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Duratkar A, Patel R, Jain NS. Neuronal nicotinic acetylcholine receptor of the central amygdala modulates the ethanol-induced tolerance to anxiolysis and withdrawal-induced anxiety in male rats. Behav Pharmacol 2024; 35:132-146. [PMID: 38451025 DOI: 10.1097/fbp.0000000000000770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
The nicotine acetylcholinergic receptor (nAchR) in the central nucleus of the amygdala (CeA) is known to modulate anxiety traits as well as ethanol-induced behavioral effects. Therefore, the present study investigated the role of CeA nAChR in the tolerance to ethanol anxiolysis and withdrawal-induced anxiety-related effects in rats on elevated plus maze (EPM). To develop ethanol dependence, rats were given free access to an ethanol-containing liquid diet for 10 days. To assess the development of tolerance, separate groups of rats were challenged with ethanol (2 g/kg, i.p.) on days 1, 3, 5, 7 and 10 during the period of ethanol exposure, followed by an EPM assessment. Moreover, expression of ethanol withdrawal was induced after switching ethanol-dependent rats to a liquid diet on day 11, and withdrawal-induced anxiety-like behavior was noted at different post-withdrawal time points using the EPM test. The ethanol-dependent rats were pretreated with intra-CeA (i.CeA) (bilateral) injections of nicotine (0.25 µg/rat) or mecamylamine (MEC) (5 ng/rat) before the challenge dose of ethanol on subthreshold tolerance on the 5th day or on peak tolerance day, that is, 7th or 10th, and before assessment of postwithdrawal anxiety on the 11th day on EPM. Bilateral i.CeA preadministration of nicotine before the challenge dose of ethanol on days 5, 7 and 10 exhibited enhanced tolerance, while injection of MEC, completely mitigated the tolerance to the ethanol-induced antianxiety effect. On the other hand, ethanol-withdrawn rats pretreated i.CeA with nicotine exacerbated while pretreatment with MEC, alleviated the ethanol withdrawal-induced anxiety on all time points. Thus, the present investigation indicates that stimulation of nAChR in CeA negatively modulates the ethanol-induced chronic behavioral effects on anxiety in rats. It is proposed that nAChR antagonists might be useful in the treatment of alcohol use disorder and ethanol withdrawal-related anxiety-like behavior.
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Affiliation(s)
- Antariksha Duratkar
- Department of Pharmacology, J.L. Chaturvedi College of Pharmacy, Nagpur, Maharashtra
| | - Richa Patel
- Department of Pharmacy, Guru Ghasidas Vishwavidyalaya, Koni, Bilaspur, Chhattisgarh, India
| | - Nishant Sudhir Jain
- Department of Pharmacology, J.L. Chaturvedi College of Pharmacy, Nagpur, Maharashtra
- Department of Pharmacy, Guru Ghasidas Vishwavidyalaya, Koni, Bilaspur, Chhattisgarh, India
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2
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Palombo P, Maeda R, Riberti Zaniboni C, Antonagi Engi S, Yokoyama T, Bonetti Bertagna N, Anesio A, Cristina Bianchi P, Righi T, Emily Boaventura Tavares G, Souccar C, da Silva FBR, Cardoso Cruz F. Unlocking the role of dorsal hippocampal α4β2 nicotinic acetylcholine receptors in Ethanol-Induced conditioned place preference in mice. Neurosci Lett 2024; 824:137666. [PMID: 38331019 DOI: 10.1016/j.neulet.2024.137666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/22/2024] [Accepted: 02/01/2024] [Indexed: 02/10/2024]
Abstract
Alcohol Use Disorder (AUD) presents a significant and challenging public health concern, marked by a dearth of effective pharmacological treatments. Understanding the neurobiological underpinnings of AUD is of paramount importance for the development of efficacious interventions. The process of addiction entails the acquisition of associative behaviors, prominently engaging the dorsal region of the hippocampus for encoding these associative memories. Nicotinic receptor systems have been implicated in mediating the rewarding effects of ethanol, as well as memory and learning processes. In our current investigation, we delved into the role of α4β2 nicotinic acetylcholine receptors (nAChRs) within the dorsal hippocampus in the context of ethanol-induced conditioned place preference (CPP), a robust model for scrutinizing the rewarding properties and drug-associated behaviors. To establish CPP, ethanol (2 g/kg) was administered intraperitoneally during a 8-day conditioning phase. Fos immunohistochemistry was employed to assess the involvement of discrete subregions within the dorsal hippocampus in ethanol-induced CPP. Additionally, we probed the influence of α4β2 nAChRs on CPP via microinjections of a selective nAChR antagonist, dihydro-β-erythroidine (DHBE, at dosages of 6, 12, and 18 µg/0.5 µL per hemisphere) within the hippocampus. Our results unveiled that ethanol-induced CPP was associated with an increase Fos -positive cells in various subregions of the dorsal hippocampus, including CA1, CA2, CA3, and the dentate gyrus. Intrahippocampal administration of DHBE (at doses of 6 and 18 µg/0.50 µL per hemisphere) effectively blocked ethanol-induced CPP, while leaving locomotor activity unaffected. These findings underscore the critical involvement of the dorsal hippocampus and α4β2 nAChRs in the acquisition of ethanol-associated learning and reward.
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Affiliation(s)
- Paola Palombo
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
| | - Roberta Maeda
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Caroline Riberti Zaniboni
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Sheila Antonagi Engi
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Thais Yokoyama
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Natalia Bonetti Bertagna
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Augusto Anesio
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Paula Cristina Bianchi
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Thamires Righi
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Caden Souccar
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Fabio Cardoso Cruz
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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Gheidi A, Fitzpatrick CJ, Gregory JD, Morrow JD. Nicotinic and muscarinic acetylcholine receptor antagonism dose-dependently decreases sign- but not goal-tracking behavior in male rats. Psychopharmacology (Berl) 2023; 240:871-880. [PMID: 36795109 PMCID: PMC10599605 DOI: 10.1007/s00213-023-06328-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 01/27/2023] [Indexed: 02/17/2023]
Abstract
RATIONALE Acetylcholinergic antagonists have shown some promise in reducing addiction-related behaviors in both preclinical and clinical studies. However, the psychological mechanisms by which these drugs are able to affect addictive behavior remain unclear. A particular key process for the development of addiction is the attribution of incentive salience to reward-related cues, which can be specifically measured in animals using a Pavlovian conditioned approach procedure. When confronted with a lever that predicts food delivery, some rats engage with the lever directly (i.e., they sign track), indicating attribution of incentive-motivational properties to the lever itself. In contrast, others treat the lever as a predictive cue and approach the location of impending food delivery (i.e., they goal track), without treating the lever itself as a reward. OBJECTIVES We tested whether systemic antagonism of the either nicotinic or muscarinic acetylcholine receptors would selectively affect sign- or goal-tracking behavior, indicating a selective effect on incentive salience attribution. METHODS A total of 98 male Sprague Dawley rats were either given the muscarinic antagonist scopolamine (100, 50, or 10 µg/kg i.p.) or the nicotinic antagonist mecamylamine (0.3, 1.0, or 3 mg/kg i.p.) before being trained on a Pavlovian conditioned approach procedure. RESULTS Scopolamine dose-dependently decreased sign tracking behavior and increased goal-tracking behavior. Mecamylamine reduced sign-tracking but did not affect goal-tracking behavior. CONCLUSIONS Antagonism of either muscarinic or nicotinic acetylcholine receptors can reduce incentive sign-tracking behavior in male rats. This effect appears to be specifically due to a reduction in incentive salience attribution since goal-tracking either increased or was not affected by these manipulations.
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Affiliation(s)
- Ali Gheidi
- Department of Biomedical Sciences, Mercer University, Macon, USA
| | | | - Jordan D Gregory
- Department of Psychiatry, University of Michigan, Ann Arbor, USA
| | - Jonathan D Morrow
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, USA.
- Department of Psychiatry, University of Michigan, Ann Arbor, USA.
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Kamens HM, Flarend G, Horton WJ. The role of nicotinic receptors in alcohol consumption. Pharmacol Res 2023; 190:106705. [PMID: 36813094 PMCID: PMC10083870 DOI: 10.1016/j.phrs.2023.106705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/14/2023] [Accepted: 02/19/2023] [Indexed: 02/22/2023]
Abstract
The use of alcohol causes significant morbidity and mortality across the globe. Alcohol use disorder (AUD) is defined by the excessive use of this drug despite a negative impact on the individual's life. While there are currently medications available to treat AUD, they have limited efficacy and several side effects. As such, it is essential to continue to look for novel therapeutics. One target for novel therapeutics is nicotinic acetylcholine receptors (nAChRs). Here we systematically review the literature on the involvement of nAChRs in alcohol consumption. Data from both genetic and pharmacology studies provide evidence that nAChRs modulate alcohol intake. Interestingly, pharmacological modulation of all nAChR subtypes examined can decrease alcohol consumption. The reviewed literature demonstrates that nAChRs should continue to be investigated as novel therapeutics for AUD.
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Affiliation(s)
- Helen M Kamens
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA 16802, United States.
| | - Geneva Flarend
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA 16802, United States
| | - William J Horton
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA 16802, United States
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Straub CJ, Rusali LE, Kremiller KM, Riley AP. What We Have Gained from Ibogaine: α3β4 Nicotinic Acetylcholine Receptor Inhibitors as Treatments for Substance Use Disorders. J Med Chem 2023; 66:107-121. [PMID: 36440853 PMCID: PMC10034762 DOI: 10.1021/acs.jmedchem.2c01562] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For decades, ibogaine─the main psychoactive alkaloid found in Tabernanthe iboga─has been investigated as a possible treatment for substance use disorders (SUDs) due to its purported ability to interrupt the addictive properties of multiple drugs of abuse. Of the numerous pharmacological actions of ibogaine and its derivatives, the inhibition of α3β4 nicotinic acetylcholine receptors (nAChRs), represents a probable mechanism of action for their apparent anti-addictive activity. In this Perspective, we examine several classes of compounds that have been discovered and developed to target α3β4 nAChRs. Specifically, by focusing on compounds that have proven efficacious in pre-clinical models of drug abuse and have been evaluated clinically, we highlight the promising potential of the α3β4 nAChRs as viable targets to treat a wide array of SUDs. Additionally, we discuss the challenges faced by the existing classes of α3β4 nAChR ligands that must be overcome to develop them into therapeutic treatments.
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Affiliation(s)
- Carolyn J Straub
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Lisa E Rusali
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Kyle M Kremiller
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Andrew P Riley
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
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Gupta S, Mukhopadhyay S, Mitra A. Therapeutic potential of GHSR-1A antagonism in alcohol dependence, a review. Life Sci 2022; 291:120316. [PMID: 35016882 DOI: 10.1016/j.lfs.2022.120316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 11/28/2022]
Abstract
Growth hormone secretagogue receptor type 1A (GHSR-1A) is a functional receptor of orexigenic peptide ghrelin and is highly expressed in mesolimbic dopaminergic systems that regulate incentive value of artificial reward in substance abuse. Interestingly, GHSR-1A has also shown ligand-independent constitutive activity. Alcohol use disorder (AUD) is one of the growing concerns worldwide as it involves complex neuro-psycho-endocrinological interactions. Positive correlation of acylated ghrelin and alcohol-induced human brain response in the right and left ventral striatum are evident. In the last decade, the beneficial effects of ghrelin receptor (GHSR-1A) antagonism to suppress artificial reward circuitries and induce self-control for alcohol consumption have drawn significant attention from researchers. In this updated review, we summarize the available recent preclinical, clinical, and experimental data to discuss functional, molecular actions of central ghrelin-GHSR-1A signaling in different craving levels for alcohol as well as to promote "GHSR-1A antagonism" as one of the potential therapies in early abstinence.
