1
|
Tsuzuki A, Yamasaki M, Konno K, Miyazaki T, Takei N, Tomita S, Yuzaki M, Watanabe M. Abundant extrasynaptic expression of α3β4-containing nicotinic acetylcholine receptors in the medial habenula-interpeduncular nucleus pathway in mice. Sci Rep 2024; 14:14193. [PMID: 38902419 PMCID: PMC11189931 DOI: 10.1038/s41598-024-65076-3] [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: 03/15/2024] [Accepted: 06/17/2024] [Indexed: 06/22/2024] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) in the medial habenula (MHb)-interpeduncular nucleus (IPN) pathway play critical roles in nicotine-related behaviors. This pathway is particularly enriched in nAChR α3 and β4 subunits, both of which are genetically linked to nicotine dependence. However, the cellular and subcellular expression of endogenous α3β4-containing nAChRs remains largely unknown because specific antibodies and appropriate detection methods were unavailable. Here, we successfully uncovered the expression of endogenous nAChRs containing α3 and β4 subunits in the MHb-IPN pathway using novel specific antibodies and a fixative glyoxal that enables simultaneous detection of synaptic and extrasynaptic molecules. Immunofluorescence and immunoelectron microscopy revealed that both subunits were predominantly localized to the extrasynaptic cell surface of somatodendritic and axonal compartments of MHb neurons but not at their synaptic junctions. Immunolabeling for α3 and β4 subunits disappeared in α5β4-knockout brains, which we used as negative controls. The enriched and diffuse extrasynaptic expression along the MHb-IPN pathway suggests that α3β4-containing nAChRs may enhance the excitability of MHb neurons and neurotransmitter release from their presynaptic terminals in the IPN. The revealed distribution pattern provides a molecular and anatomical basis for understanding the functional role of α3β4-containing nAChRs in the crucial pathway of nicotine dependence.
Collapse
Grants
- 17KK0160 Ministry of Education, Culture, Sports, Science and Technology
- 21K06746 Ministry of Education, Culture, Sports, Science and Technology
- 22K06784 Ministry of Education, Culture, Sports, Science and Technology
- 20H05628 Ministry of Education, Culture, Sports, Science and Technology
- 20H05628 Ministry of Education, Culture, Sports, Science and Technology
Collapse
Affiliation(s)
- Asuka Tsuzuki
- Department of Anatomy, Graduate School of Medicine, Hokkaido University, Sapporo, 060-8638, Japan
| | - Miwako Yamasaki
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, 060-8638, Japan.
| | - Kohtarou Konno
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, 060-8638, Japan
| | - Taisuke Miyazaki
- Department of Functioning and Disability, Faculty of Health Sciences, Hokkaido University, Sapporo, 060-8638, Japan
| | - Norio Takei
- Institute for Animal Experimentation, Faculty of Medicine, Hokkaido University, Sapporo, 060-8638, Japan
| | - Susumu Tomita
- Department of Cellular and Molecular Physiology, Department of Neuroscience, and Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Michisuke Yuzaki
- Department of Physiology, School of Medicine, Keio University, Tokyo, 160-8582, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, 060-8638, Japan
| |
Collapse
|
2
|
York JM, Borghese CM, George AA, Cannatella DC, Zakon HH. A potential cost of evolving epibatidine resistance in poison frogs. BMC Biol 2023; 21:144. [PMID: 37370119 DOI: 10.1186/s12915-023-01637-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 05/30/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND Some dendrobatid poison frogs sequester the toxin epibatidine as a defense against predators. We previously identified an amino acid substitution (S108C) at a highly conserved site in a nicotinic acetylcholine receptor β2 subunit of dendrobatid frogs that decreases sensitivity to epibatidine in the brain-expressing α4β2 receptor. Introduction of S108C to the orthologous high-sensitivity human receptor similarly decreased sensitivity to epibatidine but also decreased sensitivity to acetylcholine, a potential cost if this were to occur in dendrobatids. This decrease in the acetylcholine sensitivity manifested as a biphasic acetylcholine concentration-response curve consistent with the addition of low-sensitivity receptors. Surprisingly, the addition of the β2 S108C into the α4β2 receptor of the dendrobatid Epipedobates anthonyi did not change acetylcholine sensitivity, appearing cost-free. We proposed that toxin-bearing dendrobatids may have additional amino acid substitutions protecting their receptors from alterations in acetylcholine sensitivity. To test this, in the current study, we compared the dendrobatid receptor to its homologs from two non-dendrobatid frogs. RESULTS The introduction of S108C into the α4β2 receptors of two non-dendrobatid frogs also does not affect acetylcholine sensitivity suggesting no additional dendrobatid-specific substitutions. However, S108C decreased the magnitude of neurotransmitter-induced currents in Epipedobates and the non-dendrobatid frogs. We confirmed that decreased current resulted from fewer receptors in the plasma membrane in Epipedobates using radiolabeled antibodies against the receptors. To test whether S108C alteration of acetylcholine sensitivity in the human receptor was due to (1) adding low-sensitivity binding sites by changing stoichiometry or (2) converting existing high- to low-sensitivity binding sites with no stoichiometric alteration, we made concatenated α4β2 receptors in stoichiometry with only high-sensitivity sites. S108C substitutions decreased maximal current and number of immunolabeled receptors but no longer altered acetylcholine sensitivity. CONCLUSIONS The most parsimonious explanation of our current and previous work is that the S108C substitution renders the β2 subunit less efficient in assembling/trafficking, thereby decreasing the number of receptors in the plasma membrane. Thus, while β2 S108C protects dendrobatids against sequestered epibatidine, it incurs a potential physiological cost of disrupted α4β2 receptor function.
Collapse
Affiliation(s)
- Julia M York
- Department of Neuroscience, The University of Texas, Austin, TX, USA
- Department of Integrative Biology, and Biodiversity Center, The University of Texas, Austin, TX, USA
| | | | - Andrew A George
- Department of Neurobiology, The Barrow Neurological Institute, Phoenix, AZ, USA
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - David C Cannatella
- Department of Integrative Biology, and Biodiversity Center, The University of Texas, Austin, TX, USA
| | - Harold H Zakon
- Department of Neuroscience, The University of Texas, Austin, TX, USA.
- Department of Integrative Biology, and Biodiversity Center, The University of Texas, Austin, TX, USA.
| |
Collapse
|
3
|
Becchetti A, Grandi LC, Cerina M, Amadeo A. Nicotinic acetylcholine receptors and epilepsy. Pharmacol Res 2023; 189:106698. [PMID: 36796465 DOI: 10.1016/j.phrs.2023.106698] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/04/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023]
Abstract
Despite recent advances in understanding the causes of epilepsy, especially the genetic, comprehending the biological mechanisms that lead to the epileptic phenotype remains difficult. A paradigmatic case is constituted by the epilepsies caused by altered neuronal nicotinic acetylcholine receptors (nAChRs), which exert complex physiological functions in mature as well as developing brain. The ascending cholinergic projections exert potent control of forebrain excitability, and wide evidence implicates nAChR dysregulation as both cause and effect of epileptiform activity. First, tonic-clonic seizures are triggered by administration of high doses of nicotinic agonists, whereas non-convulsive doses have kindling effects. Second, sleep-related epilepsy can be caused by mutations on genes encoding nAChR subunits widely expressed in the forebrain (CHRNA4, CHRNB2, CHRNA2). Third, in animal models of acquired epilepsy, complex time-dependent alterations in cholinergic innervation are observed following repeated seizures. Heteromeric nAChRs are central players in epileptogenesis. Evidence is wide for autosomal dominant sleep-related hypermotor epilepsy (ADSHE). Studies of ADSHE-linked nAChR subunits in expression systems suggest that the epileptogenic process is promoted by overactive receptors. Investigation in animal models of ADSHE indicates that expression of mutant nAChRs can lead to lifelong hyperexcitability by altering i) the function of GABAergic populations in the mature neocortex and thalamus, ii) synaptic architecture during synaptogenesis. Understanding the balance of the epileptogenic effects in adult and developing networks is essential to plan rational therapy at different ages. Combining this knowledge with a deeper understanding of the functional and pharmacological properties of individual mutations will advance precision and personalized medicine in nAChR-dependent epilepsy.
Collapse
Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy.
| | - Laura Clara Grandi
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy.
| | - Marta Cerina
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy.
| | - Alida Amadeo
- Department of Biosciences, University of Milano, Via Celoria 26, Milano 20133, Italy.
| |
Collapse
|
4
|
York JM, Borghese CM, George AA, Cannatella DC, Zakon HH. A potential cost of evolving epibatidine resistance in poison frogs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.04.522789. [PMID: 36711899 PMCID: PMC9882002 DOI: 10.1101/2023.01.04.522789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background Some poison arrow frogs sequester the toxin epibatidine as a defense against predators. We previously identified a single amino acid substitution (S108C) at a highly conserved site in a neuronal nicotinic acetylcholine receptor (nAChR) ß2 subunit that prevents epibatidine from binding to this receptor. When placed in a homologous mammalian nAChR this substitution minimized epibatidine binding but also perturbed acetylcholine binding, a clear cost. However, in the nAChRs of poison arrow frogs, this substitution appeared to have no detrimental effect on acetylcholine binding and, thus, appeared cost-free. Results The introduction of S108C into the α4β2 nAChRs of non-dendrobatid frogs also does not affect ACh sensitivity, when these receptors are expressed in Xenopus laevis oocytes. However, α4β2 nAChRs with C108 had a decreased magnitude of neurotransmitter-induced currents in all species tested ( Epipedobates anthonyi , non-dendrobatid frogs, as well as human), compared with α4β2 nAChRs with the conserved S108. Immunolabeling of frog or human α4β2 nAChRs in the plasma membrane using radiolabeled antibody against the β2 nAChR subunit shows that C108 significantly decreased the number of cell-surface α4β2 nAChRs, compared with S108. Conclusions While S108C protects these species against sequestered epibatidine, it incurs a potential physiological cost of disrupted α4β2 nAChR function. These results may explain the high conservation of a serine at this site in vertebrates, as well as provide an example of a tradeoff between beneficial and deleterious effects of an evolutionary change. They also provide important clues for future work on assembly and trafficking of this important neurotransmitter receptor.
Collapse
|
5
|
Moberg S, Takahashi N. Neocortical layer 5 subclasses: From cellular properties to roles in behavior. Front Synaptic Neurosci 2022; 14:1006773. [PMID: 36387773 PMCID: PMC9650089 DOI: 10.3389/fnsyn.2022.1006773] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/28/2022] [Indexed: 09/08/2024] Open
Abstract
Layer 5 (L5) serves as the main output layer of cortical structures, where long-range projecting pyramidal neurons broadcast the columnar output to other cortical and extracortical regions of the brain. L5 pyramidal neurons are grouped into two subclasses based on their projection targets; while intratelencephalic (IT) neurons project to cortical areas and the striatum, extratelencephalic (ET) neurons project to subcortical areas such as the thalamus, midbrain, and brainstem. Each L5 subclass possesses distinct morphological and electrophysiological properties and is incorporated into a unique synaptic network. Thanks to recent advances in genetic tools and methodologies, it has now become possible to distinguish between the two subclasses in the living brain. There is increasing evidence indicating that each subclass plays a unique role in sensory processing, decision-making, and learning. This review first summarizes the anatomical and physiological properties as well as the neuromodulation of IT and ET neurons in the rodent neocortex, and then reviews recent literature on their roles in sensory processing and rodent behavior. Our ultimate goal is to provide a comprehensive understanding of the role of each subclass in cortical function by examining their operational regimes based on their cellular properties.
