1
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Andersson U, Tracey KJ. Vagus nerve SARS-CoV-2 infection and inflammatory reflex dysfunction: Is there a causal relationship? J Intern Med 2024; 295:91-102. [PMID: 38018736 DOI: 10.1111/joim.13746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Autonomic dysfunction is a clinical hallmark of infection caused by SARS-CoV-2, but the underlying mechanisms are unknown. The vagus nerve inflammatory reflex is an important, well-characterized mechanism for the reflexive suppression of cytokine storm, and its experimental or clinical impairment facilitates the onset and progression of hyperinflammation. Recent pathological evidence from COVID-19 victims reveals viral infection and inflammation in the vagus nerve and associated nuclei in the medulla oblongata. Although it has been suggested that vagus nerve inflammation in these patients mediates dysregulated respiration, whether it also contributes to dysfunction of the vagus nerve inflammatory reflex has not been addressed. Because lethality and tissue injury in acute COVID-19 are characterized by cytokine storm, it is plausible to consider evidence that impairment of the inflammatory reflex may contribute to overproduction of cytokines and resultant hyperinflammatory pathogenesis. Accordingly, here the authors discuss the inflammatory reflex, the consequences of its dysfunction in COVID-19, and whether there are opportunities for therapeutic intervention.
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Affiliation(s)
- Ulf Andersson
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Kevin J Tracey
- Feinstein Institutes for Medical Research, Northwell Health, Manhasset, New York, USA
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2
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Choueiry J, Blais CM, Shah D, Smith D, Fisher D, Labelle A, Knott V. An α7 nAChR approach for the baseline-dependent modulation of deviance detection in schizophrenia: A pilot study assessing the combined effect of CDP-choline and galantamine. J Psychopharmacol 2023; 37:381-395. [PMID: 36927273 PMCID: PMC10101183 DOI: 10.1177/02698811231158903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
BACKGROUND Cognitive operations including pre-attentive sensory processing are markedly impaired in patients with schizophrenia (SCZ) but evidence significant interindividual heterogeneity, which moderates treatment response with nicotinic acetylcholine receptor (nAChR) agonists. Previous studies in healthy volunteers have shown baseline-dependency effects of the α7 nAChR agonist cytidine 5'-diphosphocholine (CDP-choline) administered alone and in combination with a nicotinic allosteric modulator (galantamine) on auditory deviance detection measured with the mismatch negativity (MMN) event-related potential (ERP). AIM The objective of this pilot study was to assess the acute effect of this combined α7 nAChR-targeted treatment (CDP-choline/galantamine) on speech MMN in patients with SCZ (N = 24) stratified by baseline MMN responses into low, medium, and high baseline auditory deviance detection subgroups. METHODS Patients with a stable diagnosis of SCZ attended two randomized, double-blind, placebo-controlled and counter-balanced testing sessions where they received a placebo or a CDP-choline (500 mg) and galantamine (16 mg) treatment. MMN ERPs were recorded during the presentation of a fast multi-feature speech MMN paradigm including five speech deviants. Clinical measures were acquired before and after treatment administration. RESULTS While no main treatment effect was observed, CDP-choline/galantamine significantly increased MMN amplitudes to frequency, duration, and vowel speech deviants in low group individuals. Individuals with higher positive and negative symptom scale negative, general, and total scores expressed the greatest MMN amplitude improvement following CDP-choline/galantamine. CONCLUSIONS These baseline-dependent nicotinic effects on early auditory information processing warrant different dosage and repeated administration assessments in patients with low baseline deviance detection levels.
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Affiliation(s)
- Joëlle Choueiry
- Department of Neuroscience, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Crystal M Blais
- Institute of Cognitive Science, Carleton University, Ottawa, ON, Canada
| | - Dhrasti Shah
- School of Psychology, Faculty of Social Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Dylan Smith
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Derek Fisher
- Department of Psychology, Faculty of Social Sciences, Mount Saint Vincent University, Halifax, NS, Canada
| | - Alain Labelle
- The Royal Ottawa Mental Health Centre, Ottawa, ON, Canada
| | - Verner Knott
- Department of Neuroscience, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.,Institute of Cognitive Science, Carleton University, Ottawa, ON, Canada.,School of Psychology, Faculty of Social Sciences, University of Ottawa, Ottawa, ON, Canada.,The Royal Ottawa Mental Health Centre, Ottawa, ON, Canada
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3
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Kanniah G, Kumar R. A selective literature review exploring the role of the nicotinic system in schizophrenia. Gen Psychiatr 2023; 36:e100756. [PMID: 36937093 PMCID: PMC10016241 DOI: 10.1136/gpsych-2022-100756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/16/2023] [Indexed: 03/17/2023] Open
Abstract
Nicotine use is more prevalent in patients with psychiatric disorders, especially those diagnosed with psychotic illnesses. Previously, this higher prevalence has been partially attributed to the potential ameliorative effects of nicotine on symptom severity and cognitive impairment. Some healthcare professionals and patients perceive there is a beneficial effect of nicotine on mental health. Emerging data show that the harm associated with nicotine in the population of patients with mental health conditions outweighs any potential benefit. This paper will review the evidence surrounding the nicotinic system and schizophrenia, with a focus on any causality between nicotine and psychosis.
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Affiliation(s)
- Guna Kanniah
- Mental Health and Addictions Services, Waikato DHB, Waikato Hospital, Hamilton, New Zealand
| | - Rishi Kumar
- Department of General Medicine, Middlemore Hospital, Auckland, New Zealand
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4
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Borroni V, Barrantes FJ. Homomeric and Heteromeric α7 Nicotinic Acetylcholine Receptors in Health and Some Central Nervous System Diseases. MEMBRANES 2021; 11:membranes11090664. [PMID: 34564481 PMCID: PMC8465519 DOI: 10.3390/membranes11090664] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/22/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels involved in the modulation of essential brain functions such as memory, learning, and attention. Homomeric α7 nAChR, formed exclusively by five identical α7 subunits, is involved in rapid synaptic transmission, whereas the heteromeric oligomers composed of α7 in combination with β subunits display metabotropic properties and operate in slower time frames. At the cellular level, the activation of nAChRs allows the entry of Na+ and Ca2+; the two cations depolarize the membrane and trigger diverse cellular signals, depending on the type of nAChR pentamer and neurons involved, the location of the intervening cells, and the networks of which these neuronal cells form part. These features make the α7 nAChR a central player in neurotransmission, metabolically associated Ca2+-mediated signaling, and modulation of diverse fundamental processes operated by other neurotransmitters in the brain. Due to its ubiquitous distribution and the multiple functions it displays in the brain, the α7 nAChR is associated with a variety of neurological and neuropsychiatric disorders whose exact etiopathogenic mechanisms are still elusive.
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Affiliation(s)
- Virginia Borroni
- Instituto de Tecnología en Polímeros y Nanotecnología (ITPN-UBA-CONICET), Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires C1127AAR, Argentina;
| | - Francisco J. Barrantes
- Laboratory of Molecular Neurobiology, Institute for Biomedical Research, UCA–CONICET, Faculty of Medical Sciences, Catholic University of Argentina, Av. Alicia Moreau de Justo 1600, Buenos Aires C1107AAZ, Argentina
- Correspondence:
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5
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Caton M, Ochoa ELM, Barrantes FJ. The role of nicotinic cholinergic neurotransmission in delusional thinking. NPJ SCHIZOPHRENIA 2020; 6:16. [PMID: 32532978 PMCID: PMC7293341 DOI: 10.1038/s41537-020-0105-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 05/15/2020] [Indexed: 02/07/2023]
Abstract
Delusions are a difficult-to-treat and intellectually fascinating aspect of many psychiatric illnesses. Although scientific progress on this complex topic has been challenging, some recent advances focus on dysfunction in neural circuits, specifically in those involving dopaminergic and glutamatergic neurotransmission. Here we review the role of cholinergic neurotransmission in delusions, with a focus on nicotinic receptors, which are known to play a part in some illnesses where these symptoms appear, including delirium, schizophrenia spectrum disorders, bipolar disorder, Parkinson, Huntington, and Alzheimer diseases. Beginning with what we know about the emergence of delusions in these illnesses, we advance a hypothesis of cholinergic disturbance in the dorsal striatum where nicotinic receptors are operative. Striosomes are proposed to play a central role in the formation of delusions. This hypothesis is consistent with our current knowledge about the mechanism of action of cholinergic drugs and with our abstract models of basic cognitive mechanisms at the molecular and circuit levels. We conclude by pointing out the need for further research both at the clinical and translational levels.
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Affiliation(s)
- Michael Caton
- The Permanente Medical Group, Kaiser Santa Rosa Department of Psychiatry, 2235 Mercury Way, Santa Rosa, CA, 95047, USA
- Heritage Oaks Hospital, 4250 Auburn Boulevard, Sacramento, CA, 95841, USA
| | - Enrique L M Ochoa
- Heritage Oaks Hospital, 4250 Auburn Boulevard, Sacramento, CA, 95841, USA
- Volunteer Clinical Faculty, Department of Psychiatry and Behavioral Sciences, University of California at Davis, 2230 Stockton Boulevard, Sacramento, CA, 95817, USA
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Institute for Biomedical Research (BIOMED), Faculty of Medical Sciences, UCA-CONICET, Av. Alicia Moreau de Justo 1600, C1107AFF, Buenos Aires, Argentina.
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6
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McClain L, Segreti AM, Nau S, Shaw P, Finegold DN, Pan LA, Peters DG. Chromosome 15q13.3 microduplications are associated with treatment refractory major depressive disorder. GENES BRAIN AND BEHAVIOR 2019; 19:e12628. [PMID: 31828948 DOI: 10.1111/gbb.12628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 11/18/2019] [Accepted: 12/02/2019] [Indexed: 12/25/2022]
Abstract
Major depressive disorder (MDD) affects approximately 15 million Americans. Approximately 2 million of these are classified as being refractory to treatment (TR-MDD). Because of the lack of available therapies for TR-MDD, and the high risk of suicide, there is interest in identifying new treatment modalities and diagnostic methods. Understanding of the impact of genomic copy number variation in the etiology of a variety of neuropsychiatric phenotypes is increasing. Low copy repeat elements at 15q13.3 facilitate non-allelic homologous recombination, resulting in recurrent copy number variants (CNVs). Numerous reports have described association between microdeletions in this region and a variety of neuropsychiatric phenotypes, with CHRNA7 implicated as a candidate gene. However, the pathogenicity of 15q13.3 duplications is less clear. As part of an ongoing study, in which we have identified a number of metabolomic anomalies in spinal fluid from TR-MDD patients, we also evaluated genomic copy number variation in patients (n = 125) and controls (n = 26) via array-based copy number genomic hybridization (CGH); the case frequency was compared with frequencies reported in a prior study as well as a larger population-sized cohort. We identified five TR-MDD patients with microduplications involving CHRNA7. CHRNA7 duplications are the most common CNVs identified by clinical CGH in this cohort. Therefore, this study provides insight into the potential involvement of CHRNA7 duplications in the etiology of TR-MDD and informs those involved with care of affected individuals.
