1
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Papke RL. Functions and pharmacology of α2β2 nicotinic acetylcholine receptors; in and out of the shadow of α4β2 nicotinic acetylcholine receptors. Biochem Pharmacol 2024; 225:116263. [PMID: 38735444 DOI: 10.1016/j.bcp.2024.116263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/14/2024]
Abstract
Although α2 was the first neuronal nicotinic acetylcholine receptor (nAChR) receptor subunit to be cloned, due to its low level of expression in rodent brain, its study has largely been neglected. This study provides a comparison of the α2 and α4 structures and their functional similarities, especially in regard to the existence of low and high sensitivity forms based on subunit stoichiometry. We show that the pharmacological profiles of the low and high sensitivity forms of α2β2 and α4β2 receptors are very similar in their responses to nicotine, with high sensitivity receptors showing protracted responses. Sazetidine A, an agonist that is selective for the high sensitivity α4 receptors also selectively activates high sensitivity α2 receptors. Likewise, α2 receptors have similar responses as α4 receptors to the positive allosteric modulators (PAMs) desformylflustrabromine (dFBr) and NS9283. We show that the partial agonists for α4β2 receptors, cytisine and varenicline are also partial agonists for α2β2 receptors. Studies have shown that levels of α2 expression may be much higher in the brains of primates than those of rodents, suggesting a potential importance for human therapeutics. High-affinity nAChR have been studied in humans with PET ligands such as flubatine. We show that flubatine has similar activity with α2β2 and α4β2 receptors so that α2 receptors will also be detected in PET studies that have previously presumed to selectively detect α4β2 receptors. Therefore, α2 receptors need more consideration in the development of therapeutics to manage nicotine addiction and declining cholinergic function in age and disease.
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Affiliation(s)
- Roger L Papke
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610 USA.
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2
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Kumar M, Keady J, Aryal SP, Hessing M, Richards CI, Turner JR. The Role of Microglia in Sex- and Region-Specific Blood-Brain Barrier Integrity During Nicotine Withdrawal. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:182-193. [PMID: 38298802 PMCID: PMC10829673 DOI: 10.1016/j.bpsgos.2023.08.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 08/18/2023] [Accepted: 08/19/2023] [Indexed: 02/02/2024] Open
Abstract
Background Smoking is the largest preventable cause of death and disease in the United States, with <5% of quit attempts being successful. Microglia activation and proinflammatory neuroimmune signaling in reward neurocircuitry are implicated in nicotine withdrawal symptomology. Microglia are integral regulators of blood-brain barrier (BBB) functionality as well; however, whether the effects of nicotine withdrawal on microglia function impact BBB integrity is unknown. Methods Mice were treated with chronic nicotine (12 mg/kg/day) and subjected to 48 hours nicotine withdrawal. Regional BBB permeability, together with messenger RNA and protein expression of tight junction proteins, were assessed. PLX5622 chow was used to deplete microglia to evaluate the role of microglia in regulating BBB integrity and nicotine withdrawal symptomology. Results Female mice had higher baseline BBB permeability in the prefrontal cortex and hippocampus than males. Nicotine withdrawal further exacerbated the BBB permeability selectively in the prefrontal cortex of females. These effects were concurrent with prefrontal cortex alterations in a subset of tight junction proteins with increased proinflammatory responses following nicotine withdrawal in females. Depletion of microglia via PLX5622 treatment prevented all these molecular effects and attenuated withdrawal-induced anxiety-like behavior in female mice. Conclusions These results are the first to show sex differences in regional BBB permeability during nicotine withdrawal. This represents a possible link to both the reduced smoking cessation success seen in women and women's increased risk for smoking-related neurovascular disorders. Furthermore, these findings open an avenue for sex-specific therapeutics that target microglia and BBB dysfunction during nicotine withdrawal in women.
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Affiliation(s)
- Mohit Kumar
- University of Kentucky, College of Pharmacy, Lexington, Kentucky
- Food & Nutrition Biotechnology Division, Centre for Excellence in Functional Foods, National Agri-Food Biotechnology Institute, Sahibzada Ajit Singh Nagar, Punjab, India
| | - Jack Keady
- University of Kentucky, College of Pharmacy, Lexington, Kentucky
| | - Surya P. Aryal
- Department of Chemistry, University of Kentucky, Lexington, Kentucky
| | - Marissa Hessing
- University of Kentucky, College of Pharmacy, Lexington, Kentucky
| | | | - Jill R. Turner
- University of Kentucky, College of Pharmacy, Lexington, Kentucky
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3
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Ghimire M, Cai R, Ling L, Brownell KA, Wisner KW, Cox BC, Hackett TA, Brozoski TJ, Caspary DM. Desensitizing nicotinic agents normalize tinnitus-related inhibitory dysfunction in the auditory cortex and ameliorate behavioral evidence of tinnitus. Front Neurosci 2023; 17:1197909. [PMID: 37304018 PMCID: PMC10248052 DOI: 10.3389/fnins.2023.1197909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 04/25/2023] [Indexed: 06/13/2023] Open
Abstract
Tinnitus impacts between 10-20% of the population. Individuals most troubled by their tinnitus have their attention bound to and are distracted by, their tinnitus percept. While numerous treatments to ameliorate tinnitus have been tried, no therapeutic approach has been clinically accepted. The present study used an established condition-suppression noise-exposure rat model of tinnitus to: (1) examine tinnitus-related changes in nAChR function of layer 5 pyramidal (PNs) and of vasoactive intestinal peptide (VIP) neurons in primary auditory cortex (A1) and (2) examine how the partial desensitizing nAChR agonists, sazetidine-A and varenicline, can act as potential therapeutic agents in the treatment of tinnitus. We posited that tinnitus-related changes in layer 5 nAChR responses may underpin the decline in attentional resources previously observed in this animal model (Brozoski et al., 2019). In vitro whole-cell patch-clamp studies previously revealed a significant tinnitus-related loss in nAChR-evoked excitatory postsynaptic currents from A1 layer 5 PNs. In contrast, VIP neurons from animals with behavioral evidence of tinnitus showed significantly increased nAChR-evoked excitability. Here we hypothesize that sazetidine-A and varenicline have therapeutic benefits for subjects who cannot divert their attention away from the phantom sound in their heads. We found that sazetidine-A or varenicline normalized tinnitus-related reductions in GABAergic input currents onto A1 layer 5 PNs. We then tested sazetidine-A and varenicline for the management of tinnitus using our tinnitus animal model. Subcutaneous injection of sazetidine-A or varenicline, 1 h prior to tinnitus testing, significantly decreased the rat's behavioral evidence of tinnitus in a dose-dependent manner. Collectively, these results support the need for additional clinical investigations of partial desensitizing nAChR agonists sazetidine-A and varenicline for the treatment of tinnitus.
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Affiliation(s)
- Madan Ghimire
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Rui Cai
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Lynne Ling
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Kevin A. Brownell
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Kurt W. Wisner
- Department of Otolaryngology, Head and Neck Surgery, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Brandon C. Cox
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Otolaryngology, Head and Neck Surgery, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Troy A. Hackett
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Thomas J. Brozoski
- Department of Otolaryngology, Head and Neck Surgery, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Donald M. Caspary
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Otolaryngology, Head and Neck Surgery, Southern Illinois University School of Medicine, Springfield, IL, United States
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4
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Terry AV, Jones K, Bertrand D. Nicotinic acetylcholine receptors in neurological and psychiatric diseases. Pharmacol Res 2023; 191:106764. [PMID: 37044234 DOI: 10.1016/j.phrs.2023.106764] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/30/2023] [Accepted: 04/07/2023] [Indexed: 04/14/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that are widely distributed both pre- and post-synaptically in the mammalian brain. By modulating cation flux across cell membranes, neuronal nAChRs regulate neuronal excitability and the release of a variety of neurotransmitters to influence multiple physiologic and behavioral processes including synaptic plasticity, motor function, attention, learning and memory. Abnormalities of neuronal nAChRs have been implicated in the pathophysiology of neurologic disorders including Alzheimer's disease, Parkinson's disease, epilepsy, and Tourette´s syndrome, as well as psychiatric disorders including schizophrenia, depression, and anxiety. The potential role of nAChRs in a particular illness may be indicated by alterations in the expression of nAChRs in relevant brain regions, genetic variability in the genes encoding for nAChR subunit proteins, and/or clinical or preclinical observations where specific ligands showed a therapeutic effect. Over the past 25 years, extensive preclinical and some early clinical evidence suggested that ligands at nAChRs might have therapeutic potential for neurologic and psychiatric disorders. However, to date the only approved indications for nAChR ligands are smoking cessation and the treatment of dry eye disease. It has been argued that progress in nAChR drug discovery has been limited by translational gaps between the preclinical models and the human disease as well as unresolved questions regarding the pharmacological goal (i.e., agonism, antagonism or receptor desensitization) depending on the disease.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912.
| | - Keri Jones
- Educational Innovation Institute, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912
| | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222 Vésenaz, Geneva, Switzerland
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5
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Kamens HM, Flarend G, Horton WJ. The role of nicotinic receptors in alcohol consumption. Pharmacol Res 2023; 190:106705. [PMID: 36813094 PMCID: PMC10083870 DOI: 10.1016/j.phrs.2023.106705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/14/2023] [Accepted: 02/19/2023] [Indexed: 02/22/2023]
Abstract
The use of alcohol causes significant morbidity and mortality across the globe. Alcohol use disorder (AUD) is defined by the excessive use of this drug despite a negative impact on the individual's life. While there are currently medications available to treat AUD, they have limited efficacy and several side effects. As such, it is essential to continue to look for novel therapeutics. One target for novel therapeutics is nicotinic acetylcholine receptors (nAChRs). Here we systematically review the literature on the involvement of nAChRs in alcohol consumption. Data from both genetic and pharmacology studies provide evidence that nAChRs modulate alcohol intake. Interestingly, pharmacological modulation of all nAChR subtypes examined can decrease alcohol consumption. The reviewed literature demonstrates that nAChRs should continue to be investigated as novel therapeutics for AUD.
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Affiliation(s)
- Helen M Kamens
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA 16802, United States.
| | - Geneva Flarend
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA 16802, United States
| | - William J Horton
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA 16802, United States
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Papke RL, Stokes C. Insights Into the Differential Desensitization of α4 β2 Nicotinic Acetylcholine Receptor Isoforms Obtained With Positive Allosteric Modulation of Mutant Receptors. Mol Pharmacol 2023; 103:63-76. [PMID: 36414373 PMCID: PMC9881010 DOI: 10.1124/molpharm.122.000591] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/25/2022] [Accepted: 11/03/2022] [Indexed: 11/23/2022] Open
Abstract
The development of highly efficacious positive allosteric modulators (PAMs) of α7 nicotinic acetylcholine receptors (nAChR) has proven useful in defining the ligand dependence of the conformational dynamics of α7 receptors. No such effective modulators are known to exist for the α4β2 nAChR of the brain, limiting our ability to understand the importance of desensitization for the activity profile of specific ligands. In this study, we used mutant β2 subunits that allowed the use of the α7 PAM 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide (TQS) to probe the desensitizing effects of nicotinic ligands on the two forms of α4β2 receptors; high sensitivity (HS) (two α4 and three β2 subunits) and low sensitivity (LS) (three α4 and two β2 subunits). A total of 28 different ligands of 8 different categories, based on activity and selectivity, were tested for their ability to induce TQS-sensitive desensitization of HS and LS α4β2 receptors. Results confirm that HS α4β2 receptor responses are strongly limited by desensitization, by at least an order of magnitude more so than the responses of LS receptors. The activation of α4β2 receptors by the smoking-cessation drugs cytisine and varenicline is strongly limited by desensitization, as is the activation of LS receptors by the HS-selective agonists 6-[5-[(2S)-2-Azetidinylmethoxy]-3-pyridinyl]-5-hexyn-1-ol dihydrochloride and 4-(5-ethoxy-3-pyridinyl)-N-methyl-(3E)-3-buten-1-amine difumarate. The evaluation of drugs previously identified as α7-selective agonists revealed varying patterns of α4β2 cross-desensitization that were predictive of the effects of these drugs on the activation of wild-type α4β2 receptors by acetylcholine, supporting the utility of TQS-sensitive receptors for the development of focused therapeutics. SIGNIFICANCE STATEMENT: To varying degrees, ligands regulate the balance of active and desensitized states of the two forms of the primary nAChR subtypes in brain. Using mutant beta subunits, an allosteric modulator can reverse ligand-induced desensitization, revealing the differential desensitization of the receptors by specific ligands. This study shows that drugs believed to be selective for therapeutic targets may cross-desensitize other targets and that, within a class of drugs, improved specificity can be achieved by using agents that reduce such cross-desensitization.
