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Itokazu Y, Terry AV. Potential roles of gangliosides in chemical-induced neurodegenerative diseases and mental health disorders. Front Neurosci 2024; 18:1391413. [PMID: 38711942 PMCID: PMC11070511 DOI: 10.3389/fnins.2024.1391413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 04/12/2024] [Indexed: 05/08/2024] Open
Affiliation(s)
- Yutaka Itokazu
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Alvin V. Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA, United States
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2
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Kumro J, Tripathi A, Terry AV, Pillai A, Blake DT. α7 nicotinic acetylcholine receptors are necessary for basal forebrain activation to increase expression of the nerve growth factor receptor TrkA. bioRxiv 2024:2024.03.01.582932. [PMID: 38463995 PMCID: PMC10925259 DOI: 10.1101/2024.03.01.582932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Activation of the basal forebrain leads to increases in the expression of the nerve growth factor receptor, Tropomyosin receptor kinase A (TrkA) and decreases in expression of the beta amyloid cleavage enzyme 1 (BACE1) in the cerebral cortex of both sexes of 5xFAD mice. The studies described in this report were designed to determine if these changes were dependent on acetylcholine receptors. Mice were stimulated unilaterally in the basal forebrain for two weeks. Animals were administered a cholinergic antagonist, or saline, 30 minutes prior to stimulation. Animals administered saline exhibited significant increases in TrkA expression and decreases in BACE1 in the stimulated hemisphere relative to the unstimulated. While both nonselective nicotinic and muscarinic acetylcholine receptor blockade attenuated the BACE1 decline, only the nicotinic receptor antagonism blocked the TrkA increase. Next, we applied selective nicotinic antagonists, and the α7 antagonist blocked the TrkA increases, but the α4β2 antagonist did not. BACE1 declines were not blocked by either intervention. Mice with a loxP conditional knockout of the gene for the α7 nicotinic receptor were also employed in these studies. Animals were either stimulated bilaterally for two weeks, or left unstimulated. With or without stimulation, the expression of TrkA receptors was lower in the cortical region with the α7 nicotinic receptor knockdown. We thus conclude that α7 nicotinic receptor activation is necessary for normal expression of TrkA and increases caused by basal forebrain activation, while BACE1 declines caused by stimulation have dependency on a broader array of receptor subtypes.
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Affiliation(s)
- Jacob Kumro
- Dept Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Ashutosh Tripathi
- Dept Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, Houston, TX
| | - Alvin V Terry
- Dept Pharmacology/Toxicology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Anilkumar Pillai
- Dept Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, Augusta, GA
- Dept Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, Houston, TX
- Research and Development, Charlie Norwood VA Medical Center, Augusta, GA
| | - David T Blake
- Dept Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
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Baas PW, Sullivan KA, Terry AV, Case K, Yates PL, Sun X, Raghupathi R, Huber BR, Qiang L. Is Gulf War Illness a prolonged early phase tauopathy? Cytoskeleton (Hoboken) 2024; 81:41-46. [PMID: 37702426 PMCID: PMC10841075 DOI: 10.1002/cm.21786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/21/2023] [Accepted: 08/28/2023] [Indexed: 09/14/2023]
Abstract
The work of the Gulf War Illness (GWI) Consortium and that of basic and clinical researchers across the USA have resulted in a better understanding in recent years of the pathological basis of GWI, as well as of the mechanisms underlying the disorder. Among the most concerning symptoms suffered by veterans with GWI are cognitive decrements including those related to memory functioning. These decrements are not severe enough to meet dementia criteria, but there is significant concern that the mild cognitive impairment of these veterans will progress to dementia as they become older. Recent studies on GWI using human brain organoids as well as a rat model suggest that one potential cause of the cognitive problems may be elevated levels of tau in the brain, and this is supported by high levels of tau autoantibodies in the blood of veterans with GWI. There is urgency in finding treatments and preventive strategies for these veterans before they progress to dementia, with added value in doing so because their current status may represent an early phase of tauopathy common to many neurodegenerative diseases.
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Affiliation(s)
- Peter W. Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Kimberly A. Sullivan
- Department of Environmental Health, Boston University School of Public Health, Boston, MA, 02118, USA
| | - Alvin V. Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Kendra Case
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Philip L. Yates
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Xiaohuan Sun
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Ramesh Raghupathi
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Bertrand R. Huber
- Boston University Alzheimer’s Disease and CTE Center, Boston University School of Medicine, Boston, Massachusetts, USA; Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA; VA Boston Healthcare System, US Department of Veteran Affairs, Boston, Massachusetts, USA; Department of Veterans Affairs Medical Center, Bedford, Massachusetts, USA
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
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Burdon J, Budnik LT, Baur X, Hageman G, Howard CV, Roig J, Coxon L, Furlong CE, Gee D, Loraine T, Terry AV, Midavaine J, Petersen H, Bron D, Soskolne CL, Michaelis S. Correction: Health consequences of exposure to aircraft contaminated air and fume events: a narrative review and medical protocol for the investigation of exposed aircrew and passengers. Environ Health 2023; 22:75. [PMID: 37891661 PMCID: PMC10612331 DOI: 10.1186/s12940-023-01025-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2023]
Affiliation(s)
- Jonathan Burdon
- Respiratory Physician, St Vincent's Private Hospital, East Melbourne, Australia
| | - Lygia Therese Budnik
- Institute for Occupational and Maritime Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Xaver Baur
- European Society for Environmental and Occupational Medicine, Berlin, Germany
- University of Hamburg, Hamburg, Germany
| | - Gerard Hageman
- Department of Neurology, Medisch Spectrum Twente, Hospital Enschede, Enschede, The Netherlands
| | - C Vyvyan Howard
- Centre for Molecular Biosciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Jordi Roig
- Department of Pulmonary Medicine, Cl?nica Creu Blanca, Barcelona, Spain
| | - Leonie Coxon
- Clinical and Forensic Psychologist, Mount Pleasant Psychology, Perth, Australia
| | - Clement E Furlong
- Departments of Medicine (Div. Medical Genetics) and Genome Sciences, University of Washington, Seattle, USA
| | - David Gee
- Centre for Pollution Research and Policy, Visiting Fellow, Brunel University, London, UK
| | - Tristan Loraine
- Technical Consultant, Spokesperson for the Global Cabin Air Quality Executive, London, UK
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, USA
| | | | - Hannes Petersen
- Faculty of Medicine, University of Iceland, Akureyri Hospital, Akureyri, Iceland
| | - Denis Bron
- Federal Department of Defence, Civil Protection and Sport (DDPS), Aeromedical Institute (FAI)/AeMC, Air Force, D?bendorf, Switzerland
| | - Colin L Soskolne
- School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Susan Michaelis
- Occupational and Environmental Health Research Group, Honorary Senior Research Fellow, University of Stirling, Scotland / Michaelis Aviation Consulting, West Sussex, England.
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Burdon J, Budnik LT, Baur X, Hageman G, Howard CV, Roig J, Coxon L, Furlong CE, Gee D, Loraine T, Terry AV, Midavaine J, Petersen H, Bron D, Soskolne CL, Michaelis S. Health consequences of exposure to aircraft contaminated air and fume events: a narrative review and medical protocol for the investigation of exposed aircrew and passengers. Environ Health 2023; 22:43. [PMID: 37194087 PMCID: PMC10186727 DOI: 10.1186/s12940-023-00987-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/31/2023] [Indexed: 05/18/2023]
Abstract
Thermally degraded engine oil and hydraulic fluid fumes contaminating aircraft cabin air conditioning systems have been well documented since the 1950s. Whilst organophosphates have been the main subject of interest, oil and hydraulic fumes in the air supply also contain ultrafine particles, numerous volatile organic hydrocarbons and thermally degraded products. We review the literature on the effects of fume events on aircrew health. Inhalation of these potentially toxic fumes is increasingly recognised to cause acute and long-term neurological, respiratory, cardiological and other symptoms. Cumulative exposure to regular small doses of toxic fumes is potentially damaging to health and may be exacerbated by a single higher-level exposure. Assessment is complex because of the limitations of considering the toxicity of individual substances in complex heated mixtures.There is a need for a systematic and consistent approach to diagnosis and treatment of persons who have been exposed to toxic fumes in aircraft cabins. The medical protocol presented in this paper has been written by internationally recognised experts and presents a consensus approach to the recognition, investigation and management of persons suffering from the toxic effects of inhaling thermally degraded engine oil and other fluids contaminating the air conditioning systems in aircraft, and includes actions and investigations for in-flight, immediately post-flight and late subsequent follow up.
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Affiliation(s)
- Jonathan Burdon
- Respiratory Physician, St Vincent's Private Hospital, East Melbourne, Australia
| | - Lygia Therese Budnik
- Institute for Occupational and Maritime Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Xaver Baur
- European Society for Environmental and Occupational Medicine, Berlin, Germany
- University of Hamburg, Hamburg, Germany
| | - Gerard Hageman
- Department of Neurology, Medisch Spectrum Twente, Hospital Enschede, Enschede, The Netherlands
| | - C Vyvyan Howard
- Centre for Molecular Biosciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Jordi Roig
- Department of Pulmonary Medicine, Clínica Creu Blanca, Barcelona, Spain
| | - Leonie Coxon
- Clinical and Forensic Psychologist, Mount Pleasant Psychology, Perth, Australia
| | - Clement E Furlong
- Departments of Medicine (Div. Medical Genetics) and Genome Sciences, University of Washington, Seattle, USA
| | - David Gee
- Centre for Pollution Research and Policy, Visiting Fellow, Brunel University, London, UK
| | - Tristan Loraine
- Technical Consultant, Spokesperson for the Global Cabin Air Quality Executive, London, UK
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, USA
| | | | - Hannes Petersen
- Faculty of Medicine, University of Iceland, Akureyri Hospital, Akureyri, Iceland
| | - Denis Bron
- Federal Department of Defence, Civil Protection and Sport (DDPS), Aeromedical Institute (FAI)/AeMC, Air Force, Dübendorf, Switzerland
| | - Colin L Soskolne
- School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Susan Michaelis
- Occupational and Environmental Health Research Group, Honorary Senior Research Fellow, University of Stirling, Scotland / Michaelis Aviation Consulting, West Sussex, England.