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Affiliation(s)
- Shreyasi Gupta
- Department of Zoology, Triveni Devi Bhalotia College, Raniganj, Paschim Bardhaman 713 347, West Bengal, India
| | - Sanchari Mukhopadhyay
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Hombegowda Nagar, Bengaluru 560029, India
| | - Arkadeep Mitra
- Department of Zoology, City College, 102/1, Raja Rammohan Sarani, Kolkata 700 009, West Bengal, India.
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Kassner M, Eaton JB, Tang N, Petit JL, Meurice N, Yin HH, Whiteaker P. High-throughput cell-based assays for identifying antagonists of multiple smoking-associated human nicotinic acetylcholine receptor subtypes. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2022; 27:68-76. [PMID: 35058178 PMCID: PMC8816891 DOI: 10.1016/j.slasd.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
There is substantial evidence that in addition to nicotine, other compounds found in tobacco smoke significantly influence smoking behavior. Further, recent years have seen an explosion in the availability of non-combusted products that deliver nicotine, such as e-cigarettes and “home-brew” vaping devices that are essentially unregulated. There are many thousands of compounds in tobacco smoke alone, and new products are constantly introducing new compounds. Uncovering which of these compounds are active, across multiple smoking-relevant subtypes of the nicotinic acetylcholine receptor (nAChR) that influence tobacco/nicotine addiction, requires a high-throughput screening (HTS) approach. Accordingly, we developed a panel of HTS-friendly cell-based assays, all performed in the same cellular background and using the same membrane potential dye readout, to measure the function of the α3β4-, α4β2-, and α6β2-nAChR subtypes. These subtypes have each been prominently and consistently associated with human smoking behavior. We validated our assays by performing pilot screening of an expanded set of the Prestwick FDA-approved drug library. The screens displayed excellent performance parameters, and moderate hit rates (mean of 1.2% across all three assays) were achieved when identifying antagonists (chosen since effects of endogenous antagonists on consumption of nicotine/tobacco products are under-studied). Validation rates using an orthogonal assay (86Rb+ efflux) averaged 73% across the three assays. The resulting panel of assays represents a valuable new platform with which to screen and identify nAChR subtype-selective compounds. This provides a resource for identifying smoking-related compounds in both combusted and non-combusted tobacco products, with potential relevance in the search for additional smoking-cessation therapies.
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Affiliation(s)
- Michelle Kassner
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States
| | - J Brek Eaton
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, United States
| | - Nanyun Tang
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States
| | - Joachim L Petit
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ 85259, United States
| | - Nathalie Meurice
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ 85259, United States
| | - Hongwei Holly Yin
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States.
| | - Paul Whiteaker
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, United States.
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8
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DeCristofano L, Decker S, Schulte MK, Suryanarayanan A. Desformylflustrabromine (dFBr), a positive allosteric modulator of the α 4β 2 nicotinic receptor modulates the hypnotic response to ethanol. Alcohol 2021; 93:35-44. [PMID: 33652092 DOI: 10.1016/j.alcohol.2021.02.005] [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] [Received: 12/07/2020] [Revised: 02/01/2021] [Accepted: 02/22/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Binge drinking can increase an individual's risk of developing alcohol use disorder (AUD). Ethanol targets multiple neurotransmitter systems; however, not much is known about its effects on the cholinergic system. Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels, the heteromeric α4β2 nAChR being a commonly expressed subtype. Desformylflustrabromine (dFBr), a positive allosteric modulator (PAM), increases the efficacy of α4β2 nAChR in vitro and has previously been shown to have translational potential. In this study, we investigated whether dFBr modulates the hypnotic response to ethanol. METHODS Ethanol-induced loss of righting reflex (LORR) duration was measured in the presence and absence of dFBr. The β2 nAChR selective antagonist dihydro-β-erythroidine (DHβE) was used to study the involvement of the β2 subunit. Additionally, we used a crosslinking-based western blot assay to estimate changes in total versus intracellular α4 nAChR protein in thalamic tissue of rats treated with vehicle, dFBr, ethanol, or ethanol and dFBr. Lastly, using Xenopus oocyte two-electrode voltage clamp (TEVC) studies, we determined the effects of ethanol and dFBr on α4β2 nAChR. RESULTS Pretreatment with 6 mg/kg dFBr reduced ethanol-induced LORR duration as compared to rats treated with ethanol alone. LORR studies with DHβE suggest that dFBr reduced ethanol-induced LORR duration via the β2 nAChR subunit. Crosslinking-based western analyses revealed that ethanol caused early increases in total and presumably surface thalamic α4 nAChR subunit protein levels. This ethanol-induced α4 nAChR upregulation was significantly reduced in rats pretreated with 6 mg/kg dFBr. In TEVC studies, ethanol potentiated ACh-induced currents in α4β2 nAChR, while it slightly reduced dFBr potentiation of maximal ACh currents. CONCLUSIONS Our results suggest that thalamic nAChRs containing the α4 subunit are rapidly upregulated by a single intoxicating dose of ethanol. Furthermore, dFBr, an α4β2 nAChR-selective PAM, significantly attenuates the hypnotic response to ethanol via actions on β2 nAChR. Overall, these results indicate that dFBr represents an option to reverse ethanol intoxication.
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9
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Therapeutic potential of ketamine for alcohol use disorder. Neurosci Biobehav Rev 2021; 126:573-589. [PMID: 33989669 DOI: 10.1016/j.neubiorev.2021.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 04/02/2021] [Accepted: 05/09/2021] [Indexed: 12/12/2022]
Abstract
Excessive alcohol consumption is involved in 1/10 of deaths of U.S. working-age adults and costs the country around $250,000,000 yearly. While Alcohol Use Disorder (AUD) pathology is complex and involves multiple neurotransmitter systems, changes in synaptic plasticity, hippocampal neurogenesis, and neural connectivity have been implicated in the behavioral characteristics of AUD. Depressed mood and stress are major determinants of relapse in AUD, and there is significant comorbidity between AUD, depression, and stress disorders, suggesting potential for overlap in their treatments. Disulfiram, naltrexone, and acamprosate are current pharmacotherapies for AUD, but these treatments have limitations, highlighting the need for novel therapeutics. Ketamine is a N-methyl-D-Aspartate receptor antagonist, historically used in anesthesia, but also affects other neurotransmitters systems, synaptic plasticity, neurogenesis, and neural connectivity. Currently under investigation for treating AUDs and other Substance Use Disorders (SUDs), ketamine has strong support for efficacy in treating clinical depression, recently receiving FDA approval. Ketamine's effect in treating depression and stress disorders, such as PTSD, and preliminary evidence for treating SUDs further suggests a role for treating AUDs. This review explores the behavioral and neural evidence for treating AUDs with ketamine and clinical data on ketamine therapy for AUDs and SUDs.
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10
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Miller CN, Kamens HM. The role of nicotinic acetylcholine receptors in alcohol-related behaviors. Brain Res Bull 2020; 163:135-142. [PMID: 32707263 DOI: 10.1016/j.brainresbull.2020.07.017] [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: 03/17/2020] [Revised: 06/23/2020] [Accepted: 07/17/2020] [Indexed: 12/29/2022]
Abstract
Alcohol use disorder (AUD) causes an alarming economic and health burden in the United States. Unfortunately, this disease does not exist in isolation; AUD is highly comorbid with nicotine use. Results from both human and animal models demonstrate a genetic correlation between alcohol and nicotine behaviors. These data support the idea of shared genetic and neural mechanisms underlying these behaviors. Nicotine acts directly at nicotinic acetylcholine receptors (nAChR) to have its pharmacological effect. Interestingly, alcohol also acts both directly and indirectly at these receptors. Research utilizing genetically engineered rodents and pharmacological manipulations suggest a role for nAChR in several ethanol behaviors. The current manuscript collates this literature and discusses findings that implicate specific nAChR subunits in ethanol phenotypes. These data suggest future directions for targeting nAChR as novel therapeutics for AUD.
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Affiliation(s)
- C N Miller
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, 16802, United States
| | - H M Kamens
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, 16802, United States.
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11
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Rice J, Gu C. Function and Mechanism of Myelin Regulation in Alcohol Abuse and Alcoholism. Bioessays 2019; 41:e1800255. [PMID: 31094014 DOI: 10.1002/bies.201800255] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/31/2019] [Indexed: 12/26/2022]
Abstract
Excessive alcohol use has adverse effects on the central nervous system (CNS) and can lead to alcohol use disorders (AUDs). Recent studies have suggested that myelin reductions may directly contribute to CNS dysfunctions associated with AUDs. Myelin consists of compact lipid membranes wrapped around axons to provide electrical insulation and trophic support. Regulation of myelin is considered as a new form of neural plasticity due to its profound impacts on the computation of neural networks. In this review, the authors first discuss experimental evidence showing how alcohol exposure causes demyelination in different brain regions, often accompanied by deficits in cognition and emotion. Next, they discuss postulated molecular and cellular mechanisms underlying alcohol's impact on myelin. It is clear that more extensive investigations are needed in this important but underexplored research field in order to gain a better understanding of the myelin-behavior relationship and to develop new treatment strategies for AUDs.
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Affiliation(s)
- James Rice
- Department of Biological Chemistry and Pharmacology, The Ohio State University, 1060 Carmack Road, Columbus, OH, 43210, USA
| | - Chen Gu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, 1060 Carmack Road, Columbus, OH, 43210, USA
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12
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Brain region specific glucagon-like peptide-1 receptors regulate alcohol-induced behaviors in rodents. Psychoneuroendocrinology 2019; 103:284-295. [PMID: 30771711 DOI: 10.1016/j.psyneuen.2019.02.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 01/03/2023]
Abstract
Glucagon-like peptide 1 (GLP-1), an incretin hormone that reduces food intake, was recently established as a novel regulator of alcohol-mediated behaviors. Clinically available analogues pass freely into the brain, but the mechanisms underlying GLP-1-modulated alcohol reward remains largely unclear. GLP-1 receptors (GLP-1R) are expressed throughout the nuclei of importance for acute and chronic effects of alcohol, such as the laterodorsal tegmental area (LDTg), the ventral tegmental area (VTA) and the nucleus accumbens (NAc). We therefore evaluated the effects of bilateral infusion of the GLP-1R agonist exendin-4 (Ex4) into NAc shell, anterior (aVTA), posterior (pVTA) or LDTg on the acute alcohol-induced locomotor stimulation and memory of alcohol reward in the conditioned place preference (CPP) model in mice, as well as on alcohol intake in rats consuming high amounts of alcohol for 12 weeks. Ex4 into the NAc shell blocks alcohol-induced locomotor stimulation and memory of alcohol reward as well as decreases alcohol intake. The GLP-1R expression in NAc is elevated in high compared to low alcohol-consuming rats. On the contrary, GLP-1R activation in the aVTA does not modulate alcohol-induced behaviors. Ex4 into the pVTA prevents alcohol-induced locomotor simulation, but does neither modulate CPP-dependent alcohol memory nor alcohol intake. Intra-LDTg-Ex4 attenuates alcohol-induced locomotor stimulation and reduces alcohol intake, but does not affect memory of alcohol reward. Collectively, these data provide additional knowledge of the functional role of GLP-1R in reward-related areas for alcohol-mediated behaviors and further support GLP-1R as a potential treatment target for alcohol use disorder.