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Affiliation(s)
- Roger L Papke
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida
| | - Clare Stokes
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida
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7
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Slobodyanyuk M, Banda-Vázquez JA, Thompson MJ, Dean RA, Baenziger JE, Chica RA, daCosta CJB. Origin of acetylcholine antagonism in ELIC, a bacterial pentameric ligand-gated ion channel. Commun Biol 2022; 5:1264. [PMID: 36400839 PMCID: PMC9674596 DOI: 10.1038/s42003-022-04227-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 11/04/2022] [Indexed: 11/20/2022] Open
Abstract
ELIC is a prokaryotic homopentameric ligand-gated ion channel that is homologous to vertebrate nicotinic acetylcholine receptors. Acetylcholine binds to ELIC but fails to activate it, despite bringing about conformational changes indicative of activation. Instead, acetylcholine competitively inhibits agonist-activated ELIC currents. What makes acetylcholine an agonist in an acetylcholine receptor context, and an antagonist in an ELIC context, is not known. Here we use available structures and statistical coupling analysis to identify residues in the ELIC agonist-binding site that contribute to agonism. Substitution of these ELIC residues for their acetylcholine receptor counterparts does not convert acetylcholine into an ELIC agonist, but in some cases reduces the sensitivity of ELIC to acetylcholine antagonism. Acetylcholine antagonism can be abolished by combining two substitutions that together appear to knock out acetylcholine binding. Thus, making the ELIC agonist-binding site more acetylcholine receptor-like, paradoxically reduces the apparent affinity for acetylcholine, demonstrating that residues important for agonist binding in one context can be deleterious in another. These findings reinforce the notion that although agonism originates from local interactions within the agonist-binding site, it is a global property with cryptic contributions from distant residues. Finally, our results highlight an underappreciated mechanism of antagonism, where agonists with appreciable affinity, but negligible efficacy, present as competitive antagonists. A structural and functional study of the prokaryotic ligand-gated ion channel, ELIC, provides insight into the origin of agonism and antagonism at nicotinic acetylcholine receptors.
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8
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Decker S, Davis G, Vahora I, Vukovic A, Patel P, Suryanarayanan A. Desformylflustrabromine (dFBr), a positive allosteric modulator of α4β2 nicotinic acetylcholine receptors decreases voluntary ethanol consumption and preference in male and female Sprague-Dawley rats. PLoS One 2022; 17:e0273715. [PMID: 36084045 PMCID: PMC9462806 DOI: 10.1371/journal.pone.0273715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 08/11/2022] [Indexed: 11/19/2022] Open
Abstract
Alcohol use disorder is a medical condition that impacts millions of individuals worldwide. Although there are a few pharmacotherapeutic options for alcohol-dependent individuals; there is a need for the development of novel and more effective therapeutic approaches. Alcohol and nicotine are commonly co-abused, and there is evidence that neuronal nicotinic acetylcholine receptors (nAChRs) play a role in both alcohol and nicotine dependence. Desformylflustrabromine (dFBr), a positive allosteric modulator of the α4β2 nAChRs has been shown to reduce nicotine intake, compulsive-like behavior and neuropathic pain in animal models. dFBr has also been previously shown to cross the blood-brain-barrier. We have recently shown that dFBr can attenuate the response to an acute, hypnotic dose of ethanol, via β2 nAchR. Here, we have investigated the effect of dFBr in modulating ethanol consumption using the intermittent access two-bottle choice (IA2BC) model of voluntary ethanol consumption in male and female Sprague Dawley rats. We show that dFBr selectively reduced ethanol but not sucrose consumption in the IA2BC model. Furthermore, dFBr decreased preference for ethanol in both male and female rats. No rebound increase in ethanol intake was observed after the washout period after dFBr treatment. The ability of dFBr to decrease ethanol consumption, along with its previously demonstrated ability to decrease nicotine self-administration in rodents, suggest that dFBr is an attractive therapeutic candidate to target both nicotine and alcohol abuse.
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Affiliation(s)
- Steven Decker
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, United States of America
| | - Gregory Davis
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, United States of America
| | - Imran Vahora
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, United States of America
| | - Alen Vukovic
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, United States of America
| | - Parth Patel
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, United States of America
| | - Asha Suryanarayanan
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, United States of America
- * E-mail:
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9
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Understanding the stimulus effects of nicotine and bupropion in a drug-drug discriminated goal-tracking task. Psychopharmacology (Berl) 2022; 239:819-830. [PMID: 35137248 DOI: 10.1007/s00213-022-06072-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 01/23/2022] [Indexed: 10/19/2022]
Abstract
RATIONALE Bupropion is a non-nicotine medication for smoking cessation that has overlapping stimulus effects with nicotine as demonstrated in drug discrimination studies. Whether these shared stimulus effects will alter acquisition or maintenance of a discrimination between nicotine and bupropion is unknown. OBJECTIVE We sought to test this possibility using the drug discriminated goal-tracking (DGT) task and whether discrimination training history affected generalization and substitution tests. METHODS Sixty adult Sprague-Dawley rats (30M/30F) were equally split into three discrimination training groups: SAL-0.4NIC, 10BUP-0.4NIC, and 20BUP-0.4NIC. On nicotine days, all rats were administered subcutaneously 0.4 mg/kg nicotine and had intermittent access to liquid sucrose. On intermixed non-reinforced days, rats were administered intraperitoneally saline, 10 or 20 mg/kg bupropion. Upon completion, a range of nicotine and bupropion doses were assessed before substitution tests with varenicline and sazetidine-A were conducted. RESULTS The SAL-0.4NIC and 10BUP-0.4NIC groups readily discriminated by session 8, as evidenced by increased dipper entries (goal-tracking) on nicotine days. The 20BUP-0.4NIC group was slower to acquire the discrimination. Female rats, regardless of group, had higher conditioned responding evoked by the lowest dose of nicotine (0.025 mg/kg) in the dose-effect curve. The discrimination required rats to learn to withhold responding to the training dose of bupropion. This withholding of excitatory dipper entries generalized to other doses. Varenicline and sazetidine-A partially substituted for the nicotine stimulus, and this pattern did not differ with training history. CONCLUSIONS We are the first to study a drug-drug discrimination using the DGT task. Females appeared to have a lower discrimination threshold for nicotine that was not impacted by the learning history. Further work on the importance of sex as a biological variable and how the complex interoceptive stimulus effects of nicotine can vary with training histories is needed.
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Abstract
The α7-type nicotinic acetylcholine receptor is one of the most unique and interesting of all the members of the cys-loop superfamily of ligand-gated ion channels. Since it was first identified initially as a binding site for α-bungarotoxin in mammalian brain and later as a functional homomeric receptor with relatively high calcium permeability, it has been pursued as a potential therapeutic target for numerous indications, from Alzheimer disease to asthma. In this review, we discuss the history and state of the art for targeting α7 receptors, beginning with subtype-selective agonists and the basic pharmacophore for the selective activation of α7 receptors. A key feature of α7 receptors is their rapid desensitization by standard "orthosteric" agonist, and we discuss insights into the conformational landscape of α7 receptors that has been gained by the development of ligands binding to allosteric sites. Some of these sites are targeted by positive allosteric modulators that have a wide range of effects on the activation profile of the receptors. Other sites are targeted by direct allosteric agonist or antagonists. We include a perspective on the potential importance of α7 receptors for metabotropic as well as ionotropic signaling. We outline the challenges that exist for future development of drugs to target this important receptor and approaches that may be considered to address those challenges. SIGNIFICANCE STATEMENT: The α7-type nicotinic acetylcholine receptor (nAChR) is acknowledged as a potentially important therapeutic target with functional properties associated with both ionotropic and metabotropic signaling. The functional properties of α7 nAChR can be regulated in diverse ways with the variety of orthosteric and allosteric ligands described in this review.
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Affiliation(s)
- Roger L Papke
- Departments of Pharmacology and Therapeutics (R.L.P) and Chemistry (N.A.H.), University of Florida, Gainesville, FL
| | - Nicole A Horenstein
- Departments of Pharmacology and Therapeutics (R.L.P) and Chemistry (N.A.H.), University of Florida, Gainesville, FL
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Bavo F, Pallavicini M, Appiani R, Bolchi C. Determinants for α4β2 vs. α3β4 Subtype Selectivity of Pyrrolidine-Based nAChRs Ligands: A Computational Perspective with Focus on Recent cryo-EM Receptor Structures. Molecules 2021; 26:molecules26123603. [PMID: 34204637 PMCID: PMC8231201 DOI: 10.3390/molecules26123603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 12/26/2022] Open
Abstract
The selectivity of α4β2 nAChR agonists over the α3β4 nicotinic receptor subtype, predominant in ganglia, primarily conditions their therapeutic range and it is still a complex and challenging issue for medicinal chemists and pharmacologists. Here, we investigate the determinants for such subtype selectivity in a series of more than forty α4β2 ligands we have previously reported, docking them into the structures of the two human subtypes, recently determined by cryo-electron microscopy. They are all pyrrolidine based analogues of the well-known α4β2 agonist N-methylprolinol pyridyl ether A-84543 and differ in the flexibility and pattern substitution of their aromatic portion. Indeed, the direct or water mediated interaction with hydrophilic residues of the relatively narrower β2 minus side through the elements decorating the aromatic ring and the stabilization of the latter by facing to the not conserved β2-Phe119 result as key distinctive features for the α4β2 affinity. Consistently, these compounds show, despite the structural similarity, very different α4β2 vs. α3β4 selectivities, from modest to very high, which relate to rigidity/extensibility degree of the portion containing the aromatic ring and to substitutions at the latter. Furthermore, the structural rationalization of the rat vs. human differences of α4β2 vs. α3β4 selectivity ratios is here proposed.
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Affiliation(s)
- Francesco Bavo
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Marco Pallavicini
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
| | - Rebecca Appiani
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
| | - Cristiano Bolchi
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
- Correspondence:
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12
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Wills L, Kenny PJ. Addiction-related neuroadaptations following chronic nicotine exposure. J Neurochem 2021; 157:1652-1673. [PMID: 33742685 DOI: 10.1111/jnc.15356] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 12/16/2022]
Abstract
The addiction-relevant molecular, cellular, and behavioral actions of nicotine are derived from its stimulatory effects on neuronal nicotinic acetylcholine receptors (nAChRs) in the central nervous system. nAChRs expressed by dopamine-containing neurons in the ventral midbrain, most notably in the ventral tegmental area (VTA), contribute to the reward-enhancing properties of nicotine that motivate the use of tobacco products. nAChRs are also expressed by neurons in brain circuits that regulate aversion. In particular, nAChRs expressed by neurons in the medial habenula (mHb) and the interpeduncular nucleus (IPn) to which the mHb almost exclusively projects regulate the "set-point" for nicotine aversion and control nicotine intake. Different nAChR subtypes are expressed in brain reward and aversion circuits and nicotine intake is titrated to maximally engage reward-enhancing nAChRs while minimizing the recruitment of aversion-promoting nAChRs. With repeated exposure to nicotine, reward- and aversion-related nAChRs and the brain circuits in which they are expressed undergo adaptations that influence whether tobacco use will transition from occasional to habitual. Genetic variation that influences the sensitivity of addiction-relevant brain circuits to the actions of nicotine also influence the propensity to develop habitual tobacco use. Here, we review some of the key advances in our understanding of the mechanisms by which nicotine acts on brain reward and aversion circuits and the adaptations that occur in these circuits that may drive addiction to nicotine-containing tobacco products.
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Affiliation(s)
- Lauren Wills
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
| | - Paul J Kenny
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
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Touchette JC, Moen JK, Robinson JM, Lee AM. Enhancement of alcohol aversion by the nicotinic acetylcholine receptor drug sazetidine-A. Addict Biol 2021; 26:e12908. [PMID: 32329567 DOI: 10.1111/adb.12908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 12/31/2022]
Abstract
The prevalence of alcohol use disorders (AUDs) has steadily increased in the United States over the last 30 years. Alcohol acts on multiple receptor systems including the nicotinic acetylcholine receptors (nAChRs), which are known to mediate alcohol consumption and reward. We previously reported that the preclinical drug sazetidine-A, a nAChR agonist and desensitizer, reduces alcohol consumption without affecting nicotine consumption in C57BL/6J mice. Here, we found that sazetidine-A enhances the expression of alcohol aversion without affecting the expression or acquisition of conditioned alcohol reward in C57BL/6J mice. Microinjection of sazetidine-A into the ventral midbrain targeting the ventral tegmental area (VTA) reduced binge alcohol consumption, implicating this region in mediating the effects of sazetidine-A. Furthermore, the sazetidine-A-induced reduction in alcohol consumption was mediated by non-α4 containing nAChRs, as sazetidine-A reduced binge alcohol consumption in both α4 knock-out and wild-type mice. Finally, we found that in mice pretreated with sazetidine-A, alcohol induced Fos transcript in Th-, but not Gad2-expressing neurons in the VTA as measured by increased Fos transcript expression. In summary, we find that sazetidine-A enhances the expression of alcohol aversion, which may underlie the reduction in alcohol consumption induced by sazetidine-A. Elucidating the identity of non-α4 nAChRs in alcohol aversion mechanisms will provide a better understanding the complex role of nAChRs in alcohol addiction and potentially reveal novel drug targets to treat AUDs.
