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Proshin AT. Comparative Analysis of Dopaminergic and Cholinergic Mechanisms of Sensory and Sensorimotor Gating in Healthy Individuals and in Patients With Schizophrenia. Front Behav Neurosci 2022; 16:887312. [PMID: 35846783 PMCID: PMC9282644 DOI: 10.3389/fnbeh.2022.887312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Sensory and sensorimotor gating provide the early processing of information under conditions of rapid presentation of multiple stimuli. Gating deficiency is observed in various psychopathologies, in particular, in schizophrenia. However, there is also a significant proportion of people in the general population with low filtration rates who do not show any noticeable cognitive decline. The review article presents a comparative analysis of existing data on the peculiarities of cholinergic and dopaminergic mechanisms associated with lowering gating in healthy individuals and in patients with schizophrenia. The differences in gating mechanisms in cohorts of healthy individuals and those with schizophrenia are discussed.
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Di Lascio S, Fornasari D, Benfante R. The Human-Restricted Isoform of the α7 nAChR, CHRFAM7A: A Double-Edged Sword in Neurological and Inflammatory Disorders. Int J Mol Sci 2022; 23:ijms23073463. [PMID: 35408823 PMCID: PMC8998457 DOI: 10.3390/ijms23073463] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/13/2022] [Accepted: 03/21/2022] [Indexed: 12/13/2022] Open
Abstract
CHRFAM7A is a relatively recent and exclusively human gene arising from the partial duplication of exons 5 to 10 of the α7 neuronal nicotinic acetylcholine receptor subunit (α7 nAChR) encoding gene, CHRNA7. CHRNA7 is related to several disorders that involve cognitive deficits, including neuropsychiatric, neurodegenerative, and inflammatory disorders. In extra-neuronal tissues, α7nAChR plays an important role in proliferation, differentiation, migration, adhesion, cell contact, apoptosis, angiogenesis, and tumor progression, as well as in the modulation of the inflammatory response through the “cholinergic anti-inflammatory pathway”. CHRFAM7A translates the dupα7 protein in a multitude of cell lines and heterologous systems, while maintaining processing and trafficking that are very similar to the full-length form. It does not form functional ion channel receptors alone. In the presence of CHRNA7 gene products, dupα7 can assemble and form heteromeric receptors that, in order to be functional, should include at least two α7 subunits to form the agonist binding site. When incorporated into the receptor, in vitro and in vivo data showed that dupα7 negatively modulated α7 activity, probably due to a reduction in the number of ACh binding sites. Very recent data in the literature report that the presence of the duplicated gene may be responsible for the translational gap in several human diseases. Here, we will review the studies that have been conducted on CHRFAM7A in different pathologies, with the intent of providing evidence regarding when and how the expression of this duplicated gene may be beneficial or detrimental in the pathogenesis, and eventually in the therapeutic response, to CHRNA7-related neurological and non-neurological diseases.
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Affiliation(s)
- Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, 20129 Milan, Italy; (S.D.L.); (D.F.)
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, 20129 Milan, Italy; (S.D.L.); (D.F.)
- CNR Institute of Neuroscience, 20845 Vedano al Lambro, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, 20129 Milan, Italy; (S.D.L.); (D.F.)
- CNR Institute of Neuroscience, 20845 Vedano al Lambro, Italy
- NeuroMi, Milan Center for Neuroscience, University of Milano Bicocca, 20126 Milan, Italy
- Correspondence:
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Neurophysiology in psychosis: The quest for disease biomarkers. Transl Psychiatry 2022; 12:100. [PMID: 35277479 PMCID: PMC8917164 DOI: 10.1038/s41398-022-01860-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 01/11/2023] Open
Abstract
Psychotic disorders affect 3% of the population at some stage in life, are a leading cause of disability, and impose a great economic burden on society. Major breakthroughs in the genetics of psychosis have not yet been matched by an understanding of its neurobiology. Biomarkers of perception and cognition obtained through non-invasive neurophysiological tools, especially EEG, offer a unique opportunity to gain mechanistic insights. Techniques for measuring neurophysiological markers are inexpensive and ubiquitous, thus having the potential as an accessible tool for patient stratification towards early treatments leading to better outcomes. In this paper, we review the literature on neurophysiological markers for psychosis and their relevant disease mechanisms, mainly covering event-related potentials including P50/N100 sensory gating, mismatch negativity, and the N100 and P300 waveforms. While several neurophysiological deficits are well established in patients with psychosis, more research is needed to study neurophysiological markers in their unaffected relatives and individuals at clinical high risk. We need to harness EEG to investigate markers of disease risk as key steps to elucidate the aetiology of psychosis and facilitate earlier detection and treatment.
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Sex differences in P50 inhibition defects with psychopathology and cognition in patients with first-episode schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2021; 111:110380. [PMID: 34111493 DOI: 10.1016/j.pnpbp.2021.110380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/19/2021] [Accepted: 06/04/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND A large number of studies have shown that the pathophysiology of schizophrenia may be involved in sensory gating that appears to be P50 inhibition. However, few studies have investigated the relationship between clinical symptoms, cognitive impairment and sensory gating disorders in patients with first-episode schizophrenia. The purpose of this study was to explore the sex differences in the relationship between clinical symptoms, cognitive impairment and P50 inhibition defects in patients with first-episode schizophrenia, which has not been reported. METHODS 130 patients with first-episode schizophrenia (53 males and 77 females) and 189 healthy controls (87 males and 102 females) participated in the study. Positive and Negative Syndrome Scale (PANSS) was used to evaluate the patients' psychopathological symptoms, and the 64-channel electroencephalogram (EEG) system was used to record the P50 inhibition. RESULTS Male patients had higher PANSS negative symptom, general psychopathology, cognitive factor and total scores than female patients (all p < 0.01). The S1 amplitude was smaller in male than female patients (all p < 0.05). Multiple regression analysis showed that in male patients, S1 latency was contributor to negative symptoms, while S1 latency, S2 latency, age, and smoking status were contributors to cognitive factor (all p < 0.05). In female patients, no P50 component was found to be an independent contributor to PANSS scores (all p > 0.05). CONCLUSIONS Our results indicate that there is a sex difference in the relationship between clinical symptoms, cognitive impairment and P50 inhibition defects in Chinese Han patients with first-episode schizophrenia.
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Hills PJ, Vasilev MR, Ford P, Snell L, Whitworth E, Parsons T, Morisson R, Silveira A, Angele B. Sensory gating is related to positive and disorganised schizotypy in contrast to smooth pursuit eye movements and latent inhibition. Neuropsychologia 2021; 161:107989. [PMID: 34419489 DOI: 10.1016/j.neuropsychologia.2021.107989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/30/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
Since the characteristics and symptoms of both schizophrenia and schizotypy are manifested heterogeneously, it is possible that different endophenotypes and neurophysiological measures (sensory gating and smooth pursuit eye movement errors) represent different clusters of symptoms. Participants (N = 205) underwent a standard conditioned-pairing paradigm to establish their sensory gating ratio, a smooth-pursuit eye-movement task, a latent inhibition task, and completed the Schizotypal Personality Questionnaire. A Multidimensional Scaling analysis revealed that sensory gating was related to positive and disorganised dimensions of schizotypy. Latent inhibition and prepulse inhibition were not related to any dimension of schizotypy. Smooth pursuit eye movement error was unrelated to sensory gating and latent inhibition, but was related to negative dimensions of schizotypy. Our findings suggest that the symptom clusters associated with two main endophenotypes are largely independent. To fully understand symptomology and outcomes of schizotypal traits, the different subtypes of schizotypy (and potentially, schizophrenia) ought to be considered separately rather than together.
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Rovný R, Besterciová D, Riečanský I. Genetic Determinants of Gating Functions: Do We Get Closer to Understanding Schizophrenia Etiopathogenesis? Front Psychiatry 2020; 11:550225. [PMID: 33324248 PMCID: PMC7723973 DOI: 10.3389/fpsyt.2020.550225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/12/2020] [Indexed: 11/13/2022] Open
Abstract
Deficits in the gating of sensory stimuli, i.e., the ability to suppress the processing of irrelevant sensory input, are considered to play an important role in the pathogenesis of several neuropsychiatric disorders, in particular schizophrenia. Gating is disrupted both in schizophrenia patients and their unaffected relatives, suggesting that gating deficit may represent a biomarker associated with a genetic liability to the disorder. To assess the strength of the evidence for the etiopathogenetic links between genetic variation, gating efficiency, and schizophrenia, we carried out a systematic review of human genetic association studies of sensory gating (suppression of the P50 component of the auditory event-related brain potential) and sensorimotor gating (prepulse inhibition of the acoustic startle response). Sixty-three full-text articles met the eligibility criteria for inclusion in the review. In total, 117 genetic variants were reported to be associated with gating functions: 33 variants for sensory gating, 80 variants for sensorimotor gating, and four variants for both sensory and sensorimotor gating. However, only five of these associations (four for prepulse inhibition-CHRNA3 rs1317286, COMT rs4680, HTR2A rs6311, and TCF4 rs9960767, and one for P50 suppression-CHRNA7 rs67158670) were consistently replicated in independent samples. Although these variants and genes were all implicated in schizophrenia in research studies, only two polymorphisms (HTR2A rs6311 and TCF4 rs9960767) were also reported to be associated with schizophrenia at a meta-analytic or genome-wide level of evidence. Thus, although gating is widely considered as an important endophenotype of schizophrenia, these findings demonstrate that evidence for a common genetic etiology of impaired gating functions and schizophrenia is yet unsatisfactory, warranting further studies in this field.