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13
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Gao F, Chen D, Ma X, Sudweeks S, Yorgason JT, Gao M, Turner D, Eaton JB, McIntosh JM, Lukas RJ, Whiteaker P, Chang Y, Steffensen SC, Wu J. Alpha6-containing nicotinic acetylcholine receptor is a highly sensitive target of alcohol. Neuropharmacology 2019; 149:45-54. [PMID: 30710570 PMCID: PMC7323585 DOI: 10.1016/j.neuropharm.2019.01.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 01/01/2019] [Accepted: 01/17/2019] [Indexed: 02/05/2023]
Abstract
Alcohol use disorder (AUD) is a serious public health problem that results in tremendous social, legal and medical costs to society. Unlike other addictive drugs, there is no specific molecular target for ethanol (EtOH). Here, we report a novel molecular target that mediates EtOH effects at concentrations below those that cause legally-defined inebriation. Using patch-clamp recording of human α6*-nicotinic acetylcholine receptor (α6*-nAChR) function when heterologously expressed in SH-EP1 human epithelial cells, we found that 0.1-5 mM EtOH significantly enhances α6*-nAChR-mediated currents with effects that are dependent on both EtOH and nicotine concentrations. EtOH exposure increased both whole-cell current rising slope and decay constants. This EtOH modulation was selective for α6*-nAChRs since it did not affect α3β4-, α4β2-, or α7-nAChRs. In addition, 5 mM EtOH also increased the frequency and amplitude of dopaminergic neuron transients in mouse brain nucleus accumbens slices, that were blocked by the α6*-nAChR antagonist, α-conotoxin MII, suggesting a role for native α6*-nAChRs in low-dose EtOH effects. Collectively, our data suggest that α6*-nAChRs are sensitive targets mediating low-dose EtOH effects through a positive allosteric mechanism, which provides new insight into mechanisms involved in pharmacologically-relevant alcohol effects contributing to AUD.
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Affiliation(s)
- Fenfei Gao
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong, 51504, China; Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Dejie Chen
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA; Department of Neurology, Yunfu People's Hospital, Yunfu, Guangdong, 527300, China
| | - Xiaokuang Ma
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong, 51504, China; Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Sterling Sudweeks
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, 84602, USA
| | - Jordan T Yorgason
- Department of Psychology and Neuroscience, Brigham Young University, Provo, UT, 84602, USA
| | - Ming Gao
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Dharshaun Turner
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Jason Brek Eaton
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - J Michael McIntosh
- George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, UT, USA 84108, USA
| | - Ronald J Lukas
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Paul Whiteaker
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Yongchang Chang
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Scott C Steffensen
- Department of Psychology and Neuroscience, Brigham Young University, Provo, UT, 84602, USA
| | - Jie Wu
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong, 51504, China; Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA; Department of Neurology, Yunfu People's Hospital, Yunfu, Guangdong, 527300, China.
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14
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Dawson A, Wolstenholme JT, Roni MA, Campbell VC, Jackson A, Slater C, Bagdas D, Perez EE, Bettinger JC, De Biasi M, Miles MF, Damaj MI. Knockout of alpha 5 nicotinic acetylcholine receptors subunit alters ethanol-mediated behavioral effects and reward in mice. Neuropharmacology 2018; 138:341-348. [PMID: 29944862 DOI: 10.1016/j.neuropharm.2018.06.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/19/2018] [Accepted: 06/22/2018] [Indexed: 01/03/2023]
Abstract
Evidence suggests that there is an association between polymorphisms in the α5 nicotinic acetylcholine receptor (nAChR) subunit and risk of developing alcohol dependence in humans. The α5 nAChR subunit has also recently been shown to modulate some of the acute response to ethanol in mice. The aim of the current study was to further characterize the role of α5-containing (α5*) nAChRs in acute ethanol responsive behaviors, ethanol consumption and ethanol preference in mice. We conducted a battery of tests in male α5 knockout (KO) mice for a range of ethanol-induced behaviors including hypothermia, hypnosis, and anxiolysis. We also investigated the effects of α5* nAChR on ethanol reward using the Conditioned Place Preference (CPP) assay. Further, we tested the effects of gene deletion on drinking behaviors using the voluntary ethanol consumption in a two-bottle choice assay and Drinking in the Dark (DID, with or without stress) paradigm. We found that deletion of the α5 nAChR subunit enhanced ethanol-induced hypothermia, hypnosis, and an anxiolytic-like response in comparison to wild-type controls. The α5 KO mice showed reduced CPP for ethanol, suggesting that the rewarding properties of ethanol are decreased in mutant mice. Interestingly, Chrna5 gene deletion had no effect on basal ethanol drinking behavior, or ethanol metabolism, but did decrease ethanol intake in the DID paradigm following restraint stress. Taken together, we provide new evidence that α5 nAChRs are involved in some but not all of the behavioral effects of ethanol. Our results highlight the importance of nAChRs as a possible target for the treatment of alcohol dependence.
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Affiliation(s)
- Anton Dawson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA
| | - Jennifer T Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA
| | - Monzurul A Roni
- Department of Pharmaceutical Sciences, Hampton University School of Pharmacy, Hampton, VA, 23668, USA
| | - Vera C Campbell
- Department of Pharmaceutical Sciences, Hampton University School of Pharmacy, Hampton, VA, 23668, USA
| | - Asti Jackson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA
| | - Cassandra Slater
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA
| | - Deniz Bagdas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA
| | - Erika E Perez
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA
| | - Mariella De Biasi
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael F Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0613, USA.
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15
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Touchette JC, Maertens JJ, Mason MM, O'Rourke KY, Lee AM. The nicotinic receptor drug sazetidine-A reduces alcohol consumption in mice without affecting concurrent nicotine consumption. Neuropharmacology 2018; 133:63-74. [PMID: 29355641 PMCID: PMC5858984 DOI: 10.1016/j.neuropharm.2018.01.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 01/09/2018] [Accepted: 01/13/2018] [Indexed: 01/01/2023]
Abstract
Alcohol and nicotine addiction are frequently co-morbid. The nicotinic acetylcholine receptors (nAChRs) are critical for both alcohol and nicotine addiction mechanisms, since nAChR drugs that reduce nicotine consumption have been shown to also reduce alcohol consumption. Sazetidine-A, a pre-clinical nAChR drug with agonist and desensitizing effects at α4β2 and α7 nAChRs, has been reported to reduce alcohol consumption and nicotine self-administration in rats when administered at high doses. However, this effect has not been replicated in mice. In this study, we examined the effect of sazetidine-A on alcohol and nicotine consumption in male and female mice utilizing voluntary oral consumption procedures previously developed in our lab. We found that sazetidine-A (1 mg/kg, i.p) reduced overnight alcohol consumption, but did not affect nicotine consumption when presented either alone or concurrently with alcohol. Sazetidine-A did not reduce water or saccharin consumption at any dose tested. In a chronic co-consumption experiment in which either alcohol or nicotine was re-introduced after one week of forced abstinence, sazetidine-A attenuated post-abstinence consumption of alcohol but not nicotine. Sazetidine-A also significantly reduced alcohol consumption in an acute, binge drinking-in-the-dark procedure. Finally, we tested the effect of sazetidine-A on alcohol withdrawal, and found that sazetidine-A significantly reduced handling-induced convulsions during alcohol withdrawal. Collectively, these data suggest a novel role for the nAChR targets of sazetidine-A in specifically mediating alcohol consumption, separate from the involvement of nAChRs in mediating nicotine consumption. Delineation of this pathway may provide insight into novel therapies for the treatment of alcohol use disorders.
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Affiliation(s)
| | - Jamie J Maertens
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Margaret M Mason
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Kyu Y O'Rourke
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Anna M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA.
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16
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Klenowski PM, Tapper AR. Molecular, Neuronal, and Behavioral Effects of Ethanol and Nicotine Interactions. Handb Exp Pharmacol 2018; 248:187-212. [PMID: 29423839 DOI: 10.1007/164_2017_89] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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17
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Abreu-Villaça Y, Manhães AC, Krahe TE, Filgueiras CC, Ribeiro-Carvalho A. Tobacco and alcohol use during adolescence: Interactive mechanisms in animal models. Biochem Pharmacol 2017; 144:1-17. [DOI: 10.1016/j.bcp.2017.06.113] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/05/2017] [Indexed: 12/13/2022]
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18
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α6β2 nicotinic acetylcholine receptors influence locomotor activity and ethanol consumption. Alcohol 2017; 61:43-49. [PMID: 28457669 DOI: 10.1016/j.alcohol.2017.02.178] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 02/10/2017] [Accepted: 02/11/2017] [Indexed: 12/13/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) in the mesolimbic dopamine system have been implicated in ethanol behaviors. In particular, work in genetically engineered mice has demonstrated that α6-containing nAChRs are involved in ethanol consumption and sedation. A limitation of these studies is that the alteration in the receptor was present throughout development. The recently described α6β2 antagonist, N,N-decane-1,10-diyl-bis-3-picolinium diiodide (bPiDI), now makes it possible to test for the involvement of these receptors using a pharmacological approach. The aim of this study was to examine the role of α6β2 nAChRs in ethanol behaviors using a pharmacological approach. Adolescent C57BL/6J mice were treated with bPiDI 30 min prior to testing the mice for binge-like ethanol consumption in the drinking-in-the-dark (DID) test, ethanol-induced motor incoordination using the balance beam, and ethanol-induced sedation using the Loss of Righting Reflex (LORR) paradigm. Adolescent animals were chosen because they express a high amount of α6 mRNA relative to adult animals. Control studies were also performed to determine the effect of bPiDI on locomotor activity and ethanol metabolism. Female mice treated with 20 mg/kg bPiDI had reduced locomotor activity compared to saline-treated animals during the first 30 min following an acute injection. Pretreatment with the α6β2 antagonist reduced adolescent ethanol consumption but also reduced saccharin consumption. No significant effects were observed on ethanol-induced ataxia, sedation, or metabolism. This study provides evidence that α6β2 nAChRs are involved in locomotor activity as well as ethanol and saccharin consumption in adolescent animals.