Collapse
Affiliation(s)
- Sara Moberg
- Einstein Center for Neurosciences Berlin, Berlin, Germany
| | - Naoya Takahashi
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| |
Collapse
|
6
|
Liu C, Tose AJ, Verharen JPH, Zhu Y, Tang LW, de Jong JW, Du JX, Beier KT, Lammel S. An inhibitory brainstem input to dopamine neurons encodes nicotine aversion. Neuron 2022; 110:3018-3035.e7. [PMID: 35921846 PMCID: PMC9509462 DOI: 10.1016/j.neuron.2022.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 05/16/2022] [Accepted: 07/06/2022] [Indexed: 01/07/2023]
Abstract
Nicotine stimulates the dopamine (DA) system, which is essential for its rewarding effect. Nicotine is also aversive at high doses; yet, our knowledge about nicotine's dose-dependent effects on DA circuits remains limited. Here, we demonstrate that high doses of nicotine, which induce aversion-related behavior in mice, cause biphasic inhibitory and excitatory responses in VTA DA neurons that can be dissociated by distinct projections to lateral and medial nucleus accumben subregions, respectively. Guided by computational modeling, we performed a pharmacological investigation to establish that inhibitory effects of aversive nicotine involve desensitization of α4β2 and activation of α7 nicotinic acetylcholine receptors. We identify α7-dependent activation of upstream GABA neurons in the laterodorsal tegmentum (LDT) as a key regulator of heterogeneous DA release following aversive nicotine. Finally, inhibition of LDT GABA terminals in VTA prevents nicotine aversion. Together, our findings provide a mechanistic circuit-level understanding of nicotine's dose-dependent effects on reward and aversion.
Collapse
Affiliation(s)
- Christine Liu
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA
| | - Amanda J Tose
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA
| | - Jeroen P H Verharen
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA
| | - Yichen Zhu
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA
| | - Lilly W Tang
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA
| | - Johannes W de Jong
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA
| | - Jessica X Du
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA
| | - Kevin T Beier
- Department of Physiology and Biophysics, University of California Irvine, 825 Health Sciences Road, Med Sci D320, Irvine, CA 92697, USA
| | - Stephan Lammel
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, California, Berkeley, CA 94720, USA.
| |
Collapse
|
7
|
Marrero-Cristobal G, Gelpi-Dominguez U, Morales-Silva R, Alvarado-Torres J, Perez-Torres J, Perez-Perez Y, Sepulveda-Orengo M. Aerobic exercise as a promising nonpharmacological therapy for the treatment of substance use disorders. J Neurosci Res 2022; 100:1602-1642. [PMID: 34850988 PMCID: PMC9156662 DOI: 10.1002/jnr.24990] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 10/06/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022]
Abstract
Despite the prevalence and public health impact of substance use disorders (SUDs), effective long-term treatments remain elusive. Aerobic exercise is a promising, nonpharmacological treatment currently under investigation as a strategy for preventing drug relapse. Aerobic exercise could be incorporated into the comprehensive treatment regimens for people with substance abuse disorders. Preclinical studies of SUD with animal models have shown that aerobic exercise diminishes drug-seeking behavior, which leads to relapse, in both male and female rats. Nevertheless, little is known regarding the effects of substance abuse-induced cellular and physiological adaptations believed to be responsible for drug-seeking behavior. Accordingly, the overall goal of this review is to provide a summary and an assessment of findings to date, highlighting evidence of the molecular and neurological effects of exercise on adaptations associated with SUD.
Collapse
Affiliation(s)
| | - Ursula Gelpi-Dominguez
- School of Behavioral and Brain Sciences, Ponce Health Sciences University, Ponce, PR, USA
| | - Roberto Morales-Silva
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, PR, USA
| | - John Alvarado-Torres
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, PR, USA
| | - Joshua Perez-Torres
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, PR, USA
| | - Yobet Perez-Perez
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, PR, USA
| | - Marian Sepulveda-Orengo
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce, PR, USA
| |
Collapse
|
8
|
Meneghini S, Modena D, Colombo G, Coatti A, Milani N, Madaschi L, Amadeo A, Becchetti A. The β2V287L nicotinic subunit linked to sleep-related epilepsy differently affects fast-spiking and regular spiking somatostatin-expressing neurons in murine prefrontal cortex. Prog Neurobiol 2022; 214:102279. [DOI: 10.1016/j.pneurobio.2022.102279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 04/02/2022] [Accepted: 04/28/2022] [Indexed: 12/01/2022]
|
9
|
Olsson Y, Lidö H, Ericson M, Söderpalm B. The glycine-containing dipeptide leucine-glycine raises accumbal dopamine levels in a subpopulation of rats presenting a lower endogenous dopamine tone. J Neural Transm (Vienna) 2022; 129:395-407. [PMID: 35322277 PMCID: PMC9007805 DOI: 10.1007/s00702-022-02487-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/09/2022] [Indexed: 11/26/2022]
Abstract
Interventions that elevate glycine levels and target the glycine receptor (GlyR) in the nucleus Accumbens (nAc) reduce ethanol intake in rats, supposedly by acting on the brain reward system via increased basal and attenuated ethanol-induced nAc dopamine release. Glycine transport across the blood brain barrier (BBB) appears inefficient, but glycine-containing dipeptides elevate whole brain tissue dopamine levels in mice. This study explores whether treatment with the glycine-containing dipeptides leucine-glycine (Leu-Gly) and glycine-leucine (Gly-Leu) by means of a hypothesized, facilitated BBB passage, alter nAc glycine and dopamine levels and locomotor activity in two rodent models. The acute effects of Leu-Gly and Gly-Leu (1–1000 mg/kg, i.p.) alone or Leu-Gly in combination with ethanol on locomotion in male NMRI mice were examined in locomotor activity boxes. Striatal and brainstem slices were obtained for ex vivo HPLC analyses of tissue levels of glycine and dopamine. Furthermore, the effects of Leu-Gly i.p. (1–1000 mg/kg) on glycine and dopamine output in the nAc were examined using in vivo microdialysis coupled to HPLC in freely moving male Wistar rats. Leu-Gly and Gly-Leu did not significantly alter locomotion, ethanol-induced hyperlocomotor activity or tissue levels of glycine or dopamine, apart from Gly-Leu 10 mg/kg that slightly raised nAc dopamine. Microdialysis revealed no significant alterations in nAc glycine or dopamine levels when regarding all rats as a homogenous group. In a subgroup of rats defined as dopamine responders, a significant elevation of nAc dopamine (20%) was seen following Leu-Gly 10–1000 mg/kg i.p, and this group of animals presented lower baseline dopamine levels compared to dopamine non-responders. To conclude, peripheral injection of glycine-containing dipeptides appears inefficient in elevating central glycine levels but raises accumbal dopamine levels in a subgroup of rats with a lower endogenous dopamine tone. The tentative relationship between dopamine baseline and ensuing response to glycinergic treatment and presumptive direct interactions between glycine-containing dipeptides and the GlyR bear insights for refinement of the glycinergic treatment concept for alcohol use disorder (AUD).
Collapse
Affiliation(s)
- Yasmin Olsson
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, PO Box 410, 405 30, Gothenburg, Sweden.
- Beroendekliniken, Sahlgrenska University Hospital, Gothenburg, Sweden.
- Department of Neurology, Sahlgrenska University Hospital, Gothenburg, Sweden.
| | - Helga Lidö
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, PO Box 410, 405 30, Gothenburg, Sweden
- Beroendekliniken, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Mia Ericson
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, PO Box 410, 405 30, Gothenburg, Sweden
| | - Bo Söderpalm
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, PO Box 410, 405 30, Gothenburg, Sweden
- Beroendekliniken, Sahlgrenska University Hospital, Gothenburg, Sweden
| |
Collapse
|
10
|
Canning BJ, Liu Q, Tao M, DeVita R, Perelman M, Hay DW, Dicpinigaitis PV, Liang J. Evidence for Alpha 7 Nicotinic Receptor Activation During the Cough Suppressing Effects Induced by Nicotine and Identification of ATA-101 as a Potential Novel Therapy for the Treatment of Chronic Cough. J Pharmacol Exp Ther 2022; 380:94-103. [PMID: 34782407 PMCID: PMC8969114 DOI: 10.1124/jpet.121.000641] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 11/11/2021] [Indexed: 02/03/2023] Open
Abstract
Studies performed in healthy smokers have documented a diminished responsiveness to tussive challenges, and several lines of experimental evidence implicate nicotine as an antitussive component in both cigarette smoke and the vapors generated by electronic cigarettes (eCigs). We set out to identify the nicotinic receptor subtype involved in the antitussive actions of nicotine and to further evaluate the potential of nicotinic receptor-selective agonists as cough-suppressing therapeutics. We confirmed an antitussive effect of nicotine in guinea pigs. We additionally observed that the alpha-4 beta-2 (α 4 β 2)-selective agonist Tc-6683 was without effect on evoked cough responses in guinea pigs, while the α 7-selective agonist PHA 543613 dose-dependently inhibited evoked coughing. We subsequently describe the preclinical evidence in support of ATA-101, a potent and highly selective (α 7) selective nicotinic receptor agonist, as a potential candidate for antitussive therapy in humans. ATA-101, formerly known as Tc-5619, was orally bioavailable and moderately central nervous system (CNS) penetrant and dose-dependently inhibited coughing in guinea pigs evoked by citric acid and bradykinin. Comparing the effects of airway targeted administration versus systemic dosing and the effects of repeated dosing at various times prior to tussive challenge, our data suggest that the antitussive actions of ATA-101 require continued engagement of α 7 nicotinic receptors, likely in the CNS. Collectively, the data provide the preclinical rationale for α 7 nicotinic receptor engagement as a novel therapeutic strategy for cough suppression. The data also suggest that α 7 nicotinic acetylcholine receptor (nAChR) activation by nicotine may be permissive to nicotine delivery in a way that may promote addiction. SIGNIFICANCE STATEMENT: This study documents the antitussive actions of nicotine and identifies the α7 nicotinic receptor subtype as the target for nicotine during cough suppression described in humans. We additionally present evidence suggesting that ATA-101 and other α7 nicotinic receptor-selective agonists may be promising candidates for the treatment of chronic refractory cough.