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Affiliation(s)
| | - Janna K. Moen
- Graduate Program in Neuroscience University of Minnesota Minneapolis Minnesota USA
| | - Jenna M. Robinson
- Department of Pharmacology University of Minnesota Minneapolis Minnesota USA
| | - Anna M. Lee
- Department of Pharmacology University of Minnesota Minneapolis Minnesota USA
- Graduate Program in Neuroscience University of Minnesota Minneapolis Minnesota USA
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14
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Corrie LW, Stokes C, Wilkerson JL, Carroll FI, McMahon LR, Papke RL. Nicotinic Acetylcholine Receptor Accessory Subunits Determine the Activity Profile of Epibatidine Derivatives. Mol Pharmacol 2020; 98:328-342. [PMID: 32690626 DOI: 10.1124/molpharm.120.000037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 07/02/2020] [Indexed: 12/25/2022] Open
Abstract
Epibatidine is a potent analgetic agent with very high affinity for brain nicotinic acetylcholine receptors (nAChR). We determined the activity profiles of three epibatidine derivatives, RTI-36, RTI-76, and RTI-102, which have affinity for brain nAChR equivalent to that of epibatidine but reduced analgetic activity. RNAs coding for nAChR monomeric subunits and/or concatamers were injected into Xenopus oocytes to obtain receptors of defined subunit composition and stoichiometry. The epibatidine analogs produced protracted activation of high sensitivity (HS) α4- and α2-containing receptors with the stoichiometry of 2alpha:3beta subunits but not low sensitivity (LS) receptors with the reverse ratio of alpha and beta subunits. Although not strongly activated by the epibatidine analogs, LS α4- and α2-containing receptors were potently desensitized by the epibatidine analogs. In general, the responses of α4(2)β2(2)α5 and β3α4β2α6β2 receptors were similar to those of the HS α4β2 receptors. RTI-36, the analog closest in structure to epibatidine, was the most efficacious of the three compounds, also effectively activating α7 and α3β4 receptors, albeit with lower potency and less desensitizing effect. Although not the most efficacious agonist, RTI-76 was the most potent desensitizer of α4- and α2-containing receptors. RTI-102, a strong partial agonist for HS α4β2 receptors, was effectively an antagonist for LS α4β2 receptors. Our results highlight the importance of subunit stoichiometry and the presence or absence of specific accessory subunits for determining the activity of these drugs on brain nAChR, affecting the interpretation of in vivo studies since in most cases these structural details are not known. SIGNIFICANCE STATEMENT: Epibatidine and related compounds are potent ligands for the high-affinity nicotine receptors of the brain, which are therapeutic targets and mediators of nicotine addiction. Far from being a homogeneous population, these receptors are diverse in subunit composition and vary in subunit stoichiometry. We show the importance of these structural details for drug activity profiles, which present a challenge for the interpretation of in vivo experiments since conventional methods, such as in situ hybridization and immunohistochemistry, cannot illuminate these details.
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Affiliation(s)
- Lu Wenchi Corrie
- Department of Pharmacology and Therapeutics, College of Medicine (L.W.C., C.S., R.L.P.) and Department of Pharmacodynamics, College of Pharmacy, (J.L.W., L.R.M.), University of Florida, Gainesville, Florida; and Center for Drug Discovery, Research Triangle Institute, Durham, North Carolina (F.I.C.)
| | - Clare Stokes
- Department of Pharmacology and Therapeutics, College of Medicine (L.W.C., C.S., R.L.P.) and Department of Pharmacodynamics, College of Pharmacy, (J.L.W., L.R.M.), University of Florida, Gainesville, Florida; and Center for Drug Discovery, Research Triangle Institute, Durham, North Carolina (F.I.C.)
| | - Jenny L Wilkerson
- Department of Pharmacology and Therapeutics, College of Medicine (L.W.C., C.S., R.L.P.) and Department of Pharmacodynamics, College of Pharmacy, (J.L.W., L.R.M.), University of Florida, Gainesville, Florida; and Center for Drug Discovery, Research Triangle Institute, Durham, North Carolina (F.I.C.)
| | - F Ivy Carroll
- Department of Pharmacology and Therapeutics, College of Medicine (L.W.C., C.S., R.L.P.) and Department of Pharmacodynamics, College of Pharmacy, (J.L.W., L.R.M.), University of Florida, Gainesville, Florida; and Center for Drug Discovery, Research Triangle Institute, Durham, North Carolina (F.I.C.)
| | - Lance R McMahon
- Department of Pharmacology and Therapeutics, College of Medicine (L.W.C., C.S., R.L.P.) and Department of Pharmacodynamics, College of Pharmacy, (J.L.W., L.R.M.), University of Florida, Gainesville, Florida; and Center for Drug Discovery, Research Triangle Institute, Durham, North Carolina (F.I.C.)
| | - Roger L Papke
- Department of Pharmacology and Therapeutics, College of Medicine (L.W.C., C.S., R.L.P.) and Department of Pharmacodynamics, College of Pharmacy, (J.L.W., L.R.M.), University of Florida, Gainesville, Florida; and Center for Drug Discovery, Research Triangle Institute, Durham, North Carolina (F.I.C.)
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15
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Djemil S, Chen X, Zhang Z, Lee J, Rauf M, Pak DTS, Dzakpasu R. Activation of nicotinic acetylcholine receptors induces potentiation and synchronization within in vitro hippocampal networks. J Neurochem 2019; 153:468-484. [PMID: 31821553 DOI: 10.1111/jnc.14938] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 01/08/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are known to play a role in cognitive functions of the hippocampus, such as memory consolidation. Given that they conduct Ca2+ and are capable of regulating the release of glutamate and γ-aminobutyric acid (GABA) within the hippocampus, thereby shifting the excitatory-inhibitory ratio, we hypothesized that the activation of nAChRs will result in the potentiation of hippocampal networks and alter synchronization. We used nicotine as a tool to investigate the impact of activation of nAChRs on neuronal network dynamics in primary embryonic rat hippocampal cultures prepared from timed-pregnant Sprague-Dawley rats. We perturbed cultured hippocampal networks with increasing concentrations of bath-applied nicotine and performed network extracellular recordings of action potentials using a microelectrode array. We found that nicotine modulated network dynamics in a concentration-dependent manner; it enhanced firing of action potentials as well as facilitated bursting activity. In addition, we used pharmacological agents to determine the contributions of discrete nAChR subtypes to the observed network dynamics. We found that β4-containing nAChRs are necessary for the observed increases in spiking, bursting, and synchrony, while the activation of α7 nAChRs augments nicotine-mediated network potentiation but is not necessary for its manifestation. We also observed that antagonists of N-methyl-D-aspartate receptors (NMDARs) and group I metabotropic glutamate receptors (mGluRs) partially blocked the effects of nicotine. Furthermore, nicotine exposure promoted autophosphorylation of Ca2+ /calmodulin-dependent kinase II (CaMKII) and serine 831 phosphorylation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit GluA1. These results suggest that nicotinic receptors induce potentiation and synchronization of hippocampal networks and glutamatergic synaptic transmission. Findings from this work highlight the impact of cholinergic signaling in generating network-wide potentiation in the form of enhanced spiking and bursting dynamics that coincide with molecular correlates of memory such as increased phosphorylation of CaMKII and GluA1. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Sarra Djemil
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA
| | - Xin Chen
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Ziyue Zhang
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Jisoo Lee
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA
| | - Mikael Rauf
- Department of Human Science, Georgetown University Medical Center, Washington, DC, USA
| | - Daniel T S Pak
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA.,Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Rhonda Dzakpasu
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA.,Department of Physics, Georgetown University, Washington, DC, USA.,Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA
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16
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Dezfuli G, Olson TT, Martin LM, Keum Y, Siegars BA, Desai A, Uitz M, Sahibzada N, Gillis RA, Kellar KJ. α4β2 nicotinic acetylcholine receptors intrinsically influence body weight in mice. Neuropharmacology 2019; 166:107921. [PMID: 31881170 DOI: 10.1016/j.neuropharm.2019.107921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/26/2019] [Accepted: 12/20/2019] [Indexed: 11/29/2022]
Abstract
Desensitization of the nicotinic acetylcholine receptor (nAChR) containing the β2 subunit is a potentially critical mechanism underlying the body weight (BW) reducing effects of nicotine. The purpose of this study was a) to determine the α subunit(s) that partners with the β2 subunit to form the nAChR subtype that endogenously regulates energy balance and b) to probe the extent to which nAChR desensitization could be involved in the regulation of BW. We demonstrate that deletion of either the α4 or the β2, but not the α5, subunit of the nAChR suppresses weight gain in a sex-dependent manner. Furthermore, chronic treatment with the β2-selective nAChR competitive antagonist dihydro-β-erythroidine (DHβE) in mice fed a high-fat diet suppresses weight gain. These results indicate that heteromeric α4β2 nAChRs play a role as intrinsic regulators of energy balance and that desensitizing or inhibiting this nAChR is likely a relevant mechanism and thus could be a strategy for weight loss.
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Affiliation(s)
- Ghazaul Dezfuli
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Thao T Olson
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Lukas M Martin
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Youngshin Keum
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Byron A Siegars
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Anushka Desai
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Mia Uitz
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Niaz Sahibzada
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Richard A Gillis
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Kenneth J Kellar
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, D.C., USA.
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17
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Adeluyi A, Guerin L, Fisher ML, Galloway A, Cole RD, Chan SSL, Wyatt MD, Davis SW, Freeman LR, Ortinski PI, Turner JR. Microglia morphology and proinflammatory signaling in the nucleus accumbens during nicotine withdrawal. SCIENCE ADVANCES 2019; 5:eaax7031. [PMID: 31633029 PMCID: PMC6785260 DOI: 10.1126/sciadv.aax7031] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/14/2019] [Indexed: 05/07/2023]
Abstract
Smoking is the largest preventable cause of death and disease in the United States. However, <5% of quit attempts are successful, underscoring the urgent need for novel therapeutics. Microglia are one untapped therapeutic target. While previous studies have shown that microglia mediate both inflammatory responses in the brain and brain plasticity, little is known regarding their role in nicotine dependence and withdrawal phenotypes. Here, we examined microglial changes in the striatum-a mesolimbic region implicated in the rewarding effects of drugs and the affective disruptions occurring during withdrawal. We show that both nicotine and withdrawal induce microglial morphological changes; however, proinflammatory effects and anxiogenic behaviors were observed only during nicotine withdrawal. Pharmacological microglial depletion during withdrawal prevented these effects. These results define differential effects of nicotine and withdrawal on inflammatory signaling in the brain, laying the groundwork for development of future smoking cessation therapeutics.
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Affiliation(s)
- Adewale Adeluyi
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, USA
| | - Lindsey Guerin
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, USA
| | - Miranda L. Fisher
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, USA
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA
| | - Ashley Galloway
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Robert D. Cole
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
- Department of Neuroscience, University of Kentucky School of Medicine, Lexington, KY, USA
| | - Sherine S. L. Chan
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, USA
- Neuroene Therapeutics, Mt Pleasant, SC, USA
| | - Michael D. Wyatt
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, USA
| | | | - Linnea R. Freeman
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Pavel I. Ortinski
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
- Department of Neuroscience, University of Kentucky School of Medicine, Lexington, KY, USA
| | - Jill R. Turner
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, USA
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA
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18
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Mori D, Kimura H, Kawashima H, Yagi Y, Arimitsu K, Ono M, Saji H. Development of 99mTc radiolabeled A85380 derivatives targeting cerebral nicotinic acetylcholine receptor: Novel radiopharmaceutical ligand 99mTc-A-YN-IDA-C4. Bioorg Med Chem 2019; 27:4200-4210. [PMID: 31401009 DOI: 10.1016/j.bmc.2019.07.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 01/22/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels that have been implicated in higher brain functions. To elucidate the functional mechanisms underlying nAChRs and contribute significantly to development of drugs targeting neurological and neuropsychiatric diseases, non-invasive nuclear medical imaging can be used for evaluation. In addition, technetium-99m (99mTc) is a versatile radionuclide used clinically as a tracer in single-photon emission computed tomography. Because A85380 is known as a potent α4β2-nAChR agonist, we prepared A85380 derivatives labeled with 99mTc using a bifunctional chelate system. A computational scientific approach was used to design the probe efficiently. We used non-radioactive rhenium (Re) for a 99mTc analog and found that one of the derivatives, Re-A-YN-IDA-C4, exhibited high binding affinity at α4β2-nAChR in both the docking simulation (-19.3 kcal/mol) and binding assay (Ki = 0.4 ± 0.04 nM). Further, 99mTc-A-YN-IDA-C4 was synthesized using microwaves, and its properties were examined. Consequently, we found that 99mTc-A-YN-IDA-C4, with a structure optimized by using computational chemistry techniques, maintained affinity and selectivity for nAChR in vitro and possessed efficient characteristics as a nuclear medicine molecular imaging probe, demonstrated usefulness of computational scientific approach for molecular improvement strategy.
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Affiliation(s)
- Daisuke Mori
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hiroyuki Kimura
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan.
| | - Hidekazu Kawashima
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Radioisotope Research Center, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yusuke Yagi
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Kenji Arimitsu
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Masahiro Ono
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hideo Saji
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
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19
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Rezvani AH, Wells C, Slade S, Xiao Y, Kellar KJ, Levin ED. Oral sazetidine-A, a selective α4β2* nicotinic receptor desensitizing agent, reduces nicotine self-administration in rats. Pharmacol Biochem Behav 2019; 179:109-112. [PMID: 30794849 PMCID: PMC6570822 DOI: 10.1016/j.pbb.2019.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/26/2018] [Accepted: 02/18/2019] [Indexed: 10/27/2022]
Abstract
Sazetidine-A selectively desensitizes α4β2 nicotinic receptors and also has partial agonist effects. We have shown that subcutaneous acute and repeated injections as well as chronic infusions of sazetidine-A significantly reduce intravenous (IV) nicotine self-administration in rats. To further investigate the promise of sazetidine-A as a smoking cessation aid, it is important to determine sazetidine-A effects with oral administration and the time-effect function for its action on nicotine self-administration. Young adult female Sprague-Dawley rats were trained to self-administer IV nicotine at the benchmark dose of 0.03 mg/kg/infusion dose in an operant FR1 schedule in 45-min sessions. After five sessions of training, they were tested for the effects of acute oral doses of sazetidine-A (0, 0.3, 1 and 3 mg/kg) given 30 min before testing. To determine the time-effect function, these rats were administered 0 or 3 mg/kg of sazetidine-A 1, 2, 4 or 23 h before the onset of testing. Our previous study showed that with subcutaneous injections, only 3 mg/kg of sazetidine-A significantly reduced nicotine self-administration, however, with oral administration of sazetidine-A lower dose of 1 mg/kg was also effective in reducing nicotine intake. A similar effect was seen in the time-effect study with 3 mg/kg of oral sazetidine-A causing a significant reduction in nicotine self-administration across all the time points of 1, 2, 4 or 23 h after oral administration. These results advance the development of sazetidine-A as a possible aid for smoking cessation by showing effectiveness with oral administration and persistence of the effect over the course of a day.