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Yardley MM, Ray LA. Medications development for the treatment of alcohol use disorder: insights into the predictive value of animal and human laboratory models. Addict Biol 2017; 22:581-615. [PMID: 26833803 DOI: 10.1111/adb.12349] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 11/09/2015] [Accepted: 11/13/2015] [Indexed: 12/20/2022]
Abstract
Development of effective treatments for alcohol use disorder (AUD) represents an important public health goal. This review provides a summary of completed preclinical and clinical studies testing pharmacotherapies for the treatment of AUD. We discuss opportunities for improving the translation from preclinical findings to clinical trial outcomes, focusing on the validity and predictive value of animal and human laboratory models of AUD. Specifically, while preclinical studies of medications development have offered important insights into the neurobiology of the disorder and alcohol's molecular targets, limitations include the lack of standardized methods and streamlined processes whereby animal studies can readily inform human studies. Behavioral pharmacology studies provide a less expensive and valuable opportunity to assess the feasibility of a pharmacotherapy prior to initiating larger scale clinical trials by providing insights into the mechanism of the drug, which can then inform recruitment, analyses, and assessments. Summary tables are provided to illustrate the wide range of preclinical, human laboratory, and clinical studies of medications development for alcoholism. Taken together, this review highlights the challenges associated with animal paradigms, human laboratory studies, and clinical trials with the overarching goal of advancing treatment development and highlighting opportunities to bridge the gap between preclinical and clinical research.
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Affiliation(s)
- Megan M. Yardley
- Department of Psychology; University of California, Los Angeles; Los Angeles CA USA
| | - Lara A. Ray
- Department of Psychology; University of California, Los Angeles; Los Angeles CA USA
- Department of Psychiatry and Biobehavioral Sciences; University of California, Los Angeles; Los Angeles CA USA
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20
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Effect of Lowering the Dose of Varenicline on Alcohol Self-administration in Drinkers With Alcohol Use Disorders. J Addict Med 2017; 10:166-73. [PMID: 27159341 DOI: 10.1097/adm.0000000000000208] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Varenicline (2 mg/d) has been shown to be efficacious in reducing alcohol consumption. A lower dose of varenicline may be effective in reducing alcohol use while minimizing the potential for side effects. METHODS This double-blind, placebo-controlled investigation examined the effect of varenicline (0, 1, 2 mg/d) on alcohol consumption in nontreatment-seeking adults meeting the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV) criteria for alcohol use disorders (N = 60). Following 7 days of medication pretreatment, participants were administered a low fixed dose of alcohol (0.3 g/dL), and subjective and physiologic responses were assessed. A 2-hour ad libitum alcohol self-administration period followed. We also explored relationships between plasma varenicline levels and consumption. RESULTS Overall, frequency and severity of adverse events were minimal. The 1 mg/d dose reduced the frequency of insomnia compared with the 2 mg/d dose. The 2 mg/d varenicline dose versus placebo reduced alcohol craving and showed limited effect on reduced alcohol consumption. Alcohol craving and consumption did not differ between the 1 mg/d varenicline dose versus placebo. Trough varenicline plasma levels greater than or equal to 3 ng/mL were associated with reduced drinking and levels greater than or equal to 5 ng/mL were associated with reduced heavy drinking. CONCLUSIONS Overall, we found no evidence supporting an effect of 1 mg/d varenicline on craving or consumption, suggesting that doses of varenicline less than 2 mg/d may not be effective in reducing alcohol-related outcomes. Importantly, results suggest that higher plasma levels of varenicline may be needed to maximize the effect of varenicline on alcohol consumption and should be investigated in drinkers meeting criteria for alcohol use disorders.
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21
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Guildford MJ, Sacino AV, Tapper AR. Modulation of ethanol reward sensitivity by nicotinic acetylcholine receptors containing the α6 subunit. Alcohol 2016; 57:65-70. [PMID: 27793544 DOI: 10.1016/j.alcohol.2016.08.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/03/2016] [Accepted: 08/03/2016] [Indexed: 12/21/2022]
Abstract
The prevalent co-abuse of nicotine and alcohol suggests a common neural mechanism underlying the actions of the two drugs. Nicotine, the addictive component of tobacco, activates nicotinic acetylcholine receptors (nAChRs) containing the α6 subunit (α6* nAChRs) in dopaminergic (DAergic) neurons of the ventral tegmental area (VTA), a region known to be crucial for drug reward. Recent evidence suggests that ethanol may potentiate ACh activation of these receptors as well, although whether α6* nAChR expression is necessary for behavioral effects of acute ethanol exposure is unknown. We compared binge-like ethanol consumption and ethanol reward sensitivity between knockout (KO) mice that do not express chrna6 (the gene encoding the α6 nAChR subunit, the α6 KO line) and wild-type (WT) littermates using the Drinking-in-the-Dark (DID) and Conditioned Place Preference (CPP) assay, respectively. In the DID assay, α6 KO female and male mice consumed ethanol similarly to WT mice at all concentrations tested. In the CPP assay, 2.0-g/kg and 3.0-g/kg, but not 0.5-mg/kg, ethanol conditioned a place preference in WT female and male mice, whereas only 2.0-g/kg ethanol conditioned a place preference in α6 KO mice. Acute challenge with ethanol reduced locomotor activity, an effect that developed tolerance with repeated injections, similarly between genotypes in both female and male mice. Together, these data indicate that expression of α6* nAChRs is not required for binge-like ethanol consumption and reward, but modulate sensitivity to the rewarding properties of the drug.
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22
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Kohut SJ. Interactions between nicotine and drugs of abuse: a review of preclinical findings. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2016; 43:155-170. [PMID: 27589579 DOI: 10.1080/00952990.2016.1209513] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Polysubstance abuse is common among substance-use disorder patients, and nicotine is one of the most commonly co-used substances. Epidemiological and clinical laboratory studies suggest that nicotine, when combined with other drugs of abuse, increases intake of one or both substances. This review focuses on the preclinical literature regarding nicotine's interaction with alcohol, stimulants (i.e., cocaine, amphetamines), opioids (i.e., morphine, heroin), and Δ9-tetrahydrocannabinol (THC). The current understanding of how these various classes of abused drugs may interact with nicotine on behavioral, physiological, and pharmacological indices that may be important in maintaining co-use of one or both substances in human populations are highlighted. Suggestions as to future areas of research and gaps in knowledge are offered.
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Affiliation(s)
- Stephen J Kohut
- a McLean Hospital and Department of Psychiatry, Harvard Medical School , Belmont , MA , USA
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23
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Metabolic shift of the kynurenine pathway impairs alcohol and cocaine seeking and relapse. Psychopharmacology (Berl) 2016; 233:3449-59. [PMID: 27475106 DOI: 10.1007/s00213-016-4384-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 07/16/2016] [Indexed: 12/31/2022]
Abstract
RATIONALE The glutamatergic system plays a key role in the maintenance of drug use and development of drug-related conditioned behaviours. In particular, hyper-glutamatergic activity and N-methyl-D-aspartate receptor (NMDAR) activation may drive drug craving and relapse. Inhibition of kynurenine-3-monooxygenase (KMO) shifts the metabolic kynurenine pathway towards production of kynurenic acid, which leads to a reduction of glutamatergic/NMDAR activity via different mechanisms. OBJECTIVES In this study, we investigated whether drug-seeking and relapse behaviour could be modified by the metabolic shift of endogenous kynurenine pathway. METHODS An inhibitor of kynurenine-3-monooxygenase (KMO) Ro61-8048 (4 and 40 mg/kg) and its prodrug JM6 (100 and 200 mg/kg) were tested in two behavioural rat models for drug seeking and relapse-the alcohol deprivation effect (ADE) model in long-term alcohol-drinking rats and the model of cue-induced reinstatement of alcohol- and cocaine-seeking behaviour. RESULTS Our results show that relapse-like alcohol drinking during the ADE was abolished by repeated intraperitoneal administration of Ro61-8048 and significantly reduced by its oral prodrug JM6. Cue-induced reinstatement of both alcohol- and cocaine-seeking behaviour was also abolished by administration of Ro61-8048. CONCLUSIONS Pharmacological enhancement of endogenous kynurenic acid levels provides a novel treatment strategy to interfere with glutamatergic/NMDAR activity as well as with craving and relapse in alcohol-dependent patients and drug addicts.
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24
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Srisontiyakul J, Kastman HE, Krstew EV, Govitrapong P, Lawrence AJ. The Nicotinic α6-Subunit Selective Antagonist bPiDI Reduces Alcohol Self-Administration in Alcohol-Preferring Rats. Neurochem Res 2016; 41:3206-3214. [PMID: 27573375 DOI: 10.1007/s11064-016-2045-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 10/21/2022]
Abstract
Cigarettes and alcohol are the most abused substances in the world and are commonly co-abused. Nicotine primarily acts in the brain on nicotinic acetylcholine receptors (nAChR), which are also a target for alcohol. The alpha6 subunit of nAChR is expressed almost exclusively in the brain reward system and may modulate the rewarding properties of alcohol and nicotine. Recently, N,N-decane-1,10-diyl-bis-3-picolinium diiodide (bPiDI) was synthesized as a selective, brain penetrant α6 subunit antagonist that reduces nicotine self-administration. The current study aimed to examine the effects of bPiDI on alcohol self-administration in inbred alcohol-preferring (iP) rats. Adult, male iP rats were trained to self-administer alcohol or sucrose. Once stable responding was achieved, rats were injected with bPiDI (1, 3 mg/kg, i.p.) and tested for self-administration under fixed and progressive ratio schedules of reinforcement. They subsequently underwent extinction, in which no rewards or cues were presented in the operant chambers. Then, they were injected with bPiDI prior to testing for cue-induced reinstatement of reward seeking. bPiDI (3 mg/kg) significantly reduced alcohol self-administration in both fixed and progressive ratios without any effects on sucrose self-administration or locomotor activity. In contrast, bPiDI (3 mg/kg) did not inhibit cue-induced reinstatement of either alcohol or sucrose seeking. The results support the involvement of α6 containing nAChR in reinforcing effects of alcohol, but not relapse to alcohol-seeking, without any impact on responding for a natural reward or general activity. bPiDI may be a potential lead molecule for a therapeutic strategy to limit nicotine and alcohol consumption.
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Affiliation(s)
- Jirawoot Srisontiyakul
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Hanna E Kastman
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia
| | - Elena V Krstew
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia
| | - Piyarat Govitrapong
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand.,Center for Neuroscience and Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia. .,Florey Department of Neuroscience, University of Melbourne, Parkville, VIC, Australia.
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25
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Cross SJ, Lotfipour S, Leslie FM. Mechanisms and genetic factors underlying co-use of nicotine and alcohol or other drugs of abuse. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2016; 43:171-185. [PMID: 27532746 DOI: 10.1080/00952990.2016.1209512] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Concurrent use of tobacco and alcohol or psychostimulants represents a major public health concern, with use of one substance influencing consumption of the other. Co-abuse of these drugs leads to substantial negative health outcomes, reduced cessation, and high economic costs, but the underlying mechanisms are poorly understood. Epidemiological data suggest that tobacco use during adolescence plays a particularly significant role. Adolescence is a sensitive period of development marked by major neurobiological maturation of brain regions critical for reward processing, learning and memory, and executive function. Nicotine exposure during this time produces a unique and long-lasting vulnerability to subsequent substance use, likely via actions at cholinergic, dopaminergic, and serotonergic systems. In this review, we discuss recent clinical and preclinical data examining the genetic factors and mechanisms underlying co-use of nicotine and alcohol or cocaine and amphetamines. We evaluate the critical role of nicotinic acetylcholine receptors throughout, and emphasize the dearth of preclinical studies assessing concurrent drug exposure. We stress important age and sex differences in drug responses, and highlight a brief, low-dose nicotine exposure paradigm that may better model early use of tobacco products. The escalating use of e-cigarettes among youth necessitates a closer look at the consequences of early adolescent nicotine exposure on subsequent alcohol and drug abuse.
