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Replicated Risk Nicotinic Cholinergic Receptor Genes for Nicotine Dependence. Genes (Basel) 2016; 7:genes7110095. [PMID: 27827986 PMCID: PMC5126781 DOI: 10.3390/genes7110095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/20/2016] [Accepted: 11/02/2016] [Indexed: 01/31/2023] Open
Abstract
It has been hypothesized that the nicotinic acetylcholine receptors (nAChRs) play important roles in nicotine dependence (ND) and influence the number of cigarettes smoked per day (CPD) in smokers. We compiled the associations between nicotinic cholinergic receptor genes (CHRNs) and ND/CPD that were replicated across different studies, reviewed the expression of these risk genes in human/mouse brains, and verified their expression using independent samples of both human and mouse brains. The potential functions of the replicated risk variants were examined using cis-eQTL analysis or predicted using a series of bioinformatics analyses. We found replicated and significant associations for ND/CPD at 19 SNPs in six genes in three genomic regions (CHRNB3-A6, CHRNA5-A3-B4 and CHRNA4). These six risk genes are expressed in at least 18 distinct areas of the human/mouse brain, with verification in our independent human and mouse brain samples. The risk variants might influence the transcription, expression and splicing of the risk genes, alter RNA secondary or protein structure. We conclude that the replicated associations between CHRNB3-A6, CHRNA5-A3-B4,CHRNA4 and ND/CPD are very robust. More research is needed to examine how these genetic variants contribute to the risk for ND/CPD.
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Role of β4* Nicotinic Acetylcholine Receptors in the Habenulo-Interpeduncular Pathway in Nicotine Reinforcement in Mice. Neuropsychopharmacology 2016; 41:1790-802. [PMID: 26585290 PMCID: PMC4869047 DOI: 10.1038/npp.2015.346] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 11/16/2015] [Accepted: 11/16/2015] [Indexed: 11/08/2022]
Abstract
Nicotine exerts its psychopharmacological effects by activating the nicotinic acetylcholine receptor (nAChR), composed of alpha and/or beta subunits, giving rise to a diverse population of receptors with a distinct pharmacology. β4-containing (β4*) nAChRs are located almost exclusively in the habenulo-interpeduncular pathway. We examined the role of β4* nAChRs in the medial habenula (MHb) and the interpeduncular nucleus (IPN) in nicotine reinforcement using behavioral, electrophysiological, and molecular techniques in transgenic mice. Nicotine intravenous self-administration (IVSA) was lower in constitutive β4 knockout (KO) mice at all doses tested (7.5, 15, 30, and 60 μg/kg/infusion) compared with wild-type (WT) mice. In vivo microdialysis showed that β4KO mice have higher extracellular dopamine (DA) levels in the nucleus accumbens than in WT mice, and exhibit a differential sensitivity to nicotine-induced DA outflow. Furthermore, electrophysiological recordings in the ventral tegmental area (VTA) demonstrated that DA neurons of β4KO mice are more sensitive to lower doses of nicotine than that of WT mice. Re-expression of β4* nAChRs in IPN neurons fully restored nicotine IVSA, and attenuated the increased sensitivity of VTA DA neurons to nicotine. These findings suggest that β4* nAChRs in the IPN have a role in maintaining nicotine IVSA.
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A key role for the N/OFQ-NOP receptor system in modulating nicotine taking in a model of nicotine and alcohol co-administration. Sci Rep 2016; 6:26594. [PMID: 27199205 PMCID: PMC4873733 DOI: 10.1038/srep26594] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/05/2016] [Indexed: 11/08/2022] Open
Abstract
Alcohol and nicotine are often co-abused. Although the N/OFQ-NOP receptor system is considered a potential target for development of drug abuse pharmacotherapies, especially for alcoholism, little is known about the role of this system in nicotine dependence. Furthermore, the effect of prior history of nicotine dependence on subsequent nicotine and alcohol taking is understudied. Using an operant co-administration paradigm, in which rats concurrently self-administer nicotine and alcohol, we found that nicotine dependent rats increased nicotine self-administration over time as compared to non-dependent animals, while patterns of alcohol lever pressing did not change between groups. Pretreatment with the potent NOP receptor agonist AT-202 (0.3–3 mg/kg) increased nicotine lever pressing of both dependent and non-dependent groups, whereas the selective antagonist SB612111 (1–10 mg/kg) elicited a clear reduction of nicotine responses, in both dependent and non-dependent rats. In parallel, AT-202 only produced minor changes on alcohol responses and SB612111 reduced alcohol taking at a dose that also reduced locomotor behavior. Results indicate that a history of nicotine dependence affects subsequent nicotine- but not alcohol-maintained responding, and that NOP receptor antagonism, rather than agonism, blocks nicotine self-administration, which strongly suggests a critical role for the endogenous N/OFQ in the modulation of nicotine reinforcement processes.
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Multiple Nicotinic Acetylcholine Receptor Subtypes in the Mouse Amygdala Regulate Affective Behaviors and Response to Social Stress. Neuropsychopharmacology 2016; 41:1579-87. [PMID: 26471256 PMCID: PMC4832019 DOI: 10.1038/npp.2015.316] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/08/2015] [Accepted: 09/14/2015] [Indexed: 12/12/2022]
Abstract
Electrophysiological and neurochemical studies implicate cholinergic signaling in the basolateral amygdala (BLA) in behaviors related to stress. Both animal studies and human clinical trials suggest that drugs that alter nicotinic acetylcholine receptor (nAChR) activity can affect behaviors related to mood and anxiety. Clinical studies also suggest that abnormalities in cholinergic signaling are associated with major depressive disorder, whereas pre-clinical studies have implicated both β2 subunit-containing (β2*) and α7 nAChRs in the effects of nicotine in models of anxiety- and depression-like behaviors. We therefore investigated whether nAChR signaling in the amygdala contributes to stress-mediated behaviors in mice. Local infusion of the non-competitive non-selective nAChR antagonist mecamylamine or viral-mediated downregulation of the β2 or α7 nAChR subunit in the amygdala all induced robust anxiolytic- and antidepressant-like effects in several mouse behavioral models. Further, whereas α7 nAChR subunit knockdown was somewhat more effective at decreasing anxiety-like behavior, only β2 subunit knockdown decreased resilience to social defeat stress and c-fos immunoreactivity in the BLA. In contrast, α7, but not β2, subunit knockdown effectively reversed the effect of increased ACh signaling in a mouse model of depression. These results suggest that signaling through β2* nAChRs is essential for baseline excitability of the BLA, and a decrease in signaling through β2 nAChRs alters anxiety- and depression-like behaviors even in unstressed animals. In contrast, stimulation of α7 nAChRs by acetylcholine may mediate the increased depression-like behaviors observed during the hypercholinergic state observed in depressed individuals.
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Eggan BL, McCallum SE. 18-Methoxycoronaridine acts in the medial habenula to attenuate behavioral and neurochemical sensitization to nicotine. Behav Brain Res 2016; 307:186-93. [PMID: 27059333 DOI: 10.1016/j.bbr.2016.04.008] [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: 02/22/2016] [Revised: 03/31/2016] [Accepted: 04/04/2016] [Indexed: 11/25/2022]
Abstract
Systemic 18-methoxycoronaridine, an alpha3beta4 nicotinic antagonist, slows the rate of induction of behavioral sensitization to nicotine (Glick et al., 1996; 2011). The primary mechanism of action of 18-MC is believed to be the inhibition of α3β4 nicotinic acetylcholine receptors which are densely expressed in the medial habenula and interpeduncular nucleus (Pace et al., 2004; Glick et al., 2012). Recently, these habenular nicotinic receptors and their multiple roles in nicotine aversion and withdrawal have been increasingly emphasized (Antolin-Fontes et al., 2015). Here, we investigated the effects of 18-MC on both behavioral and neurochemical sensitization to nicotine. Daily systemic administration of 18-MC slowed the rate of induction of behavioral sensitization to nicotine but failed to block the expression of a sensitized locomotor response when absent. In contrast, in nicotine sensitized animals, systemic 18-MC significantly reduced the expression of behavioral sensitization. Results from intra-habenular administration of 18-MC paralleled these findings in that the expression of behavioral sensitization was also reduced in sensitized animals. Consistent with its effects on behavioral sensitization, intra-MHb treatment with 18-MC completely abolished sensitized dopamine responses in the nucleus accumbens in nicotine sensitized animals. These results show that α3β4 nicotinic receptors in the MHb contribute to nicotine sensitization, a phenomenon associated with drug craving and relapse.
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Affiliation(s)
- Branden L Eggan
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, United States.
| | - Sarah E McCallum
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, United States.
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Pang X, Liu L, Ngolab J, Zhao-Shea R, McIntosh JM, Gardner PD, Tapper AR. Habenula cholinergic neurons regulate anxiety during nicotine withdrawal via nicotinic acetylcholine receptors. Neuropharmacology 2016; 107:294-304. [PMID: 27020042 DOI: 10.1016/j.neuropharm.2016.03.039] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/07/2016] [Accepted: 03/23/2016] [Indexed: 11/17/2022]
Abstract
Cholinergic neurons in the medial habenula (MHb) modulate anxiety during nicotine withdrawal although the molecular neuroadaptation(s) within the MHb that induce affective behaviors during nicotine cessation is largely unknown. MHb cholinergic neurons are unique in that they robustly express neuronal nicotinic acetylcholine receptors (nAChRs), although their behavioral role as autoreceptors in these neurons has not been described. To test the hypothesis that nAChR signaling in MHb cholinergic neurons could modulate anxiety, we expressed novel "gain of function" nAChR subunits selectively in MHb cholinergic neurons of adult mice. Mice expressing these mutant nAChRs exhibited increased anxiety-like behavior that was alleviated by blockade with a nAChR antagonist. To test the hypothesis that anxiety induced by nicotine withdrawal may be mediated by increased MHb nicotinic receptor signaling, we infused nAChR subtype selective antagonists into the MHb of nicotine naïve and withdrawn mice. While antagonists had little effect on nicotine naïve mice, blocking α4β2 or α6β2, but not α3β4 nAChRs in the MHb alleviated anxiety in mice undergoing nicotine withdrawal. Consistent with behavioral results, there was increased functional expression of nAChRs containing the α6 subunit in MHb neurons that also expressed the α4 subunit. Together, these data indicate that MHb cholinergic neurons regulate nicotine withdrawal-induced anxiety via increased signaling through nicotinic receptors containing the α6 subunit and point toward nAChRs in MHb cholinergic neurons as molecular targets for smoking cessation therapeutics.