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Terry AV, Jones K, Bertrand D. Nicotinic acetylcholine receptors in neurological and psychiatric diseases. Pharmacol Res 2023; 191:106764. [PMID: 37044234 DOI: 10.1016/j.phrs.2023.106764] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/30/2023] [Accepted: 04/07/2023] [Indexed: 04/14/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that are widely distributed both pre- and post-synaptically in the mammalian brain. By modulating cation flux across cell membranes, neuronal nAChRs regulate neuronal excitability and the release of a variety of neurotransmitters to influence multiple physiologic and behavioral processes including synaptic plasticity, motor function, attention, learning and memory. Abnormalities of neuronal nAChRs have been implicated in the pathophysiology of neurologic disorders including Alzheimer's disease, Parkinson's disease, epilepsy, and Tourette´s syndrome, as well as psychiatric disorders including schizophrenia, depression, and anxiety. The potential role of nAChRs in a particular illness may be indicated by alterations in the expression of nAChRs in relevant brain regions, genetic variability in the genes encoding for nAChR subunit proteins, and/or clinical or preclinical observations where specific ligands showed a therapeutic effect. Over the past 25 years, extensive preclinical and some early clinical evidence suggested that ligands at nAChRs might have therapeutic potential for neurologic and psychiatric disorders. However, to date the only approved indications for nAChR ligands are smoking cessation and the treatment of dry eye disease. It has been argued that progress in nAChR drug discovery has been limited by translational gaps between the preclinical models and the human disease as well as unresolved questions regarding the pharmacological goal (i.e., agonism, antagonism or receptor desensitization) depending on the disease.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912.
| | - Keri Jones
- Educational Innovation Institute, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912
| | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222 Vésenaz, Geneva, Switzerland
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Terry AV, Beck WD, Lin PC, Callahan PM, Rudic RD, Hamrick MW. Manganese-enhanced magnetic resonance imaging method detects age-related impairments in axonal transport in mice and attenuation of the impairments by a microtubule-stabilizing compound. Brain Res 2022; 1789:147947. [PMID: 35597325 DOI: 10.1016/j.brainres.2022.147947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/18/2022] [Accepted: 05/15/2022] [Indexed: 11/02/2022]
Abstract
In this study a manganese-enhanced magnetic resonance imaging (MEMRI) method was developed for mice for measuring axonal transport (AXT) rates in real time in olfactory receptor neurons, which project from the olfactory epithelium to the olfactory neuronal layer of the olfactory bulb. Using this MEMRI method, two major experiments were conducted: 1) an evaluation of the effects of age on AXT rates and 2) an evaluation of the brain-penetrant, microtubule-stabilizing agent, Epothilone D for effect on AXT rates in aged mice. In these studies, we improved upon previous MEMRI approaches to develop a method where real-time measurements (32 time points) of AXT rates in mice can be determined over a single (approximately 100 min) scanning session. In the age comparisons, AXT rates were significantly higher in young (mean age ∼4.0 months old) versus aged (mean age ∼24.5 months old) mice. Moreover, in aged mice, eight weeks of treatment with Epothilone D, (0.3 and 1.0 mg/kg) was associated with statistically significant increases in AXT rates compared to vehicle-treated subjects. These experiments conducted in a living mammalian model (i.e., wild type, C57BL/6 mice), using a new modified MEMRI method, thus provide further evidence that the process of aging leads to decreases in AXT rates in the brain and they further support the argument that microtubule-based therapeutic strategies designed to improve AXT rates have potential for age-related neurological disorders.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States.
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
| | - Ping-Chang Lin
- Research Computing Center, University of Chicago, Chicago, IL 60637, United States
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
| | - R Daniel Rudic
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
| | - Mark W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States
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Chu X, Subramani K, Thomas B, Terry AV, Fulzele S, Raju RP. Juvenile Plasma Factors Improve Organ Function and Survival following Injury by Promoting Antioxidant Response. Aging Dis 2022; 13:568-582. [PMID: 35371607 PMCID: PMC8947827 DOI: 10.14336/ad.2021.0830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 08/30/2021] [Indexed: 11/01/2022] Open
Abstract
Studies have shown that factors in the blood of young organisms can rejuvenate the old ones. Studies using heterochronic parabiosis models further reinforced the hypothesis that juvenile factors can rejuvenate aged systems. We sought to determine the effect of juvenile plasma-derived factors on the outcome following hemorrhagic shock injury in aged mice. We discovered that pre-pubertal (young) mice subjected to hemorrhagic shock survived for a prolonged period, in the absence of fluid resuscitation, compared to mature or aged mice. To further understand the mechanism of maturational dependence of injury resolution, extracellular vesicles isolated from the plasma of young mice were administered to aged mice subjected to hemorrhagic shock. The extracellular vesicle treatment prolonged life in the aged mice. The treatment resulted in reduced oxidative stress in the liver and in the circulation, along with an enhanced expression of the nuclear factor erythroid factor 2-related factor 2 (Nrf2) and its target genes, and a reduction in the expression of the transcription factor BTB and CNC homology 1 (Bach1). We propose that plasma factors in the juvenile mice have a reparative effect in the aged mice in injury resolution by modulating the Nrf2/Bach1 axis in the antioxidant response pathway.
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Affiliation(s)
- Xiaogang Chu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA.
| | - Kumar Subramani
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA.
| | - Bobby Thomas
- Departments of Pediatrics, Neuroscience and Drug Discovery, Darby Children’s Research Institute, Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA.
| | - Sadanand Fulzele
- Department of Medicine, Medical College of Georgia, Augusta, GA 30912, USA.
| | - Raghavan Pillai Raju
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA.
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Yates PL, Patil A, Sun X, Niceforo A, Gill R, Callahan P, Beck W, Piermarini E, Terry AV, Sullivan KA, Baas PW, Qiang L. A cellular approach to understanding and treating Gulf War Illness. Cell Mol Life Sci 2021; 78:6941-6961. [PMID: 34580742 DOI: 10.1007/s00018-021-03942-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/30/2021] [Accepted: 09/14/2021] [Indexed: 01/04/2023]
Abstract
Gulf War Illness (GWI), a disorder suffered by approximately 200,000 veterans of the first Gulf War, was caused by exposure to low-level organophosphate pesticides and nerve agents in combination with battlefield stress. To elucidate the mechanistic basis of the brain-related symptoms of GWI, human-induced pluripotent stem cells (hiPSCs) derived from veterans with or without GWI were differentiated into forebrain glutamatergic neurons and then exposed to a Gulf War (GW) relevant toxicant regimen consisting of a sarin analog and cortisol, a human stress hormone. Elevated levels of total and phosphorylated tau, reduced microtubule acetylation, altered mitochondrial dynamics/transport, and decreased neuronal activity were observed in neurons exposed to the toxicant regimen. Some of the data are consistent with the possibility that some veterans may have been predisposed to acquire GWI. Wistar rats exposed to a similar toxicant regimen showed a mild learning and memory deficit, as well as cell loss and tau pathology selectively in the CA3 region of the hippocampus. These cellular responses offer a mechanistic explanation for the memory loss suffered by veterans with GWI and provide a cell-based model for screening drugs and developing personalized therapies for these veterans.
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Affiliation(s)
- Philip L Yates
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Ankita Patil
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Xiaohuan Sun
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Alessia Niceforo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Ramnik Gill
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Patrick Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Wayne Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Emanuela Piermarini
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Kimberly A Sullivan
- Department of Environmental Health, Boston University School of Public Health, Boston, MA, 02118, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA.
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Abstract
Gulf War Illness (GWI) is estimated to have affected about one third of the Veterans who participated in the first Persian Gulf War. The symptoms of GWI include chronic neurologic impairments, chronic fatigue syndrome, as well as fibromyalgia and immune system disorders, collectively referred to as chronic multi-symptom illness. Thirty years after the war, we still do not have an effective treatment for GWI. It is necessary to understand the molecular basis of the symptoms of GWI in order to develop appropriate therapeutic strategies. Cellular energetics are critical to the maintenance of cellular homeostasis, a process that is highly dependent on intact mitochondrial function and there is significant evidence from both human studies and animal models that mitochondrial impairments may lead to GWI symptoms. The available clinical and pre-clinical data suggest that agents that improve mitochondrial function have the potential to restore cellular energetics and treat GWI. To date, the experiments conducted in animal models of GWI have mainly focused on neurobehavioral aspects of the illness. Additional studies to address the fundamental biological processes that trigger the dysregulation of cellular energetics in GWI are warranted to better understand the underlying pathology and to develop new treatment methods. This review highlights studies related to mitochondrial dysfunction observed in both GW veterans and in animal models of GWI.
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Affiliation(s)
- Raghavan Pillai Raju
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States.
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States
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Naughton SX, Beck WD, Wei Z, Wu G, Baas PW, Terry AV. The Carbamate, Physostigmine does not Impair Axonal Transport in Rat Cortical Neurons. Neurosci Insights 2021; 16:26331055211020289. [PMID: 34104889 PMCID: PMC8155748 DOI: 10.1177/26331055211020289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/07/2021] [Indexed: 11/21/2022] Open
Abstract
Among the various chemicals that are commonly used as pesticides,
organophosphates (OPs), and to a lesser extent, carbamates, are most frequently
associated with adverse long-term neurological consequences. OPs and the
carbamate, pyridostigmine, used as a prophylactic drug against potential nerve
agent attacks, have also been implicated in Gulf War Illness (GWI), which is
often characterized by chronic neurological symptoms. While most OP- and
carbamate-based pesticides, and pyridostigmine are relatively potent
acetylcholinesterase inhibitors (AChEIs), this toxicological mechanism is
inadequate to explain their long-term health effects, especially when no signs
of acute cholinergic toxicity are exhibited. Our previous work suggests that a
potential mechanism of the long-term neurological deficits associated with OPs
is impairment of axonal transport (AXT); however, we had not previously
evaluated carbamates for this effect. Here we thus evaluated the carbamate,
physostigmine (PHY), a highly potent AChEI, on AXT using an in
vitro neuronal live imaging assay that we have previously found to
be very sensitive to OP-related deficits in AXT. We first evaluated the OP,
diisopropylfluorophosphate (DFP) (concentration range 0.001-10.0 µM) as a
reference compound that we found previously to impair AXT and subsequently
evaluated PHY (concentration range 0.01-100 nM). As expected, DFP impaired AXT
in a concentration-dependent manner, replicating our previously published
results. In contrast, none of the concentrations of PHY (including
concentrations well above the threshold for impairing AChE) impaired AXT. These
data suggest that the long-term neurological deficits associated with some
carbamates are not likely due to acute impairments of AXT.
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Affiliation(s)
- Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, PA, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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Plagenhoef MR, Callahan PM, Beck WD, Blake DT, Terry AV. Aged rhesus monkeys: Cognitive performance categorizations and preclinical drug testing. Neuropharmacology 2021; 187:108489. [PMID: 33561449 PMCID: PMC8286428 DOI: 10.1016/j.neuropharm.2021.108489] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 12/24/2022]
Abstract
Rodent models have facilitated major discoveries in neurobiology, however, the low success rate of novel medications in clinical trials have led to questions about their translational value in neuropsychiatric drug development research. For age-related disorders of cognition such as Alzheimer' disease (AD) there is interest in moving beyond transgenic amyloid-β and/or tau-expressing rodent models and focusing more on natural aging and dissociating "healthy" from "pathological" aging to identify new therapeutic targets and treatments. In complex disorders such as AD, it can also be argued that animals with closer neurobiology to humans (e.g., nonhuman primates) should be employed more often particularly in the later phases of drug development. The purpose of the work described here was to evaluate the cognitive capabilities of rhesus monkeys across a wide range of ages in different delayed response tasks, a computerized delayed match to sample (DMTS) task and a manual delayed match to position (DMTP) task. Based on specific performance criteria and comparisons to younger subjects, the older subjects were generally less proficient, however, some performed as well as young subjects, while other aged subjects were markedly impaired. Accordingly, the older subjects could be categorized as aged "cognitively-unimpaired" or aged "cognitively-impaired" with a third group (aged-other) falling in between. Finally, as a proof of principle, we demonstrated using the DMTP task that aged cognitively-impaired monkeys are sensitive to the pro-cognitive effects of a nicotinic acetylcholine receptor (nAChR) partial agonist, encenicline, suggesting that nAChR ligands remain viable as potential treatments for age-related disorders of cognition.