Collapse
Affiliation(s)
- Brendan J Canning
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| | - Qi Liu
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| | - Mayuko Tao
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| | - Robert DeVita
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| | - Michael Perelman
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| | - Douglas W Hay
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| | - Peter V Dicpinigaitis
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| | - Jing Liang
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (B.J.C, Q.L.); Tokyo Medical and Dental University, Tokyo, Japan (M.T.); RJD Medicinal Chemistry Consulting LLC, Westfield, New Jersey (R.D.); Michael Perelman Consulting, Winter Park, Florida (M.P.); Hay Drug Discovery Consulting, Valley Forge, Pennsylvania (D.W.H.); Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York (P.V.D.); Apple Helix Bioventures, New York, New York (J.L.)
| |
Collapse
|
11
|
Loser D, Grillberger K, Hinojosa MG, Blum J, Haufe Y, Danker T, Johansson Y, Möller C, Nicke A, Bennekou SH, Gardner I, Bauch C, Walker P, Forsby A, Ecker GF, Kraushaar U, Leist M. Acute effects of the imidacloprid metabolite desnitro-imidacloprid on human nACh receptors relevant for neuronal signaling. Arch Toxicol 2021; 95:3695-3716. [PMID: 34628512 PMCID: PMC8536575 DOI: 10.1007/s00204-021-03168-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/20/2021] [Indexed: 12/15/2022]
Abstract
Several neonicotinoids have recently been shown to activate the nicotinic acetylcholine receptor (nAChR) on human neurons. Moreover, imidacloprid (IMI) and other members of this pesticide family form a set of diverse metabolites within crops. Among these, desnitro-imidacloprid (DN-IMI) is of special toxicological interest, as there is evidence (i) for human dietary exposure to this metabolite, (ii) and that DN-IMI is a strong trigger of mammalian nicotinic responses. We set out here to quantify responses of human nAChRs to DN-IMI and an alternative metabolite, IMI-olefin. To evaluate toxicological hazards, these data were then compared to those of IMI and nicotine. Ca2+-imaging experiments on human neurons showed that DN-IMI exhibits an agonistic effect on nAChRs at sub-micromolar concentrations (equipotent with nicotine) while IMI-olefin activated the receptors less potently (in a similar range as IMI). Direct experimental data on the interaction with defined receptor subtypes were obtained by heterologous expression of various human nAChR subtypes in Xenopus laevis oocytes and measurement of the transmembrane currents evoked by exposure to putative ligands. DN-IMI acted on the physiologically important human nAChR subtypes α7, α3β4, and α4β2 (high-sensitivity variant) with similar potency as nicotine. IMI and IMI-olefin were confirmed as nAChR agonists, although with 2-3 orders of magnitude lower potency. Molecular docking studies, using receptor models for the α7 and α4β2 nAChR subtypes supported an activity of DN-IMI similar to that of nicotine. In summary, these data suggest that DN-IMI functionally affects human neurons similar to the well-established neurotoxicant nicotine by triggering α7 and several non-α7 nAChRs.
Collapse
Affiliation(s)
- Dominik Loser
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany
| | - Karin Grillberger
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Maria G Hinojosa
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Jonathan Blum
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany
| | - Yves Haufe
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336, Munich, Germany
| | - Timm Danker
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
| | - Ylva Johansson
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Clemens Möller
- Life Sciences Faculty, Albstadt-Sigmaringen University, 72488, Sigmaringen, Germany
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336, Munich, Germany
| | | | - Iain Gardner
- CERTARA UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Caroline Bauch
- Cyprotex Discovery Ltd, No. 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - Paul Walker
- Cyprotex Discovery Ltd, No. 24 Mereside, Alderley Park, Cheshire, SK10 4TG, UK
| | - Anna Forsby
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Gerhard F Ecker
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Udo Kraushaar
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457, Konstanz, Germany.
| |
Collapse
|
12
|
Neurotoxic Effects of Neonicotinoids on Mammals: What Is There beyond the Activation of Nicotinic Acetylcholine Receptors?-A Systematic Review. Int J Mol Sci 2021; 22:ijms22168413. [PMID: 34445117 PMCID: PMC8395098 DOI: 10.3390/ijms22168413] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 02/07/2023] Open
Abstract
Neonicotinoids are a class of insecticides that exert their effect through a specific action on neuronal nicotinic acetylcholine receptors (nAChRs). The success of these insecticides is due to this mechanism of action, since they act as potent agonists of insect nAChRs, presenting low affinity for vertebrate nAChRs, which reduces potential toxic risk and increases safety for non-target species. However, although neonicotinoids are considered safe, their presence in the environment could increase the risk of exposure and toxicity. On the other hand, although neonicotinoids have low affinity for mammalian nAChRs, the large quantity, variety, and ubiquity of these receptors, combined with its diversity of functions, raises the question of what effects these insecticides can produce in non-target species. In the present systematic review, we investigate the available evidence on the biochemical and behavioral effects of neonicotinoids on the mammalian nervous system. In general, exposure to neonicotinoids at an early age alters the correct neuronal development, with decreases in neurogenesis and alterations in migration, and induces neuroinflammation. In adulthood, neonicotinoids induce neurobehavioral toxicity, these effects being associated with their modulating action on nAChRs, with consequent neurochemical alterations. These alterations include decreased expression of nAChRs, modifications in acetylcholinesterase activity, and significant changes in the function of the nigrostriatal dopaminergic system. All these effects can lead to the activation of a series of intracellular signaling pathways that generate oxidative stress, neuroinflammation and, finally, neuronal death. Neonicotinoid-induced changes in nAChR function could be responsible for most of the effects observed in the different studies.
Collapse
|
13
|
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: 30] [Impact Index Per Article: 10.0] [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.
Collapse
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
| |
Collapse
|
14
|
Izumi S, Domoto M, Esaki H, Sasase H, Nishitani N, Deyama S, Kaneda K. Nicotine Enhances Firing Activity of Layer 5 Pyramidal Neurons in the Medial Prefrontal Cortex through Inhibition of Kv7 Channels. Biol Pharm Bull 2021; 44:724-731. [PMID: 33952828 DOI: 10.1248/bpb.b21-00137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nicotine enhances attention, working memory and recognition. One of the brain regions associated with these effects of nicotine is the medial prefrontal cortex (mPFC). However, cellular mechanisms that induce the enhancing effects of nicotine remain unclear. To address this issue, we performed whole-cell patch-clamp recordings from mPFC layer 5 pyramidal neurons in slices of C57BL/6J mice. Shortly (approx. 2 min) after bath application of nicotine, the number of action potentials, which were elicited by depolarizing current injection, was increased, and this increase persisted for over 5 min. The effect of nicotine was blocked by the α4β2 nicotinic acetylcholine receptor (nAChR) antagonist dihydro-β-erythroidine, α7 nAChR antagonist methyllycaconitine, or intracellular perfusion with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Additionally, the voltage-dependent potassium 7 (Kv7) channel blocker, 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone dihydrochloride (XE-991), as well as nicotine, shortened the spike threshold latency and increased the spike numbers. By contrast, the Kv7 channel opener, retigabine reduced the number of firings, and the addition of nicotine did not increase the spike numbers. These results indicate that nicotine induces long-lasting enhancement of firing activity in mPFC layer 5 pyramidal neurons, which is mediated by the stimulation of the α4β2 and α7 nAChRs and subsequent increase in intracellular Ca2+ levels followed by the suppression of the Kv7 channels. The novel effect of nicotine might underlie the nicotine-induced enhancement of attention, working memory and recognition.
Collapse
Affiliation(s)
- Shoma Izumi
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Masaki Domoto
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Hirohito Esaki
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Hitoki Sasase
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Naoya Nishitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Satoshi Deyama
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| |
Collapse
|
15
|
Loser D, Hinojosa MG, Blum J, Schaefer J, Brüll M, Johansson Y, Suciu I, Grillberger K, Danker T, Möller C, Gardner I, Ecker GF, Bennekou SH, Forsby A, Kraushaar U, Leist M. Functional alterations by a subgroup of neonicotinoid pesticides in human dopaminergic neurons. Arch Toxicol 2021; 95:2081-2107. [PMID: 33778899 PMCID: PMC8166715 DOI: 10.1007/s00204-021-03031-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/17/2021] [Indexed: 12/16/2022]
Abstract
Neonicotinoid pesticides, originally developed to target the insect nervous system, have been reported to interact with human receptors and to activate rodent neurons. Therefore, we evaluated in how far these compounds may trigger signaling in human neurons, and thus, affect the human adult or developing nervous system. We used SH-SY5Y neuroblastoma cells as established model of nicotinic acetylcholine receptor (nAChR) signaling. In parallel, we profiled dopaminergic neurons, generated from LUHMES neuronal precursor cells, as novel system to study nAChR activation in human post-mitotic neurons. Changes of the free intracellular Ca2+ concentration ([Ca2+]i) were used as readout, and key findings were confirmed by patch clamp recordings. Nicotine triggered typical neuronal signaling responses that were blocked by antagonists, such as tubocurarine and mecamylamine. Pharmacological approaches suggested a functional expression of α7 and non-α7 nAChRs on LUHMES cells. In this novel test system, the neonicotinoids acetamiprid, imidacloprid, clothianidin and thiacloprid, but not thiamethoxam and dinotefuran, triggered [Ca2+]i signaling at 10-100 µM. Strong synergy of the active neonicotinoids (at low micromolar concentrations) with the α7 nAChR-positive allosteric modulator PNU-120596 was observed in LUHMES and SH-SY5Y cells, and specific antagonists fully inhibited such signaling. To provide a third line of evidence for neonicotinoid signaling via nAChR, we studied cross-desensitization: pretreatment of LUHMES and SH-SY5Y cells with active neonicotinoids (at 1-10 µM) blunted the signaling response of nicotine. The pesticides (at 3-30 µM) also blunted the response to the non-α7 agonist ABT 594 in LUHMES cells. These data show that human neuronal cells are functionally affected by low micromolar concentrations of several neonicotinoids. An effect of such signals on nervous system development is a toxicological concern.
Collapse
Affiliation(s)
- Dominik Loser
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Maria G Hinojosa
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Jonathan Blum
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Jasmin Schaefer
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
| | - Markus Brüll
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Ylva Johansson
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Ilinca Suciu
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany
| | - Karin Grillberger
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Timm Danker
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
| | - Clemens Möller
- Life Sciences Faculty, Albstadt-Sigmaringen University, 72488, Sigmaringen, Germany
| | - Iain Gardner
- CERTARA UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Gerhard F Ecker
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | | | - Anna Forsby
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Udo Kraushaar
- NMI Natural and Medical Sciences Institute at the University of Tübingen, 72770, Reutlingen, Germany
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Konstanz, Germany.
| |
Collapse
|
16
|
Brynildsen JK, Blendy JA. Linking the CHRNA5 SNP to drug abuse liability: From circuitry to cellular mechanisms. Neuropharmacology 2021; 186:108480. [PMID: 33539855 PMCID: PMC7958463 DOI: 10.1016/j.neuropharm.2021.108480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/10/2020] [Accepted: 01/28/2021] [Indexed: 10/22/2022]
Abstract
Genetics are known to be a significant risk factor for drug abuse. In human populations, the single nucleotide polymorphism (SNP) D398N in the gene CHRNA5 has been associated with addiction to nicotine, opioids, cocaine, and alcohol. In this paper, we review findings from studies in humans, rodent models, and cell lines and provide evidence that collectively suggests that the Chrna5 SNP broadly influences the response to drugs of abuse in a manner that is not substance-specific. This finding has important implications for our understanding of the role of the cholinergic system in reward and addiction vulnerability. This article is part of the special issue on 'Vulnerabilities to Substance Abuse.'