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Affiliation(s)
- Sarah J Cross
- a Department of Anatomy & Neurobiology , School of Medicine, University of California , Irvine , CA , USA
| | - Shahrdad Lotfipour
- b Department of Emergency Medicine , School of Medicine, University of California , Irvine , CA , USA.,c Department of Pharmacology , School of Medicine, University of California , Irvine , CA , USA
| | - Frances M Leslie
- a Department of Anatomy & Neurobiology , School of Medicine, University of California , Irvine , CA , USA.,c Department of Pharmacology , School of Medicine, University of California , Irvine , CA , USA
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26
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Tribute to: Self-administered nicotine activates the mesolimbic dopamine system through the ventral tegmental area [William Corrigall, Kathleen Coen and Laurel Adamson, Brain Res. 653 (1994) 278-284]. Brain Res 2016; 1645:61-4. [PMID: 26867702 DOI: 10.1016/j.brainres.2015.12.064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/19/2015] [Indexed: 12/20/2022]
Abstract
In this paper, Dr. Corrigall and collaborators described elegant experiments designed to elucidate the neurobiology of nicotine reinforcement. The nicotinic receptor antagonist dihydro-β-erythroidine (DHβE) was infused in the ventral tegmental area (VTA) or nucleus accumbens (NAC) of rats trained to self-administer nicotine intravenously. Additionally, DHβE was infused in the VTA of rats trained to self-administer food or cocaine, and nicotine self-administration was assessed in rats with lesions to the peduculopontine tegmental nucleus (PPT). A number of key themes emerged from this fundamental study that remain relevant today. The primary finding was that infusions of DHβE in the VTA, but not in the NAC, lowered nicotine self-administration, suggesting that nicotinic receptors in VTA are involved in the reinforcing action of nicotine. This conclusion has been confirmed by subsequent findings, and the nature of the nicotinic receptors has also been elucidated. The authors also reported that DHβE in the VTA had no effect on food or cocaine self-administration, and that lesions to the PPT did not alter nicotine self-administration. Since this initial investigation, the question of whether nicotinic receptors in the VTA are necessary for the reinforcing action of other stimuli, and by which mechanisms, has been extensively explored. Similarly, many groups have further investigated the role of mesopontine cholinergic nuclei in reinforcement. This paper not only contributed in important ways to our understanding of the neurochemical basis of nicotine reinforcement, but was also a key catalyst that gave rise to several research themes central to the neuropharmacology of substance abuse. This article is part of a Special Issue entitled SI:50th Anniversary Issue.
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Nuutinen S, Panula P, Salminen O. Different Hypothalamic Nicotinic α7 Receptor Expression and Response to Low Nicotine Dose in Alcohol-Preferring and Alcohol-Avoiding Rats. Alcohol Clin Exp Res 2016; 40:329-34. [PMID: 26842251 DOI: 10.1111/acer.12960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/08/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND The aim of this study was to examine possible differences in nicotinic acetylcholine receptors and responses in rats with genetic preference or avoidance for alcohol. This was done by using 2 rat lines with high alcohol preference (Alko Alcohol [AA]) or alcohol avoidance (Alko Non-Alcohol [ANA]). METHODS Locomotor activity was measured following nicotine and histamine H3 receptor (H3R) antagonist treatment. In situ hybridization and receptor ligand binding experiments were used in drug-naïve animals to examine the expression of different α nicotinic receptor subunits. RESULTS The AA rats were found to be more sensitive to the stimulatory effect of a low dose of nicotine than ANA rats, which were not significantly activated. Combination of histamine H3R antagonist, JNJ-39220675, and nicotine resulted to similar locomotor activation as nicotine alone. To further understand the mechanism underlying the difference in nicotine response in AA and ANA rats, we studied the expression of α5, α6, and α7 nicotinic receptor subunits in specific brain areas of AA and ANA rats. We found no differences in the expression of α5 nicotinic receptor subunits in the medial habenula and hippocampus or in α6 subunit in the ventral tegmental area and substantia nigra. However, the level of α7 nicotinic receptor subunit mRNA was significantly lower in the tuberomamillary nucleus of posterior hypothalamus of alcohol-preferring AA rats than in alcohol-avoiding ANA rats. Also the hypothalamic [125I-α-bungarotoxin binding was lower in AA rats indicating lower levels of α7 nicotinic receptors. CONCLUSIONS The lower expression and receptor binding of α7 nicotinic receptors in the tuberomamillary nucleus of AA rats suggest a difference in the regulation of brain histamine neurons between the rat lines since the α7 nicotinic receptors are located in histaminergic neurons. Stronger nicotine-induced locomotor response, mediated partially via α7 receptors, and previously described high alcohol consumption in AA rats could be explained by the found difference in tuberomamillary α7 receptor levels.
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Affiliation(s)
- Saara Nuutinen
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland.,Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Pertti Panula
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Outi Salminen
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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Van Skike CE, Maggio SE, Reynolds AR, Casey EM, Bardo MT, Dwoskin LP, Prendergast MA, Nixon K. Critical needs in drug discovery for cessation of alcohol and nicotine polysubstance abuse. Prog Neuropsychopharmacol Biol Psychiatry 2016; 65:269-87. [PMID: 26582145 PMCID: PMC4679525 DOI: 10.1016/j.pnpbp.2015.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 11/10/2015] [Accepted: 11/11/2015] [Indexed: 01/29/2023]
Abstract
Polysubstance abuse of alcohol and nicotine has been overlooked in our understanding of the neurobiology of addiction and especially in the development of novel therapeutics for its treatment. Estimates show that as many as 92% of people with alcohol use disorders also smoke tobacco. The health risks associated with both excessive alcohol consumption and tobacco smoking create an urgent biomedical need for the discovery of effective cessation treatments, as opposed to current approaches that attempt to independently treat each abused agent. The lack of treatment approaches for alcohol and nicotine abuse/dependence mirrors a similar lack of research in the neurobiology of polysubstance abuse. This review discusses three critical needs in medications development for alcohol and nicotine co-abuse: (1) the need for a better understanding of the clinical condition (i.e. alcohol and nicotine polysubstance abuse), (2) the need to better understand how these drugs interact in order to identify new targets for therapeutic development and (3) the need for animal models that better mimic this human condition. Current and emerging treatments available for the cessation of each drug and their mechanisms of action are discussed within this context followed by what is known about the pharmacological interactions of alcohol and nicotine. Much has been and will continue to be gained from studying comorbid alcohol and nicotine exposure.
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Affiliation(s)
- C E Van Skike
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States
| | - S E Maggio
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States
| | - A R Reynolds
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States
| | - E M Casey
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States
| | - M T Bardo
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States; Center for Drug Abuse and Research Translation, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States
| | - L P Dwoskin
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States; Center for Drug Abuse and Research Translation, University of Kentucky, Lexington, KY 40536, United States
| | - M A Prendergast
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States
| | - K Nixon
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States.
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Rahman S, Engleman EA, Bell RL. Recent Advances in Nicotinic Receptor Signaling in Alcohol Abuse and Alcoholism. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 137:183-201. [PMID: 26810002 PMCID: PMC4754113 DOI: 10.1016/bs.pmbts.2015.10.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alcohol is the most commonly abused legal substance and alcoholism is a serious public health problem. It is a leading cause of preventable death in the world. The cellular and molecular mechanisms of alcohol reward and addiction are still not well understood. Emerging evidence indicates that unlike other drugs of abuse, such as nicotine, cocaine, or opioids, alcohol targets numerous channel proteins, receptor molecules, and signaling pathways in the brain. Previously, research has identified brain nicotinic acetylcholine receptors (nAChRs), a heterogeneous family of pentameric ligand-gated cation channels expressed in the mammalian brain, as critical molecular targets for alcohol abuse and dependence. Genetic variations encoding nAChR subunits have been shown to increase the vulnerability to develop alcohol dependence. Here, we review recent insights into the rewarding effects of alcohol, as they pertain to different nAChR subtypes, associated signaling molecules, and pathways that contribute to the molecular mechanisms of alcoholism and/or comorbid brain disorders. Understanding these cellular changes and molecular underpinnings may be useful for the advancement of brain nicotinic-cholinergic mechanisms, and will lead to a better translational and therapeutic outcome for alcoholism and/or comorbid conditions.
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Affiliation(s)
- Shafiqur Rahman
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, South Dakota, USA.
| | - Eric A Engleman
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Richard L Bell
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Scuppa G, Cippitelli A, Toll L, Ciccocioppo R, Ubaldi M. Varenicline decreases nicotine but not alcohol self-administration in genetically selected Marchigian Sardinian alcohol-preferring (msP) rats. Drug Alcohol Depend 2015; 156:126-132. [PMID: 26383997 PMCID: PMC4633345 DOI: 10.1016/j.drugalcdep.2015.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 01/02/2023]
Abstract
BACKGROUND Alcohol and nicotine are largely co-abused. Here, we investigated whether concurrent exposure to both addictive drugs influences each other's consumption and whether varenicline attenuates alcohol consumption in the presence of nicotine. METHODS Marchigian Sardinian alcohol-preferring (msP) rats trained to simultaneously self-administer oral alcohol (10% v/v) and intravenous nicotine (30μg/kg/inf) were used. Additional groups of rats were trained to self-administer either alcohol or nicotine. Further, msP rats were also trained to self-administer nicotine followed by 22-h/day access to alcohol and water in a two bottle free choice paradigm or water alone. The effects of varenicline (0.0, 0.3, 1.0, 3.0mg/kg, p.o.) on alcohol and nicotine consumption were tested. RESULTS In a self-administration paradigm, msP rats showed a significantly high level of alcohol and nicotine intake when the drugs were administered alone. However, when access to both drugs occurred concomitantly, the number of nicotine infusions self-administered was significantly decreased. Nicotine self-administration was markedly reduced by varenicline regardless of whether it was self-administered alone or concurrently with alcohol. In a two bottle choice test, varenicline significantly decreased nicotine self-administration but had no influence on alcohol consumption. CONCLUSION Varenicline is highly efficacious in decreasing nicotine self-administration either alone or in combination with alcohol. However, varenicline failed to influence both operant responding for alcohol and home-cage alcohol drinking in msP animals. Taken together, our findings suggest that the effects of varenicline could be specific to nicotine under conditions where excessive alcohol drinking is facilitated by genetic factors as in msP rats.
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Affiliation(s)
- Giulia Scuppa
- University of Camerino, School of Pharmacy, Pharmacology Unit, Camerino, Italy
| | - Andrea Cippitelli
- Torrey Pines Institute for Molecular Studies, Department of Neuropharmacology, Port St. Lucie, FL, USA
| | - Lawrence Toll
- Torrey Pines Institute for Molecular Studies, Department of Neuropharmacology, Port St. Lucie, FL, USA
| | - Roberto Ciccocioppo
- University of Camerino, School of Pharmacy, Pharmacology Unit, Camerino, Italy
| | - Massimo Ubaldi
- University of Camerino, School of Pharmacy, Pharmacology Unit, Camerino, Italy.