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Affiliation(s)
- Marc R Plagenhoef
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - David T Blake
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia.
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13
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Gao J, Suo C, Tseng JH, Moss MA, Terry AV, Chapman J. Design and Synthesis of Ranitidine Analogs as Multi-Target Directed Ligands for the Treatment of Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22063120. [PMID: 33803769 PMCID: PMC8003314 DOI: 10.3390/ijms22063120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/08/2021] [Accepted: 03/16/2021] [Indexed: 01/03/2023] Open
Abstract
The aggregation of amyloid β (Aβ) peptides and deposition of amyloid plaques are implicated in the pathogenesis of Alzheimer’s disease (AD). Therefore, blocking Aβ aggregation with small molecules has been proposed as one therapeutic approach for AD. In the present study, a series of ranitidine analogs containing cyclic imide isosteres were synthesized and their inhibitory activities toward Aβ aggregation were evaluated using in vitro thioflavin T assays. The structure–activity relationship revealed that the 1,8-naphthalimide moiety provided profound inhibition of Aβ aggregation and structural modifications on the other parts of the parent molecule (compound 6) maintained similar efficacy. Some of these ranitidine analogs also possessed potent inhibitory activities of acetylcholinesterase (AChE), which is another therapeutic target in AD. These ranitidine analogs, by addressing both Aβ aggregation and AChE, offer insight into the key chemical features of a new type of multi-target directed ligands for the pharmaceutical treatment of AD.
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Affiliation(s)
- Jie Gao
- Department of Clinical and Diagnostic Science, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Correspondence:
| | - Chen Suo
- Department of Chemical Engineering and Biomedical Engineering, University of South Carolina, Columbia, SC 29208, USA; (C.S.); (J.-H.T.); (M.A.M.)
| | - Jui-Heng Tseng
- Department of Chemical Engineering and Biomedical Engineering, University of South Carolina, Columbia, SC 29208, USA; (C.S.); (J.-H.T.); (M.A.M.)
| | - Melissa A. Moss
- Department of Chemical Engineering and Biomedical Engineering, University of South Carolina, Columbia, SC 29208, USA; (C.S.); (J.-H.T.); (M.A.M.)
| | - Alvin V. Terry
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA 30912, USA;
| | - James Chapman
- Department of Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC 29208, USA;
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14
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Naughton SX, Beck WD, Wei Z, Wu G, Terry AV. Corrigendum to "Multifunctional compounds lithium chloride and methylene Blue attenuate the negative effects of diisopropylfluorophosphate on axonal transport in rat cortical neurons" [Toxicology 431 (2020): 152379]. Toxicology 2021; 453:152745. [PMID: 33685755 DOI: 10.1016/j.tox.2021.152745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia.
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15
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Wei Z, Xu X, Fang Y, Khater M, Naughton SX, Hu G, Terry AV, Wu G. Rab43 GTPase directs postsynaptic trafficking and neuron-specific sorting of G protein-coupled receptors. J Biol Chem 2021; 296:100517. [PMID: 33676895 PMCID: PMC8050390 DOI: 10.1016/j.jbc.2021.100517] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/25/2021] [Accepted: 03/03/2021] [Indexed: 12/31/2022] Open
Abstract
G protein–coupled receptors (GPCRs) are important modulators of synaptic functions. A fundamental but poorly addressed question in neurobiology is how targeted GPCR trafficking is achieved. Rab GTPases are the master regulators of vesicle-mediated membrane trafficking, but their functions in the synaptic presentation of newly synthesized GPCRs are virtually unknown. Here, we investigate the role of Rab43, via dominant-negative inhibition and CRISPR–Cas9–mediated KO, in the export trafficking of α2-adrenergic receptor (α2-AR) and muscarinic acetylcholine receptor (mAChR) in primary neurons and cells. We demonstrate that Rab43 differentially regulates the overall surface expression of endogenous α2-AR and mAChR, as well as their signaling, in primary neurons. In parallel, Rab43 exerts distinct effects on the dendritic and postsynaptic transport of specific α2B-AR and M3 mAChR subtypes. More interestingly, the selective actions of Rab43 toward α2B-AR and M3 mAChR are neuronal cell specific and dictated by direct interaction. These data reveal novel, neuron-specific functions for Rab43 in the dendritic and postsynaptic targeting and sorting of GPCRs and imply multiple forward delivery routes for different GPCRs in neurons. Overall, this study provides important insights into regulatory mechanisms of GPCR anterograde traffic to the functional destination in neurons.
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Affiliation(s)
- Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Yinquan Fang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA; Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Mostafa Khater
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Gang Hu
- Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.
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16
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Poddar I, Callahan PM, Hernandez CM, Pillai A, Yang X, Bartlett MG, Terry AV. Oral quetiapine treatment results in time-dependent alterations of recognition memory and brain-derived neurotrophic factor-related signaling molecules in the hippocampus of rats. Pharmacol Biochem Behav 2020; 197:172999. [PMID: 32702397 DOI: 10.1016/j.pbb.2020.172999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/13/2020] [Accepted: 07/13/2020] [Indexed: 11/16/2022]
Abstract
Antipsychotic drugs (APDs) have a variety of important therapeutic applications for neuropsychiatric disorders. However, they are routinely prescribed off-label across all age categories, a controversial practice given their potential for producing metabolic and extrapyramidal side effects. Evidence also suggests that chronic treatment with some APDs may lead to impairments in cognition and decreases in brain volume, although these findings are controversial. The purpose of the studies described here was to evaluate one of the most commonly prescribed APDs, quetiapine, for chronic effects on recognition memory, brain-derived neurotrophic factor (BDNF), its precursor proBDNF, as well as relevant downstream signaling molecules that are known to influence neuronal plasticity and cognition. Multiple cohorts of adult rats were treated with quetiapine (25.0 mg/kg/day) for 30 or 90 days in their drinking water then evaluated for drug effects on motor function in a catalepsy assessment, recognition memory in a spontaneous novel object recognition (NOR) task, and BDNF-related signaling molecules in the post mortem hippocampus via Western Blot. The results indicated that oral quetiapine at a dose that did not induce catalepsy, led to time-dependent impairments in NOR performance, increases in the proBDNF/BDNF ratio, and decreases in Akt and CREB phosphorylation in the hippocampus. These results indicate that chronic treatment with quetiapine has the potential to adversely affect recognition memory and neurotrophin-related signaling molecules that support synaptic plasticity and cognitive function. Given the widespread use this APD across multiple conditions and patient populations, such long-term effects observed in animals should be considered.
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Affiliation(s)
- Indrani Poddar
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America; Small Animal Behavior Core, Augusta University, Augusta, GA 30912, United States of America
| | - Caterina M Hernandez
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Anilkumar Pillai
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA 30602, United States of America
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA 30602, United States of America
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America; Small Animal Behavior Core, Augusta University, Augusta, GA 30912, United States of America.
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17
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Callahan PM, Terry AV, Nelson FR, Volkmann RA, Vinod AB, Zainuddin M, Menniti FS. Modulating inhibitory response control through potentiation of GluN2D subunit-containing NMDA receptors. Neuropharmacology 2020; 173:107994. [PMID: 32057801 DOI: 10.1016/j.neuropharm.2020.107994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 01/16/2020] [Accepted: 02/05/2020] [Indexed: 01/15/2023]
Abstract
NMDA receptors containing GluN2D subunits are expressed in the subthalamic nucleus and external globus pallidus, key nuclei of the indirect and hyperdirect pathways of the basal ganglia. This circuitry integrates cortical input with dopaminergic signaling to select advantageous behaviors among available choices. In the experiments described here, we characterized the effects of PTC-174, a novel positive allosteric modulator (PAM) of GluN2D subunit-containing NMDA receptors, on response control regulated by this circuitry. The indirect pathway suppresses less advantageous behavioral choices, a manifestation of which is suppression of locomotor activity in rats. Systemic administration of PTC-174 produced a dose-dependent reduction in activity in rats placed in a novel open field or administered the stimulants MK-801 or amphetamine. The hyperdirect pathway controls release of decisions from the basal ganglia to the cortex to optimize choice processing. Such response control was modeled in rats as premature responding in the 5-choice serial reaction time (5-CSRT) task. PTC-174 produced a dose-dependent reduction in premature responding in this task. These data suggest that potentiation of GluN2D receptor activity by PTC-174 facilitates the complex basal ganglia information processing that underlies response control. The behavioral effects occurred at estimated free PTC-174 brain concentrations predicted to induce 10-50% increases in GluN2D activity. The present findings suggest the potential of GluN2D PAMs to modulate basal ganglia function and to treat neurological disorders related to dysfunctional response control.
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Affiliation(s)
- Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA; Small Animal Behavior Core, Augusta University, Augusta, GA, 30912, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA; Small Animal Behavior Core, Augusta University, Augusta, GA, 30912, USA
| | | | | | - A B Vinod
- Jubilant Biosys Ltd, Yeshwantpur, Bangalore, 560022, Karnataka, India
| | - Mohd Zainuddin
- Jubilant Biosys Ltd, Yeshwantpur, Bangalore, 560022, Karnataka, India
| | - Frank S Menniti
- The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, 02881, USA.
