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Havermans A, Zwart EP, Cremers HWJM, van Schijndel MDM, Constant RS, Mešković M, Worutowicz LX, Pennings JLA, Talhout R, van der Ven LTM, Heusinkveld HJ. Exploring Neurobehaviour in Zebrafish Embryos as a Screening Model for Addictiveness of Substances. TOXICS 2021; 9:toxics9100250. [PMID: 34678946 PMCID: PMC8539716 DOI: 10.3390/toxics9100250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/23/2021] [Accepted: 09/29/2021] [Indexed: 12/04/2022]
Abstract
Tobacco use is the leading cause of preventable death worldwide and is highly addictive. Nicotine is the main addictive compound in tobacco, but less is known about other components and additives that may contribute to tobacco addiction. The zebrafish embryo (ZFE) has been shown to be a good model to study the toxic effects of chemicals on the neurological system and thus may be a promising model to study behavioral markers of nicotine effects, which may be predictive for addictiveness. We aimed to develop a testing protocol to study nicotine tolerance in ZFE using a locomotion test with light-dark transitions as behavioral trigger. Behavioral experiments were conducted using three exposure paradigms: (1) Acute exposure to determine nicotine’s effect and potency. (2) Pre-treatment with nicotine dose range followed by a single dose of nicotine, to determine which pre-treatment dose is sufficient to affect the potency of acute nicotine. (3) Pre-treatment with a single dose combined with acute exposure to a dose range to confirm the hypothesized decreased potency of the acute nicotine exposure. These exposure paradigms showed that (1) acute nicotine exposure decreased ZFE activity in response to dark conditions in a dose-dependent fashion; (2) pre-treatment with increasing concentrations dose-dependently reversed the effect of acute nicotine exposure; and (3) a fixed pre-treatment dose of nicotine induced a decreased potency of the acute nicotine exposure. This effect supported the induction of tolerance to nicotine by the pre-treatment, likely through neuroadaptation. The interpretation of these effects, particularly in view of prediction of dependence and addictiveness, and suitability of the ZFE model to test for such effects of other compounds than nicotine, are discussed.
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Fartootzadeh R, Alaei H, Reisi P. Mutual assistance of nucleus accumbens cannabinoid receptor-1 and orexin receptor-2 in response to nicotine: a single-unit study. Res Pharm Sci 2021; 16:173-181. [PMID: 34084204 PMCID: PMC8102922 DOI: 10.4103/1735-5362.310524] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/22/2020] [Accepted: 01/24/2021] [Indexed: 11/28/2022] Open
Abstract
Background and purpose: The nucleus accumbens (NAc) express both orexin-2 receptor (OX2R) and cannabinoid receptor type 1 (CB1R). Orexin and cannabinoid regulate the addictive properties of nicotine. In this study, the effect of the CB1R blockade on the electrical activity of NAc neurons in response to nicotine, and its probable interaction with the OX2R in this event, within this area, were examined via the single-unit recording. Experimental approach: The spontaneous firing rate of NAc was initially recorded for 15 min, and then 5 min before subcutaneous injection of nicotine (0.5 mg/kg)/saline, AM251 and TCS-OX2-29 were injected into the NAc. Neuronal responses were recorded for 70 min, after nicotine administration. Findings/Results: Nicotine excited the NAc neurons significantly and intra-NAc microinjection of AM251 (25 and 125 ng/rat), as a selective CB1R antagonist, prevented the nicotine-induced increases of NAc neuronal responses. Moreover, microinjection of AM251 (125 ng/rat), before saline injection, could not affect the percentage of change of the neuronal response. Finally, simultaneous intra-NAc administration of the effective or ineffective doses of AM251 and TCS-OX2-29 (a selective antagonist of OX2R) prevented the nicotine- induced increases of NAc neuronal responses, so that there was a significant difference between the group received ineffective doses of both antagonists and the AM251 ineffective dose. Conclusion and implications: The results suggest that the CB1R can modulate the NAc reaction to the nicotine, and it can be concluded that there is a potential interplay between the OX2R and CB1R in the NAc, in relation to nicotine.
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Affiliation(s)
- Reza Fartootzadeh
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, I.R. Iran
| | - Hojjatallah Alaei
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, I.R. Iran
| | - Parham Reisi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, I.R. Iran
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Liachenko S, Ramu J. Sex differences in the effect of acute administration of nicotine on MRS-measured metabolic profile of the rat brain. Neurosci Res 2019; 157:51-57. [PMID: 31381938 DOI: 10.1016/j.neures.2019.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/19/2019] [Accepted: 07/30/2019] [Indexed: 10/26/2022]
Abstract
Women are less able to stop smoking than men. Elucidation of sex differences in the tobacco addiction could facilitate personalized treatment. Specialized brain reward systems are controlling the behavior through reinforcement using specific neuromediators. Using non-invasive magnetic resonance spectroscopy (MRS) to ascertain addiction/harm biomarkers could lead to better management of public health through advancements in regulatory and translational research. Proton MRS was used to monitor changes of specific neurometabolites in hippocampus (HC), nucleus accumbens (NAC), and anterior cingulate cortex (ACC) of rats of both sexes after single intraperitoneal injection of nicotine. At the baseline, male rats showed higher level of GABA, taurine, N-acetyl aspartate, and creatine in HC, and taurine in NAC. Also, there were stronger correlations between neurometabolites in females than in males at the baseline. Nicotine administration changed taurine, GABA, myo-inositol, choline, and N-acetyl aspartate in HC, and taurine in NAC. Significant interactions between time, treatment, and sex were detected for taurine and choline in HC. The number of inter-metabolite correlations increased significantly in ACC and decreased in NAC and HC in females after nicotine administration, while in males it was unchanged. There are distinct sex differences in neurometabolic profiles at the baseline and after acute nicotine administration. Nicotine changes inter-metabolite correlations in females more than in males.
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Affiliation(s)
- Serguei Liachenko
- Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR, 72079, USA.
| | - Jaivijay Ramu
- Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR, 72079, USA
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Functional crosstalk of nucleus accumbens CB1 and OX2 receptors in response to nicotine-induced place preference. Neurosci Lett 2019; 698:160-164. [PMID: 30659912 DOI: 10.1016/j.neulet.2019.01.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 12/17/2018] [Accepted: 01/15/2019] [Indexed: 01/01/2023]
Abstract
In the present study, we have evaluated the existence of functional interaction between orexin-2 receptor (OX2R) and cannabinoid-1 receptor (CB1R) in the nucleus accumbens core (NAcc), in nicotine-induced conditioned place preference (CPP) of Wistar male rat. Nicotine (0.5 mg/kg; s.c.) in the course of conditioning, produced a significant place preference, without any effect on the locomotor activity. Intra-NAcc administration of ineffective and effective doses of TCS-OX2-29 (2 and 6 ng/rat), a selective OX2R antagonist and AM251 (10 and 50 ng/rat), a selective CB1R antagonist, showed a significant interaction between OX2R and CB1R in the acquisition of nicotine-induced CPP (p < 0.01), and the locomotor activity (p < 0.05). No significant interaction was observed between these two receptors in the expression of nicotine-induced CPP. Our findings provide insight into the possible interaction of OX2R and CB1R of the NAcc in nicotine addiction. We propose a potential interaction between cannabinoid and orexinergic systems within the NAcc, in producing the rewarding effects.