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Affiliation(s)
- Lora McClain
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Anna M Segreti
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Sharon Nau
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Patricia Shaw
- Magee-Womens Research Institute and Foundation, Pittsburgh, Pennsylvania
| | - David N Finegold
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Lisa A Pan
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - David G Peters
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,Magee-Womens Research Institute and Foundation, Pittsburgh, Pennsylvania.,Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Obstetrics, Gynecology and Reproductive Sciences, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
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7
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Quigley H, MacCabe JH. The relationship between nicotine and psychosis. Ther Adv Psychopharmacol 2019; 9:2045125319859969. [PMID: 31308936 PMCID: PMC6604123 DOI: 10.1177/2045125319859969] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 05/15/2019] [Indexed: 01/20/2023] Open
Abstract
Cigarette smoking is strongly associated with psychotic disorders such as schizophrenia. For several decades it was assumed that the relationship could be explained by reverse causation; that smoking was secondary to the illness itself, either through self-medication or a process of institutionalization, or was entirely explained by confounding by cannabis use or social factors. However, studies have exposed that such hypotheses cannot fully explain the association, and more recently a bidirectional relationship has been proposed wherein cigarette smoking may be causally related to risk of psychosis, possibly via a shared genetic liability to smoking and psychosis. We review the evidence for these candidate explanations, using findings from the latest epidemiological, neuroimaging, genetic and preclinical work.
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Affiliation(s)
- Harriet Quigley
- Department of Psychosis Studies, Institute of
Psychiatry, Psychology and Neuroscience, Kings College London, SE5 8AF,
Denmark Hill, London, UK
| | - James H. MacCabe
- Department of Psychosis Studies, Institute of
Psychiatry, Psychology and Neuroscience, Kings College London, London,
UK
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8
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Choueiry J, Blais CM, Shah D, Smith D, Fisher D, Labelle A, Knott V. Combining CDP-choline and galantamine, an optimized α7 nicotinic strategy, to ameliorate sensory gating to speech stimuli in schizophrenia. Int J Psychophysiol 2019; 145:70-82. [PMID: 30790597 DOI: 10.1016/j.ijpsycho.2019.02.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/04/2019] [Accepted: 02/12/2019] [Indexed: 11/18/2022]
Abstract
Neural α7 nicotinic acetylcholine receptor (nAChR) expression and functioning deficits have been extensively associated with cognitive and early sensory gating (SG) impairments in schizophrenia (SCZ) patients and their relatives. SG, the suppression of irrelevant and redundant stimuli, is measured in a conditioning-testing (S1-S2) paradigm eliciting electroencephalography-derived P50 event-related potentials (ERPs), the S2 amplitudes of which are typically suppressed relative to S1. Despite extensive reports of nicotine-related improvements and several decades of research, an efficient nicotinic treatment has yet to be approved for SCZ. Following reports of SG improvements in low P50 suppressing SCZ patients and healthy participants with the α7 agonist, CDP-choline, this pilot study examined the combined modulatory effect of CDP-choline (500 mg) and galantamine (16 mg), a nAChR positive allosteric modulator and acetylcholinesterase inhibitor, on SG to speech stimuli in twenty-four SCZ patients in a randomized, double-blind and placebo-controlled design. As expected, in low P50 suppressors CDP-choline/galantamine (vs. Placebo) improved rP50 and dP50 scores by increasing inhibitory mechanisms as reflected by S2P50 amplitude reductions. Results also suggest a moderating role for auditory verbal hallucinations in treatment response. These preliminary findings provide supportive evidence for the involvement of α7 nAChR activity in speech gating in SCZ and support additional trials, examining different dose combinations and repeated doses of this optimized and personalized targeted α7 cholinergic treatment for SG dysfunction in subgroups of SCZ patients.
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Affiliation(s)
- Joelle Choueiry
- Department of Neuroscience, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Crystal M Blais
- Institute of Cognitive Science, Carleton University, Ottawa, ON, Canada
| | - Dhrasti Shah
- School of Psychology, Faculty of Social Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Dylan Smith
- School of Psychology, Faculty of Social Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Derek Fisher
- Department of Psychology, Faculty of Social Sciences, Mount Saint Vincent University, Halifax, NS, Canada
| | - Alain Labelle
- The Royal Ottawa Mental Health Centre, Ottawa, ON, Canada
| | - Verner Knott
- Department of Neuroscience, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada; Institute of Cognitive Science, Carleton University, Ottawa, ON, Canada; School of Psychology, Faculty of Social Sciences, University of Ottawa, Ottawa, ON, Canada; Department of Psychology, Faculty of Social Sciences, Mount Saint Vincent University, Halifax, NS, Canada; The Royal Ottawa Mental Health Centre, Ottawa, ON, Canada; University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.
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9
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Microglia in the developing prefrontal cortex of rats show dynamic changes following neonatal disconnection of the ventral hippocampus. Neuropharmacology 2018; 146:264-275. [PMID: 30537477 DOI: 10.1016/j.neuropharm.2018.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 10/30/2018] [Accepted: 12/07/2018] [Indexed: 01/19/2023]
Abstract
Impaired ventral hippocampal (VH)-prefrontal cortex (PFC) connectivity is implicated in many cognitive and behavioral disorders. Excitotoxic neonatal VH (nVH) lesion in rat pups has been shown to induce synaptic pruning in the PFC as well as behavioral changes of relevance to developmental neuropsychiatric disorders. In the current study, we hypothesized that microglia, immune cells required for proper brain development and plasticity, may play a role in the development of abnormal behaviors in the nVH-lesioned animals. Ibotenic acid-induced nVH lesion was induced in postnatal day (P)7 male rats. Developmental changes in microglial density, morphology, ultrastructure and gene expression were analyzed in the PFC at P20 and P60. Our results revealed increased microglial reactivity and phagocytic activity in the lesioned rats at P20. Increased mRNA levels of C3 and C1q, complement molecules involved in synaptic pruning, were concomitantly observed. Diminished, but maintained, microglial reactivity and reduced antioxidative defenses were identified in lesioned rats at P60. Behavioral deficits were significantly reduced in the post-pubertal rats by suppressing microglial reactivity by a one-week minocycline treatment immediately after the lesion, These results suggest that early-life disconnection of the VH has long-lasting consequences for microglial functions in the connected structures. Alterations in microglia may underlie synaptic reorganization and behavioral deficits observed following neonatal VH disconnection.
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10
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Aidelbaum R, Labelle A, Baddeley A, Knott V. Assessing the acute effects of CDP-choline on sensory gating in schizophrenia: A pilot study. J Psychopharmacol 2018; 32:541-551. [PMID: 29338621 DOI: 10.1177/0269881117746903] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Deficient sensory gating (SG) in schizophrenia is associated with functional outcome and offers a therapeutic target as it is linked to the altered function/expression of the α7 nicotinic acetylcholine receptors (nAChRs). This study analyzed the effects of citicoline (CDP-choline), a supplement with α7 nAChRs agonist properties, on SG in a sample of schizophrenia (SZ) patients. Using a randomized, placebo-controlled, double-blind design the dose-dependent (500 mg, 1000 mg, 2000 mg) and baseline-dependent (deficient versus normal suppressors) effects of CDP-choline on SG were examined using the P50 event-related potential (ERP) index of SG. Overall analysis failed to demonstrate treatment effects but CDP-choline improved SG (500 mg) in the deficient SZ subgroup by increasing suppression of the S2 P50 amplitude. These findings tentatively support α7 nAChR dysfunction in the expression of SG deficits and suggest further trials to assess the effects of sustained α7 nAChR activation on SG with low doses of CDP-choline.
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Affiliation(s)
- Robert Aidelbaum
- 1 Clinical Neuroelectrophysiology and Cognitive Research Laboratory, University of Ottawa Institute of Mental Health Research, ON, Canada.,2 Department of Psychology, Carleton University, ON, Canada
| | - Alain Labelle
- 3 Schizophrenia Program, Royal Ottawa Mental Health Centre, ON, Canada
| | - Ashley Baddeley
- 1 Clinical Neuroelectrophysiology and Cognitive Research Laboratory, University of Ottawa Institute of Mental Health Research, ON, Canada
| | - Verner Knott
- 1 Clinical Neuroelectrophysiology and Cognitive Research Laboratory, University of Ottawa Institute of Mental Health Research, ON, Canada
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11
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New Targets for Schizophrenia Treatment beyond the Dopamine Hypothesis. Int J Mol Sci 2017; 18:ijms18081689. [PMID: 28771182 PMCID: PMC5578079 DOI: 10.3390/ijms18081689] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 07/30/2017] [Accepted: 08/01/2017] [Indexed: 12/14/2022] Open
Abstract
Schizophrenia has been primarily associated with dopamine dysfunction, and treatments have been developed that target the dopamine pathway in the central nervous system. However, accumulating evidence has shown that the core pathophysiology of schizophrenia might involve dysfunction in dopaminergic, glutamatergic, serotonergic, and gamma-aminobutyric acid (GABA) signaling, which may lead to aberrant functioning of interneurons that manifest as cognitive, behavioral, and social dysfunction through altered functioning of a broad range of macro- and microcircuits. The interactions between neurotransmitters can be modeled as nodes and edges by using graph theory, and oxidative balance, immune, and glutamatergic systems may represent multiple nodes interlocking at a central hub; imbalance within any of these nodes might affect the entire system. Therefore, this review attempts to address novel treatment targets beyond the dopamine hypothesis, including glutamate, serotonin, acetylcholine, GABA, and inflammatory cytokines. Furthermore, we outline that these treatment targets can be possibly integrated with novel treatment strategies aimed at different symptoms or phases of the illness. We anticipate that reversing anomalous activity in these novel treatment targets or combinations between these strategies might be beneficial in the treatment of schizophrenia.
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12
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Keshavan MS, Lawler AN, Nasrallah HA, Tandon R. New drug developments in psychosis: Challenges, opportunities and strategies. Prog Neurobiol 2017; 152:3-20. [PMID: 27519538 PMCID: PMC5362348 DOI: 10.1016/j.pneurobio.2016.07.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 07/11/2016] [Indexed: 02/06/2023]
Abstract
All currently approved drugs for schizophrenia work mainly by dopaminergic antagonism. While they are efficacious for psychotic symptoms, their efficacy is limited for negative symptoms and cognitive deficits which underlie the substantive disability in this illness. Recent insights into the biological basis of schizophrenia, especially in relation to non-dopaminergic mechanisms, have raised the efforts to find novel and effective drug targets, though with relatively little success thus far. Potential impediments to novel drug discovery include the continued use of symptom based disease definitions which leads to etiological and pathophysiological heterogeneity, lack of valid preclinical models for drug testing, and design limitations in clinical trials. These roadblocks can be addressed by (i) characterizing trans-diagnostic, translational pathophysiological dimensions as potential treatment targets, (ii) efficiency, accountability and, transparency in approaches to the clinical trials process, and (iii) leveraging recent advances in genetics and in vitro phenotypes. Accomplishing these goals is urgent given the significant unmet needs in the pharmacological treatment of schizophrenia. As this happens, it is imperative that clinicians employ optimal dosing, measurement-based care, and other best practices in utilizing existing treatments to optimize outcomes for their patients today.