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Perez E, Quijano-Cardé N, De Biasi M. Nicotinic Mechanisms Modulate Ethanol Withdrawal and Modify Time Course and Symptoms Severity of Simultaneous Withdrawal from Alcohol and Nicotine. Neuropsychopharmacology 2015; 40:2327-36. [PMID: 25790020 PMCID: PMC4538347 DOI: 10.1038/npp.2015.80] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 03/11/2015] [Accepted: 03/12/2015] [Indexed: 02/03/2023]
Abstract
Alcohol and nicotine are among the top causes of preventable death in the United States. Unfortunately, people who are dependent on alcohol are more likely to smoke than individuals in the general population. Similarly, smokers are more likely to abuse alcohol. Alcohol and nicotine codependence affects health in many ways and leads to poorer treatment outcomes in subjects who want to quit. This study examined the interaction of alcohol and nicotine during withdrawal and compared abstinence symptoms during withdrawal from one of the two drugs only vs both. Our results indicate that simultaneous withdrawal from alcohol and nicotine produces physical symptoms that are more severe and last longer than those experienced during withdrawal from one of the two drugs alone. In animals experiencing withdrawal after chronic ethanol treatment, acute nicotine exposure was sufficient to prevent abstinence symptoms. Similarly, symptoms were prevented when alcohol was injected acutely in mice undergoing nicotine withdrawal. These experiments provide evidence for the involvement of the nicotinic cholinergic system in alcohol withdrawal. Furthermore, the outcomes of intracranial microinfusions of mecamylamine, a nonselective nicotinic receptor antagonist, highlight a major role for the nicotinic receptors expressed in medial habenula and interpeduncular nucleus during withdrawal. Overall, the data support the notion that modulating the nicotinic cholinergic system might help to maintain long-term abstinence from alcohol.
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Affiliation(s)
- Erika Perez
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | | | - Mariella De Biasi
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA,Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, CRB-217, Philadelphia, PA 19104, USA, Tel: +1 215 898 9579, Fax: +1 215 573 0833, E-mail:
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Early Life Stress, Nicotinic Acetylcholine Receptors and Alcohol Use Disorders. Brain Sci 2015; 5:258-74. [PMID: 26136145 PMCID: PMC4588139 DOI: 10.3390/brainsci5030258] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/11/2015] [Accepted: 06/18/2015] [Indexed: 01/01/2023] Open
Abstract
Stress is a major driving force in alcohol use disorders (AUDs). It influences how much one consumes, craving intensity and whether an abstinent individual will return to harmful alcohol consumption. We are most vulnerable to the effects of stress during early development, and exposure to multiple traumatic early life events dramatically increases the risk for AUDs. However, not everyone exposed to early life stress will develop an AUD. The mechanisms determining whether an individual’s brain adapts and becomes resilient to the effects of stress or succumbs and is unable to cope with stress remain elusive. Emerging evidence suggests that neuroplastic changes in the nucleus accumbens (NAc) following early life stress underlie the development of AUDs. This review discusses the impact of early life stress on NAc structure and function, how these changes affect cholinergic signaling within the mesolimbic reward pathway and the role nicotinic acetylcholine receptors (nAChRs) play in this process. Understanding the neural pathways and mechanism determining stress resilience or susceptibility will improve our ability to identify individuals susceptible to developing AUDs, formulate cognitive interventions to prevent AUDs in susceptible individuals and to elucidate and enhance potential therapeutic targets, such as the nAChRs, for those struggling to overcome an AUD.
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Rahman S, Engleman EA, Bell RL. Nicotinic receptor modulation to treat alcohol and drug dependence. Front Neurosci 2015; 8:426. [PMID: 25642160 PMCID: PMC4295535 DOI: 10.3389/fnins.2014.00426] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 12/04/2014] [Indexed: 01/10/2023] Open
Abstract
Alcohol and drug dependence are serious public health problems worldwide. The prevalence of alcohol and drug dependence in the United States and other parts of the world is significant. Given the limitations in the efficacy of current pharmacotherapies to treat these disorders, research in developing alternative pharmacotherapies continues. Preclinical and clinical evidence thus far has indicated that brain nicotinic acetylcholine receptors (nAChRs) are important pharmacological targets for the development of medications to treat alcohol and drug dependence. The nAChRs are a super family of ligand gated ion channels, and are expressed throughout the brain with twelve neuronal nAChR subunits (α2–α10 and β2–β4) identified. Here, we review preclinical and clinical evidence involving a number of nAChR ligands that target different nAChR subtypes in alcohol and nicotine addiction. The important ligands include cytisine, lobeline, mecamylamine, varenicline, sazetidine A and others that target α4β2* nAChR subtypes as small molecule modulators of the brain nicotinic cholinergic system are also discussed. Taken together, both preclinical and clinical data exist that support nAChR–based ligands as promising therapeutic agents for the treatment of alcohol and drug dependence.
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Affiliation(s)
- Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University Brookings, SD, USA
| | - Eric A Engleman
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine Indianapolis, IN, USA
| | - Richard L Bell
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine Indianapolis, IN, USA
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Rahman S, Engleman EA, Bell RL. Nicotinic receptor modulation to treat alcohol and drug dependence. Front Neurosci 2015. [DOI: https://doi.org/10.3389/fnins.2014.00426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Jupp B, Dalley JW. Convergent pharmacological mechanisms in impulsivity and addiction: insights from rodent models. Br J Pharmacol 2014; 171:4729-66. [PMID: 24866553 PMCID: PMC4209940 DOI: 10.1111/bph.12787] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/02/2014] [Accepted: 05/12/2014] [Indexed: 01/15/2023] Open
Abstract
Research over the last two decades has widely demonstrated that impulsivity, in its various forms, is antecedent to the development of drug addiction and an important behavioural trait underlying the inability of addicts to refrain from continued drug use. Impulsivity describes a variety of rapidly and prematurely expressed behaviours that span several domains from impaired response inhibition to an intolerance of delayed rewards, and is a core symptom of attention deficit hyperactivity disorder (ADHD) and other brain disorders. Various theories have been advanced to explain how impulsivity interacts with addiction both causally and as a consequence of chronic drug abuse; these acknowledge the strong overlaps in neural circuitry and mechanisms between impulsivity and addiction and the seemingly paradoxical treatment of ADHD with stimulant drugs with high abuse potential. Recent years have witnessed unprecedented progress in the elucidation of pharmacological mechanisms underpinning impulsivity. Collectively, this work has significantly improved the prospect for new therapies in ADHD as well as our understanding of the neural mechanisms underlying the shift from recreational drug use to addiction. In this review, we consider the extent to which pharmacological interventions that target impulsive behaviour are also effective in animal models of addiction. We highlight several promising examples of convergence based on empirical findings in rodent-based studies.
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Affiliation(s)
- B Jupp
- Behavioural and Clinical Neuroscience Institute and Department of Psychology, University of CambridgeCambridge, UK
- Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, Australia
| | - J W Dalley
- Behavioural and Clinical Neuroscience Institute and Department of Psychology, University of CambridgeCambridge, UK
- Department of Psychiatry, University of CambridgeCambridge, UK
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Wu J, Gao M, Taylor DH. Neuronal nicotinic acetylcholine receptors are important targets for alcohol reward and dependence. Acta Pharmacol Sin 2014; 35:311-5. [PMID: 24464050 DOI: 10.1038/aps.2013.181] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/18/2013] [Indexed: 01/01/2023] Open
Abstract
Neuronal nicotinic acetylcholine receptors are important targets for alcohol reward and dependence. Alcoholism is a serious public health problem and has been identified as the third major cause of preventable mortality in the world. Worldwide, about 2 billion people consume alcohol, with 76.3 million having diagnosable alcohol use disorders. Alcohol is currently responsible for the death of 4% of adults worldwide (about 2.5 million deaths each year), and this number will be significantly increased by 2020 unless effective action is taken. Alcohol is the most commonly abused substance by humans. Ethanol (EtOH) is the intoxicating agent in alcoholic drinks that can lead to abuse and dependence. Although it has been extensively studied, the mechanisms of alcohol reward and dependence are still poorly understood. The major reason is that, unlike other addictive drugs (eg, morphine, cocaine or nicotine) that have specific molecular targets, EtOH affects much wider neuronal functions. These functions include phospholipid membranes, various ion channels and receptors, synaptic and network functions, and intracellular signaling molecules. The major targets in the brain that mediate EtOH's effects remain unclear. This knowledge gap results in a therapeutic barrier in the treatment of alcoholism. Interestingly, alcohol and nicotine are often co-abused, which suggests that neuronal nicotinic acetylcholine receptors (nAChRs), the molecular targets for nicotine, may also contribute to alcohol's abusive properties. Here, we briefly summarize recent lines of evidence showing how EtOH modulates nAChRs in the mesolimbic pathway, which provides a perspective that nAChRs are important targets mediating alcohol abuse.
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Morganstern I, Lukatskaya O, Moon SH, Guo WR, Shaji J, Karatayev O, Leibowitz SF. Stimulation of nicotine reward and central cholinergic activity in Sprague-Dawley rats exposed perinatally to a fat-rich diet. Psychopharmacology (Berl) 2013; 230:509-24. [PMID: 23836027 PMCID: PMC4006699 DOI: 10.1007/s00213-013-3178-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 06/04/2013] [Indexed: 10/26/2022]
Abstract
RATIONALE While clinical studies show maternal consumption of palatable fat-rich diets during pregnancy to negatively impact the children's behaviors and increase their vulnerability to drug abuse, the precise behavioral and neurochemical mechanisms mediating these phenomena have yet to be examined. OBJECTIVE The study examined in rats whether gestational exposure to a high-fat diet (HFD) can increase the offspring's propensity to use nicotine and whether disturbances in central nicotinic cholinergic signaling accompany this behavioral effect. METHODS Rat offspring exposed perinatally to a HFD or chow diet were characterized in terms of their nicotine self-administration behavior in a series of operant response experiments and the activity of acetylcholinesterase (AChE) and density of nicotinic ACh receptors (nAChRs) in different brain areas. RESULT Perinatal HFD compared to chow exposure increased nicotine-self administration behavior during fixed ratio and dose-response testing and caused an increase in breakpoint using progressive ratio testing, while nicotine seeking in response to nicotine prime-induced reinstatement was reduced. This behavioral change induced by the HFD was associated with a significant reduction in activity of AChE in the midbrain, hypothalamus, and striatum and increased density of β2-nAChRs in the ventral tegmental area and substantia nigra and of α7-nAChRs in the lateral and ventromedial hypothalamus. CONCLUSIONS Perinatal exposure to a HFD increases the vulnerability of the offspring to excessive nicotine use by enhancing its reward potential, and these behavioral changes are accompanied by a stimulation of nicotinic cholinergic signaling in mesostriatal and hypothalamic brain areas important for reinforcement and consummatory behavior.