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Fartootzadeh R, Azizi F, Alaei H, Reisi P. Orexin type-2 receptor blockade prevents the nicotine-induced excitation of nucleus accumbens core neurons in rats: An electrophysiological perspective. Pharmacol Rep 2019; 71:361-366. [PMID: 30831442 DOI: 10.1016/j.pharep.2018.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 12/11/2018] [Accepted: 12/29/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND The nucleus accumbens core (NAcc) expresses both orexin and nicotinic acetylcholine receptors (nAChRs). Orexin is among important neurotransmitters, which regulates addictive properties of drugs of abuse including nicotine. The role of orexin-2 receptor (OX2R) in the regulation of NAcc neural activity in response to nicotine has not yet been studied. Hence, in this study, we examined whether the OX2R antagonist (TCS-OX2-29) can adjust the effects of nicotine on electrical activity of NAcc neurons, in urethane-anesthetized rats, using the single unit recording. METHODS Neuronal firing of NAcc was recorded for 15 min, then TCS-OX2-29 (OX2R-antagonist; 1, 3 and 10 ng/rat) or DMSO were microinjected into NAcc, just 5 min before subcutaneous (sc) administration of nicotine (0.5 mg/kg) or saline. The spontaneous firing activity was recorded for 70 min, after nicotine injection. RESULTS The results demonstrated that nicotine significantly excites the NAcc neurons and interestingly, the administration of TCS-OX2-29 (3 and 10 ng/rat) into the NAcc, inhibited nicotine-induced increases of NAcc neuronal responses. Furthermore, administration of TCS-OX2-29 (10 ng/rat), just 5 min before sc administration of saline instead of nicotine, did not significantly alter the neuronal responses, compared to the saline-control group. CONCLUSION Our results showed that, although OX2R blockade alone did not affect neuronal activity in the NAcc, it was able to prevent the exciting effects of nicotine on NAcc neuronal activity. Therefore, we proposed that orexin has a potential modulator effect, in response to nicotine.
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Affiliation(s)
- Reza Fartootzadeh
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Fatemeh Azizi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hojjatallah Alaei
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Parham Reisi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
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Yi Q, Zou WJ. A novel four‑snoRNA signature for predicting the survival of patients with uveal melanoma. Mol Med Rep 2018; 19:1294-1301. [PMID: 30569172 DOI: 10.3892/mmr.2018.9766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/14/2018] [Indexed: 11/06/2022] Open
Abstract
Uveal melanoma (UM), the predominant histological subtype of intraocular malignant tumors in adults, often results in high rates of mortality; effective prognostic signatures used to predict the survival of patients with UM are limited. Small nucleolar RNAs (snoRNAs) are emerging as important regulators in the processes of carcinogenesis and tumor progression, but knowledge of their application as prognostic markers in UM is limited. In the present study, the expression profiles of snoRNAs in UM were determined; a total of 60 snoRNAs were notably associated with the overall survival of patients with UM via univariate Cox survival analysis. Subsequently, a prognostic signature based on four snoRNAs was proposed, which retained their prognostic significance determined by a multivariate Cox survival analysis. The formula is as follows: ACA17 * (‑1.602) + ACA45 * 0.803 + HBII‑276 * 0.603 + SNORD12 * 1.348. Furthermore, the results of in silico analysis indicated that perturbation of the phototransduction, GABAergic synapse and amphetamine addiction pathways may be the potential molecular mechanisms underlying the poor prognosis of patients with UM. Collectively, the present study proposed a potential prognostic signature for patients with UM and the prospective mechanisms at the genome‑wide level were determined.
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Affiliation(s)
- Qiong Yi
- Department of Ophthalmology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Wen-Jin Zou
- Department of Ophthalmology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
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Arias HR, Feuerbach D, Schmidt B, Heydenreich M, Paz C, Ortells MO. Drimane Sesquiterpenoids Noncompetitively Inhibit Human α4β2 Nicotinic Acetylcholine Receptors with Higher Potency Compared to Human α3β4 and α7 Subtypes. JOURNAL OF NATURAL PRODUCTS 2018; 81:811-817. [PMID: 29634269 DOI: 10.1021/acs.jnatprod.7b00893] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The drimane sesquiterpenoids drimenin, cinnamolide, dendocarbin A, and polygodial were purified from the Canelo tree ( Drimys winteri) and chemically characterized by spectroscopic methods. The pharmacological activity of these natural compounds were determined on hα4β2, hα3β4, and hα7 nicotinic acetylcholine receptors (AChRs) by Ca2+ influx measurements. The results established that drimane sesquiterpenoids inhibit AChRs with the following selectivity: hα4β2 > hα3β4 > hα7. In the case of hα4β2 AChRs, the following potency rank order was determined (IC50's in μM): drimenin (0.97 ± 0.35) > cinnamolide (1.57 ± 0.36) > polygodial (62.5 ± 19.9) ≫ dendocarbin A (no activity). To determine putative structural features underlying the differences in inhibitory potency at hα4β2 AChRs, additional structure-activity relationship and molecular docking experiments were performed. The Ca2+ influx and structural results supported a noncompetitive mechanism of inhibition, where drimenin interacted with luminal and nonluminal (TMD-β2 intrasubunit) sites. The structure-activity relationship results, i.e., the lower the ligand polarity, the higher the inhibitory potency, supported the nonluminal interaction. Ligand binding to both sites might inhibit the hα4β2 AChR by a cooperative mechanism, as shown experimentally ( nH > 1). Drimenin could be used as a molecular scaffold for the development of more potent inhibitors with higher selectivity for the hα4β2 AChR.
