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Hamouda AK, Bautista MR, Akinola LS, Alkhlaif Y, Jackson A, Carper M, Toma WB, Garai S, Chen YC, Thakur GA, Fowler CD, Damaj MI. Potentiation of (α4)2(β2)3, but not (α4)3(β2)2, nicotinic acetylcholine receptors reduces nicotine self-administration and withdrawal symptoms. Neuropharmacology 2021; 190:108568. [PMID: 33878302 DOI: 10.1016/j.neuropharm.2021.108568] [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: 12/21/2020] [Revised: 02/28/2021] [Accepted: 04/10/2021] [Indexed: 11/26/2022]
Abstract
The low sensitivity (α4)3(β2)2 (LS) and high sensitivity (α4)2(β2)3 (HS) nAChR isoforms may contribute to a variety of brain functions, pathophysiological processes, and pharmacological effects associated with nicotine use. In this study, we examined the contributions of the LS and HS α4β2 nAChR isoforms in nicotine self-administration, withdrawal symptoms, antinociceptive and hypothermic effects. We utilized two nAChR positive allosteric modulators (PAMs): desformylflustrabromine (dFBr), a PAM of both the LS and HS α4β2 nAChRs, and CMPI, a PAM selective for the LS nAChR. We found that dFBr, but not CMPI, decreased intravenous nicotine self-administration in male mice in a dose-dependent manner. Unlike dFBr, which fully reverses somatic and affective symptoms of nicotine withdrawal, CMPI at doses up to 15 mg/kg in male mice only partially reduced nicotine withdrawal-induced somatic signs, anxiety-like behavior and sucrose preference, but had no effects on nicotine withdrawal-induced hyperalgesia. These results indicate that potentiation of HS α4β2 nAChRs is necessary to modulate nicotine's reinforcing properties that underlie nicotine intake and to reverse nicotine withdrawal symptoms that influence nicotine abstinence. In contrast, both dFBr and CMPI enhanced nicotine's hypothermic effect and reduced nicotine's antinociceptive effects in male mice. Therefore, these results indicate a more prevalent role of HS α4β2 nAChR isoforms in mediating various behavioral effects associated with nicotine, whereas the LS α4β2 nAChR isoform has a limited role in mediating body temperature and nociceptive responses. These findings will facilitate the development of more selective, efficacious, and safe nAChR-based therapeutics for nicotine addiction treatment.
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Affiliation(s)
- Ayman K Hamouda
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Texas at Tyler, Tyler, TX, USA.
| | - Malia R Bautista
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA
| | - Lois S Akinola
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Yasmin Alkhlaif
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Asti Jackson
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Moriah Carper
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Wisam B Toma
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Yen-Chu Chen
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Christie D Fowler
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA.
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2
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Shi Z, Qin M, Huang L, Xu T, Chen Y, Hu Q, Peng S, Peng Z, Qu LN, Chen SG, Tuo QH, Liao DF, Wang XP, Wu RR, Yuan TF, Li YH, Liu XM. Human torpor: translating insights from nature into manned deep space expedition. Biol Rev Camb Philos Soc 2020; 96:642-672. [PMID: 33314677 DOI: 10.1111/brv.12671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/09/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022]
Abstract
During a long-duration manned spaceflight mission, such as flying to Mars and beyond, all crew members will spend a long period in an independent spacecraft with closed-loop bioregenerative life-support systems. Saving resources and reducing medical risks, particularly in mental heath, are key technology gaps hampering human expedition into deep space. In the 1960s, several scientists proposed that an induced state of suppressed metabolism in humans, which mimics 'hibernation', could be an ideal solution to cope with many issues during spaceflight. In recent years, with the introduction of specific methods, it is becoming more feasible to induce an artificial hibernation-like state (synthetic torpor) in non-hibernating species. Natural torpor is a fascinating, yet enigmatic, physiological process in which metabolic rate (MR), body core temperature (Tb ) and behavioural activity are reduced to save energy during harsh seasonal conditions. It employs a complex central neural network to orchestrate a homeostatic state of hypometabolism, hypothermia and hypoactivity in response to environmental challenges. The anatomical and functional connections within the central nervous system (CNS) lie at the heart of controlling synthetic torpor. Although progress has been made, the precise mechanisms underlying the active regulation of the torpor-arousal transition, and their profound influence on neural function and behaviour, which are critical concerns for safe and reversible human torpor, remain poorly understood. In this review, we place particular emphasis on elaborating the central nervous mechanism orchestrating the torpor-arousal transition in both non-flying hibernating mammals and non-hibernating species, and aim to provide translational insights into long-duration manned spaceflight. In addition, identifying difficulties and challenges ahead will underscore important concerns in engineering synthetic torpor in humans. We believe that synthetic torpor may not be the only option for manned long-duration spaceflight, but it is the most achievable solution in the foreseeable future. Translating the available knowledge from natural torpor research will not only benefit manned spaceflight, but also many clinical settings attempting to manipulate energy metabolism and neurobehavioural functions.
