability in a rat model of concurrent intravenous menthol/nicotine self-administration. Psychopharmacology (Berl) 2019; 236:1219-1232. [PMID: 30483833 PMCID: PMC6536373 DOI: 10.1007/s00213-018-5128-9] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 11/19/2018] [Indexed: 11/30/2022]
Abstract
RATIONALE Epidemiological data suggest that menthol may increase vulnerability to cigarette/nicotine use and relapse. While menthol's sensory properties are often attributed as the underlying cause of the enhanced vulnerability, an alternative possibility is that they are mediated via pharmacological interactions with nicotine. OBJECTIVE This study addressed the possibility that menthol enhances nicotine intake and relapse vulnerability via pharmacological interactions with nicotine using a concurrent intravenous menthol/nicotine self-administration procedure. METHODS Following acquisition, adolescent rats were given 23-h/day access to nicotine (0.01 mg/kg/infusion), nicotine plus menthol (0.16, 0.32, or 0.64 mg/kg/infusion), or menthol alone (0.16, 0.32, 0.64 mg/kg/infusion) for a total of 10 days. Nicotine-seeking was assessed using an extinction/cue-induced reinstatement procedure following 10 days of forced abstinence. We also assessed the effect of menthol (0.32 mg/kg/infusion) on progressive ratio responding for nicotine (0.01 mg/kg/infusion). RESULTS Menthol decreased PR responding for nicotine but did not affect self-administration under extended access conditions. The low dose of menthol tended to decrease subsequent extinction responding, and was not different from menthol alone, whereas the high dose decreased reinstatement responding. Although not significant, the highest levels of extinction responding were observed in a minority of rats in the moderate and high menthol-nicotine groups; rats in these groups also took longer to extinguish. CONCLUSIONS Taken together, these results demonstrate that pharmacological interactions of menthol with nicotine reduce, rather than increase, nicotine's reinforcing effects and some measures of relapse vulnerability. Importantly, however, moderate and high menthol doses may increase some aspects of relapse vulnerability in a minority of individuals.
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MESH Headings
- Animals
- Behavior, Addictive/chemically induced
- Behavior, Addictive/psychology
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Conditioning, Operant/drug effects
- Conditioning, Operant/physiology
- Extinction, Psychological/drug effects
- Extinction, Psychological/physiology
- Infusions, Intravenous
- Male
- Menthol/administration & dosage
- Menthol/toxicity
- Nicotine/administration & dosage
- Nicotine/toxicity
- Nicotinic Agonists/administration & dosage
- Nicotinic Agonists/toxicity
- Rats
- Rats, Sprague-Dawley
- Recurrence
- Reinforcement, Psychology
- Self Administration
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Affiliation(s)
- Tanseli Nesil
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, 22902, USA
| | - Syeda Narmeen
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, 22902, USA
| | - Anousheh Bakhti-Suroosh
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, 22902, USA
| | - Wendy J Lynch
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, 22902, USA.
- Department of Psychiatry and Neurobehavioral Sciences, PO Box 801402, Charlottesville, VA, 22904, USA.
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Mead EL, Duffy V, Oncken C, Litt MD. E-cigarette palatability in smokers as a function of flavorings, nicotine content and propylthiouracil (PROP) taster phenotype. Addict Behav 2019; 91:37-44. [PMID: 30470456 PMCID: PMC6358501 DOI: 10.1016/j.addbeh.2018.11.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 10/01/2018] [Accepted: 11/13/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND The popularity of E-cigarettes is due in part to their flavorings. The purpose of this study was to determine the effect on smokers' sensory perceptions and liking of various e-cigarette flavorings, and the degree to which those perceptions are influenced by nicotine level, sex, and PROP bitter taster phenotype. METHODS We recruited 132 non-treatment-seeking, daily cigarette smokers. In repeated trials in one laboratory session participants vaped the Joyetech eGo-C e-cigarette with each of the following flavorings (in random order): unflavored, tobacco, cherry, chocolate, and menthol. Participants vaped the e-juice first without nicotine and then with high nicotine (18 mg/ml), and provided sensory (bitterness/sourness, irritation, sweetness) and liking ratings. Perceived intensity of 6-n-propylthiouracil (PROP) was used to classify the participants as non-tasters (n = 28), medium-tasters (n = 74), or supertasters (n = 28). Mixed-effects linear models and generalized estimating equations were used to evaluate ratings as a function of flavor interacting with nicotine content, sex and taster phenotype, adjusting for age, race/ethnicity, menthol use, and nicotine dependence. RESULTS Regardless of nicotine level, cherry (β = 1.76, p < .001) and chocolate (β = 0.69, p < .001) were rated as sweeter, but were not better liked, than unflavored e-juice. Menthol elicited the highest liking rating, especially for women (β = 12.23, p < .05) and supertasters (β = 20.52, p < .05). Regardless of flavor, high nicotine was rated as more irritating (OR = 1.43, 95% CI = 1.02-2.01) than the no-nicotine e-juice. Irritation (β = -13.65, p < .001), bitterness/sourness (β = -11.38, p < .001), and sweetness (β = 4.79, p < .001) were associated with liking. CONCLUSION Menthol may enhance e-cigarette palatability for some smokers, which may increase e-cigarette utility in smoking cessation.