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Affiliation(s)
- Xueyan Pang
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Liwang Liu
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Jennifer Ngolab
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Rubing Zhao-Shea
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - J Michael McIntosh
- George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, UT 84108, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA; Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Paul D Gardner
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Andrew R Tapper
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Parikh V, Cole RD, Patel PJ, Poole RL, Gould TJ. Cognitive control deficits during mecamylamine-precipitated withdrawal in mice: Possible links to frontostriatal BDNF imbalance. Neurobiol Learn Mem 2016; 128:110-6. [PMID: 26775017 DOI: 10.1016/j.nlm.2016.01.003] [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: 07/15/2015] [Revised: 12/02/2015] [Accepted: 01/10/2016] [Indexed: 02/06/2023]
Abstract
Nicotine is a major psychoactive and addictive component of tobacco. Although cessation of tobacco use produces various somatic and affective symptoms, withdrawal-related cognitive deficits are considered to be a critical symptom that predict relapse. Therefore, delineating the cognitive mechanisms of nicotine withdrawal may likely provide gainful insights into the neurobiology of nicotine addiction. The present study was designed to examine the effects of nicotine withdrawal induced by mecamylamine, a non-specific nicotinic receptor (nAChR) antagonist, on cognitive control processes in mice using an operant strategy switching task. Brain-derived neurotrophic factor (BDNF) modulates synaptic transmission in frontostriatal circuits, and these circuits are critical for executive functions. Thus, we examined the effects of mecamylamine-precipitated nicotine withdrawal on prefrontal and striatal BDNF protein expression. Mice undergoing precipitated nicotine withdrawal required more trials to attain strategy switching criterion as compared to the controls. Error analysis indicated that impaired performance in these animals was mostly related to their inability to execute the new strategy. The striatal/prefrontal BDNF ratios robustly increased following precipitated nicotine withdrawal. Moreover, higher BDNF ratios were associated with longer task acquisition. Collectively, our findings illustrate that mecamylamine-induced nicotine withdrawal disrupts cognitive control processes and that these changes are possibly linked to perturbations in frontostriatal BDNF signaling.
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Affiliation(s)
- Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, United States.
| | - Robert D Cole
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
| | - Purav J Patel
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
| | - Rachel L Poole
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
| | - Thomas J Gould
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
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Frahm S, Antolin-Fontes B, Görlich A, Zander JF, Ahnert-Hilger G, Ibañez-Tallon I. An essential role of acetylcholine-glutamate synergy at habenular synapses in nicotine dependence. eLife 2015; 4:e11396. [PMID: 26623516 PMCID: PMC4718731 DOI: 10.7554/elife.11396] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/03/2015] [Indexed: 12/24/2022] Open
Abstract
A great deal of interest has been focused recently on the habenula and its critical role in aversion, negative-reward and drug dependence. Using a conditional mouse model of the ACh-synthesizing enzyme choline acetyltransferase (Chat), we report that local elimination of acetylcholine (ACh) in medial habenula (MHb) neurons alters glutamate corelease and presynaptic facilitation. Electron microscopy and immuno-isolation analyses revealed colocalization of ACh and glutamate vesicular transporters in synaptic vesicles (SVs) in the central IPN. Glutamate reuptake in SVs prepared from the IPN was increased by ACh, indicating vesicular synergy. Mice lacking CHAT in habenular neurons were insensitive to nicotine-conditioned reward and withdrawal. These data demonstrate that ACh controls the quantal size and release frequency of glutamate at habenular synapses, and suggest that the synergistic functions of ACh and glutamate may be generally important for modulation of cholinergic circuit function and behavior.
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Affiliation(s)
- Silke Frahm
- Molecular Neurobiology Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Beatriz Antolin-Fontes
- Molecular Neurobiology Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Laboratory of Molecular Biology, The Rockefeller University, New York, United States
| | - Andreas Görlich
- Laboratory of Molecular Biology, The Rockefeller University, New York, United States
| | | | - Gudrun Ahnert-Hilger
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ines Ibañez-Tallon
- Molecular Neurobiology Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Laboratory of Molecular Biology, The Rockefeller University, New York, United States
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Neuroscience of nicotine for addiction medicine: novel targets for smoking cessation medications. PROGRESS IN BRAIN RESEARCH 2015; 223:191-214. [PMID: 26806777 DOI: 10.1016/bs.pbr.2015.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Morbidity and mortality associated with tobacco smoking constitutes a significant burden on healthcare budgets all over the world. Therefore, promoting smoking cessation is an important goal of health professionals and policy makers throughout the world. Nicotine is a major psychoactive component in tobacco that is largely responsible for the widespread addiction to tobacco. A majority of the currently available FDA-approved smoking cessation medications act via neuronal nicotinic receptors. These medications are effective in approximately half of all the smokers, who want to quit and relapse among abstinent smokers continues to be high. In addition to relapse among abstinent smokers, unpleasant effects associated with nicotine withdrawal are a major motivational factor in continued tobacco smoking. Over the last two decades, animal studies have helped in identifying several neural substrates that are involved in nicotine-dependent behaviors including those associated with nicotine withdrawal and relapse to tobacco smoking. In this review, first the role of specific brain regions/circuits that are involved in nicotine dependence will be discussed. Next, the review will describe the role of specific nicotinic receptor subunits in nicotine dependence. Finally, the review will discuss the role of classical neurotransmitters (dopamine, serotonin, noradrenaline, glutamate, and γ-aminobutyric acid) as well as endogenous opioid and endocannabinoid signaling in nicotine dependence. The nicotinic and nonnicotinic neural substrates involved in nicotine-dependent behaviors can serve as possible targets for future smoking cessation medications.
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Shih PY, McIntosh JM, Drenan RM. Nicotine Dependence Reveals Distinct Responses from Neurons and Their Resident Nicotinic Receptors in Medial Habenula. Mol Pharmacol 2015; 88:1035-44. [PMID: 26429939 DOI: 10.1124/mol.115.101444] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/30/2015] [Indexed: 01/22/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are the molecular target of nicotine. nAChRs in the medial habenula (MHb) have recently been shown to play a role in nicotine dependence, but it is not clear which nAChR subtypes or MHb neuron types are most important. To identify MHb nAChRs and/or cell types that play a role in nicotine dependence, we studied these receptors and cells with brain slice electrophysiology using both acute and chronic nicotine application. Cells in the ventroinferior (MHbVI) and ventrolateral MHb (MHbVL) subregions expressed functional nAChRs with different pharmacology. Further, application of nicotine to cells in these subregions led to different action potential firing patterns. The latter result was correlated with a differing ability of nicotine to induce nAChR desensitization. Chronic nicotine caused functional upregulation of nAChRs selectively in MHbVI cells, but did not change nAChR function in MHbVL. Importantly, firing responses were also differentially altered in these subregions following chronic nicotine. MHbVI neurons treated chronically with nicotine exhibited enhanced basal pacemaker firing but a blunted nicotine-induced firing response. MHbVL neurons did not change their firing properties in response to chronic nicotine. Together, these results suggest that acute and chronic nicotine differentially affect nAChR function and output of cells in MHb subregions. Because the MHb extensively innervates the interpeduncular nucleus, an area critical for both affective and somatic signs of withdrawal, these results could reflect some of the neurophysiological changes thought to occur in the MHb to the interpeduncular nucleus circuit in human smokers.
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Affiliation(s)
- Pei-Yu Shih
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (P.-Y.S., R.M.D.) and George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah (J.M.M.)
| | - J Michael McIntosh
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (P.-Y.S., R.M.D.) and George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah (J.M.M.)
| | - Ryan M Drenan
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (P.-Y.S., R.M.D.) and George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah (J.M.M.)
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Zoli M, Pistillo F, Gotti C. Diversity of native nicotinic receptor subtypes in mammalian brain. Neuropharmacology 2015; 96:302-11. [DOI: 10.1016/j.neuropharm.2014.11.003] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/11/2014] [Accepted: 11/08/2014] [Indexed: 01/01/2023]
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62
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Sarginson JE, Killen JD, Lazzeroni LC, Fortmann SP, Ryan HS, Ameli N, Schatzberg AF, Murphy GM. Response to Transdermal Selegiline Smoking Cessation Therapy and Markers in the 15q24 Chromosomal Region. Nicotine Tob Res 2015; 17:1126-33. [PMID: 25572450 PMCID: PMC4627483 DOI: 10.1093/ntr/ntu273] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 12/01/2014] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Current treatments for smoking cessation have limited efficacy. A potential pharmaceutical treatment for smoking cessation is selegiline, a selective and irreversible monoamine oxidase B inhibitor. A few clinical trials have been carried out using selegiline but the results have been mixed. We sought to determine if genetic markers in cholinergic loci in the 15q24 chromosomal region predict response to smoking cessation therapy with selegiline. METHODS We performed an 8-week double-blind, placebo-controlled clinical trial of the selegiline transdermal system in heavy smokers, with follow-up at weeks 25 and 52. Eight single nucleotide polymorphisms (SNPs) in the 15q24 region, which contains the genes for the nicotinic acetylcholine receptor subunits CHRNA5, CHRNA3, and CHRNB4, were investigated for association with treatment response. RESULTS The CHRNB4 promoter SNP rs3813567 was associated with both point prevalence abstinence and post-quit craving. Carriers of the minor C allele treated with selegiline showed lower rates of abstinence and higher levels of craving than selegiline-treated non-carriers, indicating that the rs3813567 C allele adversely affects abstinence in selegiline-treated smokers. This effect was not present among placebo-treated smokers. Selegiline-treated smokers with the CHRNA5 rs680244 GG genotype had lower post-quit craving, and unlike placebo-treated GG-carrying smokers, did not experience a post-quit increase in depressive symptoms. CONCLUSIONS Variants in genes encoding cholinergic receptors affect abstinence, craving and mood in selegiline-treated smokers. Selegiline primarily affects dopamine levels in the brain, but cholinergic input affects nicotine-induced dopaminergic activity. These markers may have value in identifying those likely to respond to selegiline for smoking cessation.
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Affiliation(s)
- Jane E Sarginson
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Joel D Killen
- Department of Medicine, Stanford University School of Medicine, Stanford, CA
| | - Laura C Lazzeroni
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Stephen P Fortmann
- Department of Medicine, Stanford University School of Medicine, Stanford, CA; Center for Health Research, Kaiser Permanente Center for Health Research Northwest, Portland, OR
| | - Heather S Ryan
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Niloufar Ameli
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Alan F Schatzberg
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Greer M Murphy
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA;
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63
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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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64
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Featherstone RE, Siegel SJ. The Role of Nicotine in Schizophrenia. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 124:23-78. [PMID: 26472525 DOI: 10.1016/bs.irn.2015.07.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Schizophrenia is associated with by severe disruptions in thought, cognition, emotion, and behavior. Patients show a marked increase in rates of smoking and nicotine dependence relative to nonaffected individuals, a finding commonly ascribed to the potential ameliorative effects of nicotine on symptom severity and cognitive impairment. Indeed, many studies have demonstrated improvement in patients following the administration of nicotine. Such findings have led to an increased emphasis on the development of therapeutic agents to target the nicotinic system as well as increasing the impetus to understand the genetic basis for nicotinic dysfunction in schizophrenia. The goal of this review article is to provide a critical summary of evidence for the role of the nicotinic system in schizophrenia. The first part will review the role of nicotine in normalization of primary dysfunctions and endophenotypical changes found in schizophrenia. The second part will provide a summary of genetic evidence linking polymorphisms in nicotinic receptor genes to smoking and schizophrenia. The third part will summarize attempts to treat schizophrenia using agents specifically targeting nicotinic and nicotinic receptor subtypes. Although currently available antipsychotic treatments are generally able to manage some aspects of schizophrenia (e.g., positive symptoms) they fail to address several other critically effected aspects of the disease. As such, the search for novel mechanisms to treat this disease is necessary.