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Affiliation(s)
- Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, USA
| | - Corinne Wells
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, USA
| | - Susan Slade
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, USA
| | - Yingxian Xiao
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, USA
| | - Kenneth J Kellar
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, USA
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, USA.
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20
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Levin ED, Rezvani AH, Wells C, Slade S, Yenugonda VM, Liu Y, Brown ML, Xiao Y, Kellar KJ. α4β2 Nicotinic receptor desensitizing compounds can decrease self-administration of cocaine and methamphetamine in rats. Eur J Pharmacol 2019; 845:1-7. [PMID: 30529197 PMCID: PMC6353686 DOI: 10.1016/j.ejphar.2018.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/03/2018] [Accepted: 12/05/2018] [Indexed: 02/08/2023]
Abstract
Sazetidine-A [6-(5(((S)-azetidine-2-yl)methoxy)pyridine-3-yl)hex-5-yn-1-ol] is a selective α4β2 nicotinic receptor desensitizing agent and partial agonist. Sazetidine-A has been shown in our previous studies to significantly reduce nicotine and alcohol self-administration in rats. The question arises whether sazetidine-A would reduce self-administration of other addictive drugs as well. Nicotinic receptors on the dopaminergic neurons in the ventral tegmental area play an important role in controlling the activity of these neurons and release of dopamine in the nucleus accumbens, which is critical mechanism for reinforcing value of drugs of abuse. Previously, we showed that the nonspecific nicotinic antagonist mecamylamine significantly reduces cocaine self-administration in rats. In this study, we acutely administered systemically sazetidine-A and two other selective α4β2 nicotinic receptor-desensitizing agents, VMY-2-95 and YL-2-203, to young adult female Sprague-Dawley rats and determined their effects on IV self-administration of cocaine and methamphetamine. Cocaine self-administration was significantly reduced by 0.3 mg/kg of sazetidine-A. In another set of rats, sazetidine-A (3 mg/kg) significantly reduced methamphetamine self-administration. VMY-2-95 significantly reduced both cocaine and methamphetamine self-administration with threshold effective doses of 3 and 0.3 mg/kg, respectively. In contrast, YL-2-203 did not significantly reduce cocaine self-administration at the same dose range and actually significantly increased cocaine self-administration at the 1 mg/kg dose. YL-2-203 (3 mg/kg) did significantly decrease methamphetamine self-administration. Sazetidine-A and VMY-2-95 are promising candidates to develop as new treatments to help addicts successfully overcome a variety of addictions including tobacco, alcohol as well as the stimulant drugs cocaine and methamphetamine.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA.
| | - Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Corinne Wells
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Susan Slade
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Venkata M Yenugonda
- Department of Translational Neurosciences and Neurotherapeutics, John Wayne Cancer Institute, 2200 Santa Monica Blvd, Santa Monica, CA 90404, USA
| | - Yong Liu
- Drug Discovery Program and Georgetown University School of Medicine, Washington DC 20057, USA
| | - Milton L Brown
- Drug Discovery Program and Georgetown University School of Medicine, Washington DC 20057, USA
| | - Yingxian Xiao
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington DC 20057, USA
| | - Kenneth J Kellar
- Drug Discovery Program and Georgetown University School of Medicine, Washington DC 20057, USA
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21
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Cippitelli A, Brunori G, Schoch J, Armishaw CJ, Wu J, Zaveri NT, Giulianotti MA, Welmaker GS, Toll L. Differential regulation of alcohol taking and seeking by antagonism at α4β2 and α3β4 nAChRs. Psychopharmacology (Berl) 2018; 235:1745-1757. [PMID: 29572652 PMCID: PMC5949259 DOI: 10.1007/s00213-018-4883-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/13/2018] [Indexed: 12/17/2022]
Abstract
RATIONALE Alcoholism is a serious public health problem throughout the world. Current pharmacotherapies for the treatment of this disorder are poorly effective. Preclinical and clinical findings point to nicotinic acetylcholine receptors (nAChRs) as a promising target for the development of novel and effective medications. Assuage Pharmaceuticals, in collaboration with Torrey Pines Institute for Molecular Studies, has discovered a new class of potent and selective α4β2 nAChR antagonists. OBJECTIVE Here, it was hypothesized that α4β2 nAChR antagonism is a viable approach for treatment of alcohol use disorders. RESULTS When tested in rats, one lead compound, AP-202, attenuated both operant alcohol and nicotine self-administration in a paradigm in which the two reinforcers were concurrently available. The conotoxin TP2212-59, a selective α3β4 nAChR antagonist, was only effective in reducing nicotine self-administration. AP-202 also reduced alcohol but not food responding when alcohol was presented as the only reinforcer, whereas the commercially available α4β2 nAChR antagonist dihydro-β-erythroidine failed to alter alcohol self-administration. AP-202 did not block relapse-like behavior induced by previously alcohol-associated stimuli or yohimbine stress. In a reinstatement paradigm, in which alcohol seeking was triggered by a nicotine challenge, a behavior successfully inhibited by the nonselective nAChR antagonist mecamylamine, AP-202 was not effective, while pretreatment with TP2212-59 abolished nicotine-induced reinstatement of alcohol seeking. CONCLUSIONS These findings suggest differential roles for α4β2 and α3β4 nAChR on alcohol taking and seeking with selective blockade of α4β2 nAChR being more implicated in modulating alcohol taking while selective blockade of α3β4 nAChR is involved in nicotine-induced alcohol seeking.
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Affiliation(s)
- Andrea Cippitelli
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL, 34987, USA.
| | - Gloria Brunori
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
| | - Jennifer Schoch
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
| | - Christopher J. Armishaw
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
| | - Jinhua Wu
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA,Assuage Pharmaceuticals, Inc., 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
| | - Nurulain T. Zaveri
- Astraea Therapeutics, LLC, 320 Logue Avenue, Mountain View, CA 94043, USA
| | - Marc A. Giulianotti
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA,Assuage Pharmaceuticals, Inc., 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
| | - Gregory S. Welmaker
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA,Assuage Pharmaceuticals, Inc., 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
| | - Lawrence Toll
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA,Assuage Pharmaceuticals, Inc., 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
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22
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Touchette JC, Maertens JJ, Mason MM, O'Rourke KY, Lee AM. The nicotinic receptor drug sazetidine-A reduces alcohol consumption in mice without affecting concurrent nicotine consumption. Neuropharmacology 2018; 133:63-74. [PMID: 29355641 PMCID: PMC5858984 DOI: 10.1016/j.neuropharm.2018.01.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 01/09/2018] [Accepted: 01/13/2018] [Indexed: 01/01/2023]
Abstract
Alcohol and nicotine addiction are frequently co-morbid. The nicotinic acetylcholine receptors (nAChRs) are critical for both alcohol and nicotine addiction mechanisms, since nAChR drugs that reduce nicotine consumption have been shown to also reduce alcohol consumption. Sazetidine-A, a pre-clinical nAChR drug with agonist and desensitizing effects at α4β2 and α7 nAChRs, has been reported to reduce alcohol consumption and nicotine self-administration in rats when administered at high doses. However, this effect has not been replicated in mice. In this study, we examined the effect of sazetidine-A on alcohol and nicotine consumption in male and female mice utilizing voluntary oral consumption procedures previously developed in our lab. We found that sazetidine-A (1 mg/kg, i.p) reduced overnight alcohol consumption, but did not affect nicotine consumption when presented either alone or concurrently with alcohol. Sazetidine-A did not reduce water or saccharin consumption at any dose tested. In a chronic co-consumption experiment in which either alcohol or nicotine was re-introduced after one week of forced abstinence, sazetidine-A attenuated post-abstinence consumption of alcohol but not nicotine. Sazetidine-A also significantly reduced alcohol consumption in an acute, binge drinking-in-the-dark procedure. Finally, we tested the effect of sazetidine-A on alcohol withdrawal, and found that sazetidine-A significantly reduced handling-induced convulsions during alcohol withdrawal. Collectively, these data suggest a novel role for the nAChR targets of sazetidine-A in specifically mediating alcohol consumption, separate from the involvement of nAChRs in mediating nicotine consumption. Delineation of this pathway may provide insight into novel therapies for the treatment of alcohol use disorders.
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Affiliation(s)
| | - Jamie J Maertens
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Margaret M Mason
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Kyu Y O'Rourke
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Anna M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA.
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23
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Differential effects of α4β2 nicotinic receptor antagonists and partial-agonists on contextual fear extinction in male C57BL/6 mice. Psychopharmacology (Berl) 2018; 235:1211-1219. [PMID: 29383396 PMCID: PMC5871575 DOI: 10.1007/s00213-018-4837-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/19/2018] [Indexed: 02/06/2023]
Abstract
RATIONALE Numerous studies have attributed the psychopathology of post-traumatic stress disorder (PTSD) to maladaptive behavioral responses such as an inability to extinguish fear. While exposure therapies are mostly effective in treating these disorders by enhancing extinction learning, relapse of PTSD symptoms is common. Although several studies indicated a role for cholinergic transmission and nicotinic acetylcholine receptors (nAChRs) in anxiety and stress disorder symptomatology, very little is known about the specific contribution of nAChRs to fear extinction OBJECTIVES: In the present study, we examined the effects of inhibition and desensitization of α4β2 nAChRs via a full antagonist (Dihydro-beta-erythroidine (DhβE)) and two α4β2 nAChR partial-agonists (varenicline and sazetidine-A) on contextual fear extinction, locomotor activity, and spontaneous recovery of contextual fear in mice. METHODS We trained and tested the subjects in a contextual fear extinction as well as an open field paradigm and spontaneous recovery following injections of DhβE, varenicline, and sazetidine-A. RESULTS Our results demonstrated that lower doses of DhβE (1 mg/kg) and sazetidine-A (0.01 mg/kg) enhanced contextual fear extinction whereas higher doses of varenicline (0.1 mg/kg) and sazetidine-A (0.1 mg/kg) resulted in impaired contextual fear extinction. However, the higher dose of sazetidine-A (0.1 mg/kg) decreased locomotor activity, which may contribute to increased freezing response observed during fear extinction. Finally, we found that the low dose of DhβE, but not sazetidine-A, also decreased spontaneous recovery of contextual fear following fear extinction. CONCLUSIONS Overall, these results suggest that inhibition and desensitization of α4β2 nAChRs enhance extinction of contextual fear memories. This suggests that modulation of α4β2 nAChRs may be employed as an alternative pharmacological strategy to aid exposure therapies associated with PTSD by augmenting contextual fear extinction processes.
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24
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Kiguchi N, Kobayashi D, Saika F, Matsuzaki S, Kishioka S. Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury. J Neuroinflammation 2018; 15:96. [PMID: 29587798 PMCID: PMC5872578 DOI: 10.1186/s12974-018-1133-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 03/15/2018] [Indexed: 12/24/2022] Open
Abstract
Background Neuro–immune interaction underlies chronic neuroinflammation and aberrant sensory processing resulting in neuropathic pain. Despite the pathological significance of both neuroinflammation-driven peripheral sensitization and spinal sensitization, the functional relationship between these two distinct events has not been understood. Methods In this study, we determined whether inhibition of inflammatory macrophages by administration of α4β2 nicotinic acetylcholine receptor (nAChR) agonists improves neuropathic pain and affects microglial activation in the spinal dorsal horn (SDH) in mice following partial sciatic nerve ligation (PSL). Expression levels of neuroinflammatory molecules were evaluated by RT-qPCR and immunohistochemistry, and PSL-induced mechanical allodynia was defined by the von Frey test. Results Flow cytometry revealed that CD11b+ F4/80+ macrophages were accumulated in the injured sciatic nerve (SCN) after PSL. TC-2559, a full agonist for α4β2 nAChR, suppressed the upregulation of interleukin-1β (IL-1β) in the injured SCN after PSL and attenuated lipopolysaccharide-induced upregulation of IL-1β in cultured macrophages. Systemic (subcutaneous, s.c.) administration of TC-2559 during either the early (days 0–3) or middle/late (days 7–10) phase of PSL improved mechanical allodynia. Moreover, local (perineural, p.n.) administration of TC-2559 and sazetidine A, a partial agonist for α4β2 nAChR, during either the early or middle phase of PSL improved mechanical allodynia. However, p.n. administration of sazetidine A during the late (days 21–24) phase did not show the attenuating effect, whereas p.n. administration of TC-2559 during this phase relieved mechanical allodynia. Most importantly, p.n. administration of TC-2559 significantly suppressed morphological activation of Iba1+ microglia and decreased the upregulation of inflammatory microglia-dominant molecules, such as CD68, interferon regulatory factor 5, and IL-1β in the SDH after PSL. Conclusion These findings support the notion that pharmacological inhibition of inflammatory macrophages using an α4β2 nAChR agonist exhibit a wide therapeutic window on neuropathic pain after nerve injury, and it could be nominated as a novel pharmacotherapy to relieve intractable pain. Electronic supplementary material The online version of this article (10.1186/s12974-018-1133-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Norikazu Kiguchi
- Department of Pharmacology, Wakayama Medical University, 811-1 Kimiidera, Wakayama city, Wakayama, 641-0012, Japan.
