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Kalappa BI, Sun F, Johnson SR, Jin K, Uteshev VV. A positive allosteric modulator of α7 nAChRs augments neuroprotective effects of endogenous nicotinic agonists in cerebral ischaemia. Br J Pharmacol 2014; 169:1862-78. [PMID: 23713819 DOI: 10.1111/bph.12247] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 05/08/2013] [Accepted: 05/16/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Activation of α7 nicotinic acetylcholine receptors (nAChRs) can be neuroprotective. However, endogenous choline and ACh have not been regarded as potent neuroprotective agents because physiological levels of choline/ACh do not produce neuroprotective levels of α7 activation. This limitation may be overcome by the use of type-II positive allosteric modulators (PAMs-II) of α7 nAChRs, such as 1-(5-chloro-2,4-dimethoxyphenyl)-3-(5-methylisoxazol-3-yl)-urea (PNU-120596). This proof-of-concept study presents a novel neuroprotective paradigm that converts endogenous choline/ACh into potent neuroprotective agents in cerebral ischaemia by inhibiting α7 nAChR desensitization using PNU-120596. EXPERIMENTAL APPROACH An electrophysiological ex vivo cell injury assay (to quantify the susceptibility of hippocampal neurons to acute injury by complete oxygen and glucose deprivation; COGD) and an in vivo middle cerebral artery occlusion model of ischaemia were used in rats. KEY RESULTS Choline (20-200 μM) in the presence, but not absence of 1 μM PNU-120596 significantly delayed anoxic depolarization/injury of hippocampal CA1 pyramidal neurons, but not CA1 stratum radiatum interneurons, subjected to COGD in acute hippocampal slices and these effects were blocked by 20 nM methyllycaconitine, a selective α7 antagonist, thus, activation of α7 nAChRs was required. PNU-120596 alone was ineffective ex vivo. In in vivo experiments, both pre- and post-ischaemia treatments with PNU-120596 (30 mg·kg(-1) , s.c. and 1 mg·kg(-1) , i.v., respectively) significantly reduced the cortical/subcortical infarct volume caused by transient focal cerebral ischaemia. PNU-120596 (1 mg·kg(-1) , i.v., 30 min post-ischaemia) remained neuroprotective in rats subjected to a choline-deficient diet for 14 days prior to experiments. CONCLUSIONS AND IMPLICATIONS PNU-120596 and possibly other PAMs-II significantly improved neuronal survival in cerebral ischaemia by augmenting neuroprotective effects of endogenous choline/ACh.
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Affiliation(s)
- Bopanna I Kalappa
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
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Thiriez C, Villafane G, Grapin F, Fenelon G, Remy P, Cesaro P. Can nicotine be used medicinally in Parkinson’s disease? Expert Rev Clin Pharmacol 2014; 4:429-36. [DOI: 10.1586/ecp.11.27] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Discriminative-stimulus effects of NS9283, a nicotinic α4β2* positive allosteric modulator, in nicotine-discriminating rats. Psychopharmacology (Berl) 2014; 231:67-74. [PMID: 23925734 DOI: 10.1007/s00213-013-3207-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 07/04/2013] [Indexed: 02/02/2023]
Abstract
RATIONALE Neuronal α4β2* nicotinic acetylcholine receptors mediate cognition, pain, and the discriminative and reinforcing effects of nicotine. In addition to traditional orthosteric agonists, α4β2* positive allosteric modulators (PAMs) have recently been identified. With increased subtype selectivity relative to agonists, PAMs administered alone or in combination with low-dose α4β2* agonists may be used as powerful tools for increasing our understanding of α4β2* pharmacology. OBJECTIVES The present experiments tested the nicotine discriminative-stimulus effects of the α4β2* PAM NS9283 (A-969933) in the presence and absence of low-dose nicotine or nicotinic subtype-selective agonist. METHODS Rats were trained to discriminate 0.4 mg/kg nicotine from saline in a two-lever drug discrimination paradigm. In subsequent generalization tests, rats were administered nicotine, the α4β2*-preferring agonist ABT-594, and NS9283, alone or in two-drug combinations. RESULTS Nicotine and ABT-594 showed dose-dependent nicotine generalization. NS9283 alone resulted in a non-significant increase in nicotine-appropriate lever selection. Combination of non-effective doses of nicotine or ABT-594 with escalating doses of NS9283 resulted in a complete conversion to 100 % nicotine-appropriate choice in the case of nicotine combination and incomplete, though significant, generalization for ABT-594. CONCLUSIONS The α4β2* PAM NS9283 alone did not produce nicotine-like discriminative effects, but did demonstrate dose-related increases in nicotine lever choice when combined with a non-effective dose of nicotine or the α4β2* agonist ABT-594. This finding provides confirmation of the positive allosteric modulating effect of NS9283 in a functional in vivo paradigm. NS9283 is a potentially valuable tool for studying the role of α4β2* receptors in various nicotinic acetylcholine receptor-related functions.
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Kucinski A, Wersinger S, Stachowiak EK, Corso TD, Parry MJ, Zhang J, Jordan K, Letchworth S, Bencherif M, Stachowiak MK. Neuronal nicotinic receptor agonists ameliorate spontaneous motor asymmetries and motor discoordination in a unilateral mouse model of Parkinson's disease. Pharmacol Biochem Behav 2013; 111:1-10. [DOI: 10.1016/j.pbb.2013.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 06/21/2013] [Accepted: 07/03/2013] [Indexed: 12/24/2022]
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Chambers RP, Call GB, Meyer D, Smith J, Techau JA, Pearman K, Buhlman LM. Nicotine increases lifespan and rescues olfactory and motor deficits in a Drosophila model of Parkinson's disease. Behav Brain Res 2013; 253:95-102. [DOI: 10.1016/j.bbr.2013.07.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 07/08/2013] [Accepted: 07/12/2013] [Indexed: 11/28/2022]
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Dexter DT, Jenner P. Parkinson disease: from pathology to molecular disease mechanisms. Free Radic Biol Med 2013; 62:132-144. [PMID: 23380027 DOI: 10.1016/j.freeradbiomed.2013.01.018] [Citation(s) in RCA: 469] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 12/21/2022]
Abstract
Parkinson disease (PD) is a complex neurodegenerative disorder with both motor and nonmotor symptoms owing to a spreading process of neuronal loss in the brain. At present, only symptomatic treatment exists and nothing can be done to halt the degenerative process, as its cause remains unclear. Risk factors such as aging, genetic susceptibility, and environmental factors all play a role in the onset of the pathogenic process but how these interlink to cause neuronal loss is not known. There have been major advances in the understanding of mechanisms that contribute to nigral dopaminergic cell death, including mitochondrial dysfunction, oxidative stress, altered protein handling, and inflammation. However, it is not known if the same processes are responsible for neuronal loss in nondopaminergic brain regions. Many of the known mechanisms of cell death are mirrored in toxin-based models of PD, but neuronal loss is rapid and not progressive and limited to dopaminergic cells, and drugs that protect against toxin-induced cell death have not translated into neuroprotective therapies in humans. Gene mutations identified in rare familial forms of PD encode proteins whose functions overlap widely with the known molecular pathways in sporadic disease and these have again expanded our knowledge of the neurodegenerative process but again have so far failed to yield effective models of sporadic disease when translated into animals. We seem to be missing some key parts of the jigsaw, the trigger event starting many years earlier in the disease process, and what we are looking at now is merely part of a downstream process that is the end stage of neuronal death.