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Affiliation(s)
- Zhe Shi
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China.,Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China
| | - Meng Qin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Lu Huang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China
| | - Tao Xu
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Ying Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Qin Hu
- College of Life Sciences and Bio-Engineering, Beijing University of Technology, Beijing, 100024, China
| | - Sha Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Zhuang Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Li-Na Qu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Shan-Guang Chen
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Qin-Hui Tuo
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Duan-Fang Liao
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Xiao-Ping Wang
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ren-Rong Wu
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, China
| | - Ying-Hui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xin-Min Liu
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development (IMPLAD), Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193, China
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3
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Moerke MJ, McMahon LR, Wilkerson JL. More than Smoke and Patches: The Quest for Pharmacotherapies to Treat Tobacco Use Disorder. Pharmacol Rev 2020; 72:527-557. [PMID: 32205338 DOI: 10.1124/pr.119.018028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tobacco use is a persistent public health issue. It kills up to half its users and is the cause of nearly 90% of all lung cancers. The main psychoactive component of tobacco is nicotine, primarily responsible for its abuse-related effects. Accordingly, most pharmacotherapies for smoking cessation target nicotinic acetylcholine receptors (nAChRs), nicotine's major site of action in the brain. The goal of the current review is twofold: first, to provide a brief overview of the most commonly used behavioral procedures for evaluating smoking cessation pharmacotherapies and an introduction to pharmacokinetic and pharmacodynamic properties of nicotine important for consideration in the development of new pharmacotherapies; and second, to discuss current and potential future pharmacological interventions aimed at decreasing tobacco use. Attention will focus on the potential for allosteric modulators of nAChRs to offer an improvement over currently approved pharmacotherapies. Additionally, given increasing public concern for the potential health consequences of using electronic nicotine delivery systems, which allow users to inhale aerosolized solutions as an alternative to smoking tobacco, an effort will be made throughout this review to address the implications of this relatively new form of nicotine delivery, specifically as it relates to smoking cessation. SIGNIFICANCE STATEMENT: Despite decades of research that have vastly improved our understanding of nicotine and its effects on the body, only a handful of pharmacotherapies have been successfully developed for use in smoking cessation. Thus, investigation of alternative pharmacological strategies for treating tobacco use disorder remains active; allosteric modulators of nicotinic acetylcholine receptors represent one class of compounds currently under development for this purpose.
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Affiliation(s)
- M J Moerke
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
| | - L R McMahon
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
| | - J L Wilkerson
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
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4
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Deba F, Ramos K, Vannoy M, Munoz K, Akinola LS, Damaj MI, Hamouda AK. Examining the Effects of (α4)3(β2)2 Nicotinic Acetylcholine Receptor-Selective Positive Allosteric Modulator on Acute Thermal Nociception in Rats. Molecules 2020; 25:molecules25122923. [PMID: 32630476 PMCID: PMC7355939 DOI: 10.3390/molecules25122923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022] Open
Abstract
Neuronal nicotinic acetylcholine receptor (nAChR)-based therapeutics are sought as a potential alternative strategy to opioids for pain management. In this study, we examine the antinociceptive effects of 3-(2-chlorophenyl)-5-(5-methyl-1-(piperidin-4-yl)-1H-pyrazol-4-yl)isoxazole (CMPI), a novel positive allosteric modulator (PAM), with preferential selectivity to the low agonist sensitivity (α4)3(β2)2 nAChR and desformylflustrabromine (dFBr), a PAM for α4-containing nAChRs. We used hot plate and tail flick tests to measure the effect of dFBr and CMPI on the latency to acute thermal nociceptive responses in rats. Intraperitoneal injection of dFBr, but not CMPI, dose-dependently increased latency in the hot plate test. In the tail flick test, the effect achieved at the highest dFBr or CMPI dose tested was only <20% of the maximum possible effects reported for nicotine and other nicotinic agonists. Moreover, the coadministration of dFBr did not enhance the antinociceptive effect of a low dose of nicotine. Our results show that the direct acute effect of dFBr is superior to that for CMPI, indicating that selectivity to (α4)3(β2)2 nAChR is not advantageous in alleviating responses to acute thermal nociceptive stimulus. However, further studies are necessary to test the suitability of (α4)3(β2)2 nAChR-selective PAMs in chronic pain models.