Collapse
Affiliation(s)
- Julia K Brynildsen
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Julie A Blendy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| |
Collapse
|
17
|
Fernandes TP, Almeida NL, Silva GM, Santos NA. Nicotine gum enhances visual processing in healthy nonsmokers. Brain Imaging Behav 2021; 15:2593-2605. [PMID: 33675460 DOI: 10.1007/s11682-021-00461-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2021] [Indexed: 10/22/2022]
Abstract
OBJECTIVE The main purpose of this study was to investigate the isolated effects of nicotine on visual processing, namely contrast processing. METHODS Thirteen participants, aged 18-40 years, were enrolled in this double blind, randomized and pilot controlled trial involving nicotine gum administration (placebo, 2-mg and 4-mg doses). The participants' instruction was to detect the location of vertical gratings (0.2; 1.0; 3.3; 5.7; 8.8; 13.2 and 15.9 cycles per degree) when it was presented either left or right on the monitor screen. A repeated multivariate analysis of variance was conducted to analyse the results for the visual processing tasks. Bayesian analyses were also carried out considering maximum robustness to avoid bias. RESULTS The findings that nicotine gum administration resulted in better contrast discrimination when compared to placebo gum (p < .001). More specifically, the 4-mg resulted in better visual sensitivity when compared to the 2-mg (p < .01) and the placebo (p < .001) gum. Demographic data were not related to the outcomes. CONCLUSIONS These data bring the need for support the findings. If proved, it is possible that nicotine, in small doses, can have a potential therapeutic use for those populations with low vision. TRIAL REGISTRATION NUMBER RBR-46tjy3.
Collapse
Affiliation(s)
- Thiago P Fernandes
- Federal University of Paraiba, Joao Pessoa, Brazil. .,Perception, Neuroscience and Behaviour Laboratory, Federal University of Paraiba, Joao Pessoa, Brazil.
| | - Natalia L Almeida
- Federal University of Paraiba, Joao Pessoa, Brazil. .,Perception, Neuroscience and Behaviour Laboratory, Federal University of Paraiba, Joao Pessoa, Brazil.
| | - Gabriella M Silva
- Federal University of Paraiba, Joao Pessoa, Brazil.,Perception, Neuroscience and Behaviour Laboratory, Federal University of Paraiba, Joao Pessoa, Brazil
| | - Natanael A Santos
- Federal University of Paraiba, Joao Pessoa, Brazil.,Perception, Neuroscience and Behaviour Laboratory, Federal University of Paraiba, Joao Pessoa, Brazil
| |
Collapse
|
18
|
Shreckengost J, Halder M, Mena-Avila E, Garcia-Ramirez DL, Quevedo J, Hochman S. Nicotinic receptor modulation of primary afferent excitability with selective regulation of Aδ-mediated spinal actions. J Neurophysiol 2020; 125:568-585. [PMID: 33326305 DOI: 10.1152/jn.00228.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Somatosensory input strength can be modulated by primary afferent depolarization (PAD) generated predominantly via presynaptic GABAA receptors on afferent terminals. We investigated whether ionotropic nicotinic acetylcholine receptors (nAChRs) also provide modulatory actions, focusing on myelinated afferent excitability in in vitro murine spinal cord nerve-attached models. Primary afferent stimulation-evoked synaptic transmission was recorded in the deep dorsal horn as extracellular field potentials (EFPs), whereas concurrently recorded dorsal root potentials (DRPs) were used as an indirect measure of PAD. Changes in afferent membrane excitability were simultaneously measured as direct current (DC)-shifts in membrane polarization recorded in dorsal roots or peripheral nerves. The broad nAChR antagonist d-tubocurarine (d-TC) selectively and strongly depressed Aδ-evoked synaptic EFPs (36% of control) coincident with similarly depressed A-fiber DRP (43% of control), whereas afferent electrical excitability remained unchanged. In comparison, acetylcholine (ACh) and the nAChR agonists, epibatidine and nicotine, reduced afferent excitability by generating coincident depolarizing DC-shifts in peripheral axons and intraspinally. Progressive depolarization corresponded temporally with the emergence of spontaneous axonal spiking and reductions in the DRP and all afferent-evoked synaptic actions (31%-37% of control). Loss of evoked response was long-lasting, independent of DC repolarization, and likely due to mechanisms initiated by spontaneous C-fiber activity. DC-shifts were blocked with d-TC but not GABAA receptor blockers and retained after tetrodotoxin block of voltage-gated Na+ channels. Notably, actions tested were comparable between three mouse strains, in rat, and when performed in different labs. Thus, nAChRs can regulate afferent excitability via two distinct mechanisms: by central Aδ-afferent actions, and by transient extrasynaptic axonal activation of high-threshold primary afferents.NEW & NOTEWORTHY Primary afferents express many nicotinic ACh receptor (nAChR) subtypes but whether activation is linked to presynaptic inhibition, facilitation, or more complex and selective activity modulation is unknown. Recordings of afferent-evoked responses in the lumbar spinal cord identified two nAChR-mediated modulatory actions: 1) selective control of Aδ afferent transmission and 2) robust changes in axonal excitability initiated via extrasynaptic shifts in DC polarization. This work broadens the diversity of presynaptic modulation of primary afferents by nAChRs.
Collapse
Affiliation(s)
| | - Mallika Halder
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Elvia Mena-Avila
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - David Leonardo Garcia-Ramirez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Jorge Quevedo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Shawn Hochman
- Department of Physiology, Emory University, Atlanta, Georgia
| |
Collapse
|
19
|
Calarco CA, Picciotto MR. Nicotinic Acetylcholine Receptor Signaling in the Hypothalamus: Mechanisms Related to Nicotine's Effects on Food Intake. Nicotine Tob Res 2020; 22:152-163. [PMID: 30690485 DOI: 10.1093/ntr/ntz010] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
Abstract
Despite health risks associated with smoking, up to 20% of the US population persist in this behavior; many smoke to control body weight or appetite, and fear of post-cessation weight gain can motivate continued smoking. Nicotine and tobacco use is associated with lower body weight, and cessation yields an average weight gain of about 4 kg, which is thought to reflect a return to the body weight of a typical nonsmoker. Nicotine replacement therapies can delay this weight gain but do not prevent it altogether, and the underlying mechanism for how nicotine is able to reduce weight is not fully understood. In rodent models, nicotine reduces weight gain, reduces food consumption, and alters energy expenditure, but these effects vary with duration and route of nicotine administration. Nicotine, acting through nicotinic acetylcholine receptors (nAChRs), increases the firing rate of both orexigenic agouti-related peptide and anorexigenic proopiomelanocortin neurons in the arcuate nucleus of the hypothalamus (ARC). Manipulation of nAChR subunit expression within the ARC can block the ability of nicotine and the nicotinic agonist cytisine from decreasing food intake; however, it is unknown exactly how this reduces food intake. This review summarizes the clinical and preclinical work on nicotine, food intake, and weight gain, then explores the feeding circuitry of the ARC and how it is regulated by nicotine. Finally, we propose a novel hypothesis for how nicotine acts on this hypothalamic circuit to reduce food intake. Implications: This review provides a comprehensive and updated summary of the clinical and preclinical work examining nicotine and food intake, as well as a summary of recent work examining feeding circuits of the hypothalamus. Synthesis of these two topics has led to new understanding of how nAChR signaling regulates food intake circuits in the hypothalamus.
Collapse
Affiliation(s)
- Cali A Calarco
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT.,Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT
| | - Marina R Picciotto
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT.,Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT
| |
Collapse
|
20
|
Bertrand D, Wallace TL. A Review of the Cholinergic System and Therapeutic Approaches to Treat Brain Disorders. Curr Top Behav Neurosci 2020; 45:1-28. [PMID: 32451956 DOI: 10.1007/7854_2020_141] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Since its identification over a hundred years ago, the neurotransmitter acetylcholine (ACh) has proven to play an essential role in supporting many diverse functions. Some well-characterized functions include: chemical transmission at the neuromuscular junction; autonomic function in the peripheral nervous system; and, sustained attention, sleep/wake regulation, and learning and memory within the central nervous system. Within the brain, major cholinergic projection pathways from the basal forebrain and the brainstem support these centrally mediated processes, and dysregulation of the cholinergic system is implicated in cognitive decline associated with aging and dementias including Alzheimer's disease. ACh exerts its effects by binding to two different membrane-bound receptor classes: (1) G‑protein coupled muscarinic acetylcholine receptors (mAChRs), and (2) ligand-gated nicotinic acetylcholine receptors (nAChRs). These receptor systems are described in detail within this chapter along with discussion on the successes and failures of synthetic ligands designed to selectively target receptor subtypes for treating brain disorders. New molecular approaches and advances in our understanding of the target biology combined with opportunities to re-purpose existing cholinergic drugs for new indications continue to highlight the exciting opportunities for modulating this system for therapeutic purposes.
Collapse
|
21
|
Nicotinic Receptors Underlying Nicotine Dependence: Evidence from Transgenic Mouse Models. Curr Top Behav Neurosci 2020; 45:101-121. [PMID: 32468493 DOI: 10.1007/7854_2020_134] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nicotine underlies the reinforcing properties of tobacco cigarettes and e-cigarettes. After inhalation and absorption, nicotine binds to various nicotinic acetylcholine receptor (nAChR) subtypes localized on the pre- and postsynaptic membranes of cells, which subsequently leads to the modulation of cellular function and neurotransmitter signaling. In this chapter, we begin by briefly reviewing the current understanding of nicotine's actions on nAChRs and highlight considerations regarding nAChR subtype localization and pharmacodynamics. Thereafter, we discuss the seminal discoveries derived from genetically modified mouse models, which have greatly contributed to our understanding of nicotine's effects on the reward-related mesolimbic pathway and the aversion-related habenulo-interpeduncular pathway. Thereafter, emerging areas of research focusing on modulation of nAChR expression and/or function are considered. Taken together, these discoveries have provided a foundational understanding of various genetic, neurobiological, and behavioral factors underlying the motivation to use nicotine and related dependence processes, which are thereby advancing drug discovery efforts to promote long-term abstinence.
Collapse
|
22
|
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.
Collapse
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.
| |
Collapse
|
23
|
Cuevas-Olguin R, Esquivel-Rendon E, Vargas-Mireles J, Barajas-Lόpez C, Salgado-Delgado R, Saderi N, Arias HR, Atzori M, Miranda-Morales M. Nicotine smoking concentrations modulate GABAergic synaptic transmission in murine medial prefrontal cortex by activation of α7* and β2* nicotinic receptors. Eur J Neurosci 2019; 51:781-792. [PMID: 31613395 DOI: 10.1111/ejn.14595] [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: 03/31/2018] [Revised: 09/23/2019] [Accepted: 10/14/2019] [Indexed: 01/22/2023]
Abstract
Nicotine is the major addictive component of cigarettes, reaching a brain concentration of ~300 nM during smoking of a single cigarette. The prefrontal cortex (PFC) mechanisms underlying temporary changes of working memory during smoking are incompletely understood. Here, we investigated whether 300 nM nicotine modulates γ-aminobutyric acid (GABA) ergic synaptic transmission from pyramidal neurons of the output layer (V) of the murine medial PFC. We used patch clamp in vitro recording from C57BL/6 mice in the whole-cell configuration to investigate the effect of nicotine on pharmacologically isolated GABAergic postsynaptic currents (IPSCs) in the absence or presence of methyllycaconitine (MLA) or dihydro-β-erythroidine (DHβE), selective antagonists of α7- and β2-containing (α7* and β2*) nicotinic acetylcholine receptors (AChRs), respectively. Our results indicated that nicotine, alone or in the presence of MLA, decreases electrically evoked IPSC (eIPSC) amplitude, whereas in the presence of DHβE, nicotine elicited either an eIPSCs amplitude increase or a decrease. In the presence of DHβE, nicotine increased membrane conductance leaving the paired pulse ratio unchanged in all conditions, suggesting a non-β2* mediated effect. In the presence of MLA, nicotine decreased the mean spontaneous IPSC (sIPSC) frequency but increased their rise time, suggesting a non-α7* AChR-mediated synaptic modulation. Also, in the presence of DHβE, nicotine decreased both eIPSC rise and decay times. No receptors other than α7* and β2* appear to be involved in the nicotine effect. Our results indicate that nicotine smoking concentrations modulate GABAergic synaptic currents through mixed pre- and post-synaptic mechanisms by activation of α7* and β2* AChRs.