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Affiliation(s)
- David T Dexter
- Parkinson's Disease Research Group, Centre for Neuroinflammation & Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Peter Jenner
- Neurodegenerative Diseases Research Group, Institute of Pharmaceutical Science, School of Biomedical Sciences, King's College London, London SE1 9NH, UK.
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Sun F, Jin K, Uteshev VV. A type-II positive allosteric modulator of α7 nAChRs reduces brain injury and improves neurological function after focal cerebral ischemia in rats. PLoS One 2013; 8:e73581. [PMID: 23951360 PMCID: PMC3739732 DOI: 10.1371/journal.pone.0073581] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/26/2013] [Indexed: 11/19/2022] Open
Abstract
In the absence of clinically-efficacious therapies for ischemic stroke there is a critical need for development of new therapeutic concepts and approaches for prevention of brain injury secondary to cerebral ischemia. This study tests the hypothesis that administration of PNU-120596, a type-II positive allosteric modulator (PAM-II) of α7 nicotinic acetylcholine receptors (nAChRs), as long as 6 hours after the onset of focal cerebral ischemia significantly reduces brain injury and neurological deficits in an animal model of ischemic stroke. Focal cerebral ischemia was induced by a transient (90 min) middle cerebral artery occlusion (MCAO). Animals were then subdivided into two groups and injected intravenously (i.v.) 6 hours post-MCAO with either 1 mg/kg PNU-120596 (treated group) or vehicle only (untreated group). Measurements of cerebral infarct volumes and neurological behavioral tests were performed 24 hrs post-MCAO. PNU-120596 significantly reduced cerebral infarct volume and improved neurological function as evidenced by the results of Bederson, rolling cylinder and ladder rung walking tests. These results forecast a high therapeutic potential for PAMs-II as effective recruiters and activators of endogenous α7 nAChR-dependent cholinergic pathways to reduce brain injury and improve neurological function after cerebral ischemic stroke.
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Affiliation(s)
- Fen Sun
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, Fort Worth, TX, United States of America
| | - Kunlin Jin
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, Fort Worth, TX, United States of America
| | - Victor V. Uteshev
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, Fort Worth, TX, United States of America
- * E-mail:
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Kasture S, Mohan M, Kasture V. Mucuna pruriens seeds in treatment of Parkinson’s disease: pharmacological review. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s13596-013-0126-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Cytochrome P450 enzymes (CYPs) metabolize many drugs that act on the central nervous system (CNS), such as antidepressants and antipsychotics; drugs of abuse; endogenous neurochemicals, such as serotonin and dopamine; neurotoxins; and carcinogens. This takes place primarily in the liver, but metabolism can also occur in extrahepatic organs, including the brain. This is important for CNS-acting drugs, as variation in brain CYP-mediated metabolism may be a contributing factor when plasma levels do not predict drug response. This review summarizes the characterization of CYPs in the brain, using examples from the CYP2 subfamily, and discusses sources of variation in brain CYP levels and metabolism. Some recent experiments are described that demonstrate how changes in brain CYP metabolism can influence drug response, toxicity and drug-induced behaviours. Advancing knowledge of brain CYP-mediated metabolism may help us understand why patients respond differently to drugs used in psychiatry and predict risk for psychiatric disorders, including neurodegenerative diseases and substance abuse.
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Affiliation(s)
| | - Rachel F. Tyndale
- Correspondence to: R.F. Tyndale, Department of Pharmacology and Toxicology, 1 King’s College Circle, Toronto ON M5S 1A8;
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Lortet S, Lacombe E, Boulanger N, Rihet P, Nguyen C, Kerkerian-Le Goff L, Salin P. Striatal molecular signature of subchronic subthalamic nucleus high frequency stimulation in parkinsonian rat. PLoS One 2013; 8:e60447. [PMID: 23593219 PMCID: PMC3617149 DOI: 10.1371/journal.pone.0060447] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 02/26/2013] [Indexed: 11/19/2022] Open
Abstract
This study addresses the molecular mechanisms underlying the action of subthalamic nucleus high frequency stimulation (STN-HFS) in the treatment of Parkinson's disease and its interaction with levodopa (L-DOPA), focusing on the striatum. Striatal gene expression profile was assessed in rats with nigral dopamine neuron lesion, either treated or not, using agilent microarrays and qPCR verification. The treatments consisted in anti-akinetic STN-HFS (5 days), chronic L-DOPA treatment inducing dyskinesia (LIDs) or the combination of the two treatments that exacerbated LIDs. STN-HFS modulated 71 striatal genes. The main biological processes associated with the differentially expressed gene products include regulation of growth, of apoptosis and of synaptic transmission, and extracellular region is a major cellular component implicated. In particular, several of these genes have been shown to support survival or differentiation of striatal or of dopaminergic neurons. These results indicate that STN HFS may induce widespread anatomo-functional rearrangements in the striatum and create a molecular environment favorable for neuroprotection and neuroplasticity. STN-HFS and L-DOPA treatment share very few common gene regulation features indicating that the molecular substrates underlying their striatal action are mostly different; among the common effects is the down-regulation of Adrb1, which encodes the adrenergic beta-1-receptor, supporting a major role of this receptor in Parkinson's disease. In addition to genes already reported to be associated with LIDs (preprodynorphin, thyrotropin-releasing hormone, metabotropic glutamate receptor 4, cannabinoid receptor 1), the comparison between DOPA and DOPA/HFS identifies immunity-related genes as potential players in L-DOPA side effects.
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Affiliation(s)
- Sylviane Lortet
- Aix-Marseille Université, CNRS, IBDM UMR 7288, Marseille, France.
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Fan ZK, Cao Y, Lv G, Wang YS, Guo ZP. The effect of cigarette smoke exposure on spinal cord injury in rats. J Neurotrauma 2013; 30:473-9. [PMID: 23234244 DOI: 10.1089/neu.2012.2574] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In this study, we examined whether cigarette smoke has neuroprotective or toxic effects on spinal cord injury (SCI). Male Sprague-Dawley rats were included in the study and received either cigarette smoke exposure or fresh air exposure. Twenty-four hours after the last cigarette smoke or fresh air exposure, all rats were injured at thoracic level 12 (T12), using an established static compression model. Our data showed that the cigarette smoke group had higher water content; higher permeability of the blood-spinal cord barrier (BSCB); higher malondialdehyde (MDA) levels, aquaporin-4 (AQP4) and hypoxia-inducible factor 1-alpha (HIF-1α) protein expression, and mRNA levels; and lower glutathione (GSH) levels than the control group values at 12 h, 24 h, and 48 h after SCI. There was no significant difference in these between the cigarette smoke group and the control group at 0 h after SCI. The results of the Basso, Beattie, and Bresnahan (BBB) hindlimb locomotor rating scale showed that rats in the cigarette smoke group had greater dysfunction in hindlimb movement than did rats in control group from 2 to day 6 after SCI. The extent of recovery did not make any difference from day 7 to day 10 after SCI between the cigarette smoke group and the control group. These results suggested that cigarette smoke can reinforce the oxidative stress injury via HIF-1α and AQP4 in the early stage after SCI. It is possible that cigarette smoke exposure does not affect SCI recovery in the long term; however, it can aggravate the edema and deteriorate BSCB disruption via HIF-1α and AQP4 in the early stage after SCI. More studies will be essential to consider this hypothesis and elucidate the mechanisms involved.