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Affiliation(s)
- Robert E Featherstone
- Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Steven J Siegel
- Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Khroyan TV, Yasuda D, Toll L, Polgar WE, Zaveri NT. High affinity α3β4 nicotinic acetylcholine receptor ligands AT-1001 and AT-1012 attenuate cocaine-induced conditioned place preference and behavioral sensitization in mice. Biochem Pharmacol 2015; 97:531-541. [PMID: 26256075 DOI: 10.1016/j.bcp.2015.08.083] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 08/04/2015] [Indexed: 12/18/2022]
Abstract
Cholinergic signaling via the nicotinic acetylcholine receptors (nAChRs) in the mesolimbic circuitry is involved in the rewarding effects of abused drugs such as cocaine and opioids. In mouse studies, nonselective nAChR antagonist mecamylamine blocks cocaine-induced conditioned place preference (CPP) and behavioral sensitization. Among subtype-selective nAChR antagonists, the β2-selective antagonist dihydrobetaerythroidine and α7 antagonist methyllycaconitine (MLA), but not MLA alone prevent behavioral sensitization to cocaine. Since the role of the α3β4 nAChR subtype in the rewarding and behavioral effects of cocaine is unknown, the present study investigated the effect of two potent and selective α3β4 nAChR ligands, AT-1001 and AT-1012, on the acquisition of cocaine-induced CPP and behavioral sensitization in mice. At 5-30mg/kg, cocaine produced robust CPP, whereas behavioral sensitization of locomotor activity was only observed at the higher doses (20-30mg/kg). Pretreatment with AT-1001 (1-10mg/kg) or AT-1012 (3-10mg/kg) blocked CPP induced by 5mg/kg cocaine, but not by 30mg/kg cocaine. Lower doses of AT-1001 (0.3-1mg/kg) and AT-1012 (1-3mg/kg) did not affect the increase in locomotor activity induced by 5 or 30mg/kg cocaine. But AT-1001, at these doses, blocked locomotor sensitization induced by 30mg/kg cocaine. These results indicate that the α3β4 nAChR play a role in the rewarding and behavioral effects of cocaine, and that selective α3β4 nAChR ligands can attenuate cocaine-induced behavioral phenomena. Since the selective α3β4 nAChR functional antagonist AT-1001 has also been shown to block nicotine self-administration in rats, the present results suggest that α3β4 nAChRs may be a target for the treatment of cocaine addiction as well as for cocaine-nicotine comorbid addiction.
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Affiliation(s)
- Taline V Khroyan
- SRI International, 333 Ravenswood Avenue, Menlo Park, CA, United States
| | - Dennis Yasuda
- Astraea Therapeutics, 320 Logue Avenue, Mountain View, CA, United States
| | - Lawrence Toll
- Torrey Pines Institute for Molecular Studies, Jupiter, FL, United States
| | - Willma E Polgar
- SRI International, 333 Ravenswood Avenue, Menlo Park, CA, United States
| | - Nurulain T Zaveri
- Astraea Therapeutics, 320 Logue Avenue, Mountain View, CA, United States.
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Arias HR, Targowska-Duda KM, Feuerbach D, Jozwiak K. The antidepressant-like activity of nicotine, but not of 3-furan-2-yl- N - p -tolyl-acrylamide, is regulated by the nicotinic receptor β4 subunit. Neurochem Int 2015; 87:110-6. [DOI: 10.1016/j.neuint.2015.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/19/2015] [Accepted: 06/10/2015] [Indexed: 01/03/2023]
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Marks MJ, O'Neill HC, Wynalda-Camozzi KM, Ortiz NC, Simmons EE, Short CA, Butt CM, McIntosh JM, Grady SR. Chronic treatment with varenicline changes expression of four nAChR binding sites in mice. Neuropharmacology 2015; 99:142-55. [PMID: 26192545 DOI: 10.1016/j.neuropharm.2015.07.019] [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] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 07/09/2015] [Accepted: 07/16/2015] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Chronic treatment with nicotine is known to increase the α4β2-nAChR sites in brain, to decrease α6β2-nAChR sites and to have minimal effect on α3β4-and α7-nAChR populations. Varenicline is now used as a smoking cessation treatment, with and without continued smoking or nicotine replacement therapy. Varenicline, like nicotine, upregulates the α4β2-nAChR sites; however, it is not known whether varenicline treatment changes expression of the other nAChR subtypes. METHODS Using a mouse model, chronic treatments (10 days) with varenicline (0.12 mg/kg/h) and/or nicotine (1 mg/kg/hr), alone or in combination, were compared for plasma and brain levels of drugs, tolerance to subsequent acute nicotine and expression of four subtypes of nAChR using autoradiography. RESULTS The upregulation of α4β2-nAChR sites elicited by chronic varenicline was very similar to that elicited by chronic nicotine. Treatment with both drugs somewhat increased up-regulation, indicating that these doses were not quite at maximum effect. Similar down-regulation was seen for α6β2-nAChR sites. Varenicline significantly increased both α3β4-and α7-nAChR sites while nicotine had less effect on these sites. The drug combination was similar to varenicline alone for α3β4-nAChR sites, while for α7 sites the drug combination was less effective than varenicline alone. Varenicline had small but significant effects on tolerance to acute nicotine. CONCLUSIONS Effects of varenicline in vivo may not be limited to the α4β2*-nAChR subtype. In addition, smoking cessation treatment with varenicline may not allow receptor numbers to be restored to baseline and may, in addition, change expression of other receptor subtypes.
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Affiliation(s)
- Michael J Marks
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA; Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, USA.
| | - Heidi C O'Neill
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA.
| | | | - Nick C Ortiz
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA.
| | - Emily E Simmons
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA.
| | - Caitlin A Short
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA.
| | | | - J Michael McIntosh
- Departments of Biology and Psychiatry, University of Utah, Salt Lake City, UT, USA.
| | - Sharon R Grady
- Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA.
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Tuan EW, Horti AG, Olson TT, Gao Y, Stockmeier CA, Al-Muhtasib N, Bowman Dalley C, Lewin AE, Wolfe BB, Sahibzada N, Xiao Y, Kellar KJ. AT-1001 Is a Partial Agonist with High Affinity and Selectivity at Human and Rat α3β4 Nicotinic Cholinergic Receptors. Mol Pharmacol 2015; 88:640-9. [PMID: 26162864 DOI: 10.1124/mol.115.099978] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/08/2015] [Indexed: 11/22/2022] Open
Abstract
AT-1001 [N-(2-bromophenyl)-9-methyl-9-azabicyclo[3.3.1] nonan-3-amine] is a high-affinity and highly selective ligand at α3β4 nicotinic cholinergic receptors (nAChRs) that was reported to decrease nicotine self-administration in rats. It was initially reported to be an antagonist at rat α3β4 nAChRs heterologously expressed in HEK293 cells. Here we compared AT-1001 actions at rat and human α3β4 and α4β2 nAChRs similarly expressed in HEK 293 cells. We found that, as originally reported, AT-1001 is highly selective for α3β4 receptors over α4β2 receptors, but its binding selectivity is much greater at human than at rat receptors, because of a higher affinity at human than at rat α3β4 nAChRs. Binding studies in human and rat brain and pineal gland confirmed the selectivity of AT-1001 for α3β4 nAChRs and its higher affinity for human compared with rat receptors. In patch-clamp electrophysiology studies, AT-1001 was a potent partial agonist with 65-70% efficacy at both human and rat α3β4 nAChRs. It was also a less potent and weaker (18%) partial agonist at α4β2 nAChRs. Both α3β4 and α4β2 nAChRs are upregulated by exposure of cells to AT-1001 for 3 days. Similarly, AT-1001 desensitized both receptor subtypes in a concentration-dependent manner, but it was 10 and 30 times more potent to desensitize human α3β4 receptors than rat α3β4 and human α4β2 receptors, respectively. After exposure to AT-1001, the time to recovery from desensitization was longest for the human α3β4 nAChR and shortest for the human α4β2 receptor, suggesting that recovery from desensitization is primarily related to the dissociation of the ligand from the receptor.
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Affiliation(s)
- Edward W Tuan
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Andrew G Horti
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Thao T Olson
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Yongiun Gao
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Craig A Stockmeier
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Nour Al-Muhtasib
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Carrie Bowman Dalley
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Amanda E Lewin
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Barry B Wolfe
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Niaz Sahibzada
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Yingxian Xiao
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
| | - Kenneth J Kellar
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.)
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69
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Ton HT, Smart AE, Aguilar BL, Olson TT, Kellar KJ, Ahern GP. Menthol Enhances the Desensitization of Human α3β4 Nicotinic Acetylcholine Receptors. Mol Pharmacol 2015; 88:256-64. [PMID: 25964258 DOI: 10.1124/mol.115.098285] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/11/2015] [Indexed: 11/22/2022] Open
Abstract
The α3β4 nicotinic acetylcholine receptor (nAChR) subtype is widely expressed in the peripheral and central nervous systems, including in airway sensory nerves. The nAChR subtype transduces the irritant effects of nicotine in tobacco smoke and, in certain brain areas, may be involved in nicotine addiction and/or withdrawal. Menthol, a widely used additive in cigarettes, is a potential analgesic and/or counterirritant at sensory nerves and may also influence nicotine's actions in the brain. We examined menthol's effects on recombinant human α3β4 nAChRs and native nAChRs in mouse sensory neurons. Menthol markedly decreased nAChR activity as assessed by Ca(2+) imaging, (86)Rb(+) efflux, and voltage-clamp measurements. Coapplication of menthol with acetylcholine or nicotine increased desensitization, demonstrated by an increase in the rate and magnitude of the current decay and a reduction of the current integral. These effects increased with agonist concentration. Pretreatment with menthol followed by its washout did not affect agonist-induced desensitization, suggesting that menthol must be present during the application of agonist to augment desensitization. Notably, menthol acted in a voltage-independent manner and reduced the mean open time of single channels without affecting their conductance, arguing against a simple channel-blocking effect. Further, menthol slowed or prevented the recovery of nAChRs from desensitization, indicating that it probably stabilizes a desensitized state. Moreover, menthol at concentrations up to 1 mM did not compete for the orthosteric nAChR binding site labeled by [(3)H]epibatidine. Taken together, these data indicate that menthol promotes desensitization of α3β4 nAChRs by an allosteric action.
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Affiliation(s)
- Hoai T Ton
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Amanda E Smart
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Brittany L Aguilar
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Thao T Olson
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Kenneth J Kellar
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Gerard P Ahern
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
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70
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Perez EE, De Biasi M. Assessment of affective and somatic signs of ethanol withdrawal in C57BL/6J mice using a short-term ethanol treatment. Alcohol 2015; 49:237-43. [PMID: 25817777 DOI: 10.1016/j.alcohol.2015.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/16/2015] [Accepted: 02/17/2015] [Indexed: 11/16/2022]
Abstract
Alcohol is one of the most prevalent addictive substances in the world. Withdrawal symptoms result from abrupt cessation of alcohol consumption in habitual drinkers. The emergence of both affective and physical symptoms produces a state that promotes relapse. Mice provide a preclinical model that could be used to study alcohol dependence and withdrawal while controlling for both genetic and environmental variables. The use of a liquid ethanol diet offers a reliable method for the induction of alcohol dependence in mice, but this approach is impractical when conducting high-throughput pharmacological screens or when comparing multiple strains of genetically engineered mice. The goal of this study was to compare withdrawal-associated behaviors in mice chronically treated with a liquid ethanol diet vs. mice treated with a short-term ethanol treatment that consisted of daily ethanol injections containing the alcohol dehydrogenase inhibitor, 4-methylpyrazole. Twenty-four hours after ethanol treatment, mice were tested in the open field arena, the elevated plus maze, the marble burying test, or for changes in somatic signs during spontaneous ethanol withdrawal. Anxiety-like and compulsive-like behaviors, as well as physical signs, were all significantly elevated in mice undergoing withdrawal, regardless of the route of ethanol administration. Therefore, a short-term ethanol treatment can be utilized as a screening tool for testing genetic and pharmacological agents before investing in a more time-consuming ethanol treatment.