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Affiliation(s)
- Farah Deba
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Texas at Tyler, Tyler, TX 75799, USA;
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center MS 131, 1010 W. Ave. B, Kingsville, TX 78363, USA; (K.R.); (M.V.); (K.M.)
| | - Kara Ramos
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center MS 131, 1010 W. Ave. B, Kingsville, TX 78363, USA; (K.R.); (M.V.); (K.M.)
| | - Matthew Vannoy
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center MS 131, 1010 W. Ave. B, Kingsville, TX 78363, USA; (K.R.); (M.V.); (K.M.)
| | - Kemburli Munoz
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center MS 131, 1010 W. Ave. B, Kingsville, TX 78363, USA; (K.R.); (M.V.); (K.M.)
| | - Lois S. Akinola
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Kontos Medical Science Building, 1217 E. Marshall St., P.O. Box 980613, Richmond, VA 23298, USA; (L.S.A.); (M.I.D.)
| | - M. Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Kontos Medical Science Building, 1217 E. Marshall St., P.O. Box 980613, Richmond, VA 23298, USA; (L.S.A.); (M.I.D.)
| | - Ayman K. Hamouda
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Texas at Tyler, Tyler, TX 75799, USA;
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center MS 131, 1010 W. Ave. B, Kingsville, TX 78363, USA; (K.R.); (M.V.); (K.M.)
- Correspondence: ; Tel.: +1-903-565-6578
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5
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Wilkerson JL, Deba F, Crowley ML, Hamouda AK, McMahon LR. Advances in the In vitro and In vivo pharmacology of Alpha4beta2 nicotinic receptor positive allosteric modulators. Neuropharmacology 2020; 168:108008. [PMID: 32113032 DOI: 10.1016/j.neuropharm.2020.108008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/08/2020] [Accepted: 02/11/2020] [Indexed: 11/29/2022]
Abstract
Receptors containing α4 and β2 subunits are a major neuronal nicotinic acetylcholine receptor (nAChR) subtype in the brain. This receptor plays a critical role in nicotine addiction, with potential smoking cessation therapeutics producing modulation of α4β2 nAChR. In addition, compounds that act as agonists at α4β2 nAChR may be useful for the treatment of pathological pain. Further, as the α4β2 nAChR has been implicated in cognition, therapeutics that act as α4β2 nAChR agonists are also being examined as treatments for cognitive disorders and neurological diseases that impact cognitive function, such as Alzheimer's disease and schizophrenia. This review will cover the molecular in vitro evidence that allosteric modulators of the α4β2 neuronal nAChR provide several advantages over traditional α4β2 nAChR orthosteric ligands. Specifically, we explore the concept that nAChR allosteric modulators allow for greater pharmacological selectivity, while minimizing potential deleterious off-target effects. Further, here we discuss the development and preclinical in vivo behavioral assessment of allosteric modulators at the α4β2 neuronal nAChR as therapeutics for smoking cessation, pathological pain, as well as cognitive disorders and neurological diseases that impact cognitive function. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Jenny L Wilkerson
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States.
| | - Farah Deba
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Texas at Tyler, Tyler, TX, 75799, United States
| | - Morgan L Crowley
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States
| | - Ayman K Hamouda
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Texas at Tyler, Tyler, TX, 75799, United States.
| | - Lance R McMahon
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States.