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Affiliation(s)
- Zhong-kai Fan
- Department of Orthopaedics, The First Affiliated Hospital, Liaoning Medical University, Jinzhou, Liaoning Province, China.
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Naddafi F, Reza Haidari M, Azizi G, Sedaghat R, Mirshafiey A. Novel therapeutic approach by nicotine in experimental model of multiple sclerosis. INNOVATIONS IN CLINICAL NEUROSCIENCE 2013; 10:20-25. [PMID: 23696955 PMCID: PMC3659034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
BACKGROUND Multiple sclerosis is an autoimmune, neurodegenerative disease of the central nervous system. The cause of multiple sclerosis is still unknown, and there is no cure for multiple sclerosis. Experimental autoimmune encephalomyelitis is considered as an animal model for multiple sclerosis. The therapeutic role of nicotine has been proven to be effective in both Alzheimer's and Parkinson's disease, thus we examined, for the first time, the role of nicotine in the experimental autoimmune encephalomyelitis model. METHODS Experimental autoimmune encephalomyelitis induction was performed according to Guang-Xian Zhang et al. Treatment with nicotine was started on Day 7 post-immunization. Prevention with nicotine was started on Day 7 pre-immunization. Also for in-vitro analysis, we used U-87 MG cell line to evaluate the inhibitory effect of nicotine in cell proliferation, pro-inflammatory cytokines (TNF-alpha, IL-lbeta, IL-6) and MMP-2 activity by MTT, ELISA, and zymoanalysis methods, respectively. Moreover, the brains of mice were removed for histological analysis. RESULTS Our findings showed that treatment with nicotine caused a significant reduction in the severity and onset of the experimental autoimmune encephalomyelitis. Histological analysis indicated that there was very mild and mild plaque in the brain sections of nicotine prevention and treatment groups, respectively. CONCLUSION Our data indicate that nicotine can significantly improve the clinical score and attenuate the demyelinating pathology typically found in experimental autoimmune encephalomyelitis, indicating that nicotine has protective effects in experimental model of multiple sclerosis.
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Affiliation(s)
- Fatemeh Naddafi
- Ms. Naddafi is from Department of Cellular and Molecular Biology, Kish International Campus, University of Tehran, Tehran, Iran; Dr. Haidari is from Department of Neurology, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran; Mr. Azizi is from Imam Hassan Mojtaba Hospital, Alborz University of Medical Sciences, Kara], Iran; Dr. Sedaghat is from Department of Anatomy and Pathology, Faculty of Medicine, Shahed University, Tehran, Iran; and Dr. Mirshafiey is from Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Hurley LL, Tizabi Y. Neuroinflammation, neurodegeneration, and depression. Neurotox Res 2013; 23:131-44. [PMID: 22895696 PMCID: PMC3751583 DOI: 10.1007/s12640-012-9348-1] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/26/2012] [Accepted: 07/30/2012] [Indexed: 12/19/2022]
Abstract
Neurodegeneration and depression are two common co-morbid conditions, particularly within the aging population. Research has linked neuroinflammation as a major contributing factor to both of these diseases. The key to neuroinflammation effects on neurodegeneration and depression appears to lie within the dysregulation of the control and release of pro- and anti-inflammatory cytokines. This can come from an internal or external insult to the system, or from changes in the individual due to aging that culminate in immune dysregulation. The need to reduce neuroinflammation has led to extensive research into neuroprotectants. We discuss the efficacy found with nicotine, alcohol, resveratrol, curcumin, and ketamine. Our main focus will be on what research tells us about the connections between neuroinflammation, neurodegeneration, and depression, and the hope that neuroprotectants research gives people suffering from neurodegeneration and depression stemming from neuroinflammation. We will conclude by making suggestions for future research in this area.
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Affiliation(s)
- Laura L. Hurley
- Department of Pharmacology, College of Medicine, Howard University, Washington, DC 20059
| | - Yousef Tizabi
- Department of Pharmacology, College of Medicine, Howard University, Washington, DC 20059
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Talka R, Salminen O, Whiteaker P, Lukas RJ, Tuominen RK. Nicotine–morphine interactions at α4β2, α7 and α3⁎ nicotinic acetylcholine receptors. Eur J Pharmacol 2013; 701:57-64. [DOI: 10.1016/j.ejphar.2013.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/19/2012] [Accepted: 01/09/2013] [Indexed: 12/12/2022]
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Abstract
Many scientific journals, government agencies, and universities require disclosure of sources of funding and financial interests related to research, such as stock ownership, consulting arrangements with companies, and patents. Although disclosure has become one of the central approaches for responding to financial conflicts of interest (COIs) in research, critics contend that information about financial COIs does not serve as a reliable indicator of research credibility, and therefore, studies should be evaluated solely based on their scientific merits. We argue that, while it is indeed important to evaluate studies on their scientific merits, it is often difficult to detect significant influences of financial relationships that affect research credibility. Moreover, at least five factors can be examined to determine whether financial relationships are likely to enhance, undermine, or have no impact on the credibility of research. These include as follows: whether sponsors, institutions, or researchers have a significant financial stake in the outcome of a study; whether the financial interests of the sponsors, institutions, or researchers coincide with the goal of conducting research that is objective and reliable; whether the sponsor, institution, or researchers have a history of biasing research in order to promote their financial goals; how easy it is to manipulate the research in order to achieve financial goals; and whether oversight mechanisms are in place which are designed to minimize bias. Since these factors vary from case to case, evaluating the impact of financial relationships depends on the circumstances. In some situations, one may decide that the financial relationships significantly undermine the study's credibility; in others, one may decide that they have no impact on credibility or even enhance it.