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Affiliation(s)
- Hugo R Arias
- Department of Basic Sciences , California Northstate University College of Medicine , Elkgrove , California 95757 , United States
| | - Dominik Feuerbach
- Novartis Institutes for Biomedical Research , Basel CH-4057 , Switzerland
| | - Bernd Schmidt
- Department of Chemistry , University of Potsdam , D-14469 Potsdam , Germany
| | | | - Cristian Paz
- Departamento de Química y Recursos Naturales , Universidad de La Frontera , Francisco Salazar 01145 , Temuco , Chile
| | - Marcelo O Ortells
- Facultad de Medicina , Universidad de Morón and CONICET , Morón 1708 , Argentina
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Abreu-Villaça Y, Manhães AC, Krahe TE, Filgueiras CC, Ribeiro-Carvalho A. Tobacco and alcohol use during adolescence: Interactive mechanisms in animal models. Biochem Pharmacol 2017; 144:1-17. [DOI: 10.1016/j.bcp.2017.06.113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/05/2017] [Indexed: 12/13/2022]
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Dutra‐Tavares AC, Silva JO, Nunes‐Freitas AL, Guimarães VM, Araújo UC, Conceição EP, Moura EG, Lisboa PC, Filgueiras CC, Manhães AC, Abreu‐Villaça Y, Ribeiro‐Carvalho A. Maternal undernutrition during lactation alters nicotine reward and DOPAC/dopamine ratio in cerebral cortex in adolescent mice, but does not affect nicotine‐induced nAChRs upregulation. Int J Dev Neurosci 2017; 65:45-53. [DOI: 10.1016/j.ijdevneu.2017.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/15/2017] [Accepted: 10/16/2017] [Indexed: 12/19/2022] Open
Affiliation(s)
- Ana C. Dutra‐Tavares
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Juliana O. Silva
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - André L. Nunes‐Freitas
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Vinícius M.S. Guimarães
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Ulisses C. Araújo
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Ellen P.S. Conceição
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Egberto G. Moura
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Patrícia C. Lisboa
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Cláudio C. Filgueiras
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Alex C. Manhães
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Yael Abreu‐Villaça
- Departamento de Ciências FisiológicasInstituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de JaneiroAv. Prof. Manoel de Abreu 444, 5 andar – Vila IsabelRio de JaneiroRJ20550‐170Brazil
| | - Anderson Ribeiro‐Carvalho
- Departamento de Ciências, Faculdade de Formação de Professores da Universidade do Estado do Rio de JaneiroRua Dr. Francisco Portela 1470 – PatronatoSão GonçaloRJ24435‐005Brazil
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Selectivity of coronaridine congeners at nicotinic acetylcholine receptors and inhibitory activity on mouse medial habenula. Int J Biochem Cell Biol 2017; 92:202-209. [PMID: 29042244 DOI: 10.1016/j.biocel.2017.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/06/2017] [Accepted: 10/13/2017] [Indexed: 01/13/2023]
Abstract
The inhibitory activity of coronaridine congeners on human (h) α4β2 and α7 nicotinic acetylcholine receptors (AChRs) is determined by Ca2+ influx assays, whereas their effects on neurons in the ventral inferior (VI) aspect of the mouse medial habenula (MHb) are determined by patch-clamp recordings. The Ca2+ influx results clearly establish that coronaridine congeners inhibit hα3β4 AChRs with higher selectivity compared to hα4β2 and hα7 subtypes, and with the following potency sequence, for hα4β2: (±)-18-methoxycoronaridine [(±)-18-MC]>(+)-catharanthine>(±)-18-methylaminocoronaridine [(±)-18-MAC] ∼ (±)-18-hydroxycoronaridine [(±)-18-HC]; and for hα7: (+)-catharanthine>(±)-18-MC>(±)-18-HC>(±)-18-MAC. Interestingly, the inhibitory potency of (+)-catharanthine (27±4μM) and (±)-18-MC (28±6μM) on MHb (VI) neurons was lower than that observed on hα3β4 AChRs, suggesting that these compounds inhibit a variety of endogenous α3β4* AChRs. In addition, the interaction of bupropion with (-)-ibogaine sites on hα3β4 AChRs is tested by [3H]ibogaine competition binding experiments. The results indicate that bupropion binds to ibogaine sites at desensitized hα3β4 AChRs with 2-fold higher affinity than at resting receptors, suggesting that these compounds share the same binding sites. In conclusion, coronaridine congeners inhibit hα3β4 AChRs with higher selectivity compared to other AChRs, by interacting with the bupropion (luminal) site. Coronaridine congeners also inhibit α3β4*AChRs expressed in MHb (VI) neurons, supporting the notion that these receptors are important endogenous targets for their anti-addictive activities.
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Goulding DR, White SS, McBride SJ, Fenton SE, Harry GJ. Gestational exposure to perfluorooctanoic acid (PFOA): Alterations in motor related behaviors. Neurotoxicology 2017; 58:110-119. [PMID: 27888120 PMCID: PMC5345697 DOI: 10.1016/j.neuro.2016.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/18/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
Abstract
Perfluoroalkyl and polyfluoroalkyl substances are used in commercial applications and developmental exposure has been implicated in alterations in neurobehavioral functioning. While associations between developmental perfluorooctanoic acid (PFOA) exposure and human outcomes have been inconsistent, studies in experimental animals suggest alterations in motor related behaviors. To examine a dose-response pattern of neurobehavioral effects following gestational exposure to PFOA, pregnant CD-1 mice received PFOA (0, 0.1, 0.3, 1.0mg/kg/day) via oral gavage from gestational day 1-17 and the male offspring examined. Motor activity assessments on postnatal day (PND)18, 19, and 20 indicated a shift in the developmental pattern with an elevated activity level observed in the 1.0mg/kg/day dose group on PND18. In the adult, no alterations were observed in body weights, activity levels, diurnal pattern of running wheel activity, startle response, or pre-pulse startle inhibition. In response to a subcutaneous injection of saline or nicotine (80μg/kg), all animals displayed a transient increase in activity likely associated with handling with no differences observed across dose groups. Inhibition of motor activity over 18days of 400μg/kg nicotine injection was not significantly different across dose groups. Hyperactivity induced by 2mg/kg (+)-methamphetamine hydrochloride intraperitoneal injection was significantly lower in the 1.0mg/kg/day PFOA dose group as compared to controls. Taken together, these data suggest that the effects on motor-related behaviors with gestational PFOA exposure do not mimic those reported for acute postnatal exposure. Changes were not observed at dose levels under 1.0mg/kg/day PFOA. Further examination of pathways associated with methamphetamine-induced activity is warranted.
