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Chenoweth MJ, Peng AR, Zhu AZX, Cox LS, Nollen NL, Ahluwalia JS, Benowitz NL, Knight J, Swardfager W, Tyndale RF. Does sex alter the relationship between CYP2B6 variation, hydroxybupropion concentration and bupropion-aided smoking cessation in African Americans? A moderated mediation analysis. Addiction 2022; 117:1715-1724. [PMID: 34791718 DOI: 10.1111/add.15742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 10/28/2021] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND AIMS CYP2B6, a genetically variable enzyme, converts bupropion to its active metabolite hydroxybupropion. CYP2B6 activity and bupropion-aided cessation differ between women and men. The aim of this study was to determine whether genetically normal (versus reduced) CYP2B6 activity increases bupropion-aided cessation in African American smokers via higher hydroxybupropion concentration, and whether this differs by sex. DESIGN AND SETTING Secondary analysis of a smoking cessation clinical trial (NCT00666978). PARTICIPANTS/CASES African American light smokers (≤ 10 cigarettes/day). INTERVENTIONS Participants were treated with bupropion for 7 weeks. MEASUREMENTS Participants with detectable bupropion and/or hydroxybupropion concentrations were divided into normal (n = 64) and reduced (n = 109) CYP2B6 activity groups based on the presence of decreased-function CYP2B6*6 and CYP2B6*18 alleles. Biochemically verified smoking cessation was assessed at week 3, end of treatment (7 weeks) and follow-up (26 weeks). FINDINGS Normal (versus reduced) CYP2B6 activity was associated with increased cessation at week 7, which was mediated by higher hydroxybupropion concentration [odds ratio (OR) = 1.25, 95% confidence interval (CI) = 1.03, 1.78]; this mediation effect persisted at week 26 (OR = 1.23, 95% CI = 1.02, 1.70). The mediation effect was similar in women (n = 116; OR = 1.33, 95% CI = 1.01, 2.30) and men (n = 57; OR = 1.33, 95% CI = 0.92, 3.87). Moreover, sex did not appear to moderate the mediation effect, although this should be tested in a larger sample. CONCLUSIONS In African American light smokers with verified early bupropion use, genetically normal CYP2B6 activity appears to be indirectly associated with greater smoking cessation success in a relationship mediated by higher hydroxybupropion concentration. The mediating effect of higher hydroxybupropion concentration on smoking cessation persists beyond the active treatment phase and does not appear to differ by sex.
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Affiliation(s)
- Meghan J Chenoweth
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Annie R Peng
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Andy Z X Zhu
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Lisa Sanderson Cox
- Department of Population Health, University of Kansas School of Medicine, Kansas City, KS, USA
| | - Nikki L Nollen
- Department of Population Health, University of Kansas School of Medicine, Kansas City, KS, USA
| | - Jasjit S Ahluwalia
- Departments of Behavioral and Social Sciences and Medicine, Brown University, Providence, RI, USA
| | - Neal L Benowitz
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Jo Knight
- Data Science Institute, Lancaster University Medical School, Lancaster, UK.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Walter Swardfager
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.,Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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2
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Kharasch ED, Neiner A, Kraus K, Blood J, Stevens A, Miller JP, Lenze EJ. Stereoselective Steady-State Disposition and Bioequivalence of Brand and Generic Bupropion in Adults. Clin Pharmacol Ther 2020; 108:1036-1048. [PMID: 32386065 DOI: 10.1002/cpt.1888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022]
Abstract
The antidepressant bupropion is stereoselectively metabolized and metabolite enantiomers have differential pharmacologic effects, but steady-state enantiomeric disposition is unknown. Controversy persists about bupropion XL 300 mg generic equivalence to brand product, and whether generics might have different stereoselective disposition leading to enantiomeric non-bioequivalence and, thus, clinical nonequivalence. This preplanned follow-on analysis of a prospective, randomized, double-blinded, crossover study of brand and 3 generic bupropion XL 300 mg products measured steady-state enantiomeric plasma and urine parent bupropion and primary and secondary metabolite concentrations and evaluated bioequivalence and pharmacokinetics. Steady-state plasma and urine bupropion disposition was markedly stereoselective, with up to 40-fold differences in plasma concentrations of the active metabolite S,S-hydroxybupropion vs. R,R,-hydroxybupropion. Urine metabolite glucuronides were prominent, but glucuronidation was metabolite-specific and enantioselective. There were no differences between any generic and brand, or between generics, in plasma enantiomer concentrations of bupropion or the major metabolites. All generic products satisfied formal bioequivalence criteria (peak plasma concentration (Cmax ) and area under the plasma concentration-time curve over 24 hours (AUC0-24 )) using enantiomers for bupropion as well as for metabolites, and generics were comparable to each other, and were considered bioequivalent, based on enantiomeric analysis. Enantiomeric bioequivalence explains the previously observed therapeutic equivalence of bupropion generics and brand in treating major depression. These results have important implications for understanding the clinical therapeutic effects of bupropion based on complex and stereoselective metabolism.