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Affiliation(s)
- David B Resnik
- National Institute for Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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Nicotinic acetylcholine receptors: From basic science to therapeutics. Pharmacol Ther 2013; 137:22-54. [DOI: 10.1016/j.pharmthera.2012.08.012] [Citation(s) in RCA: 382] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 08/20/2012] [Indexed: 12/14/2022]
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Chen X, Wu G, Schwarzschild MA. Urate in Parkinson's disease: more than a biomarker? Curr Neurol Neurosci Rep 2012; 12:367-75. [PMID: 22580741 DOI: 10.1007/s11910-012-0282-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disease with characteristic motor manifestations. Although appreciation of PD as a multisystem disorder has grown, loss of dopaminergic neurons in the substantia nigra remains a pathological and neurochemical hallmark, accounting for the substantial symptomatic benefits of dopamine replacement therapies. However, currently no treatment has been shown to prevent or forestall the progression of the disease in spite of tremendous efforts. Among multiple environmental and genetic factors that have been implicated in the pathogenesis of PD, oxidative stress is proposed to play a critical role. A recent confluence of clinical, epidemiological, and laboratory evidence identified urate, an antioxidant and end product of purine metabolism, as not only a molecular predictor for both reduced risk and favorable progression of PD but also a potential neuroprotectant for the treatment of PD. This review summarizes recent findings on urate in PD and their clinical implications.
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Affiliation(s)
- Xiqun Chen
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Charlestown, MA 02129, USA.
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Breining SR, Melvin M, Bhatti BS, Byrd GD, Kiser MN, Hepler CD, Hooker DN, Zhang J, Reynolds LA, Benson LR, Fedorov NB, Sidach SS, Mitchener JP, Lucero LM, Lukas RJ, Whiteaker P, Yohannes D. Structure-activity studies of 7-heteroaryl-3-azabicyclo[3.3.1]non-6-enes: a novel class of highly potent nicotinic receptor ligands. J Med Chem 2012; 55:9929-45. [PMID: 23025891 DOI: 10.1021/jm3011299] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The potential for nicotinic ligands with affinity for the α4β2 or α7 subtypes to treat such diverse diseases as nicotine addiction, neuropathic pain, and neurodegenerative and cognitive disorders has been exhibited clinically for several compounds while preclinical activity in relevant in vivo models has been demonstrated for many more. For several therapeutic programs, we sought nicotinic ligands with various combinations of affinity and function across both subtypes, with an emphasis on dual α4β2-α7 ligands, to explore the possibility of synergistic effects. We report here the structure-activity relationships (SAR) for a novel series of 7-heteroaryl-3-azabicyclo[3.3.1]non-6-enes and characterize many of the analogues for activity at multiple nicotinic subtypes.
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Affiliation(s)
- Scott R Breining
- Targacept, Inc. 200 East First Street, Suite 300, Winston-Salem, North Carolina 27101, USA.
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Hijioka M, Matsushita H, Ishibashi H, Hisatsune A, Isohama Y, Katsuki H. α7 Nicotinic acetylcholine receptor agonist attenuates neuropathological changes associated with intracerebral hemorrhage in mice. Neuroscience 2012; 222:10-9. [DOI: 10.1016/j.neuroscience.2012.07.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 06/26/2012] [Accepted: 07/11/2012] [Indexed: 10/28/2022]
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Cannon JR, Greenamyre JT. Gene-environment interactions in Parkinson's disease: specific evidence in humans and mammalian models. Neurobiol Dis 2012; 57:38-46. [PMID: 22776331 DOI: 10.1016/j.nbd.2012.06.025] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/08/2012] [Accepted: 06/25/2012] [Indexed: 12/21/2022] Open
Abstract
Interactions between genetic factors and environmental exposures are thought to be major contributors to the etiology of Parkinson's disease. While such interactions are poorly defined and incompletely understood, recent epidemiological studies have identified specific interactions of potential importance to human PD. In this review, the most current data on gene-environment interactions in PD from human studies are critically discussed. Animal models have also highlighted the importance of genetic susceptibility to toxicant exposure and data of potential relevance to human PD are discussed. Goals and needs for the future of the field are proposed.
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Affiliation(s)
- Jason R Cannon
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA.
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Quik M, Wonnacott S. α6β2* and α4β2* nicotinic acetylcholine receptors as drug targets for Parkinson's disease. Pharmacol Rev 2012; 63:938-66. [PMID: 21969327 DOI: 10.1124/pr.110.003269] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Parkinson's disease is a debilitating movement disorder characterized by a generalized dysfunction of the nervous system, with a particularly prominent decline in the nigrostriatal dopaminergic pathway. Although there is currently no cure, drugs targeting the dopaminergic system provide major symptomatic relief. As well, agents directed to other neurotransmitter systems are of therapeutic benefit. Such drugs may act by directly improving functional deficits in these other systems, or they may restore aberrant motor activity that arises as a result of a dopaminergic imbalance. Recent research attention has focused on a role for drugs targeting the nicotinic cholinergic systems. The rationale for such work stems from basic research findings that there is an extensive overlap in the organization and function of the nicotinic cholinergic and dopaminergic systems in the basal ganglia. In addition, nicotinic acetylcholine receptor (nAChR) drugs could have clinical potential for Parkinson's disease. Evidence for this proposition stems from studies with experimental animal models showing that nicotine protects against neurotoxin-induced nigrostriatal damage and improves motor complications associated with l-DOPA, the "gold standard" for Parkinson's disease treatment. Nicotine interacts with multiple central nervous system receptors to generate therapeutic responses but also produces side effects. It is important therefore to identify the nAChR subtypes most beneficial for treating Parkinson's disease. Here we review nAChRs with particular emphasis on the subtypes that contribute to basal ganglia function. Accumulating evidence suggests that drugs targeting α6β2* and α4β2* nAChR may prove useful in the management of Parkinson's disease.
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Affiliation(s)
- Maryka Quik
- Center for Health Sciences, SRI International, Menlo Park, CA 94025, USA.
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73
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Quik M, Perez XA, Bordia T. Nicotine as a potential neuroprotective agent for Parkinson's disease. Mov Disord 2012. [PMID: 22693036 DOI: 10.1002/mds.v27.810.1002/mds.25028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023] Open
Abstract
Converging research efforts suggest that nicotine and other drugs that act at nicotinic acetylcholine receptors (nAChRs) may be beneficial in the management of Parkinson's disease. This idea initially stemmed from the results of epidemiological studies that demonstrated that smoking is associated with a decreased incidence of Parkinson's disease. The subsequent finding that nicotine administration protected against nigrostriatal damage in parkinsonian animal models led to the idea that nicotine in tobacco products may contribute to this apparent protective action. Nicotine most likely exerts its effects by interacting at nAChRs. Accumulating research indicates that multiple subtypes containing nAChRs, including α4β2, α6β2, and/or α7, may be involved. Stimulation of nAChRs initially activates various intracellular transduction pathways primarily via alterations in calcium signaling. Consequent adaptations in immune responsiveness and trophic factors may ultimately mediate nicotine's ability to reduce/halt the neuronal damage that arises in Parkinson's disease. In addition to a potential neuroprotective action, nicotine also has antidepressant properties and improves attention/cognition. Altogether, these findings suggest that nicotine and nAChR drugs represent promising therapeutic agents for the management of Parkinson's disease.
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Affiliation(s)
- Maryka Quik
- Center for Health Sciences, SRI International, Menlo Park, California, USA.