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Affiliation(s)
- Matcheri S Keshavan
- Department of Psychiatry, Beth Israel Deaconess Medical Center and Massachusetts Mental Health Center, Harvard Medical School, United States.
| | - Ashley N Lawler
- Department of Psychiatry, Beth Israel Deaconess Medical Center and Massachusetts Mental Health Center, Harvard Medical School, United States
| | - Henry A Nasrallah
- Department of Neurology & Psychiatry, St Louis University, United States
| | - Rajiv Tandon
- Department of Psychiatry, University of Florida, Gainsville, Florida. and the North FL/South Georgia Veterans' Administration Medical Center, Gainesville, FL 32610, United States; The North Florida/South Georgia Veterans' Administration Medical Center, Gainesville, FL, 32610, United States
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13
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Close JL, Yao Z, Levi BP, Miller JA, Bakken TE, Menon V, Ting JT, Wall A, Krostag AR, Thomsen ER, Nelson AM, Mich JK, Hodge RD, Shehata SI, Glass IA, Bort S, Shapovalova NV, Ngo NK, Grimley JS, Phillips JW, Thompson CL, Ramanathan S, Lein E. Single-Cell Profiling of an In Vitro Model of Human Interneuron Development Reveals Temporal Dynamics of Cell Type Production and Maturation. Neuron 2017; 93:1035-1048.e5. [PMID: 28279351 PMCID: PMC5480972 DOI: 10.1016/j.neuron.2017.02.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/12/2016] [Accepted: 01/30/2017] [Indexed: 12/31/2022]
Abstract
GABAergic interneurons are essential for neural circuit function, and their loss or dysfunction is implicated in human neuropsychiatric disease. In vitro methods for interneuron generation hold promise for studying human cellular and functional properties and, ultimately, for therapeutic cell replacement. Here we describe a protocol for generating cortical interneurons from hESCs and analyze the properties and maturation time course of cell types using single-cell RNA-seq. We find that the cell types produced mimic in vivo temporal patterns of neuron and glial production, with immature progenitors and neurons observed early and mature cortical neurons and glial cell types produced late. By comparing the transcriptomes of immature interneurons to those of more mature neurons, we identified genes important for human interneuron differentiation. Many of these genes were previously implicated in neurodevelopmental and neuropsychiatric disorders.
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Affiliation(s)
- Jennie L Close
- Allen Institute for Brain Science, Seattle, WA 98109, USA.
| | - Zizhen Yao
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Boaz P Levi
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | | | - Vilas Menon
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - Abigail Wall
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | | | - Angel M Nelson
- Allen Institute for Cell Science, Seattle, WA 98109, USA
| | - John K Mich
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | | | - Ian A Glass
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Susan Bort
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - N Kiet Ngo
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | | | | | - Sharad Ramanathan
- Molecular and Cellular Biology Department, Harvard University, Cambridge, MA 02138, USA
| | - Ed Lein
- Allen Institute for Brain Science, Seattle, WA 98109, USA
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14
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Faillace MP, Pisera-Fuster A, Medrano MP, Bejarano AC, Bernabeu RO. Short- and long-term effects of nicotine and the histone deacetylase inhibitor phenylbutyrate on novel object recognition in zebrafish. Psychopharmacology (Berl) 2017; 234:943-955. [PMID: 28130648 DOI: 10.1007/s00213-017-4532-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 01/09/2017] [Indexed: 12/16/2022]
Abstract
RATIONALE Zebrafish have a sophisticated color- and shape-sensitive visual system, so we examined color cue-based novel object recognition in zebrafish. We evaluated preference in the absence or presence of drugs that affect attention and memory retention in rodents: nicotine and the histone deacetylase inhibitor (HDACi) phenylbutyrate (PhB). OBJECTIVES The objective of this study was to evaluate whether nicotine and PhB affect innate preferences of zebrafish for familiar and novel objects after short- and long-retention intervals. METHODS We developed modified object recognition (OR) tasks using neutral novel and familiar objects in different colors. We also tested objects which differed with respect to the exploratory behavior they elicited from naïve zebrafish. RESULTS Zebrafish showed an innate preference for exploring red or green objects rather than yellow or blue objects. Zebrafish were better at discriminating color changes than changes in object shape or size. Nicotine significantly enhanced or changed short-term innate novel object preference whereas PhB had similar effects when preference was assessed 24 h after training. Analysis of other zebrafish behaviors corroborated these results. CONCLUSIONS Zebrafish were innately reluctant or prone to explore colored novel objects, so drug effects on innate preference for objects can be evaluated changing the color of objects with a simple geometry. Zebrafish exhibited recognition memory for novel objects with similar innate significance. Interestingly, nicotine and PhB significantly modified innate object preference.
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Affiliation(s)
- M P Faillace
- Department of Physiology and Institute of Physiology and Biophysics (IFIBIO), School of Medicine, University of Buenos Aires, Paraguay 2155 7th floor, C1121ABG, Ciudad Autónoma de Buenos Aires, Argentina
| | - A Pisera-Fuster
- Department of Physiology and Institute of Physiology and Biophysics (IFIBIO), School of Medicine, University of Buenos Aires, Paraguay 2155 7th floor, C1121ABG, Ciudad Autónoma de Buenos Aires, Argentina
| | - M P Medrano
- Department of Physiology and Institute of Physiology and Biophysics (IFIBIO), School of Medicine, University of Buenos Aires, Paraguay 2155 7th floor, C1121ABG, Ciudad Autónoma de Buenos Aires, Argentina
| | - A C Bejarano
- Department of Physiology and Institute of Physiology and Biophysics (IFIBIO), School of Medicine, University of Buenos Aires, Paraguay 2155 7th floor, C1121ABG, Ciudad Autónoma de Buenos Aires, Argentina
| | - R O Bernabeu
- Department of Physiology and Institute of Physiology and Biophysics (IFIBIO), School of Medicine, University of Buenos Aires, Paraguay 2155 7th floor, C1121ABG, Ciudad Autónoma de Buenos Aires, Argentina.
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15
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Cholinergic Protection in Ischemic Brain Injury. SPRINGER SERIES IN TRANSLATIONAL STROKE RESEARCH 2017. [DOI: 10.1007/978-3-319-45345-3_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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16
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Parikh V, Kutlu MG, Gould TJ. nAChR dysfunction as a common substrate for schizophrenia and comorbid nicotine addiction: Current trends and perspectives. Schizophr Res 2016; 171:1-15. [PMID: 26803692 PMCID: PMC4762752 DOI: 10.1016/j.schres.2016.01.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/07/2016] [Accepted: 01/10/2016] [Indexed: 11/18/2022]
Abstract
INTRODUCTION The prevalence of tobacco use in the population with schizophrenia is enormously high. Moreover, nicotine dependence is found to be associated with symptom severity and poor outcome in patients with schizophrenia. The neurobiological mechanisms that explain schizophrenia-nicotine dependence comorbidity are not known. This study systematically reviews the evidence highlighting the contribution of nicotinic acetylcholine receptors (nAChRs) to nicotine abuse in schizophrenia. METHODS Electronic data bases (Medline, Google Scholar, and Web of Science) were searched using the selected key words that match the aims set forth for this review. A total of 276 articles were used for the qualitative synthesis of this review. RESULTS Substantial evidence from preclinical and clinical studies indicated that dysregulation of α7 and β2-subunit containing nAChRs account for the cognitive and affective symptoms of schizophrenia and nicotine use may represent a strategy to remediate these symptoms. Additionally, recent meta-analyses proposed that early tobacco use may itself increase the risk of developing schizophrenia. Genetic studies demonstrating that nAChR dysfunction that may act as a shared vulnerability factor for comorbid tobacco dependence and schizophrenia were found to support this view. The development of nAChR modulators was considered an effective therapeutic strategy to ameliorate psychiatric symptoms and to promote smoking cessation in schizophrenia patients. CONCLUSIONS The relationship between schizophrenia and smoking is complex. While the debate for the self-medication versus addiction vulnerability hypothesis continues, it is widely accepted that a dysfunction in the central nAChRs represent a common substrate for various symptoms of schizophrenia and comorbid nicotine dependence.
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Affiliation(s)
- Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19112, United States.
| | - Munir Gunes Kutlu
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19112, United States
| | - Thomas J Gould
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA 19112, United States
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17
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Walling D, Marder SR, Kane J, Fleischhacker WW, Keefe RSE, Hosford DA, Dvergsten C, Segreti AC, Beaver JS, Toler SM, Jett JE, Dunbar GC. Phase 2 Trial of an Alpha-7 Nicotinic Receptor Agonist (TC-5619) in Negative and Cognitive Symptoms of Schizophrenia. Schizophr Bull 2016; 42:335-43. [PMID: 26071208 PMCID: PMC4753586 DOI: 10.1093/schbul/sbv072] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVES This trial was conducted to test the effects of an alpha7 nicotinic receptor full agonist, TC-5619, on negative and cognitive symptoms in subjects with schizophrenia. METHODS In 64 sites in the United States, Russia, Ukraine, Hungary, Romania, and Serbia, 477 outpatients (18-65 years; male 62%; 55% tobacco users) with schizophrenia, treated with a new-generation antipsychotic, were randomized to 24 weeks of placebo (n = 235), TC-5619, 5mg (n = 121), or TC-5619, 50 mg (n = 121), administered orally once daily. The primary efficacy measure was the Scale for the Assessment of Negative Symptoms (SANS) composite score. Key secondary measures were the Cogstate Schizophrenia Battery (CSB) composite score and the University of California San Diego Performance-Based Skills Assessment-Brief Version (UPSA-B) total score. Secondary measures included: Positive and Negative Syndrome Scale in Schizophrenia (PANSS) total and subscale scores, SANS domain scores, CSB item scores, Clinical Global Impression-Global Improvement (CGI-I) score, CGI-Severity (CGI-S) score, and Subject Global Impression-Cognition (SGI-Cog) total score. RESULTS SANS score showed no statistical benefit for TC-5619 vs placebo at week 24 (5 mg, 2-tailed P = .159; 50 mg, P = .689). Likewise, no scores of CSB, UPSA-B, PANSS, CGI-I, CGI-S, or SGI-Cog favored TC-5619 (P > .05). Sporadic statistical benefit favoring TC-5619 in some of these outcome measures were observed in tobacco users, but these benefits did not show concordance by dose, country, gender, or other relevant measures. TC-5619 was generally well tolerated. CONCLUSION These results do not support a benefit of TC-5619 for negative or cognitive symptoms in schizophrenia.