| | - Daichi Kobayashi
- Department of Pharmacology, Wakayama Medical University, 811-1 Kimiidera, Wakayama city, Wakayama, 641-0012, Japan
| | - Fumihiro Saika
- Department of Pharmacology, Wakayama Medical University, 811-1 Kimiidera, Wakayama city, Wakayama, 641-0012, Japan
| | - Shinsuke Matsuzaki
- Department of Pharmacology, Wakayama Medical University, 811-1 Kimiidera, Wakayama city, Wakayama, 641-0012, Japan
| | - Shiroh Kishioka
- Department of Pharmacology, Wakayama Medical University, 811-1 Kimiidera, Wakayama city, Wakayama, 641-0012, Japan
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25
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Levin ED, Wells C, Slade S, Rezvani AH. Mutually augmenting interactions of dextromethorphan and sazetidine-A for reducing nicotine self-administration in rats. Pharmacol Biochem Behav 2018; 166:42-47. [PMID: 29407477 PMCID: PMC5836513 DOI: 10.1016/j.pbb.2018.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/28/2018] [Accepted: 01/29/2018] [Indexed: 12/27/2022]
Abstract
A variety of nicotinic drug treatments have been found to decrease nicotine self-administration. However, interactions of drugs affecting different nicotinic receptor subtypes have not been much investigated. This study investigated the interactions between dextromethorphan, which blocks nicotinic α3β2 receptors as well as a variety of other receptors with sazetidine-A which is a potent and selective α4β2 nicotinic receptor partial agonist with desensitizing properties. This interaction was compared with dextromethorphan combination treatment with mecamylamine, which is a nonspecific nicotinic channel blocker. Co-administration of dextromethorphan (either 0.5 or 5 mg/kg) and lower dose of sazetidine-A (0.3 mg/kg) caused a significant reduction in nicotine SA. With regard to food-motivated responding, 3 mg/kg of sazetidine-A given alone caused a significant decrease in food intake. However, the lower 0.3 mg/kg sazetidine-A dose did not significantly affect food-motivated responding even when given in combination with the higher 5 mg/kg dextromethorphan dose which itself caused a significant decrease in food motivated responding. Interestingly, this higher dextromethorphan dose significantly attenuated the decrease in food motivated responding caused by 3 mg/kg of sazetidine-A. Locomotor activity was increased by the lower 0.3 mg/kg sazetidine-A dose and decreased by the 5 mg/kg dextromethorphan dose. Mecamylamine at the doses (0.1 and 1 mg/kg) did not affect nicotine SA, but at 1 mg/kg significantly decreased food-motivated responding. None of the mecamylamine doses augmented the effect of dextromethorphan in reducing nicotine self-administration. These studies showed that the combination of dextromethorphan and sazetidine-A had mutually potentiating effects, which could provide a better efficacy for promoting smoking cessation, however the strength of the interactions was fairly modest.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA.
| | - Corrine Wells
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Susan Slade
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
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26
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Hone AJ, McIntosh JM. Nicotinic acetylcholine receptors in neuropathic and inflammatory pain. FEBS Lett 2017; 592:1045-1062. [PMID: 29030971 DOI: 10.1002/1873-3468.12884] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/22/2017] [Accepted: 10/05/2017] [Indexed: 01/11/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are actively being investigated as therapeutic targets for the treatment of pain and inflammation, but despite more than 30 years of research, there are currently no FDA-approved analgesics that are specific for these receptors. Much of the initial research effort focused on the α4β2 nAChR subtype, but more recently, additional subtypes have been identified as promising new leads and include α6β4, α7, and α9-containing nAChRs. This Review will focus on the distribution of these nAChRs in the cell types involved in neuropathic pain and inflammation and the activity of currently available nicotinic ligands.
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Affiliation(s)
- Arik J Hone
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT, USA.,Department of Psychiatry, University of Utah, Salt Lake City, UT, USA.,George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA
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27
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Stojakovic A, Espinosa EP, Farhad OT, Lutfy K. Effects of nicotine on homeostatic and hedonic components of food intake. J Endocrinol 2017; 235:R13-R31. [PMID: 28814527 PMCID: PMC5578410 DOI: 10.1530/joe-17-0166] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 07/17/2017] [Indexed: 12/30/2022]
Abstract
Chronic tobacco use leads to nicotine addiction that is characterized by exaggerated urges to use the drug despite the accompanying negative health and socioeconomic burdens. Interestingly, nicotine users are found to be leaner than the general population. Review of the existing literature revealed that nicotine affects energy homeostasis and food consumption via altering the activity of neurons containing orexigenic and anorexigenic peptides in the brain. Hypothalamus is one of the critical brain areas that regulates energy balance via the action of these neuropeptides. The equilibrium between these two groups of peptides can be shifted by nicotine leading to decreased food intake and weight loss. The aim of this article is to review the existing literature on the effect of nicotine on food intake and energy homeostasis and report on the changes that nicotine brings about in the level of these peptides and their receptors that may explain changes in food intake and body weight induced by nicotine. Furthermore, we review the effect of nicotine on the hedonic aspect of food intake. Finally, we discuss the involvement of different subtypes of nicotinic acetylcholine receptors in the regulatory action of nicotine on food intake and energy homeostasis.
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Affiliation(s)
- Andrea Stojakovic
- Department of Pharmaceutical SciencesCollege of Pharmacy, Western University of Health Sciences, Pomona, California, USA
- Mitochondrial Neurobiology and Therapeutics LaboratoryMayo Clinic, Rochester, Minnesota, USA
| | - Enma P Espinosa
- Department of Pharmaceutical SciencesCollege of Pharmacy, Western University of Health Sciences, Pomona, California, USA
- Faculty of MedicineSchool of Clinica Biochemistry, Pontifical Catholic University of Ecuador (PUCE), Quito, Ecuador
| | - Osman T Farhad
- Department of Pharmaceutical SciencesCollege of Pharmacy, Western University of Health Sciences, Pomona, California, USA
| | - Kabirullah Lutfy
- Department of Pharmaceutical SciencesCollege of Pharmacy, Western University of Health Sciences, Pomona, California, USA
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28
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Rezvani AH, Slade S, Wells C, Yenugonda VM, Liu Y, Brown ML, Xiao Y, Kellar KJ, Levin ED. Differential efficacies of the nicotinic α4β2 desensitizing agents in reducing nicotine self-administration in female rats. Psychopharmacology (Berl) 2017; 234:2517-2523. [PMID: 28555315 DOI: 10.1007/s00213-017-4641-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 04/26/2017] [Indexed: 01/18/2023]
Abstract
RATIONALE AND OBJECTIVES Desensitization of neuronal nicotinic acetylcholine receptors holds promise as an effective treatment of tobacco addiction. Previously, we found that sazetidine-A (Saz-A), which selectively desensitizes α4β2 nicotinic receptors, significantly decreased intravenous (IV) nicotine self-administration (SA) in rats with an effective dose of 3 mg/kg in acute and repeated injection studies. We also found that chronic infusions of Saz-A at doses of 2 and 6 mg/kg/day significantly reduced nicotine SA in rats. In continuing studies, we have characterized other Saz-A analogs, YL-2-203 and VMY-2-95, to determine their efficacies in reducing nicotine SA in rats. METHODS Young adult female Sprague-Dawley rats were fitted with IV catheters and were trained for nicotine SA (0.03 mg/kg/infusion) on a fixed ratio 1 schedule for ten sessions. The same rats were also implanted subcutaneously with osmotic minipumps to continually deliver 2 or 6 mg/kg body weight YL-2-203, VMY-2-95, or saline for four consecutive weeks. RESULTS Chronic administration of VMY-2-95 at doses of 2 and 6 mg/kg/day caused significant (p < 0.01) decreases in nicotine SA over the 2 weeks of continued nicotine SA and for the 1-week period of resumed access after a week of enforced abstinence, whereas chronic administration of YL-2-203 at the same doses was not found to be effective. CONCLUSIONS These studies, together with our previous studies of Saz-A, revealed a spectrum of efficacies for these α4β2 nicotinic receptor desensitizing agents and provide a path forward for the most effective compounds to be further developed as possible aids to smoking cessation.
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Affiliation(s)
- Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC, 27710, USA.
| | - Susan Slade
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC, 27710, USA
| | - Corinne Wells
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC, 27710, USA
| | - Venkata M Yenugonda
- Drug Discovery Program, Georgetown University School of Medicine, Washington, DC, 20057, USA
| | - Yong Liu
- Drug Discovery Program, Georgetown University School of Medicine, Washington, DC, 20057, USA
| | - Milton L Brown
- Drug Discovery Program, Georgetown University School of Medicine, Washington, DC, 20057, USA
| | - Yingxian Xiao
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, 20057, USA
| | - Kenneth J Kellar
- Drug Discovery Program, Georgetown University School of Medicine, Washington, DC, 20057, USA
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 104790, Durham, NC, 27710, USA
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29
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Axen SD, Huang XP, Cáceres EL, Gendelev L, Roth BL, Keiser MJ. A Simple Representation of Three-Dimensional Molecular Structure. J Med Chem 2017; 60:7393-7409. [PMID: 28731335 DOI: 10.1021/acs.jmedchem.7b00696] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Statistical and machine learning approaches predict drug-to-target relationships from 2D small-molecule topology patterns. One might expect 3D information to improve these calculations. Here we apply the logic of the extended connectivity fingerprint (ECFP) to develop a rapid, alignment-invariant 3D representation of molecular conformers, the extended three-dimensional fingerprint (E3FP). By integrating E3FP with the similarity ensemble approach (SEA), we achieve higher precision-recall performance relative to SEA with ECFP on ChEMBL20 and equivalent receiver operating characteristic performance. We identify classes of molecules for which E3FP is a better predictor of similarity in bioactivity than is ECFP. Finally, we report novel drug-to-target binding predictions inaccessible by 2D fingerprints and confirm three of them experimentally with ligand efficiencies from 0.442-0.637 kcal/mol/heavy atom.
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Affiliation(s)
- Seth D Axen
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco , 675 Nelson Rising Lane NS 416A, San Francisco, California 94143, United States
| | - Xi-Ping Huang
- Department of Pharmacology, University of North Carolina School of Medicine , Chapel Hill, North Carolina 27599, United States.,National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Elena L Cáceres
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco , 675 Nelson Rising Lane NS 416A, San Francisco, California 94143, United States.,Department of Pharmaceutical Chemistry, Institute for Neurodegenerative Diseases, and Institute for Computational Health Sciences, University of California, San Francisco , 675 Nelson Rising Lane NS 416A, San Francisco, California 94143, United States
| | - Leo Gendelev
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco , 675 Nelson Rising Lane NS 416A, San Francisco, California 94143, United States.,Department of Pharmaceutical Chemistry, Institute for Neurodegenerative Diseases, and Institute for Computational Health Sciences, University of California, San Francisco , 675 Nelson Rising Lane NS 416A, San Francisco, California 94143, United States
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine , Chapel Hill, North Carolina 27599, United States.,National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), University of North Carolina , Chapel Hill, North Carolina 27599, United States.,Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Michael J Keiser
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco , 675 Nelson Rising Lane NS 416A, San Francisco, California 94143, United States.,Department of Pharmaceutical Chemistry, Institute for Neurodegenerative Diseases, and Institute for Computational Health Sciences, University of California, San Francisco , 675 Nelson Rising Lane NS 416A, San Francisco, California 94143, United States
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30
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DeDominicis KE, Sahibzada N, Olson TT, Xiao Y, Wolfe BB, Kellar KJ, Yasuda RP. The ( α4) 3( β2) 2 Stoichiometry of the Nicotinic Acetylcholine Receptor Predominates in the Rat Motor Cortex. Mol Pharmacol 2017; 92:327-337. [PMID: 28698187 DOI: 10.1124/mol.116.106880] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 07/06/2017] [Indexed: 01/28/2023] Open
Abstract
The α4β2 nicotinic acetylcholine receptor (nAChR) is important in central nervous system physiology and in mediating several of the pharmacological effects of nicotine on cognition, attention, and affective states. It is also the likely receptor that mediates nicotine addiction. This receptor assembles in two distinct stoichiometries: (α4)2(β2)3 and (α4)3(β2)2, which are referred to as high-sensitivity (HS) and low-sensitivity (LS) nAChRs, respectively, based on a difference in the potency of acetylcholine to activate them. The physiologic and pharmacological differences between these two receptor subtypes have been described in heterologous expression systems. However, the presence of each stoichiometry in native tissue currently remains unknown. In this study, different ratios of rat α4 and β2 subunit cDNA were transfected into human embryonic kidney 293 cells to create a novel model system of HS and LS α4β2 nAChRs expressed in a mammalian cell line. The HS and LS nAChRs were characterized through pharmacological and biochemical methods. Isolation of surface proteins revealed higher amounts of α4 or β2 subunits in the LS or HS nAChR populations, respectively. In addition, sazetidine-A displayed different efficacies in activating these two receptor stoichiometries. Using this model system, a neurophysiological "two-concentration" acetylcholine or carbachol paradigm was developed and validated to determine α4/β2 subunit stoichiometry. This paradigm was then used in layers I-IV of slices of the rat motor cortex to determine the percent contribution of HS and LS α4β2 receptors in this brain region. We report that the majority of α4β2 nAChRs in this brain region possess a stoichiometry of the (α4)3(β2)2 LS subtype.