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Affiliation(s)
- David R Goulding
- Comparative Medicine Branch, Division of Intramural Research; National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Sally S White
- Reproductive Endocrinology Group, National Toxicology Program Laboratory (NTPL), Division of the National Toxicology Program (DNTP), NIEHS, USA
| | | | - Suzanne E Fenton
- Reproductive Endocrinology Group, National Toxicology Program Laboratory (NTPL), Division of the National Toxicology Program (DNTP), NIEHS, USA
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Zuo W, Xiao C, Gao M, Hopf FW, Krnjević K, McIntosh JM, Fu R, Wu J, Bekker A, Ye JH. Nicotine regulates activity of lateral habenula neurons via presynaptic and postsynaptic mechanisms. Sci Rep 2016; 6:32937. [PMID: 27596561 PMCID: PMC5011770 DOI: 10.1038/srep32937] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/12/2016] [Indexed: 11/09/2022] Open
Abstract
There is much interest in brain regions that drive nicotine intake in smokers. Interestingly, both the rewarding and aversive effects of nicotine are probably critical for sustaining nicotine addiction. The medial and lateral habenular (LHb) nuclei play important roles in processing aversion, and recent work has focused on the critical involvement of the LHb in encoding and responding to aversive stimuli. Several neurotransmitter systems are implicated in nicotine’s actions, but very little is known about how nicotinic acetylcholine receptors (nAChRs) regulate LHb activity. Here we report in brain slices that activation of nAChRs depolarizes LHb cells and robustly increases firing, and also potentiates glutamate release in LHb. These effects were blocked by selective antagonists of α6-containing (α6*) nAChRs, and were absent in α6*-nAChR knockout mice. In addition, nicotine activates GABAergic inputs to LHb via α4β2-nAChRs, at lower concentrations but with more rapid desensitization relative to α6*-nAChRs. These results demonstrate the existence of diverse functional nAChR subtypes at presynaptic and postsynaptic sites in LHb, through which nicotine could facilitate or inhibit LHb neuronal activity and thus contribute to nicotine aversion or reward.
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Affiliation(s)
- Wanhong Zuo
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Cheng Xiao
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Ming Gao
- Divisions of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - F Woodward Hopf
- Department of Neurology, University of California at San Francisco, CA, USA
| | | | - J Michael McIntosh
- George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, UT, USA
| | - Rao Fu
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Jie Wu
- Divisions of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Alex Bekker
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Jiang-Hong Ye
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
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Condoluci A, Mazzara C, Zoccoli A, Pezzuto A, Tonini G. Impact of smoking on lung cancer treatment effectiveness: a review. Future Oncol 2016; 12:2149-61. [PMID: 27424719 DOI: 10.2217/fon-2015-0055] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tobacco smoke contains more than 4000 detectable substances, such as polycyclic aromatic hydrocarbons, nicotine, carbon monoxide and heavy metals, which are considered powerful enzymatic inducers that have notable influence on the efficacy and tolerability of many medications through complex pharmacokinetic and pharmacodynamic interactions. As a result, adjustments of drug dosages are required in smokers, both if they continue to smoke or if they quit after smoking cessation treatment. The purpose of this review is to examine the main drug interactions with tobacco smoke clinically relevant, with a closer look on patients developing oncologic diseases.
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Affiliation(s)
| | - Calogero Mazzara
- Department of Oncology, University Campus Bio-Medico of Rome, Rome, Italy
| | - Alice Zoccoli
- Department of Oncology, University Campus Bio-Medico of Rome, Rome, Italy
| | - Aldo Pezzuto
- Cardiovascular & Pulmonary Department, Sant'Andrea Hospital, Sapienza University, Rome, Italy
| | - Giuseppe Tonini
- Department of Oncology, University Campus Bio-Medico of Rome, Rome, Italy
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Antuni JD, Barnes PJ. Evaluation of Individuals at Risk for COPD: Beyond the Scope of the Global Initiative for Chronic Obstructive Lung Disease. CHRONIC OBSTRUCTIVE PULMONARY DISEASES-JOURNAL OF THE COPD FOUNDATION 2016; 3:653-667. [PMID: 28848890 DOI: 10.15326/jcopdf.3.3.2016.0129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The Global initiative for chronic Obstructive Lung Disease (GOLD) Strategy is a valuable tool for clinicians in the diagnosis and management of patients with established chronic obstructive pulmonary disease (COPD). However, there are no recommendations for the evaluation of individuals, exposed to risk factors, who are most likely to develop COPD. Consequently, it is necessary to consider all of the factors that may play a role in the pathogenesis of COPD: genetic factors, gender, socioeconomic status, disadvantageous factors in childhood, lung diseases and exposure to risk factors such as smoking, biomass fuel smoke, occupational hazards and air pollution. Along with the clinical assessment, periodic spirometry should be performed to evaluate lung function and make possible early detection of individuals who will develop the disease through the rate of forced expiratory volume in 1 second (FEV1) decline. The first spirometry, periodicity, and clinically significant decline in FEV1 will encompass the cornerstones of clinical follow up. This approach allows the implementation of important interventions in order to help individuals to cease contact with risk factors and prevent progressive respiratory impairment with the consequent deterioration of quality of life and increased morbidity and mortality.
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Affiliation(s)
- Julio D Antuni
- Corporación Médica de General San Martín, Buenos Aires, Argentina
| | - Peter J Barnes
- National Heart and Lung Institute, Royal Brompton Hospital, London, United Kingdom
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15
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Obsada N, Zalewska-Kaszubska J. Wareniklina – częściowy agonista receptorów nikotynowych w terapii zespołu uzależnienia od alkoholu. ALCOHOLISM AND DRUG ADDICTION 2016. [DOI: 10.1016/j.alkona.2016.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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16
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Neuronal Nicotinic Acetylcholine Receptor Modulators Reduce Sugar Intake. PLoS One 2016; 11:e0150270. [PMID: 27028298 PMCID: PMC4814119 DOI: 10.1371/journal.pone.0150270] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/11/2016] [Indexed: 12/21/2022] Open
Abstract
Excess sugar consumption has been shown to contribute directly to weight gain, thus contributing to the growing worldwide obesity epidemic. Interestingly, increased sugar consumption has been shown to repeatedly elevate dopamine levels in the nucleus accumbens (NAc), in the mesolimbic reward pathway of the brain similar to many drugs of abuse. We report that varenicline, an FDA-approved nicotinic acetylcholine receptor (nAChR) partial agonist that modulates dopamine in the mesolimbic reward pathway of the brain, significantly reduces sucrose consumption, especially in a long-term consumption paradigm. Similar results were observed with other nAChR drugs, namely mecamylamine and cytisine. Furthermore, we show that long-term sucrose consumption increases α4β2 * and decreases α6β2* nAChRs in the nucleus accumbens, a key brain region associated with reward. Taken together, our results suggest that nAChR drugs such as varenicline may represent a novel treatment strategy for reducing sugar consumption.