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Affiliation(s)
- Erin L Mead
- Department of Medicine, MC3229, University of Connecticut School of Medicine, Farmington, CT 06030, USA.
| | - Valerie Duffy
- Department of Allied Health Science, College of Agricultural, Health & Natural Resources, University of Connecticut, Storrs, CT 06269, USA.
| | - Cheryl Oncken
- Department of Medicine, MC3229, University of Connecticut School of Medicine, Farmington, CT 06030, USA.
| | - Mark D Litt
- Division of Behavioral Sciences and Community Health, MC3910, UConn Health, Farmington, CT 06030, USA.
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39
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Leijon SCM, Neves AF, Breza JM, Simon SA, Chaudhari N, Roper SD. Oral thermosensing by murine trigeminal neurons: modulation by capsaicin, menthol and mustard oil. J Physiol 2019; 597:2045-2061. [PMID: 30656684 DOI: 10.1113/jp277385] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/14/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Orosensory thermal trigeminal afferent neurons respond to cool, warm, and nociceptive hot temperatures with the majority activated in the cool range. Many of these thermosensitive trigeminal orosensory afferent neurons also respond to capsaicin, menthol, and/or mustard oil (allyl isothiocyanate) at concentrations found in foods and spices. There is significant but incomplete overlap between afferent trigeminal neurons that respond to oral thermal stimulation and to the above chemesthetic compounds. Capsaicin sensitizes warm trigeminal thermoreceptors and orosensory nociceptors; menthol attenuates cool thermoresponses. ABSTRACT When consumed with foods, mint, mustard, and chili peppers generate pronounced oral thermosensations. Here we recorded responses in mouse trigeminal ganglion neurons to investigate interactions between thermal sensing and the active ingredients of these plants - menthol, allyl isothiocyanate (AITC), and capsaicin, respectively - at concentrations found in foods and commercial hygiene products. We carried out in vivo confocal calcium imaging of trigeminal ganglia in which neurons express GCaMP3 or GCAMP6s and recorded their responses to oral stimulation with thermal and the above chemesthetic stimuli. In the V3 (oral sensory) region of the ganglion, thermoreceptive neurons accounted for ∼10% of imaged neurons. We categorized them into three distinct classes: cool-responsive and warm-responsive thermosensors, and nociceptors (responsive only to temperatures ≥43-45 °C). Menthol, AITC, and capsaicin also elicited robust calcium responses that differed markedly in their latencies and durations. Most of the neurons that responded to these chemesthetic stimuli were also thermosensitive. Capsaicin and AITC increased the numbers of warm-responding neurons and shifted the nociceptor threshold to lower temperatures. Menthol attenuated the responses in all classes of thermoreceptors. Our data show that while individual neurons may respond to a narrow temperature range (or even bimodally), taken collectively, the population is able to report on graded changes of temperature. Our findings also substantiate an explanation for the thermal sensations experienced when one consumes pungent spices or mint.