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Affiliation(s)
- Kristen E DeDominicis
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC
| | - Niaz Sahibzada
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC
| | - Thao T Olson
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC
| | - Yingxian Xiao
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC
| | - Barry B Wolfe
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC
| | - Kenneth J Kellar
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC
| | - Robert P Yasuda
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC
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31
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LeSage MG, Staley M, Muelken P, Smethells JR, Stepanov I, Vogel RI, Pentel PR, Harris AC. Abuse liability assessment of an e-cigarette refill liquid using intracranial self-stimulation and self-administration models in rats. Drug Alcohol Depend 2016; 168:76-88. [PMID: 27627814 PMCID: PMC5257285 DOI: 10.1016/j.drugalcdep.2016.08.628] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/14/2016] [Accepted: 08/22/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND The popularity of electronic cigarettes (ECs) has increased dramatically despite their unknown health consequences. Because the abuse liability of ECs is one of the leading concerns of the Food and Drug Administration (FDA), models to assess it are urgently needed to inform FDA regulatory decisions regarding these products. The purpose of this study was to assess the relative abuse liability of an EC liquid compared to nicotine alone in rats. Because this EC liquid contains non-nicotine constituents that may enhance its abuse liability, we hypothesized that it would have greater abuse liability than nicotine alone. METHODS Nicotine alone and nicotine dose-equivalent concentrations of EC liquid were compared in terms of their acute effects on intracranial self-stimulation (ICSS) thresholds, acquisition of self-administration, reinforcing efficacy (i.e., elasticity of demand), blockade of these behavioral effects by mecamylamine, nicotine pharmacokinetics and nicotinic acetylcholine receptor binding and activation. RESULTS There were no significant differences between formulations on any measure, except that EC liquid produced less of an elevation in ICSS thresholds at high nicotine doses. CONCLUSIONS Collectively, these findings suggest that the relative abuse liability of this EC liquid is similar to that of nicotine alone in terms of its reinforcing and reinforcement-enhancing effects, but that it may have less aversive/anhedonic effects at high doses. The present methods may be useful for assessing the abuse liability of other ECs to inform potential FDA regulation of those products.
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Affiliation(s)
- MG LeSage
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota, Minneapolis, MN,Department of Psychology, University of Minnesota, Minneapolis, MN, 55455
| | - M Staley
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN
| | - P Muelken
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN
| | - JR Smethells
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Psychiatry, University of Minnesota, Minneapolis, MN, 55455
| | - I Stepanov
- Masonic Cancer, Center University of Minnesota, Minneapolis, MN
| | - RI Vogel
- Masonic Cancer Center Biostatistics and Bioinformatics Core ,University of Minnesota Minneapolis, MN
| | - PR Pentel
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota, Minneapolis, MN
| | - AC Harris
- Department of Medicine, Minneapolis Medical Research Foundation, Minneapolis, MN,Department of Medicine, University of Minnesota, Minneapolis, MN,Department of Psychology, University of Minnesota, Minneapolis, MN, 55455
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32
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Bolchi C, Bavo F, Fumagalli L, Gotti C, Fasoli F, Moretti M, Pallavicini M. Novel 5-substituted 3-hydroxyphenyl and 3-nitrophenyl ethers of S-prolinol as α4β2-nicotinic acetylcholine receptor ligands. Bioorg Med Chem Lett 2016; 26:5613-5617. [PMID: 27818109 DOI: 10.1016/j.bmcl.2016.10.078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 10/20/2022]
Abstract
A series of 3-nitrophenyl and 3-hydroxyphenyl ethers of (S)-N-methylprolinol bearing bulky and lipophilic substituents at phenyl C5 were tested for affinity at α4β2 and α3β4 nAChRs. The two phenyl ethers 5-substituted with 6-hydroxy-1-hexynyl showed high α4β2 affinity and significantly increased α4β2/α3β4 selectivity compared to the respective unsubstituted parent compounds. Within the two series of novel phenyl ethers, we observed parallel shifts in affinity and, furthermore, the increase in α4β2/α3β4 selectivity resulting from the hydroxyalkynyl substitution parallels that reported for the same modification at the 3-pyridyl ether of (S)-N-methylprolinol (A-84543), a well-known potent α4β2 agonist. On the basis of these results, our nitrophenyl and hydroxyphenyl prolinol ethers can be considered bioisosteres of the pyridyl ether A-84543 and lead compounds candidable to analogous optimization processes.
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Affiliation(s)
- Cristiano Bolchi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133 Milano, Italy
| | - Francesco Bavo
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133 Milano, Italy
| | - Laura Fumagalli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133 Milano, Italy
| | - Cecilia Gotti
- CNR, Istituto di Neuroscienze, Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via Vanvitelli 32, I-20129 Milano, Italy
| | - Francesca Fasoli
- CNR, Istituto di Neuroscienze, Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via Vanvitelli 32, I-20129 Milano, Italy
| | - Milena Moretti
- CNR, Istituto di Neuroscienze, Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via Vanvitelli 32, I-20129 Milano, Italy
| | - Marco Pallavicini
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133 Milano, Italy.
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Bolchi C, Bavo F, Gotti C, Fumagalli L, Fasoli F, Binda M, Mucchietto V, Sciaccaluga M, Plutino S, Fucile S, Pallavicini M. From pyrrolidinyl-benzodioxane to pyrrolidinyl-pyridodioxanes, or from unselective antagonism to selective partial agonism at α4β2 nicotinic acetylcholine receptor. Eur J Med Chem 2016; 125:1132-1144. [PMID: 27810599 DOI: 10.1016/j.ejmech.2016.10.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 12/14/2022]
Abstract
Each of the four aromatic -CH= of (S,R)-2-pyrrolidinyl-1,4-benzodioxane [(S,R)-6] and of its epimer at the dioxane stereocenter (S,S)-6, previously reported as α4β2 nAChR ligands, was replaced with nitrogen. The resulting four diastereoisomeric pairs of pyrrolidinyl-pyridodioxanes were studied for the nicotinic affinity and activity at α4β2, α3β4 and α7 nAChR subtypes and compared to their common carbaisostere. It turned out that such isosteric substitutions are highly detrimental, but with the important exception of the S,R stereoisomer of the pyrrolidinyl-pyridodioxane with the pyridine nitrogen adjacent to the dioxane and seven atoms distant from the pyrrolidine nitrogen. Indeed, this stereo/regioisomer not only maintained the α4β2 affinity of [(S,R)-6], but also greatly improved in selectivity over the α3β4 and α7 subtypes and, most importantly, exhibited a highly selective α4β2 partial agonism. The finding that [(S,R)-6] is, instead, an unselective α4β2 antagonist indicates that the benzodioxane substructure confers affinity for the α4β2 nAChR binding site, but activation of this receptor subtype needs benzodioxane functionalization under strict steric requirements, such as the previously reported 7-OH substitution or the present isosteric modification.
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Affiliation(s)
- Cristiano Bolchi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133, Milano, Italy
| | - Francesco Bavo
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133, Milano, Italy
| | - Cecilia Gotti
- CNR, Istituto di Neuroscienze, and Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via Vanvitelli 32, Milano, I-20129, Italy
| | - Laura Fumagalli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133, Milano, Italy
| | - Francesca Fasoli
- CNR, Istituto di Neuroscienze, and Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via Vanvitelli 32, Milano, I-20129, Italy
| | - Matteo Binda
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133, Milano, Italy
| | - Vanessa Mucchietto
- CNR, Istituto di Neuroscienze, and Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via Vanvitelli 32, Milano, I-20129, Italy
| | - Miriam Sciaccaluga
- I.R.C.C.S. Neuromed, Istituto Neurologico Mediterraneo, via Atinese 18, I-86077, Pozzilli (Isernia), Italy
| | - Simona Plutino
- Dipartimento di Fisiologia e Farmacologia, Università di Roma La Sapienza, Piazzale Moro 5, 00185 Roma, Italy
| | - Sergio Fucile
- I.R.C.C.S. Neuromed, Istituto Neurologico Mediterraneo, via Atinese 18, I-86077, Pozzilli (Isernia), Italy; Dipartimento di Fisiologia e Farmacologia, Università di Roma La Sapienza, Piazzale Moro 5, 00185 Roma, Italy
| | - Marco Pallavicini
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via Mangiagalli 25, I-20133, Milano, Italy.
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Slater CA, Jackson A, Muldoon PP, Dawson A, O'Brien M, Soll LG, Abdullah R, Carroll FI, Tapper AR, Miles MF, Banks ML, Bettinger JC, Damaj IM. Nicotine Enhances the Hypnotic and Hypothermic Effects of Alcohol in the Mouse. Alcohol Clin Exp Res 2016; 40:62-72. [PMID: 26727524 DOI: 10.1111/acer.12918] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/28/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND Ethanol (EtOH) and nicotine abuse are 2 leading causes of preventable mortality in the world, but little is known about the pharmacological mechanisms mediating co-abuse. Few studies have examined the interaction of the acute effects of EtOH and nicotine. Here, we examine the effects of nicotine administration on the duration of EtOH-induced loss of righting reflex (LORR) and characterize the nature of their pharmacological interactions in C57BL/6J mice. METHODS We assessed the effects of EtOH and nicotine and the nature of their interaction in the LORR test using isobolographic analysis after acute injection in C57BL/6J male mice. Next, we examined the importance of receptor efficacy using nicotinic partial agonists varenicline and sazetidine. We evaluated the involvement of major nicotinic acetylcholine receptor (nAChR) subtypes using nicotinic antagonist mecamylamine and nicotinic α4- and α7-knockout mice. The selectivity of nicotine's actions on EtOH-induced LORR was examined by testing nicotine's effects on the hypnotic properties of ketamine and pentobarbital. We also assessed the development of tolerance after repeated nicotine exposure. Last, we assessed whether the effects of nicotine on EtOH-induced LORR extend to hypothermia and EtOH intake in the drinking in the dark (DID) paradigm. RESULTS We found that acute nicotine injection enhances EtOH's hypnotic effects in a synergistic manner and that receptor efficacy plays an important role in this interaction. Furthermore, tolerance developed to the enhancement of EtOH's hypnotic effects by nicotine after repeated exposure of the drug. α4* and α7 nAChRs seem to play an important role in nicotine-EtOH interaction in the LORR test. In addition, the magnitude of EtOH-induced LORR enhancement by nicotine was more pronounced in C57BL/6J than DBA/2J mice. Furthermore, acute nicotine enhanced ketamine and pentobarbital hypnotic effects in the mouse. Finally, nicotine enhanced EtOH-induced hypothermia but decreased EtOH intake in the DID test. CONCLUSIONS Our results demonstrate that nicotine synergistically enhances EtOH-induced LORR in the mouse.
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Affiliation(s)
- Cassandra A Slater
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Asti Jackson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Pretal P Muldoon
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Anton Dawson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Megan O'Brien
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Lindsey G Soll
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Rehab Abdullah
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - F Ivy Carroll
- Center for Organic and Medicinal Chemistry, Research Triangle Institute, Research Triangle Park, North Carolina
| | - Andrew R Tapper
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Michael F Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Imad M Damaj
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Fox-Loe AM, Dwoskin LP, Richards CI. Nicotinic Acetylcholine Receptors as Targets for Tobacco Cessation Therapeutics: Cutting-Edge Methodologies to Understand Receptor Assembly and Trafficking. NEUROMETHODS 2016; 117:119-132. [PMID: 28025590 DOI: 10.1007/978-1-4939-3768-4_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Tobacco dependence is a chronic relapsing disorder and nicotine, the primary alkaloid in tobacco, acts at nicotinic receptors to stimulate dopamine release in brain, which is responsible for the reinforcing properties of nicotine, leading to addiction. Although the majority of tobacco users express the desire to quit, only a small percentage of those attempting to quit are successful using the currently available pharmacotherapies. Nicotine upregulates the number of specific nicotinic receptors on the neuronal cell surface. An increase in receptor trafficking or preferential stoichiometric assembly of receptor subunits involves changes in assembly, endoplasmic reticulum export, vesicle transport, decreased degradation, desensitization, enhanced maturation of functional pentamers, and pharmacological chaperoning. Understanding these changes on a mechanistic level is important to the development of nicotinic receptors as drug targets. For this reason, cutting-edge methodologies are being developed and employed to pinpoint distinct changes in localization, assembly, export, vesicle trafficking, and stoichiometry in order to further understand the physiology of these receptors and to evaluate the action of novel therapeutics for smoking cessation.
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Dezfuli G, Kellar KJ, Dretchen KL, Tizabi Y, Sahibzada N, Gillis RA. Evidence for the role of β2* nAChR desensitization in regulating body weight in obese mice. Neuropharmacology 2016; 110:165-174. [PMID: 27444741 DOI: 10.1016/j.neuropharm.2016.07.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 07/15/2016] [Accepted: 07/16/2016] [Indexed: 12/24/2022]
Abstract
Nicotine's effect on food intake and body weight has been well documented; however, the relevant receptors underlying these effects have not been firmly established. The purpose of the present study was to: (1) identify the nicotinic acetylcholine receptor (nAChR) subtype involved in food intake and body weight; (2) establish whether food intake and body weight reduction produced by nicotinic drugs are due to activation or desensitization of nAChRs; and, (3) assess the role of the melanocortin system in nicotinic drug effects on food intake and body weight. To identify the nAChR, we tested the effect of sazetidine-A (SAZ-A), a relatively selective ligand of β2-containing nAChRs, on food intake and body weight in obese mice. SAZ-A (3 mg/kg; SC) administered twice-daily significantly decreased food intake and body weight. To assess whether these effects involved desensitization, SAZ-A was administered to non-obese mice via osmotic pump, which, due to its slow sustained drug delivery method, causes prolonged desensitization. SAZ-A via osmotic pump delivery significantly decreased the gain in body weight and reduced food intake. In contrast, body weight was unaffected by SAZ-A in β2(-/-) mice or in mice lacking the melanocortin 4 receptor (MC4R). These results indicate that β2 containing nAChRs are essential to SAZ-A's inhibitory effect on body weight and food intake and engage the melanocortin system.