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Affiliation(s)
- Rastislav Rovný
- Department of Behavioural Neuroscience, Institute of Normal and Pathological Physiology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Dominika Besterciová
- Department of Behavioural Neuroscience, Institute of Normal and Pathological Physiology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Igor Riečanský
- Department of Behavioural Neuroscience, Institute of Normal and Pathological Physiology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
- Social, Cognitive and Affective Neuroscience Unit, Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
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P50 inhibition deficit in patients with chronic schizophrenia: Relationship with cognitive impairment of MATRICS consensus cognitive battery. Schizophr Res 2020; 215:105-112. [PMID: 31780341 DOI: 10.1016/j.schres.2019.11.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/01/2019] [Accepted: 11/05/2019] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Cognitive impairment is a core symptom of schizophrenia (SCZ); however, its pathophysiological mechanisms remain unclear. The sensory gating (SG) deficits reflected by P50 inhibition are recurring in SCZ, and this inhibition may be related to the cognitive deficits seen in these individuals. This study aimed to investigate the relationship between P50 inhibition and cognitive dysfunction in SCZ, which has not been fully investigated up to this point. METHODS A total of 270 individuals with chronic SCZ and 116 healthy controls were enrolled in the study. Psychopathology of SCZ was rated by the positive and negative syndrome scale (PANSS), while cognitive function and P50 inhibition of subjects were assessed by the MATRICS Consensus Cognitive Battery (MCCB) and the electroencephalography system. RESULTS The MCCB total and its 10 index scores were significantly lower in patients than those in healthy controls (all p < 0.001). SCZ patients had a lower amplitude of S1, and higher P50 ratio than healthy controls (both p < 0.01). However, there were no significant correlations between the P50 ratio and any of the PANSS total and its subscale scores in SCZ patients (all p > 0.05). Moreover, no correlation was found between the P50 components and the MCCB scores (all p > 0.05). CONCLUSIONS Our findings suggest that the P50 inhibition deficits occur in Chinese individuals with SCZ, which may not be associated with their clinical symptoms and cognitive impairment.
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Xue Y, He X, Yang T, Wang Y, Liu Z, Zhang G, Wang Y, Wang K, Zhang L, Zhang L. Discovery of fused heterocyclic carboxamide derivatives as novel α7-nAChR agonists: Synthesis, preliminary SAR and biological evaluation. Eur J Med Chem 2019; 182:111618. [PMID: 31434041 DOI: 10.1016/j.ejmech.2019.111618] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/10/2019] [Accepted: 08/11/2019] [Indexed: 10/26/2022]
Abstract
The α7 nicotinic acetylcholine receptor (α7 nAChR) has emerged as a promising therapeutic target for schizophrenia. In our previous work, a novel series of α7-nAChR agonists bearing scaffold of indolizine were discovered. To explore the effect of aromaticity on the activity and find more active agents, herein, fused heterocyclic carboxamide derivatives were designed and synthesized in this study. Based on the evaluation by two-electrode voltage clamp in Xenopus oocytes, 27 of the synthesized compounds showed obvious agonism of α7 nAChR. Particularly, compounds 10a and 10e showed significantly higher Emax than EVP-6124. The result illustrated the importance of aromaticity to the activity of agonism. Compound 10a, which showed EC50 of 1.88 μM and Emax of 72.4%, was further characterized comprehensively, including co-application with type II positive allosteric modulator PNU-120596, selectivity with other closely related ligand-gated ion channel, etc. The results showed that 10a showed moderate selectivity over other subtypes such as α4β2 and α3β4 nAChR. 10a evoked α7-like currents that were inhibited by MLA and enhanced in the presence of the α7 PAM PNU-120596. The analysis of binding mode and understanding of structure-activity relationship provided insights to develop more potent novel α7-nAChR agonists.
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Affiliation(s)
- Yu Xue
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China.
| | - Xiaomeng He
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China.
| | - Taoyi Yang
- Department of Molecular and Cellular Pharmacology, PKU-IDG/McGovern Institute for Brain Research, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China
| | - Yuxi Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China
| | - Zhenming Liu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China
| | - Guisen Zhang
- Jiangsu Nhwa Pharmaceutical Co. Ltd, 69 Minzhu South Road, Xuzhou, Jiangsu, 221116, PR China
| | - Yanxing Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China
| | - Kewei Wang
- Department of Molecular and Cellular Pharmacology, PKU-IDG/McGovern Institute for Brain Research, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China.
| | - Liangren Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China.
| | - Lihe Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, PR China.
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Thibaut F, Boutros NN, Jarema M, Oranje B, Hasan A, Daskalakis ZJ, Wichniak A, Schmitt A, Riederer P, Falkai P. Consensus paper of the WFSBP Task Force on Biological Markers: Criteria for biomarkers and endophenotypes of schizophrenia part I: Neurophysiology. World J Biol Psychiatry 2016. [PMID: 26213111 DOI: 10.3109/15622975.2015.1050061] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The neurophysiological components that have been proposed as biomarkers or as endophenotypes for schizophrenia can be measured through electroencephalography (EEG) and magnetoencephalography (MEG), transcranial magnetic stimulation (TMS), polysomnography (PSG), registration of event-related potentials (ERPs), assessment of smooth pursuit eye movements (SPEM) and antisaccade paradigms. Most of them demonstrate deficits in schizophrenia, show at least moderate stability over time and do not depend on clinical status, which means that they fulfil the criteria as valid endophenotypes for genetic studies. Deficits in cortical inhibition and plasticity measured using non-invasive brain stimulation techniques seem promising markers of outcome and prognosis. However the utility of these markers as biomarkers for predicting conversion to psychosis, response to treatments, or for tracking disease progression needs to be further studied.
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Affiliation(s)
- Florence Thibaut
- Department of Psychiatry, University Hospital Cochin (site Tarnier), University of Paris-Descartes, INSERM U 894 Centre Psychiatry and Neurosciences , Paris , France
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Synthesis and biological activities of indolizine derivatives as alpha-7 nAChR agonists. Eur J Med Chem 2016; 115:94-108. [PMID: 26994846 DOI: 10.1016/j.ejmech.2016.03.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 12/16/2022]
Abstract
Human α7 nicotinic acetylcholine receptor (nAChR) is a promising therapeutic target for the treatment of schizophrenia accompanied with cognitive impairment. Herein, we report the synthesis and agonistic activities of a series of indolizine derivatives targeting to α7 nAChR. The results show that all synthesized compounds have affinity to α7 nAChR and some give strong agonistic activity, particularly most active agonists show higher potency than control EVP-6124. The docking and structure-activity relationship studies provide insights to develop more potent novel α7 nAChR agonists.
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Damiano JA, Mullen SA, Hildebrand MS, Bellows ST, Lawrence KM, Arsov T, Dibbens L, Major H, Dahl HHM, Mefford HC, Darbro BW, Scheffer IE, Berkovic SF. Evaluation of multiple putative risk alleles within the 15q13.3 region for genetic generalized epilepsy. Epilepsy Res 2015; 117:70-3. [DOI: 10.1016/j.eplepsyres.2015.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/28/2015] [Accepted: 09/07/2015] [Indexed: 12/11/2022]
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Bertrand D, Lee CHL, Flood D, Marger F, Donnelly-Roberts D. Therapeutic Potential of α7 Nicotinic Acetylcholine Receptors. Pharmacol Rev 2015; 67:1025-73. [DOI: 10.1124/pr.113.008581] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Sinkus ML, Graw S, Freedman R, Ross RG, Lester HA, Leonard S. The human CHRNA7 and CHRFAM7A genes: A review of the genetics, regulation, and function. Neuropharmacology 2015; 96:274-88. [PMID: 25701707 PMCID: PMC4486515 DOI: 10.1016/j.neuropharm.2015.02.006] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 02/04/2015] [Accepted: 02/06/2015] [Indexed: 01/16/2023]
Abstract
The human α7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) is ubiquitously expressed in both the central nervous system and in the periphery. CHRNA7 is genetically linked to multiple disorders with cognitive deficits, including schizophrenia, bipolar disorder, ADHD, epilepsy, Alzheimer's disease, and Rett syndrome. The regulation of CHRNA7 is complex; more than a dozen mechanisms are known, one of which is a partial duplication of the parent gene. Exons 5-10 of CHRNA7 on chromosome 15 were duplicated and inserted 1.6 Mb upstream of CHRNA7, interrupting an earlier partial duplication of two other genes. The chimeric CHRFAM7A gene product, dupα7, assembles with α7 subunits, resulting in a dominant negative regulation of function. The duplication is human specific, occurring neither in primates nor in rodents. The duplicated α7 sequence in exons 5-10 of CHRFAM7A is almost identical to CHRNA7, and thus is not completely queried in high throughput genetic studies (GWAS). Further, pre-clinical animal models of the α7nAChR utilized in drug development research do not have CHRFAM7A (dupα7) and cannot fully model human drug responses. The wide expression of CHRNA7, its multiple functions and modes of regulation present challenges for study of this gene in disease. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.
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Affiliation(s)
- Melissa L Sinkus
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA.
| | - Sharon Graw
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA.
| | - Robert Freedman
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA; Veterans Affairs Medical Research Center, Denver, CO 80262, USA.
| | - Randal G Ross
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA.
| | - Henry A Lester
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Sherry Leonard
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA; Veterans Affairs Medical Research Center, Denver, CO 80262, USA.