Collapse
Affiliation(s)
- Roberto Cuevas-Olguin
- Faculty of Science, Universidad Autónoma de San Luis Potosí, San Luis potosí, México
| | - Eric Esquivel-Rendon
- Faculty of Science, Universidad Autónoma de San Luis Potosí, San Luis potosí, México
| | - Jorge Vargas-Mireles
- Faculty of Science, Universidad Autónoma de San Luis Potosí, San Luis potosí, México
| | - Carlos Barajas-Lόpez
- División de Biología Molecular, Instituto de Investigación Científica y Tecnológica, San Luis Potosí, México
| | | | - Nadia Saderi
- Faculty of Science, Universidad Autónoma de San Luis Potosí, San Luis potosí, México
| | - Hugo R Arias
- Department of Pharmacology and Physiology, College of Osteopathic Medicine, Oklahoma State University Center for Health Sciences, Tahlequah, OK, USA
| | - Marco Atzori
- Faculty of Science, Universidad Autónoma de San Luis Potosí, San Luis potosí, México
| | | |
Collapse
|
24
|
Ugur M, Kanit L, Koylu EO, Balkan B, Gözen O. Cocaine- and amphetamine-regulated transcript promoter regulated by nicotine in nerve growth factor-treated PC12 cells. Physiol Int 2019; 106:272-282. [DOI: 10.1556/2060.106.2019.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Nicotine and cocaine- and amphetamine-regulated transcripts (CART) have several overlapping functions, such as the regulation of reward, feeding behavior, stress response, and anxiety. Previous studies showed that nicotine regulates CART expression in various brain regions. However, the molecular mechanisms underlying this regulation are not known. This study investigated the regulatory effect of nicotine on promoter activity of the CART gene in PC12 cells, which were differentiated into a neuronal phenotype by nerve growth factor (NGF) treatment. Two vectors containing reporter genes (Gaussia luciferase or mCherry) and the 1,140-bp upstream of the transcriptional start site of the mouse CART gene are used to analyze the CART promoter activity. Transient transfection of PC12 cells with either vector displayed strong promoter activity in both undifferentiated and differentiated PC12 cells. CART promoter activity in the PC12 cell line is increased by forskolin or NGF treatment. In differentiated PC12 cells, exposure to 50 nM nicotine for 6 h increased CART promoter activity. However, treatment with higher nicotine doses for 6 h and treatment with all nicotine doses for 24 h showed no effect. A nicotine concentration of 50 nM is comparable to brain nicotine levels experienced by chronic smokers over long periods of time. Taken together, these data indicate that nicotine may exert some of its actions through the regulation of CART transcription in the brain.
Collapse
Affiliation(s)
- M Ugur
- 1 Department of Physiology, Ege University School of Medicine, Izmir, Turkey
| | - L Kanit
- 1 Department of Physiology, Ege University School of Medicine, Izmir, Turkey
- 2 Ege University Center for Brain Research, Izmir, Turkey
| | - EO Koylu
- 1 Department of Physiology, Ege University School of Medicine, Izmir, Turkey
- 2 Ege University Center for Brain Research, Izmir, Turkey
| | - B Balkan
- 1 Department of Physiology, Ege University School of Medicine, Izmir, Turkey
- 2 Ege University Center for Brain Research, Izmir, Turkey
| | - O Gözen
- 1 Department of Physiology, Ege University School of Medicine, Izmir, Turkey
- 2 Ege University Center for Brain Research, Izmir, Turkey
| |
Collapse
|
25
|
Waeiss RA, Knight CP, Carvajal GB, Bell RL, Engleman EA, McBride WJ, Hauser SR, Rodd ZA. Peri-adolescent alcohol consumption increases sensitivity and dopaminergic response to nicotine during adulthood in female alcohol-preferring (P) rats: Alterations to α7 nicotinic acetylcholine receptor expression. Behav Brain Res 2019; 376:112190. [PMID: 31473285 DOI: 10.1016/j.bbr.2019.112190] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/05/2019] [Accepted: 08/28/2019] [Indexed: 12/11/2022]
Abstract
Adolescent alcohol drinking has been linked to increased risk for drug abuse during adulthood. Nicotine microinjected directly into the posterior ventral tegmental area (pVTA) stimulates dopamine (DA) release in the nucleus accumbens (NAc) shell. The α7 nicotinic acetylcholine receptor (nAChR) is a potent regulator of dopaminergic activity in the pVTA. The current experiments examined the effects of peri-adolescent ethanol (EtOH) drinking on the ability of intra-pVTA nicotine to stimulate DA release during adulthood and alterations in α7 nAChR expression within the pVTA. Alcohol-preferring (P) female rats consumed EtOH and/or water during adolescence (post-natal day [PND] 30-60) or adulthood (PND 90-120). Thirty days following removal of EtOH, subjects received microinjections of 1 μM, 10 μM, or 50 μM nicotine into the pVTA concurrently with microdialysis for extracellular DA in the NAc shell. Brains were harvested from an additional cohort after PND 90 for quantification of α7 nAChR within the pVTA. The results indicated that only adolescent EtOH consumption produced a leftward and upward shift in the dose response curve for nicotine to stimulate DA release in the NAc shell. Investigation of α7 nAChR expression within the pVTA revealed a significant increase in animals that consumed EtOH during adolescence compared to naïve animals. The data suggests that peri-adolescent EtOH consumption produced cross-sensitization to the effects of nicotine during adulthood. The interaction between adolescent EtOH consumption and inflated adult risk for drug dependency could be predicated, at least in part, upon alterations in α7 nAChR expression within the mesolimbic reward pathway.
Collapse
Affiliation(s)
- Robert A Waeiss
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States.
| | - Christopher P Knight
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Gustavo B Carvajal
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Richard L Bell
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Eric A Engleman
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - William J McBride
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Sheketha R Hauser
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Zachary A Rodd
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| |
Collapse
|
26
|
Alkam T, Nabeshima T. Molecular mechanisms for nicotine intoxication. Neurochem Int 2019; 125:117-126. [PMID: 30779928 DOI: 10.1016/j.neuint.2019.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/28/2019] [Accepted: 02/12/2019] [Indexed: 01/25/2023]
Abstract
Nicotine, one of the more than 4700 ingredients in tobacco smoke, is a neurotoxin and once used as pesticides in agriculture. Although its use in agriculture is prohibited in many countries, nicotine intoxication is still a problem among the workers in tobacco farms, and young children as well as adults due to the accidental or suicidal ingestions of nicotine products. Understanding the mechanism of nicotine intoxication is important not only for the prevention and treatment but also for the appropriate regulatory approaches. Here, we review pharmacokinetics of nicotine and the molecular mechanisms for acute and chronic intoxication from nicotine that might be relevant to the central and the peripheral nervous system. We include green tobacco sickness, acute intoxication from popular nicotine products, circadian rhythm changes, chronic intoxication from nicotine through prenatal nicotine exposure, newborn behaviors, and sudden infant death syndrome.
Collapse
Affiliation(s)
- Tursun Alkam
- Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan; Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, USA.
| | - Toshitaka Nabeshima
- Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan; Advanced Diagnostic System Research Laboratory, Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.
| |
Collapse
|
27
|
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.
Collapse
|
28
|
Halawa AA, Damborsky JC, Slaton GS, Winzer-Serhan UH. Activation of immediate early genes by nicotine after chronic neonatal nicotine exposure in brain areas involved in stress and anxiety responses. Brain Res 2018; 1687:32-40. [DOI: 10.1016/j.brainres.2018.02.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/16/2018] [Accepted: 02/18/2018] [Indexed: 12/29/2022]
|
29
|
Abstract
Nicotine is the addictive compound in tobacco products which exerts psychosomatic effects that contribute to abuse and to low rates of abstinence in treatment-seeking smokers. At present, the most successful smoking cessation aide helps one in four individuals quit smoking at 1 year postcessation. New adjunctive therapies are needed to improve status of smoking-related public health crises, and β-lactam antibiotics are one class of potential therapies as they favorably augment extrasynaptic glutamate clearance. Our study used two-chamber place conditioning to assess effects of ceftriaxone (CTX) on persistence of conditioned nicotine reward. Rats were conditioned to associate nicotine (0.4 mg/kg, subcutaneous) with one context and vehicle with an alternative context. After initial post-test, rats received either daily ceftriaxone (200 mg/kg, intraperitoneal) or saline. All rats showed nicotine place preference during post-test 1. CTX-treated rats meeting extinction criterion by post-test 7 showed significantly reduced preference for the nicotine-paired context during post-test 2 compared with vehicle-treated rats. We interpret these data to support the further study of CTX as a smoking cessation aide. Our results suggest that CTX reduces persistence of conditioned nicotine reward and may be helpful for improving abstinence rates in a subset of treatment-seeking smokers.
Collapse
|
30
|
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.
Collapse
|
31
|
Dumont G, Maex R, Gutkin B. Dopaminergic Neurons in the Ventral Tegmental Area and Their Dysregulation in Nicotine Addiction. COMPUTATIONAL PSYCHIATRY 2018. [DOI: 10.1016/b978-0-12-809825-7.00003-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
32
|
Abreu-Villaça Y, Manhães AC, Krahe TE, Filgueiras CC, Ribeiro-Carvalho A. Tobacco and alcohol use during adolescence: Interactive mechanisms in animal models. Biochem Pharmacol 2017; 144:1-17. [DOI: 10.1016/j.bcp.2017.06.113] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/05/2017] [Indexed: 12/13/2022]
|
33
|
Nicotine and networks: Potential for enhancement of mood and cognition in late-life depression. Neurosci Biobehav Rev 2017; 84:289-298. [PMID: 28859996 DOI: 10.1016/j.neubiorev.2017.08.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/11/2017] [Accepted: 08/25/2017] [Indexed: 11/23/2022]
Abstract
Late-life depression is characterized by both lower mood and poor cognitive performance, symptoms that often do not fully respond to current antidepressant medications. Nicotinic acetylcholine receptor (nAChR) agonists such as nicotine may serve as a novel therapeutic approach for this population. Both preclinical and preliminary clinical studies suggest that nAChR agonists can improve depressive behavior in animal models and improve mood in depressed individuals. Substantial literature also supports that nAChR agonists benefit cognitive performance, particularly in older populations. These potential benefits may be mediated by the effects of nAChR stimulation on neural network function and connectivity. Functional neuroimaging studies detail effects of nAChR agonists on the default mode network, central-executive network, and salience network that may oppose or reverse network changes seen in depression. We propose that, given the existent literature and the clinical presentation of late-life depression, nicotine or other nAChR agonists may have unique therapeutic benefits in this population and that clinical trials examining nicotine effects on mood, cognition, and network dynamics in late-life depression are justified.