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Affiliation(s)
- Ghazaul Dezfuli
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, D.C., USA
| | - Kenneth J Kellar
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Kenneth L Dretchen
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Yousef Tizabi
- Department of Pharmacology, College of Medicine, Howard University, Washington, D.C., USA
| | - Niaz Sahibzada
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA.
| | - Richard A Gillis
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA.
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Manetti D, Bellucci C, Dei S, Teodori E, Varani K, Spirova E, Kudryavtsev D, Shelukhina I, Tsetlin V, Romanelli MN. New quinoline derivatives as nicotinic receptor modulators. Eur J Med Chem 2016; 110:246-58. [DOI: 10.1016/j.ejmech.2016.01.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/14/2016] [Accepted: 01/15/2016] [Indexed: 11/30/2022]
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Lucero LM, Weltzin MM, Eaton JB, Cooper JF, Lindstrom JM, Lukas RJ, Whiteaker P. Differential α4(+)/(-)β2 Agonist-binding Site Contributions to α4β2 Nicotinic Acetylcholine Receptor Function within and between Isoforms. J Biol Chem 2015; 291:2444-59. [PMID: 26644472 DOI: 10.1074/jbc.m115.684373] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 11/06/2022] Open
Abstract
Two α4β2 nicotinic acetylcholine receptor (α4β2-nAChR) isoforms exist with (α4)2(β2)3 and (α4)3(β2)2 subunit stoichiometries and high versus low agonist sensitivities (HS and LS), respectively. Both isoforms contain a pair of α4(+)/(-)β2 agonist-binding sites. The LS isoform also contains a unique α4(+)/(-)α4 site with lower agonist affinity than the α4(+)/(-)β2 sites. However, the relative roles of the conserved α4(+)/(-)β2 agonist-binding sites in and between the isoforms have not been studied. We used a fully linked subunit concatemeric nAChR approach to express pure populations of HS or LS isoform α4β2*-nAChR. This approach also allowed us to mutate individual subunit interfaces, or combinations thereof, on each isoform background. We used this approach to systematically mutate a triplet of β2 subunit (-)-face E-loop residues to their non-conserved α4 subunit counterparts or vice versa (β2HQT and α4VFL, respectively). Mutant-nAChR constructs (and unmodified controls) were expressed in Xenopus oocytes. Acetylcholine concentration-response curves and maximum function were measured using two-electrode voltage clamp electrophysiology. Surface expression was measured with (125)I-mAb 295 binding and was used to define function/nAChR. If the α4(+)/(-)β2 sites contribute equally to function, making identical β2HQT substitutions at either site should produce similar functional outcomes. Instead, highly differential outcomes within the HS isoform, and between the two isoforms, were observed. In contrast, α4VFL mutation effects were very similar in all positions of both isoforms. Our results indicate that the identity of subunits neighboring the otherwise equivalent α4(+)/(-)β2 agonist sites modifies their contributions to nAChR activation and that E-loop residues are an important contributor to this neighbor effect.
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Affiliation(s)
- Linda M Lucero
- From the Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013 and
| | - Maegan M Weltzin
- From the Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013 and
| | - J Brek Eaton
- From the Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013 and
| | - John F Cooper
- the Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania 19104
| | - Jon M Lindstrom
- the Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania 19104
| | - Ronald J Lukas
- From the Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013 and
| | - Paul Whiteaker
- From the Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013 and
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Mohamed TS, Jayakar SS, Hamouda AK. Orthosteric and Allosteric Ligands of Nicotinic Acetylcholine Receptors for Smoking Cessation. Front Mol Neurosci 2015; 8:71. [PMID: 26635524 PMCID: PMC4658446 DOI: 10.3389/fnmol.2015.00071] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/06/2015] [Indexed: 12/23/2022] Open
Abstract
Nicotine addiction, the result of tobacco use, leads to over six million premature deaths world-wide per year, a number that is expected to increase by a third within the next two decades. While more than half of smokers want and attempt to quit, only a small percentage of smokers are able to quit without pharmacological interventions. Therefore, over the past decades, researchers in academia and the pharmaceutical industry have focused their attention on the development of more effective smoking cessation therapies, which is now a growing 1.9 billion dollar market. Because the role of neuronal nicotinic acetylcholine receptors (nAChR) in nicotine addiction is well established, nAChR based therapeutics remain the leading strategy for smoking cessation. However, the development of neuronal nAChR drugs that are selective for a nAChR subpopulation is challenging, and only few neuronal nAChR drugs are clinically available. Among the many neuronal nAChR subtypes that have been identified in the brain, the α4β2 subtype is the most abundant and plays a critical role in nicotine addiction. Here, we review the role of neuronal nAChRs, especially the α4β2 subtype, in the development and treatment of nicotine addiction. We also compare available smoking cessation medications and other nAChR orthosteric and allosteric ligands that have been developed with emphasis on the difficulties faced in the development of clinically useful compounds with high nAChR subtype selectivity.
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Affiliation(s)
- Tasnim S Mohamed
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center Kingsville, TX, USA
| | - Selwyn S Jayakar
- Department of Neurobiology, Harvard Medical School Boston, MA, USA
| | - Ayman K Hamouda
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center Kingsville, TX, USA ; Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Sciences Center Bryan, TX, USA
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Distinctive effects of nicotinic receptor intracellular-loop mutations associated with nocturnal frontal lobe epilepsy. Neuropharmacology 2015; 102:158-73. [PMID: 26561946 DOI: 10.1016/j.neuropharm.2015.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/02/2015] [Accepted: 11/05/2015] [Indexed: 11/21/2022]
Abstract
Previously characterized nicotinic acetylcholine receptor (nAChR) autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE)-associated mutations are found in α2, α4 and β2 subunit transmembrane (TM) domains. They predominantly increase ACh potency and, for β2-subunit mutants, increase macroscopic currents. Two recently-identified mutations, α4(R336H) and β2(V337G), located in the intracellular cytoplasmic loop (C2) have been associated with non-familial NFLE. Effects of these mutations on α4β2-nAChR function and expression were studied for the first time, using two-electrode voltage clamp recordings in Xenopus laevis oocytes. Biased-ratio preparations elucidated the mutations' effects at alternate isoforms: high-sensitivity [HS; (α4)2(β2)3] or low-sensitivity [LS; (α4)3(β2)2] via 1:10 or 30:1 [α4:β2] cRNA injection ratios, respectively. An unbiased (1:1 [α4:β2] cRNA) injection ratio was also used to study potential shifts in isoform expression. α4(R336H)-containing receptors showed significant increases in maximal ACh-induced currents (Imax) in all preparations (140% increase compared to wild type control). β2(V337G)-containing receptors significantly increased Imax in the LS-favoring preparation (20% increase compared to control). Expression of either mutation consistently produced enrichment of HS-isoform expression in all preparations. α4β2-nAChR harboring either NFLE mutant subunit showed unchanged ACh, sazetidine-A, nicotine, cytisine and mecamylamine potency. However, both mutant subunits enhanced partial agonist efficacies in the LS-biased preparation. Using β2-subunit-specific [(125)I]mAb 295 immunolabeling, nAChR cell-surface expression was determined. Antibody binding studies revealed that the β2(V337G) mutation tended to reduce cell-surface expression, and function per receptor was significantly increased by either NFLE mutant subunit in HS-favoring preparations. These findings identify both common and differing features between TM- and C2-domain AD/NFLE-associated mutations. As we discuss, the shared features may be particularly salient to AD/NFLE etiology.
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Rahman S, Engleman EA, Bell RL. Recent Advances in Nicotinic Receptor Signaling in Alcohol Abuse and Alcoholism. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 137:183-201. [PMID: 26810002 PMCID: PMC4754113 DOI: 10.1016/bs.pmbts.2015.10.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alcohol is the most commonly abused legal substance and alcoholism is a serious public health problem. It is a leading cause of preventable death in the world. The cellular and molecular mechanisms of alcohol reward and addiction are still not well understood. Emerging evidence indicates that unlike other drugs of abuse, such as nicotine, cocaine, or opioids, alcohol targets numerous channel proteins, receptor molecules, and signaling pathways in the brain. Previously, research has identified brain nicotinic acetylcholine receptors (nAChRs), a heterogeneous family of pentameric ligand-gated cation channels expressed in the mammalian brain, as critical molecular targets for alcohol abuse and dependence. Genetic variations encoding nAChR subunits have been shown to increase the vulnerability to develop alcohol dependence. Here, we review recent insights into the rewarding effects of alcohol, as they pertain to different nAChR subtypes, associated signaling molecules, and pathways that contribute to the molecular mechanisms of alcoholism and/or comorbid brain disorders. Understanding these cellular changes and molecular underpinnings may be useful for the advancement of brain nicotinic-cholinergic mechanisms, and will lead to a better translational and therapeutic outcome for alcoholism and/or comorbid conditions.
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Affiliation(s)
- Shafiqur Rahman
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, South Dakota, USA.
| | - Eric A Engleman
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Richard L Bell
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
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The role of glutamatergic, GABA-ergic, and cholinergic receptors in depression and antidepressant-like effect. Pharmacol Rep 2015; 68:443-50. [PMID: 26922551 DOI: 10.1016/j.pharep.2015.10.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 11/23/2022]
Abstract
Depression is one of the most common mental disorders and social issue worldwide. Although there are many antidepressants available, the effectiveness of the therapy is still a serious issue. Moreover, there are many limitations of currently used antidepressants, including slow onset of action, numerous side effects, or the fact that many patients do not respond adequately to the treatment. Therefore, scientists are searching for new compounds with different mechanisms of action. Numerous data indicate the important role of glutamatergic, GABA-ergic, and cholinergic receptors in the pathomechanism of major depressive disorder. This review presents the role of glutamatergic, GABA-ergic, and cholinergic receptors in depression and antidepressant-like effect.
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43
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Ogunjirin AE, Fortunak JM, Brown LL, Xiao Y, Dávila-García MI. Competition, Selectivity and Efficacy of Analogs of A-84543 for Nicotinic Acetylcholine Receptors with Repositioning of Pyridine Nitrogen. Neurochem Res 2015; 40:2131-42. [PMID: 26508288 PMCID: PMC4741274 DOI: 10.1007/s11064-015-1705-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/13/2015] [Accepted: 08/18/2015] [Indexed: 01/17/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) play a crucial role in a number of clinically relevant mental and neurological pathways, as well as autonomic and immune functions. The development of subtype-selective ligands for nAChRs therefore is potentially useful for targeted therapeutic management of conditions where nAChRs are involved. We tested if selectivity for a particular nAChR subtype can be achieved through small structural modifications of a lead compound containing the nicotinic pharmacophore by changing the distance between the electronegative elements. For this purpose, analogs of A-84543 were designed, synthesized and characterized as potentially new nAChR subtype-selective ligands. Compounds were tested for their binding properties in rat cerebral cortical tissue homogenates, and subtype-selectivity was determined using stably transfected HEK cells expressing different nAChR subtypes. All compounds synthesized were found to competitively displace [(3)H]-epibatidine ([(3)H]EB) from the nAChR binding site. Of all the analogues, H-11MNH showed highest affinity for nAChRs compared to a ~ fivefold to tenfold lower affinity of A-84543. All other compounds had affinities >10,000 nM. Both A-84543 and H-11MNH have highest affinity for α2β2 and α4β2 nAChRs and show moderate affinity for β4- and α7-containing receptors. H-11MNH was found to be a full agonist with high potency at α3β4, while A-84543 is a partial agonist with low potency. Based on their unique pharmacological binding properties we suggest that A-84543 and its desmethylpyrrolidine analog can be useful as pharmacological ligands for studying nAChRs if selective pharmacological and/or genetic tools are used to mask the function of other receptors subtypes.
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Affiliation(s)
- Adebowale E Ogunjirin
- Department of Pharmaceutical Sciences, Howard University, Washington, DC, 20059, USA
| | - Joseph M Fortunak
- Department of Pharmaceutical Sciences, Howard University, Washington, DC, 20059, USA
- Department of Chemistry, Howard University, Washington, DC, 20059, USA
| | - LaVerne L Brown
- Department of Pharmaceutical Sciences, Howard University, Washington, DC, 20059, USA
| | - Yingxian Xiao
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Martha I Dávila-García
- Department of Pharmacology, Howard University College of Medicine, Washington, DC, 20059, USA.
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Kutlu MG, Parikh V, Gould TJ. Nicotine Addiction and Psychiatric Disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 124:171-208. [PMID: 26472530 DOI: 10.1016/bs.irn.2015.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Even though smoking rates have long been on the decline, nicotine addiction still affects 20% of the US population today. Moreover, nicotine dependence shows high comorbidity with many mental illnesses including, but are not limited to, attention deficit hyperactivity disorder, anxiety disorders, and depression. The reason for the high rates of smoking in patients with mental illnesses may relate to attempts to self-medicate with nicotine. While nicotine may alleviate the symptoms of mental disorders, nicotine abstinence has been shown to worsen the symptoms of these disorders. In this chapter, we review the studies from animal and human research examining the bidirectional relationship between nicotine and attention deficit hyperactivity disorder, anxiety disorders, and depression as well as studies examining the roles of specific subunits of nicotinic acetylcholine receptors (nAChRs) in the interaction between nicotine and these mental illnesses. The results of these studies suggest that activation, desensitization, and upregulation of nAChRs modulate the effects of nicotine on mental illnesses.