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Knott V, Impey D, Choueiry J, Smith D, de la Salle S, Saghir S, Smith M, Beaudry E, Ilivitsky V, Labelle A. An acute dose, randomized trial of the effects of CDP-Choline on Mismatch Negativity (MMN) in healthy volunteers stratified by deviance detection level. ACTA ACUST UNITED AC 2015. [DOI: 10.1186/s40810-014-0002-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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15
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Knott V, Smith D, de la Salle S, Impey D, Choueiry J, Beaudry E, Smith M, Saghir S, Ilivitsky V, Labelle A. CDP-choline: effects of the procholine supplement on sensory gating and executive function in healthy volunteers stratified for low, medium and high P50 suppression. J Psychopharmacol 2014; 28:1095-108. [PMID: 25315828 DOI: 10.1177/0269881114553254] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Diminished auditory sensory gating and associated neurocognitive deficits in schizophrenia have been linked to altered expression and function of the alpha-7 nicotinic acetycholinergic receptor (α7 nAChR), the targeting of which may have treatment potential. Choline is a selective α7 nAChR agonist and the aim of this study was to determine whether cytidine 5'-diphosphocholine (CDP-choline), or citicoline, a dietary source of choline, increases sensory gating and cognition in healthy volunteers stratified for gating level. In a randomized, placebo-controlled, double-blind design involving acute administration of low, moderate doses (500 mg, 1000 mg) of CDP-choline, 24 healthy volunteers were assessed for auditory gating as indexed by suppression of the P50 event-related potential (ERP) in a paired-stimulus (S1, S2) paradigm, and for executive function as measured by the Groton Maze Learning Task (GMLT) of the CogState Schizophrenia Battery. CDP-choline improved gating (1000 mg) and suppression of the S2 P50 response (500 mg, 1000 mg), with the effects being selective for individuals with low gating (suppression) levels. Tentative support was also shown for increased GMLT performance (500 mg) in low suppressors. These preliminary findings with CDP-choline in a healthy, schizophrenia-like surrogate sample are consistent with a α7 nAChR mechanism and support further trials with choline as a pro-cognitive strategy.
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Affiliation(s)
- Verner Knott
- Institute of Mental Health Research, University of Ottawa, Ottawa, ON, Canada Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada School of Psychology, University of Ottawa, Ottawa, ON, Canada Department of Psychiatry, University of Ottawa, Ottawa, ON, Canada
| | - Dylan Smith
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | | | - Danielle Impey
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Joelle Choueiry
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Elise Beaudry
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Meaghan Smith
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Salman Saghir
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Vadim Ilivitsky
- Department of Psychiatry, University of Ottawa, Ottawa, ON, Canada
| | - Alain Labelle
- Department of Psychiatry, University of Ottawa, Ottawa, ON, Canada
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Sklar AL, Nixon SJ. Disruption of sensory gating by moderate alcohol doses. Psychopharmacology (Berl) 2014; 231:4393-402. [PMID: 24800896 PMCID: PMC4209187 DOI: 10.1007/s00213-014-3591-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 04/08/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Evidence from a growing body of literature suggests that alcohol, even at moderate-dose levels, disrupts the ability to ignore distractors. However, little work has been done to elucidate the neural processes underlying this deficit. OBJECTIVE The present study was conducted to determine if low-to-moderate alcohol doses affect sensory gating, an electrophysiological phenomenon believed to reflect the pre-attentive filtering of irrelevant sensory information. METHODS Sixty social drinkers were administered one of three doses intended to produce breath alcohol concentrations of 0.0% (placebo), 0.04% (i.e., low dose), and 0.065% (i.e., moderate dose). A paired-click paradigm consisting of 100 pairs of identical tones (S1 and S2) was used to assess sensory gating. Amplitudes of P50, N100, and P200 auditory evoked potentials (AEPs) were used to calculate gating difference (S1-S2) and ratio (S2/S1) scores. RESULTS The moderate alcohol dose significantly decreased P50 and N100 gating relative to placebo. Comparisons between the difference and ratio scores helped characterize the gating mechanisms affected at these stages of information processing. Alcohol did not alter P200 sensory gating. CONCLUSIONS These data suggest that alcohol disrupts pre-attentional sensory-filtering processes at breath alcohol concentrations (BrACs) below the current 0.08% legal limit. Future studies should perform a combined assessment of sensory gating and selective attention to better understand the relationship between these two alcohol-induced deficits.
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Affiliation(s)
- Alfredo L. Sklar
- University of Florida, Department of Psychiatry, Gainesville, FL 32610, USA
| | - Sara Jo Nixon
- University of Florida, Department of Psychiatry, Gainesville, FL 32610, USA
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Wang Y, Xiao C, Indersmitten T, Freedman R, Leonard S, Lester HA. The duplicated α7 subunits assemble and form functional nicotinic receptors with the full-length α7. J Biol Chem 2014; 289:26451-26463. [PMID: 25056953 DOI: 10.1074/jbc.m114.582858] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The α7 nicotinic acetylcholine receptor gene (CHRNA7) is linked to schizophrenia. A partial duplication of CHRNA7 (CHRFAM7A) is found in humans on 15q13-14. Exon 6 of CHRFAM7A harbors a 2-bp deletion polymorphism, CHRFAM7AΔ2bp, which is also associated with schizophrenia. To understand the effects of the duplicated subunits on α7 receptors, we fused α7, dupα7, and dupΔα7 subunits with various fluorescent proteins. The duplicated subunits co-localized with full-length α7 subunits in mouse neuroblastoma cells (Neuro2a) as well as rat hippocampal neurons. We investigated the interaction between the duplicated subunits and full-length α7 by measuring Förster resonance energy transfer using donor recovery after photobleaching and fluorescence lifetime imaging microscopy. The results revealed that the duplicated proteins co-assemble with α7. In electrophysiological studies, Leu at the 9'-position in the M2 membrane-spanning segment was replaced with Cys in dupα7 or dupΔα7, and constructs were co-transfected with full-length α7 in Neuro2a cells. Exposure to ethylammonium methanethiosulfonate inhibited acetylcholine-induced currents, showing that the assembled functional nicotinic acetylcholine receptors (nAChRs) included the duplicated subunit. Incorporation of dupα7 and dupΔα7 subunits modestly changes the sensitivity of receptors to choline and varenicline. Thus, the duplicated proteins are assembled and transported to the cell membrane together with full-length α7 subunits and alter the function of the nAChRs. The characterization of dupα7 and dupΔα7 as well as their influence on α7 nAChRs may help explain the pathophysiology of schizophrenia and may suggest therapeutic strategies.
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Affiliation(s)
- Ying Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125 and
| | - Cheng Xiao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125 and
| | - Tim Indersmitten
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125 and
| | - Robert Freedman
- Department of Psychiatry, University of Colorado at Denver, Denver, Colorado 80045
| | - Sherry Leonard
- Department of Psychiatry, University of Colorado at Denver, Denver, Colorado 80045
| | - Henry A Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125 and.
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Freedman R. α7-Nicotinic Acetylcholine Receptor Agonists for Cognitive Enhancement in Schizophrenia. Annu Rev Med 2014; 65:245-61. [DOI: 10.1146/annurev-med-092112-142937] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Robert Freedman
- Department of Psychiatry, University of Colorado Denver School of Medicine, Aurora, Colorado 80045;
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Liu X, Hong X, Chan RCK, Kong F, Peng Z, Wan X, Wang C, Cheng L. Association study of polymorphisms in the alpha 7 nicotinic acetylcholine receptor subunit and catechol-o-methyl transferase genes with sensory gating in first-episode schizophrenia. Psychiatry Res 2013; 209:431-8. [PMID: 23598060 DOI: 10.1016/j.psychres.2013.03.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 03/02/2013] [Accepted: 03/26/2013] [Indexed: 11/15/2022]
Abstract
The purpose of the current study was to explore the association of auditory P50 sensory gating (P50) and prepulse inhibition (PPI) of schizophrenia with polymorphisms in the CHRNA7 and COMT genes. One hundred and fourty patients with schizophrenia participated in this study. They were administered the tests P50 and PPI. Moreover, three single nucleotide polymorphisms (SNPs) (rs2337980, rs1909884 and rs883473) in CHRNA7 and three SNPs (rs4680, rs737865 and rs165599) in COMT were selected to be genotyped by polyacrylamide gel microarray techniques. P50 index showed significant reduction in S2 amplitude between wild-type and mutation groups in the COMT rs4680. S1 amplitude of mutation group in the COMT rs737865 was also lower compared to wild-type group. PPI index revealed a shorter pulse latency of mutation group in the rs4680. The suppression ratio of mutation group was lower in COMT rs165599. Negative findings were shown between comparisons in all the CHRNA7 SNPs. We find that P50 and PPI may be influenced by COMT rs4680 polymorphisms in schizophrenia; more excitingly, we find that P50 might be influenced by COMT rs737865 polymorphisms and PPI may be influenced by COMT rs165599 polymorphisms in schizophrenia, and their mutations are associated with the reduction of the risk of P50 or PPI defects in schizophrenia. Futher studies with a larger number of subjects are needed to verify the present findings.
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Affiliation(s)
- Xia Liu
- Mental Health Center, Medical College of Shantou University, Shantou, China; Mental health Hospital of Jining, Jining, China
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Bakanidze G, Roinishvili M, Chkonia E, Kitzrow W, Richter S, Neumann K, Herzog MH, Brand A, Puls I. Association of the Nicotinic Receptor α7 Subunit Gene (CHRNA7) with Schizophrenia and Visual Backward Masking. Front Psychiatry 2013; 4:133. [PMID: 24155726 PMCID: PMC3805058 DOI: 10.3389/fpsyt.2013.00133] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 10/01/2013] [Indexed: 01/16/2023] Open
Abstract
The nicotinic system is involved in the pathophysiology of schizophrenia. However, very little is known about its genetic basis and how it relates to clinical symptoms and potentially pharmacological intervention. Here, we investigated five single nucleotide polymorphisms (SNPs) [rs3826029] [rs2337506] [rs982574] [rs904952] [rs2337980] of the cholinergic nicotinic receptor gene, alpha 7 subunit (CHRNA7) and their association to schizophrenia. We found an association with rs904952 (p = 0.009) in a German sample of 224 schizophrenic patients and 224 healthy control subjects. The same trend was shown in an independent Georgian sample of 50 schizophrenic patients, 57 first order unaffected relatives, and 51 healthy controls. In addition, visual backward masking (VBM), a sensitive test for early visual information processing, was assessed in the Georgian sample. In line with prior studies, VBM performance deficits were much more pronounced in schizophrenic patients and their unaffected relatives compared to healthy controls (schizophrenic patients: 156 ms; unaffected relatives: 60 ms; healthy controls: 33 ms). VBM was strongly correlated with SNP rs904952 (H[2] = 7.3, p = 0.026). Our results further support the notion that changes in the nicotinic system are involved in schizophrenia and open the avenue for pharmacological intervention.