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Affiliation(s)
- Sara C M Leijon
- Department of Physiology & Biophysics, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Amanda F Neves
- Department of Physiology & Biophysics, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Joseph M Breza
- Department of Psychology, Program in Neuroscience, 341J Science Complex, Eastern Michigan University, Ypsilanti, MI, 48197, USA
| | - Sidney A Simon
- Department of Neurobiology, Duke University, Durham, NC, USA
| | - Nirupa Chaudhari
- Department of Physiology & Biophysics, Miller School of Medicine, University of Miami, Miami, FL, USA.,Department of Otolaryngology, Miller School of Medicine, University of Miami, and Program in Neuroscience, University of Miami, Miami, FL, USA
| | - Stephen D Roper
- Department of Physiology & Biophysics, Miller School of Medicine, University of Miami, Miami, FL, USA.,Department of Otolaryngology, Miller School of Medicine, University of Miami, and Program in Neuroscience, University of Miami, Miami, FL, USA
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40
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Henderson BJ, Grant S, Chu BW, Shahoei R, Huard SM, Saladi SSM, Tajkhorshid E, Dougherty DA, Lester HA. Menthol Stereoisomers Exhibit Different Effects on α4β2 nAChR Upregulation and Dopamine Neuron Spontaneous Firing. eNeuro 2018; 5:ENEURO.0465-18.2018. [PMID: 30627659 PMCID: PMC6325563 DOI: 10.1523/eneuro.0465-18.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 12/08/2018] [Indexed: 11/21/2022] Open
Abstract
Menthol contributes to poor cessation rates among smokers, in part because menthol enhances nicotine reward and reinforcement. Mentholated tobacco products contain (-)-menthol and (+)-menthol, in varying proportions. We examined these two menthol stereoisomers for their ability to upregulate α4β2 nAChRs and to alter dopamine neuron firing frequency using long-term, low-dose (≤500 nm) exposure that is pharmacologically relevant to smoking. We found that (-)-menthol upregulates α4β2 nAChRs while (+)-menthol does not. We also found that (-)-menthol decreases dopamine neuron baseline firing and dopamine neuron excitability, while (+)-menthol exhibits no effect. We then examined both stereoisomers for their ability to inhibit α4β2 nAChR function at higher concentrations (>10 µm) using the Xenopus oocyte expression system. To probe for the potential binding site of menthol, we conducted flooding simulations and site-directed mutagenesis. We found that menthol likely binds to the 9´ position on the TM2 (transmembrane M2) helix. We found that menthol inhibition is dependent on the end-to-end distance of the side chain at the 9´ residue. Additionally, we have found that (-)-menthol is only modestly (∼25%) more potent than (+)-menthol at inhibiting wild-type α4β2 nAChRs and a series of L9´ mutant nAChRs. These data reveal that menthol exhibits a stereoselective effect on nAChRs and that the stereochemical effect is much greater for long-term, submicromolar exposure in mice than for acute, higher-level exposure. We hypothesize that of the two menthol stereoisomers, only (-)-menthol plays a role in enhancing nicotine reward through nAChRs on dopamine neurons.
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Affiliation(s)
- Brandon J. Henderson
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine at Marshall University, Huntington, West Virginia 25703
| | - Stephen Grant
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Betty W. Chu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Rezvan Shahoei
- Department of Physics, National Institutes of Health Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Stephanie M. Huard
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Shyam S. M. Saladi
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Emad Tajkhorshid
- Department of Biochemistry, National Institutes of Health Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Dennis A. Dougherty
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Henry A. Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
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Stanton CA, Villanti AC, Watson C, Delnevo CD. Flavoured tobacco products in the USA: synthesis of recent multidiscipline studies with implications for advancing tobacco regulatory science. Tob Control 2018; 25:ii1-ii3. [PMID: 27856996 DOI: 10.1136/tobaccocontrol-2016-053486] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 10/17/2016] [Indexed: 11/04/2022]
Affiliation(s)
- Cassandra A Stanton
- Westat Inc, Rockville, Maryland, USA.,Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, USA
| | - Andrea C Villanti
- Schroeder Institute for Tobacco Research and Policy Studies at Truth Initiative, Washington DC, USA
| | - Clifford Watson
- National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Cristine D Delnevo
- Center for Tobacco Studies, School of Public Health, Rutgers, the State University, New Brunswick, New Jersey, USA
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42
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Henderson BJ, Wall TR, Henley BM, Kim CH, McKinney S, Lester HA. Menthol Enhances Nicotine Reward-Related Behavior by Potentiating Nicotine-Induced Changes in nAChR Function, nAChR Upregulation, and DA Neuron Excitability. Neuropsychopharmacology 2017; 42:2285-2291. [PMID: 28401925 PMCID: PMC5645749 DOI: 10.1038/npp.2017.72] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/28/2017] [Accepted: 04/01/2017] [Indexed: 12/17/2022]
Abstract
Understanding why the quit rate among smokers of menthol cigarettes is lower than non-menthol smokers requires identifying the neurons that are altered by nicotine, menthol, and acetylcholine. Dopaminergic (DA) neurons in the ventral tegmental area (VTA) mediate the positive reinforcing effects of nicotine. Using mouse models, we show that menthol enhances nicotine-induced changes in nicotinic acetylcholine receptors (nAChRs) expressed on midbrain DA neurons. Menthol plus nicotine upregulates nAChR number and function on midbrain DA neurons more than nicotine alone. Menthol also enhances nicotine-induced changes in DA neuron excitability. In a conditioned place preference (CPP) assay, we observed that menthol plus nicotine produces greater reward-related behavior than nicotine alone. Our results connect changes in midbrain DA neurons to menthol-induced enhancements of nicotine reward-related behavior and may help explain how smokers of menthol cigarettes exhibit reduced cessation rates.