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74
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Das D, Cherbuin N, Anstey KJ, Sachdev PS, Easteal S. Lifetime cigarette smoking is associated with striatal volume measures. Addict Biol 2012; 17:817-25. [PMID: 21392170 DOI: 10.1111/j.1369-1600.2010.00301.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nicotine, the primary addictive component of tobacco, affects the mammalian brain. Smokers' brains have smaller cortical grey matter volumes and/or lower densities compared with non-smokers'. Differences in subcortical structures like the striatum are however, less clear. A high concentration of nicotinic receptors makes the striatum a potential target for nicotine. In addition, striatal nuclei are essential components of the reward/reinforcement pathway involved in addiction. The aim of this study was to explore the relationship between striatal nuclei (caudate, putamen and nucleus accumbens area) volumes and lifetime smoking in a large community-based sample of 'young-old' individuals. Brain volumes were measured using a semi-automated method in 315 participants aged 64-70 years who were selected from a larger randomly sampled cohort and who consented to a magnetic resonance imaging scan. Multiple regression analysis was used to assess the relationship between striatal volumes and cigarette smoking measures while controlling for age, sex, intracranial and total brain volumes and general physical and mental health measures. Greater lifetime use of cigarettes (measured in pack-years) was associated with smaller left nucleus accumbens area volume (P = 0.018) and larger left putamen volume (P = 0.025). Greater putaminal volume was also associated with a lower age at smoking initiation (P = 0.004). In this generally healthy cohort, lifetime use of cigarettes is significantly associated with striatal volume measures. These changes could indicate predisposing factors for nicotine addiction, or an effect of chronic nicotine exposure or a combination of both.
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Affiliation(s)
- Debjani Das
- John Curtin School of Medical Research, The Australian National University, Australia.
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75
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Quik M, Perez XA, Bordia T. Nicotine as a potential neuroprotective agent for Parkinson's disease. Mov Disord 2012; 27:947-57. [PMID: 22693036 DOI: 10.1002/mds.25028] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 03/13/2012] [Accepted: 04/08/2012] [Indexed: 02/06/2023] Open
Abstract
Converging research efforts suggest that nicotine and other drugs that act at nicotinic acetylcholine receptors (nAChRs) may be beneficial in the management of Parkinson's disease. This idea initially stemmed from the results of epidemiological studies that demonstrated that smoking is associated with a decreased incidence of Parkinson's disease. The subsequent finding that nicotine administration protected against nigrostriatal damage in parkinsonian animal models led to the idea that nicotine in tobacco products may contribute to this apparent protective action. Nicotine most likely exerts its effects by interacting at nAChRs. Accumulating research indicates that multiple subtypes containing nAChRs, including α4β2, α6β2, and/or α7, may be involved. Stimulation of nAChRs initially activates various intracellular transduction pathways primarily via alterations in calcium signaling. Consequent adaptations in immune responsiveness and trophic factors may ultimately mediate nicotine's ability to reduce/halt the neuronal damage that arises in Parkinson's disease. In addition to a potential neuroprotective action, nicotine also has antidepressant properties and improves attention/cognition. Altogether, these findings suggest that nicotine and nAChR drugs represent promising therapeutic agents for the management of Parkinson's disease.
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Affiliation(s)
- Maryka Quik
- Center for Health Sciences, SRI International, Menlo Park, California, USA.
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76
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Nielsen HH, Qiu J, Friis S, Wermuth L, Ritz B. Treatment for Helicobacter pylori infection and risk of Parkinson's disease in Denmark. Eur J Neurol 2012; 19:864-9. [PMID: 22248366 PMCID: PMC3330170 DOI: 10.1111/j.1468-1331.2011.03643.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND PURPOSE It has been speculated that gastrointestinal infection with Helicobacter pylori (HP) contributes to the development of Parkinson's disease (PD). We used nationwide Danish registers to investigate this hypothesis. METHODS We identified 4484 patients with a first time PD diagnosis between 2001 and 2008 from the Danish National Patient Register (DNPR) and 22, 416 population controls from the Danish Civil Registration System (CRS). Information on drug use was obtained from the National Prescription Registry (NPR). We used logistic regression to compute odds ratios (OR) for the association between treatment for HP and risk of PD. RESULTS Prescriptions for HP-eradication drugs and proton pump inhibitors (PPI) 5 or more years prior to the diagnosis of PD were associated with a 45% and 23% increase in PD risk, respectively. Hospitalizations and outpatient visits for gastritis and peptic/duodenal ulcers, however, were not associated with PD. CONCLUSIONS Our population-based study suggests that chronic HP infections and/or gastritis contribute to PD or that these are PD-related pathologies that precede motor symptoms.
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Affiliation(s)
- H H Nielsen
- Department of Neurology, Odense University Hospital, Odense, Denmark.
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77
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Positive allosteric modulation of α4β2 nAChR agonist induced behaviour. Brain Res 2012; 1458:67-75. [PMID: 22552114 DOI: 10.1016/j.brainres.2012.03.064] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/05/2012] [Accepted: 03/28/2012] [Indexed: 11/22/2022]
Abstract
Neuronal cholinergic transmission is a prerequisite for proper CNS function. Consequently, disturbance of this system is associated with a number of pathophysiological conditions such as Parkinson's disease, Alzheimer's disease, schizophrenia and ADHD. Consequently, drug discovery efforts have spurred considerable research endeavours into identifying specific compounds for this system. Nicotinic acetylcholine receptors (nAChR) are ligand gated ion channels involved in cholinergic transmission. nAChRs are homo- or heteromeric pentamers with α4β2 receptors being the most abundant heteromer. The stoichiometry of α4β2 receptors can be either (α4)(3)(β2)(2) or (α4)(2)(β2)(3) representing channels with low (LS) or high (HS) sensitivity, respectively, to endogenous ligands. In the present study we applied the partial nAChR α4β2 LS and HS agonist NS3956 and the LS selective positive allosteric modulator NS9283 to investigate the role of α4β2 in Parkinson and pain models. In 6-OHDA lesioned rats, NS3956 increased rotational behaviour when rats were co-treated with nomifensine. This effect was absent in the presence of mecamylamine. In contrast, co-treatment with NS3956 and NS9283 reduced rotational behaviour in the animals. In a rat formalin pain model NS3956 induced an analgesic response that was strongly potentiated by NS9283. Finally in vitro experiments were applied to determine dopamine release from striatal minces. NS3956 induced a concentration dependent release while NS9283 was unable to potentiate agonist induced release. Together these results emphasize involvement of α4β2 nAChR in rotational and analgesic responses and confirm striatal α4β2 receptors to be of the HS form.