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Affiliation(s)
- George Bakanidze
- Genetic Section, Department of Psychiatry and Psychotherapy, CCM, Charité University Medicine, Berlin, Germany
| | - Maya Roinishvili
- Department of Behaviour and Cognitive Functions, I. Beritashvili Institute of Physiology, Tbilisi, Georgia
- Institute of Cognitive Neurosciences, Agricultural University of Georgia, Tbilisi, Georgia
| | - Eka Chkonia
- Institute of Cognitive Neurosciences, Agricultural University of Georgia, Tbilisi, Georgia
- Department of Psychiatry, Tbilisi State Medical University, Tbilisi, Georgia
| | - Werner Kitzrow
- Genetic Section, Department of Psychiatry and Psychotherapy, CCM, Charité University Medicine, Berlin, Germany
| | - Sarina Richter
- Genetic Section, Department of Psychiatry and Psychotherapy, CCM, Charité University Medicine, Berlin, Germany
| | - Konrad Neumann
- Institute of Biometry and Clinical Epidemiology, CCM, Charite University, Berlin, Germany
| | - Michael H. Herzog
- Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Andreas Brand
- Center for Psychiatry and Psychotherapy, Klinikum Bremen-Ost, Bremen, Germany
| | - Imke Puls
- Genetic Section, Department of Psychiatry and Psychotherapy, CCM, Charité University Medicine, Berlin, Germany
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21
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Rozycka A, Dorszewska J, Steinborn B, Lianeri M, Winczewska-Wiktor A, Sniezawska A, Wisniewska K, Jagodzinski PP. Association study of the 2-bp deletion polymorphism in exon 6 of the CHRFAM7A gene with idiopathic generalized epilepsy. DNA Cell Biol 2013; 32:640-7. [PMID: 24024466 DOI: 10.1089/dna.2012.1880] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is evidence of linkage between the 15q13-q14 locus, containing the gene encoding the α7 subunit (CHRNA7) of the neuronal nicotinic acetylcholine receptor (nAChR) and its partially duplicated isoform (CHRFAM7A), and epilepsy. Additionally, a 2-bp deletion polymorphism (c.497-498delTG; rs67158670) in CHRFAM7A, resulting in a frame shift and truncation of the protein product, is associated with some neurological diseases. This study was designed to explore the possibility of an association of the c.497-498delTG polymorphism of CHRFAM7A with idiopathic generalized epilepsies (IGEs) in Polish children and young patients. The study included 197 IGE patients and 258 unrelated healthy individuals. The frequency of the CHRFAM7A c.497-498delTG polymorphism was determined in each group using heteroduplex analysis. An association between the c.497-498delTG polymorphism of CHRFAM7A and IGE was evidenced. It was demonstrated that the frequency of the CHRFAM7A 2-bp deletion carriers was significantly lower in the IGE patients than in the control group. The observed frequency of 2-bp deletion carriers was high in IGE subjects (64%), but significantly higher in control subjects (76%). Carriers of at least one copy of the -2 bp allele had halved their risk of IGE susceptibility (delTG/delTG and delTG/wild-type versus wild-type/wild-type: odds ratio=0.55; 95% confidence intervals=0.365-0.827; p=0.004). Moreover, it has been demonstrated that this polymorphic variant is associated with the c.524-12_524-11insGTT variation (rs10649395) in intron 7 of CHRFAM7A. Our study substantiates the involvement of the α7 subunit of nAChR in the pathophysiology of IGEs and indicates that the CHRFAM7A c.497-498TG deletion or a nearby polymorphism may play a role in the pathogenesis of IGE. Further work should concentrate on ascertaining the exact mechanism of this polymorphism's effect and its relationship with IGE.
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Affiliation(s)
- Agata Rozycka
- 1 Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences , Poznan, Poland
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22
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Herzog MH, Roinishvili M, Chkonia E, Brand A. Schizophrenia and visual backward masking: a general deficit of target enhancement. Front Psychol 2013; 4:254. [PMID: 23717290 PMCID: PMC3653113 DOI: 10.3389/fpsyg.2013.00254] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/16/2013] [Indexed: 02/04/2023] Open
Abstract
The obvious symptoms of schizophrenia are of cognitive and psychopathological nature. However, schizophrenia affects also visual processing which becomes particularly evident when stimuli are presented for short durations and are followed by a masking stimulus. Visual deficits are of great interest because they might be related to the genetic variations underlying the disease (endophenotype concept). Visual masking deficits are usually attributed to specific dysfunctions of the visual system such as a hypo- or hyper-active magnocellular system. Here, we propose that visual deficits are a manifestation of a general deficit related to the enhancement of weak neural signals as occurring in all other sorts of information processing. We summarize previous findings with the shine-through masking paradigm where a shortly presented vernier target is followed by a masking grating. The mask deteriorates visual processing of schizophrenic patients by almost an order of magnitude compared to healthy controls. We propose that these deficits are caused by dysfunctions of attention and the cholinergic system leading to weak neural activity corresponding to the vernier. High density electrophysiological recordings (EEG) show that indeed neural activity is strongly reduced in schizophrenic patients which we attribute to the lack of vernier enhancement. When only the masking grating is presented, EEG responses are roughly comparable between patients and control. Our hypothesis is supported by findings relating visual masking to genetic deviants of the nicotinic α7 receptor (CHRNA7).
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Affiliation(s)
- Michael H Herzog
- Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne Lausanne, Switzerland
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23
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Radek RJ, Robb HM, Stevens KE, Gopalakrishnan M, Bitner RS. Effects of the novel α7 nicotinic acetylcholine receptor agonist ABT-107 on sensory gating in DBA/2 mice: pharmacodynamic characterization. J Pharmacol Exp Ther 2012; 343:736-45. [PMID: 22988063 DOI: 10.1124/jpet.112.197970] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nicotinic acetylcholine receptor (nAChR) agonists improve sensory gating deficits in animal models and schizophrenic patients. The aim of this study was to determine whether the novel and selective α7 nAChR full agonist 5-(6-[(3R)-1-azabicyclo[2.2.2]oct-3-yloxy]pyridazin-3-yl)-1H-indole (ABT-107) improves sensory gating deficits in DBA/2 mice. Sensory gating was measured by recording hippocampal-evoked potential P20-N40 waves and determining gating test/conditioning (T/C) ratios in a paired auditory stimulus paradigm. ABT-107 at 0.1 μmol/kg (average plasma concentration of 1.1 ng/ml) significantly improved sensory gating by lowering T/C ratios during a 30-min period after administration in unanesthetized DBA/2 mice. ABT-107 at 1.0 μmol/kg was ineffective at 30 min after administration when average plasma levels were 13.5 ng/ml. However, the 1.0 μmol/kg dose was effective 180 min after administration when plasma concentration had fallen to 1.9 ng/ml. ABT-107 (0.1 μmol/kg) also improved sensory gating in anesthetized DBA/2 mice pretreated with α7 nAChR-desensitizing doses of nicotine (6.2 μmol/kg) or ABT-107 (0.1 μmol/kg) itself. Moreover, repeated b.i.d. dosing of ABT-107 (0.1 μmol/kg) was as efficacious as a single dose. The acute efficacy of ABT-107 (0.1 μmol/kg) was blocked by the nAChR antagonist methyllycaconitine, but not by the α4β2 nAChR antagonist dihydro-β-erythroidine. These studies demonstrate that ABT-107 improves sensory gating through the activation of nAChRs, and efficacy is sustained under conditions of repeated dosing or with prior nAChR activation with nicotine.
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Affiliation(s)
- Richard J Radek
- Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064, USA.
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Association between the 2-bp deletion polymorphism in the duplicated version of the alpha7 nicotinic receptor gene and P50 sensory gating. Eur J Hum Genet 2012; 21:76-81. [PMID: 22588665 DOI: 10.1038/ejhg.2012.81] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
There is considerable evidence implicating the 15q13.3 region in neuropsychiatric disorders, with the α7 nicotinic receptor gene CHRNA7 the most plausible candidate. This region has multiple duplications and many copy number variants (CNVs). A common CNV involves a partial duplication of CHRNA7 (CHRFAM7A), which occurs in either orientation. We examined the distribution of these alternative genomic arrangements in a large cohort of psychiatric patients, their relatives and controls using the 2-bp deletion polymorphism as a marker for the orientation of CHRFAM7A. We investigated three common alleles for association with psychosis and with the P50 sensory gating deficit, which is strongly associated with psychosis and strongly linked to 15q13.3. We found significant within-family association with P50 (empirical P=0.004), which is robust to population stratification. Most of the effect came from the 2-bp deletion allele, which tags the variant of CHRFAM7A in the same orientation as CHRNA7. This allele is associated with the presence of the P50 sensory gating deficit (empirical P=0.0006). Tests comparing within-family and between-family components of association suggest considerable population stratification in the sample. We found no evidence for association with psychosis, but this may reflect lower power using this phenotype. Four out of six previous association studies found association of different psychiatric phenotypes with the same 2-bp deletion allele.