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Affiliation(s)
- E E Perez
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - M De Biasi
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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71
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Zhao-Shea R, DeGroot SR, Liu L, Vallaster M, Pang X, Su Q, Gao G, Rando OJ, Martin GE, George O, Gardner PD, Tapper AR. Increased CRF signalling in a ventral tegmental area-interpeduncular nucleus-medial habenula circuit induces anxiety during nicotine withdrawal. Nat Commun 2015; 6:6770. [PMID: 25898242 PMCID: PMC4405813 DOI: 10.1038/ncomms7770] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 02/25/2015] [Indexed: 02/08/2023] Open
Abstract
Increased anxiety is a prominent withdrawal symptom in abstinent smokers, yet the neuroanatomical and molecular bases underlying it are unclear. Here we show that withdrawal-induced anxiety increases activity of neurons in the interpeduncular intermediate (IPI), a subregion of the interpeduncular nucleus (IPN). IPI activation during nicotine withdrawal was mediated by increased corticotropin releasing factor (CRF) receptor-1 expression and signalling, which modulated glutamatergic input from the medial habenula (MHb). Pharmacological blockade of IPN CRF1 receptors or optogenetic silencing of MHb input reduced IPI activation and alleviated withdrawal-induced anxiety; whereas IPN CRF infusion in mice increased anxiety. We identified a mesointerpeduncular circuit, consisting of ventral tegmental area (VTA) dopaminergic neurons projecting to the IPN, as a potential source of CRF. Knockdown of CRF synthesis in the VTA prevented IPI activation and anxiety during nicotine withdrawal. These data indicate that increased CRF receptor signalling within a VTA-IPN-MHb circuit triggers anxiety during nicotine withdrawal.
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Affiliation(s)
- Rubing Zhao-Shea
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Steven R. DeGroot
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Liwang Liu
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Markus Vallaster
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Xueyan Pang
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Qin Su
- Gene Therapy Center and Department of Microbiology and Physiology Systems, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Guangping Gao
- Gene Therapy Center and Department of Microbiology and Physiology Systems, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Oliver J. Rando
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Gilles E. Martin
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Olivier George
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, 92037
| | - Paul D. Gardner
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Andrew R. Tapper
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
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Xanthos DN, Beiersdorf JW, Thrun A, Ianosi B, Orr-Urtreger A, Huck S, Scholze P. Role of α5-containing nicotinic receptors in neuropathic pain and response to nicotine. Neuropharmacology 2015; 95:37-49. [PMID: 25725336 DOI: 10.1016/j.neuropharm.2015.02.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 02/03/2015] [Accepted: 02/10/2015] [Indexed: 11/26/2022]
Abstract
Nicotinic receptors in the central nervous system (nAChRs) are known to play important roles in pain processing and modulate behavioral responses to analgesic drugs, including nicotine. The presence of the α5-neuronal nicotinic accessory subunit in the nicotinic receptor complex is increasingly understood to modulate reward and aversive states, addiction, and possibly pathological pain. In the current study, using α5-knockout (KO) mice and subunit-specific antibodies, we assess the role of α5-containing neuronal nicotinic receptors in neuropathic pain and in the analgesic response to nicotine. After chronic constriction injury (CCI) or partial sciatic nerve ligation (PSNL), no differences in mechanical, heat, or cold hyperalgesia were found in wild-type (WT) versus α5-KO littermate mice. The number of α5-containing nAChRs was decreased (rather than increased) after CCI in the spinal cord and in the thalamus. Nevertheless, thermal analgesic response to nicotine was marginally reduced in CCI α5-KO mice at 4 days after CCI, but not at later timepoints or after PSNL. Interestingly, upon daily intermittent nicotine injections in unoperated mice, WT animals developed tolerance to nicotine-induced analgesia to a larger extent than α5-KO mice. Our results suggest that α5-containing nAChRs mediate analgesic tolerance to nicotine but do not play a major role in neuropathic pain.
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Affiliation(s)
- Dimitris N Xanthos
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Austria.
| | - Johannes W Beiersdorf
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Austria
| | - Ariane Thrun
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Austria
| | - Bogdan Ianosi
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Austria
| | - Avi Orr-Urtreger
- The Genetic Institute, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; The Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Sigismund Huck
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Austria
| | - Petra Scholze
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Austria.
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Brunzell DH, Stafford AM, Dixon CI. Nicotinic receptor contributions to smoking: insights from human studies and animal models. CURRENT ADDICTION REPORTS 2015; 2:33-46. [PMID: 26301171 DOI: 10.1007/s40429-015-0042-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It is becoming increasingly evident that a variety of factors contribute to smoking behavior. Nicotine is a constituent of tobacco smoke that exerts its psychoactive effects via binding to nicotinic acetylcholine receptors (nAChRs) in brain. Human genetic studies have identified polymorphisms in nAChR genes, which predict vulnerability to risk for tobacco dependence. In vitro studies and animal models have identified the functional relevance of specific polymorphisms. Together with animal behavioral models, which parse behaviors believed to contribute to tobacco use in humans, these studies demonstrate that nicotine action at a diversity of nAChRs is important for expression of independent behavioral phenotypes, which support smoking behavior.
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Affiliation(s)
- Darlene H Brunzell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA
| | - Alexandra M Stafford
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA
| | - Claire I Dixon
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA
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Differential expression of the beta4 neuronal nicotinic receptor subunit affects tolerance development and nicotinic binding sites following chronic nicotine treatment. Pharmacol Biochem Behav 2015; 130:1-8. [PMID: 25560939 DOI: 10.1016/j.pbb.2014.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/06/2014] [Accepted: 12/27/2014] [Indexed: 11/22/2022]
Abstract
The role of neuronal nicotinic acetylcholine receptors (nAChR) containing the β4 subunit in tolerance development and nicotinic binding site levels following chronic nicotine treatment was investigated. Mice differing in expression of the β4-nAChR subunit [wild-type (β4(++)), heterozygote (β4(+-)) and null mutant (β4(--))] were chronically treated for 10 days with nicotine (0, 0.5, 1.0, 2.0 or 4.0mg/kg/h) by constant intravenous infusion. Chronic nicotine treatment elicited dose-dependent tolerance development. β4(--) mice developed significantly more tolerance than either β4(++) or β4(+-) mice which was most evident following treatment with 4.0mg/kg/h nicotine. Subsets of [(125)I]-epibatidine binding were measured in several brain regions. Deletion of the β4 subunit had little effect on initial levels of cytisine-sensitive [(125)I]-epibatidine binding (primarily α4β2-nAChR sites) or their response (generally increased binding) to chronic nicotine treatment. In contrast, β4 gene-dose-dependent decreases in expression 5IA-85380 resistant [(125)I]-epibatidine binding sites (primarily β4*-nAChR) were observed. While these β4*-nAChR sites were generally resistant to regulation by chronic nicotine treatment, significant increases in binding were noted for habenula and hindbrain. Comparison of previously published tolerance development in β2(--) mice (less tolerance) to that of β4(--) mice (more tolerance) supports a differential role for these receptor subtypes in regulating tolerance following chronic nicotine treatment.
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75
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Lee H, Kang MS, Chung JM, Noh J. Repeated nicotine exposure in adolescent rats: Reduction of medial habenular activity and augmentation of nicotine preference. Physiol Behav 2015; 138:345-50. [DOI: 10.1016/j.physbeh.2014.11.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 11/09/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
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Abstract
An aversive abstinence syndrome manifests 4-24 h following cessation of chronic use of nicotine-containing products. Symptoms peak on approximately the 3rd day and taper off over the course of the following 3-4 weeks. While the severity of withdrawal symptoms is largely determined by how nicotine is consumed, certain short nucleotide polymorphisms (SNPs) have been shown to predispose individuals to consume larger amounts of nicotine more frequently--as well as to more severe symptoms of withdrawal when trying to quit. Additionally, rodent behavioral models and transgenic mouse models have revealed that specific nicotinic acetylcholine receptor (nAChR) subunits, cellular components, and neuronal circuits are critical to the expression of withdrawal symptoms. Consequently, by continuing to map neuronal circuits and nAChR subpopulations that underlie the nicotine withdrawal syndrome--and by continuing to enumerate genes that predispose carriers to nicotine addiction and exacerbated withdrawal symptoms--it will be possible to pursue personalized therapeutics that more effectively treat nicotine addiction.
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Affiliation(s)
- Ian McLaughlin
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Contribution of Variants in CHRNA5/A3/B4 Gene Cluster on Chromosome 15 to Tobacco Smoking: From Genetic Association to Mechanism. Mol Neurobiol 2014; 53:472-484. [PMID: 25471942 DOI: 10.1007/s12035-014-8997-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/11/2014] [Indexed: 10/24/2022]
Abstract
Cigarette smoking is the major cause of preventable death and morbidity throughout the world. Many compounds are present in tobacco, but nicotine is the primary addictive one. Nicotine exerts its physiological and pharmacological roles in the brain through neuronal nicotinic acetylcholine receptors (nAChRs), which are ligand-gated ion channels consisting of five membrane-spanning subunits that can modulate the release of neurotransmitters, such as dopamine, glutamate, and GABA and mediate fast signal transmission at synapses. Considering that there are 12 nAChR subunits, it is highly likely that subunits other than α4 and β2, which have been intensively investigated, also are involved in nicotine addiction. Consistent with this hypothesis, a number of genome-wide association studies (GWAS) and subsequent candidate gene-based associated studies investigating the genetic variants associated with nicotine dependence (ND) and smoking-related phenotypes have shed light on the CHRNA5/A3/B4 gene cluster on chromosome 15, which encodes the α5, α3, and β4 nAChR subunits, respectively. These studies demonstrate two groups of risk variants in this region. The first one is marked by single nucleotide polymorphism (SNP) rs16969968 in exon 5 of CHRNA5, which changes an aspartic acid residue into asparagine at position 398 (D398N) of the α5 subunit protein sequence, and it is tightly linked SNP rs1051730 in CHRNA3. The second one is SNP rs578776 in the 3'-untranslated region (UTR) of CHRNA3, which has a low correlation with rs16969968. Although the detailed molecular mechanisms underlying these associations remain to be further elucidated, recent findings have shown that α5* (where "*" indicates the presence of additional subunits) nAChRs located in the medial habenulo-interpeduncular nucleus (mHb-IPN) are involved in the control of nicotine self-administration in rodents. Disruption of α5* nAChR signaling diminishes the aversive effects of nicotine on the mHb-IPN pathway and thereby permits more nicotine consumption. To gain a better understanding of the function of the highly significant genetic variants identified in this region in controlling smoking-related behaviors, in this communication, we provide an up-to-date review of the progress of studies focusing on the CHRNA5/A3/B4 gene cluster and its role in ND.