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Coronaridine congeners inhibit human α3β4 nicotinic acetylcholine receptors by interacting with luminal and non-luminal sites. Int J Biochem Cell Biol 2015; 65:81-90. [PMID: 26022277 DOI: 10.1016/j.biocel.2015.05.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/28/2015] [Accepted: 05/15/2015] [Indexed: 02/06/2023]
Abstract
To characterize the interaction of coronaridine congeners with human (h) α3β4 nicotinic acetylcholine receptors (AChRs), structural and functional approaches were used. The Ca(2+) influx results established that coronaridine congeners noncompetitively inhibit hα3β4 AChRs with the following potency (IC50's in μM) sequence: (-)-ibogamine (0.62±0.23)∼(+)-catharanthine (0.68±0.10)>(-)-ibogaine (0.95±0.10)>(±)-18-methoxycoronaridine [(±)-18-MC] (1.47±0.21)>(-)-voacangine (2.28±0.33)>(±)-18-methylaminocoronaridine (2.62±0.57 μM)∼(±)-18-hydroxycoronaridine (2.81±0.54)>(-)-noribogaine (6.82±0.78). A good linear correlation (r(2)=0.771) between the calculated IC50 values and their polar surface area was found, suggesting that this is an important structural feature for its activity. The radioligand competition results indicate that (±)-18-MC and (-)-ibogaine partially inhibit [(3)H]imipramine binding by an allosteric mechanism. Molecular docking, molecular dynamics, and in silico mutation results suggest that protonated (-)-18-MC binds to luminal [i.e., β4-Phe255 (phenylalanine/valine ring; position 13'), and α3-Leu250 and β4-Leu251 (leucine ring; position 9')], non-luminal, and intersubunit sites. The pharmacophore model suggests that nitrogens from the ibogamine core as well as methylamino, hydroxyl, and methoxyl moieties at position 18 form hydrogen bonds. Collectively our data indicate that coronaridine congeners inhibit hα3β4 AChRs by blocking the ion channel's lumen and probably by additional negative allosteric mechanisms by interacting with a series of non-luminal sites.
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18
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Lin YH, Feng CH, Wang SW, Ko PY, Lee MH, Chen YL. Determination of Nicotine in Tobacco by Chemometric Optimization and Cation-Selective Exhaustive Injection in Combination with Sweeping-Micellar Electrokinetic Chromatography. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2015; 2015:869719. [PMID: 26101695 PMCID: PMC4460933 DOI: 10.1155/2015/869719] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/17/2015] [Indexed: 06/04/2023]
Abstract
Nicotine is a potent chemical that excites the central nervous system and refreshes people. It is also physically addictive and causes dependence. To reduce the harm of tobacco products for smokers, a law was introduced that requires tobacco product containers to be marked with the amount of nicotine as well as tar. In this paper, an online stacking capillary electrophoresis (CE) method with cation-selective exhaustive injection sweeping-micellar electrokinetic chromatography (CSEI-sweeping-MEKC) is proposed for the optimized analysis of nicotine in tobacco. A higher conductivity buffer (160 mM phosphate buffer (pH 3)) zone was injected into the capillary, allowing for the analytes to be electrokinetically injected at a voltage of 15 kV for 15 min. Using 50 mM sodium dodecyl sulfate and 25% methanol in the sweeping buffer, nicotine was detected with high sensitivity. Thus, optimized conditions adapted from a chemometric approach provided a 6000-fold increase in the nicotine detection sensitivity using the CSEI-sweeping-MEKC method in comparison to normal CZE. The limits of detection were 0.5 nM for nicotine. The stacking method in combination with direct injection which matrix components would not interfere with assay performance was successfully applied to the detection of nicotine in tobacco samples.
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Affiliation(s)
- Yi-Hui Lin
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung, 40402, Taiwan
| | - Chia-Hsien Feng
- Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Shih-Wei Wang
- Department of Medicine, Mackay Medical College, Taipei 252, Taiwan
| | - Po-Yun Ko
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Ming-Hsun Lee
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Yen-Ling Chen
- Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Marine Biotechnology and Resources, College of Marine Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
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19
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Arias HR, Feuerbach D, Ortells M. Functional and structural interaction of (-)-lobeline with human α4β2 and α4β4 nicotinic acetylcholine receptor subtypes. Int J Biochem Cell Biol 2015; 64:15-24. [PMID: 25794424 DOI: 10.1016/j.biocel.2015.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/02/2015] [Accepted: 03/09/2015] [Indexed: 10/23/2022]
Abstract
To determine the pharmacologic activity of (-)-lobeline between human (h)α4β2 and hα4β4 nicotinic acetylcholine receptors (AChRs), functional and structural experiments were performed. The Ca(2+) influx results established that (-)-lobeline neither actives nor enhances the function of the studied AChR subtypes, but competitively inhibits hα4β4 AChRs with potency ∼10-fold higher than that for hα4β2 AChRs. This difference is due to a higher binding affinity for the [(3)H]cytisine sites at hα4β4 compared to hα4β2 AChRs, which, in turn, can be explained by our molecular dynamics (MD) results: (1) higher stability of (-)-lobeline and its hydrogen bonds within the α4β4 pocket compared to the α4β2 pocket, (2) (-)-lobeline promotes Loop C to cap the binding site at the α4β4 pocket, but forces Loop C to get apart from the α4β2 pocket, precluding the gating process elicited by agonists, and (3) the orientation of (-)-lobeline within the α4β4, but not the α4β2, subpocket, promoted by the t- (or t+) rotameric state of α4-Tyr98, remains unchanged during the whole MD simulation. This study gives a detailed view of the molecular and dynamics events evoked by (-)-lobeline supporting the differential binding affinity and subsequent inhibitory potency between hα4β2 and hα4β4 AChRs, and supports the possibility that the latter subtype is also involved in its activity.