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25
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Araud T, Graw S, Berger R, Lee M, Neveu E, Bertrand D, Leonard S. The chimeric gene CHRFAM7A, a partial duplication of the CHRNA7 gene, is a dominant negative regulator of α7*nAChR function. Biochem Pharmacol 2011; 82:904-14. [PMID: 21718690 PMCID: PMC3162115 DOI: 10.1016/j.bcp.2011.06.018] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 06/10/2011] [Accepted: 06/13/2011] [Indexed: 12/11/2022]
Abstract
The human α7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) is a candidate gene for schizophrenia and an important drug target for cognitive deficits in the disorder. Activation of the α7*nAChR, results in opening of the channel and entry of mono- and divalent cations, including Ca(2+), that presynaptically participates to neurotransmitter release and postsynaptically to down-stream changes in gene expression. Schizophrenic patients have low levels of α7*nAChR, as measured by binding of the ligand [(125)I]-α-bungarotoxin (I-BTX). The structure of the gene, CHRNA7, is complex. During evolution, CHRNA7 was partially duplicated as a chimeric gene (CHRFAM7A), which is expressed in the human brain and elsewhere in the body. The association between a 2bp deletion in CHRFAM7A and schizophrenia suggested that this duplicate gene might contribute to cognitive impairment. To examine the putative contribution of CHRFAM7A on receptor function, co-expression of α7 and the duplicate genes was carried out in cell lines and Xenopus oocytes. Expression of the duplicate alone yielded protein expression but no functional receptor and co-expression with α7 caused a significant reduction of the amplitude of the ACh-evoked currents. Reduced current amplitude was not correlated with a reduction of I-BTX binding, suggesting the presence of non-functional (ACh-silent) receptors. This hypothesis is supported by a larger increase of the ACh-evoked current by the allosteric modulator 1-(5-chloro-2,4-dimethoxy-phenyl)-3-(5-methyl-isoxazol-3-yl)-urea (PNU-120596) in cells expressing the duplicate than in the control. These results suggest that CHRFAM7A acts as a dominant negative modulator of CHRNA7 function and is critical for receptor regulation in humans.
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Affiliation(s)
- Tanguy Araud
- Department of Neurosciences Medical Faculty, University of Geneva, Geneva, Switzerland.
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26
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Evidence for association of the non-duplicated region of CHRNA7 gene with bipolar disorder but not with Schizophrenia. Psychiatr Genet 2011; 20:289-97. [PMID: 20463630 DOI: 10.1097/ypg.0b013e32833a9b7a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Biological evidence in both human and animal studies suggests α7 neuronal nicotinic acetylcholine receptor subunit gene (CHRNA7) as a suitable functional candidate for genetic studies in psychiatric populations. This gene maps to chromosome 15q13-14, a major linkage hotspot for schizophrenia (SCH) and bipolar disorder (BD). In this study we examine the role of CHRNA7 in influencing the risk of SCH and BD. METHODS In the present investigation four SNPs of the non-duplicated region of CHRNA7 were genotyped: -86C/T variant, located in the 5'-upstream regulatory region; and three intronic polymorphisms (rs883473, rs6494223 and rs904952). Genetic analysis was performed on 510 patients diagnosed with SCH, 245 with BD and on 793 unrelated healthy controls. RESULTS SNP analysis suggested a significant difference in -86C/T allele (P=0.025) and genotype (P=0.03) frequencies between BD and control groups, although significance was lost after correction for multiple testing. Besides, the nucleotide change (T) in rs6494223 had a protective effect against BD [odds ratio (OR)=0.70 (0.57-0.87); P=0.001]. Genotype frequencies also showed significant association (P=0.001) [CT genotype OR=0.71 (0.5-0.96); TT genotype OR=0.47 (0.29-0.77)]. Haplotypic analysis revealed a positive association of the gene with BD (global-stat=24.18, P value=0.007) with a maximum effect in the region that covered introns 3 and 4. In contrast, no evidence of risk variants was found in the analysis of the SCH sample. CONCLUSION Our data support the non-duplicated region of CHRNA7 gene as a susceptibility region for BD but not for SCH. Further genotyping of this region may help to delimit the causal polymorphism.
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Cooper DN, Kehrer-Sawatzki H. Exploring the potential relevance of human-specific genes to complex disease. Hum Genomics 2011; 5:99-107. [PMID: 21296743 PMCID: PMC3525227 DOI: 10.1186/1479-7364-5-2-99] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Although human disease genes generally tend to be evolutionarily more ancient than non-disease genes, complex disease genes appear to be represented more frequently than Mendelian disease genes among genes of more recent evolutionary origin. It is therefore proposed that the analysis of human-specific genes might provide new insights into the genetics of complex disease. Cross-comparison with the Human Gene Mutation Database (http://www.hgmd.org) revealed a number of examples of disease-causing and disease-associated mutations in putatively human-specific genes. A sizeable proportion of these were missense polymorphisms associated with complex disease. Since both human-specific genes and genes associated with complex disease have often experienced particularly rapid rates of evolutionary change, either due to weaker purifying selection or positive selection, it is proposed that a significant number of human-specific genes may play a role in complex disease.
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Affiliation(s)
- David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK.
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28
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de Lucas-Cerrillo AM, Maldifassi MC, Arnalich F, Renart J, Atienza G, Serantes R, Cruces J, Sánchez-Pacheco A, Andrés-Mateos E, Montiel C. Function of partially duplicated human α77 nicotinic receptor subunit CHRFAM7A gene: potential implications for the cholinergic anti-inflammatory response. J Biol Chem 2010; 286:594-606. [PMID: 21047781 DOI: 10.1074/jbc.m110.180067] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The neuronal α7 nicotinic receptor subunit gene (CHRNA7) is partially duplicated in the human genome forming a hybrid gene (CHRFAM7A) with the novel FAM7A gene. The hybrid gene transcript, dupα7, has been identified in brain, immune cells, and the HL-60 cell line, although its translation and function are still unknown. In this study, dupα7 cDNA has been cloned and expressed in GH4C1 cells and Xenopus oocytes to study the pattern and functional role of the expressed protein. Our results reveal that dupα7 transcript was natively translated in HL-60 cells and heterologously expressed in GH4C1 cells and oocytes. Injection of dupα7 mRNA into oocytes failed to generate functional receptors, but when co-injected with α7 mRNA at α7/dupα7 ratios of 5:1, 2:1, 1:1, 1:5, and 1:10, it reduced the nicotine-elicited α7 current generated in control oocytes (α7 alone) by 26, 53, 75, 93, and 94%, respectively. This effect is mainly due to a reduction in the number of functional α7 receptors reaching the oocyte membrane, as deduced from α-bungarotoxin binding and fluorescent confocal assays. Two additional findings open the possibility that the dominant negative effect of dupα7 on α7 receptor activity observed in vitro could be extrapolated to in vivo situations. (i) Compared with α7 mRNA, basal dupα7 mRNA levels are substantial in human cerebral cortex and higher in macrophages. (ii) dupα7 mRNA levels in macrophages are down-regulated by IL-1β, LPS, and nicotine. Thus, dupα7 could modulate α7 receptor-mediated synaptic transmission and cholinergic anti-inflammatory response.
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29
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Joo EJ, Lee KY, Kim HS, Kim SH, Ahn YM, Kim YS. Genetic Association Study of the Alpha 7 Nicotinic Receptor (CHRNA7) with the Development of Schizophrenia and Bipolar Disorder in Korean Population. Psychiatry Investig 2010; 7:196-201. [PMID: 20927308 PMCID: PMC2947807 DOI: 10.4306/pi.2010.7.3.196] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 06/06/2010] [Accepted: 07/04/2010] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVE CHRNA7 has been shown to be a strong candidate gene for schizophrenia and bipolar disorder. It is located on chromosome 15q13-q14, which is one of the replicated linkage spots for schizophrenia and bipolar disorder. METHODS We conducted an association study to determine whether previous positive association is replicable in the Korean population. We included 254 patients with schizophrenia, 193 patients with bipolar disorder type I, 38 patients with bipolar disorder type II, 64 schizoaffective disorder patients, and 349 controls. All subjects were ethnically Korean. A total of 898 subjects were included, and genotyping was done for three single nucleotide polymorphisms (SNPs) of CHRNA7. These three intronic SNPs were rs2337506 (A/G), rs6494223 (C/T), and rs12916879 (A/G). RESULTS There was only one marginally significant association; this association was between rs12916879 and bipolar disorder type I in the male subgroup. In both the allele and genotype distributions, we found a weak signal (Chi-squared=3.57, df=1, p=0.06 for allele, Chi-squared=7.50, df=2, p=0.02 for genotype) only. Unphased haplotype analysis could not provide additional support for this finding. No SNP was associated with schizophrenia or any other affected groups in this Korean sample. The associative finding is marginal and inconclusive. CONCLUSION We could not replicate positive association in other ethnic groups previously studied. This suggests possible heterogeneity in the genes associated with schizophrenia and bipolar disorders. Because of structural complexity of the CHRNA7 gene and the limited statistical power of this study, further genetic studies with more SNPs and larger samples covering various populations, along with more fine molecular exploration of the CHRNA7 gene structure, are required.