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78
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Kucinski A, Wersinger S, Stachowiak EK, Radell M, Hesse R, Corso T, Parry M, Bencherif M, Jordan K, Letchworth S, Stachowiak MK. Unilateral 6-OHDA <i>th-fgfr1</i>(<i>tk-</i>) mouse model supports the role of FGFs in Parkinson’s disease and the effects of nicotine and L-DOPA on spontaneous motor impairments. Health (London) 2012. [DOI: 10.4236/health.2012.431176] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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79
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Searles Nielsen S, Gallagher LG, Lundin JI, Longstreth WT, Smith-Weller T, Franklin GM, Swanson PD, Checkoway H. Environmental tobacco smoke and Parkinson's disease. Mov Disord 2011; 27:293-6. [PMID: 22095755 DOI: 10.1002/mds.24012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 08/30/2011] [Accepted: 09/26/2011] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Parkinson's disease is inversely associated with cigarette smoking, but its relation with passive smoking or environmental tobacco smoke exposure is rarely examined. METHODS Within a case-control study, we assessed the association between Parkinson's disease and living or working with active smokers. Cases were newly diagnosed with idiopathic Parkinson's disease (n = 154) from western Washington State in 2002-2008. Age- and sex-matched controls (n = 173) were neurologically normal and unrelated to cases. RESULTS Compared with never active or passive tobacco smokers, we observed reduced Parkinson's disease risks for ever passive only smokers (OR, 0.34; 95% CI, 0.16-0.73), similar to those for ever active smokers (OR, 0.35; 95% CI, 0.17-0.73). Among persons whose only tobacco smoke exposure was passive smoking at home, risk was inversely associated with years exposed. CONCLUSIONS These observations parallel those well established for active smoking. However, it remains unresolved whether a true protective effect of tobacco smoke, generally detrimental to health, underlies these associations.
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Affiliation(s)
- Susan Searles Nielsen
- University of Washington, Department of Environmental and Occupational Health Sciences, Seattle, Washington 98195-7234, USA.
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80
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Kroker KS, Rast G, Rosenbrock H. Differential effects of subtype-specific nicotinic acetylcholine receptor agonists on early and late hippocampal LTP. Eur J Pharmacol 2011; 671:26-32. [PMID: 21968142 DOI: 10.1016/j.ejphar.2011.09.167] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 09/13/2011] [Accepted: 09/15/2011] [Indexed: 01/14/2023]
Abstract
Brain nicotinic acetylcholine receptors are involved in several neuropsychiatric disorders, e.g. Alzheimer's and Parkinson's diseases, Tourette's syndrome, schizophrenia, depression, autism, attention deficit hyperactivity disorder, and anxiety. Currently, approaches selectively targeting the activation of specific nicotinic acetylcholine receptors are in clinical development for treatment of memory impairment of Alzheimer's disease patients. These are α4β2 and α7 nicotinic acetylcholine receptor agonists which are believed to enhance cholinergic and glutamatergic neurotransmission, respectively. In order to gain a better insight into the mechanistic role of these two nicotinic acetylcholine receptors in learning and memory, we investigated the effects of the α4β2 nicotinic acetylcholine receptor agonist TC-1827 and the α7 nicotinic acetylcholine receptor partial agonist SSR180711 on hippocampal long-term potentiation (LTP), a widely accepted cellular experimental model of memory formation. Generally, LTP is distinguished in an early and a late form, the former being protein-synthesis independent and the latter being protein-synthesis dependent. TC-1827 was found to increase early LTP in a bell-shaped dose dependent manner, but did not affect late LTP. In contrast, the α7 nicotinic acetylcholine receptor partial agonist SSR180711 showed enhancing effects on both early and late LTP in a bell-shaped manner. Furthermore, SSR180711 not only increased early LTP, but also transformed it into late LTP, which was not observed with the α4β2 nicotinic acetylcholine receptor agonist. Therefore, based on these findings α7 nicotinic acetylcholine receptor (partial) agonists appear to exhibit stronger efficacy on memory improvement than α4β2 nicotinic acetylcholine receptor agonists.
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Affiliation(s)
- Katja S Kroker
- Boehringer Ingelheim Pharma GmbH & Co KG, Department of CNS Diseases Research, Birkendorfer Strasse 65, 88397 Biberach, Germany.
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81
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Vieira-Brock PL, Miller EI, Nielsen SM, Fleckenstein AE, Wilkins DG. Simultaneous quantification of nicotine and metabolites in rat brain by liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2011; 879:3465-74. [PMID: 21963483 DOI: 10.1016/j.jchromb.2011.09.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 09/09/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
Abstract
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous quantification of nicotine (NIC), cotinine (COT), nornicotine (NNIC), norcotinine (NCOT), nicotine-N-β-D-glucuronide (NIC GLUC), cotinine-N-β-D-glucuronide (COT GLUC), nicotine-1'-oxide (NNO), cotinine-N-oxide (CNO), trans-3'-hydroxycotinine (3-HC), anabasine (AB) and anatabine (AT) was modified and validated for quantification of these selected analytes in rat brain tissue. This analytical method provides support for preclinical NIC pharmacokinetic and toxicological studies after controlled dosing protocols. After brain homogenization and solid-phase extraction, target analytes and corresponding deuterated internal standards were chromatographically separated on a Discovery(®) HS F5 HPLC column with gradient elution and analyzed by LC-MS/MS in positive electrospray ionization (ESI) mode with multiple reaction monitoring (MRM) data acquisition. Method linearity was assessed and calibration curves were determined over the following ranges: 0.1-7.5 ng/mg for NIC, COT GLUC and AB; and 0.025-7.5 ng/mg for COT, NNIC, NCOT, NIC GLUC, NNO, CNO, 3-HC and AT (R(2)≥0.99 for all analytes). Extraction recoveries ranged from 64% to 115%, LC-MS/MS matrix effects were ≤21%, and overall process efficiency ranged from 57% to 93% at low and high quality control concentrations. Intra- and inter-assay imprecisions and accuracy for all analytes were ≤12.9% and ≥86%, respectively. The method was successfully applied to quantification of NIC and metabolites in the brain of post-natal day 90 rats that were sacrificed 2-h after a single 0.8 mg/kg s.c. administration of (-)NIC. In these tissues, striatal concentrations were 204.8±49.4, 138.2±14.2 and 36.1±6.1 pg/mg of NIC, COT and NNIC, respectively. Concentrations of NIC, COT and NNIC in the remaining whole brain (RWhB) were 183.3±68.0, 130.0±14.1 and 46.7±10.3 pg/mg, respectively. Quantification of these same analytes in plasma was also performed by a previously validated method. NIC, COT, NNIC, NCOT, NNO and CNO were detected in plasma with concentrations comparable to those reported in previous studies. However, and in contrast to brain tissues, COT concentrations in plasma were significantly higher than were those of NIC (194.6±18.6 ng/mL versus 52.7±12.9 ng/mL). Taken together, these results demonstrate that a sensitive and selective method has been developed for the determination of NIC biomarkers in rat brain.
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Affiliation(s)
- Paula L Vieira-Brock
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, United States.