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Affiliation(s)
- Evan D Kharasch
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Alicia Neiner
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Kristin Kraus
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Jane Blood
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Angela Stevens
- Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - J Philip Miller
- Division of Biostatistics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Eric J Lenze
- Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri, USA
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Wang PF, Neiner A, Kharasch ED. Stereoselective Bupropion Hydroxylation by Cytochrome P450 CYP2B6 and Cytochrome P450 Oxidoreductase Genetic Variants. Drug Metab Dispos 2020; 48:438-445. [PMID: 32238417 DOI: 10.1124/dmd.119.090407] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/10/2020] [Indexed: 12/12/2022] Open
Abstract
Bioactivation of the antidepressant and smoking cessation drug bupropion is catalyzed predominantly by CYP2B6. The metabolite hydroxybupropion derived from t-butylhydroxylation is considered to contribute to the antidepressant and smoking-cessation effects of the parent drug. Bupropion hydroxylation is the canonical in vitro and in vivo probe for CYP2B6 activity. P450 also requires obligate partnership with P450 oxidoreductase (POR). Human CYP2B6 and POR genes are highly polymorphic. Some CYP2B6 variants affect bupropion disposition. This investigation evaluated the influence of several human CYP2B6 and POR genetic variants on stereoselective bupropion metabolism, using an insect cell coexpression system containing CYP2B6, POR, and cytochrome b 5 Based on intrinsic clearances (Clints), relative activities for S,S-hydroxybupropion formation were in the order CYP2B6.4 > CYP2B6.1 > CYP2B6.17 > CYP2B6.5 > CYP2B6.6 ≈ CYP2B6.26 ≈ CYP2B6.19 > CYP2B6.7 > CYP2B6.9 > > CYP2B6.16 and CYP2B6.18; relative activities for R,R-hydroxybupropion formation were in the order CYP2B6.17 > CYP2B6.4 > CYP2B6.1 > CYP2B6.5 ≈ CYP2B6.19 ≈ CYP2B6.26 > CYP2B6.6 > CYP2B6.7 ≈ CYP2B6.9 > > CYP2B6.16 and CYP2B6.18. Bupropion hydroxylation was not influenced by POR variants. CYP2B6-catalyzed bupropion hydroxylation is stereoselective. Though Vmax and Km varied widely among CYP2B6 variants, stereoselectivity was preserved, reflected by similar Clint(S,S-hydroxybupropion)/Clint(R,R-hydroxybupropion) ratios (1.8-2.9), except CYP2B6.17, which was less enantioselective. Established concordance between human bupropion hydroxylation in vitro and in vivo, together with these new results, suggests additional CYP2B6 variants may influence human bupropion disposition. SIGNIFICANCE STATEMENT: Bupropion pharmacokinetics, metabolism, and clinical effects are affected by the CYP2B6*6 polymorphism. Other expressed CYP2B6 polymorphisms had diminished (*5, *6, *7, *9, *19, *26) or defective (*16, *18) in vitro bupropion hydroxylation. P450 oxidoreductase genetic variants had no effect on metabolism, suggesting no clinical consequence of this polymorphism. These CYP2B6 polymorphisms may portend diminished in vivo bupropion hydroxylation and predict additional clinically important variant alleles.
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Affiliation(s)
- Pan-Fen Wang
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
| | - Alicia Neiner
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
| | - Evan D Kharasch
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
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Shoaib M, Perkins KA. Preclinical and clinical research on the discriminative stimulus effects of nicotine. Neuropharmacology 2020; 170:108063. [PMID: 32220607 DOI: 10.1016/j.neuropharm.2020.108063] [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: 01/09/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 02/06/2023]
Abstract
Across species, nicotine can produce robust discriminative stimulus (DS) effects, as with other drugs of abuse, a feature that has been harnessed to advance our understanding on the neuropharmacological mechanisms of nicotine's actions. With the crucial role played by nicotine in supporting tobacco dependence, nicotine DS effects have presented an ideal platform to develop novel generation of smoking cessation compounds. Findings from preclinical strands of research have invigorated the field of human discrimination research to objectively assess nicotine's interoceptive stimulus effects. As such, translation studies provide proof of concept for nicotine DS research as a method to assess the subjective effects of nicotine per se, separate from non-nicotine stimuli involved in smoking. Recent clinical studies with low doses have demonstrated that perceiving nicotine's DS effects is necessary, yet not sufficient, for that dose to be reinforcing. These measures have been instrumental in developing novel strategies with regards to establishing threshold doses of nicotine contained in tobacco products, to then determine subthreshold doses that cannot be discriminated and, therefore, fail to maintain reinforcement. Findings from preclinical and clinical nicotine DS research could substantially inform public health policies aimed at regulating nicotine content of consumer products so that they minimize risks of dependency. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Mohammed Shoaib
- Institute of Neuroscience, The Medical School, Newcastle University, Newcastle, NE2 4HH, UK.