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18
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Wei Z, Naughton SX, Terry AV, Wu G. Dissection of anterograde trafficking and sorting of GPCRs in primary neurons. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.04122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Terry AV, Callahan PM. α7 nicotinic acetylcholine receptors as therapeutic targets in schizophrenia: Update on animal and clinical studies and strategies for the future. Neuropharmacology 2020; 170:108053. [PMID: 32188568 DOI: 10.1016/j.neuropharm.2020.108053] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 10/24/2022]
Abstract
Schizophrenia is a devastating mental illness and its effective treatment is among the most challenging issues in psychiatry. The symptoms of schizophrenia are heterogeneous ranging from positive symptoms (e.g., delusions, hallucinations) to negative symptoms (e.g., anhedonia, social withdrawal) to cognitive dysfunction. Antipsychotics are effective at ameliorating positive symptoms in some patients; however, they are not reliably effective at improving the negative symptoms or cognitive impairments. The inability to address the cognitive impairments is a particular concern since they have the greatest long-term impact on functional outcomes. While decades of research have been devoted to the development of pro-cognitive agents for schizophrenia, to date, no drug has been approved for clinical use. Converging behavioral, neurobiological, and genetic evidence led to the identification of the α7-nicotinic acetylcholine receptor (α7-nAChR) as a therapeutic target several years ago and there is now extensive preclinical evidence that α7-nAChR ligands have pro-cognitive effects and other properties that should be beneficial to schizophrenia patients. However, like the other pro-cognitive strategies, no α7-nAChR ligand has been approved for clinical use in schizophrenia thus far. In this review, several topics are discussed that may impact the success of α7-nAChR ligands as pro-cognitive agents for schizophrenia including the translational value of the animal models used, clinical trial design limitations, confounding effects of polypharmacy, dose-effect relationships, and chronic versus intermittent dosing considerations. Determining the most optimal pharmacologic strategy at α7-nAChRs: agonist, positive allosteric modulator, or potentially even receptor antagonist is also discussed. article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia; Small Animal Behavior Core, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia.
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia; Small Animal Behavior Core, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
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20
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Poddar I, Callahan PM, Hernandez CM, Pillai A, Yang X, Bartlett MG, Terry AV. Chronic oral treatment with risperidone impairs recognition memory and alters brain-derived neurotrophic factor and related signaling molecules in rats. Pharmacol Biochem Behav 2020; 189:172853. [PMID: 31945381 DOI: 10.1016/j.pbb.2020.172853] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/09/2020] [Accepted: 01/12/2020] [Indexed: 01/09/2023]
Abstract
Antipsychotic drugs (APDs) are essential for the treatment of schizophrenia and other neuropsychiatric illnesses such as bipolar disease. However, they are also extensively prescribed off-label for many other conditions, a practice that is controversial given their potential for long-term side effects. There is clinical and preclinical evidence that chronic treatment with some APDs may lead to impairments in cognition and decreases in brain volume, although the molecular mechanisms of these effects are unknown. The purpose of the rodent studies described here was to evaluate a commonly prescribed APD, risperidone, for chronic effects on recognition memory, brain-derived neurotrophic factor (BDNF), its precursor proBDNF, as well as relevant downstream signaling molecules that are known to influence neuronal plasticity and cognition. Multiple cohorts of adult rats were treated with risperidone (2.5 mg/kg/day) or vehicle (dilute acetic acid solution) in their drinking water for 30 or 90 days. Subjects were then evaluated for drug effects on recognition memory in a spontaneous novel object recognition task and protein levels of BDNF-related signaling molecules in the hippocampus and prefrontal cortex. The results indicated that depending on the treatment period, a therapeutically relevant daily dose of risperidone impaired recognition memory and increased the proBDNF/BDNF ratio in the hippocampus and prefrontal cortex. Risperidone treatment also led to a decrease in Akt and CREB phosphorylation in the prefrontal cortex. These results indicate that chronic treatment with a commonly prescribed APD, risperidone, has the potential to adversely affect recognition memory and neurotrophin-related signaling molecules that support synaptic plasticity and cognitive function.
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Affiliation(s)
- Indrani Poddar
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America.; Small Animal Behavior Core, Augusta University, Augusta, GA 30912, United States of America
| | - Caterina M Hernandez
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Anilkumar Pillai
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA 30607, United States of America
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA 30607, United States of America
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America.; Small Animal Behavior Core, Augusta University, Augusta, GA 30912, United States of America.
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Callahan PM, Plagenhoef MR, Blake DT, Terry AV. Atomoxetine improves memory and other components of executive function in young-adult rats and aged rhesus monkeys. Neuropharmacology 2019; 155:65-75. [PMID: 31108108 PMCID: PMC6839761 DOI: 10.1016/j.neuropharm.2019.05.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/26/2019] [Accepted: 05/13/2019] [Indexed: 02/04/2023]
Abstract
Atomoxetine is a norepinephrine reuptake inhibitor and FDA-approved treatment for attention deficit/hyperactivity disorder (ADHD) in children, adolescents, and adults. While there is some evidence that atomoxetine may improve additional domains of cognition beyond attention in both young adults and aged individuals, this subject has not been extensively investigated. Here, we evaluated atomoxetine (in low mg/kg doses) in a variable stimulus duration (vSD) and a variable intertrial interval (vITI) version of the five choice-serial reaction time task (5C-SRTT), and an eight-arm radial arm maze (RAM) procedure in young-adult rats. The compound was further evaluated (in μg/kg-low mg/kg doses) along with nicotine (as a reference compound) and the Alzheimer's disease treatment donepezil in a distractor version of a delayed match to sample task (DMTS-D) in aged monkeys (mean age = 21.8 years). Atomoxetine (depending on the dose) improved accuracy (sustained attention) as well as behaviors related to impulsivity, compulsivity and cognitive inflexibility in both the vSD and vITI tasks and it improved spatial reference memory in the RAM. In the DMTS-D task, both nicotine and atomoxetine, but not donepezil attenuated the effects of the distractor on accuracy at short delays (non-spatial working/short term memory). However, combining sub-effective doses of atomoxetine and donepezil did enhance DMTS-D accuracy indicating the potential of using atomoxetine as an adjunctive treatment with donepezil. Collectively, these animal studies support the further evaluation of atomoxetine as a repurposed drug for younger adults as well older individuals who suffer from deficits in attention, memory and other components of executive function.
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Affiliation(s)
- Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Marc R Plagenhoef
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - David T Blake
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia.
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22
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Naughton SX, Wei Z, Guangyu W, Terry AV. Kinase and Mitochondrial Targets for Reversing the Adverse Effects of Organophosphates on Axonal Transport. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.813.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Zhe Wei
- Medical College of GeorgiaAugusta UniversityAugustaGA
| | - Wu Guangyu
- Medical College of GeorgiaAugusta UniversityAugustaGA
| | - Alvin V Terry
- Medical College of GeorgiaAugusta UniversityAugustaGA
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23
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Terry AV, Callahan PM. Nicotinic Acetylcholine Receptor Ligands, Cognitive Function, and Preclinical Approaches to Drug Discovery. Nicotine Tob Res 2019; 21:383-394. [PMID: 30137518 PMCID: PMC6379039 DOI: 10.1093/ntr/nty166] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 08/20/2018] [Indexed: 12/15/2022]
Abstract
Interest in nicotinic acetylcholine receptor (nAChR) ligands as potential therapeutic agents for cognitive disorders began more than 30 years ago when it was first demonstrated that the tobacco alkaloid nicotine could improve cognitive function in nicotine-deprived smokers as well as nonsmokers. Numerous animal and human studies now indicate that nicotine and a variety of nAChR ligands have the potential to improve multiple domains of cognition including attention, spatial learning, working memory, recognition memory, and executive function. The purpose of this review is to (1) discuss several pharmacologic strategies that have been developed to enhance nAChR activity (eg, agonist, partial agonist, and positive allosteric modulator) and improve cognitive function, (2) provide a brief overview of some of the more common rodent behavioral tasks with established translational validity that have been used to evaluate nAChR ligands for effects on cognitive function, and (3) briefly discuss some of the topics of debate regarding the development of optimal therapeutic strategies using nAChR ligands. Because of their densities in the mammalian brain and the amount of literature available, the review primarily focuses on ligands of the high-affinity α4β2* nAChR ("*" indicates the possible presence of additional subunits in the complex) and the low-affinity α7 nAChR. The behavioral task discussion focuses on representative methods that have been designed to model specific domains of cognition that are relevant to human neuropsychiatric disorders and often evaluated in human clinical trials. IMPLICATIONS The preclinical literature continues to grow in support of the development of nAChR ligands for a variety of illnesses that affect humans. However, to date, no new nAChR ligand has been approved for any condition other than nicotine dependence. As discussed in this review, the studies conducted to date provide the impetus for continuing efforts to develop new nAChR strategies (ie, beyond simple agonist and partial agonist approaches) as well as to refine current behavioral strategies and create new animal models to address translational gaps in the drug discovery process.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA
- Small Animal Behavior Core Laboratory, Augusta University, Augusta, GA
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA
- Small Animal Behavior Core Laboratory, Augusta University, Augusta, GA
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24
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Crider A, Nelson T, Davis T, Fagan K, Vaibhav K, Luo M, Kamalasanan S, Terry AV, Pillai A. Estrogen Receptor β Agonist Attenuates Endoplasmic Reticulum Stress-Induced Changes in Social Behavior and Brain Connectivity in Mice. Mol Neurobiol 2018; 55:7606-7618. [PMID: 29430617 PMCID: PMC6070416 DOI: 10.1007/s12035-018-0929-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/24/2018] [Indexed: 11/26/2022]
Abstract
Impaired social interaction is a key feature of several major psychiatric disorders including depression, autism, and schizophrenia. While, anatomically, the prefrontal cortex (PFC) is known as a key regulator of social behavior, little is known about the cellular mechanisms that underlie impairments of social interaction. One etiological mechanism implicated in the pathophysiology of the aforementioned psychiatric disorders is cellular stress and consequent adaptive responses in the endoplasmic reticulum (ER) that can result from a variety of environmental and physical factors. The ER is an organelle that serves essential roles in protein modification, folding, and maturation of proteins; however, the specific role of ER stress in altered social behavior is unknown. In this study, treatment with tunicamycin, an ER stress inducer, enhanced the phosphorylation level of inositol-requiring ER-to-nucleus signal kinase 1 (IRE1) and increased X-box-binding protein 1 (XBP1) mRNA splicing activity in the mouse PFC, whereas inhibition of IRE1/XBP1 pathway in PFC by a viral particle approach attenuated social behavioral deficits caused by tunicamycin treatment. Reduced estrogen receptor beta (ERβ) protein levels were found in the PFC of male mice following tunicamycin treatment. Pretreatment with an ERβ specific agonist, ERB-041 significantly attenuated tunicamycin-induced deficits in social behavior, and activation of IRE1/XBP1 pathway in mouse PFC. Moreover, ERB-041 inhibited tunicamycin-induced increases in functional connectivity between PFC and hippocampus in male mice. Together, these results show that ERβ agonist attenuates ER stress-induced deficits in social behavior through the IRE-1/XBP1 pathway.
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Affiliation(s)
- Amanda Crider
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, 997 St. Sebastian Way, Augusta, GA, 30912, USA
| | - Tyler Nelson
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, 997 St. Sebastian Way, Augusta, GA, 30912, USA
| | - Talisha Davis
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, 997 St. Sebastian Way, Augusta, GA, 30912, USA
| | - Kiley Fagan
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, 997 St. Sebastian Way, Augusta, GA, 30912, USA
| | - Kumar Vaibhav
- Department of Neurosurgery, and Department of Medical Laboratory Imaging and Radiologic Sciences (MLLIRS-CAHS), Augusta University, Augusta, GA, 30912, USA
| | - Matthew Luo
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, 997 St. Sebastian Way, Augusta, GA, 30912, USA
| | - Sunay Kamalasanan
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, 997 St. Sebastian Way, Augusta, GA, 30912, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, USA
| | - Anilkumar Pillai
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, 997 St. Sebastian Way, Augusta, GA, 30912, USA.