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82
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Effects of lipid-analog detergent solubilization on the functionality and lipidic cubic phase mobility of the Torpedo californica nicotinic acetylcholine receptor. J Membr Biol 2011; 243:47-58. [PMID: 21922299 DOI: 10.1007/s00232-011-9392-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/26/2011] [Indexed: 01/08/2023]
Abstract
Over the past three decades, the Torpedo californica nicotinic acetylcholine receptor (nAChR) has been one of the most extensively studied membrane protein systems. However, the effects of detergent solubilization on nAChR stability and function are poorly understood. The use of lipid-analog detergents for nAChR solubilization has been shown to preserve receptor stability and functionality. The present study used lipid-analog detergents from phospholipid-analog and cholesterol-analog detergent families for solubilization and affinity purification of the receptor and probed nAChR ion channel function using planar lipid bilayers (PLBs) and stability using analytical size exclusion chromatography (A-SEC) in the detergent-solubilized state. We also examined receptor mobility on the lipidic cubic phase (LCP) by measuring the nAChR mobile fraction and diffusion coefficient through fluorescence recovery after photobleaching (FRAP) experiments using lipid-analog and non-lipid-analog detergents. Our results show that it is possible to isolate stable and functional nAChRs using lipid-analog detergents, with characteristic ion channel currents in PLBs and minimal aggregation as observed in A-SEC. Furthermore, fractional mobility and diffusion coefficient values observed in FRAP experiments were similar to the values observed for these parameters in the recently LCP-crystallized β(2)-adrenergic receptor. The overall results show that phospholipid-analog detergents with 16 carbon acyl-chains support nAChR stability, functionality and LCP mobility.
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83
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Gottwald MD, Aminoff MJ. Therapies for dopaminergic-induced dyskinesias in parkinson disease. Ann Neurol 2011; 69:919-27. [DOI: 10.1002/ana.22423] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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84
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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 DOI: 10.1124/jpet.111.182949] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [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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85
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Hijioka M, Matsushita H, Hisatsune A, Isohama Y, Katsuki H. Therapeutic Effect of Nicotine in a Mouse Model of Intracerebral Hemorrhage. J Pharmacol Exp Ther 2011; 338:741-9. [DOI: 10.1124/jpet.111.182519] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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86
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Hu J, Zhu C, Liu Y, Wang F, Huang Z, Fan W, Wu J. Dynamic alterations of gene expression of nicotinic acetylcholine receptor α7, α4 and β2 subunits in an acute MPTP-lesioned mouse model. Neurosci Lett 2011; 494:232-6. [PMID: 21406211 DOI: 10.1016/j.neulet.2011.03.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/25/2011] [Accepted: 03/08/2011] [Indexed: 01/07/2023]
Abstract
Epidemiologic studies show that the prevalence of Parkinson's disease (PD) is lower in smokers than in nonsmokers. Nicotine, a potent agonist of nicotinic acetylcholine receptors (nAChRs), excites midbrain dopaminergic neurons and this may contribute to the anti-parkinsonian effects. However, the alterations in gene expression of nAChR subunits using an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse PD model remain unclear. In the present study, we profile the time course of nAChR α7, α4 and β2 subunit expression levels using a comparative RT-PCR approach after acute MPTP injection. The results fall into four categories. (1) MPTP treatment transiently increased nAChR α7 (after last injection of MPTP 3 and 24 h), α4 and β2 (24 h) mRNA expression in the substantia nigra (SN) and striatum. (2) Compared to cortical and hippocampal tissues, this transient increase of nAChR subunit expression specifically occurred in the SN and striatum. (3) In the acute MPTP model, time-courses of altered expression for nAChR α7, α4 and β2 subunits closely mirrored the deficits observed in animal motor activity. (4) Stereological data showed that after administration of MPTP for 24h, there was a robust astrogliosis in the SN associated with significant dopaminergic neurodegeneration. These changes followed or paralleled MPTP-induced elevation in the levels of α7, α4 and β2 mRNAs. Collectively, our results demonstrate that nAChRs are important targets in the MPTP neurotoxic process. These data suggest that therapeutic strategies targeted toward nAChR α7, α4 and β2 subunits may have potential for developing new treatments for PD.
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Affiliation(s)
- Jun Hu
- Department of Orthopedics, the First Affiliated Hospital of Nanjing Medical University, Guang Zhou Road 300, Nanjing 210029, China
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87
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Huang LZ, Campos C, Ly J, Ivy Carroll F, Quik M. Nicotinic receptor agonists decrease L-dopa-induced dyskinesias most effectively in partially lesioned parkinsonian rats. Neuropharmacology 2011; 60:861-8. [PMID: 21232546 DOI: 10.1016/j.neuropharm.2010.12.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 11/28/2022]
Abstract
L-dopa therapy for Parkinson's disease leads to dyskinesias or abnormal involuntary movement (AIMs) for which there are few treatment options. Our previous data showed that nicotine administration reduced L-dopa-induced AIMs in parkinsonian monkeys and rats. To further understand how nicotine mediates its antidyskinetic action, we investigated the effect of nicotinic receptor (nAChR) agonists in unilateral 6-OHDA-lesioned rats with varying striatal damage. We first tested the drugs in L-dopa-treated rats with a near-complete striatal dopamine lesion (>99%), the standard rodent dyskinesia model. Varenicline, an agonist that interacts with multiple nAChRs, did not significantly reduce L-dopa-induced AIMs, while 5-iodo-A-85380 (A-85380), which acts selectively at α4β2* and α6β2* subtypes, reduced AIMs by 20%. By contrast, both varenicline and A-85380 reduced L-dopa-induced AIMs by 40-50% in rats with a partial striatal dopamine lesion. Neither drug worsened the antiparkinsonian action of L-dopa. The results show that selective nicotinic agonists reduce dyskinesias, and that they are optimally effective in animals with partial striatal dopamine damage. These findings suggest that presynaptic dopamine terminal α4β2* and α6β2* nAChRs are critical for nicotine's antidyskinetic action. The current data have important implications for the use of nicotinic receptor-directed drugs for L-dopa-induced dyskinesias, a debilitating motor complication of dopamine replacement therapy for Parkinson's disease.
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Affiliation(s)
- Luping Z Huang
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, CA 94025, USA
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88
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Pérez XA, Quik M. Focus on α4β2* and α6β2* nAChRs for Parkinson's Disease Therapeutics. MOLECULAR AND CELLULAR PHARMACOLOGY 2011; 3:1-6. [PMID: 21499569 PMCID: PMC3076673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
L-dopa is one of the best treatments for the motor symptoms of Parkinson's disease. However, its use is limited by the fact that it provides only symptomatic relief and chronic therapy leads to dyskinesias. There is therefore a continual search for novel therapeutic approaches. Nicotine, a drug that acts at nicotinic acetylcholine receptors (nAChRs), has been shown to protect against nigrostriatal damage and reduce L-dopa-induced dyskinesias. NAChRs may therefore represent novel targets for Parkinson's disease management. Since there are multiple nAChRs throughout the body, it is important to understand the subtypes involved in striatal function to allow for the development of drugs with optimal beneficial effects. Here we discuss recent work from our laboratory which indicates that α6β2* and α4β2* nAChRs are key in regulating striatal dopaminergic function. Experiments in parkinsonian rats using cyclic voltammetry showed that both α6β2* and α4β2* nAChR-mediated evoked-dopamine release in striatal slices is affected by nigrostriatal damage. These subtypes also appear to be important for neuroprotection against nigrostriatal damage and the nicotine-mediated reduction in L-dopa-induced dyskinesias in parkinsonian animal models. Our combined findings indicate that α4β2* and α6β2* nAChRs may represent useful therapeutic targets for Parkinson's disease.