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6
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Hamouda AK, Jackson A, Bagdas D, Imad Damaj M. Reversal of Nicotine Withdrawal Signs Through Positive Allosteric Modulation of α4β2 Nicotinic Acetylcholine Receptors in Male Mice. Nicotine Tob Res 2019; 20:903-907. [PMID: 29059422 DOI: 10.1093/ntr/ntx183] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/15/2017] [Indexed: 01/03/2023]
Abstract
Introduction Nicotine withdrawal symptoms are important factors in determining the relapse rate to tobacco smoking and drugs that diminish these symptoms would potentially have a higher success rate as smoking cessation aids. Unlike US Food and Drug administration approved smoke cessation aids (nicotine and varenicline) which act as nicotinic acetylcholine receptors (nAChRs) agonists, desformylflustrabromine (dFBr) acts as a nAChR positive allosteric modulator with higher selectivity to the α4β2 nAChR. In animal studies, dFBr was well tolerated and reduced intravenous nicotine self-administration. In this study, we use behavioral test in mouse model of spontaneous nicotine withdrawal to assess the effect of dFBr on nicotine withdrawal symptoms. Methods Spontaneous nicotine withdrawal in nicotine-dependent ICR male mice was established 18-24 h after termination (minipump removal) of 14 days infusion of nicotine. After that (day 15), spontaneous signs of nicotine withdrawal were examined in the following order: anxiety-like behaviors, somatic signs, and then hyperalgesia using previously published behavioral protocols. Fifteen minutes before withdrawal signs testing, mice received a subcutaneous acute injection of vehicle or dFBr at the doses of 0.02, 0.1, and 1 mg/kg to determine the effect of dFBr on nicotine withdrawal symptoms. Results dFBr produced dose-dependent reversal of nicotine withdrawal signs in mouse model of spontaneous nicotine withdrawal. Implications Positive allosteric modulators of nAChR such as dFBr reduce nicotine withdrawal symptoms supporting the potential clinical use of this novel class of nAChR-based therapeutics as smoking cessation aid.
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Affiliation(s)
- Ayman K Hamouda
- Department of Pharmaceutical Sciences, College of Pharmacy, Texas A&M Health Sciences Center MS, Kingsville, TX
| | - Asti Jackson
- Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA
| | - Deniz Bagdas
- Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA.,Experimental Animals Breeding and Research Center, Faculty of Medicine, Uludag University, Bursa, Turkey
| | - M Imad Damaj
- Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA
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7
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Moerke MJ, McMahon LR. Nicotine-like discriminative stimulus effects of acetylcholinesterase inhibitors and a muscarinic receptor agonist in Rhesus monkeys. Drug Dev Ind Pharm 2019; 45:861-867. [PMID: 30712397 DOI: 10.1080/03639045.2019.1578787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Acetylcholinesterase (AChE) inhibitors and positive allosteric nicotinic acetylcholine receptor (nAChR) modulators are potential pharmacotherapies for nicotine dependence. Because some smoking cessation aids (e.g. varenicline) appear to work by mimicking the effects of nicotine, we used drug discrimination to examine whether AChE inhibitors and nAChR allosteric modulators mimic the effects of nicotine. Rhesus monkeys discriminated 1.78 mg/kg of nicotine s.c. under an FR5 schedule of stimulus-shock termination. Nicotine and the AChE inhibitors donepezil and galantamine dose-dependently increased responding on the nicotine-appropriate lever with ED50 values of 0.35, 0.22, and 0.77 mg/kg, respectively. Donepezil (0.56 mg/kg) produced nicotine-like effects for at least 6 h, whereas the duration of action of galantamine (1.78 mg/kg) was less than 3 h. The positive allosteric nAChR modulator PNU-120596 (up to 10 mg/kg) and midazolam (up to 1.0 mg/kg) produced no more than 22% nicotine-lever responding. Oxotremorine, a muscarinic acetylcholine receptor agonist that was used to explore the extent to which muscarinic receptor agonism might contribute to the effects of AChE inhibitors, produced 94% nicotine-lever responding (ED50 value 0.013 mg/kg). The muscarinic antagonist atropine significantly antagonized the effects of both oxotremorine and nicotine; however, the dose of atropine antagonizing oxotremorine was smaller than the dose required to antagonize nicotine. Collectively, these results suggest that AChE inhibitors can mimic the effects of nicotine by indirectly stimulating both nicotinic and muscarinic receptors. Inasmuch as some smoking cessation aids work by exerting nicotine-like effects, the current results are consistent with the potential use of AChE inhibitors as novel smoking cessation aids.