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Antolin-Fontes B, Ables JL, Görlich A, Ibañez-Tallon I. The habenulo-interpeduncular pathway in nicotine aversion and withdrawal. Neuropharmacology 2014; 96:213-22. [PMID: 25476971 DOI: 10.1016/j.neuropharm.2014.11.019] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/31/2014] [Accepted: 11/21/2014] [Indexed: 12/23/2022]
Abstract
Progress has been made over the last decade in our understanding of the brain areas and circuits involved in nicotine reward and withdrawal, leading to models of addiction that assign different addictive behaviors to distinct, yet overlapping, neural circuits (Koob and Volkow, 2010; Lobo and Nestler, 2011; Tuesta et al., 2011; Volkow et al., 2011). Recently the habenulo-interpeduncular (Hb-IPN) midbrain pathway has re-emerged as a new critical crossroad that influences the brain response to nicotine. This brain area is particularly enriched in nicotinic acetylcholine receptor (nAChR) subunits α5, α3 and β4 encoded by the CHRNA5-A3-B4 gene cluster, which has been associated with vulnerability to tobacco dependence in human genetics studies. This finding, together with studies in mice involving deletion and replacement of nAChR subunits, and investigations of the circuitry, cell types and electrophysiological properties, have begun to identify the molecular mechanisms that take place in the MHb-IPN which underlie critical aspects of nicotine dependence. In the current review we describe the anatomical and functional connections of the MHb-IPN system, as well as the contribution of specific nAChRs subtypes in nicotine-mediated behaviors. Finally, we discuss the specific electrophysiological properties of MHb-IPN neuronal populations and how nicotine exposure alters their cellular physiology, highlighting the unique role of the MHb-IPN in the context of nicotine aversion and withdrawal. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.
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Affiliation(s)
- Beatriz Antolin-Fontes
- Laboratory of Molecular Biology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, NY 10065, New York, USA
| | - Jessica L Ables
- Laboratory of Molecular Biology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, NY 10065, New York, USA
| | - Andreas Görlich
- Laboratory of Molecular Biology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, NY 10065, New York, USA
| | - Inés Ibañez-Tallon
- Laboratory of Molecular Biology and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, NY 10065, New York, USA.
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Arias HR, Feuerbach D, Targowska-Duda K, Kaczor AA, Poso A, Jozwiak K. Pharmacological and molecular studies on the interaction of varenicline with different nicotinic acetylcholine receptor subtypes. Potential mechanism underlying partial agonism at human α4β2 and α3β4 subtypes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:731-41. [PMID: 25475645 DOI: 10.1016/j.bbamem.2014.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/29/2014] [Accepted: 11/06/2014] [Indexed: 02/06/2023]
Abstract
To determine the structural components underlying differences in affinity, potency, and selectivity of varenicline for several human (h) nicotinic acetylcholine receptors (nAChRs), functional and structural experiments were performed. The Ca2+ influx results established that: (a) varenicline activates (μM range) nAChR subtypes with the following rank sequence: hα7>hα4β4>hα4β2>hα3β4>>>hα1β1γδ; (b) varenicline binds to nAChR subtypes with the following affinity order (nM range): hα4β2~hα4β4>hα3β4>hα7>>>Torpedo α1β1γδ. The molecular docking results indicating that more hydrogen bond interactions are apparent for α4-containing nAChRs in comparison to other nAChRs may explain the observed higher affinity; and that (c) varenicline is a full agonist at hα7 (101%) and hα4β4 (93%), and a partial agonist at hα4β2 (20%) and hα3β4 (45%), relative to (±)-epibatidine. The allosteric sites found at the extracellular domain (EXD) of hα3β4 and hα4β2 nAChRs could explain the partial agonistic activity of varenicline on these nAChR subtypes. Molecular dynamics simulations show that the interaction of varenicline to each allosteric site decreases the capping of Loop C at the hα4β2 nAChR, suggesting that these allosteric interactions limit the initial step in the gating process. In conclusion, we propose that in addition to hα4β2 nAChRs, hα4β4 nAChRs can be considered as potential targets for the clinical activity of varenicline, and that the allosteric interactions at the hα3β4- and hα4β2-EXDs are alternative mechanisms underlying partial agonism at these nAChRs.
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Affiliation(s)
- Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA, USA.
| | - Dominik Feuerbach
- Neuroscience Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Katarzyna Targowska-Duda
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, Lublin, Poland
| | - Agnieszka A Kaczor
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Medical University of Lublin, Lublin, Poland
| | - Antti Poso
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Krzysztof Jozwiak
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, Lublin, Poland
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Jackson KJ, Muldoon PP, De Biasi M, Damaj MI. New mechanisms and perspectives in nicotine withdrawal. Neuropharmacology 2014; 96:223-34. [PMID: 25433149 DOI: 10.1016/j.neuropharm.2014.11.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/21/2014] [Accepted: 11/17/2014] [Indexed: 02/08/2023]
Abstract
Diseases associated with tobacco use constitute a major health problem worldwide. Upon cessation of tobacco use, an unpleasant withdrawal syndrome occurs in dependent individuals. Avoidance of the negative state produced by nicotine withdrawal represents a motivational component that promotes continued tobacco use and relapse after smoking cessation. With the modest success rate of currently available smoking cessation therapies, understanding mechanisms involved in the nicotine withdrawal syndrome are crucial for developing successful treatments. Animal models provide a useful tool for examining neuroadaptative mechanisms and factors influencing nicotine withdrawal, including sex, age, and genetic factors. Such research has also identified an important role for nicotinic receptor subtypes in different aspects of the nicotine withdrawal syndrome (e.g., physical vs. affective signs). In addition to nicotinic receptors, the opioid and endocannabinoid systems, various signal transduction pathways, neurotransmitters, and neuropeptides have been implicated in the nicotine withdrawal syndrome. Animal studies have informed human studies of genetic variants and potential targets for smoking cessation therapies. Overall, the available literature indicates that the nicotine withdrawal syndrome is complex, and involves a range of neurobiological mechanisms. As research in nicotine withdrawal progresses, new pharmacological options for smokers attempting to quit can be identified, and treatments with fewer side effects that are better tailored to the unique characteristics of patients may become available. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.
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Affiliation(s)
- K J Jackson
- Department of Psychiatry, Virginia Commonwealth University, 800 E. Leigh St., Richmond, VA 23219, USA
| | - P P Muldoon
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1220 E. Marshall St., Richmond, VA 23219, USA
| | - M De Biasi
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - M I Damaj
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1220 E. Marshall St., Richmond, VA 23219, USA.
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81
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Suter MA, Mastrobattista J, Sachs M, Aagaard K. Is there evidence for potential harm of electronic cigarette use in pregnancy? ACTA ACUST UNITED AC 2014; 103:186-95. [PMID: 25366492 DOI: 10.1002/bdra.23333] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Use of electronic cigarettes (e-cigarettes) and other nicotine containing products is increasing among women of reproductive age. The short- and long-term effects of these products on both mother and fetus are unknown. METHODS Because e-cigarettes are nicotine delivery systems, we sought to conduct a comprehensive review of the effects of nicotine on the fetus. RESULTS In utero nicotine exposure in animal models is associated with adverse effects for the offspring lung, cardiovascular system and brain. In the lung, this included reduced surface area, weight, and volume, as well as emphysema-like lesions. In adulthood, exposed offspring demonstrate elevated blood pressure and increased perivascular adipose tissue. In the brain, exposure alters offspring serotonergic, dopaminergic, and norepinephrine networks, which in turn are associated with behavioral and cognitive impairments. We also review current data on the lack of efficacy of nicotine replacement therapy in pregnant women, and highlight different nicotine containing products such as snuff, snus, and hookah. CONCLUSION We conclude that no amount of nicotine is known to be safe during pregnancy, and studies specifically addressing this risk are crucial and an imminent public health issue.
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Affiliation(s)
- Melissa A Suter
- Baylor College of Medicine, Obstetrics & Gynecology, Division of Maternal-Fetal Medicine, Houston, Texas
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Jozwiak K, Targowska-Duda KM, Kaczor AA, Kozak J, Ligeza A, Szacon E, Wrobel TM, Budzynska B, Biala G, Fornal E, Poso A, Wainer IW, Matosiuk D. Synthesis, in vitro and in vivo studies, and molecular modeling of N-alkylated dextromethorphan derivatives as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptor. Bioorg Med Chem 2014; 22:6846-56. [PMID: 25464883 DOI: 10.1016/j.bmc.2014.10.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 10/03/2014] [Accepted: 10/24/2014] [Indexed: 11/26/2022]
Abstract
9 N-alkylated derivatives of dextromethorphan are synthesized and studied as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptors (nAChRs). In vitro activity towards α3β4 nicotinic acetylcholine receptor is determined using a patch-clamp technique and is in the micromolar range. Homology modeling, molecular docking and molecular dynamics of ligand-receptor complexes in POPC membrane are used to find the mode of interactions of N-alkylated dextromethorphan derivatives with α3β4 nAChR. The compounds, similarly as dextromethorphan, interact with the middle portion of α3β4 nAChR ion channel. Finally, behavioral tests confirmed potential application of the studied compounds for the treatment of addiction.
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Affiliation(s)
- Krzysztof Jozwiak
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, 4a Chodzki St., PL-20093 Lublin, Poland
| | - Katarzyna M Targowska-Duda
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, 4a Chodzki St., PL-20093 Lublin, Poland
| | - Agnieszka A Kaczor
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical Analytics, 4a Chodzki St., PL-20093 Lublin, Poland; School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, PO Box 1627, FI-70211 Kuopio, Finland
| | - Joanna Kozak
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, 4a Chodzki St., PL-20093 Lublin, Poland; Department of Anatomy, Medical University of Lublin, 4 Jaczewskiego St., PL-20090 Lublin, Poland
| | - Agnieszka Ligeza
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical Analytics, 4a Chodzki St., PL-20093 Lublin, Poland
| | - Elzbieta Szacon
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical Analytics, 4a Chodzki St., PL-20093 Lublin, Poland
| | - Tomasz M Wrobel
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical Analytics, 4a Chodzki St., PL-20093 Lublin, Poland
| | - Barbara Budzynska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, 4a Chodzki St., PL-20093 Lublin, Poland
| | - Grazyna Biala
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, 4a Chodzki St., PL-20093 Lublin, Poland
| | - Emilia Fornal
- Department of Chemistry, Catholic University of Lublin, al. Krasnicka 102, PL-20718 Lublin, Poland
| | - Antti Poso
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, PO Box 1627, FI-70211 Kuopio, Finland
| | - Irving W Wainer
- Laboratory of Clinical Investigation, Division of Intramural Research Programs, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Dariusz Matosiuk
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Faculty of Pharmacy with Division of Medical Analytics, 4a Chodzki St., PL-20093 Lublin, Poland.