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Affiliation(s)
- Xiomara A Pérez
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, California
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89
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Oksenberg A. Alleviation of severe restless legs syndrome (RLS) symptoms by cigarette smoking. J Clin Sleep Med 2010; 6:489-490. [PMID: 20957852 PMCID: PMC2952755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Cigarette smoking is in general considered an aggravating factor for restless legs syndrome (RLS). The author presents a case in which cigarette smoking has produced for many years a consistent and effective alleviation of RLS symptoms.
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Affiliation(s)
- Arie Oksenberg
- Sleep Disorders Unit, Loewenstein Hospital--Rehabilitation Center, Raanana, Israel.
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90
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Manda VK, Mittapalli RK, Geldenhuys WJ, Lockman PR. Chronic exposure to nicotine and saquinavir decreases endothelial Notch-4 expression and disrupts blood-brain barrier integrity. J Neurochem 2010; 115:515-25. [PMID: 20722969 DOI: 10.1111/j.1471-4159.2010.06948.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Since the advent of HAART, there have been substantial improvements in HIV patient survival; however, the prevalence of HIV associated dementia has increased. Importantly, HIV positive individuals who smoke progress to HIV associated neurological conditions faster than those who do not. Recent in vitro data have shown that pharmacological levels of saquinavir causes endothelial oxidative stress and significantly decreases Notch-4 expression, a primary protein involved in maintaining stability of blood-brain barrier (BBB) endothelium. This is concerning as nicotine can also generate reactive oxygen species in endothelium. It is largely unknown if pharmacological doses of these drugs can cause a similar in vivo down-regulation of Notch-4 and if there is a concurrent destabilization of the integrity of the BBB. The data herein show: (i) nicotine and protease inhibitors cause an additive oxidative stress burden in endothelium; (ii) that the integrity of the BBB is disrupted after concurrent chronic nicotine and protease inhibitor administration; and (iii) that BBB endothelial dysfunction is correlated with a decrease in Notch-4 and ZO-1 expression. Considering the high prevalence of smoking in the HIV infected population (3- to 4-fold higher than in the general population) this data must be followed up to determine if all protease inhibitors cause a similar BBB disruption or if there is a safer alternative. In addition, this data may suggest that the induced BBB disruption may allow foreign molecules to gain access to brain and be a contributing factor to the slow progression of HIV associated dementia.
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Affiliation(s)
- Vamshi K Manda
- Texas Tech University Health Sciences Center, School of Pharmacy, Department of Pharmaceutical Sciences, Amarillo, Texas 79106-1712, USA
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91
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Perez XA, Bordia T, McIntosh JM, Quik M. α6ß2* and α4ß2* nicotinic receptors both regulate dopamine signaling with increased nigrostriatal damage: relevance to Parkinson's disease. Mol Pharmacol 2010; 78:971-80. [PMID: 20732972 DOI: 10.1124/mol.110.067561] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nicotinic receptors (nAChRs) are important modulators of dopaminergic transmission in striatum, a region critical to Parkinson's disease. The nAChRs mainly involved are the α6β2* and α4β2* subtypes. Lesion studies show that the α6β2* receptor is decreased to a much greater extent with nigrostriatal damage than the α4β2* subtype raising the question whether this latter nAChR population is more important with increased nigrostriatal damage. To address this, we investigated the effect of varying nigrostriatal damage on α6β2* and α4β2* receptor-modulated dopamine signaling using cyclic voltammetry. This approach offers the advantage that changes in dopamine release can be observed under different neuronal firing conditions. Total single-pulse-evoked dopamine release decreased in direct proportion to declines in the dopamine transporter and dopamine uptake. We next used α-conotoxinMII and mecamylamine to understand the role of the α4β2* and α6β2* subtypes in release. Single-pulse-stimulated α6β2* and α4β2* receptor dopamine release decreased to a similar extent with increasing nigrostriatal damage, indicating that both subtypes contribute to the control of dopaminergic transmission with lesioning. Total burst-stimulated dopamine release also decreased proportionately with nigrostriatal damage. However, the role of the α4β2* and α6β2* nAChRs varied with different degrees of lesioning, suggesting that the two subtypes play a unique function with burst firing, with a somewhat more prominent and possibly more selective role for the α6β2* subtype. These data have important therapeutic implications because they suggest that drugs directed to both α4β2* and α6β2* nAChRs may be useful in the treatment of neurological disorders such as Parkinson's disease.
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Affiliation(s)
- Xiomara A Perez
- Center for Health Sciences, SRI International, 333 Ravenswood Ave, Menlo Park, California 94025, USA
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92
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Abin-Carriquiry JA, Urbanavicius J, Scorza C, Rebolledo-Fuentes M, Wonnacott S, Cassels BK, Dajas F. Increase in locomotor activity after acute administration of the nicotinic receptor agonist 3-bromocytisine in rats. Eur J Pharmacol 2010; 634:89-94. [DOI: 10.1016/j.ejphar.2010.02.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 01/28/2010] [Accepted: 02/14/2010] [Indexed: 01/19/2023]
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93
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Singh K, Singh S, Singhal NK, Sharma A, Parmar D, Singh MP. Nicotine- and caffeine-mediated changes in gene expression patterns of MPTP-lesioned mouse striatum: Implications in neuroprotection mechanism. Chem Biol Interact 2010; 185:81-93. [DOI: 10.1016/j.cbi.2010.03.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 02/27/2010] [Accepted: 03/07/2010] [Indexed: 01/21/2023]
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Localisation of pre- and postsynaptic cholinergic markers in the human brain. Behav Brain Res 2010; 221:341-55. [PMID: 20170687 DOI: 10.1016/j.bbr.2010.02.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 02/10/2010] [Indexed: 12/20/2022]
Abstract
The cholinergic neurotransmission in the central nervous system plays an important role in modulating cognitive processes such as learning, memory, arousal and sleep as well as in modulating locomotor activity. Dysfunction of the central cholinergic system is involved in numerous neuropsychiatric diseases. This review will provide a synopsis on the regional localisation of cholinergic and cholinoceptive structures within the adult human brain. On the cholinergic site data based on the distribution of choline acetyltransferase-immunoreactive structures are in the focus, complemented by data from acetylcholinesterase and vesicular acetylcholine transporter studies. On the cholinoceptive site, the distribution and localisation of receptors that transduce the acetylcholine message, i.e. the muscarinic and the nicotinic acetylcholine receptors is summarized. In addition to these data obtained on post mortem brain an overview of markers which allow for the in vivo monitoring of the cholinergic system in the brain is given. The detailed knowledge on the distribution and localisation of cholinergic markers in human brain will provide further information on the cholinergic circuits of neurotransmission - a prerequisite for the interpretation of in vivo imaging data and the development of selective diagnostic and therapeutic compounds.
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