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Affiliation(s)
| | - Stephen R. Marder
- Desert Pacific Mental Illness Research, Education, and Clinical Center UCLA Semel Institute for Neuroscience, Los Angeles, CA
| | - John Kane
- Department of Psychiatry, The Zucker Hillside Hospital, Glen Oaks, NY
| | - W. Wolfgang Fleischhacker
- Department for Psychiatry and Psychotherapy, Division of Biological Psychiatry, Medical University Innsbruck, Innsbruck, Austria
| | - Richard S. E. Keefe
- Schizophrenia Research Group, Psychiatry & Behavioral Sciences, Division of Medical Psychology, School of Medicine, Duke University, Durham, NC
| | - David A. Hosford
- Department of Clinical Development and Regulatory Affairs, Targacept Inc., Winston-Salem, NC
| | - Chris Dvergsten
- Department of Clinical Development and Regulatory Affairs, Targacept Inc., Winston-Salem, NC
| | - Anthony C. Segreti
- Department of Clinical Development and Regulatory Affairs, Targacept Inc., Winston-Salem, NC
| | - Jessica S. Beaver
- Department of Clinical Development and Regulatory Affairs, Targacept Inc., Winston-Salem, NC
| | - Steven M. Toler
- Department of Clinical Development and Regulatory Affairs, Targacept Inc., Winston-Salem, NC
| | - John E. Jett
- Department of Clinical Development and Regulatory Affairs, Targacept Inc., Winston-Salem, NC
| | - Geoffrey C. Dunbar
- Department of Clinical Development and Regulatory Affairs, Targacept Inc., Winston-Salem, NC
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18
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Ouach A, Pin F, Bertrand E, Vercouillie J, Gulhan Z, Mothes C, Deloye JB, Guilloteau D, Suzenet F, Chalon S, Routier S. Design of α7 nicotinic acetylcholine receptor ligands using the (het)Aryl-1,2,3-triazole core: Synthesis, in vitro evaluation and SAR studies. Eur J Med Chem 2016; 107:153-64. [DOI: 10.1016/j.ejmech.2015.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/30/2015] [Accepted: 11/01/2015] [Indexed: 10/22/2022]
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19
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Tregellas JR, Smucny J, Legget KT, Stevens KE. Effects of a ketogenic diet on auditory gating in DBA/2 mice: A proof-of-concept study. Schizophr Res 2015; 169:351-354. [PMID: 26453015 PMCID: PMC4827327 DOI: 10.1016/j.schres.2015.09.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/18/2015] [Accepted: 09/21/2015] [Indexed: 11/20/2022]
Abstract
Although the ketogenic diet has shown promise in a pilot study and case report in schizophrenia, its effects in animal models of hypothesized disease mechanisms are unknown. This study examined effects of treatment with the ketogenic diet on hippocampal P20/N40 gating in DBA/2 mice, a translational endophenotype that mirrors inhibitory deficits in P50 sensory gating in schizophrenia patients. As expected, the diet increased blood ketone levels. Animals with the highest ketone levels showed the lowest P20/N40 gating ratios. These preliminary results suggest that the ketogenic diet may effectively target sensory gating deficits and is a promising area for additional research in schizophrenia.
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Affiliation(s)
- Jason R Tregellas
- Research Service, Denver VA Medical Center, Denver, CO, USA; Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Jason Smucny
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kristina T Legget
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Karen E Stevens
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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20
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Spagna A, Dong Y, Mackie MA, Li M, Harvey PD, Tian Y, Wang K, Fan J. Clozapine improves the orienting of attention in schizophrenia. Schizophr Res 2015; 168:285-91. [PMID: 26298539 DOI: 10.1016/j.schres.2015.08.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/04/2015] [Accepted: 08/06/2015] [Indexed: 10/23/2022]
Abstract
Attentional deficits are prominent in the cognitive profile of patients with schizophrenia. However, it remains unclear whether treatment with clozapine, an atypical antipsychotic and first-line intervention used to reduce positive and negative symptoms of psychosis, improves the attentional functions. We used the revised attention network test to measure alerting, orienting, and executive control of attention both pre- and post-treatment with clozapine in patients with schizophrenia (n=32) and compared performance to healthy controls (n=32). Results revealed that there were deficits in all three attentional functions pre-treatment, and while clozapine improved the orienting function in patients with schizophrenia, there was no evidence for improvement in the alerting and executive control of attention. The enhancement of the orienting function by clozapine may increase the ability of patients with schizophrenia to orient towards objects and thoughts of interest.
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Affiliation(s)
- Alfredo Spagna
- Department of Psychology, Queens College, The City University of New York, Queens, NY, USA
| | - Yi Dong
- Hefei Psychiatry Hospital, Hefei, Anhui Province, China
| | - Melissa-Ann Mackie
- Department of Psychology, Queens College, The City University of New York, Queens, NY, USA
| | - Ming Li
- Department of Psychology, University of Nebraska-Lincoln, NE, USA
| | - Philip D Harvey
- Department of Psychiatry, University of Miami Miller School of Medicine, Miami, FL, USA; Research Service, Bruce W. Carter VA Medical Center, Miami, FL, USA
| | - Yanghua Tian
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
| | - Kai Wang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China.
| | - Jin Fan
- Department of Psychology, Queens College, The City University of New York, Queens, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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21
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Kolisnyk B, Al-Onaizi MA, Prado VF, Prado MAM. α7 nicotinic ACh receptor-deficient mice exhibit sustained attention impairments that are reversed by β2 nicotinic ACh receptor activation. Br J Pharmacol 2015. [PMID: 26222090 DOI: 10.1111/bph.13260] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Disruptions of executive function, including attentional deficits, are a hallmark of a number of diseases. ACh in the prefrontal cortex regulates attentive behaviour; however, the role of α7 nicotinic ACh receptor (α7nAChR) in attention is contentious. EXPERIMENTAL APPROACH In order to probe attention, we trained both wild-type and α7nAChR knockout mice on a touch screen-based five-choice serial reaction time task (5-CSRT). Following training procedures, we then tested sustained attention using a probe trial experiment. To further differentiate the role of specific nicotinic receptors in attention, we then tested the effects of both α7nAChR and β2nAChR agonists on the performance of both wild-type and knockout mice on the 5-CSRT task. KEY RESULTS At low doses, α7nAChR agonists improved attentional performance of wild-type mice, while high doses had deleterious effects on attention. α7nAChR knockout mice displayed deficits in sustained attention that were not ameliorated by α7nAChR agonists. However, these deficits were completely reversed by the administration of a β2nAChR agonist. Furthermore, administration of a β2nAChR agonist in α7nAChR knockout mice elicited similar biochemical response in the prefrontal cortex as the administration of α7nAChR agonists in wild-type mice. CONCLUSIONS AND IMPLICATIONS Our experiments reveal an intricate relationship between distinct nicotinic receptors to regulate attentional performance and provide the basis for targeting β2nAChRs pharmacologically to decrease attentional deficits due to a dysfunction in α7nAChRs.
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Affiliation(s)
- Benjamin Kolisnyk
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Mohammed A Al-Onaizi
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada
| | - Vania F Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada
| | - Marco A M Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada
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22
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Smucny J, Stevens KE, Tregellas JR. The antiepileptic drug levetiracetam improves auditory gating in DBA/2 mice. NPJ SCHIZOPHRENIA 2015; 1:15002. [PMID: 26317115 PMCID: PMC4548960 DOI: 10.1038/npjschz.2015.2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/26/2014] [Accepted: 01/05/2015] [Indexed: 11/21/2022]
Abstract
Schizophrenia is associated with deficits in P50 gating. This deficit is preclinically modeled in the DBA/2 mouse by depth recordings in the hippocampus. Neurobiologically, the deficit may be due to dysfunction in inhibitory circuitry. It follows that anti-epileptic drugs which impact this circuitry, such as levetiracetam (LEV), may improve gating. To that end, the goal of this study was to evaluate the ability of LEV to normalize sensory gating in the DBA/2 mouse. Gating of the murine analog of the P50, the P20-N40, was evaluated from in vivo hippocampal recordings in 39 male DBA/2 mice. Gating effects were evaluated using four doses of LEV (3, 10, 30, and 100 mg/kg). The 10 mg/kg dose improved P20-N40 gating (P = 0.016). No other doses significantly affected gating. Low-dose LEV may improve P20-N40 gating in the DBA/2 mouse model of schizophrenia. Low-doses of LEV may improve P20-N40 gating in the DBA/2 mouse model of schizophrenia and warrant further investigation in the illness.
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Affiliation(s)
- Jason Smucny
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Research Service, Denver VA Medical Center, Denver, CO, USA
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Karen E Stevens
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Jason R Tregellas
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Research Service, Denver VA Medical Center, Denver, CO, USA
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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23
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Smucny J, Stevens KE, Olincy A, Tregellas JR. Translational utility of rodent hippocampal auditory gating in schizophrenia research: a review and evaluation. Transl Psychiatry 2015; 5:e587. [PMID: 26101850 PMCID: PMC4490287 DOI: 10.1038/tp.2015.77] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/14/2015] [Accepted: 05/04/2015] [Indexed: 01/15/2023] Open
Abstract
Impaired gating of the auditory evoked P50 potential is one of the most pharmacologically well-characterized features of schizophrenia. This deficit is most commonly modeled in rodents by implanted electrode recordings from the hippocampus of the rodent analog of the P50, the P20-N40. The validity and effectiveness of this tool, however, has not been systematically reviewed. Here, we summarize findings from studies that have examined the effects of pharmacologic modulation on gating of the rodent hippocampal P20-N40 and the human P50. We show that drug effects on the P20-N40 are highly predictive of human effects across similar dose ranges. Furthermore, mental status (for example, anesthetized vs alert) does not appear to diminish the predictive capacity of these recordings. We then discuss hypothesized neuropharmacologic mechanisms that may underlie gating effects for each drug studied. Overall, this review supports continued use of hippocampal P20-N40 gating as a translational tool for schizophrenia research.
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Affiliation(s)
- J Smucny
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Research Service, Denver VA Medical Center, Denver, CO, USA
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - K E Stevens
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - A Olincy
- Research Service, Denver VA Medical Center, Denver, CO, USA
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - J R Tregellas
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Research Service, Denver VA Medical Center, Denver, CO, USA
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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24
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De la Torre GG, Perez MJ, Ramallo MA, Randolph C, González-Villegas MB. Screening of Cognitive Impairment in Schizophrenia: Reliability, Sensitivity, and Specificity of the Repeatable Battery for the Assessment of Neuropsychological Status in a Spanish Sample. Assessment 2015; 23:221-31. [PMID: 25934161 DOI: 10.1177/1073191115583715] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND In recent years, a number of studies focusing on the evaluation of neuropsychological deficits in individuals with schizophrenia have shown deficits that include several cognitive functions. Attention deficits as well as memory or executive function deficits are common in this kind of disorder together with sustained attention problems, working memory deficiencies, and problem-solving difficulties, among many others. Currently, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is gaining special importance in the evaluation of the cognitive deficits associated with schizophrenia. METHOD In this article, we describe an RBANS screening in a sample of 88 Spanish patients diagnosed with schizophrenia. We also aimed to check the battery's reliability, sensitivity, and specificity in the studied sample. We performed a comparative study with 88 healthy participants. RESULTS The results showed a reliability index value of α = .795 and an item value of α = .762. For total test reliability, we obtained an index value of α = .761 and an item value of α = .762. Sensitivity score was 87.5% and specificity 86.4%. CONCLUSIONS RBANS obtained good reliability, sensitivity, and specificity scores and represents a good screening tool in detecting cognitive deficits associated with schizophrenia.