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Differential expression and function of nicotinic acetylcholine receptors in subdivisions of medial habenula. J Neurosci 2014; 34:9789-802. [PMID: 25031416 DOI: 10.1523/jneurosci.0476-14.2014] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neuronal nAChRs in the medial habenula (MHb) to the interpeduncular nucleus (IPN) pathway are key mediators of nicotine's aversive properties. In this paper, we report new details regarding nAChR anatomical localization and function in MHb and IPN. A new group of knock-in mice were created that each expresses a single nAChR subunit fused to GFP, allowing high-resolution mapping. We find that α3 and β4 nAChR subunit levels are strong throughout the ventral MHb (MHbV). In contrast, α6, β2, β3, and α4 subunits are selectively found in some, but not all, areas of MHbV. All subunits were found in both ChAT-positive and ChAT-negative cells in MHbV. Next, we examined functional properties of neurons in the lateral and central part of MHbV (MHbVL and MHbVC) using brain slice patch-clamp recordings. MHbVL neurons were more excitable than MHbVC neurons, and they also responded more strongly to puffs of nicotine. In addition, we studied firing responses of MHbVL and MHbVC neurons in response to bath-applied nicotine. Cells in MHbVL, but not those in MHbVC, increased their firing substantially in response to 1 μm nicotine. Additionally, MHbVL neurons from mice that underwent withdrawal from chronic nicotine were less responsive to nicotine application compared with mice withdrawn from chronic saline. Last, we characterized rostral and dorsomedial IPN neurons that receive input from MHbVL axons. Together, our data provide new details regarding neurophysiology and nAChR localization and function in cells within the MHbV.
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84
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Zaveri NT, Bertrand S, Yasuda D, Bertrand D. Functional characterization of AT-1001, an α3β4 nicotinic acetylcholine receptor ligand, at human α3β4 and α4β2 nAChR. Nicotine Tob Res 2014; 17:361-7. [PMID: 25180076 DOI: 10.1093/ntr/ntu170] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Genome-wide association studies linking the α3, β4, and α5 nicotinic acetylcholine receptor (nAChR) subunits to nicotine dependence suggest that α3β4* nAChR may be targets for smoking cessation pharmacotherapies. We previously reported that AT-1001, a selective α3β4* nAChR ligand binds with high affinity to rat α3β4 and human α3β4α5 nAChR, antagonizes epibatidine-induced activation of rat α3β4 nAChR in HEK cells and potently inhibits nicotine self-administration in rats. METHODS Two-electrode voltage clamp was used for functional characterization of AT-1001 at recombinant human α3β4 and α4β2 nAChR expressed in Xenopus oocytes. RESULTS Concentration-response curves show that AT-1001 is a partial agonist at human α3β4 nAChR, evoking up to 35% of the maximal acetylcholine (ACh) response (50% effective concentration [EC50] = 0.37 μM). AT-1001 showed very little agonist activity at the α4β2 nAChR, evoking only 6% of the ACh response (EC50 = 1.5 μM). Pre- and co-application of various concentrations of AT-1001 with 50 μM ACh revealed a complex pattern of activation-inhibition by AT-1001 at α3β4 nAChR, which was best fitted by a 2-site equation. At α4β2 nAChR, co-exposure of AT-1001 with ACh only showed inhibition of ACh current with a shallower curve. CONCLUSIONS AT-1001 is a partial agonist at the human α3β4 nAChR and causes desensitization at concentrations at which it evokes an inward current, resulting in an overall functional antagonism of α3β4 nAChR. AT-1001 does not significantly activate or desensitize α4β2 nAChR at the same concentrations as at the α3β4 nAChR, but does inhibit ACh responses at α4β2 nAChR at higher concentrations. A combination of these mechanisms may underlie the inhibition of nicotine self-administration by AT-1001, suggesting that AT-1001 and compounds from this class may have clinical potential for smoking cessation pharmacotherapy.
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Varani AP, Moutinho Machado L, Balerio GN. Baclofen prevented the changes in c-Fos and brain-derived neutrophic factor expressions during mecamylamine-precipitated nicotine withdrawal in mice. Synapse 2014; 68:508-17. [DOI: 10.1002/syn.21763] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/12/2014] [Accepted: 06/30/2014] [Indexed: 12/13/2022]
Affiliation(s)
- Andrés P. Varani
- Instituto de Investigaciones Farmacológicas (UBA-CONICET); Junín 956, 5° piso, (C1113AAD) Buenos Aires Argentina
| | - Lirane Moutinho Machado
- Instituto de Investigaciones Farmacológicas (UBA-CONICET); Junín 956, 5° piso, (C1113AAD) Buenos Aires Argentina
| | - Graciela N. Balerio
- Instituto de Investigaciones Farmacológicas (UBA-CONICET); Junín 956, 5° piso, (C1113AAD) Buenos Aires Argentina
- Cátedra de Farmacología; Facultad de Farmacia y Bioquímica; Universidad de Buenos Aires; Junín 956 5° Piso, (C1113AAD) Buenos Aires Argentina
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Stoker AK, Marks MJ, Markou A. Null mutation of the β2 nicotinic acetylcholine receptor subunit attenuates nicotine withdrawal-induced anhedonia in mice. Eur J Pharmacol 2014; 753:146-50. [PMID: 25107281 DOI: 10.1016/j.ejphar.2014.05.062] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/17/2014] [Accepted: 05/27/2014] [Indexed: 11/25/2022]
Abstract
The anhedonic signs of nicotine withdrawal are predictive of smoking relapse rates in humans. Identification of the neurobiological substrates that mediate anhedonia will provide insights into the genetic variations that underlie individual responses to smoking cessation and relapse. The present study assessed the role of β2 nicotinic acetylcholine receptor (nACh receptor) subunits in nicotine withdrawal-induced anhedonia using β2 nACh receptor subunit knockout (β2(-/-)) and wildtype (β2(+/+)) mice. Anhedonia was assessed with brain reward thresholds, defined as the current intensity that supports operant behavior in the discrete-trial current-intensity intracranial self-stimulation procedure. Nicotine was delivered chronically through osmotic minipumps for 28 days (40 mg/kg/day, base), and withdrawal was induced by either administering the broad-spectrum nicotinic receptor antagonist mecamylamine (i.e., antagonist-precipitated withdrawal) in mice chronically treated with nicotine or terminating chronic nicotine administration (i.e., spontaneous withdrawal). Mecamylamine (6 mg/kg, salt) significantly elevated brain reward thresholds in nicotine-treated β2(+/+) mice compared with saline-treated β2(+/+) mice and nicotine-treated β2(-/-) mice. Spontaneous nicotine withdrawal similarly resulted in significant elevations in thresholds in nicotine-withdrawing β2(+/+) mice compared with saline-treated β2(+/+) and nicotine-treated β2(-/-) mice, which remained at baseline levels. These results showed that precipitated and spontaneous nicotine withdrawal-induced anhedonia was attenuated in β2(-/-) mice. The reduced expression of anhedonic signs during nicotine withdrawal in β2(-/-) mice may have resulted from the lack of neuroadaptations in β2 nACh receptor subunit expression and function that may have occurred during either nicotine exposure or nicotine withdrawal in wildtype mice. In conclusion, individuals with genetic variations that result in diminished function of the β2 nACh receptor subunit may experience less anhedonia during nicotine withdrawal, which may facilitate smoking cessation.
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Affiliation(s)
- Astrid K Stoker
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA 92093-0603, USA
| | - Michael J Marks
- Institute for Behavioral Genetics and Department of Psychology and Neuroscience, 447 UCB, University of Colorado, Boulder, CO, USA
| | - Athina Markou
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA 92093-0603, USA.
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Roni MA, Rahman S. The effects of lobeline on nicotine withdrawal-induced depression-like behavior in mice. Psychopharmacology (Berl) 2014; 231:2989-98. [PMID: 24682499 DOI: 10.1007/s00213-014-3472-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/27/2014] [Indexed: 01/12/2023]
Abstract
RATIONALE Evidence suggests that neuronal nicotinic acetylcholine receptor (nAChR) ligand lobeline has antidepressant-like properties. OBJECTIVES The present study investigated the effects of lobeline on nicotine withdrawal-induced depression-like behavior. METHODS Adult C57BL/6J mice were exposed to nicotine (200 μg/ml) in drinking solution for 3 weeks. During withdrawal, depression-like behavior was measured by the forced swim test (FST). We also determined norepinephrine (NE) levels in the prefrontal cortex (PFC) and hippocampus during nicotine withdrawal. Furthermore, we determined the effects of repeated treatment with lobeline or a selective α4β2 nAChR ligand 3-(pyridine-3́-yl)-cytisine on brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP-responsive element binding (p-CREB) protein expression in the hippocampus. RESULTS Withdrawal from chronic nicotine increased immobility time in the FST, a measure for depression-like behavior. Pretreatment with lobeline significantly decreased immobility time during nicotine withdrawal. In addition, pretreatment with lobeline attenuated nicotine withdrawal-induced increased NE levels in the PFC and hippocampus. Further, repeated treatment with lobeline or 3-(pyridine-3́-yl)-cytisine decreased immobility time in the FST and reduced withdrawal-induced increased BDNF and p-CREB expression in the hippocampus. CONCLUSIONS Taken together, our results indicate that lobeline attenuated nicotine withdrawal-induced depression-like behavior likely by targeting brain nAChRs, noradrenergic neurotransmission, and/or hippocampal BDNF. Thus, lobeline may have some potential to prevent smoking relapse by counteracting nicotine withdrawal-induced depression in humans.
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Affiliation(s)
- Monzurul Amin Roni
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Avera Health and Science Center, SAV 265, Brookings, SD, 57007, USA
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De Biasi M, McLaughlin I, Perez EE, Crooks PA, Dwoskin LP, Bardo MT, Pentel PR, Hatsukami D. Scientific overview: 2013 BBC plenary symposium on tobacco addiction. Drug Alcohol Depend 2014; 141:107-17. [PMID: 24934691 PMCID: PMC4227301 DOI: 10.1016/j.drugalcdep.2014.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/12/2014] [Accepted: 05/16/2014] [Indexed: 12/13/2022]
Abstract
Nicotine dependence plays a critical role in addiction to tobacco products, and thus contributes to a variety of devastating tobacco-related diseases (SGR 2014). Annual costs associated with smoking in the US are estimated to be between $289 and $333 billion. Effective interventions for nicotine dependence, especially in smokers, are a critical barrier to the eradication of tobacco-related diseases. This overview highlights research presented at the Plenary Symposium of Behavior, Biology and Chemistry: Translational Research in Addiction Conference (BBC), hosted by the UT Health Science Center San Antonio, on March 9-10, 2013. The Plenary Symposium focused on tobacco addiction, and covered topics ranging from basic science to national policy. As in previous years, the meeting brought together globally-renowned scientists, graduate student recruits, and young scientists from underrepresented populations in Texas and other states with the goal of fostering interest in drug addiction research in young generations.