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Affiliation(s)
- Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA, USA.
| | - Dominik Feuerbach
- Neuroscience Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Marcelo Ortells
- Faculty of Medicine and CONICET, University of Morón, Argentina
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20
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Arias HR, Feuerbach D, Targowska-Duda K, Kaczor AA, Poso A, Jozwiak K. Pharmacological and molecular studies on the interaction of varenicline with different nicotinic acetylcholine receptor subtypes. Potential mechanism underlying partial agonism at human α4β2 and α3β4 subtypes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:731-41. [PMID: 25475645 DOI: 10.1016/j.bbamem.2014.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/29/2014] [Accepted: 11/06/2014] [Indexed: 02/06/2023]
Abstract
To determine the structural components underlying differences in affinity, potency, and selectivity of varenicline for several human (h) nicotinic acetylcholine receptors (nAChRs), functional and structural experiments were performed. The Ca2+ influx results established that: (a) varenicline activates (μM range) nAChR subtypes with the following rank sequence: hα7>hα4β4>hα4β2>hα3β4>>>hα1β1γδ; (b) varenicline binds to nAChR subtypes with the following affinity order (nM range): hα4β2~hα4β4>hα3β4>hα7>>>Torpedo α1β1γδ. The molecular docking results indicating that more hydrogen bond interactions are apparent for α4-containing nAChRs in comparison to other nAChRs may explain the observed higher affinity; and that (c) varenicline is a full agonist at hα7 (101%) and hα4β4 (93%), and a partial agonist at hα4β2 (20%) and hα3β4 (45%), relative to (±)-epibatidine. The allosteric sites found at the extracellular domain (EXD) of hα3β4 and hα4β2 nAChRs could explain the partial agonistic activity of varenicline on these nAChR subtypes. Molecular dynamics simulations show that the interaction of varenicline to each allosteric site decreases the capping of Loop C at the hα4β2 nAChR, suggesting that these allosteric interactions limit the initial step in the gating process. In conclusion, we propose that in addition to hα4β2 nAChRs, hα4β4 nAChRs can be considered as potential targets for the clinical activity of varenicline, and that the allosteric interactions at the hα3β4- and hα4β2-EXDs are alternative mechanisms underlying partial agonism at these nAChRs.
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Affiliation(s)
- Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA, USA.
| | - Dominik Feuerbach
- Neuroscience Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Katarzyna Targowska-Duda
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, Lublin, Poland
| | - Agnieszka A Kaczor
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Medical University of Lublin, Lublin, Poland
| | - Antti Poso
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Krzysztof Jozwiak
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, Lublin, Poland
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21
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Falasca S, Ranc V, Petruzziello F, Khani A, Kretz R, Zhang X, Rainer G. Altered neurochemical levels in the rat brain following chronic nicotine treatment. J Chem Neuroanat 2014; 59-60:29-35. [PMID: 24915436 DOI: 10.1016/j.jchemneu.2014.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 05/21/2014] [Accepted: 05/25/2014] [Indexed: 12/31/2022]
Abstract
Converging evidence shows that neurochemical systems are crucial mediators of nicotine dependence. Our present study evaluates the effect of 3-month chronic nicotine treatment on the levels of multiple quaternary ammonium compounds as well as glutamate and gamma aminobutyric acid in the rat prefrontal cortex, dorsal striatum and hypothalamus. We observed a marked decrease of acetylcholine levels in the dorsal striatum (22.88%, p<0.01), reflecting the impact of chronic nicotine in local interneuron circuits. We found decreases of carnitine in the dorsal striatum and prefrontal cortex (19.44%, p<0.01; 13.58%, p<0.01, respectively), but robust enhancements of carnitine in the hypothalamus (26.59%, p<0.01), which may reflect the alterations in food and water intake during chronic nicotine treatment. Finally, we identified an increase of prefrontal cortex glutamate levels (8.05%, p<0.05), supporting previous studies suggesting enhanced prefrontal activity during chronic drug use. Our study shows that quaternary ammonium compounds are regulated in a highly brain region specific manner during chronic nicotine treatment, and provides novel insights into neurochemical regulation during nicotine use.
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Affiliation(s)
- Sara Falasca
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musee 5, Fribourg CH-1700, Switzerland
| | - Vaclav Ranc
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musee 5, Fribourg CH-1700, Switzerland
| | - Filomena Petruzziello
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musee 5, Fribourg CH-1700, Switzerland
| | - Abbas Khani
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musee 5, Fribourg CH-1700, Switzerland
| | - Robert Kretz
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musee 5, Fribourg CH-1700, Switzerland
| | - Xiaozhe Zhang
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musee 5, Fribourg CH-1700, Switzerland.
| | - Gregor Rainer
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musee 5, Fribourg CH-1700, Switzerland; Fribourg Center for Cognition, University of Fribourg, Fribourg CH-1700, Switzerland
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22
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Targowska-Duda KM, Feuerbach D, Biala G, Jozwiak K, Arias HR. Antidepressant activity in mice elicited by 3-furan-2-yl-N-p-tolyl-acrylamide, a positive allosteric modulator of the α7 nicotinic acetylcholine receptor. Neurosci Lett 2014; 569:126-30. [PMID: 24708923 DOI: 10.1016/j.neulet.2014.03.067] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/19/2014] [Accepted: 03/27/2014] [Indexed: 01/05/2023]
Abstract
The objective of the current study is to determine whether 3-furan-2-yl-N-p-tolyl-acrylamide (PAM-2), a positive allosteric modulator of α7 nicotinic receptors (AChRs), produces antidepressant-like behavior in mice, and reactivates desensitized α7 AChRs expressed in CH3-α7 cells. Mice from both sexes were injected (i.p.) with PAM-2 (1.0mg/kg) on a daily basis for three weeks. Forced swim tests (FSTs) were performed on Day 1 and Day 7 to determine the acute and subchronic effects of PAM-2, respectively, and on Days 14 and 21 to determine its chronic activity. To examine the residual effects after drug treatment, a withdrawal period of two more weeks was continued with FSTs performed on Day 28 and 35. Our results indicate that: (1) PAM-2 does not induce acute antidepressant effects in male or female mice, (2) PAM-2 induces antidepressant effects in mice from both sexes after one (subchronic) and two (chronic) weeks, whereas at the third week (chronic), the antidepressant effect is decreased in male and increased in female mice. Since PAM-2 does not influence the locomotor activity of mice, the observed antidepressant activity is not driven by nonspecific motor-stimulant actions, (3) the residual antidepressant effect mediated by PAM-2 after one week of treatment cessation is observed only in female mice, and finally the Ca(2+) influx results indicate that (4) PAM-2 can reactivate desensitized α7 AChRs. Our results clearly indicate that PAM-2 elicits antidepressant activity, probably by enhancing the activity of the endogenous neurotransmitter acetylcholine on α7 AChRs, without inducing receptor desensitization, and that this activity is gender-dependent. This is the first time that an antidepressant activity is described for an α7 PAM, supporting further studies as potential therapeutic medications for depressive states.
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Affiliation(s)
- Katarzyna M Targowska-Duda
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, 4a Chodzki Street, 20-093 Lublin, Poland.
| | | | - Grazyna Biala
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, 4a Chodzki Street, 20-093 Lublin, Poland
| | - Krzysztof Jozwiak
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, 4a Chodzki Street, 20-093 Lublin, Poland
| | - Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, 9700 West Taron Drive, Elk Grove, CA 95757, USA.