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Affiliation(s)
- Brandon J Henderson
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA,Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV, USA
| | - Teagan R Wall
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Beverley M Henley
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Charlene H Kim
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sheri McKinney
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Henry A Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA,Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard MC 156-29, Pasadena, CA 91125-2900, USA, Tel: +626 395 4946, Fax: +626 564 8709, E-mail:
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43
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Krishnan-Sarin S, Green BG, Kong G, Cavallo DA, Jatlow P, Gueorguieva R, Buta E, O’Malley SS. Studying the interactive effects of menthol and nicotine among youth: An examination using e-cigarettes. Drug Alcohol Depend 2017; 180:193-199. [PMID: 28915478 PMCID: PMC5659733 DOI: 10.1016/j.drugalcdep.2017.07.044] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/25/2017] [Accepted: 07/30/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Tobacco products containing menthol are widely used by youth. We used e-cigarettes to conduct an experimental evaluation of the independent and interactive effects of menthol and nicotine among youth. PROCEDURES Pilot chemosensory experiments with fourteen e-cigarette users identified low (barely perceptible, 0.5%) and high (similar to commercial e-liquid, 3.5%) menthol concentrations. Sixty e-cigarette users were randomized to a nicotine concentration (0mg/ml, 6mg/ml, 12mg/ml) and participated in 3 laboratory sessions. During each session, they received their assigned nicotine concentration, along with one of three menthol concentrations in random counterbalanced order across sessions (0, 0.5%, 3.5%), and participated in three fixed-dose, and an ad-lib, puffing period. Urinary menthol glucuronide and salivary nicotine levels validated menthol and nicotine exposure. We examined changes in e-cigarette liking/wanting and taste, coolness, stimulant effects, nicotine withdrawal and ad-lib use. RESULTS Overall, the high concentration of menthol (3.5%) significantly increased e-cigarette liking/wanting relative to no menthol (p<0.001); there was marginal evidence of nicotine* menthol interactions (p=0.06), with an increase in liking/wanting when 3.5% menthol was combined with 12mg/ml nicotine, but not 6mg/ml nicotine. Importantly, both 0.5% and 3.5% menthol concentrations significantly improved taste and increased coolness. We did not observe nicotine or menthol-related changes in stimulant effects, nicotine withdrawal symptoms or ad-lib use. CONCLUSIONS Menthol, even at very low doses, alters the appeal of e-cigarettes among youth. Further, menthol enhances positive rewarding effects of high nicotine-containing e-cigarettes among youth.