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Affiliation(s)
- Eun-Jeong Joo
- Department of Neuropsychiatry, Eulji University School of Medicine, Eulji General Hospital, Seoul, Korea
| | - Kyu Young Lee
- Department of Neuropsychiatry, Eulji University School of Medicine, Eulji General Hospital, Seoul, Korea
| | - Hyun Sook Kim
- College of Nursing, Eulji University, Seongnam, Korea
| | - Se Hyun Kim
- Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, Seoul, Korea
- Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Yong Min Ahn
- Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, Seoul, Korea
| | - Yong Sik Kim
- Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, Seoul, Korea
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30
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Knott VJ, Fisher DJ, Millar AM. Differential effects of nicotine on P50 amplitude, its gating, and their neural sources in low and high suppressors. Neuroscience 2010; 170:816-26. [PMID: 20643194 DOI: 10.1016/j.neuroscience.2010.07.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 07/05/2010] [Accepted: 07/06/2010] [Indexed: 10/19/2022]
Abstract
Sensory gating impairment in schizophrenia has been documented in the form of aberrant middle latency P50 event-related brain potential responses to S(1) and/or S(2) stimuli in a paired (S(1)-S(2)) auditory stimulus paradigm. Evidenced by a failure to suppress S(2) P50 or by attenuated S(1) P50s, these sensory deficits have been associated with increased smoking behaviour in this disorder, and may be related to the putative ameliorating effects of smoke-inhaled nicotine on neural mechanisms regulating gating. Comparison of healthy controls with low versus high gating efficiency has been forwarded as a model for investigating the actions of antipsychotic agents on aberrant gating functions. In the current study, the effect of a single dose (6 mg) of nicotine gum on P50, gating indices, and their cortical sources indexed with sLORETA (standardized low resolution electromagnetic tomography), was examined in healthy non-smokers (n=24) stratified for low and high gating levels. Scalp surface recordings revealed nicotine modulation of P50 and its gating to be differentially exhibited in high (decreasing gating) and low (increasing gating) suppressors while the underlying cortical sources influenced by nicotine (middle frontal gyrus, inferior/superior parietal lobules, pre- and post-central gyri) were seen only in low suppressors. These findings suggest that nicotine impacts sensory gating in healthy volunteers and as the gating enhancing effects were dependent on low baseline gating efficiency, nicotinic receptor agonists may be associated with unique P50 modulating actions in schizophrenia.
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Affiliation(s)
- V J Knott
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.
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Abstract
Cigarette smoking is the main preventable cause of death in developed countries, and the development of more effective treatments is necessary. Cumulating evidence suggests that cognitive enhancement may contribute to the addictive actions of nicotine. Several studies have demonstrated that nicotine enhances cognitive performance in both smokers and non-smokers. Genetic studies support the role of both dopamine (DA) and nicotinic acetylcholine receptors (nAChRs) associated with nicotine-induced cognitive enhancement. Based on knockout mice studies, beta2 nAChRs are thought to be essential in mediating the cognitive effects of nicotine. alpha7nAChRs are associated with attentional and sensory filtering response, especially in schizophrenic individuals. Genetic variation in D2 type DA receptors and the catechol-O-methyltransferase enzyme appears to moderate cognitive deficits induced by smoking abstinence. Serotonin transporter (5-HTT) gene variation also moderates nicotine-induced improvement in spatial working memory. Less is known about the contribution of genetic variation in DA transporter and D4 type DA receptor genetic variation on the cognitive effects of nicotine. Future research will provide a clearer understanding of the mechanism underlying the cognitive-enhancing actions of nicotine.
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Affiliation(s)
- Aryeh I Herman
- Department of Psychiatry and VA Connecticut Healthcare System, School of Medicine, Yale University, West Haven, CT 06516, USA
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32
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Knott V, Millar A, Fisher D, Albert P. Effects of nicotine on the amplitude and gating of the auditory P50 and its influence by dopamine D2 receptor gene polymorphism. Neuroscience 2010; 166:145-56. [DOI: 10.1016/j.neuroscience.2009.11.053] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 11/11/2009] [Accepted: 11/19/2009] [Indexed: 11/16/2022]
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Freedman R, Goldowitz D. Studies on the hippocampal formation: From basic development to clinical applications: Studies on schizophrenia. Prog Neurobiol 2009; 90:263-75. [PMID: 19853005 DOI: 10.1016/j.pneurobio.2009.10.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 07/31/2009] [Accepted: 10/09/2009] [Indexed: 10/20/2022]
Abstract
The hippocampal formation plays a critical role in cognitive function. The developmental events that shape the hippocampal formation are continuing to be elucidated and their implications for brain function are emerging as well as applying those advances to interventions that have important possibilities for the treatment of brain dysfunction. The story told in this chapter is about the use of the in oculo transplant method to illuminate intrinsic and extrinsic features that underlie the development of the dentate gyrus and adjacent hippocampus and the role of one molecule in the hippocampus and schizophrenia. Schizophrenia, originally conceptualized as a dysfunction in dopaminergic neurotransmission, is now known to involve multiple neuronal systems. Dysfunction of hippocampal neurons is emerging as one of its signature pathological features. Basic insights into the development and function of hippocampal interneurons form the basis of a new treatment initiative for this illness. Evidence for the role of the alpha 7-nicotinic acetylcholine receptor in the development and function of these neurons in rodents has led to human trials of nicotinic agonists for cognitive dysfunction in schizophrenia and the possibility of improving hippocampal development in children at risk for schizophrenia by perinatal supplementation with choline, which can act as an alpha 7-nicotinic acetylcholine receptor agonist.
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Affiliation(s)
- Robert Freedman
- Dept Psychiatry, University of Colorado at Denver and Health Sciences Center, 13001 E. 17th Pl., Campus Box F546, Aurora, CO 800045, USA
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Sinkus ML, Lee MJ, Gault J, Logel J, Short M, Freedman R, Christian SL, Lyon J, Leonard S. A 2-base pair deletion polymorphism in the partial duplication of the alpha7 nicotinic acetylcholine gene (CHRFAM7A) on chromosome 15q14 is associated with schizophrenia. Brain Res 2009; 1291:1-11. [PMID: 19631623 DOI: 10.1016/j.brainres.2009.07.041] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 07/13/2009] [Accepted: 07/14/2009] [Indexed: 11/27/2022]
Abstract
Multiple genetic linkage studies support the hypothesis that the 15q13-14 chromosomal region contributes to the etiology of schizophrenia. Among the putative candidate genes in this area are the alpha7 nicotinic acetylcholine receptor gene (CHRNA7) and its partial duplication, CHRFAM7A. A large chromosomal segment including the CHRFAM7A gene locus, but not the CHRNA7 locus, is deleted in some individuals. The CHRFAM7A gene contains a polymorphism consisting of a 2 base pair (2 bp) deletion at position 497-498 bp of exon 6. We employed PCR-based methods to quantify the copy number of CHRFAM7A and the presence of the 2 bp polymorphism in a large, multi-ethnic population. The 2 bp polymorphism was associated with schizophrenia in African Americans (genotype p=0.005, allele p=0.015), and in Caucasians (genotype p=0.015, allele p=0.009). We conclude that the presence of the 2 bp polymorphism at the CHRFAM7A locus may have a functional significance in schizophrenia.
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Affiliation(s)
- Melissa L Sinkus
- Department of Psychiatry, University of Colorado at Denver, Denver, CO 80045, USA
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Bunnelle WH, Tietje KR, Frost JM, Peters D, Ji J, Li T, Scanio MJC, Shi L, Anderson DJ, Dyhring T, Grønlien JH, Ween H, Thorin-Hagene K, Meyer MD. Octahydropyrrolo[3,4-c]pyrrole: A Diamine Scaffold for Construction of Either α4β2 or α7-Selective Nicotinic Acetylcholine Receptor (nAChR) Ligands. Substitutions that Switch Subtype Selectivity. J Med Chem 2009; 52:4126-41. [DOI: 10.1021/jm900249k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- William H. Bunnelle
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Karin R. Tietje
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Jennifer M. Frost
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Dan Peters
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Jianguo Ji
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Tao Li
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Marc J. C. Scanio
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Lei Shi
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - David J. Anderson
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Tino Dyhring
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Jens H. Grønlien
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Hilde Ween
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Kirsten Thorin-Hagene
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
| | - Michael D. Meyer
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117
- NeuroSearch A/S, 93 Pederstrupvej, DK-2750 Ballerup, Denmark
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Abstract
Chromosome 15q13-q14 harbours the gene for the alpha7 nicotinic acetylcholine receptor subunit (CHRNA7) and a related gene (CHRFAM7A) which arises from a partly duplicated portion of CHRNA7. Recent evidence suggests that CHRFAM7A is a locus with a possible role in schizophrenia and cognitive functioning. We studied an antisaccade task as a fronto-parietal measure of executive function that reflects risk for schizophrenia. Association of CHRFAM7A genotype with antisaccade performance was assessed in 103 healthy Caucasian individuals. No significant associations of 2-bp deletion or CHRFAM7A copy number with antisaccade performance parameters were observed. The failure to observe an association between antisaccade performance and polymorphisms in CHRFAM7A gene is consistent with specificity of the gene effects on hippocampal and memory functions as previously demonstrated.
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Severance EG, Dickerson FB, Stallings CR, Origoni AE, Sullens A, Monson ET, Yolken RH. Differentiating nicotine- versus schizophrenia-associated decreases of the alpha7 nicotinic acetylcholine receptor transcript, CHRFAM7A, in peripheral blood lymphocytes. J Neural Transm (Vienna) 2008; 116:213-20. [PMID: 19082523 DOI: 10.1007/s00702-008-0164-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
Abstract
Nicotine addiction is prevalent in individuals with schizophrenia. Nicotine activation of nicotinic receptors (nAChRs) is time- and dose-dependent, but gene expression analyses often rely on qualitative self- or family-reported measures of smoking. We sought lymphocyte surrogates for cerebral alpha7-nAChR activity and tested if receptor transcription correlated with concurrently measured serum biomarkers for smoking [cotinine, C-reactive protein (CRP)]. PCR surveys to detect lymphocytic alpha7-related isoforms identified CHRFAM7A as the only consistently amplifiable transcript. In 20 smoking-matched people (n = 10 schizophrenia, n = 10 controls), we found significantly lower CHRFAM7A in cotinine and self-reported smokers versus nonsmokers (p <or= 0.001-0.03) and an inverse correlation of cotinine with CHRFAM7A (p <or= 0.04) in regression models. CHRFAM7A was not associated with diagnosis or CRP in any bi- or multi-variate analysis. Smoking-related CRP elevations only occurred in cotinine-based comparisons (p <or= 0.03), and not when smoking was self-reported. Including biochemical indicators of serum nicotine can help differentiate smoking- versus disease-associated changes in nAChR expression.
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Affiliation(s)
- Emily G Severance
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287-4933, USA.