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25
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Stevens KE, Zheng L, Floyd KL, Stitzel JA. Maximizing the effect of an α7 nicotinic receptor PAM in a mouse model of schizophrenia-like sensory inhibition deficits. Brain Res 2015; 1611:8-17. [PMID: 25744161 DOI: 10.1016/j.brainres.2015.02.044] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 02/20/2015] [Accepted: 02/21/2015] [Indexed: 12/30/2022]
Abstract
Positive allosteric modulators (PAMs) for the α7 nicotinic receptor hold promise for the treatment of sensory inhibition deficits observed in schizophrenia patients. Studies of these compounds in the DBA/2 mouse, which models the schizophrenia-related deficit in sensory inhibition, have shown PAMs to be effective in improving the deficit. However, the first published clinical trial of a PAM for both sensory inhibition deficits and related cognitive difficulties failed, casting a shadow on this therapeutic approach. The present study used both DBA/2 mice, and C3H Chrna7 heterozygote mice to assess the ability of the α7 PAM, PNU-120596, to improve sensory inhibition. Both of these strains of mice have reduced hippocampal α7 nicotinic receptor numbers and deficient sensory inhibition similar to schizophrenia patients. Low doses of PNU-120596 (1 or 3.33mg/kg) were effective in the DBA/2 mouse but not the C3H Chrna7 heterozygote mouse. Moderate doses of the selective α7 nicotinic receptor agonist, choline chloride (10 or 33mg/kg), were also ineffective in improving sensory inhibition in the C3H Chrna7 heterozygote mouse. However, combining the lowest doses of both PNU-120596 and choline chloride in this mouse model did improve sensory inhibition. We propose here that the difference in efficacy of PNU-120596 between the 2 mouse strains is driven by differences in hippocampal α7 nicotinic receptor numbers, such that C3H Chrna7 heterozygote mice require additional direct stimulation of the α7 receptors. These data may have implications for further clinical testing of putative α7 nicotinic receptor PAMs.
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Affiliation(s)
- Karen E Stevens
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA.
| | - Lijun Zheng
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Kirsten L Floyd
- Department of Psychiatry, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Jerry A Stitzel
- Institute for Behavioral Genetics, University of Colorado, Boulder, Boulder, CO, USA
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Neurocognitive effects of acute choline supplementation in low, medium and high performer healthy volunteers. Pharmacol Biochem Behav 2015; 131:119-29. [PMID: 25681529 DOI: 10.1016/j.pbb.2015.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/20/2015] [Accepted: 02/04/2015] [Indexed: 12/28/2022]
Abstract
Novel pharmacological treatments targeting alpha 7 nicotinic acetylcholine receptor (α7 nAChR) hypofunction in schizophrenia have shown mixed success in ameliorating cognitive impairments associated with this disorder. Choline, a selective agonist at α7 receptors is increased with oral administration of cytidine 5'-diphosphocholine (CDP-choline), the cognitive effects of which were assessed in healthy volunteers. Using the CogState test battery, behavioral performance in schizophrenia-relevant cognitive domains was assessed in 24 male participants following a single low (500mg) and moderate (1000mg) dose of CDP-choline. Relative to placebo, CDP-choline improved processing speed, working memory, verbal learning, verbal memory, and executive function in low baseline performers, while exerting no effects in medium baseline performers, and diminishing cognition in high baseline performers. Dose effects varied with cognitive domain but were evident with both the 500mg and 1000mg doses. These preliminary findings of cognitive enhancement in relatively impaired performers are consistent with the α7 receptor mechanism and support further trials with CDP-choline as a potential pro-cognitive strategy for cognitive impairment in schizophrenia.
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27
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Koch M, Schmiedt-Fehr C, Mathes B. Neuropharmacology of altered brain oscillations in schizophrenia. Int J Psychophysiol 2015; 103:62-8. [PMID: 25681533 DOI: 10.1016/j.ijpsycho.2015.02.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Impairments in spatial and temporal integration of brain network activity are a core feature of schizophrenia. Neural network oscillatory activity is considered to be fundamentally important in coordinating neural activity throughout the brain. Hence, exploration of brain oscillations has become an indispensible tool to study the neural basis of mental illnesses. However, most of the studies in schizophrenia include medicated patients. This implicates the question to what extent are changes in the electrophysiological parameters genuine illness effects, genuine drug effects or a mixture of both. We here provide a short overview of the neuropharmacology of brain oscillations with respect to schizophrenia. The core assumption of the so-called "pharmaco-EEG" approach is that drug effects on mental and cognitive functions are reflected in changes in quantitative EEG parameters. Hence, clinical efficacy of drugs might be predicted on the basis of the neuropharmacology of electrophysiological measures, such as brain oscillations. Vice versa, knowledge of drug effects on brain oscillations can be of essence in understanding schizophrenia. However, the current literature lacks systematic findings, because of at least two problems. First, the pharmacology of most antipsychotic drugs is complex including interactions with several transmitter receptors. Second, the neuropathology of schizophrenia still has no pathognomonic signature. Even though it is presently not possible to clearly dissociate drug- and illness effects in neural oscillations, this review emphasizes future studies to foster the understanding of this relationship in schizophrenia and other neuropsychiatric diseases.
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Affiliation(s)
- Michael Koch
- Brain Research Institute, Dept. of Neuropharmacology, University of Bremen, Hochschulring 18, 28359 Bremen, Germany.
| | - Christina Schmiedt-Fehr
- Institute of Psychology and Cognition Research, University of Bremen, Grazerstr. 4, 28359 Bremen, Germany
| | - Birgit Mathes
- Institute of Psychology and Cognition Research, University of Bremen, Grazerstr. 4, 28359 Bremen, Germany
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Rowe AR, Mercer L, Casetti V, Sendt KV, Giaroli G, Shergill SS, Tracy DK. Dementia praecox redux: a systematic review of the nicotinic receptor as a target for cognitive symptoms of schizophrenia. J Psychopharmacol 2015; 29:197-211. [PMID: 25567553 DOI: 10.1177/0269881114564096] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Most individuals with schizophrenia suffer some cognitive dysfunction: such deficits are predictive of longer-term functioning; and current dopamine-blocking antipsychotics have made little impact on this domain. There is a pressing need to develop novel pharmacological agents to tackle this insidious but most disabling of problems. The acetylcholinergic system is involved in cognitive and attentional processing, and its metabotropic and nicotinic receptors are widespread throughout the brain. Deficits in acetylcholinergic functioning occur in schizophrenia, and high rates of tobacco smoking have been posited to represent a form of self-medication. The nicotinic acetylcholine receptor (nAChR) has emerged as a putative target to improve cognitive deficits in schizophrenia, and this study systematically reviewed the emerging data. Nineteen studies were identified, covering three compound classes: agonists at the α7 and α 4β2 nAChRs, and positive allosteric modulators. Overall data are underwhelming: some studies showed significant improvements in cognition but as many studies had negative findings. It remains unclear if this represents drug limitations or nascent study methodology problems. The literature is particularly hindered by variability in inclusion of smokers, generally small sample sizes, and a lack of consensus on cognitive test batteries. Future work should evaluate longer-term outcomes, and, particularly, the effects of concomitant cognitive training.
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Affiliation(s)
- Arann R Rowe
- The Institute of Psychiatry, King's College London, London, UK
| | - Louise Mercer
- The Institute of Psychiatry, King's College London, London, UK
| | - Valentina Casetti
- The Institute of Psychiatry, King's College London, London, UK Oxleas NHS Foundation Trust, London, UK
| | | | | | - Sukhwinder S Shergill
- The Institute of Psychiatry, King's College London, London, UK South London and Maudsley NHS Foundation Trust, London, UK
| | - Derek K Tracy
- The Institute of Psychiatry, King's College London, London, UK Oxleas NHS Foundation Trust, London, UK
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Mattei D, Schweibold R, Wolf SA. Brain in flames - animal models of psychosis: utility and limitations. Neuropsychiatr Dis Treat 2015; 11:1313-29. [PMID: 26064050 PMCID: PMC4455860 DOI: 10.2147/ndt.s65564] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The neurodevelopmental hypothesis of schizophrenia posits that schizophrenia is a psychopathological condition resulting from aberrations in neurodevelopmental processes caused by a combination of environmental and genetic factors which proceed long before the onset of clinical symptoms. Many studies discuss an immunological component in the onset and progression of schizophrenia. We here review studies utilizing animal models of schizophrenia with manipulations of genetic, pharmacologic, and immunological origin. We focus on the immunological component to bridge the studies in terms of evaluation and treatment options of negative, positive, and cognitive symptoms. Throughout the review we link certain aspects of each model to the situation in human schizophrenic patients. In conclusion we suggest a combination of existing models to better represent the human situation. Moreover, we emphasize that animal models represent defined single or multiple symptoms or hallmarks of a given disease.
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Affiliation(s)
- Daniele Mattei
- Department of Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Regina Schweibold
- Department of Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany ; Department of Neurosurgery, Helios Clinics, Berlin, Germany
| | - Susanne A Wolf
- Department of Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
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30
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Hashimoto K. Targeting of α7 Nicotinic Acetylcholine Receptors in the Treatment of Schizophrenia and the Use of Auditory Sensory Gating as a Translational Biomarker. Curr Pharm Des 2015; 21:3797-806. [PMID: 26044974 PMCID: PMC5024727 DOI: 10.2174/1381612821666150605111345] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/04/2015] [Indexed: 11/22/2022]
Abstract
Accumulating evidence suggests that the α7 subtype of nicotinic acetylcholine receptors (nAChRs) plays a key role in inflammatory processes, thought to be involved in the pathophysiology of neuropsychiatric diseases, such as schizophrenia and Alzheimer's disease. Preclinical and clinical studies showed that the diminished suppression of P50 auditory evoked potentials in patients with schizophrenia may be associated with a decreased density of α7 nAChRs in the brain. This points to a role for auditory sensory gating (P50) as a translational biomarker. A number of agonists and positive allosteric modulators (PAMs) for α7 nAChR promoted beneficial effects in animal models with sensory gating and cognitive deficits. Additionally, several clinical studies showed that α7 nAChR agonists could improve suppression in auditory P50 evoked potentials, as well as cognitive deficits, and negative symptoms in patients with schizophrenia. Taken together, α7 nAChR presents as an extremely attractive therapeutic target for schizophrenia. In this article, the author discusses recent findings on α7 nAChR agonists such as DMXB-A, RG3487, TC-5619, tropisetron, EVP-6124 (encenicline), ABT-126, AQW051 and α7 nAChR PAMs such as JNJ-39393406, PNU- 120596 and AVL-3288 (also known as UCI-4083), and their potential as therapeutic drugs for neuropsychiatric diseases, such as schizophrenia.
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Affiliation(s)
- Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic, Mental Health, 1-8-1 Inohana, Chiba 260-8670, Japan.