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Affiliation(s)
| | - Barry G. Green
- The John B. Pierce Laboratory and Department of Surgery, Yale University School of Medicine
| | - Grace Kong
- Department of Psychiatry, Yale University School of Medicine
| | - Dana A. Cavallo
- Department of Psychiatry, Yale University School of Medicine
| | - Peter Jatlow
- Department of Laboratory Medicine, Yale University School of Medicine
| | | | - Eugenia Buta
- Department of Biostatistics, Yale University School of Public Health
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Lallai V, Fowler CD. More Than Just Chillin': Interactive Effects of Menthol and Nicotine in Drug Reward. Neuropsychopharmacology 2017; 42:2283-2284. [PMID: 28553838 PMCID: PMC5645734 DOI: 10.1038/npp.2017.107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 05/03/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Valeria Lallai
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA
| | - Christie D Fowler
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA,Department of Neurobiology and Behavior, University of California Irvine, 1232 McGaugh Hall, Irvine, CA 92697, USA, Tel: +1 949 824 8363, Fax: +1 949 824 2447, E-mail:
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Evaluating oral flavorant effects on nicotine self-administration behavior and phasic dopamine signaling. Neuropharmacology 2017; 128:33-42. [PMID: 28943284 DOI: 10.1016/j.neuropharm.2017.09.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/31/2017] [Accepted: 09/19/2017] [Indexed: 12/26/2022]
Abstract
Understanding how tobacco product flavor additives, such as flavorants in electronic cigarettes, influence smoking behavior and addiction is critical for informing public health policy decisions regarding tobacco product regulation. Here, we developed a combined intraoral (i.o.) and intravenous (i.v.) self-administration paradigm in rats to determine how flavorants influence self-administration behavior. By combining i.o. flavorant delivery with fast scan cyclic voltammetry (FSCV) or i.v. nicotine self-administration in adult, male rats, we examined whether flavors alter phasic dopamine (DA) signaling and nicotine self-administration. Oral administration of 10% sucrose or 0.32% saccharin, but not 0.005% menthol, increased phasic DA release in the nucleus accumbens (NAc). Oral sucrose or saccharin, when combined with i.v. nicotine delivery, also led to increased self-administration behavior. Specifically, combined i.o. sucrose and i.v. nicotine decreased responding compared to sucrose alone, and increased responding compared to nicotine alone. In contrast, i.o. flavorants did not alter motivational breakpoint in a progressive ratio task. Oral menthol, which did not alter i.v. nicotine administration, reversed oral nicotine aversion (50 and 100 mg/L) in a two-bottle choice test. Here, we demonstrate that i.o. appetitive flavorants that increase phasic DA signaling also increase self-administration behavior when combined with i.v. nicotine delivery. Additionally, oral menthol effects were specific to oral nicotine, and were not observed with i.v. nicotine-mediated reinforcement. Together, these preclinical findings have important implications regarding menthol and sweet flavorant additive effects on tobacco product use and can be used to inform policy decisions on tobacco product flavorant regulation.
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Fait BW, Thompson DC, Mose TN, Jatlow P, Jordt SE, Picciotto MR, Mineur YS. Menthol disrupts nicotine's psychostimulant properties in an age and sex-dependent manner in C57BL/6J mice. Behav Brain Res 2017; 334:72-77. [PMID: 28743602 DOI: 10.1016/j.bbr.2017.07.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/28/2017] [Accepted: 07/18/2017] [Indexed: 11/26/2022]
Abstract
Menthol is a commonly used flavorant in tobacco and e-cigarettes, and could contribute to nicotine sensitivity. To understand how menthol could contribute to nicotine intake and addiction, it is important to determine whether specific mechanisms related to sex and age could underlie behavioral changes induced by menthol-laced nicotinic products. Using a validated paradigm of nicotine-dependent locomotor stimulation, adolescent and adult C57BL/6J mice of both sexes were exposed to nicotine, or nicotine laced with menthol, as their sole source of fluid, and psychostimulant effects were evaluated by recording home cage locomotor activity for ten days. Nicotine and cotinine blood levels were measured following exposure. Results show an interaction between treatment, age, and sex on liquid consumption, indicating that mice responded differently to menthol and nicotine based on their age and sex. Adult male mice greatly increased their nicotine intake when given menthol. In female mice of both age groups, menthol did not have this effect. Despite an increase in nicotine intake promoted by menthol, adult male mice showed a significant decrease in locomotion, suggesting that menthol blunted nicotine-induced psychostimulation. This behavioral response to menthol was not detected in adolescent mice of either sex. These data confirm that menthol is more than a flavorant, and can influence both nicotine intake and its psychostimulant effects. These results suggest that age- and sex-dependent mechanisms could underlie menthol's influence on nicotine intake and that studies including adolescent and adult menthol smokers of both sexes are warranted.
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Affiliation(s)
- Benjamin W Fait
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, 3rd Floor Research, New Haven, CT 06520, USA
| | - David C Thompson
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, 3rd Floor Research, New Haven, CT 06520, USA
| | - Tenna N Mose
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, 3rd Floor Research, New Haven, CT 06520, USA
| | - Peter Jatlow
- Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar Street, 4th floor, New Haven, CT 06520, USA
| | - Sven E Jordt
- Department of Cellular and Molecular Pharmacology University of California, San Francisco, CA 94143-2140, USA
| | - Marina R Picciotto
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, 3rd Floor Research, New Haven, CT 06520, USA
| | - Yann S Mineur
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, 3rd Floor Research, New Haven, CT 06520, USA.
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