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Feuerbach D, Lingenhoehl K, Olpe HR, Vassout A, Gentsch C, Chaperon F, Nozulak J, Enz A, Bilbe G, McAllister K, Hoyer D. The selective nicotinic acetylcholine receptor alpha7 agonist JN403 is active in animal models of cognition, sensory gating, epilepsy and pain. Neuropharmacology 2008; 56:254-63. [PMID: 18793655 DOI: 10.1016/j.neuropharm.2008.08.025] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 08/01/2008] [Accepted: 08/11/2008] [Indexed: 11/25/2022]
Abstract
Several lines of evidence suggest that the nicotinic acetylcholine receptor alpha7 (nAChR alpha7) is involved in central nervous system disorders like schizophrenia and Alzheimer's disease as well as in inflammatory disorders like sepsis and pancreatitis. The present article describes the in vivo effects of JN403, a compound recently characterized to be a potent and selective partial nAChR alpha7 agonist. JN403 rapidly penetrates into the brain after i.v. and after p.o. administration in mice and rats. In the social recognition test in mice JN403 facilitates learning/memory performance over a broad dose range. JN403 shows anxiolytic-like properties in the social exploration model in rats and the effects are retained after a 6h pre-treatment period and after subchronic administration. The effect on sensory inhibition was investigated in DBA/2 mice, a strain with reduced sensory inhibition under standard experimental conditions. Systemic administration of JN403 restores sensory gating in DBA/2 mice, both in anaesthetized and awake animals. Furthermore, JN403 shows anticonvulsant potential in the audiogenic seizure paradigm in DBA/2 mice. In the two models of permanent pain tested, JN403 produces a significant reversal of mechanical hyperalgesia. The onset was fast and the duration lasted for about 6h. Altogether, the present set of data suggests that nAChR alpha7 agonists, like JN403 may be beneficial for improving learning/memory performance, restoring sensory gating deficits, and alleviating pain, epileptic seizures and conditions of anxiety.
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Affiliation(s)
- Dominik Feuerbach
- Novartis Institutes for BioMedical Research, WSJ386.725, 4002 Basel, Switzerland.
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39
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Genetic Variation in the α7 Nicotinic Acetylcholine Receptor is Associated with Delusional Symptoms in Alzheimer’s Disease. Neuromolecular Med 2008; 10:377-84. [DOI: 10.1007/s12017-008-8048-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Accepted: 07/30/2008] [Indexed: 10/21/2022]
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40
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Steinlein OK, Bertrand D. Neuronal nicotinic acetylcholine receptors: from the genetic analysis to neurological diseases. Biochem Pharmacol 2008; 76:1175-83. [PMID: 18691557 DOI: 10.1016/j.bcp.2008.07.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 07/09/2008] [Accepted: 07/09/2008] [Indexed: 10/21/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated channels that mediate, in the peripheral nervous system, fast neurotransmission at the neuromuscular junction and in ganglia. Widely expressed in the central nervous system neuronal nAChRs are thought to contribute both to neurotransmission and modulation of neuronal activity. To date, eleven genes encoding for these receptors have been identified in the mammalian genome and their structure is well conserved throughout evolution. Progresses made in the field of genetics and the identification of a large number of small genetic variants such as single nucleotide polymorphisms raise new questions about the physiologic and pharmacologic consequences of such variations. The finding of associations between polymorphisms in the genes encoding for the neuronal nAChRs and neurological disorders such as schizophrenia and Alzheimer disease illustrate the importance of getting a better understanding of these receptors from the gene to function. In this work we present an overview over the progress that has been made in understanding the role of nAChR genes in monogenic disorders such as familial epilepsy, and review the latest knowledge about genetic variants of the nAChR genes and their relationship with common disorders and behavioural traits of complex etiology.
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Affiliation(s)
- O K Steinlein
- Institute of Human Genetics, University Hospital, Ludwig Maximilians University, Munich, Germany
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41
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Flomen RH, Davies AF, Di Forti M, Cascia CL, Mackie-Ogilvie C, Murray R, Makoff AJ. The copy number variant involving part of the α7 nicotinic receptor gene contains a polymorphic inversion. Eur J Hum Genet 2008; 16:1364-71. [DOI: 10.1038/ejhg.2008.112] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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42
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Sánchez-Morla EM, García-Jiménez MA, Barabash A, Martínez-Vizcaíno V, Mena J, Cabranes-Díaz JA, Baca-Baldomero E, Santos JL. P50 sensory gating deficit is a common marker of vulnerability to bipolar disorder and schizophrenia. Acta Psychiatr Scand 2008; 117:313-8. [PMID: 18241306 DOI: 10.1111/j.1600-0447.2007.01141.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE P50 gating in schizophrenia has contributed much to our understanding of the pathophysiology of the illness. We examined euthymic bipolar patients to determine if they also have a P50 gating deficit. METHOD P50 gating was measured in 81 euthymic bipolar patients (50 with a lifetime history of psychotic symptoms), 92 stable schizophrenic patients, and 67 control subjects. RESULTS P50 gating was significantly lower in control subjects than in bipolar patients with a lifetime history of psychosis (P = 0.001) and schizophrenic patients (P = 0.0001). In all patient groups, the percentage of patients with P50 gating was higher than in the control group (chi(2) = 30.596; P < 0.0001). There was no statistically significant correlation between P50 gating and other clinical variables. CONCLUSION Our data suggest that P50 gating deficit is a neurobiological marker that is present in stable schizophrenic patients and euthymic bipolar patients.
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Affiliation(s)
- E M Sánchez-Morla
- Department of Psychiatry, Hospital General Universitario de Guadalajara, Guadalajara, Spain.
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43
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Tietje KR, Anderson DJ, Bitner RS, Blomme EA, Brackemeyer PJ, Briggs CA, Browman KE, Bury D, Curzon P, Drescher KU, Frost JM, Fryer RM, Fox GB, Gronlien JH, Håkerud M, Gubbins EJ, Halm S, Harris R, Helfrich RJ, Kohlhaas KL, Law D, Malysz J, Marsh KC, Martin RL, Meyer MD, Molesky AL, Nikkel AL, Otte S, Pan L, Puttfarcken PS, Radek RJ, Robb HM, Spies E, Thorin-Hagene K, Waring JF, Ween H, Xu H, Gopalakrishnan M, Bunnelle WH. Preclinical Characterization of A-582941: A Novel α7 Neuronal Nicotinic Receptor Agonist with Broad Spectrum Cognition-Enhancing Properties. CNS Neurosci Ther 2008. [DOI: 10.1111/j.1755-5949.2008.00037.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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44
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Hashimoto T, Shimizu E, Koike K, Orita Y, Suzuki T, Kanahara N, Matsuzawa D, Fukami G, Miyatake R, Shinoda N, Fujisaki M, Shirayama Y, Hashimoto K, Iyo M. Deficits in auditory P50 inhibition in obsessive-compulsive disorder. Prog Neuropsychopharmacol Biol Psychiatry 2008; 32:288-96. [PMID: 17884267 DOI: 10.1016/j.pnpbp.2007.08.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Revised: 08/20/2007] [Accepted: 08/20/2007] [Indexed: 01/15/2023]
Abstract
Obsessive-compulsive disorder (OCD) is considered to involve abnormalities in inhibitory processes including gating systems. Auditory P50 inhibition, which is assessed by using a paired auditory stimulus paradigm to record P50 mid-latency evoked potential, is assumed to reflect sensory gating. In the present study, we investigated auditory P50 inhibition in subjects with OCD, and examined the relationship between P50 and clinical variables or neuropsychological performance. Twenty-six subjects with OCD and 26 age- and sex-matched healthy controls received P50 recording and neuropsychological tests. In the OCD subjects, we also evaluated clinical features including OC symptoms and subtypes of the disorder. P50 T/C ratios were significantly higher in OCD subjects than in control subjects (t=2.9, df=50, p=0.006). Compared to the controls, the OCD subjects performed significantly worse on the Symbol Digit Modalities Test (SDMT) and the Trail Making Test (TMT). There were no correlations between P50 T/C ratios and clinical variables or the results of neuropsychological tests. Our findings suggest that sensory gating deficits may be involved in the pathophysiology of OCD in a different way from clinical symptoms and executive attention dysfunction.
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Affiliation(s)
- Tasuku Hashimoto
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan
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45
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Tietje KR, Anderson DJ, Bitner RS, Blomme EA, Brackemeyer PJ, Briggs CA, Browman KE, Bury D, Curzon P, Drescher KU, Frost JM, Fryer RM, Fox GB, Gronlien JH, Håkerud M, Gubbins EJ, Halm S, Harris R, Helfrich RJ, Kohlhaas KL, Law D, Malysz J, Marsh KC, Martin RL, Meyer MD, Molesky AL, Nikkel AL, Otte S, Pan L, Puttfarcken PS, Radek RJ, Robb HM, Spies E, Thorin‐Hagene K, Waring JF, Ween H, Xu H, Gopalakrishnan M, Bunnelle WH. Preclinical characterization of A-582941: a novel alpha7 neuronal nicotinic receptor agonist with broad spectrum cognition-enhancing properties. CNS Neurosci Ther 2008; 14:65-82. [PMID: 18482100 PMCID: PMC6494002 DOI: 10.1111/j.1527-3458.2008.00037.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Among the diverse sets of nicotinic acetylcholine receptors (nAChRs), the alpha7 subtype is highly expressed in the hippocampus and cortex and is thought to play important roles in a variety of cognitive processes. In this review, we describe the properties of a novel biaryl diamine alpha7 nAChR agonist, A-582941. A-582941 was found to exhibit high-affinity binding and partial agonism at alpha7 nAChRs, with acceptable pharmacokinetic properties and excellent distribution to the central nervous system (CNS). In vitro and in vivo studies indicated that A-582941 activates signaling pathways known to be involved in cognitive function such as ERK1/2 and CREB phosphorylation. A-582941 enhanced cognitive performance in behavioral models that capture domains of working memory, short-term recognition memory, memory consolidation, and sensory gating deficit. A-582941 exhibited a benign secondary pharmacodynamic and tolerability profile as assessed in a battery of assays of cardiovascular, gastrointestinal, and CNS function. The studies summarized in this review collectively provide preclinical validation that alpha7 nAChR agonism offers a mechanism with potential to improve cognitive deficits associated with various neurodegenerative and psychiatric disorders.