Collapse
|
34
|
Compromised neuroplasticity in cigarette smokers under nicotine withdrawal is restituted by the nicotinic α 4β 2-receptor partial agonist varenicline. Sci Rep 2017; 7:1387. [PMID: 28469204 PMCID: PMC5431184 DOI: 10.1038/s41598-017-01428-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 03/29/2017] [Indexed: 11/08/2022] Open
Abstract
Nicotine modulates neuroplasticity and improves cognitive functions in animals and humans. In the brain of smoking individuals, calcium-dependent plasticity induced by non-invasive brain stimulation methods such as transcranial direct current stimulation (tDCS) and paired associative stimulation (PAS) is impaired by nicotine withdrawal, but partially re-established after nicotine re-administration. In order to investigate the underlying mechanism further, we tested the impact of the α4β2-nicotinic receptor partial agonist varenicline on focal and non-focal plasticity in smokers during nicotine withdrawal, induced by PAS and tDCS, respectively. We administered low (0.3 mg) and high (1.0 mg) single doses of varenicline or placebo medication before stimulation over the left motor cortex of 20 healthy smokers under nicotine withdrawal. Motor cortex excitability was monitored by single-pulse transcranial magnetic stimulation-induced motor evoked potential amplitudes for 36 hours after plasticity induction. Stimulation-induced plasticity was absent under placebo medication, whereas it was present in all conditions under high dose. Low dose restituted only tDCS-induced non-focal plasticity, producing no significant impact on focal plasticity. High dose varenicline also prolonged inhibitory plasticity. These results are comparable to the impact of nicotine on withdrawal-related impaired plasticity in smokers and suggest that α4β2 nicotinic receptors are relevantly involved in plasticity deficits and restitution in smokers.
Collapse
|
35
|
Chen X, Feng J, Hu C, Qin Q, Li Y, Qin L. Redistribution of adrenomedullary nicotinic acetylcholine receptor subunits and the effect on circulating epinephrine levels in a murine model of acute asthma. Int J Mol Med 2016; 39:337-346. [PMID: 28035367 PMCID: PMC5358715 DOI: 10.3892/ijmm.2016.2836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 12/16/2016] [Indexed: 01/02/2023] Open
Abstract
The lack of circulating epinephrine (EPI) in the pathogenesis of asthma has long been attributed to the lack of adrenergic nerves in human airways. However, in this study we considered that EPI levels are regulated by EPI release in addition to synthesis. Nicotinic acetylcholine receptors (nAChRs) have been shown to control EPI release, and we hypothesized that redistribution of nAChR subunits modulates EPI release and circulating EPI levels. Using a mouse model of asthma, circulating EPI levels were measured by enzyme-linked immunosorbent assays. Changes in the expression of nAChR subunits in the adrenal medulla were observed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. Expression of phenylethanolamine N-methyltransferase, tyrosine hydroxylase and galanin was detected by RT-qPCR. Lung pathology, airway resistance (RL) and EPI levels were also assessed after treatment with an α7 nAChR agonist or antagonist. α7 nAChR mRNA expression in the adrenal medulla was increased by more than 2-fold (P<0.05), and circulating EPI levels increased rapidly after treatment with the α7 nAChR agonist. These results indicated that increased EPI release, which was caused by the overexpression of α7 nAChR, was responsible for elevated circulating EPI levels. After treatment with an agonist of α7 nAChR, RL was significantly decreased. Serum corticosterone levels in individual mice were measured to rule out glucocorticoid as the main mediator of changes in EPI levels. On the whole, redistribution of nAChR subunits, primarily α7 nAChR, occurs in the adrenal medulla in asthmatic mice. Increased α7 nAChR expression can rapidly increase serum EPI levels and decrease airway responsiveness.
Collapse
Affiliation(s)
- Xi Chen
- Department of Respiratory Medicine, Xiangya Hospital, Central South University (Key Site of the National Clinical Research Center for Respiratory Disease), Changsha, Hunan 410008, P.R. China
| | - Juntao Feng
- Department of Respiratory Medicine, Xiangya Hospital, Central South University (Key Site of the National Clinical Research Center for Respiratory Disease), Changsha, Hunan 410008, P.R. China
| | - Chengping Hu
- Department of Respiratory Medicine, Xiangya Hospital, Central South University (Key Site of the National Clinical Research Center for Respiratory Disease), Changsha, Hunan 410008, P.R. China
| | - Qingwu Qin
- Department of Respiratory Medicine, Xiangya Hospital, Central South University (Key Site of the National Clinical Research Center for Respiratory Disease), Changsha, Hunan 410008, P.R. China
| | - Yuanyuan Li
- Department of Respiratory Medicine, Xiangya Hospital, Central South University (Key Site of the National Clinical Research Center for Respiratory Disease), Changsha, Hunan 410008, P.R. China
| | - Ling Qin
- Department of Respiratory Medicine, Xiangya Hospital, Central South University (Key Site of the National Clinical Research Center for Respiratory Disease), Changsha, Hunan 410008, P.R. China
| |
Collapse
|
36
|
Aracri P, Meneghini S, Coatti A, Amadeo A, Becchetti A. α4β2 ∗ nicotinic receptors stimulate GABA release onto fast-spiking cells in layer V of mouse prefrontal (Fr2) cortex. Neuroscience 2016; 340:48-61. [PMID: 27793780 PMCID: PMC5231322 DOI: 10.1016/j.neuroscience.2016.10.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 10/08/2016] [Accepted: 10/18/2016] [Indexed: 11/24/2022]
Abstract
α4β2∗ nAChRs stimulate IPSCs in FS interneurons, in layer V of the mouse PFC (Fr2). In P16–P63 mice, nicotine increased both IPSC and mIPSC frequencies. GABAergic terminals adjacent to PV+ cells expressed α4 nAChR. The percentage of FS cells with somatic α4β2∗ currents decreased with age. Hence, nAChRs may be able to induce local circuit disinhibition in Fr2 PFC.
Nicotinic acetylcholine receptors (nAChRs) produce widespread and complex effects on neocortex excitability. We studied how heteromeric nAChRs regulate inhibitory post-synaptic currents (IPSCs), in fast-spiking (FS) layer V neurons of the mouse frontal area 2 (Fr2). In the presence of blockers of ionotropic glutamate receptors, tonic application of 10 μM nicotine augmented the spontaneous IPSC frequency, with minor alterations of amplitudes and kinetics. These effects were studied since the 3rd postnatal week, and persisted throughout the first two months of postnatal life. The action of nicotine was blocked by 1 μM dihydro-β-erythroidine (DHβE; specific for α4∗ nAChRs), but not 10 nM methyllycaconitine (MLA; specific for α7∗ nAChRs). It was mimicked by 10 nM 5-iodo-3-[2(S)-azetidinylmethoxy]pyridine (5-IA; which activates β2∗ nAChRs). Similar results were obtained on miniature IPSCs (mIPSCs). Moreover, during the first five postnatal weeks, approximately 50% of FS cells displayed DHβE-sensitive whole-cell nicotinic currents. This percentage decreased to ∼5% in mice older than P45. By confocal microscopy, the α4 nAChR subunit was immunocytochemically identified on interneurons expressing either parvalbumin (PV), which mainly labels FS cells, or somatostatin (SOM), which labels the other major interneuron population in layer V. GABAergic terminals expressing α4 were observed to be juxtaposed to PV-positive (PV+) cells. A fraction of these terminals displayed PV immunoreactivity. We conclude that α4β2∗ nAChRs can produce sustained regulation of FS cells in Fr2 layer V. The effect presents a presynaptic component, whereas the somatic regulation decreases with age. These mechanisms may contribute to the nAChR-dependent stimulation of excitability during cognitive tasks as well as to the hyperexcitability caused by hyperfunctional heteromeric nAChRs in sleep-related epilepsy.
Collapse
Affiliation(s)
- Patrizia Aracri
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, piazza della Scienza 2, Milano 20126, Italy
| | - Simone Meneghini
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, piazza della Scienza 2, Milano 20126, Italy
| | - Aurora Coatti
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, piazza della Scienza 2, Milano 20126, Italy
| | - Alida Amadeo
- Department of Biosciences, University of Milano, Via Celoria 26, Milano 20133, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, piazza della Scienza 2, Milano 20126, Italy.
| |
Collapse
|
37
|
Neonicotinoid Insecticides Alter the Gene Expression Profile of Neuron-Enriched Cultures from Neonatal Rat Cerebellum. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:ijerph13100987. [PMID: 27782041 PMCID: PMC5086726 DOI: 10.3390/ijerph13100987] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/27/2016] [Indexed: 01/02/2023]
Abstract
Neonicotinoids are considered safe because of their low affinities to mammalian nicotinic acetylcholine receptors (nAChRs) relative to insect nAChRs. However, because of importance of nAChRs in mammalian brain development, there remains a need to establish the safety of chronic neonicotinoid exposures with regards to children's health. Here we examined the effects of longterm (14 days) and low dose (1 μM) exposure of neuron-enriched cultures from neonatal rat cerebellum to nicotine and two neonicotinoids: acetamiprid and imidacloprid. Immunocytochemistry revealed no differences in the number or morphology of immature neurons or glial cells in any group versus untreated control cultures. However, a slight disturbance in Purkinje cell dendritic arborization was observed in the exposed cultures. Next we performed transcriptome analysis on total RNAs using microarrays, and identified significant differential expression (p < 0.05, q < 0.05, ≥1.5 fold) between control cultures versus nicotine-, acetamiprid-, or imidacloprid-exposed cultures in 34, 48, and 67 genes, respectively. Common to all exposed groups were nine genes essential for neurodevelopment, suggesting that chronic neonicotinoid exposure alters the transcriptome of the developing mammalian brain in a similar way to nicotine exposure. Our results highlight the need for further careful investigations into the effects of neonicotinoids in the developing mammalian brain.