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Affiliation(s)
- Megan J Moerke
- a Department of Pharmacodynamics , College of Pharmacy, University of Florida , Gainesville , FL , USA
| | - Lance R McMahon
- a Department of Pharmacodynamics , College of Pharmacy, University of Florida , Gainesville , FL , USA
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8
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A pharmacological composition for induction of a reversible torpor-like state and hypothermia in rats. Life Sci 2019; 219:190-198. [DOI: 10.1016/j.lfs.2019.01.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 12/15/2022]
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9
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Differential cross-tolerance to the effects of nicotinic acetylcholine receptor drugs in C57BL/6J mice following chronic varenicline. Behav Pharmacol 2018; 30:412-421. [PMID: 30398980 DOI: 10.1097/fbp.0000000000000452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Varenicline is a smoking cessation pharmacotherapy with a presumed mechanism of action of partial efficacy at the α4β2 nicotinic acetylcholine receptor (nAChR); however, the extent to which daily varenicline use leads to changes in nAChR sensitivity is unclear. This study examined the consequences of daily varenicline treatment on disruptions in operant responding (i.e. rate-decreasing effects) and hypothermia induced by administration of nicotine, epibatidine, cytisine, and cocaine in C57BL/6J mice. Furthermore, mecamylamine was used to assess the involvement of nAChRs in the effects of varenicline. Mice were trained under a fixed ratio 20 of milk reinforcement, and rectal temperatures were measured after 30 min following drug-administration. Varenicline, nicotine, epibatidine, and cytisine produced dose-dependent decreases in response rate and rectal temperature. Chronic varenicline (30 mg/kg) engendered tolerance to varenicline, but more cross-tolerance to nicotine, for both disruptions in operant responding and hypothermia. Cross-tolerance only developed to the hypothermic effects of epibatidine, and no cross-tolerance developed to any effects of cytisine and cocaine. In varenicline-tolerant mice, mecamylamine did not antagonize the effects of varenicline. The varying magnitudes of tolerance and cross-tolerance among effects and drugs are indicative of a nonuniform nAChR pharmacology in vivo.
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10
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Hernandez J, Volland A, Leyshon BJ, Juda M, Ridlon JM, Johnson RW, Steelman AJ. Effect of imidacloprid ingestion on immune responses to porcine reproductive and respiratory syndrome virus. Sci Rep 2018; 8:11615. [PMID: 30072754 PMCID: PMC6072715 DOI: 10.1038/s41598-018-30093-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 07/23/2018] [Indexed: 12/19/2022] Open
Abstract
Nicotine and acetylcholine cause immunosuppresion by signaling to the α7 nicotinic acetylcholine receptor (α7 nAChR) on immune cells. Neonicotinoids are nAChR agonists and widly used insecticides. We aimed to define the immunosuppressive potential of dietary exposure to the neonicotinoid imidacloprid (IMI) on the generation of innate and adaptive immune responses to porcine reproductive and respiratory syndrome virus (PRRSV). Piglets were randomized into groups based on diet and infection. Behavioral signs of illness were recorded. Urine IMI levels were measured by high performance liquid chromatography-mass spectrometry. Flow cytometry was used to determine the expression pattern of the α7 nAChR on porcine leukocytes as well as the effects of infection and treatment on circulating leukocyte populations. Serum cytokines and PRRSV-specific antibody levels were determined by ELISA. Viral RNA in lung, spleen and plasma was determined by RT-qPCR. Pigs in the treatment group had elevated urine levels of IMI. Treatment with IMI reduced body weight, caused bouts of hypothermia, increased serum IL-10 and elevated levels of virus-specific antibodies. Viral RNA levels in the spleen showed a trend toward being increased in pigs fed IMI. Our data indicates that IMI injection may modulate virus specific immune function during PRRSV infection.