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Intra-subunit flexibility underlies activation and allosteric modulation of neuronal nicotinic acetylcholine receptors. Neuropharmacology 2013; 79:420-31. [PMID: 24373904 DOI: 10.1016/j.neuropharm.2013.12.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/12/2013] [Accepted: 12/14/2013] [Indexed: 01/20/2023]
Abstract
Allosteric modulation is a general feature of nicotinic acetylcholine receptors, yet the structural components and movements important for conversions among functional states are not well understood. In this study, we examine the communication between the binding sites for agonist and the modulator morantel (Mor) of neuronal α3β2 receptors, measuring evoked currents of receptors expressed in Xenopus oocytes with the two-electrode voltage-clamp method. We hypothesized that movement along an interface of β sheets connecting the agonist and modulator sites is necessary for allosteric modulation. To address this, we created pairs of substituted cysteines that span the cleft formed where the outer β sheet meets the β sheet constituting the (-)-face of the α3 subunit; the three pairs were L158C-A179C, L158C-G181C and L158C-K183C. Employing a disulfide trapping approach in which bonds are formed between neighboring cysteines under oxidation conditions, we found that oxidation treatments decreased the amplitude of currents evoked by either the agonist (ACh) or co-applied agonist and modulator (ACh + Mor), by as much as 51%, consistent with the introduced bond decreasing channel efficacy. Reduction treatment increased evoked currents up to 89%. The magnitude of the oxidation effects depended on whether agonists were present during oxidation and on the cysteine pair. Additionally, the cysteine mutations themselves decreased Mor potentiation, implicating these residues in modulation. Our findings suggest that these β sheets in the α3 subunit move with respect to each other during activation and modulation, and the residues studied highlight the contribution of this intramolecular allosteric pathway to receptor function.
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24
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Howell MJ, Schenck CH. Restless nocturnal eating: a common feature of Willis-Ekbom Syndrome (RLS). J Clin Sleep Med 2012; 8:413-9. [PMID: 22893772 DOI: 10.5664/jcsm.2036] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
STUDY OBJECTIVES To determine the frequency of nocturnal eating (NE) and sleep related eating disorder (SRED) in restless legs syndrome (RLS) versus psychophysiological insomnia (INS), and the relationship of these conditions with dopaminergic and sedative-hypnotic medications. DESIGN Prospective case series. SETTING Sleep disorders center. PATIENTS Newly diagnosed RLS or INS. INTERVENTION RLS or INS pharmacotherapy with systematic follow up interview for NE/SRED. MEASUREMENTS AND RESULTS Patients presenting with RLS (n = 88) or INS (n = 42) were queried for the presence of NE and SRED. RLS patients described nocturnal eating (61%) and SRED (36%) more frequently than INS patients (12% and 0%; both p < 0.0001). These findings were not due to arousal frequency, as INS patients were more likely to have prolonged nightly awakenings (93%) than RLS patients (64%; p = 0.003). Among patients on sedative-hypnotics, amnestic SRED and sleepwalking were more common in the setting of RLS (80%) than INS (8%; p < 0.0001). Further, NE and SRED in RLS were not secondary to dopaminergic therapy, as RLS patients demonstrated a substantial drop (68% to 34%; p = 0.0026) in the frequency of NE after dopamine agents were initiated, and there were no cases of dopaminergic agents inducing novel NE or SRED. CONCLUSION NE is common in RLS and not due to frequent nocturnal awakenings or dopaminergic agents. Amnestic SRED occurs predominantly in the setting of RLS mistreatment with sedating agents. In light of previous reports, these findings suggest that nocturnal eating is a non-motor manifestation of RLS with several clinical implications discussed here.
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Affiliation(s)
- Michael J Howell
- Department of Neurology, Minnesota Regional Sleep Disorders Center and University of Minnesota Medical Center Sleep Disorders Center, University of Minnesota, Minneapolis, MN 55414, USA.
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25
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Chi F, Wang L, Zheng X, Jong A, Huang SH. Recruitment of α7 nicotinic acetylcholine receptor to caveolin-1-enriched lipid rafts is required for nicotine-enhanced Escherichia coli K1 entry into brain endothelial cells. Future Microbiol 2011; 6:953-66. [PMID: 21861625 DOI: 10.2217/fmb.11.65] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM We investigate how the α7 nicotinic acetylcholine receptor (α7 nAChR), an essential regulator of inflammation, contributes to the α7 agonist nicotine-enhanced Escherichia coli K1 invasion of human brain microvascular endothelial cells (HBMECs) through lipid rafts/caveolae-mediated signaling. MATERIALS & METHODS α7 nAChR-mediated signaling and bacterial invasion were defined by lipid raft fractionation, immunofluorescence microscopy and siRNA knockdown. RESULTS Nicotine-enhanced bacterial invasion was dose-dependently inhibited by two raft-disrupting agents, nystatin and filipin. Significant accumulation of the lipid raft marker GM3 was observed in HBMEC induced by E. coli K1 and nicotine. The recruitment of α7 nAChR and related signaling molecules, including vimentin, and Erk1/2, to caveolin-1 enriched lipid rafts was increased upon treatment with E44 or E44 plus nicotine. Erk1/2 activation (phosphorylation), which is required for α7 nAChR-mediated signaling and E44 invasion, was associated with lipid rafts and nicotine-enhanced bacterial infection. Furthermore, E44 invasion, E44/nicotine-induced activation of Erk1/2 and clustering of α7 nAChR and caveolin-1 was specifically blocked by both siRNAs. CONCLUSION α7 nAChR-mediated signaling through lipid rafts/caveolae is required for nicotine-enhanced E. coli K1 invasion of HBMEC.
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Affiliation(s)
- Feng Chi
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, USA
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26
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Huang LZ, Grady SR, Quik M. Nicotine reduces L-DOPA-induced dyskinesias by acting at beta2* nicotinic receptors. J Pharmacol Exp Ther 2011; 338:932-41. [PMID: 21665941 PMCID: PMC3164339 DOI: 10.1124/jpet.111.182949] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 06/09/2011] [Indexed: 12/24/2022] Open
Abstract
L-DOPA-induced dyskinesias or abnormal involuntary movements (AIMs) are a debilitating adverse complication associated with prolonged L-DOPA administration for Parkinson's disease. Few treatments are currently available for dyskinesias. Our recent data showed that nicotine reduced L-DOPA-induced AIMs in parkinsonian animal models. An important question is the nicotinic acetylcholine receptor (nAChR) subtypes through which nicotine exerts this beneficial effect, because such knowledge would allow for the development of drugs that target the relevant receptor population(s). To address this, we used β2 nAChR subunit knockout [β2(-/-)] mice because β2-containing nAChRs are key regulators of nigrostriatal dopaminergic function. All of the mice were lesioned by intracranial injection of 6-hydroxydopamine into the right medial forebrain bundle. Lesioning resulted in a similar degree of nigrostriatal damage and parkinsonism in β2(-/-) and wild-type mice. All of the mice then were injected with L-DOPA (3 mg/kg) plus benserazide (15 mg/kg) once daily for 4 weeks until AIMs were fully developed. L-DOPA-induced AIMs were approximately 40% less in the β2(-/-) mice compared with the wild-type mice. It is interesting to note that nicotine (300 μg/ml in drinking water) reduced L-DOPA-induced AIMs by 40% in wild-type mice but had no effect in β2(-/-) mice with partial nigrostriatal damage. The nicotine-mediated decline in AIMs was much less pronounced in wild-type mice with near-complete degeneration, suggesting that presynaptic nAChRs on dopaminergic terminals have a major influence. These data demonstrate an essential role for β2* nAChRs in the antidyskinetic effect of nicotine and suggest that drugs targeting these subtypes may be useful for the management of L-DOPA-induced dyskinesias in Parkinson's disease.