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Affiliation(s)
- M De Biasi
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
| | - I McLaughlin
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - E E Perez
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - P A Crooks
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - L P Dwoskin
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - M T Bardo
- Department of Psychology, University of Kentucky, Lexington, KY, USA
| | - P R Pentel
- Department of Medicine, Hennepin County Medical Center, University of Minnesota, Minneapolis, MN, USA
| | - D Hatsukami
- Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA
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89
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Muldoon PP, Jackson KJ, Perez E, Harenza JL, Molas S, Rais B, Anwar H, Zaveri NT, Maldonado R, Maskos U, McIntosh JM, Dierssen M, Miles MF, Chen X, De Biasi M, Damaj MI. The α3β4* nicotinic ACh receptor subtype mediates physical dependence to morphine: mouse and human studies. Br J Pharmacol 2014; 171:3845-57. [PMID: 24750073 PMCID: PMC4128047 DOI: 10.1111/bph.12741] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 04/04/2014] [Accepted: 04/15/2014] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Recent data have indicated that α3β4* neuronal nicotinic (n) ACh receptors may play a role in morphine dependence. Here we investigated if nACh receptors modulate morphine physical withdrawal. EXPERIMENTAL APPROACHES To assess the role of α3β4* nACh receptors in morphine withdrawal, we used a genetic correlation approach using publically available datasets within the GeneNetwork web resource, genetic knockout and pharmacological tools. Male and female European-American (n = 2772) and African-American (n = 1309) subjects from the Study of Addiction: Genetics and Environment dataset were assessed for possible associations of polymorphisms in the 15q25 gene cluster and opioid dependence. KEY RESULTS BXD recombinant mouse lines demonstrated an increased expression of α3, β4 and α5 nACh receptor mRNA in the forebrain and midbrain, which significantly correlated with increased defecation in mice undergoing morphine withdrawal. Mice overexpressing the gene cluster CHRNA5/A3/B4 exhibited increased somatic signs of withdrawal. Furthermore, α5 and β4 nACh receptor knockout mice expressed decreased somatic withdrawal signs compared with their wild-type counterparts. Moreover, selective α3β4* nACh receptor antagonists, α-conotoxin AuIB and AT-1001, attenuated somatic signs of morphine withdrawal in a dose-related manner. In addition, two human datasets revealed a protective role for variants in the CHRNA3 gene, which codes for the α3 nACh receptor subunit, in opioid dependence and withdrawal. In contrast, we found that the α4β2* nACh receptor subtype is not involved in morphine somatic withdrawal signs. CONCLUSION AND IMPLICATIONS Overall, our findings suggest an important role for the α3β4* nACh receptor subtype in morphine physical dependence.
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Affiliation(s)
- P P Muldoon
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
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90
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Nicotine consumption is regulated by a human polymorphism in dopamine neurons. Mol Psychiatry 2014; 19:930-6. [PMID: 24296975 PMCID: PMC8596967 DOI: 10.1038/mp.2013.158] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 09/20/2013] [Accepted: 10/11/2013] [Indexed: 11/08/2022]
Abstract
Smoking is the most important preventable cause of morbidity and mortality worldwide. Recent genome-wide association studies highlighted a human haplotype on chromosome 15 underlying the risk for tobacco dependence and lung cancer. Several polymorphisms in the CHRNA3-CHRNA5-CHRNB4 cluster coding for the nicotinic acetylcholine receptor (nAChR) α3, α5 and β4 subunits were implicated. In mouse models, we define a key role in the control of sensitivity to nicotine for the α5 subunit in dopaminergic (DAergic) neurons of the ventral tegmental area (VTA). We first investigated the reinforcing effects of nicotine in drug-naive α5(-/-) mice using an acute intravenous nicotine self-administration task and ex vivo and in vivo electrophysiological recordings of nicotine-elicited DA cell activation. We designed lentiviral re-expression vectors to achieve targeted re-expression of wild-type or mutant α5 in the VTA, in general, or in DA neurons exclusively. Our results establish a crucial role for α5*-nAChRs in DAergic neurons. These receptors are key regulators that determine the minimum nicotine dose necessary for DA cell activation and thus nicotine reinforcement. Finally, we demonstrate that a single-nucleotide polymorphism, the non-synonymous α5 variant rs16969968, frequent in many human populations, exhibits a partial loss of function of the protein in vivo. This leads to increased nicotine consumption in the self-administration paradigm. We thus define a critical link between a human predisposition marker, its expression in DA neurons and nicotine intake.
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91
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Vandenbergh DJ, Schlomer GL. Finding genomic function for genetic associations in nicotine addiction research: the ENCODE project's role in future pharmacogenomic analysis. Pharmacol Biochem Behav 2014; 123:34-44. [PMID: 24486638 PMCID: PMC4117825 DOI: 10.1016/j.pbb.2014.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 01/17/2014] [Accepted: 01/22/2014] [Indexed: 11/16/2022]
Abstract
Tobacco-related behaviors and the underlying addiction to nicotine are complex tangles of genetic and environmental factors. Efforts to understand the genetic component of these traits have identified sites in the genome (single nucleotide polymorphisms, or SNPs) that might account for some part of the role of genetics in nicotine addiction. Encouragingly, some of these candidate SNPs remain significant in meta-analyses. However, genetic associations cannot be fully assessed, regardless of statistical significance, without an understanding of the functional consequences of the alleles present at these SNPs. The proper experimental test for allelic function can be very difficult to define, representing a roadblock in translating genetic results into treatment to prevent smoking and other nicotine-related behaviors. This roadblock can be navigated in part with a new web-based tool, the Encyclopedia of DNA Elements (ENCODE). ENCODE is a compilation of searchable data on several types of biochemical functions or "marks" across the genome. These data can be queried for the co-localization of a candidate SNP and a biochemical mark. The presence of a SNP within a marked region of DNA enables the generation of better-informed hypotheses to test possible functional roles of alleles at a candidate SNP. Two examples of such co-localizations are presented. One example reveals ENCODE's ability to relate a candidate SNP's function with a gene very far from the physical location of the SNP. The second example reveals a new potential function of the SNP, rs4105144, that has been genetically associated with the number of cigarettes smoked per day. Details for accessing the ENCODE data for this SNP are provided to serve as a tutorial. By serving as a bridge between genetic associations and biochemical function, ENCODE has the power to propel progress in untangling the genetic aspects of nicotine addiction - a major public health concern.
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Affiliation(s)
- David J Vandenbergh
- Department of Biobehavioral Health, The Pennsylvania State University, 219 Biobehavioral Health Building, University Park, PA 16802, USA; Penn State Institute of the Neurosciences, 101 Life Sciences Building, University Park, PA 16802, USA.
| | - Gabriel L Schlomer
- Department of Human Development and Family Studies, The Pennsylvania State University, 315 Health and Human Development, East, University Park, PA 16802, USA.
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92
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Renda A, Nashmi R. Chronic nicotine pretreatment is sufficient to upregulate α4* nicotinic receptors and increase oral nicotine self-administration in mice. BMC Neurosci 2014; 15:89. [PMID: 25038610 PMCID: PMC4133059 DOI: 10.1186/1471-2202-15-89] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 07/15/2014] [Indexed: 01/18/2023] Open
Abstract
Background Understanding the underlying causes of nicotine addiction will require a multidisciplinary approach examining the key molecular, cellular and neuronal circuit functional changes that drive escalating levels of nicotine self-administration. In this study, we examined whether mice pretreated with chronic nicotine, at a dosing regimen that results in maximal nicotinic acetylcholine receptor (nAChR) upregulation, would display evidence of nicotine-dependent behaviour during nicotine self-administration. Results We investigated oral self-administration of nicotine using a two-bottle choice paradigm in which one bottle contained the vehicle (saccharine-sweetened water), while the other contained nicotine (200 μg/ml) in vehicle. Knock-in mice with YFP-tagged α4 nAChR subunits (α4YFP) were implanted with osmotic pumps delivering either nicotine (2 mg/kg/hr) or saline for 10 days. After 10 days of pretreatment, mice were exposed to the nicotine self-administration paradigm, consisting of four days of choice followed by three days of nicotine abstinence repeated for five weeks. Mice pre-exposed to nicotine had upregulated α4YFP nAChR subunits in the hippocampal medial perforant path and on ventral tegmental area GABAergic neurons as compared to chronic saline mice. Compared to control saline-pretreated mice, in a two bottle-choice experiment, nicotine-primed mice ingested a significantly larger daily dose of nicotine and also exhibited post-abstinence binge drinking of nicotine. Conclusions Chronic forced pre-exposure of nicotine is sufficient to induce elevated oral nicotine intake and supports the postulate that nAChR upregulation may be a key factor influencing nicotine self-administration.
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Affiliation(s)
| | - Raad Nashmi
- Department of Biology, University of Victoria, PO Box 3020, Station CSC, Victoria, BC V8W 3 N5, Canada.
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93
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Simmons SJ, Gould TJ. Involvement of neuronal β2 subunit-containing nicotinic acetylcholine receptors in nicotine reward and withdrawal: implications for pharmacotherapies. J Clin Pharm Ther 2014; 39:457-67. [PMID: 24828779 DOI: 10.1111/jcpt.12171] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 04/14/2014] [Indexed: 11/28/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Tobacco smoking remains a major health problem. Nicotine binds to nicotinic acetylcholine receptors (nAChRs), which can cause addiction and withdrawal symptoms upon cessation of nicotine administration. Pharmacotherapies for nicotine addiction target brain alterations that underlie withdrawal symptoms. This review will delineate the involvement of the β2 subunit of neuronal nAChRs in nicotine reward and in generating withdrawal symptoms to better understand the efficacy of smoking cessation pharmacotherapies. COMMENT Chronic nicotine desensitizes and upregulates β2 subunit-containing nAChRs, and the prolonged upregulation of receptors may underlie symptoms of withdrawal. Experimental research has demonstrated that the β2 subunit of neuronal nAChRs is necessary for generating nicotine reward and withdrawal symptoms. WHAT IS NEW AND CONCLUSION Smoking cessation pharmacotherapies act on β2 subunit-containing nAChRs to reduce nicotine reward and withdrawal symptom severity.
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Affiliation(s)
- Steven J Simmons
- Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA, 19122, USA
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94
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Nicotine enhances excitability of medial habenular neurons via facilitation of neurokinin signaling. J Neurosci 2014; 34:4273-84. [PMID: 24647947 DOI: 10.1523/jneurosci.2736-13.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The medial habenula (MHb) densely expresses nicotinic acetylcholine receptors (nAChRs) and participates in nicotine-related behaviors such as nicotine withdrawal and regulating nicotine intake. Although specific nAChR subunits are identified as being involved in withdrawal behavior, the cellular mechanisms through which nicotine acts to cause this aversive experience is unclear. Here, we demonstrate an interaction between the nicotinic and neurokinin signaling systems that may form the basis for some symptoms experienced during nicotine withdrawal. Using patch-clamp electrophysiology in mouse brain slices, we show that nicotine (1 μm) increases intrinsic excitability in MHb neurons. This nicotine-induced phenomenon requires α5-containing nAChRs and depends on intact neurokinin signaling. The effect is blocked by preincubation with neurokinin 1 (NK1; L-732138, 10 μm) and NK3 (SB222200, 2 μm) antagonists and mimicked by NK1 (substance P, 100 nm) and NK3 (neurokinin B [NKB], 100 nm) agonists. Microinjections (1 μl) of L-732138 (50 nm) and SB222200 (100 nm) into the MHb induces withdrawal behavior in chronic nicotine-treated (8.4 mg/kg/d, 2 weeks) mice. Conversely, withdrawal behavior is absent with analogous microinjections into the lateral habenula of nicotine-treated mice or in mice chronically treated with a vehicle solution. Further, chronic nicotine reduces nicotine's acute modulation of intrinsic excitability while sparing modulation by NKB. Our work elucidates the interplay between two neuromodulatory signaling systems in the brain through which nicotine acts to influence intrinsic excitability. More importantly, we document a neuroadaptation of this mechanism to chronic nicotine exposure and implicate these mechanisms collectively in the emergence of nicotine withdrawal behavior.