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Naughton SX, Terry AV. Neurotoxicity in acute and repeated organophosphate exposure. Toxicology 2018; 408:101-112. [PMID: 30144465 DOI: 10.1016/j.tox.2018.08.011] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 08/03/2018] [Accepted: 08/21/2018] [Indexed: 01/28/2023]
Abstract
The term organophosphate (OP) refers to a diverse group of chemicals that are found in hundreds of products worldwide. As pesticides, their most common use, OPs are clearly beneficial for agricultural productivity and the control of deadly vector-borne illnesses. However, as a consequence of their widespread use, OPs are now among the most common synthetic chemicals detected in the environment as well as in animal and human tissues. This is an increasing environmental concern because many OPs are highly toxic and both accidental and intentional exposures to OPs resulting in deleterious health effects have been documented for decades. Some of these deleterious health effects include a variety of long-term neurological and psychiatric disturbances including impairments in attention, memory, and other domains of cognition. Moreover, some chronic illnesses that manifest these symptoms such as Gulf War Illness and Aerotoxic Syndrome have (at least in part) been attributed to OP exposure. In addition to acute acetylcholinesterase inhibition, OPs may affect a number of additional targets that lead to oxidative stress, axonal transport deficits, neuroinflammation, and autoimmunity. Some of these targets could be exploited for therapeutic purposes. The purpose of this review is thus to: 1) describe the important uses of organophosphate (OP)-based compounds worldwide, 2) provide an overview of the various risks and toxicology associated with OP exposure, particularly long-term neurologic and psychiatric symptoms, 3) discuss mechanisms of OP toxicity beyond cholinesterase inhibition, 4) review potential therapeutic strategies to reverse the acute toxicity and long term deleterious effects of OPs.
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Affiliation(s)
- Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia.
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26
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Naughton SX, Hernandez CM, Beck WD, Poddar I, Yanasak N, Lin PC, Terry AV. Repeated exposures to diisopropylfluorophosphate result in structural disruptions of myelinated axons and persistent impairments of axonal transport in the brains of rats. Toxicology 2018; 406-407:92-103. [DOI: 10.1016/j.tox.2018.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/02/2018] [Accepted: 06/08/2018] [Indexed: 01/17/2023]
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Liu R, Crawford J, Callahan PM, Terry AV, Constantinidis C, Blake DT. Intermittent stimulation in the nucleus basalis of meynert improves sustained attention in rhesus monkeys. Neuropharmacology 2018; 137:202-210. [PMID: 29704983 DOI: 10.1016/j.neuropharm.2018.04.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/30/2018] [Accepted: 04/23/2018] [Indexed: 01/29/2023]
Abstract
Sustained attention is essential in important behaviors in daily life. Many neuropsychiatric disorders are characterized by a compromised ability to sustain attention, making this cognitive domain an important therapeutic target. In this study, we tested a novel method of improving sustained attention. Monkeys were engaged in a continuous performance task (CPT) while the nucleus basalis of Meynert (NB), the main source of cholinergic innervation of the neocortex, was stimulated. Intermittent NB stimulation improved the animals' performance by increasing the hit rate and decreasing the false alarm rate. Administration of the cholinesterase inhibitor donepezil or the muscarinic antagonist scopolamine alone impaired performance, whereas the nicotinic antagonist mecamylamine alone improved performance. Applying NB stimulation while mecamylamine or donepezil were administered impaired CPT performance. Methylphenidate, a monoaminergic psychostimulant, was applied in conjunction with intermittent stimulation as a negative control, as it does not directly modulate cholinergic output. Methylphenidate also improved performance, and it produced further improvement when combined with NB stimulation. The additive effect of the combination suggested NB stimulation altered behavior independently from methylphenidate effects. We conclude that basal forebrain projections contribute to sustained attention, and that intermittent NB stimulation is an effective way of improving performance.
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Affiliation(s)
- Ruifeng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510060, China; Brain and Behavior Discovery Institute, Department of Neurology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Jonathan Crawford
- Brain and Behavior Discovery Institute, Department of Neurology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Christos Constantinidis
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - David T Blake
- Brain and Behavior Discovery Institute, Department of Neurology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA.
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Yang X, Naughton SX, Han Z, He M, Zheng YG, Terry AV, Bartlett MG. Mass Spectrometric Quantitation of Tubulin Acetylation from Pepsin-Digested Rat Brain Tissue Using a Novel Stable-Isotope Standard and Capture by Anti-Peptide Antibody (SISCAPA) Method. Anal Chem 2018; 90:2155-2163. [PMID: 29320166 DOI: 10.1021/acs.analchem.7b04484] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Acetylation of α-tubulin at Lys-40 is a potential biomarker for cognitive deficits in various neurological disorders. However, this key post-translational modification (PTM) has not been previously studied with mass spectrometry, due to the inadequate distribution of tryptic cleavage sites. Following peptic digestion, a surrogate sequence containing this key PTM site was identified and was found to be stable and quantitatively reproducible. A highly sensitive and specific SISCAPA-LC-MS method for quantitating rat brain tubulin acetylation was developed, validated, and applied, and only required a small amount of tissue (2.2 mg). This workflow includes peptic digestion, stable-isotope dilution, capture with antiacetylated peptide antibody bound on protein G beads, and quantitation using LC-MS. The method allowed a lower limit of quantitation at 2.50 pmol/mg and provided a linear range of 2.50-62.50 pmol/mg. Selectivity, intra and interday precision and accuracy were also validated. This method has been successfully applied in a preclinical study of organophosphate neurotoxicity, and we found that chronic exposure to chlorpyrifos led to a significant and persistent inhibition of brain tubulin acetylation.
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Affiliation(s)
- Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy , 250 W. Green Street, Athens, Georgia 30602, United States
| | - Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University , Augusta, Georgia 30912, United States
| | - Zhen Han
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy , 250 W. Green Street, Athens, Georgia 30602, United States
| | - Maomao He
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy , 250 W. Green Street, Athens, Georgia 30602, United States
| | - Y George Zheng
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy , 250 W. Green Street, Athens, Georgia 30602, United States
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University , Augusta, Georgia 30912, United States
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy , 250 W. Green Street, Athens, Georgia 30602, United States
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Abstract
Nearly 30 years of experimental evidence supports the argument that ligands of nicotinic acetylcholine receptors (nAChRs) have potential as therapeutic agents. However, as in the famous Lewis Carroll novel "Alice in Wonderland", there have been many unexpected adventures along the pathway of development, and few nAChR ligands have been approved for any clinical condition to date with the exception of nicotine dependence. The recent failures of nAChR ligands in AD and schizophrenia clinical trials have reduced enthusiasm for this therapeutic strategy and many pharmaceutical companies have now abandoned this field of research. As with other clinical failures, multiple questions arise as to the basis for the failure. More generic questions focus on a potential translational gap between the animal models used and the human clinical condition they are meant to simulate, or the clinical trial mindset that large Ns have to be achieved for statistical power (often requiring multiple trial sites) as opposed to smaller patient cohorts at limited sites where conditions can be better controlled and replicated. More specific to the nAChR field are questions about subtype selectivity, dose selection, whether an agonist, antagonist, or allosteric modulator strategy is best, etc. The purpose of this review is to discuss each of these questions, but also to provide a brief overview of the remarkable progress that has been made over the last three decades in our understanding of this unique ligand-gated ion channel and how this new knowledge may help us improve drug development successes in the future.
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Affiliation(s)
- Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222 Vésenaz, Geneva, Switzerland.
| | - A V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta 30912, Georgia
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30
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Blake DT, Terry AV, Plagenhoef M, Constantinidis C, Liu R. Potential for intermittent stimulation of nucleus basalis of Meynert to impact treatment of alzheimer's disease. Commun Integr Biol 2017; 10:e1389359. [PMID: 29260798 PMCID: PMC5731511 DOI: 10.1080/19420889.2017.1389359] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/03/2017] [Indexed: 10/25/2022] Open
Abstract
The brain's cholinergic arousal pathways decline in parallel with the brain's executive functions in aging and Alzheimer's Disease. The frontline and currently most effective approach to treating Alzheimer's disease is the administration of cholinesterase inhibitors, which, in a dose dependent manner, improve the symptoms of cognitive decline over the first months of treatment before further decline occurs. We recently showed that intermittent deep brain stimulation of the nucleus basalis of Meynert improves working memory function in young adult monkeys, and that this improvement depended on cholinergic function. Within minutes, the monkeys' ability to remember stimuli over a delay period improved. Over months, the monkeys performed the working memory task better even in the absence of stimulation. Here, we show historical data from our monkey colony in which more than two dozen animals have performed the same behavioral task to asymptotic performance levels. Using a distribution based on our historical data, we estimate that the monkeys receiving intermittent stimulation leapt over the performance level of 32-44 percent of peer animals in the first several months after stimulation was initiated. Implications for a parallel increase in cognitive function for early Alzheimer's patients are discussed.
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Affiliation(s)
- David T Blake
- Brain and Behavior Discovery Institute, Department of Neurology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Marc Plagenhoef
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Christos Constantinidis
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Ruifeng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
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Poddar I, Callahan PM, Hernandez CM, Yang X, Bartlett MG, Terry AV. Tropisetron enhances recognition memory in rats chronically treated with risperidone or quetiapine. Biochem Pharmacol 2017; 151:180-187. [PMID: 29175423 DOI: 10.1016/j.bcp.2017.11.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 11/22/2017] [Indexed: 12/16/2022]
Abstract
While impairments of cognition in schizophrenia have the greatest impact on long-term functional outcome, the currently prescribed treatments, antipsychotic drugs (APDs), do not effectively improve cognition. Moreover, while more than 20 years have been devoted to the development of new drugs to treat cognitive deficits in schizophrenia, none have been approved to date. One area that has not been given proper attention at the preclinical or clinical stage of drug development is the chronic medication history of the test subject. Hence, very little is known about how chronic treatment with drugs that affect multiple receptors like APDs influence the response to a potential pro-cognitive agent. Therefore, the purpose of this study was to evaluate the α7 nicotinic acetylcholine receptor (α7 nAChR) partial agonist, tropisetron in rats chronically treated with APDs with distinct pharmacological profiles. Rats were treated orally with either risperidone (2.5 mg/kg/day) or quetiapine (25.0 mg/kg/day) for 30 or 90 days and then an acute injection of vehicle or tropisetron (3.0 mg/kg) was administered before training in a novel object recognition (NOR) task. After a 48 h delay (when recollection of the familiar object was impaired in vehicle-treated animals) neither 30 nor 90 days of risperidone or quetiapine treatment improved NOR performance. In contrast, tropisetron markedly improved NOR performance in rats treated with either APD for 30 or 90 days. These animal data reinforce the argument that two commonly prescribed APDs are not pro-cognitive agents and that α7 nAChR ligands like tropisetron have potential as adjunctive treatments in schizophrenia.