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Affiliation(s)
- Luping Z Huang
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, Menlo Park, California 94025, USA
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Arias HR, Feuerbach D, Targowska-Duda KM, Jozwiak K. Structure-activity relationship of ibogaine analogs interacting with nicotinic acetylcholine receptors in different conformational states. Int J Biochem Cell Biol 2011; 43:1330-9. [PMID: 21642011 DOI: 10.1016/j.biocel.2011.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 05/11/2011] [Accepted: 05/18/2011] [Indexed: 11/26/2022]
Abstract
The interaction of ibogaine analogs with nicotinic acetylcholine receptors (AChRs) in different conformational states was studied by functional and structural approaches. The results established that ibogaine analogs: (a) inhibit (±)-epibatidine-induced Ca²⁺ influx in human embryonic muscle AChRs with the following potency sequence (IC(50) in μM): (±)-18-methylaminocoronaridine (5.9±0.3)∼(±)-18-methoxycoronaridine (18-MC) (6.8±0.8)>(-)-ibogaine (17±3)∼(+)-catharanthine (20±1)>(±)-albifloranine (46±13), (b) bind to the [³H]TCP binding site with higher affinity when the Torpedo AChR is in the desensitized state compared to that in the resting state. Similar results were obtained using [³H]18-MC. These and docking results suggest a steric interaction between TCP and ibogaine analogs for the same site, (c) enhance [³H]cytisine binding to resting but not to desensitized AChRs, with desensitizing potencies (apparent EC₅₀) that correlate very well with the pK(i) values in the desensitized state, and (d) there are good bilinear correlations between the ligand molecular volumes and their affinities in the desensitized and resting states, with an optimal volume of ∼345 ų for the ibogaine site. These results indicate that the size of the binding sites for ibogaine analogs, located between the serine and nonpolar rings and shared with TCP, is an important structural feature for binding and for inducing desensitization.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, College of Pharmacy, Midwestern University, 19555 N. 59th Ave., Glendale, AZ 85308, USA.
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Arias HR, Gu RX, Feuerbach D, Guo BB, Ye Y, Wei DQ. Novel positive allosteric modulators of the human α7 nicotinic acetylcholine receptor. Biochemistry 2011; 50:5263-78. [PMID: 21510634 DOI: 10.1021/bi102001m] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The pharmacological activity of a series of novel amide derivatives was characterized on several nicotinic acetylcholine receptors (AChRs). Ca(2+) influx results indicate that these compounds are not agonists of the human (h) α4β2, α3β4, α7, and α1β1γδ AChRs; compounds 2-4 are specific positive allosteric modulators (PAMs) of hα7 AChRs, whereas compounds 1-4, 7, and 12 are noncompetitive antagonists of the other AChRs. Radioligand binding results indicate that PAMs do not inhibit binding of [(3)H]methyllycaconitine but enhance binding of [(3)H]epibatidine to hα7 AChRs, indicating that these compounds do not directly, but allosterically, interact with the hα7 agonist sites. Additional competition binding results indicate that the antagonistic action mediated by these compounds is produced by direct interaction with neither the phencyclidine site in the Torpedo AChR ion channel nor the imipramine and the agonist sites in the hα4β2 and hα3β4 AChRs. Molecular dynamics and docking results suggest that the binding site for compounds 2-4 is mainly located in the inner β-sheet of the hα7-α7 interface, ∼12 Å from the agonist locus. Hydrogen bond interactions between the amide group of the PAMs and the hα7 AChR binding site are found to be critical for their activity. The dual PAM and antagonistic activities elicited by compounds 2-4 might be therapeutically important.
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Affiliation(s)
- Hugo R Arias
- College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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Arias HR. Positive and negative modulation of nicotinic receptors. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2010; 80:153-203. [PMID: 21109220 DOI: 10.1016/b978-0-12-381264-3.00005-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nicotinic acetylcholine receptors (AChRs) are one of the best characterized ion channels from the Cys-loop receptor superfamily. The study of acetylcholine binding proteins and prokaryotic ion channels from different species has been paramount for the understanding of the structure-function relationship of the Cys-loop receptor superfamily. AChR function can be modulated by different ligand types. The neurotransmitter ACh and other agonists trigger conformational changes in the receptor, finally opening the intrinsic cation channel. The so-called gating process couples ligand binding, located at the extracellular portion, to the opening of the ion channel, located at the transmembrane region. After agonist activation, in the prolonged presence of agonists, the AChR becomes desensitized. Competitive antagonists overlap the agonist-binding sites inhibiting the pharmacological action of agonists. Positive allosteric modulators (PAMs) do not bind to the orthostetic binding sites but allosterically enhance the activity elicited by agonists by increasing the gating process (type I) and/or by decreasing desensitization (type II). Instead, negative allosteric modulators (NAMs) produce the opposite effects. Interestingly, this negative effect is similar to that found for another class of allosteric drugs, that is, noncompetitive antagonists (NCAs). However, the main difference between both categories of drugs is based on their distinct binding site locations. Although both NAMs and NCAs do not bind to the agonist sites, NACs bind to sites located in the ion channel, whereas NAMs bind to nonluminal sites. However, this classification is less clear for NAMs interacting at the extracellular-transmembrane interface where the ion channel mouth might be involved. Interestingly, PAMs and NAMs might be developed as potential medications for the treatment of several diseases involving AChRs, including dementia-, skin-, and immunological-related diseases, drug addiction, and cancer. More exciting is the potential combination of specific agonists with specific PAMs. However, we are still in the beginning of understanding how these compounds act and how these drugs can be used therapeutically.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmaceutical Sciences, Midwestern University, Glendale, AZ, USA
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