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95
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Brunzell DH, McIntosh JM, Papke RL. Diverse strategies targeting α7 homomeric and α6β2* heteromeric nicotinic acetylcholine receptors for smoking cessation. Ann N Y Acad Sci 2014; 1327:27-45. [PMID: 24730978 DOI: 10.1111/nyas.12421] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Preclinical studies suggest that a diversity of nicotinic acetylcholine receptors (nAChRs) with different sensitivities to nicotine may contribute to tobacco addiction. Using rodent intravenous nicotine self-administration as a preclinical model with good predictive validity for therapeutic efficacy for tobacco cessation, investigators have identified heteromeric α6β2* and homomeric α7 nAChRs as promising novel therapeutic targets to promote smoking abstinence (*denotes possible assembly with other subunits). The data suggest that diverse strategies that target these subclasses of nAChRs, namely inhibition of α6β2* nAChRs and stimulation of α7 nAChRs, will support tobacco cessation. α6β2* nAChRs, members of the high-affinity family of β2* nAChRs, function similarly to α4β2* nAChRs, the primary target of the FDA-approved drug varenicline, but have a much more selective neuroanatomical pattern of expression in catecholaminergic nuclei. Although activation of β2* nAChRs facilitates nicotine self-administration, stimulation of α7 nAChRs appears to negatively modulate both nicotine reinforcement and β2* nAChR function in the mesolimbic dopamine system. Although challenges and caveats must be considered in the development of therapeutics that target these nAChR subpopulations, an accumulation of data suggests that α7 nAChR agonists, partial agonists, or positive allosteric modulators and α6β2* nAChR antagonists, partial agonists, or negative allosteric modulators may prove to be effective therapeutics for tobacco cessation.
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Affiliation(s)
- Darlene H Brunzell
- Department of Pharmacology and Toxicology, Interdisciplinary Neuroscience Program and Institute for Drug and Alcohol Studies, Virginia Commonwealth University School of Medicine, Richmond, Virginia
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96
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Velasquez KM, Molfese DL, Salas R. The role of the habenula in drug addiction. Front Hum Neurosci 2014; 8:174. [PMID: 24734015 PMCID: PMC3975120 DOI: 10.3389/fnhum.2014.00174] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 03/09/2014] [Indexed: 01/06/2023] Open
Abstract
Interest in the habenula has greatly increased in recent years. The habenula is a small brain structure located posterior to the thalamus and adjacent to the third ventricle. Despite its small size, the habenula can be divided into medial habenula (MHb) and lateral habenula (LHb) nuclei that are anatomically and transcriptionally distinct. The habenula receives inputs from the limbic system and basal ganglia primarily via the stria medullaris. The fasciculus retroflexus is the primary habenular output from the habenula to the midbrain and governs release of glutamate onto gabaergic cells in the rostromedial tegmental nucleus (RMTg) and onto the interpeduncular nucleus. The resulting GABA released from RMTg neurons inactivates dopaminergic cells in the ventral tegmental area/substantia nigra compacta. Through this process, the habenula controls dopamine levels in the striatum. Thus, the habenula plays a critical role in reward and reward-associated learning. The LHb also modulates serotonin levels and norepinephrine release, while the MHb modulates acetylcholine. The habenula is a critical crossroad that influences the brain’s response to pain, stress, anxiety, sleep, and reward. Dysfunction of the habenula has been linked to depression, schizophrenia, and the effects of drugs of abuse. This review focuses on the possible relationships between the habenula and drug abuse.
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Affiliation(s)
- Kenia M Velasquez
- Department of Psychiatry, Baylor College of Medicine Houston, TX, USA
| | - David L Molfese
- Department of Psychiatry, Baylor College of Medicine Houston, TX, USA
| | - Ramiro Salas
- Department of Psychiatry, Baylor College of Medicine Houston, TX, USA
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97
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Viswanath H, Carter AQ, Baldwin PR, Molfese DL, Salas R. The medial habenula: still neglected. Front Hum Neurosci 2014; 7:931. [PMID: 24478666 PMCID: PMC3894476 DOI: 10.3389/fnhum.2013.00931] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 12/22/2013] [Indexed: 01/23/2023] Open
Abstract
The habenula is a small, bilateral brain structure located at the dorsal end of the diencephalon. This structure sends projections to the dopaminergic striatum and receives inputs from the limbic forebrain, making the habenula a unique modulator of cross-talk between these brain regions. Despite strong interest in the habenula during the seventies and eighties (Herkenham and Nauta, 1977; Beckstead, 1979; Beckstead et al., 1979; Herkenham and Nauta, 1979; Caldecott-Hazard et al., 1988), interest waned due to lack of a clearly identifiable functional role. Following Matsumoto and Hikosaka's seminal work on the lateral habenula as a predictor of negative reward in monkeys, the habenula has undergone a resurgence of scientific interest. Matsumoto and Hikosaka demonstrated an increase in habenular neuron firing when monkeys did not receive an expected juice reward (Matsumoto and Hikosaka, 2007). Studies have shown that increased habenular activity inactivates dopaminergic cells in the Rostromedial Tegmental Nucleus (RMTg) through GABAergic mechanisms (Jhou et al., 2009a,b). Additional studies link habenular activity to the regulation of serotonin and norepinephrine, suggesting the habenula modulates multiple brain systems (Strecker and Rosengren, 1989; Amat et al., 2001). These discoveries ushered in a series of new studies that have refocused attention on the lateral habenula and the importance of this small brain structure (Bianco and Wilson, 2009; Jhou et al., 2009a; Matsumoto and Hikosaka, 2009; Sartorius et al., 2010; Savitz et al., 2011). Recently, Geisler and Trimble reviewed this renewed interest in: The Lateral Habenula: No Longer Neglected (Geisler and Trimble, 2008). While the lateral habenula (LHb) has been extensively studied, the anatomically and histochemically distinct medial habenula (MHb) remains largely understudied. This short review argues that the MHb is functionally important and should be studied more aggressively.
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Affiliation(s)
| | | | | | | | - Ramiro Salas
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of MedicineHouston, TX, USA
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98
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Cholinergic left-right asymmetry in the habenulo-interpeduncular pathway. Proc Natl Acad Sci U S A 2013; 110:21171-6. [PMID: 24327734 DOI: 10.1073/pnas.1319566110] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The habenulo-interpeduncular pathway, a highly conserved cholinergic system, has emerged as a valuable model to study left-right asymmetry in the brain. In larval zebrafish, the bilaterally paired dorsal habenular nuclei (dHb) exhibit prominent left-right differences in their organization, gene expression, and connectivity, but their cholinergic nature was unclear. Through the discovery of a duplicated cholinergic gene locus, we now show that choline acetyltransferase and vesicular acetylcholine transporter homologs are preferentially expressed in the right dHb of larval zebrafish. Genes encoding the nicotinic acetylcholine receptor subunits α2 and β4 are transcribed in the target interpeduncular nucleus (IPN), suggesting that the asymmetrical cholinergic pathway is functional. To confirm this, we activated channelrhodopsin-2 specifically in the larval dHb and performed whole-cell patch-clamp recording of IPN neurons. The response to optogenetic or electrical stimulation of the right dHb consisted of an initial fast glutamatergic excitatory postsynaptic current followed by a slow-rising cholinergic current. In adult zebrafish, the dHb are divided into discrete cholinergic and peptidergic subnuclei that differ in size between the left and right sides of the brain. After exposing adults to nicotine, fos expression was activated in subregions of the IPN enriched for specific nicotinic acetylcholine receptor subunits. Our studies of the newly identified cholinergic gene locus resolve the neurotransmitter identity of the zebrafish habenular nuclei and reveal functional asymmetry in a major cholinergic neuromodulatory pathway of the vertebrate brain.
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99
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Zhao-Shea R, Liu L, Pang X, Gardner PD, Tapper AR. Activation of GABAergic neurons in the interpeduncular nucleus triggers physical nicotine withdrawal symptoms. Curr Biol 2013; 23:2327-35. [PMID: 24239118 DOI: 10.1016/j.cub.2013.09.041] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 09/06/2013] [Accepted: 09/19/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronic exposure to nicotine elicits physical dependence in smokers, yet the mechanism and neuroanatomical bases for withdrawal symptoms are unclear. As in humans, rodents undergo physical withdrawal symptoms after cessation from chronic nicotine characterized by increased scratching, head nods, and body shakes. RESULTS Here we show that induction of physical nicotine withdrawal symptoms activates GABAergic neurons within the interpeduncular nucleus (IPN). Optical activation of IPN GABAergic neurons via light stimulation of channelrhodopsin elicited physical withdrawal symptoms in both nicotine-naive and chronic-nicotine-exposed mice. Dampening excitability of GABAergic neurons during nicotine withdrawal through IPN-selective infusion of an NMDA receptor antagonist or through blockade of IPN neurotransmission from the medial habenula reduced IPN neuronal activation and alleviated withdrawal symptoms. During chronic nicotine exposure, nicotinic acetylcholine receptors containing the β4 subunit were upregulated in somatostatin interneurons clustered in the dorsal region of the IPN. Blockade of these receptors induced withdrawal signs more dramatically in nicotine-dependent compared to nicotine-naive mice and activated nonsomatostatin neurons in the IPN. CONCLUSIONS Together, our data indicate that therapeutic strategies to reduce IPN GABAergic neuron excitability during nicotine withdrawal, for example, by activating nicotinic receptors on somatostatin interneurons, may be beneficial for alleviating withdrawal symptoms and facilitating smoking cessation.
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Affiliation(s)
- Rubing Zhao-Shea
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
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100
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Role of CB2 cannabinoid receptors in the rewarding, reinforcing, and physical effects of nicotine. Neuropsychopharmacology 2013; 38:2515-24. [PMID: 23817165 PMCID: PMC3799072 DOI: 10.1038/npp.2013.157] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 06/18/2013] [Accepted: 06/20/2013] [Indexed: 01/21/2023]
Abstract
This study was aimed to evaluate the involvement of CB2 cannabinoid receptors (CB2r) in the rewarding, reinforcing and motivational effects of nicotine. Conditioned place preference (CPP) and intravenous self-administration experiments were carried out in knockout mice lacking CB2r (CB2KO) and wild-type (WT) littermates treated with the CB2r antagonist AM630 (1 and 3 mg/kg). Gene expression analyses of tyrosine hydroxylase (TH) and α3- and α4-nicotinic acetylcholine receptor subunits (nAChRs) in the ventral tegmental area (VTA) and immunohistochemical studies to elucidate whether CB2r colocalized with α3- and α4-nAChRs in the nucleus accumbens and VTA were performed. Mecamylamine-precipitated withdrawal syndrome after chronic nicotine exposure was evaluated in CB2KO mice and WT mice treated with AM630 (1 and 3 mg/kg). CB2KO mice did not show nicotine-induced place conditioning and self-administered significantly less nicotine. In addition, AM630 was able to block (3 mg/kg) nicotine-induced CPP and reduce (1 and 3 mg/kg) nicotine self-administration. Under baseline conditions, TH, α3-nAChR, and α4-nAChR mRNA levels in the VTA of CB2KO mice were significantly lower compared with WT mice. Confocal microscopy images revealed that CB2r colocalized with α3- and α4-nAChRs. Somatic signs of nicotine withdrawal (rearings, groomings, scratches, teeth chattering, and body tremors) increased significantly in WT but were absent in CB2KO mice. Interestingly, the administration of AM630 blocked the nicotine withdrawal syndrome and failed to alter basal behavior in saline-treated WT mice. These results suggest that CB2r play a relevant role in the rewarding, reinforcing, and motivational effects of nicotine. Pharmacological manipulation of this receptor deserves further consideration as a potential new valuable target for the treatment of nicotine dependence.
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