Collapse
|
38
|
Nicotinic receptor blockade decreases fos immunoreactivity within orexin/hypocretin-expressing neurons of nicotine-exposed rats. Behav Brain Res 2016; 314:226-33. [PMID: 27491589 DOI: 10.1016/j.bbr.2016.07.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/19/2016] [Accepted: 07/30/2016] [Indexed: 11/23/2022]
Abstract
Tobacco smoking is the leading cause of preventable death in the United States. Nicotine is the principal psychoactive ingredient in tobacco that causes addiction. The structures governing nicotine addiction, including those underlying withdrawal, are still being explored. Nicotine withdrawal is characterized by negative affective and cognitive symptoms that enhance relapse susceptibility, and suppressed dopaminergic transmission from ventral tegmental area (VTA) to target structures underlies behavioral symptoms of nicotine withdrawal. Agonist and partial agonist therapies help 1 in 4 treatment-seeking smokers at one-year post-cessation, and new targets are needed to more effectively aid smokers attempting to quit. Hypothalamic orexin/hypocretin neurons send excitatory projections to dopamine (DA)-producing neurons of VTA and modulate mesoaccumbal DA release. The effects of nicotinic receptor blockade, which is commonly used to precipitate withdrawal, on orexin neurons remain poorly investigated and present an attractive target for intervention. The present study sought to investigate the effects of nicotinic receptor blockade on hypothalamic orexin neurons using mecamylamine to precipitate withdrawal in rats. Separate groups of rats were treated with either chronic nicotine or saline for 7-days at which point effects of mecamylamine or saline on somatic signs and anxiety-like behavior were assessed. Finally, tissue from rats was harvested for immunofluorescent analysis of Fos within orexin neurons. Results demonstrate that nicotinic receptor blockade leads to reduced orexin cell activity, as indicated by lowered Fos-immunoreactivity, and suggest that this underlying cellular activity may be associated with symptoms of nicotine withdrawal as effects were most prominently observed in rats given chronic nicotine. We conclude from this study that orexin transmission becomes suppressed in rats upon nicotinic receptor blockade, and that behavioral symptoms associated with nicotine withdrawal may be aided by intervention upon orexinergic transmission.
Collapse
|
39
|
Grasing K. A threshold model for opposing actions of acetylcholine on reward behavior: Molecular mechanisms and implications for treatment of substance abuse disorders. Behav Brain Res 2016; 312:148-62. [PMID: 27316344 DOI: 10.1016/j.bbr.2016.06.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 06/11/2016] [Accepted: 06/13/2016] [Indexed: 12/26/2022]
Abstract
The cholinergic system plays important roles in both learning and addiction. Medications that modify cholinergic tone can have pronounced effects on behaviors reinforced by natural and drug reinforcers. Importantly, enhancing the action of acetylcholine (ACh) in the nucleus accumbens and ventral tegmental area (VTA) dopamine system can either augment or diminish these behaviors. A threshold model is presented that can explain these seemingly contradictory results. Relatively low levels of ACh rise above a lower threshold, facilitating behaviors supported by drugs or natural reinforcers. Further increases in cholinergic tone that rise above a second upper threshold oppose the same behaviors. Accordingly, cholinesterase inhibitors, or agonists for nicotinic or muscarinic receptors, each have the potential to produce biphasic effects on reward behaviors. Pretreatment with either nicotinic or muscarinic antagonists can block drug- or food- reinforced behavior by maintaining cholinergic tone below its lower threshold. Potential threshold mediators include desensitization of nicotinic receptors and biphasic effects of ACh on the firing of medium spiny neurons. Nicotinic receptors with high- and low- affinity appear to play greater roles in reward enhancement and inhibition, respectively. Cholinergic inhibition of natural and drug rewards may serve as mediators of previously described opponent processes. Future studies should evaluate cholinergic agents across a broader range of doses, and include a variety of reinforced behaviors.
Collapse
Affiliation(s)
- Kenneth Grasing
- From the Substance Abuse Research Laboratory, 151, Kansas City Veterans Affairs Medical Center, 4801 Linwood Boulevard, Kansas City, MO 64128, United States; From the Division of Clinical Pharmacology, Department of Medicine, University of Kansas School of Medicine, Kansas City, KS 66160, United States.
| |
Collapse
|
40
|
Ovsepian SV, O'Leary VB, Zaborszky L. Cholinergic Mechanisms in the Cerebral Cortex: Beyond Synaptic Transmission. Neuroscientist 2016; 22:238-51. [PMID: 26002948 PMCID: PMC4681696 DOI: 10.1177/1073858415588264] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Functional overviews of cholinergic mechanisms in the cerebral cortex have traditionally focused on the release of acetylcholine with modulator and transmitter effects. Recently, however, data have emerged that extend the role of acetylcholine and cholinergic innervations to a range of housekeeping and metabolic functions. These include regulation of amyloid precursor protein (APP) processing with production of amyloid β (Aβ) and other APP fragments and control of the phosphorylation of microtubule-associated protein (MAP) tau. Evidence has been also presented for receptor-ligand like interactions of cholinergic receptors with soluble Aβ peptide and MAP tau, with modulator and signaling effects. Moreover, high-affinity binding of Aβ to the neurotrophin receptor p75 (p75NTR) enriched in basalo-cortical cholinergic projections has been implicated in clearance of Aβ and nucleation of amyloid plaques. Here, we critically evaluate these unorthodox cholinergic mechanisms and discuss their role in neuronal physiology and the biology of Alzheimer's disease.
Collapse
Affiliation(s)
- Saak V Ovsepian
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany Faculty of Science and Health, School of Biotechnology, Dublin City University, Dublin, Ireland
| | - Valerie B O'Leary
- Institute of Radiation Biology, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - Laszlo Zaborszky
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA
| |
Collapse
|
41
|
Role of β4* Nicotinic Acetylcholine Receptors in the Habenulo-Interpeduncular Pathway in Nicotine Reinforcement in Mice. Neuropsychopharmacology 2016; 41:1790-802. [PMID: 26585290 PMCID: PMC4869047 DOI: 10.1038/npp.2015.346] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 11/16/2015] [Accepted: 11/16/2015] [Indexed: 11/08/2022]
Abstract
Nicotine exerts its psychopharmacological effects by activating the nicotinic acetylcholine receptor (nAChR), composed of alpha and/or beta subunits, giving rise to a diverse population of receptors with a distinct pharmacology. β4-containing (β4*) nAChRs are located almost exclusively in the habenulo-interpeduncular pathway. We examined the role of β4* nAChRs in the medial habenula (MHb) and the interpeduncular nucleus (IPN) in nicotine reinforcement using behavioral, electrophysiological, and molecular techniques in transgenic mice. Nicotine intravenous self-administration (IVSA) was lower in constitutive β4 knockout (KO) mice at all doses tested (7.5, 15, 30, and 60 μg/kg/infusion) compared with wild-type (WT) mice. In vivo microdialysis showed that β4KO mice have higher extracellular dopamine (DA) levels in the nucleus accumbens than in WT mice, and exhibit a differential sensitivity to nicotine-induced DA outflow. Furthermore, electrophysiological recordings in the ventral tegmental area (VTA) demonstrated that DA neurons of β4KO mice are more sensitive to lower doses of nicotine than that of WT mice. Re-expression of β4* nAChRs in IPN neurons fully restored nicotine IVSA, and attenuated the increased sensitivity of VTA DA neurons to nicotine. These findings suggest that β4* nAChRs in the IPN have a role in maintaining nicotine IVSA.
Collapse
|
42
|
Christensen MH, Kohlmeier KA. Age-related changes in functional postsynaptic nicotinic acetylcholine receptor subunits in neurons of the laterodorsal tegmental nucleus, a nucleus important in drug addiction. Addict Biol 2016; 21:267-81. [PMID: 25363563 DOI: 10.1111/adb.12194] [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] [Indexed: 11/30/2022]
Abstract
The earlier an individual initiates cigarette smoking, the higher the likelihood of development of dependency to nicotine, the addictive ingredient in cigarettes. One possible mechanism underlying this higher addiction liability is an ontogenetically differential cellular response induced by nicotine in neurons mediating the reinforcing or euphoric effects of this drug, which could arise from age-related differences in the composition of nicotinic acetylcholine receptor (nAChR) subunits. In the current study, we examined whether the subunit composition of nAChRs differed between neurons within the laterodorsal tegmentum (LDT), a nucleus importantly involved in drug addiction associated behaviours, across two periods of ontogeny in which nicotine-mediated excitatory responses were shown to depend on age. To this end, whole-cell patch-clamp recordings in mouse brain slices from identified LDT neurons, in combination with nAChR subunit-specific receptor antagonists, were conducted. Comparison of the contribution of different nAChR subunits to acetylcholine (ACh)-induced inward currents indicated that the contributions of the β2 and/or β4 and α7 nAChR subunits alter across age. Taken together, we conclude that across a limited ontogenetic period, there is plasticity in the subunit composition of nAChRs in LDT neurons. In addition, our data indicate, for the first time, functional presence of α6 nAChR subunits in LDT neurons within the age ranges studied. Changes in subunit composition of nAChRs across ontogeny could contribute to the age-related differential excitability induced by nicotine. Differences in the subunit composition of nAChRs within the LDT would be expected to contribute to ontogenetic-dependent outflow from the LDT to target regions, which include reward-related circuitry.
Collapse
Affiliation(s)
- Mark H. Christensen
- Department of Drug design and Pharmacology; Faculty of Health Sciences; University of Copenhagen; Denmark
| | - Kristi A. Kohlmeier
- Department of Drug design and Pharmacology; Faculty of Health Sciences; University of Copenhagen; Denmark
| |
Collapse
|
43
|
Van Skike CE, Maggio SE, Reynolds AR, Casey EM, Bardo MT, Dwoskin LP, Prendergast MA, Nixon K. Critical needs in drug discovery for cessation of alcohol and nicotine polysubstance abuse. Prog Neuropsychopharmacol Biol Psychiatry 2016; 65:269-87. [PMID: 26582145 PMCID: PMC4679525 DOI: 10.1016/j.pnpbp.2015.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 11/10/2015] [Accepted: 11/11/2015] [Indexed: 01/29/2023]
Abstract
Polysubstance abuse of alcohol and nicotine has been overlooked in our understanding of the neurobiology of addiction and especially in the development of novel therapeutics for its treatment. Estimates show that as many as 92% of people with alcohol use disorders also smoke tobacco. The health risks associated with both excessive alcohol consumption and tobacco smoking create an urgent biomedical need for the discovery of effective cessation treatments, as opposed to current approaches that attempt to independently treat each abused agent. The lack of treatment approaches for alcohol and nicotine abuse/dependence mirrors a similar lack of research in the neurobiology of polysubstance abuse. This review discusses three critical needs in medications development for alcohol and nicotine co-abuse: (1) the need for a better understanding of the clinical condition (i.e. alcohol and nicotine polysubstance abuse), (2) the need to better understand how these drugs interact in order to identify new targets for therapeutic development and (3) the need for animal models that better mimic this human condition. Current and emerging treatments available for the cessation of each drug and their mechanisms of action are discussed within this context followed by what is known about the pharmacological interactions of alcohol and nicotine. Much has been and will continue to be gained from studying comorbid alcohol and nicotine exposure.
Collapse
Affiliation(s)
- C E Van Skike
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States
| | - S E Maggio
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States
| | - A R Reynolds
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States
| | - E M Casey
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States
| | - M T Bardo
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States; Center for Drug Abuse and Research Translation, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States
| | - L P Dwoskin
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States; Center for Drug Abuse and Research Translation, University of Kentucky, Lexington, KY 40536, United States
| | - M A Prendergast
- Department of Psychology, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States
| | - K Nixon
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, United States.
| |
Collapse
|
44
|
Nicotinic modulation of hippocampal cell signaling and associated effects on learning and memory. Physiol Behav 2015; 155:162-71. [PMID: 26687895 DOI: 10.1016/j.physbeh.2015.12.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 11/30/2015] [Accepted: 12/10/2015] [Indexed: 11/21/2022]
Abstract
The hippocampus is a key brain structure involved in synaptic plasticity associated with long-term declarative memory formation. Importantly, nicotine and activation of nicotinic acetylcholine receptors (nAChRs) can alter hippocampal plasticity and these changes may occur through modulation of hippocampal kinases and transcription factors. Hippocampal kinases such as cAMP-dependent protein kinase (PKA), calcium/calmodulin-dependent protein kinases (CAMKs), extracellular signal-regulated kinases 1 and 2 (ERK1/2), and c-jun N-terminal kinase 1 (JNK1), and the transcription factor cAMP-response element-binding protein (CREB) that are activated either directly or indirectly by nicotine may modulate hippocampal plasticity and in parallel hippocampus-dependent learning and memory. Evidence suggests that nicotine may alter hippocampus-dependent learning by changing the time and magnitude of activation of kinases and transcription factors normally involved in learning and by recruiting additional cell signaling molecules. Understanding how nicotine alters learning and memory will advance basic understanding of the neural substrates of learning and aid in understanding mental disorders that involve cognitive and learning deficits.