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Affiliation(s)
- Indrani Poddar
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, Georgia
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, Georgia; Small Animal Behavior Core, Augusta University, Augusta, GA 30912, Georgia
| | - Caterina M Hernandez
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, Georgia; Small Animal Behavior Core, Augusta University, Augusta, GA 30912, Georgia
| | - Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA 30607, Georgia
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA 30607, Georgia
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, Georgia; Small Animal Behavior Core, Augusta University, Augusta, GA 30912, Georgia.
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Liu R, Crawford J, Callahan PM, Terry AV, Constantinidis C, Blake DT. Intermittent Stimulation of the Nucleus Basalis of Meynert Improves Working Memory in Adult Monkeys. Curr Biol 2017; 27:2640-2646.e4. [PMID: 28823679 PMCID: PMC5759307 DOI: 10.1016/j.cub.2017.07.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/07/2017] [Accepted: 07/11/2017] [Indexed: 10/19/2022]
Abstract
Acetylcholine in the neocortex is critical for executive function [1-3]. Degeneration of cholinergic neurons in aging and Alzheimer's dementia is commonly treated with cholinesterase inhibitors [4-7]; however, these are modestly effective and are associated with side effects that preclude effective dosing in many patients [8]. Electrical activation of the nucleus basalis (NB) of Meynert, the source of neocortical acetylcholine [9, 10], provides a potential method of improving cholinergic activation [11, 12]. Here we tested whether NB stimulation would improve performance of a working memory task in a nonhuman primate model. Unexpectedly, intermittent stimulation proved to be most beneficial (60 pulses per second, for 20 s every minute), whereas continuous stimulation often impaired performance. Pharmacological experiments confirmed that the effects depended on cholinergic activation. Donepezil, a cholinesterase inhibitor, restored performance in animals impaired by continuous stimulation but did not improve performance further during intermittent stimulation. Intermittent stimulation was rendered ineffective by either nicotinic or muscarinic receptor antagonists. In the months after stimulation began, performance also improved in sessions without stimulation. Our results reveal that intermittent NB stimulation can improve working memory, a finding that has implications for restoring cognitive function in aging and Alzheimer's dementia.
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Affiliation(s)
- Ruifeng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China; Brain and Behavior Discovery Institute, Department of Neurology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Jonathan Crawford
- Brain and Behavior Discovery Institute, Department of Neurology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Christos Constantinidis
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - David T Blake
- Brain and Behavior Discovery Institute, Department of Neurology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA.
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Gao J, Naughton SX, Beck WD, Hernandez CM, Wu G, Wei Z, Yang X, Bartlett MG, Terry AV. Chlorpyrifos and chlorpyrifos oxon impair the transport of membrane bound organelles in rat cortical axons. Neurotoxicology 2017; 62:111-123. [PMID: 28600141 DOI: 10.1016/j.neuro.2017.06.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 06/02/2017] [Accepted: 06/02/2017] [Indexed: 01/13/2023]
Abstract
Chlorpyrifos (CPF) is an extensively used organophosphorus pesticide that has recently come under increasing scrutiny due to environmental health concerns particularly its association with neurodevelopmental defects. While the insecticidal actions and acute toxicity of CPF are attributed to its oxon metabolite (CPO) which potently inhibits the cholinergic enzyme acetylcholinesterase (AChE), there is significant evidence that CPF, CPO, and other organophosphates may affect a variety of neuronal targets and processes that are not directly related to AChE. Previously, in adult rat sciatic nerves ex vivo and postnatal neurons from rats in vitro we observed that CPF and CPO impaired the movements of vesicles and mitochondria in axons. Here, in embryonic neurons from rats in culture, we evaluated 24h exposures to CPF and CPO across picomolar to micromolar concentrations for effects on fast axonal transport of membrane bound organelles (MBOs) that contained the amyloid precursor protein (APP) tagged with the fluorescent marker, Dendra2 (APPDendra2). The most notable observations of this study were concentration-dependent decreases in the velocity and percentage of MBOs moving in the anterograde direction, an increase in the number of stationary MBOs, and an increased frequency of pauses associated with both CPF and CPO. These effects occurred at concentrations that did not significantly inhibit AChE activity, they were not blocked by cholinergic receptor antagonists, and they were not associated with compromised cell viability. These effects of CPF and CPO may be significant given the importance of axonal transport to neuronal development as well the function of fully developed neurons.
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Affiliation(s)
- Jie Gao
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Caterina M Hernandez
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia
| | - Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, 250 W. Green Street, Athens, 30602, Georgia
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, 250 W. Green Street, Athens, 30602, Georgia
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, 30912, Georgia.
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Pandya CD, Hoda N, Crider A, Peter D, Kutiyanawalla A, Kumar S, Ahmed AO, Turecki G, Hernandez CM, Terry AV, Pillai A. Transglutaminase 2 overexpression induces depressive-like behavior and impaired TrkB signaling in mice. Mol Psychiatry 2017; 22:745-753. [PMID: 27620841 PMCID: PMC5348279 DOI: 10.1038/mp.2016.145] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 06/27/2016] [Accepted: 07/20/2016] [Indexed: 01/15/2023]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) and brain-derived neurotrophic factor (BDNF) are two signaling molecules that have important regulatory roles in the development and plasticity of neural circuits that are known to be altered in depression. However, the mechanism by which 5-HT regulates BDNF signaling is unknown. In the present study, we found that 5-HT treatment increases BDNF receptor, TrkB (tropomyosin related kinase B), levels in mouse primary cortical neurons via a Rac1 (RAS-related C3 botulinum toxin substrate 1)-dependent mechanism. Significant increases in the levels of type-2 transglutaminase (TG2, which is implicated in transamidation of 5-HT to Rac1) are observed in the mouse prefrontal cortex (PFC) following chronic exposure to stress. We also found that TG2 levels are increased in the post-mortem PFC of depressed suicide subjects relative to matched controls. Moreover, in mice, neuronal overexpression of TG2 resulted in the atrophy of neurons and reduced levels of TrkB in the PFC as well as a depressive-like phenotype. Overexpression of TG2 in mouse cortical neurons reduced TrkB levels as a result of impaired endocytosis of TrkB. TG2 inhibition by either a viral particle or pharmacological approach attenuated behavioral deficits caused by chronic unpredictable stress. Moreover, the overexpression of TrkB in the mouse PFC ameliorated the depressive-like phenotype of TG2-overexpressed mice. Taken together, these post-mortem and preclinical findings identify TG2 as a critical mediator of the altered TrkB expression and depressive-like behaviors associated with chronic exposure to stress and suggest that TG2 may represent a novel therapeutic target in depression.
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Affiliation(s)
- Chirayu D Pandya
- Department of Psychiatry and Health Behavior, Augusta University, Augusta, Georgia, USA
| | - Nasrul Hoda
- Department of Medical Laboratory, Imaging and Radiologic Sciences, Augusta University, Augusta, Georgia, USA
| | - Amanda Crider
- Department of Psychiatry and Health Behavior, Augusta University, Augusta, Georgia, USA
| | - Diya Peter
- Department of Psychiatry and Health Behavior, Augusta University, Augusta, Georgia, USA
| | - Ammar Kutiyanawalla
- Department of Psychiatry and Health Behavior, Augusta University, Augusta, Georgia, USA
| | - Sanjiv Kumar
- Vascular Biology Center, Augusta University, Augusta, Georgia, USA
| | - Anthony O Ahmed
- Department of Psychiatry, Weill Cornell Medical College, White Plains, NY, USA
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Depressive Disorders Program, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Caterina M Hernandez
- Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA
| | - Anilkumar Pillai
- Department of Psychiatry and Health Behavior, Augusta University, Augusta, Georgia, USA
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35
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Callahan PM, Bertrand D, Bertrand S, Plagenhoef MR, Terry AV. Tropisetron sensitizes α7 containing nicotinic receptors to low levels of acetylcholine in vitro and improves memory-related task performance in young and aged animals. Neuropharmacology 2017; 117:422-433. [PMID: 28259598 DOI: 10.1016/j.neuropharm.2017.02.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/06/2017] [Accepted: 02/25/2017] [Indexed: 01/02/2023]
Abstract
Tropisetron, a 5-HT3 receptor antagonist commonly prescribed for chemotherapy-induced nausea and vomiting also exhibits high affinity, partial agonist activity at α7 nicotinic acetylcholine receptors (α7 nAChRs). α7 nAChRs are considered viable therapeutic targets for neuropsychiatric disorders such as Alzheimer's disease (AD). Here we further explored the nAChR pharmacology of tropisetron to include the homomeric α7 nAChR and recently characterized heteromeric α7β2 nAChR (1:10 ratio) and we evaluated its cognitive effects in young and aged animals. Electrophysiological studies on human nAChRs expressed in Xenopus oocytes confirmed the partial agonist activity of tropisetron at α7 nAChRs (EC50 ∼2.4 μM) with a similar effect at α7β2 nAChRs (EC50 ∼1.5 μM). Moreover, currents evoked by irregular pulses of acetylcholine (40 μM) at α7 and α7β2 nAChRs were enhanced during sustained exposure to low concentrations of tropisetron (10 and 30 nM) indicative of a "priming" or co-agonist effect. Tropisetron (0.1-10 mg/kg) improved novel object recognition performance in young Sprague-Dawley rats and in aged Fischer rats. In aged male and female rhesus monkeys, tropisetron (0.03-1 mg/kg) produced a 17% increase from baseline levels in delayed match to sample long delay accuracy while combination of non-effective doses of donepezil (0.1 mg/kg) and tropisetron (0.03 and 0.1 mg/kg) produced a 24% change in accuracy. Collectively, these animal experiments indicate that tropisetron enhances cognition and has the ability to improve the effective dose range of currently prescribed AD therapy (donepezil). Moreover, these effects may be explained by tropisetron's ability to sensitize α7 containing nAChRs to low levels of acetylcholine.