| | - Kenneth A Perkins
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Trigo JM, Le Foll B. Nicotine Self-Administration as Paradigm for Medication Discovery for Smoking Cessation: Recent Findings in Medications Targeting the Cholinergic System. Methods Mol Biol 2019; 2011:165-193. [PMID: 31273700 DOI: 10.1007/978-1-4939-9554-7_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Tobacco kills every year approximately six million people as a direct result of direct use, and it is still considered one of the most excruciating threats for human health worldwide. The low successful rates of the currently available pharmacotherapies to assist in quitting tobacco use suggest there is a need for more effective treatments.The intravenous self-administration (IVSA) paradigm is considered the gold standard to study voluntary drug intake in animal models, including nicotine. The IVSA paradigm has been used to identify key mechanisms involved in the addictive properties of nicotine in both rodents and nonhuman primates. In this chapter we describe how the IVSA paradigm has served to further investigate the role of nicotinic acetylcholine receptors (nAChRs) in the reinforcing properties of nicotine. Notably, this review will cover recent advances (i.e., research carried out during the past decade) using the IVSA paradigm, with a focus on the status of research on current smoking cessation medications (such as varenicline and bupropion) and of other nAChR ligands.The combination of the IVSA paradigm with pharmacological and genetic tools (e.g., knockout animals) has greatly contributed to our understanding of the role of specific subtype nAChRs in nicotine reinforcement processes. We also discuss some of the limitations of the IVSA paradigm so these can be taken into consideration when interpreting and designing new studies.
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Affiliation(s)
- Jose M Trigo
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Bernard Le Foll
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.
- Addictions Division, CAMH, Toronto, ON, Canada.
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Abstract
There is a plethora of amphetamine derivatives exerting stimulant, euphoric, anti-fatigue, and hallucinogenic effects; all structural properties allowing these effects are contained within the amphetamine structure. In the first part of this review, the interaction of amphetamine with the dopamine transporter (DAT), crucially involved in its behavioral effects, is covered, as well as the role of dopamine synthesis, the vesicular monoamine transporter VMAT2, and organic cation 3 transporter (OCT3). The second part deals with requirements in amphetamine's effect on the kinases PKC, CaMKII, and ERK, whereas the third part focuses on where we are in developing anti-amphetamine therapeutics. Thus, treatments are discussed that target DAT, VMAT2, PKC, CaMKII, and OCT3. As is generally true for the development of therapeutics for substance use disorder, there are multiple preclinically promising specific compounds against (meth)amphetamine, for which further development and clinical trials are badly needed.
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Affiliation(s)
- Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA.
| | - Margaret E Gnegy
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI, USA
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7
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Kharasch ED, Crafford A. Common Polymorphisms of CYP2B6 Influence Stereoselective Bupropion Disposition. Clin Pharmacol Ther 2018; 105:142-152. [PMID: 29756345 DOI: 10.1002/cpt.1116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022]
Abstract
Bupropion hydroxylation is a bioactivation and metabolic pathway, and the standard clinical CYP2B6 probe. This investigation determined the influence of CYP2B6 allelic variants on clinical concentrations and metabolism of bupropion enantiomers. Secondary objectives evaluated the influence of CYP2C19 and P450 oxidoreductase variants. Healthy volunteers in specific cohorts (CYP2B6*1/*1, CYP2B6*1/*6, CYP2B6*6/*6, and also CYP2B6*4 carriers) received single-dose oral bupropion. Plasma and urine bupropion and hydroxybupropion was quantified. Subjects were also genotyped for CYP2C19 and P450 oxidoreductase variants. Hydroxylation of both bupropion enantiomers, assessed by plasma hydroxybupropion/bupropion AUC ratios and urine hydroxybupropion formation clearances, was lower in CYP2B6*6/*6 but not CYP2B6*1/*6 compared with CYP2B6*1/*1 genotypes, and numerically greater in CYP2B6*4 carriers. CYP2C19 and P450 oxidoreductase variants did not influence bupropion enantiomers hydroxylation or plasma concentrations. The results show that clinical hydroxylation of both bupropion enantiomers was equivalently influenced by CYP2B6 allelic variation. CYP2B6 polymorphisms affect S-bupropion bioactivation, which may affect therapeutic outcomes.