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31
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Kalappa BI, Sun F, Johnson SR, Jin K, Uteshev VV. A positive allosteric modulator of α7 nAChRs augments neuroprotective effects of endogenous nicotinic agonists in cerebral ischaemia. Br J Pharmacol 2014; 169:1862-78. [PMID: 23713819 DOI: 10.1111/bph.12247] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 05/08/2013] [Accepted: 05/16/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Activation of α7 nicotinic acetylcholine receptors (nAChRs) can be neuroprotective. However, endogenous choline and ACh have not been regarded as potent neuroprotective agents because physiological levels of choline/ACh do not produce neuroprotective levels of α7 activation. This limitation may be overcome by the use of type-II positive allosteric modulators (PAMs-II) of α7 nAChRs, such as 1-(5-chloro-2,4-dimethoxyphenyl)-3-(5-methylisoxazol-3-yl)-urea (PNU-120596). This proof-of-concept study presents a novel neuroprotective paradigm that converts endogenous choline/ACh into potent neuroprotective agents in cerebral ischaemia by inhibiting α7 nAChR desensitization using PNU-120596. EXPERIMENTAL APPROACH An electrophysiological ex vivo cell injury assay (to quantify the susceptibility of hippocampal neurons to acute injury by complete oxygen and glucose deprivation; COGD) and an in vivo middle cerebral artery occlusion model of ischaemia were used in rats. KEY RESULTS Choline (20-200 μM) in the presence, but not absence of 1 μM PNU-120596 significantly delayed anoxic depolarization/injury of hippocampal CA1 pyramidal neurons, but not CA1 stratum radiatum interneurons, subjected to COGD in acute hippocampal slices and these effects were blocked by 20 nM methyllycaconitine, a selective α7 antagonist, thus, activation of α7 nAChRs was required. PNU-120596 alone was ineffective ex vivo. In in vivo experiments, both pre- and post-ischaemia treatments with PNU-120596 (30 mg·kg(-1) , s.c. and 1 mg·kg(-1) , i.v., respectively) significantly reduced the cortical/subcortical infarct volume caused by transient focal cerebral ischaemia. PNU-120596 (1 mg·kg(-1) , i.v., 30 min post-ischaemia) remained neuroprotective in rats subjected to a choline-deficient diet for 14 days prior to experiments. CONCLUSIONS AND IMPLICATIONS PNU-120596 and possibly other PAMs-II significantly improved neuronal survival in cerebral ischaemia by augmenting neuroprotective effects of endogenous choline/ACh.
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Affiliation(s)
- Bopanna I Kalappa
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
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Pidoplichko VI, Prager EM, Aroniadou-Anderjaska V, Braga MFM. α7-Containing nicotinic acetylcholine receptors on interneurons of the basolateral amygdala and their role in the regulation of the network excitability. J Neurophysiol 2013; 110:2358-69. [PMID: 24004528 DOI: 10.1152/jn.01030.2012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The basolateral amygdala (BLA) plays a key role in fear-related learning and memory, in the modulation of cognitive functions, and in the overall regulation of emotional behavior. Pathophysiological alterations involving hyperexcitability in this brain region underlie anxiety and other emotional disorders as well as some forms of epilepsy. GABAergic interneurons exert a tight inhibitory control over the BLA network; understanding the mechanisms that regulate their activity is necessary for understanding physiological and disordered BLA functions. The BLA receives dense cholinergic input from the basal forebrain, affecting both normal functions and dysfunctions of the amygdala, but the mechanisms involved in the cholinergic regulation of inhibitory activity in the BLA are unclear. Using whole cell recordings in rat amygdala slices, here we demonstrate that the α(7)-containing nicotinic acetylcholine receptors (α(7)-nAChRs) are present on somatic or somatodendritic regions of BLA interneurons. These receptors are active in the basal state enhancing GABAergic inhibition, and their further, exogenous activation produces a transient but dramatic increase of spontaneous inhibitory postsynaptic currents in principal BLA neurons. In the absence of AMPA/kainate receptor antagonists, activation of α(7)-nAChRs in the BLA network increases both GABAergic and glutamatergic spontaneous currents in BLA principal cells, but the inhibitory currents are enhanced significantly more than the excitatory currents, reducing overall excitability. The anxiolytic effects of nicotine as well as the role of the α(7)-nAChRs in seizure activity involving the amygdala and in mental illnesses, such as schizophrenia and Alzheimer's disease, may be better understood in light of the present findings.
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Affiliation(s)
- Volodymyr I Pidoplichko
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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33
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Knott V, de la Salle S, Smith D, Phillipe T, Dort H, Choueiry J, Impey D. Baseline dependency of nicotine's sensory gating actions: similarities and differences in low, medium and high P50 suppressors. J Psychopharmacol 2013; 27:790-800. [PMID: 23744798 DOI: 10.1177/0269881113490449] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Reduced suppression of the P50 auditory event-related potential in schizophrenia patients relative to normal controls is indicative of a sensory gating deficit and is one of the most robust findings reported for functional brain abnormalities in this disorder. However, there is considerable gating variability in patients and controls and there is little understanding as to how inter-individual differences moderate gating responses to drugs and nicotinic agonists in particular, which have shown potential to reverse gating deficits. In this study the effects of acutely administered nicotine (gum, 6 mg) on sensory gating in a paired (S₁-S₂) auditory stimulus paradigm were investigated in 57 healthy, non-smoking volunteers stratified as low (n = 19), medium (n = 19) and high (n = 19) P50 suppressors on the basis of three separate baseline derived gating indices, P50 ratios, P50 difference scores, and gating difference waveforms. Relative to placebo, nicotine consistently improved gating in low suppressors as stratified with all three gating indices, exerted no effects in medium suppressors and reduced gating in high suppressors. Analysis of individual stimulus (S₂, S₂) amplitudes showed distinctly different mechanisms of action underlying nicotine effects in individuals with low and high baseline suppression. The results parallel similar findings of baseline-dependency in the gating effects of several antipsychotic drugs in healthy volunteers and support the use of group segmentation as a translational model in novel cognitive drug development for schizophrenia.
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Affiliation(s)
- Verner Knott
- University of Ottawa Institute of Mental Health Research, Ottawa, Canada.
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Stevens KE, Zheng L, Abrams DJ. Intermittent versus continuous central administration of clozapine in DBA/2 mice, improvement in sensory inhibition deficits. Schizophr Res 2013; 149:121-6. [PMID: 23863771 DOI: 10.1016/j.schres.2013.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/23/2013] [Accepted: 06/02/2013] [Indexed: 11/30/2022]
Abstract
Deficient sensory inhibition, the failure to inhibit responses to repeated stimuli, is a hallmark of schizophrenia, and is thought to be related to difficulties with attention and working memory. Sensory inhibition is assessed by comparing the auditory-evoked EEG responses to 2 closely-spaced identical stimuli. Normal individuals show suppressed response to the second stimulus while schizophrenia patients have responses of similar magnitude to both stimuli. This deficit has been linked to polymorphisms in the promoter for the α7 nicotinic receptor gene, resulting in reduced numbers of receptors on hippocampal interneurons. This deficit is modeled in DBA/2 mice which also show a polymorphism in the promoter for the α7 nicotinic receptor gene and reduced numbers of hippocampal α7 receptors. Systemic administration of clozapine, the most efficacious antipsychotic medication, improves sensory inhibition deficits in both schizophrenia patients and DBA/2 mice. We have previously shown that acute intracerebroventricular (ICV) injections of clozapine induced similar improvement in sensory inhibition in DBA/2 mice. Here we demonstrate the efficacy of chronic ICV clozapine administration in improving sensory inhibition in DBA2 mice. Mice received ICV vehicle, 3, 7.5, 15 or 30 μg of clozapine, either continuously or as a once-per-day injection. Mice were recorded on the 7th day of drug delivery. Both approaches produced improved sensory inhibition, but the daily bolus injection was effective at a lower dose (3 μg/day) than the continuous delivery (15 μg/day). The bolus injections also showed significant improvement up to 36 h post injection thus suggesting that this approach may be more efficacious.
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Affiliation(s)
- Karen E Stevens
- Medical Research Service, VA Medical Center, 1055 Clermont Street, Denver, CO 80220, USA.
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35
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Effects of an alpha7 nicotinic receptor agonist and stress on spatial memory in an animal model of Alzheimer's disease. BIOMED RESEARCH INTERNATIONAL 2013; 2013:952719. [PMID: 24058919 PMCID: PMC3766554 DOI: 10.1155/2013/952719] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/24/2013] [Accepted: 07/25/2013] [Indexed: 01/23/2023]
Abstract
The aim of the present study was to test the effects of PNU-282987 on spatial learning and memory and hippocampal neurogenesis in both intact and chronically stressed transgenic mice. Transgenic mice with susceptibility to Alzheimer's disease (AD) under immobilization stress and not-stressed animals receiving 0 and 1 mg/kg of PNU-282987 (PNU) were evaluated in a water maze task. The effects of PNU and stress on proliferation of new cells in the hippocampus of these animals were also assessed. The latency to escape the platform was significantly higher in transgenic stressed mice compared to those in the wild stressed group, as well as in transgenic animals without PNU compared to control wild group. On retention of the task, differences emerged on stressed wild animals, PNU wild group, and stressed wild mice receiving PNU. However, no significant differences were detected on new cell proliferation. The results of the present study did not show any impact of stress in acquisition of a spatial task both in wild and transgenic mice. No clear effects of PNU on acquisition of a spatial task in transgenic mice with susceptibility to AD were detected. Although PNU and stress effects were detected on retention of the task in wild animals, no changes were noted in transgenic mice.
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36
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Gould TJ, Leach PT. Cellular, molecular, and genetic substrates underlying the impact of nicotine on learning. Neurobiol Learn Mem 2013; 107:108-32. [PMID: 23973448 DOI: 10.1016/j.nlm.2013.08.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 08/13/2013] [Accepted: 08/13/2013] [Indexed: 12/27/2022]
Abstract
Addiction is a chronic disorder marked by long-lasting maladaptive changes in behavior and in reward system function. However, the factors that contribute to the behavioral and biological changes that occur with addiction are complex and go beyond reward. Addiction involves changes in cognitive control and the development of disruptive drug-stimuli associations that can drive behavior. A reason for the strong influence drugs of abuse can exert on cognition may be the striking overlap between the neurobiological substrates of addiction and of learning and memory, especially areas involved in declarative memory. Declarative memories are critically involved in the formation of autobiographical memories, and the ability of drugs of abuse to alter these memories could be particularly detrimental. A key structure in this memory system is the hippocampus, which is critically involved in binding multimodal stimuli together to form complex long-term memories. While all drugs of abuse can alter hippocampal function, this review focuses on nicotine. Addiction to tobacco products is insidious, with the majority of smokers wanting to quit; yet the majority of those that attempt to quit fail. Nicotine addiction is associated with the presence of drug-context and drug-cue associations that trigger drug seeking behavior and altered cognition during periods of abstinence, which contributes to relapse. This suggests that understanding the effects of nicotine on learning and memory will advance understanding and potentially facilitate treating nicotine addiction. The following sections examine: (1) how the effects of nicotine on hippocampus-dependent learning change as nicotine administration transitions from acute to chronic and then to withdrawal from chronic treatment and the potential impact of these changes on addiction, (2) how nicotine usurps the cellular mechanisms of synaptic plasticity, (3) the physiological changes in the hippocampus that may contribute to nicotine withdrawal deficits in learning, and (4) the role of genetics and developmental stage (i.e., adolescence) in these effects.