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Affiliation(s)
| | - Vinay Parikh
- Temple University, Philadelphia, Pennsylvania, USA
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Bolchi C, Valoti E, Gotti C, Fasoli F, Ruggeri P, Fumagalli L, Binda M, Mucchietto V, Sciaccaluga M, Budriesi R, Fucile S, Pallavicini M. Chemistry and Pharmacology of a Series of Unichiral Analogues of 2-(2-Pyrrolidinyl)-1,4-benzodioxane, Prolinol Phenyl Ether, and Prolinol 3-Pyridyl Ether Designed as α4β2-Nicotinic Acetylcholine Receptor Agonists. J Med Chem 2015. [PMID: 26225816 DOI: 10.1021/acs.jmedchem.5b00904] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Some unichiral analogues of 2R,2'S-2-(1'-methyl-2'-pyrrolidinyl)-7-hydroxy-1,4-benzodioxane, a potent and selective α4β2-nAChR partial agonist, were designed by opening dioxane and replacing hydroxyl carbon with nitrogen. The resulting 3-pyridyl and m-hydroxyphenyl ethers have high α4β2 affinity and good subtype selectivity, which get lost if OH is removed from phenyl or the position of pyridine nitrogen is changed. High α4β2 affinity and selectivity are also attained by meta hydroxylating the 3-pyridyl and the phenyl ethers of (S)-N-methylprolinol and the phenyl ether of (S)-2-azetidinemethanol, known α4β2 agonists, although the interaction mode of the aryloxymethylene substructure cannot be assimilated to that of benzodioxane. Indeed, the α4β2 and α3β4 functional tests well differentiate behaviors that the binding tests homologize: both the 3-hydroxyphenyl and the 5-hydroxy-3-pyridyl ether of N-methylprolinol are α4β2 full agonists, but only the latter is highly α4β2/α3β4 selective, while potent and selective partial α4β2 agonism characterizes the hydroxybenzodioxane derivative and its two opened semirigid analogues.
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Affiliation(s)
- Cristiano Bolchi
- Dipartimento di Scienze Farmaceutiche "Pietro Pratesi", Università degli Studi di Milano , Via Mangiagalli 25, I-20133, Milano, Italy
| | - Ermanno Valoti
- Dipartimento di Scienze Farmaceutiche "Pietro Pratesi", Università degli Studi di Milano , Via Mangiagalli 25, I-20133, Milano, Italy
| | - Cecilia Gotti
- CNR, Istituto di Neuroscienze, and Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Via Vanvitelli 32, Milano, I-20129, Italy
| | - Francesca Fasoli
- CNR, Istituto di Neuroscienze, and Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Via Vanvitelli 32, Milano, I-20129, Italy
| | - Paola Ruggeri
- Dipartimento di Scienze Farmaceutiche "Pietro Pratesi", Università degli Studi di Milano , Via Mangiagalli 25, I-20133, Milano, Italy
| | - Laura Fumagalli
- Dipartimento di Scienze Farmaceutiche "Pietro Pratesi", Università degli Studi di Milano , Via Mangiagalli 25, I-20133, Milano, Italy
| | - Matteo Binda
- Dipartimento di Scienze Farmaceutiche "Pietro Pratesi", Università degli Studi di Milano , Via Mangiagalli 25, I-20133, Milano, Italy
| | - Vanessa Mucchietto
- CNR, Istituto di Neuroscienze, and Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Via Vanvitelli 32, Milano, I-20129, Italy
| | - Miriam Sciaccaluga
- I.R.C.C.S. Neuromed, Istituto Neurologico Mediterraneo, Via Atinese 18, I-86077, Pozzilli, Isernia, Italy
| | - Roberta Budriesi
- Dipartimento di Farmacia e Biotecnologie, Alma Mater Studiorum, Università di Bologna , Via Belmeloro 6, I-40126, Bologna, Italy
| | - Sergio Fucile
- I.R.C.C.S. Neuromed, Istituto Neurologico Mediterraneo, Via Atinese 18, I-86077, Pozzilli, Isernia, Italy.,Dipartimento di Fisiologia e Farmacologia, Università di Roma La Sapienza , Piazzale Moro 5, 00185 Roma, Italy
| | - Marco Pallavicini
- Dipartimento di Scienze Farmaceutiche "Pietro Pratesi", Università degli Studi di Milano , Via Mangiagalli 25, I-20133, Milano, Italy
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Lee AM, Wu DF, Dadgar J, Wang D, McMahon T, Messing RO. PKCε phosphorylates α4β2 nicotinic ACh receptors and promotes recovery from desensitization. Br J Pharmacol 2015; 172:4430-41. [PMID: 26103136 DOI: 10.1111/bph.13228] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 06/10/2015] [Accepted: 06/13/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Nicotinic (ACh) receptor recovery from desensitization is modulated by PKC, but the PKC isozymes and the phosphorylation sites involved have not been identified. We investigated whether PKCε phosphorylation of α4β2 nAChRs regulates receptor recovery from desensitization. EXPERIMENTAL APPROACH Receptor recovery from desensitization was investigated by electrophysiological characterization of human α4β2 nAChRs. Phosphorylation of the α4 nAChR subunit was assessed by immunoblotting of mouse synaptosomes. Hypothermia induced by sazetidine-A and nicotine was measured in Prkce(-/-) and wild-type mice. KEY RESULTS Inhibiting PKCε impaired the magnitude of α4β2 nAChR recovery from desensitization. We identified five putative PKCε phosphorylation sites in the large intracellular loop of the α4 subunit, and mutating four sites to alanines also impaired recovery from desensitization. α4 nAChR subunit phosphorylation was reduced in synaptosomes from Prkce(-/-) mice. Sazetidine-A-induced hypothermia, which is mediated by α4β2 nAChR desensitization, was more severe and prolonged in Prkce(-/-) than in wild-type mice. CONCLUSIONS AND IMPLICATIONS PKCε phosphorylates the α4 nAChR subunit and regulates recovery from receptor desensitization. This study illustrates the importance of phosphorylation in regulating α4β2 receptor function, and suggests that reducing phosphorylation prolongs receptor desensitization and decreases the number of receptors available for activation.
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Affiliation(s)
- A M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - D-F Wu
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX, USA
| | - J Dadgar
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX, USA
| | - D Wang
- Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, CA, USA
| | - T McMahon
- Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, CA, USA
| | - R O Messing
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX, USA
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Shahsavar A, Ahring PK, Olsen JA, Krintel C, Kastrup JS, Balle T, Gajhede M. Acetylcholine-Binding Protein Engineered to Mimic the α4-α4 Binding Pocket in α4β2 Nicotinic Acetylcholine Receptors Reveals Interface Specific Interactions Important for Binding and Activity. Mol Pharmacol 2015; 88:697-707. [DOI: 10.1124/mol.115.098061] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 07/15/2015] [Indexed: 12/23/2022] Open
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Pharmacologically distinct nicotinic acetylcholine receptors drive efferent-mediated excitation in calyx-bearing vestibular afferents. J Neurosci 2015; 35:3625-43. [PMID: 25716861 DOI: 10.1523/jneurosci.3388-14.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Electrical stimulation of vestibular efferent neurons rapidly excites the resting discharge of calyx/dimorphic (CD) afferents. In turtle, this excitation arises when acetylcholine (ACh), released from efferent terminals, directly depolarizes calyceal endings by activating nicotinic ACh receptors (nAChRs). Although molecular biological data from the peripheral vestibular system implicate most of the known nAChR subunits, specific information about those contributing to efferent-mediated excitation of CD afferents is lacking. We sought to identify the nAChR subunits that underlie the rapid excitation of CD afferents and whether they differ from α9α10 nAChRs on type II hair cells that drive efferent-mediated inhibition in adjacent bouton afferents. We recorded from CD and bouton afferents innervating the turtle posterior crista during electrical stimulation of vestibular efferents while applying several subtype-selective nAChR agonists and antagonists. The α9α10 nAChR antagonists, α-bungarotoxin and α-conotoxin RgIA, blocked efferent-mediated inhibition in bouton afferents while leaving efferent-mediated excitation in CD units largely intact. Conversely, 5-iodo-A-85380, sazetidine-A, varenicline, α-conotoxin MII, and bPiDDB (N,N-dodecane-1,12-diyl-bis-3-picolinium dibromide) blocked efferent-mediated excitation in CD afferents without affecting efferent-mediated inhibition in bouton afferents. This pharmacological profile suggested that calyceal nAChRs contain α6 and β2, but not α9, nAChR subunits. Selective blockade of efferent-mediated excitation in CD afferents distinguished dimorphic from calyx afferents by revealing type II hair cell input. Dimorphic afferents differed in having higher mean discharge rates and a mean efferent-mediated excitation that was smaller in amplitude yet longer in duration. Molecular biological data demonstrated the expression of α9 in turtle hair cells and α4 and β2 in associated vestibular ganglia.
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Harris AC, Tally L, Schmidt CE, Muelken P, Stepanov I, Saha S, Vogel RI, LeSage MG. Animal models to assess the abuse liability of tobacco products: effects of smokeless tobacco extracts on intracranial self-stimulation. Drug Alcohol Depend 2015; 147:60-7. [PMID: 25561387 PMCID: PMC4337227 DOI: 10.1016/j.drugalcdep.2014.12.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/12/2014] [Accepted: 12/11/2014] [Indexed: 01/11/2023]
Abstract
BACKGROUND Preclinical models are needed to inform regulation of tobacco products by the Food and Drug Administration (FDA). Typically, animal models of tobacco addiction involve exposure to nicotine alone or nicotine combined with isolated tobacco constituents (e.g. minor alkaloids). The goal of this study was to develop a model using extracts derived from tobacco products that contain a range of tobacco constituents to more closely model product exposure in humans. METHODS This study compared the addiction-related effects of nicotine alone and nicotine dose-equivalent concentrations of aqueous smokeless tobacco extracts on intracranial self-stimulation (ICSS) in rats. Extracts were prepared from Kodiak Wintergreen, a conventional product, or Camel Snus, a potential "modified risk tobacco product". Binding affinities of nicotine alone and extracts at various nicotinic acetylcholine receptor (nAChR) subtypes were also compared. RESULTS Kodiak and Camel Snus extracts contained levels of minor alkaloids within the range of those shown to enhance nicotine's behavioral effects when studied in isolation. Nonetheless, acute injection of both extracts produced reinforcement-enhancing (ICSS threshold-decreasing) effects similar to those of nicotine alone at low to moderate nicotine doses, as well as similar reinforcement-attenuating/aversive (ICSS threshold-increasing) effects at high nicotine doses. Extracts and nicotine alone also had similar binding affinity at all nAChRs studied. CONCLUSIONS Relative nicotine content is the primary pharmacological determinant of the abuse liability of Kodiak and Camel Snus as measured using ICSS. These models may be useful to compare the relative abuse liability of other tobacco products and to model FDA-mandated changes in product performance standards.
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Affiliation(s)
- Andrew C Harris
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA; Department of Psychology, University of Minnesota, Minneapolis, MN, USA.
| | - Laura Tally
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA
| | - Clare E Schmidt
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Peter Muelken
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN, USA
| | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Subhrakanti Saha
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Rachel Isaksson Vogel
- Masonic Cancer Center, Biostatistics and Bioinformatics Core, University of Minnesota Minneapolis, MN, USA
| | - Mark G LeSage
- Minneapolis Medical Research Foundation, Minneapolis, MN, USA; Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA; Department of Psychology, University of Minnesota, Minneapolis, MN, USA
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50
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Rahman S, Engleman EA, Bell RL. Nicotinic receptor modulation to treat alcohol and drug dependence. Front Neurosci 2015; 8:426. [PMID: 25642160 PMCID: PMC4295535 DOI: 10.3389/fnins.2014.00426] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 12/04/2014] [Indexed: 01/10/2023] Open
Abstract
Alcohol and drug dependence are serious public health problems worldwide. The prevalence of alcohol and drug dependence in the United States and other parts of the world is significant. Given the limitations in the efficacy of current pharmacotherapies to treat these disorders, research in developing alternative pharmacotherapies continues. Preclinical and clinical evidence thus far has indicated that brain nicotinic acetylcholine receptors (nAChRs) are important pharmacological targets for the development of medications to treat alcohol and drug dependence. The nAChRs are a super family of ligand gated ion channels, and are expressed throughout the brain with twelve neuronal nAChR subunits (α2–α10 and β2–β4) identified. Here, we review preclinical and clinical evidence involving a number of nAChR ligands that target different nAChR subtypes in alcohol and nicotine addiction. The important ligands include cytisine, lobeline, mecamylamine, varenicline, sazetidine A and others that target α4β2* nAChR subtypes as small molecule modulators of the brain nicotinic cholinergic system are also discussed. Taken together, both preclinical and clinical data exist that support nAChR–based ligands as promising therapeutic agents for the treatment of alcohol and drug dependence.
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Affiliation(s)
- Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University Brookings, SD, USA
| | - Eric A Engleman
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine Indianapolis, IN, USA
| | - Richard L Bell
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine Indianapolis, IN, USA
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