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Affiliation(s)
- Patrick M Callahan
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA 30912, United States.
| | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222 Vésenaz, Geneva, Switzerland
| | - Sonia Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222 Vésenaz, Geneva, Switzerland
| | - Marc R Plagenhoef
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA 30912, United States
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA 30912, United States
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Gao J, Midde N, Zhu J, Terry AV, McInnes C, Chapman JM. Synthesis and biological evaluation of ranitidine analogs as multiple-target-directed cognitive enhancers for the treatment of Alzheimer's disease. Bioorg Med Chem Lett 2016; 26:5573-5579. [PMID: 27769620 PMCID: PMC5185470 DOI: 10.1016/j.bmcl.2016.09.072] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/02/2016] [Accepted: 09/28/2016] [Indexed: 11/17/2022]
Abstract
Using molecular modeling and rationally designed structural modifications, the multi-target structure-activity relationship for a series of ranitidine analogs has been investigated. Incorporation of a variety of isosteric groups indicated that appropriate aromatic moieties provide optimal interactions with the hydrophobic and π-π interactions with the peripheral anionic site of the AChE active site. The SAR of a series of cyclic imides demonstrated that AChE inhibition is increased by additional aromatic rings, where 1,8-naphthalimide derivatives were the most potent analogs and other key determinants were revealed. In addition to improving AChE activity and chemical stability, structural modifications allowed determination of binding affinities and selectivities for M1-M4 receptors and butyrylcholinesterase (BuChE). These results as a whole indicate that the 4-nitropyridazine moiety of the JWS-USC-75IX parent ranitidine compound (JWS) can be replaced with other chemotypes while retaining effective AChE inhibition. These studies allowed investigation into multitargeted binding to key receptors and warrant further investigation into 1,8-naphthalimide ranitidine derivatives for the treatment of Alzheimer's disease.
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Affiliation(s)
- Jie Gao
- Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA; Department of Pharmacology and Toxicology, Augusta University, Health Sciences Campus, CB-3530, 1459 Laney Walker Blvd., Augusta, GA 30912, USA
| | - Narasimha Midde
- Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA
| | - Jun Zhu
- Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Augusta University, Health Sciences Campus, CB-3530, 1459 Laney Walker Blvd., Augusta, GA 30912, USA
| | - Campbell McInnes
- Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA.
| | - James M Chapman
- Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA
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Terry AV, Plagenhoef M, Callahan PM. Effects of the nicotinic agonist varenicline on the performance of tasks of cognition in aged and middle-aged rhesus and pigtail monkeys. Psychopharmacology (Berl) 2016; 233:761-71. [PMID: 26612616 PMCID: PMC4752862 DOI: 10.1007/s00213-015-4154-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/10/2015] [Indexed: 10/22/2022]
Abstract
RATIONALE Due to the rising costs of drug development especially in the field of neuropsychiatry, there is increasing interest in efforts to identify new clinical uses for existing approved drugs (i.e., drug repurposing). OBJECTIVES The purpose of this work was to evaluate in animals the smoking cessation agent, varenicline, a partial agonist at α4β2 and full agonist at α7 nicotinic acetylcholine receptors, for its potential as a repurposed drug for disorders of cognition. METHODS Oral doses of varenicline ranging from 0.01 to 0.3 mg/kg were evaluated in aged and middle-aged monkeys for effects on the following: working/short-term memory in a delayed match to sample (DMTS) task, distractibility in a distractor version of the DMTS (DMTS-D), and cognitive flexibility in a ketamine-impaired reversal learning task. RESULTS In dose-effect studies in the DMTS and DMTS-D tasks, varenicline was not associated with statistically significant effects on performance. However, individualized "optimal doses" were effective when repeated on a separate occasion (i.e., improving DMTS accuracy at long delays and DMTS-D accuracy at short delays by approximately 13.6 and 19.6 percentage points above baseline, respectively). In reversal learning studies, ketamine impaired accuracy and increased perseverative responding, effects that were attenuated by all three doses of varenicline that were evaluated. CONCLUSIONS While the effects of varenicline across the different behavioral tasks were modest, these data suggest that varenicline may have potential as a repurposed drug for disorders of cognition associated with aging (e.g., Alzheimer's disease), as well as those not necessarily associated with advanced age (e.g., schizophrenia).
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Gao J, Naughton SX, Wulff H, Singh V, Beck WD, Magrane J, Thomas B, Kaidery NA, Hernandez CM, Terry AV. Diisopropylfluorophosphate Impairs the Transport of Membrane-Bound Organelles in Rat Cortical Axons. J Pharmacol Exp Ther 2015; 356:645-55. [PMID: 26718240 DOI: 10.1124/jpet.115.230839] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 12/29/2015] [Indexed: 12/27/2022] Open
Abstract
The extensive use of organophosphates (OPs) is an ongoing environmental health concern due to multiple reports of OP-related neurologic abnormalities. The mechanism of the acute toxicity of OPs has been attributed to inhibition of acetylcholinesterase (AChE), but there is growing evidence that this may not account for all the long-term neurotoxic effects of OPs. In previous experiments (using ex vivo and in vitro model systems) we observed that the insecticide OP chlorpyrifos impaired the movements of vesicles and mitochondria in axons. Here, using a time-lapse imaging technique, we evaluated the OP-nerve agent diisopropylfluorophosphate (DFP) across a wide range of concentrations (subnanomolar to micromolar) for effects on fast axonal transport of membrane-bound organelles (MBOs) that contain the amyloid precursor protein (APP) tagged with the fluorescent marker Dendra2 (APPDendra2). Both 1 and 24 hours of exposure to DFP and a positive control compound, colchicine, resulted in a decrease in the velocity of anterograde and retrograde movements of MBOs and an increase in the number of stationary MBOs. These effects occurred at picomolar (100 pM) to low nanomolar (0.1 nM) concentrations that were not associated with compromised cell viability or cytoskeletal damage. Moreover, the effects of DFP on axonal transport occurred at concentrations that did not inhibit AChE activity, and they were not blocked by cholinergic receptor antagonists. Given the fundamental importance of axonal transport to neuronal function, these observations may explain some of the long-term neurologic deficits that have been observed in humans who have been exposed to OPs.
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Affiliation(s)
- Jie Gao
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Sean X Naughton
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Heike Wulff
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Vikrant Singh
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Jordi Magrane
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Bobby Thomas
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Navneet Ammal Kaidery
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Caterina M Hernandez
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia (J.G., V.S., S.X.N., W.D.B., B.T., N.A.K., C.M.H., A.V.T.); Department of Pharmacology, University of California-Davis, Davis, California (H.W.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York (J.M.)
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Koelsch G, Detke MJ, Stevens KE, Meltzer LT, Terry AV, Callahan PM, Yoshimura RF, Bilcer G, Anderson PC, Ng J, Ng R, Kelly TA. APN1125: A clinical stage α7 nicotinic acetylcholine receptor partial agonist. Biochem Pharmacol 2015. [DOI: 10.1016/j.bcp.2015.08.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Yang X, Poddar I, Hernandez CM, Terry AV, Bartlett MG. Simultaneous quantitation of quetiapine and its active metabolite norquetiapine in rat plasma and brain tissue by high performance liquid chromatography/electrospray ionization tandem mass spectrometry (LC-MS/MS). J Chromatogr B Analyt Technol Biomed Life Sci 2015; 1002:71-7. [PMID: 26313131 DOI: 10.1016/j.jchromb.2015.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/31/2015] [Accepted: 08/07/2015] [Indexed: 01/29/2023]
Abstract
A sensitive method to simultaneously quantitate quetiapine and norquetiapine in rat plasma and brain tissue was developed using a one-step liquid-liquid extraction for sample preparation and LC-MS/MS for detection. The method provided a linear range of 1.0-500.0ng/mL for each analyte in plasma and 3.0-1500.0ng/g in brain tissue. The method was validated with precision within 15% relative standard deviation (RSD), accuracy within 15% relative error (RE), matrix effects within 10% and a consistent recovery. This method has been successfully applied in a preclinical study of quetiapine and norquetiapine to simultaneously determine their concentrations in rat plasma and brain tissue.
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Affiliation(s)
- Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602-2352, United States
| | - Indrani Poddar
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Caterina M Hernandez
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602-2352, United States.
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Li P, Li Z, Beck WD, Callahan PM, Terry AV, Bar-Peled M, Bartlett MG. Bio-generation of stable isotope-labeled internal standards for absolute and relative quantitation of phase II drug metabolites in plasma samples using LC–MS/MS. Anal Bioanal Chem 2015; 407:4053-63. [DOI: 10.1007/s00216-015-8614-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/20/2015] [Accepted: 03/03/2015] [Indexed: 01/24/2023]
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Hernandez CM, Beck WD, Naughton SX, Poddar I, Adam BL, Yanasak N, Middleton C, Terry AV. Repeated exposure to chlorpyrifos leads to prolonged impairments of axonal transport in the living rodent brain. Neurotoxicology 2015; 47:17-26. [PMID: 25614231 DOI: 10.1016/j.neuro.2015.01.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/06/2015] [Accepted: 01/11/2015] [Indexed: 01/07/2023]
Abstract
The toxicity of the class of chemicals known as the organophosphates (OP) is most commonly attributed to the inhibition of the enzyme acetylcholinesterase. However, there is significant evidence that this mechanism may not account for all of the deleterious neurologic and neurobehavioral symptoms of OP exposure, especially those associated with levels that produce no overt signs of acute toxicity. In the study described here we evaluated the effects of the commonly used OP-pesticide, chlorpyrifos (CPF) on axonal transport in the brains of living rats using manganese (Mn(2+))-enhanced magnetic resonance imaging (MEMRI) of the optic nerve (ON) projections from the retina to the superior colliculus (SC). T1-weighted MEMRI scans were evaluated at 6 and 24h after intravitreal injection of Mn(2+). As a positive control for axonal transport deficits, initial studies were conducted with the tropolone alkaloid colchicine administered by intravitreal injection. In subsequent studies both single and repeated exposures to CPF were evaluated for effects on axonal transport using MEMRI. As expected, intravitreal injection of colchicine (2.5μg) produced a robust decrease in transport of Mn(2+) along the optic nerve (ON) and to the superior colliculus (SC) (as indicated by the reduced MEMRI contrast). A single subcutaneous (s.c.) injection of CPF (18.0mg/kg) was not associated with significant alterations in the transport of Mn(2+). Conversely, 14-days of repeated s.c. exposure to CPF (18.0mg/kg/day) was associated with decreased transport of Mn(2+) along the ONs and to the SC, an effect that was also present after a 30-day (CPF-free) washout period. These results indicate that repeated exposures to a commonly used pesticide, CPF can result in persistent alterations in axonal transport in the living mammalian brain. Given the fundamental importance of axonal transport to neuronal function, these observations may (at least in part) explain some of the long term neurological deficits that have been observed in humans who have been repeatedly exposed to doses of OPs not associated with acute toxicity.
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Affiliation(s)
- Caterina M Hernandez
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Sean X Naughton
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Indrani Poddar
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Bao-Ling Adam
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Nathan Yanasak
- Core Imaging Facility for Small Animals (CIFSA), Georgia Regents University, Augusta, GA 30912, United States
| | - Chris Middleton
- Core Imaging Facility for Small Animals (CIFSA), Georgia Regents University, Augusta, GA 30912, United States
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States.