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Affiliation(s)
- Irene Morganstern
- Laboratory of Behavioral Neurobiology, Rockefeller University, New York, New York 10065, USA
| | - Olga Lukatskaya
- Laboratory of Behavioral Neurobiology, Rockefeller University, New York, New York 10065, USA
| | - Sang-Ho Moon
- Laboratory of Behavioral Neurobiology, Rockefeller University, New York, New York 10065, USA
| | - Wei-Ran Guo
- Laboratory of Behavioral Neurobiology, Rockefeller University, New York, New York 10065, USA
| | - Jane Shaji
- Laboratory of Behavioral Neurobiology, Rockefeller University, New York, New York 10065, USA
| | - Olga Karatayev
- Laboratory of Behavioral Neurobiology, Rockefeller University, New York, New York 10065, USA
| | - Sarah F. Leibowitz
- Laboratory of Behavioral Neurobiology, Rockefeller University, New York, New York 10065, USA
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Haller G, Kapoor M, Budde J, Xuei X, Edenberg H, Nurnberger J, Kramer J, Brooks A, Tischfield J, Almasy L, Agrawal A, Bucholz K, Rice J, Saccone N, Bierut L, Goate A. Rare missense variants in CHRNB3 and CHRNA3 are associated with risk of alcohol and cocaine dependence. Hum Mol Genet 2013; 23:810-9. [PMID: 24057674 DOI: 10.1093/hmg/ddt463] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous findings have demonstrated that variants in nicotinic receptor genes are associated with nicotine, alcohol and cocaine dependence. Because of the substantial comorbidity, it has often been unclear whether a variant is associated with multiple substances or whether the association is actually with a single substance. To investigate the possible contribution of rare variants to the development of substance dependencies other than nicotine dependence, specifically alcohol and cocaine dependence, we undertook pooled sequencing of the coding regions and flanking sequence of CHRNA5, CHRNA3, CHRNB4, CHRNA6 and CHRNB3 in 287 African American and 1028 European American individuals from the Collaborative Study of the Genetics of Alcoholism (COGA). All members of families for whom any individual was sequenced (2504 African Americans and 7318 European Americans) were then genotyped for all variants identified by sequencing. For each gene, we then tested for association using FamSKAT. For European Americans, we find increased DSM-IV cocaine dependence symptoms (FamSKAT P = 2 × 10(-4)) and increased DSM-IV alcohol dependence symptoms (FamSKAT P = 5 × 10(-4)) among carriers of missense variants in CHRNB3. Additionally, one variant (rs149775276; H329Y) shows association with both cocaine dependence symptoms (P = 7.4 × 10(-5), β = 2.04) and alcohol dependence symptoms (P = 2.6 × 10(-4), β = 2.04). For African Americans, we find decreased cocaine dependence symptoms among carriers of missense variants in CHRNA3 (FamSKAT P = 0.005). Replication in an independent sample supports the role of rare variants in CHRNB3 and alcohol dependence (P = 0.006). These are the first results to implicate rare variants in CHRNB3 or CHRNA3 in risk for alcohol dependence or cocaine dependence.
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Sajja RK, Rahman S. Nicotinic receptor partial agonists modulate alcohol deprivation effect in C57BL/6J mice. Pharmacol Biochem Behav 2013. [DOI: https://doi.org/10.1016/j.pbb.2013.07.009] [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: 11/06/2022]
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40
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Suchankova P, Steensland P, Fredriksson I, Engel JA, Jerlhag E. Ghrelin receptor (GHS-R1A) antagonism suppresses both alcohol consumption and the alcohol deprivation effect in rats following long-term voluntary alcohol consumption. PLoS One 2013; 8:e71284. [PMID: 23977009 PMCID: PMC3748070 DOI: 10.1371/journal.pone.0071284] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 07/04/2013] [Indexed: 11/19/2022] Open
Abstract
Alcohol dependence is a heterogeneous disorder where several signalling systems play important roles. Recent studies implicate that the gut-brain hormone ghrelin, an orexigenic peptide, is a potential mediator of alcohol related behaviours. Ghrelin increases whereas a ghrelin receptor (GHS-R1A) antagonist decreases alcohol consumption as well as operant self-administration of alcohol in rodents that have consumed alcohol for twelve weeks. In the present study we aimed at investigating the effect of acute and repeated treatment with the GHS-R1A antagonist JMV2959 on alcohol intake in a group of rats following voluntarily alcohol consumption for two, five and eight months. After approximately ten months of voluntary alcohol consumption the expression of the GHS-R1A gene (Ghsr) as well as the degree of methylation of a CpG island found in Ghsr was examined in reward related brain areas. In a separate group of rats, we examined the effect of the JMV2959 on alcohol relapse using the alcohol deprivation paradigm. Acute JMV2959 treatment was found to decrease alcohol intake and the effect was more pronounced after five, compared to two months of alcohol exposure. In addition, repeated JMV2959 treatment decreased alcohol intake without inducing tolerance or rebound increase in alcohol intake after the treatment. The GHS-R1A antagonist prevented the alcohol deprivation effect in rats. There was a significant down-regulation of the Ghsr expression in the ventral tegmental area (VTA) in high- compared to low-alcohol consuming rats after approximately ten months of voluntary alcohol consumption. Further analysis revealed a negative correlation between Ghsr expression in the VTA and alcohol intake. No differences in methylation degree were found between high- compared to low-alcohol consuming rats. These findings support previous studies showing that the ghrelin signalling system may constitute a potential target for development of novel treatment strategies for alcohol dependence.
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Affiliation(s)
- Petra Suchankova
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Pia Steensland
- Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Stockholm, Sweden
| | - Ida Fredriksson
- Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Stockholm, Sweden
| | - Jörgen A. Engel
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Elisabet Jerlhag
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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Doyon WM, Thomas AM, Ostroumov A, Dong Y, Dani JA. Potential substrates for nicotine and alcohol interactions: a focus on the mesocorticolimbic dopamine system. Biochem Pharmacol 2013; 86:1181-93. [PMID: 23876345 DOI: 10.1016/j.bcp.2013.07.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 07/11/2013] [Accepted: 07/12/2013] [Indexed: 01/13/2023]
Abstract
Epidemiological studies consistently find correlations between nicotine and alcohol use, yet the neural mechanisms underlying their interaction remain largely unknown. Nicotine and alcohol (i.e., ethanol) share many common molecular and cellular targets that provide potential substrates for nicotine-alcohol interactions. These targets for interaction often converge upon the mesocorticolimbic dopamine system, where the link to drug self-administration and reinforcement is well documented. Both nicotine and alcohol activate the mesocorticolimbic dopamine system, producing downstream dopamine signals that promote the drug reinforcement process. While nicotine primarily acts via nicotinic acetylcholine receptors, alcohol acts upon a wider range of receptors and molecular substrates. The complex pharmacological profile of these two drugs generates overlapping responses that ultimately intersect within the mesocorticolimbic dopamine system to promote drug use. Here we will examine overlapping targets between nicotine and alcohol and provide evidence for their interaction. Based on the existing literature, we will also propose some potential targets that have yet to be directly tested. Mechanistic studies that examine nicotine-alcohol interactions would ultimately improve our understanding of the factors that contribute to the associations between nicotine and alcohol use.
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Affiliation(s)
- William M Doyon
- Center on Addiction, Learning, Memory, Baylor College of Medicine, Houston, TX 77030, USA
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Nicotinic receptor partial agonists modulate alcohol deprivation effect in C57BL/6J mice. Pharmacol Biochem Behav 2013; 110:161-7. [PMID: 23872372 DOI: 10.1016/j.pbb.2013.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 07/01/2013] [Accepted: 07/05/2013] [Indexed: 11/22/2022]
Abstract
Relapse is a core feature of alcohol addiction and hinders the pharmacotherapy of alcohol use disorders. Pre-clinical and clinical studies have shown that neuronal nicotinic acetylcholine receptor (nAChR) partial agonists such as cytisine and its derivative, varenicline, reduce alcohol (ethanol) consumption and seeking behavior. However, the effects of these ligands on ethanol relapse are little understood. In the present study, we examined the effects of varenicline and cytisine on alcohol deprivation effect (ADE)--a validated model for relapse-like ethanol drinking in C57BL/6J mice. After habituation to 15% (v/v) ethanol intake using a continuous free-choice procedure, mice were exposed to alternating cycles of ethanol deprivation (5 days) and re-exposure (2 days). At the end of third deprivation cycle, animals received repeated intraperitoneal injections of saline, varenicline (0.5 or 3.0 mg/kg) or cytisine (0.5 or 3.0 mg/kg) and fluid intake was measured post 4 h and 24 h ethanol re-exposure. Repeated ethanol deprivation and re-exposure cycles significantly produced a robust and transient increase in ethanol (ADE). Pretreatment with varenicline (0.5 or 3.0 mg/kg) or cytisine (0.5 or 3.0 mg/kg) significantly reduced the expression of ADE at 4 h and 24 h after ethanol re-exposure. The results from this study indicate that nAChR partial agonists reduce the expression of ADE in mice and further suggest the involvement of nAChR mechanisms in ADE, a relapse-like ethanol drinking behavior.
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Nickell JR, Grinevich VP, Siripurapu KB, Smith AM, Dwoskin LP. Potential therapeutic uses of mecamylamine and its stereoisomers. Pharmacol Biochem Behav 2013; 108:28-43. [PMID: 23603417 PMCID: PMC3690754 DOI: 10.1016/j.pbb.2013.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 04/01/2013] [Accepted: 04/03/2013] [Indexed: 12/17/2022]
Abstract
Mecamylamine (3-methylaminoisocamphane hydrochloride) is a nicotinic parasympathetic ganglionic blocker, originally utilized as a therapeutic agent to treat hypertension. Mecamylamine administration produces several deleterious side effects at therapeutically relevant doses. As such, mecamylamine's use as an antihypertensive agent was phased out, except in severe hypertension. Mecamylamine easily traverses the blood-brain barrier to reach the central nervous system (CNS), where it acts as a nicotinic acetylcholine receptor (nAChR) antagonist, inhibiting all known nAChR subtypes. Since nAChRs play a major role in numerous physiological and pathological processes, it is not surprising that mecamylamine has been evaluated for its potential therapeutic effects in a wide variety of CNS disorders, including addiction. Importantly, mecamylamine produces its therapeutic effects on the CNS at doses 3-fold lower than those used to treat hypertension, which diminishes the probability of peripheral side effects. This review focuses on the pharmacological properties of mecamylamine, the differential effects of its stereoisomers, S(+)- and R(-)-mecamylamine, and the potential for effectiveness in treating CNS disorders, including nicotine and alcohol addiction, mood disorders, cognitive impairment and attention deficit hyperactivity disorder.
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Affiliation(s)
- Justin R Nickell
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.
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Liu L, Zhao-Shea R, McIntosh JM, Tapper AR. Nicotinic acetylcholine receptors containing the α6 subunit contribute to ethanol activation of ventral tegmental area dopaminergic neurons. Biochem Pharmacol 2013; 86:1194-200. [PMID: 23811312 DOI: 10.1016/j.bcp.2013.06.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 06/15/2013] [Accepted: 06/16/2013] [Indexed: 12/17/2022]
Abstract
Nicotine and alcohol are often co-abused suggesting a common mechanism of action may underlie their reinforcing properties. Both drugs acutely increase activity of ventral tegmental area (VTA) dopaminergic (DAergic) neurons, a phenomenon associated with reward behavior. Recent evidence indicates that nicotinic acetylcholine receptors (nAChRs), ligand-gated cation channels activated by ACh and nicotine, may contribute to ethanol-mediated activation of VTA DAergic neurons although the nAChR subtype(s) involved has not been fully elucidated. Here we show that expression and activation of nAChRs containing the α6 subunit contribute to ethanol-induced activation of VTA DAergic neurons. In wild-type (WT) mouse midbrain sections that contain the VTA, ethanol (50 or 100 mM) significantly increased firing frequency of DAergic neurons. In contrast, ethanol did not significantly increase activity of VTA DAergic neurons in mice that do not express CHRNA6, the gene encoding the α6 nAChR subunit (α6 knock-out (KO) mice). Ethanol-induced activity in WT slices was also reduced by pre-application of the α6 subtype-selective nAChR antagonist, α-conotoxin MII[E11A]. When co-applied, ethanol potentiated the response to ACh in WT DAergic neurons; whereas co-application of ACh and ethanol failed to significantly increase activity of DAergic neurons in α6 KO slices. Finally, pre-application of α-conotoxin MII[E11A] in WT slices reduced ethanol potentiation of ACh responses. Together our data indicate that α6-subunit containing nAChRs may contribute to ethanol activation of VTA DAergic neurons. These receptors are predominantly expressed in DAergic neurons and known to be critical for nicotine reinforcement, providing a potential common therapeutic molecular target to reduce nicotine and alcohol co-abuse.