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Affiliation(s)
- Thomas J Gould
- Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States.
| | - Prescott T Leach
- Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
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Sun F, Jin K, Uteshev VV. A type-II positive allosteric modulator of α7 nAChRs reduces brain injury and improves neurological function after focal cerebral ischemia in rats. PLoS One 2013; 8:e73581. [PMID: 23951360 PMCID: PMC3739732 DOI: 10.1371/journal.pone.0073581] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/26/2013] [Indexed: 11/19/2022] Open
Abstract
In the absence of clinically-efficacious therapies for ischemic stroke there is a critical need for development of new therapeutic concepts and approaches for prevention of brain injury secondary to cerebral ischemia. This study tests the hypothesis that administration of PNU-120596, a type-II positive allosteric modulator (PAM-II) of α7 nicotinic acetylcholine receptors (nAChRs), as long as 6 hours after the onset of focal cerebral ischemia significantly reduces brain injury and neurological deficits in an animal model of ischemic stroke. Focal cerebral ischemia was induced by a transient (90 min) middle cerebral artery occlusion (MCAO). Animals were then subdivided into two groups and injected intravenously (i.v.) 6 hours post-MCAO with either 1 mg/kg PNU-120596 (treated group) or vehicle only (untreated group). Measurements of cerebral infarct volumes and neurological behavioral tests were performed 24 hrs post-MCAO. PNU-120596 significantly reduced cerebral infarct volume and improved neurological function as evidenced by the results of Bederson, rolling cylinder and ladder rung walking tests. These results forecast a high therapeutic potential for PAMs-II as effective recruiters and activators of endogenous α7 nAChR-dependent cholinergic pathways to reduce brain injury and improve neurological function after cerebral ischemic stroke.
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Affiliation(s)
- Fen Sun
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, Fort Worth, TX, United States of America
| | - Kunlin Jin
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, Fort Worth, TX, United States of America
| | - Victor V. Uteshev
- University of North Texas Health Science Center, Department of Pharmacology and Neuroscience, Fort Worth, TX, United States of America
- * E-mail:
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Lieberman JA, Dunbar G, Segreti AC, Girgis RR, Seoane F, Beaver JS, Duan N, Hosford DA. A randomized exploratory trial of an α-7 nicotinic receptor agonist (TC-5619) for cognitive enhancement in schizophrenia. Neuropsychopharmacology 2013; 38:968-75. [PMID: 23303043 PMCID: PMC3629385 DOI: 10.1038/npp.2012.259] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This exploratory trial was conducted to test the effects of an alpha7 nicotinic receptor partial agonist, TC-5619, on cognitive dysfunction and negative symptoms in subjects with schizophrenia. In the United States and India, 185 outpatients (18-60 years; male 69%; 46% tobacco users) with schizophrenia treated with quetiapine or risperidone monotherapy were randomized to 12 weeks of placebo (n=91) or TC-5619 (n=94; orally once daily 1 mg day 1 to week 4, 5 mg week 4 to 8, and 25 mg week 8 to 12). The primary efficacy outcome measure was the Groton Maze Learning Task (GMLT; executive function) of the CogState Schizophrenia Battery (CSB). Secondary outcome measures included: CSB composite score; Scale for Assessment of Negative Symptoms (SANS); Clinical Global Impression-Global Improvement (CGI-I); CGI-severity (CGI-S); and Subject Global Impression-Cognition. GMLT statistically favored TC-5619 (P=0.036) in this exploratory trial. SANS also statistically favored TC-5619 (P=0.030). No other secondary outcome measure demonstrated a drug effect in the total population; there was a statistically significant drug effect on working memory in tobacco users. The results were typically stronger in favor of TC-5619 in tobacco users and occasionally better in the United States than in India. TC-5619 was generally well tolerated with no clinically noteworthy safety findings. These results support the potential benefits of TC-5619 and alpha7 nicotinic receptor partial agonists for cognitive dysfunction and negative symptoms in schizophrenia.
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Affiliation(s)
- Jeffrey A Lieberman
- Department of Psychiatry, Columbia College of Physicians and Surgeons, New York, NY 10032, USA.
| | - Geoffrey Dunbar
- Clinical Development and Regulatory Affairs, Targacept, Winston-Salem, NC, USA
| | - Anthony C Segreti
- Clinical Development and Regulatory Affairs, Targacept, Winston-Salem, NC, USA
| | - Ragy R Girgis
- Department of Psychiatry, Columbia College of Physicians and Surgeons, New York, NY, USA
| | - Frances Seoane
- Clinical Development and Regulatory Affairs, Targacept, Winston-Salem, NC, USA
| | - Jessica S Beaver
- Clinical Development and Regulatory Affairs, Targacept, Winston-Salem, NC, USA
| | - Naihua Duan
- Department of Psychiatry, Columbia College of Physicians and Surgeons, New York, NY, USA
| | - David A Hosford
- Clinical Development and Regulatory Affairs, Targacept, Winston-Salem, NC, USA
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Nicotine restores Wt-like levels of reelin and GAD67 gene expression in brain of heterozygous reeler mice. Neurotox Res 2013; 24:205-15. [PMID: 23385624 DOI: 10.1007/s12640-013-9378-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 01/15/2013] [Accepted: 01/21/2013] [Indexed: 12/11/2022]
Abstract
Important reduction of reelin, a neural development- and plasticity-associated protein, and glutamic acid decarboxylase (GAD67) are reported in brains of schizophrenic patients. These individuals are consistently engaged in tobacco smoking and nicotine is thought to alleviate negative behavioral symptoms or cognitive alterations. In mouse brain, nicotine has been shown to reduce GAD67 promoter methylation and increase its transcription. We assessed the effects of administration of nicotine (1 mg/kg s.c.) for 6 days, in male mice heterozygous for reelin (HRM), a putative model for symptoms related to schizophrenia. Expression of reelin, GAD67 and brain-derived neurotrophic factor (BDNF) was measured in different brain areas. RNA expression analysis evidenced genotype-related changes, with a marked reduction in reelin and GAD67 gene expression in prefrontal cortex, hippocampus, cerebellum, and striatum from HRM. Nicotine treatment selectively reversed the HRM-related phenotype in most brain areas and increased BDNF gene expression in cortex and hippocampus of both genotypes. Locomotor performance in their home cage revealed that HRM subjects were characterized by general hyperactivity; with nicotine administration restoring WT-like levels of locomotion. These findings are interpreted within the hypothesis of pre-existing vulnerability (based on haploinsufficiency of reelin) to brain and behavioral disorders and regulative effects associated with nicotine exposure.
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40
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Demeter E, Sarter M. Leveraging the cortical cholinergic system to enhance attention. Neuropharmacology 2013; 64:294-304. [PMID: 22796110 PMCID: PMC3445745 DOI: 10.1016/j.neuropharm.2012.06.060] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 06/18/2012] [Accepted: 06/28/2012] [Indexed: 12/26/2022]
Abstract
Attentional impairments are found in a range of neurodegenerative and neuropsychiatric disorders. However, the development of procognitive enhancers to alleviate these impairments has been hindered by a lack of comprehensive hypotheses regarding the circuitry mediating the targeted attentional functions. Here we discuss the role of the cortical cholinergic system in mediating cue detection and attentional control and propose two target mechanisms for cognition enhancers: stimulation of prefrontal α4β2* nicotinic acetylcholine receptors (nAChR) for the enhancement of cue detection and augmentation of tonic acetylcholine levels for the enhancement of attentional control. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Elise Demeter
- Psychiatry Department, 4250 Plymouth Road, University of Michigan, Ann Arbor, MI 48109-5765, USA.
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41
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Moran VE. Cotinine: Beyond that Expected, More than a Biomarker of Tobacco Consumption. Front Pharmacol 2012; 3:173. [PMID: 23087643 PMCID: PMC3467453 DOI: 10.3389/fphar.2012.00173] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/10/2012] [Indexed: 12/15/2022] Open
Abstract
A greater incidence of tobacco consumption occurs among individuals with psychiatric conditions including post-traumatic stress disorder (PTSD), bipolar disorder, major depression, and schizophrenia, compared with the general population. Even when still controversial, it has been postulated that smoking is a form of self-medication that reduces psychiatric symptoms among individuals with these disorders. To better understand the component(s) of tobacco-inducing smoking behavior, greater attention has been directed toward nicotine. However, in recent years, new evidence has shown that cotinine, the main metabolite of nicotine, exhibits beneficial effects over psychiatric symptoms and may therefore promote smoking within this population. Some of the behavioral effects of cotinine compared to nicotine are discussed here. Cotinine, which accumulates in the body as a result of tobacco exposure, crosses the blood-brain barrier and has different pharmacological properties compared with nicotine. Cotinine has a longer plasma half-life than nicotine and showed no addictive or cardiovascular effects in humans. In addition, at the preclinical level, cotinine facilitated the extinction of fear memory and anxiety after fear conditioning, improved working memory in a mouse model of Alzheimer’s disease (AD) and in a monkey model of schizophrenia. Altogether, the new evidence suggests that the pharmacological and behavioral effects of cotinine may play a key role in promoting tobacco smoking in individuals that suffer from psychiatric conditions and represents a new potential therapeutic agent against psychiatric conditions such as AD and PTSD.
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Affiliation(s)
- Valentina Echeverria Moran
- Research and Development, Department of Veterans Affairs, Bay Pines VA Healthcare System Bay Pines, FL, USA ; Tampa VA Healthcare System Tampa, FL, USA ; Department of Molecular Medicine, University of South Florida Tampa, FL, USA
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Knott V, Shah D, Millar A, McIntosh J, Fisher D, Blais C, Ilivitsky V. Nicotine, Auditory Sensory Memory, and sustained Attention in a Human Ketamine Model of Schizophrenia: Moderating Influence of a Hallucinatory Trait. Front Pharmacol 2012; 3:172. [PMID: 23060793 PMCID: PMC3460347 DOI: 10.3389/fphar.2012.00172] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 09/04/2012] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The procognitive actions of the nicotinic acetylcholine receptor (nAChR) agonist nicotine are believed, in part, to motivate the excessive cigarette smoking in schizophrenia, a disorder associated with deficits in multiple cognitive domains, including low-level auditory sensory processes and higher-order attention-dependent operations. OBJECTIVES As N-methyl-d-aspartate receptor (NMDAR) hypofunction has been shown to contribute to these cognitive impairments, the primary aims of this healthy volunteer study were to: (a) to shed light on the separate and interactive roles of nAChR and NMDAR systems in the modulation of auditory sensory memory (and sustained attention), as indexed by the auditory event-related brain potential - mismatch negativity (MMN), and (b) to examine how these effects are moderated by a predisposition to auditory hallucinations/delusions (HD). METHODS In a randomized, double-blind, placebo-controlled design involving a low intravenous dose of ketamine (0.04 mg/kg) and a 4 mg dose of nicotine gum, MMN, and performance on a rapid visual information processing (RVIP) task of sustained attention were examined in 24 healthy controls psychometrically stratified as being lower (L-HD, n = 12) or higher (H-HD) for HD propensity. RESULTS Ketamine significantly slowed MMN, and reduced MMN in H-HD, with amplitude attenuation being blocked by the co-administration of nicotine. Nicotine significantly enhanced response speed [reaction time (RT)] and accuracy (increased % hits and d' and reduced false alarms) on the RVIP, with improved performance accuracy being prevented when nicotine was administered with ketamine. Both % hits and d', as well as RT were poorer in H-HD (vs. L-HD) and while hit rate and d' was increased by nicotine in H-HD, RT was slowed by ketamine in L-HD. CONCLUSIONS Nicotine alleviated ketamine-induced sensory memory impairment and improved attention, particularly in individuals prone to HD.