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Affiliation(s)
- J Hernandez
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.,Integrative Immunology and Behavior Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - A Volland
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - B J Leyshon
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - M Juda
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - J M Ridlon
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.,Carl R. Woese Institute for Genome Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - R W Johnson
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.,Integrative Immunology and Behavior Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.,Department of Neuroscience, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - A J Steelman
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA. .,Integrative Immunology and Behavior Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA. .,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA. .,Department of Neuroscience, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
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Bagdas D, Ergun D, Jackson A, Toma W, Schulte M, Damaj M. Allosteric modulation of α4β2* nicotinic acetylcholine receptors: Desformylflustrabromine potentiates antiallodynic response of nicotine in a mouse model of neuropathic pain. Eur J Pain 2018; 22:84-93. [PMID: 28809075 PMCID: PMC9829446 DOI: 10.1002/ejp.1092] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2017] [Indexed: 01/12/2023]
Abstract
BACKGROUND Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels. The α4β2 subtype of nAChRs plays an important role in the mediation of pain and several nicotine-evoked responses. Agonists and partial agonists of α4β2 nAChRs show efficacy in animal pain models. In addition, the antinociceptive properties of nicotine, a non-selective nAChR agonist with a high affinity for α4β2 nAChRs, is well-known. There is a growing body of evidence pointing to allosteric modulation of nAChRs as an alternative treatment strategy in experimental pain. Desformylflustrabromine (dFBr) is a positive allosteric modulator (PAM) at α4β2 nAChRs that enhances agonist responses without activating receptors. We hypothesized that dFBr may enhance nicotine-induced antinociception. METHODS The present study investigated whether dFBr could attenuate mouse chronic constriction injury (CCI)-induced neuropathic pain by increasing endogenous cholinergic tone or potentiating the nicotine-evoked antiallodynic response. RESULTS We found that subcutaneous administration of dFBr failed to reduce pain behaviour on its own. However, the combination of dFBr with nicotine significantly reversed neuropathic pain behaviour dose- and time-dependently without motor impairment. Our data revealed that this effect was mediated by the α4β2 nAChRs by using competitive α4β2 antagonist dihydro-β-erythroidine. In addition, dFBr failed to potentiate the antiallodynic effect of morphine, which shows the effect of dFBr is unique to α4β2 nAChRs. CONCLUSIONS The present results suggest that allosteric modulation of α4β2 nAChR may provide new strategies in chronic neuropathic pain. SIGNIFICANCE α4β2 nAChRs are involved in pain modulation. dFBr, a PAM at α4β2 nAChRs, potentiates the nicotine response dose-dependently in neuropathic pain. Thus, the present results suggest that allosteric modulation of α4β2* nAChR may provide new strategies in chronic neuropathic pain.
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Affiliation(s)
- D. Bagdas
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0613 USA,Experimental Animals Breeding and Research Center, Faculty of Medicine, Uludag University, Bursa 16059, Turkey
| | - D. Ergun
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0613 USA
| | - A. Jackson
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0613 USA
| | - W. Toma
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0613 USA
| | - M.K. Schulte
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, USA
| | - M.I. Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0613 USA
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de Moura FB, McMahon LR. The contribution of α4β2 and non-α4β2 nicotinic acetylcholine receptors to the discriminative stimulus effects of nicotine and varenicline in mice. Psychopharmacology (Berl) 2017; 234:781-792. [PMID: 28028600 PMCID: PMC5309148 DOI: 10.1007/s00213-016-4514-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 12/16/2016] [Indexed: 10/20/2022]
Abstract
RATIONALE The extent to which non-α4β2 versus α4β2* nAChRs contribute to the behavioral effects of varenicline and other nAChR agonists is unclear. OBJECTIVES The purpose of this study was to characterize the discriminative stimulus effects of varenicline and nicotine using various nAChR agonists and antagonists to elucidate possible non-α4β2 nAChR mechanisms. METHODS Separate groups of male C57BL/6J mice were trained to discriminate varenicline (3.2 mg/kg) or nicotine (1 mg/kg). Test drugs included mecamylamine; the nAChR agonists epibatidine, nicotine, cytisine, varenicline, and RTI-102; the β2-containing nAChR antagonist dihydro-β-erythroidine (DHβE); the α7 nAChR agonist PNU-282987; the α7 antagonist methyllycaconitine (MLA); the α3β4 antagonist 18-methoxycoronaridine (18-MC); and the non-nAChR drugs midazolam and cocaine. RESULTS In nicotine-trained mice, maximum nicotine-appropriate responding was 95% nicotine, 94% epibatidine, 63% varenicline, 58% cytisine, and less than 50% for RTI-102, PNU-282987, midazolam, and cocaine. In varenicline-trained mice, maximum varenicline-appropriate responding was 90% varenicline, 86% epibatidine, 74% cytisine, 80% RTI-102, 50% cocaine, and 50% or less for nicotine, PNU-282987, and midazolam. Drugs were studied to doses that abolished operant responding. Mecamylamine antagonized the discriminative stimulus effects, but not the rate-decreasing effects, of nicotine and varenicline. DHβE antagonized the discriminative stimulus and rate-decreasing effects of nicotine but not varenicline in either the nicotine or varenicline discrimination assays. The discriminative stimulus, but not the rate-decreasing, effects of epibatidine were antagonized by DHβE regardless of the training drug. CONCLUSIONS These results suggest that α4β2* nAChRs differentially mediate the discriminative stimulus effects of nicotine and varenicline, and suggest that varenicline has substantial non-α4β2 nAChR activity.
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Affiliation(s)
- Fernando B de Moura
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA
| | - Lance R McMahon
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA.
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