Collapse
|
45
|
Quik M, Zhang D, McGregor M, Bordia T. Alpha7 nicotinic receptors as therapeutic targets for Parkinson's disease. Biochem Pharmacol 2015; 97:399-407. [PMID: 26093062 PMCID: PMC4600450 DOI: 10.1016/j.bcp.2015.06.014] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/11/2015] [Indexed: 11/25/2022]
Abstract
Accumulating evidence suggests that CNS α7 nicotinic acetylcholine receptors (nAChRs) are important targets for the development of therapeutic approaches for Parkinson's disease. This progressive neurodegenerative disorder is characterized by debilitating motor deficits, as well as autonomic problems, cognitive declines, changes in affect and sleep disturbances. Currently l-dopa is the gold standard treatment for Parkinson's disease motor problems, particularly in the early disease stages. However, it does not improve the other symptoms, nor does it reduce the inevitable disease progression. Novel therapeutic strategies for Parkinson's disease are therefore critical. Extensive pre-clinical work using a wide variety of experimental models shows that nicotine and nAChR agonists protect against damage to nigrostriatal and other neuronal cells. This observation suggests that nicotine and/or nAChR agonists may be useful as disease modifying agents. Additionally, studies in several parkinsonian animal models including nonhuman primates show that nicotine reduces l-dopa-induced dyskinesias, a side effect of l-dopa therapy that may be as incapacitating as Parkinson's disease itself. Work with subtype selective nAChR agonists indicate that α7 nAChRs are involved in mediating both the neuroprotective and antidyskinetic effects, thus offering a targeted strategy with optimal beneficial effects and minimal adverse responses. Here, we review studies demonstrating a role for α7 nAChRs in protection against neurodegenerative effects and for the reduction of l-dopa-induced dyskinesias. Altogether, this work suggests that α7 nAChRs may be useful targets for reducing Parkinson's disease progression and for the management of the dyskinesias that arise with l-dopa therapy.
Collapse
Affiliation(s)
- Maryka Quik
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, CA 94025, USA.
| | - Danhui Zhang
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, CA 94025, USA
| | - Matthew McGregor
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, CA 94025, USA
| | - Tanuja Bordia
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, CA 94025, USA
| |
Collapse
|
46
|
Shih PY, McIntosh JM, Drenan RM. Nicotine Dependence Reveals Distinct Responses from Neurons and Their Resident Nicotinic Receptors in Medial Habenula. Mol Pharmacol 2015; 88:1035-44. [PMID: 26429939 DOI: 10.1124/mol.115.101444] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/30/2015] [Indexed: 01/22/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are the molecular target of nicotine. nAChRs in the medial habenula (MHb) have recently been shown to play a role in nicotine dependence, but it is not clear which nAChR subtypes or MHb neuron types are most important. To identify MHb nAChRs and/or cell types that play a role in nicotine dependence, we studied these receptors and cells with brain slice electrophysiology using both acute and chronic nicotine application. Cells in the ventroinferior (MHbVI) and ventrolateral MHb (MHbVL) subregions expressed functional nAChRs with different pharmacology. Further, application of nicotine to cells in these subregions led to different action potential firing patterns. The latter result was correlated with a differing ability of nicotine to induce nAChR desensitization. Chronic nicotine caused functional upregulation of nAChRs selectively in MHbVI cells, but did not change nAChR function in MHbVL. Importantly, firing responses were also differentially altered in these subregions following chronic nicotine. MHbVI neurons treated chronically with nicotine exhibited enhanced basal pacemaker firing but a blunted nicotine-induced firing response. MHbVL neurons did not change their firing properties in response to chronic nicotine. Together, these results suggest that acute and chronic nicotine differentially affect nAChR function and output of cells in MHb subregions. Because the MHb extensively innervates the interpeduncular nucleus, an area critical for both affective and somatic signs of withdrawal, these results could reflect some of the neurophysiological changes thought to occur in the MHb to the interpeduncular nucleus circuit in human smokers.
Collapse
Affiliation(s)
- Pei-Yu Shih
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (P.-Y.S., R.M.D.) and George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah (J.M.M.)
| | - J Michael McIntosh
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (P.-Y.S., R.M.D.) and George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah (J.M.M.)
| | - Ryan M Drenan
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (P.-Y.S., R.M.D.) and George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah (J.M.M.)
| |
Collapse
|
47
|
Dani JA. Neuronal Nicotinic Acetylcholine Receptor Structure and Function and Response to Nicotine. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 124:3-19. [PMID: 26472524 DOI: 10.1016/bs.irn.2015.07.001] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) belong to the "Cys-loop" superfamily of ligand-gated ion channels that includes GABAA, glycine, and serotonin (5-HT3) receptors. There are 16 homologous mammalian nAChR subunits encoded by a multigene family. These subunits combine to form many different nAChR subtypes with various expression patterns, diverse functional properties, and differing pharmacological characteristics. Because cholinergic innervation is pervasive and nAChR expression is extremely broad, practically every area of the brain is impinged upon by nicotinic mechanisms. This review briefly examines the structural and functional properties of the receptor/channel complex itself. The review also summarizes activation and desensitization of nAChRs by the low nicotine concentrations obtained from tobacco. Knowledge of the three-dimensional structure and the structural characteristics of channel gating has reached an advanced stage. Likewise, the basic functional properties of the channel also are reasonably well understood. It is these receptor/channel properties that underlie the participation of nAChRs in nearly every anatomical region of the mammalian brain.
Collapse
Affiliation(s)
- John A Dani
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| |
Collapse
|
48
|
Ton HT, Smart AE, Aguilar BL, Olson TT, Kellar KJ, Ahern GP. Menthol Enhances the Desensitization of Human α3β4 Nicotinic Acetylcholine Receptors. Mol Pharmacol 2015; 88:256-64. [PMID: 25964258 DOI: 10.1124/mol.115.098285] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/11/2015] [Indexed: 11/22/2022] Open
Abstract
The α3β4 nicotinic acetylcholine receptor (nAChR) subtype is widely expressed in the peripheral and central nervous systems, including in airway sensory nerves. The nAChR subtype transduces the irritant effects of nicotine in tobacco smoke and, in certain brain areas, may be involved in nicotine addiction and/or withdrawal. Menthol, a widely used additive in cigarettes, is a potential analgesic and/or counterirritant at sensory nerves and may also influence nicotine's actions in the brain. We examined menthol's effects on recombinant human α3β4 nAChRs and native nAChRs in mouse sensory neurons. Menthol markedly decreased nAChR activity as assessed by Ca(2+) imaging, (86)Rb(+) efflux, and voltage-clamp measurements. Coapplication of menthol with acetylcholine or nicotine increased desensitization, demonstrated by an increase in the rate and magnitude of the current decay and a reduction of the current integral. These effects increased with agonist concentration. Pretreatment with menthol followed by its washout did not affect agonist-induced desensitization, suggesting that menthol must be present during the application of agonist to augment desensitization. Notably, menthol acted in a voltage-independent manner and reduced the mean open time of single channels without affecting their conductance, arguing against a simple channel-blocking effect. Further, menthol slowed or prevented the recovery of nAChRs from desensitization, indicating that it probably stabilizes a desensitized state. Moreover, menthol at concentrations up to 1 mM did not compete for the orthosteric nAChR binding site labeled by [(3)H]epibatidine. Taken together, these data indicate that menthol promotes desensitization of α3β4 nAChRs by an allosteric action.
Collapse
Affiliation(s)
- Hoai T Ton
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Amanda E Smart
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Brittany L Aguilar
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Thao T Olson
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Kenneth J Kellar
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| | - Gerard P Ahern
- Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
| |
Collapse
|
49
|
Antidepressant-like effects of the cannabinoid receptor ligands in the forced swimming test in mice: Mechanism of action and possible interactions with cholinergic system. Behav Brain Res 2015; 284:24-36. [DOI: 10.1016/j.bbr.2015.01.051] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 01/26/2015] [Accepted: 01/30/2015] [Indexed: 12/23/2022]
|
50
|
Anderson SM, Brunzell DH. Anxiolytic-like and anxiogenic-like effects of nicotine are regulated via diverse action at β2*nicotinic acetylcholine receptors. Br J Pharmacol 2015; 172:2864-77. [PMID: 25625469 DOI: 10.1111/bph.13090] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/19/2014] [Accepted: 01/19/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Nicotine dose-dependently activates or preferentially desensitizes β2 subunit containing nicotinic ACh receptors (β2*nAChRs). Genetic and pharmacological manipulations assessed effects of stimulation versus inhibition of β2*nAChRs on nicotine-associated anxiety-like phenotype. EXPERIMENTAL APPROACH Using a range of doses of nicotine in β2*nAChR subunit null mutant mice (β2KO; backcrossed to C57BL/6J) and their wild-type (WT) littermates, administration of the selective β2*nAChR agonist, 5I-A85380, and the selective β2*nAChR antagonist dihydro-β-erythroidine (DHβE), we determined the behavioural effects of stimulation and inhibition of β2*nAChRs in the light-dark and elevated plus maze (EPM) assays. KEY RESULTS Low-dose i.p. nicotine (0.05 mg·kg(-) 1) supported anxiolysis-like behaviour independent of genotype whereas the highest dose (0.5 mg·kg(-1) ) promoted anxiogenic-like phenotype in WT mice, but was blunted in β2KO mice for the measure of latency. Administration of 5I-A85380 had similar dose-dependent effects in C57BL/6J WT mice; 0.001 mg·kg(-1) 5I-A85380 reduced anxiety on an EPM, whereas 0.032 mg·kg(-1) 5I-A85380 promoted anxiogenic-like behaviour in both the light-dark and EPM assays. DHβE pretreatment blocked anxiogenic-like effects of 0.5 mg·kg(-1) nicotine. Similarly to DHβE, pretreatment with low-dose 0.05 mg·kg(-1) nicotine did not accumulate with 0.5 mg·kg(-1) nicotine, but rather blocked anxiogenic-like effects of high-dose nicotine in the light-dark and EPM assays. CONCLUSIONS AND IMPLICATIONS These studies provide direct evidence that low-dose nicotine inhibits nAChRs and demonstrate that inhibition or stimulation of β2*nAChRs supports the corresponding anxiolytic-like or anxiogenic-like effects of nicotine. Inhibition of β2*nAChRs may relieve anxiety in smokers and non-smokers alike.
Collapse
Affiliation(s)
- S M Anderson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - D H Brunzell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| |
Collapse
|