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Affiliation(s)
- Verner Knott
- Institute of Mental Health Research, University of OttawaOttawa, ON, Canada
- Neuroscience Program, Department of Cellular and Molecular Medicine, University of OttawaOttawa, ON, Canada
- School of Psychology, University of OttawaOttawa, ON, Canada
- Institute of Cognitive Science, Carleton UniversityOttawa, ON, Canada
- Royal Ottawa Mental Health CentreOttawa, ON, Canada
| | - Dhrasti Shah
- School of Psychology, University of OttawaOttawa, ON, Canada
| | - Anne Millar
- Neuroscience Program, Department of Cellular and Molecular Medicine, University of OttawaOttawa, ON, Canada
| | - Judy McIntosh
- Institute of Mental Health Research, University of OttawaOttawa, ON, Canada
| | - Derek Fisher
- Department of Psychology, Mount Saint Vincent UniversityHalifax, NS, Canada
| | - Crystal Blais
- Institute of Cognitive Science, Carleton UniversityOttawa, ON, Canada
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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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Clinically important differences in the pharmacokinetics of the ten newer "atypical" antipsychotics: Part 2. Metabolism and elimination. J Psychiatr Pract 2012; 18:361-8. [PMID: 22995963 DOI: 10.1097/01.pra.0000419820.68128.ad] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The "atypical" antipsychotics are grouped together based on what they are not (i.e., not dopamine-2 selective antagonists like haloperidol). While sharing this characteristic, these agents differ substantially in pharmacokinetics and pharmacodynamics. The first column in this series reviewed the bioavailability and half-life of the 10 newer "atypical" antipsychotics, including the most recently market- ed members of this class (asenapine, iloperidone, and lurasidone). This second column in the series discusses the metabolism of these agents, including principal enzyme(s) mediating each drug's clearance and effects of co-administering substantial CYP enzyme inhibitors. Pharmacokinetic differences among "atypical" antipsychotics can explain why some individuals may not respond to the usually effective dose of a drug, while others may be especially sensitive to its dose-dependent adverse effects. For deeper understanding of the principles behind the specifics discussed here, the concepts of "special populations" and phase I versus phase II metabolism are discussed in the introduction. An understanding of these principals and the specific pharmacokinetic differences among the "atypical" antipsychotics can help clinicians optimize drug selection and dose for specific patients under specific treatment conditions. The third column in this series will discuss the effects of hepatic and renal impairment on dosing recommendations, and a subsequent column in the series will review the substantial and clinically important pharmacodynamic differences among these agents.
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Richard MD, Brahm NC. Schizophrenia and the immune system: pathophysiology, prevention, and treatment. Am J Health Syst Pharm 2012; 69:757-66. [PMID: 22517021 DOI: 10.2146/ajhp110271] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
PURPOSE Published evidence on established and theoretical connections between immune system dysfunction and schizophrenia is reviewed, with a discussion of developments in the search for immunologically-targeted treatments. SUMMARY A growing body of evidence indicates that immunologic influences may play an important role in the etiology and course of schizophrenia. A literature search identified more than 100 articles pertaining to suspected immunologic influences on schizophrenia published over the past 15 years. Schizophrenia researchers have explored a wide range of potential immune system-related causal or contributory factors, including neurobiological and neuroanatomical disorders, genetic abnormalities, and environmental influences such as maternal perinatal infection. Efforts to establish an immunologic basis for schizophrenia and identify reliable immune markers continue to be hindered by sampling challenges and methodological problems. In aggregate, the available evidence indicates that at least some cases of schizophrenia have an immunologic component, suggesting that immune-focused prevention strategies (e.g., counseling of pregnant women to avoid immune stressors) and close monitoring of at-risk children are appropriate. While antipsychotics remain the standard treatments for schizophrenia, a variety of drugs with immunologic effects have been investigated as adjunctive therapies, with variable and sometimes conflicting results; these include the cyclooxygenase-2 inhibitor celecoxib, immune-modulating agents (e.g., azathioprine and various anticytokine agents such as atlizumab, anakinra, and tumor necrosis factor-α blockers), and an investigational anti-interferon-γ agent. CONCLUSION The published evidence indicates that immune system dysfunction related to genetic, environmental, and neurobiological influences may play a role in the etiology of schizophrenia in a subset of patients.
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Winterer G, Gallinat J, Brinkmeyer J, Musso F, Kornhuber J, Thuerauf N, Rujescu D, Favis R, Sun Y, Franc MA, Ouwerkerk-Mahadevan S, Janssens L, Timmers M, Streffer JR. Allosteric alpha-7 nicotinic receptor modulation and P50 sensory gating in schizophrenia: a proof-of-mechanism study. Neuropharmacology 2012; 64:197-204. [PMID: 22766391 DOI: 10.1016/j.neuropharm.2012.06.040] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/06/2012] [Accepted: 06/18/2012] [Indexed: 10/28/2022]
Abstract
In this multicenter, double-blind, placebo-controlled, randomized, four way cross-over proof-of-mechanism study, we tested the effect of the positive allosteric α7 nicotinic acetylcholine receptor (nAChR) modulator JNJ-39393406 in a key translational assay (sensory P50 gating) in 39 regularly smoking male patients with schizophrenia. All patients were clinically stable and JNJ-39393406 was administered as an adjunct treatment to antipsychotics. No indication was found that JNJ-39393406 has the potential to reverse basic deficits of information processing in schizophrenia (sensory P50 gating) or has a significant effect on other tested electrophysiological markers (MMN, P300 and quantitative resting EEG). Sensitivity analyses including severity of disease, baseline P50 gating, medication and gene variants of the CHRNA7 gene did not reveal any subgroups with consistent significant effects. It is discussed that potential positive effects in subgroups not present or not large enough in the current study or upon chronic dosing are possible, but unlikely to be developed. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Georg Winterer
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.
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Echeverria V, Zeitlin R. Cotinine: a potential new therapeutic agent against Alzheimer's disease. CNS Neurosci Ther 2012; 18:517-23. [PMID: 22530628 DOI: 10.1111/j.1755-5949.2012.00317.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Tobacco smoking has been correlated with a lower incidence of Alzheimer's disease (AD). This negative correlation has been attributed to nicotine's properties. However, the undesired side-effects of nicotine and the absence of clear evidence of positive effects of this drug on the cognitive abilities of AD patients have decreased the enthusiasm for its therapeutic use. In this review, we discuss evidence showing that cotinine, the main metabolite of nicotine, has many of the beneficial effects but none of the negative side-effects of its precursor. Cotinine has been shown to be neuroprotective, to improve memory in primates as well as to prevent memory loss, and to lower amyloid-beta (Aβ)) burden in AD mice. In AD, cotinine's positive effect on memory is associated with the inhibition of Aβ aggregation, the stimulation of pro-survival factors such as Akt, and the inhibition of pro-apoptotic factors such as glycogen synthase kinase 3 beta (GSK3β). Because stimulation of the α7 nicotinic acetylcholine receptors (α7nAChRs) positively modulates these factors and memory, the involvement of these receptors in cotinine's effects are discussed. Because of its beneficial effects on brain function, good safety profile, and nonaddictive properties, cotinine may represent a new therapeutic agent against AD.
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Melichercik AM, Elliott KS, Bianchi C, Ernst SM, Winters BD. Nicotinic receptor activation in perirhinal cortex and hippocampus enhances object memory in rats. Neuropharmacology 2012; 62:2096-105. [DOI: 10.1016/j.neuropharm.2012.01.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 01/11/2012] [Accepted: 01/12/2012] [Indexed: 12/22/2022]
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Kohlhaas KL, Bitner RS, Gopalakrishnan M, Rueter LE. Effects of α7 nicotinic acetylcholine receptor agonists on antipsychotic efficacy in a preclinical mouse model of psychosis. Psychopharmacology (Berl) 2012; 220:823-33. [PMID: 22038534 DOI: 10.1007/s00213-011-2535-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 10/05/2011] [Indexed: 02/04/2023]
Abstract
RATIONALE Antipsychotics normalize responses in the DBA/2 mouse model of prepulse inhibition (PPI), a preclinical model of sensorimotor gating deficits. The α7 nicotinic acetylcholine receptor (nAChR) as a molecular target is considered an attractive approach for improvement of cognitive deficits in schizophrenia (CDS). Assessment of clinical efficacy of novel agents in CDS involves treating patients already on antipsychotic medications. OBJECTIVE We evaluated the effects of the combination of α7 nAChR agonists ABT-107 (0.1-10.0 mg/kg i.p.), A-582941 (0.04-4.0 mg/kg i.p.), and PNU282987 (1.0-10.0 mg/kg i.p.) with risperidone (0.1-1.0 mg/kg i.p.) or haloperidol (0.3-3.0 mg/kg i.p.), representative atypical and typical antipsychotic agents in the DBA/2 mouse PPI model. The same α7 agonists were given alone or in combination with a dose of antipsychotic medication that induces a minimal level of catalepsy in rats, an assay with predictive validity for the induction of extrapyramidal symptoms. RESULTS The α7 nAChR agonists ABT-107, A-582941, and PNU282987 had no effect in DBA/2 mouse PPI when given alone yet increased the effects of haloperidol and risperidone. The α7 nAChR agonists did not cause catalepsy in rats, nor did they enhance antipsychotic-induced catalepsy. CONCLUSIONS When given in combination with either a typical or atypical antipsychotic, α7 nAChR agonists did not impair efficacy in the DBA/2 J mouse PPI model. The efficacy but not the motoric side effects of antipsychotics was enhanced, suggesting that adjunctive therapy of α7 nAChR agonists not only could be useful for the treatment of cognitive deficits associated with schizophrenia but also could enhance the efficacy against positive symptoms.
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Affiliation(s)
- Kathy L Kohlhaas
- Neuroscience Research, Global Pharmaceutical Research & Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL, 60064-6115, USA.
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Hall FS, Markou A, Levin ED, Uhl GR. Mouse models for studying genetic influences on factors determining smoking cessation success in humans. Ann N Y Acad Sci 2012; 1248:39-70. [PMID: 22304675 DOI: 10.1111/j.1749-6632.2011.06415.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Humans differ in their ability to quit using addictive substances, including nicotine, the major psychoactive ingredient in tobacco. For tobacco smoking, a substantial body of evidence, largely derived from twin studies, indicates that approximately half of these individual differences in ability to quit are heritable genetic influences that likely overlap with those for other addictive substances. Both twin and molecular genetic studies support overlapping influences on nicotine addiction vulnerability and smoking cessation success, although there is little formal analysis of the twin data that support this important point. None of the current datasets provides clarity concerning which heritable factors might provide robust dimensions around which individuals differ in ability to quit smoking. One approach to this problem is to test mice with genetic variations in genes that contain human variants that alter quit success. This review considers which features of quit success should be included in a comprehensive approach to elucidate the genetics of quit success, and how those features may be modeled in mice.
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Affiliation(s)
- F Scott Hall
- Molecular Neurobiology Branch, NIH-IRP, NIDA, Baltimore, Maryland 21224, USA
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