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Affiliation(s)
- Evan D Kharasch
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, Missouri, USA.,Center for Clinical Pharmacology, St. Louis College of Pharmacy and Washington University in St. Louis, St. Louis, Missouri, USA
| | - Amanda Crafford
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA
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Shoaib M, Buhidma Y. Why are Antidepressant Drugs Effective Smoking Cessation Aids? Curr Neuropharmacol 2018; 16:426-437. [PMID: 28925882 PMCID: PMC6018185 DOI: 10.2174/1570159x15666170915142122] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 07/20/2017] [Accepted: 09/09/2017] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Before the advent of varenicline, antidepressant drugs were reported to exhibit better clinical efficacy than nicotine replacement therapy as smoking cessation aids. The most studied is bupropion, a clinically-effective antidepressant, the first to be marketed throughout Europe for smoking cessation. Since depression and tobacco smoking have a high incidence of cooccurrence, this would implicate an underlying link between these two conditions. If this correlation can be confirmed, then by treating one condition the related state would also be treated. OBJECTIVES This review article will evaluate the various theories relating to the use of antidepressant drugs as smoking cessation aids and the underlying mechanisms link tobacco smoking and depression to explain the action of antidepressants in smoking cessation. One plausible theory of self-medication which proposes that people take nicotine to treat their own depressive symptoms and the affective withdrawal symptoms seen with abstinence from the drug. If the depression can instead be treated with antidepressants, then they may stop smoking altogether. Another theory is that the neurobiological pathways underlying smoking and depression may be similar. By targeting the pathways of depression in the brain, antidepressants would also treat the pathways affected by smoking and ease nicotine cravings and withdrawal. The role of genetic variation predisposing an individual to depression and initiation of tobacco smoking has also been discussed as a potential link between the two conditions. Such variation could either occur within the neurobiological pathways involved in both disorders or it could lead to an individual being depressed and selfmedicating with nicotine.
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Affiliation(s)
- Mohammed Shoaib
- Institute of Neuroscience, Medical School, Newcastle University, Newcastle, UK
| | - Yazead Buhidma
- Institute of Neuroscience, Medical School, Newcastle University, Newcastle, UK
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9
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Pittenger ST, Barrett ST, Chou S, Bevins RA. The effects of varenicline on methamphetamine self-administration and drug-primed reinstatement in female rats. Behav Brain Res 2015; 300:150-9. [PMID: 26638833 DOI: 10.1016/j.bbr.2015.11.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/18/2015] [Accepted: 11/23/2015] [Indexed: 12/14/2022]
Abstract
While research has revealed heightened vulnerability to meth addiction in women, preclinical models rarely use female subjects when investigating meth seeking and relapse. The goal of the present study was to examine the effects of varenicline (Chantix(®)), a partial α4β2 and full α7 nicotinic acetylcholine receptor agonist, on meth self-administration and reinstatement in female rats. Sprague-Dawley rats were surgically implanted with an indwelling jugular catheter. Half of the rats were then trained to self-administer meth (0.056 mg/kg/infusion) on a variable ratio 3 schedule of reinforcement; the other half earned intravenous saline during daily, 2h sessions. When responding stabilized, varenicline (0.0, 0.3, 1.0, 3.0mg/kg) was tested to determine how it altered meth taking. Varenicline was probed on 4 test days; each test separated by 2 standard self-administration sessions to assure responding remained stable. Following this testing was 15 extinction sessions. Twenty-four hours after the last extinction session were four consecutive days of meth-primed reinstatement. The same 4 doses of varenicline were examined to determine how it altered reinstatement triggered by 0.3mg/kg meth (IP). Rats readily self-administered meth. The higher doses of varenicline did not affect meth-taking in a specific fashion as active lever pressing was also slightly reduced in rats that has access to saline in the self-administration phase. Female rats displayed robust meth-primed reinstatement. Notably, the lower doses of varenicline increased meth-primed reinstatement. This amplified susceptibility to reinstatement (i.e., relapse) may be an impediment for the use of varenicline as a therapeutic to treat meth use disorder.
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Affiliation(s)
- Steven T Pittenger
- University of Nebraska-Lincoln, Department of Psychology, 238 Burnett Hall, Lincoln, NE 68588-0308, USA
| | - Scott T Barrett
- University of Nebraska-Lincoln, Department of Psychology, 238 Burnett Hall, Lincoln, NE 68588-0308, USA
| | - Shinnyi Chou
- University of Nebraska-Lincoln, Department of Psychology, 238 Burnett Hall, Lincoln, NE 68588-0308, USA
| | - Rick A Bevins
- University of Nebraska-Lincoln, Department of Psychology, 238 Burnett Hall, Lincoln, NE 68588-0308, USA.
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