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Affiliation(s)
- Karin R. Tietje
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - David J. Anderson
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - R. Scott Bitner
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Eric A. Blomme
- Department of Cellular and Molecular Toxicology, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Paul J. Brackemeyer
- Manufacturing Science and Technology, Global Pharmaceutical Operations, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Clark A. Briggs
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Kaitlin E. Browman
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Dagmar Bury
- Toxicology & Pathology, Global Pharmaceutical Research and Development, Abbott Laboratories, Ludwigshafen, Germany
| | - Peter Curzon
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Karla U. Drescher
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Ludwigshafen, Germany
| | - Jennifer M. Frost
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Ryan M. Fryer
- Department of Integrative Pharmacology, Global Pharmaceutical Research & Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Gerard B. Fox
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Jens Halvard Gronlien
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Monika Håkerud
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Earl J. Gubbins
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Sabine Halm
- Toxicology & Pathology, Global Pharmaceutical Research and Development, Abbott Laboratories, Ludwigshafen, Germany
| | - Richard Harris
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Rosalind J. Helfrich
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Kathy L. Kohlhaas
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Devalina Law
- Manufacturing Science and Technology, Global Pharmaceutical Operations, Abbott Laboratories, Abbott Park, Illinois, USA
| | - John Malysz
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Kennan C. Marsh
- Pharmacokinetics and Metabolism, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Ilinois, USA
| | - Ruth L. Martin
- Department of Integrative Pharmacology, Global Pharmaceutical Research & Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Michael D. Meyer
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Angela L. Molesky
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Arthur L. Nikkel
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Stephani Otte
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Liping Pan
- Pharmacokinetics and Metabolism, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Ilinois, USA
| | - Pamela S. Puttfarcken
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Richard J. Radek
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Holly M. Robb
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Eva Spies
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Ludwigshafen, Germany
| | - Kirsten Thorin‐Hagene
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Jeffrey F. Waring
- Department of Cellular and Molecular Toxicology, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Hilde Ween
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - Hongyu Xu
- Pharmacokinetics and Metabolism, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Ilinois, USA
| | - Murali Gopalakrishnan
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
| | - William H. Bunnelle
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, USA
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Abstract
Schizophrenia is a common mental illness with a high prevalence of smoking. More than 80% of schizophrenics smoke compared to 25% of the general population. Both schizophrenia and tobacco use have strong genetic components, which may overlap. It has been suggested that smoking in schizophrenia may be a form of self-medication in an attempt to treat an underlying biological pathology. Smoking normalizes auditory evoked potential and eye tracking deficits in schizophrenia, as well as improving cognitive function. Nicotine acts through a family of nicotinic receptors with either high or low affinity for nicotine. The loci for several of these receptors have been genetically linked to both smoking and to schizophrenia. Smoking changes gene expression for more than 200 genes in human hippocampus, and differentially normalizes aberrant gene expression in schizophrenia. The α7* nicotinic receptor, linked to schizophrenia and smoking, has been implicated in sensory processing deficits and is important for cognition and protection from neurotoxicity. Nicotine, however, has multiple health risks and desensitizes the receptor. A Phase I trial of DMXB-A, an α7* agonist, shows improvement in both P50 gating and in cognition, suggesting that further development of nicotinic cholinergic drugs is a promising direction in schizophrenia research.
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Affiliation(s)
- Sherry Leonard
- Department of Psychiatry, University of Colorado at Denver
- Department of Pharmacology, University of Colorado at Denver
- Health Sciences Center, the Veterans Affairs Medical Research Service, Denver, Colorado
| | - Sharon Mexal
- The Institute for Behavioral Genetics, Boulder, Colorado
| | - Robert Freedman
- Department of Psychiatry, University of Colorado at Denver
- Department of Pharmacology, University of Colorado at Denver
- Health Sciences Center, the Veterans Affairs Medical Research Service, Denver, Colorado
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47
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Shi J, Hattori E, Zou H, Badner JA, Christian SL, Gershon ES, Liu C. No evidence for association between 19 cholinergic genes and bipolar disorder. Am J Med Genet B Neuropsychiatr Genet 2007; 144B:715-23. [PMID: 17373692 PMCID: PMC2576477 DOI: 10.1002/ajmg.b.30417] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cholinergic dysfunction has been proposed for the pathogenesis of bipolar disorder (BD), and we have therefore performed a systematic association study of cholinergic system genes in BD (including schizoaffective disorder bipolar type). We genotyped 93 single nucleotide polymorphisms (SNPs) in 19 genes (CHAT, CHRM1-5, CHRNA1-7, CHRNA9, CHRNA10, and CHRNB1-4) in two series of samples: the National Institute of Mental Health (NIMH) Genetics Initiative pedigrees with 474 samples from 152 families, and the Clinical Neurogenetics (CNG) pedigrees with 83 samples from 22 multiplex families. Sib-transmission/disequilibrium test (sib_TDT) analysis showed nominally significant transmission bias for four SNPs (CHRNA2: rs7017417, P = 0.024; CHRNA5: rs514743, P = 0.031; CHRNB1: rs2302762, P = 0.049; CHRNB4: rs1948, P = 0.031). Haploview analyses showed nominally significant transmission bias of several haplotypes in CHRNA2, CHRNA7, CHRNB1, and CHRNB4, respectively. However, none of these associations reached gene-wide significance after correction by permutation. Alcohol dependence (including alcohol abuse) was not a significant covariate in the present genetic association analysis. Thus, it is unlikely that these 19 cholinergic genes play a major role in the pre-disposition to BD in these pedigrees.
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Affiliation(s)
- Jiajun Shi
- Department of Psychiatry, The University of Chicago, Chicago, IL 60637, USA
| | - Eiji Hattori
- Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute (BSI), Wako, Saitama 351-0198, Japan
| | - Hongwei Zou
- Department of Psychiatry, The University of Chicago, Chicago, IL 60637, USA
| | - Judith A. Badner
- Department of Psychiatry, The University of Chicago, Chicago, IL 60637, USA
| | - Susan L. Christian
- Department of Psychiatry, The University of Chicago, Chicago, IL 60637, USA
| | - Elliot S. Gershon
- Department of Psychiatry, The University of Chicago, Chicago, IL 60637, USA
| | - Chunyu Liu
- Department of Psychiatry, The University of Chicago, Chicago, IL 60637, USA
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48
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49
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Abstract
The idea that some phenotypes bear a closer relationship to the biological processes that give rise to psychiatric illness than diagnostic categories has attracted considerable interest. Much effort has been devoted to finding such endophenotypes, partly because it is believed that the genetic basis of endophenotypes will be easier to analyse than that of psychiatric disease. This belief depends in part on the assumption that the effect sizes of genetic loci contributing to endophenotypes are larger than those contributing to disease susceptibility, hence increasing the chance that genetic linkage and association tests will detect them. We examine this assumption by applying meta-analytical techniques to genetic association studies of endophenotypes. We find that the genetic effect sizes of the loci examined to date are no larger than those reported for other phenotypes. A review of the genetic architecture of traits in model organisms also provides no support for the view that the effect sizes of loci contributing to phenotypes closer to the biological basis of disease is any larger than those contributing to disease itself. While endophenotype measures may afford greater reliability, it should not be assumed that they will also demonstrate simpler genetic architecture.
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Affiliation(s)
- JONATHAN FLINT
- Wellcome Trust Centre for Human Genetics, University of
Oxford, Oxford, UK
| | - MARCUS R. MUNAFÒ
- Department of Experimental Psychology, University of
Bristol, Bristol, UK
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50
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Turetsky BI, Calkins ME, Light GA, Olincy A, Radant AD, Swerdlow NR. Neurophysiological endophenotypes of schizophrenia: the viability of selected candidate measures. Schizophr Bull 2007; 33:69-94. [PMID: 17135482 PMCID: PMC2632291 DOI: 10.1093/schbul/sbl060] [Citation(s) in RCA: 410] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In an effort to reveal susceptibility genes, schizophrenia research has turned to the endophenotype strategy. Endophenotypes are characteristics that reflect the actions of genes predisposing an individual to a disorder, even in the absence of diagnosable pathology. Individual endophenotypes are presumably determined by fewer genes than the more complex phenotype of schizophrenia and would, therefore, reduce the complexity of genetic analyses. Unfortunately, despite there being rational criteria to define a viable endophenotype, the term is sometimes applied indiscriminately to characteristics that are deviant in affected individuals. Schizophrenia patients exhibit deficits in several neurophysiological measures of information processing that have been proposed as candidate endophenotypes. Successful processing of sensory inputs requires the ability to inhibit intrinsic responses to redundant stimuli and, reciprocally, to facilitate responses to less frequent salient stimuli. There is evidence to suggest that both these processes are "impaired" in schizophrenia. Measures of inhibitory failure include prepulse inhibition of the startle reflex, P50 auditory evoked potential suppression, and antisaccade eye movements. Measures of impaired deviance detection include mismatch negativity and the P300 event-related potential. The purpose of this review is to systematically evaluate the endophenotype candidacy of these key neurophysiological abilities. For each candidate, we describe typical experimental procedures, the current understanding of the underlying neurobiology, the nature of the abnormality in schizophrenia, the reliability, stability and heritability of the measure, and any reported gene associations. We conclude with a discussion of the few studies thus far that have employed a multivariate approach with these candidates.
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Affiliation(s)
- Bruce I Turetsky
- Department of Psychiatry, 10th floor, Gates Building, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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