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Affiliation(s)
- Liwang Liu
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
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Hetzler BE, Bauer AM. Interactions between mecamylamine and alcohol in Long-Evans rats: flash-evoked potentials, body temperature, behavior, and blood alcohol concentration. Prog Neuropsychopharmacol Biol Psychiatry 2013; 43:29-39. [PMID: 23228460 DOI: 10.1016/j.pnpbp.2012.11.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 11/20/2012] [Accepted: 11/20/2012] [Indexed: 11/25/2022]
Abstract
Mecamylamine, a noncompetitive antagonist of nicotinic acetylcholine receptors, has many potential clinical applications, including treating alcohol dependency. However, little is known about the combined effects of mecamylamine and alcohol on visual system electrophysiology. We examined the separate and combined effects of mecamylamine (4.0mg/kg, ip) and alcohol (2.0 g/kg, ip) on flash-evoked potentials (FEPs) recorded from the visual cortex (VC) and superior colliculus (SC) of chronically implanted adult male Long-Evans rats. On separate days, either saline or mecamylamine was given 10 min prior to either saline or ethanol. FEPs were recorded 15 and 30 min after the second injection. In the VC, alcohol significantly decreased the amplitudes of components P23, N29, N39, P89, N143, and P237, but increased P46. N63 amplitude was not significantly altered. In contrast, mecamylamine increased the amplitude of P23, P46, and N63, but reduced the amplitude of N29 and P237. The combination of mecamylamine and alcohol resulted in amplitudes very similar to alcohol alone for components P23, N29, N63, P89, N143, and P237. However, mecamylamine pretreatment reduced the effects of alcohol on components N39 and P46. In the SC, FEP component amplitudes were generally decreased by alcohol but not significantly altered by mecamylamine. Mecamylamine pretreatment did not significantly alter the effects of alcohol on SC amplitudes. Latencies of nearly all components in both structures were significantly increased by all drug treatments, with the greatest increase produced by the combination treatment. Hypothermia was also produced by all drug treatments, with the greatest hypothermia (2.25 °C) produced by the combination treatment, most likely accounting for much of the drug-induced increase in latencies. All drug treatments reduced movement during FEP testing, but later in an open field alcohol increased ambulation while mecamylamine reduced movement. Separate groups of experimentally naïve adult male Holtzman albino and Long-Evans hooded rats were given (ip) either alcohol or mecamylamine plus alcohol. Tail vein samples were taken 30 min later. For both rat strains, blood alcohol concentration in the mecamylamine pretreatment group was significantly less at this time interval by about 50-60 mg/dL, suggesting a mechanism whereby mecamylamine can mitigate some of the acute effects of alcohol (e.g., on VC components N39 and P46).
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Affiliation(s)
- Bruce E Hetzler
- Department of Psychology, Lawrence University, 711 E. Boldt Way, Appleton, WI 54911, USA.
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Sajja RK, Rahman S. Cytisine modulates chronic voluntary ethanol consumption and ethanol-induced striatal up-regulation of ΔFosB in mice. Alcohol 2013; 47:299-307. [PMID: 23601929 DOI: 10.1016/j.alcohol.2013.02.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 02/19/2013] [Accepted: 02/19/2013] [Indexed: 01/23/2023]
Abstract
Chronic administration of ethanol induces persistent accumulation of ΔFosB, an important transcription factor, in the midbrain dopamine system. This process underlies the progression to addiction. Previously, we have shown that cytisine, a neuronal nicotinic acetylcholine receptor (nAChR) partial agonist, reduces various ethanol-drinking behaviors and ethanol-induced striatal dopamine function. However, the effects of cytisine on chronic ethanol drinking and ethanol-induced up-regulation of striatal ΔFosB are not known. Therefore, we examined the effects of cytisine on chronic voluntary ethanol consumption and associated striatal ΔFosB up-regulation in C57BL/6J mice using behavioral and biochemical methods. Following the chronic voluntary consumption of 15% (v/v) ethanol under a 24-h two-bottle choice intermittent access (IA; 3 sessions/week) or continuous access (CA; 24 h/d and 7 d/week) paradigm, mice received repeated intraperitoneal injections of saline or cytisine (0.5 or 3.0 mg/kg). Ethanol and water intake were monitored for 24 h post-treatment. Pretreatment with cytisine (0.5 or 1.5 mg/kg) significantly reduced ethanol consumption and preference in both paradigms at 2 h and 24 h post-treatment. The ΔFosB levels in the ventral and dorsal striatum were determined by Western blotting 18-24 h after the last point of ethanol access. In addition, cytisine (0.5 mg/kg) significantly attenuated up-regulation of ΔFosB in the ventral and dorsal striatum following chronic ethanol consumption in IA and CA paradigms. The results indicate that cytisine modulates chronic voluntary ethanol consumption and reduces ethanol-induced up-regulation of striatal ΔFosB. Further, the data suggest a critical role of nAChRs in chronic ethanol-induced neurochemical adaptations associated with ethanol addiction.
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Affiliation(s)
- Ravi Kiran Sajja
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Box 2202C, Avera Health and Science Center (SAV 265), Brookings, SD 57007, USA
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Sajja RK, Rahman S. Cytisine modulates chronic voluntary ethanol consumption and ethanol-induced striatal up-regulation of ΔFosB in mice. Alcohol 2013. [DOI: https://doi.org/10.1016/j.alcohol.2013.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sotomayor-Zárate R, Gysling K, Busto UE, Cassels BK, Tampier L, Quintanilla ME. Varenicline and cytisine: two nicotinic acetylcholine receptor ligands reduce ethanol intake in University of Chile bibulous rats. Psychopharmacology (Berl) 2013; 227:287-98. [PMID: 23344555 DOI: 10.1007/s00213-013-2974-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 12/17/2012] [Indexed: 12/13/2022]
Abstract
RATIONALE Neuronal nicotinic acetylcholine receptors (nAChRs) are pharmacological targets that have recently been implicated in the reinforcing effects of many drugs of abuse, including ethanol. Varenicline and cytisine are nAChR partial agonists in clinical use as smoking cessation aids. However, their efficacies to reduce alcohol consumption have not been fully studied. OBJECTIVES This study aims to compare the effects of varenicline and cytisine on ethanol consumption by rats bred for many generations as high ethanol drinkers (UChB). RESULTS Repeated dosing (0.5 or 1.0 mg/kg/day i.p.) of varenicline or cytisine, for three consecutive days, to male UChB rats pre-exposed to 10 % (v/v) ethanol and water 24 h/day for 4 weeks, significantly reduced alcohol intake and preference of ethanol over water during 1- and 24-h ethanol access periods. This effect was specific for ethanol intake and was not observed for 0.2 % saccharin or water consumption. Varenicline appears to be more effective than cytisine, probably due to its more favorable pharmacokinetic and pharmacodynamic properties. Long-term use of both nAChRs ligands for more than 8-10 days induced tolerance to their effects on ethanol consumption. CONCLUSIONS This preclinical study in UChB rats demonstrated that both varenicline and cytisine reduce alcohol intake, with varenicline producing a greater and longer-lasting reduction than cytisine. However, dose adjustment will have to be considered as a possible way to counter tolerance arising after continued use.
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Affiliation(s)
- Ramón Sotomayor-Zárate
- Departamento de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile.
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Liu L, Hendrickson LM, Guildford MJ, Zhao-Shea R, Gardner PD, Tapper AR. Nicotinic acetylcholine receptors containing the α4 subunit modulate alcohol reward. Biol Psychiatry 2013; 73:738-46. [PMID: 23141806 PMCID: PMC4501776 DOI: 10.1016/j.biopsych.2012.09.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 09/04/2012] [Accepted: 09/20/2012] [Indexed: 02/08/2023]
Abstract
BACKGROUND Nicotine and alcohol are the two most co-abused drugs in the world, suggesting a common mechanism of action might underlie their rewarding properties. Although nicotine elicits reward by activating ventral tegmental area dopaminergic (DAergic) neurons via high-affinity neuronal nicotinic acetylcholine receptors (nAChRs), the mechanism by which alcohol activates these neurons is unclear. METHODS Because most high-affinity nAChRs expressed in ventral tegmental area DAergic neurons contain the α4 subunit, we measured ethanol-induced activation of DAergic neurons in midbrain slices from two complementary mouse models, an α4 knock-out (KO) mouse line and a knock-in line (Leu9'Ala) expressing α4 subunit-containing nAChRs hypersensitive to agonist compared with wild-type (WT). Activation of DAergic neurons by ethanol was analyzed with both biophysical and immunohistochemical approaches in midbrain slices. The ability of alcohol to condition a place preference in each mouse model was also measured. RESULTS At intoxicating concentrations, ethanol activation of DAergic neurons was significantly reduced in α4 KO mice compared with WT. Conversely, in Leu9'Ala mice, DAergic neurons were activated by low ethanol concentrations that did not increase activity of WT neurons. In addition, alcohol potentiated the response to ACh in DAergic neurons, an effect reduced in α4 KO mice. Rewarding alcohol doses failed to condition a place preference in α4 KO mice, paralleling alcohol effects on DAergic neuron activity, whereas a sub-rewarding alcohol dose was sufficient to condition a place preference in Leu9'Ala mice. CONCLUSIONS Together, these data indicate that nAChRs containing the α4 subunit modulate alcohol reward.
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Mahoney MK, Olmstead MC. Neurobiology of an endophenotype: modeling the progression of alcohol addiction in rodents. Curr Opin Neurobiol 2013; 23:607-14. [PMID: 23541596 DOI: 10.1016/j.conb.2013.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 02/25/2013] [Accepted: 03/10/2013] [Indexed: 12/30/2022]
Abstract
Most adults in Western society consume alcohol on a regular basis with few or no negative consequences. However, for certain individuals, alcohol use escalates, leading to uncontrolled drinking bouts, craving, and repeated episodes of relapse. The transition from regulated to uncontrolled and compulsive drinking is a defining feature (i.e. an endophenotype) of alcohol addiction. This behavioral progression can be modeled in rodent paradigms that parallel the diagnostic criteria for addiction in humans. Using these criteria as a framework, this review outlines the neurobiological factors associated with increased vulnerability to excessive, compulsive, and dysregulated alcohol intake in rodents. We conclude by noting gaps in the literature and outline important directions for future research.
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Affiliation(s)
- Megan K Mahoney
- Department of Psychology, Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
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