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Abstract
The ability to focus one's attention on important environmental stimuli while ignoring irrelevant stimuli is fundamental to human cognition and intellectual function. Attention is inextricably linked to perception, learning and memory, and executive function; however, it is often impaired in a variety of neuropsychiatric disorders, including Alzheimer's disease, schizophrenia, depression, and attention deficit hyperactivity disorder (ADHD). Accordingly, attention is considered as an important therapeutic target in these disorders. The purpose of this chapter is to provide an overview of the most common behavioral paradigms of attention that have been used in animals (particularly rodents) and to review the literature where these tasks have been employed to elucidate neurobiological substrates of attention as well as to evaluate novel pharmacological agents for their potential as treatments for disorders of attention. These paradigms include two tasks of sustained attention that were developed as rodent analogues of the human Continuous Performance Task (CPT), the Five-Choice Serial Reaction Time Task (5-CSRTT) and the more recently introduced Five-Choice Continuous Performance Task (5C-CPT), and the Signal Detection Task (SDT) which was designed to emphasize temporal components of attention.
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Affiliation(s)
- Patrick M Callahan
- Department of Pharmacology and Toxicology, CB-3545, Georgia Regents University, 1120 Fifteenth Street, Augusta, GA, 30912-2450, USA
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Li P, Beck WD, Callahan PM, Terry AV, Bartlett MG. Pharmacokinetics of cotinine in rats: a potential therapeutic agent for disorders of cognitive function. Pharmacol Rep 2014; 67:494-500. [PMID: 25933960 DOI: 10.1016/j.pharep.2014.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/24/2014] [Accepted: 12/05/2014] [Indexed: 02/09/2023]
Abstract
BACKGROUND Attention has been paid to cotinine (COT), one of the major metabolites of nicotine (NIC), for its pro-cognitive effects and potential therapeutic activities against Alzheimer's disease (AD) and other types of cognitive impairment. In order to facilitate pharmacological and toxicological studies on COT for its pro-cognitive activities, we conducted a pharmacokinetic (PK) study of COT in rats, providing important oral and intravenously (iv) PK information. METHODS In this study, plasma samples were obtained up to 48 h after COT was dosed to rats orally and iv at a dose of 3mg/kg. Plasma samples were prepared and analyzed using a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) bioanalytical method, providing concentration profiles of COT and metabolites after oral and iv administrations. RESULTS The data were fitted into a one-compartment model and a two-compartment model for the oral and iv groups, respectively, providing important PK information for COT including PK profiles, half-life, clearance and bioavailability. The results suggested fast absorption, slow elimination and high bioavailability of COT in rats. CONCLUSIONS Several important facts about the PK properties in rats suggested COT could be a potential pro-cognitive agent. Information about the pharmacokinetics of COT in rats revealed in this study is of great importance for the future studies on COT or potential COT analogs as agents for improving cognition.
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Affiliation(s)
- Pei Li
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, USA
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, USA
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, USA; Small Animal Behavior Core, Georgia Regents University, Augusta, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, USA; Small Animal Behavior Core, Georgia Regents University, Augusta, USA
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, USA.
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Abstract
The nicotine metabolite cotinine (1-methyl-5-[3-pyridynl]-2-pyrrolidinone), like its precursor, has been found to exhibit procognitive and neuroprotective effects in some model systems; however, the mechanism of these effects is unknown. In this study, both the R-(+) and S-(-) isomers of cotinine were initially evaluated in an extensive profiling screen and found to be relatively inactive across a wide range of potential pharmacologic targets. Electrophysiological studies on human α4β2 and α7 nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes confirmed the absence of agonistic activity of cotinine at α4β2 or α7 nAChRs. However, a significant increase in the current evoked by a low concentration of acetylcholine was observed at α7 nAChRs exposed to 1.0 μM R-(+)- or S-(-)-cotinine. Based on these results, we used a spontaneous novel object recognition (NOR) procedure for rodents to test the hypothesis that R-(+)- or S-(-)-cotinine might improve recognition memory when administered alone or in combination with the Alzheimer's disease (AD) therapeutic agent donepezil. Although both isomers enhanced NOR performance when they were coadministered with donepezil, neither isomer was active alone. Moreover, the procognitive effects of the drug combinations were blocked by methyllycaconitine and dihydro-β-erythroidine, indicating that both α7 and α4β2 nAChRs contribute to the response. These results indicate that cotinine may sensitize α7 nAChRs to low levels of acetylcholine (a previously uncharacterized mechanism), and that cotinine could be used as an adjunctive agent to improve the effective dose range of cholinergic compounds (e.g., donepezil) in the treatment of AD and other memory disorders.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, and Small Animal Behavior Core, Georgia Regents University, Augusta, Georgia (A.V.T., P.M.C.); and HiQScreen Sàrl, Geneva, Switzerland (D.B.)
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, and Small Animal Behavior Core, Georgia Regents University, Augusta, Georgia (A.V.T., P.M.C.); and HiQScreen Sàrl, Geneva, Switzerland (D.B.)
| | - Daniel Bertrand
- Department of Pharmacology and Toxicology, and Small Animal Behavior Core, Georgia Regents University, Augusta, Georgia (A.V.T., P.M.C.); and HiQScreen Sàrl, Geneva, Switzerland (D.B.)
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Terry AV, Callahan PM, Schade R, Kille NJ, Plagenhoef M. Alpha 2A adrenergic receptor agonist, guanfacine, attenuates cocaine-related impairments of inhibitory response control and working memory in animal models. Pharmacol Biochem Behav 2014; 126:63-72. [PMID: 25242808 DOI: 10.1016/j.pbb.2014.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/09/2014] [Accepted: 09/13/2014] [Indexed: 10/24/2022]
Abstract
There is considerable evidence that centrally acting α2A adrenergic receptor agonists can attenuate impairments in executive function that result from dysfunction of the prefrontal cortex. Such positive effects resulted in the recent approval by the United States Food and Drug Administration (FDA) of the α2A agonists clonidine and guanfacine for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD), but also suggest that they could have beneficial effects in substance abuse disorders and other neuropsychiatric conditions. The purpose of this study was to evaluate guanfacine for its ability to attenuate behavioral alterations associated with acute cocaine exposure in rats trained to perform a task of sustained attention, the five choice serial reaction time task (5C-SRTT) and monkeys trained to perform a task of working/short term memory, the delayed match to sample (DMTS) task. In the rodent 5C-SRTT acute intraperitoneal (i.p.) administration of cocaine (3.5-15.0mg/kg) did not affect accuracy, but was associated with dose-dependent increases in premature responses and timeout responses. Guanfacine (0.1-1.0mg/kgi.p.) dose-dependently decreased premature responses and timeout responses associated with cocaine and it attenuated similar deficits in inhibitory response control observed in a variable ITI version of the 5C-SRTT. In the DMTS task in monkeys, acute intramuscular (i.m.) administration of cocaine (4.0mg/kg) was associated with impairments in accuracy at long delay intervals, an effect that was attenuated by guanfacine (0.4mg/kg). These animal studies suggest that guanfacine may have therapeutic potential for treating impairments of executive function that are associated with the abuse of cocaine.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States; Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States.
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States; Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States
| | - Rosann Schade
- Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States
| | - Nancy J Kille
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Marc Plagenhoef
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
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Callahan PM, Terry AV, Tehim A. Effects of the nicotinic α7 receptor partial agonist GTS-21 on NMDA-glutamatergic receptor related deficits in sensorimotor gating and recognition memory in rats. Psychopharmacology (Berl) 2014; 231:3695-706. [PMID: 24595504 PMCID: PMC4748388 DOI: 10.1007/s00213-014-3509-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 02/11/2014] [Indexed: 12/11/2022]
Abstract
RATIONALE Disturbances in information processing and cognitive function are key features of schizophrenia. Nicotinic α7 acetylcholine receptors (α7-nAChR) are involved in sensory gating and cognition, thereby representing a viable therapeutic strategy. OBJECTIVES AND METHODS We investigated the effects of GTS-21, an α7-nAChR partial agonist, on prepulse inhibition (PPI) of acoustic startle in two pharmacologic impairment models in Wistar male rats: NMDA-glutamate receptor antagonism by MK-801 and dopamine receptor agonism by apomorphine. The cognitive effects of GTS-21 were assessed using the object recognition task (ORT) at short (3 h) and long (48 h) delays in Sprague-Dawley male rats. Pharmacological specificity was assessed by methyllycaconitine (MLA) coadministration with GTS-21. RESULTS In the PPI task, GTS-21 (1-10 mg/kg) alone did not alter the PPI response or startle amplitude. Coadministration of GTS-21 with MK-801 (0.1 mg/kg) or apomorphine (0.5 mg/kg) abolished the pharmacologic-induced PPI impairment as did the antipsychotics clozapine (5.0 mg/kg) and haloperidol (0.3 mg/kg). MK-801 alone increased startle amplitude which was blocked by GTS-21. In the ORT, GTS-21 (0.1-10 mg/kg) reversed the MK-801 (0.08 mg/kg)-induced memory deficit at the 3 h delay and enhanced memory at the 48 h delay, an effect abolished by MLA (0.313-5 mg/kg). CONCLUSIONS The results extend our preclinical pharmacological understanding of GTS-21 to include the ability of GTS-21 to modulate NMDA-glutamate receptor function, in vivo. Given the role of NMDA-glutamate receptor involvement in schizophrenia, α7-nAChR agonists may represent a novel treatment strategy for the pathophysiological deficits of schizophrenia and other psychiatric disorders.
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Affiliation(s)
- Patrick M Callahan
- Department of Pharmacology and Toxicology, Small Animal Behavior Core, Georgia Regents University, Augusta, GA, 30912, USA,
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Terry AV, Callahan PM, Beck WD, Vandenhuerk L, Sinha S, Bouchard K, Schade R, Waller JL. Repeated exposures to diisopropylfluorophosphate result in impairments of sustained attention and persistent alterations of inhibitory response control in rats. Neurotoxicol Teratol 2014; 44:18-29. [PMID: 24819591 PMCID: PMC4099306 DOI: 10.1016/j.ntt.2014.04.069] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 04/28/2014] [Accepted: 04/30/2014] [Indexed: 11/30/2022]
Abstract
Organophosphate (OP)-based chemicals are used worldwide for many purposes and they have likely saved millions of people from starvation and disease. However, due to their toxicity they can also pose a significant environmental risk. While considerable research has focused on the acute symptoms and long-term consequences of overtly toxic exposures to OPs, less attention has been given to the subject of repeated exposures to levels that are not associated with acute symptoms (subthreshold exposures). There is clinical evidence indicating that this type of OP exposure can lead to prolonged deficits in cognition; however only a few studies have addressed this issue prospectively in animal models. In this study, repeated subthreshold exposures to the OP nerve agent diisopropylfluorophosphate (DFP) were evaluated in a 5-Choice Serial Reaction Time Task (5C-SRTT), an animal model of sustained attention. Adult rats were trained to stably perform the 5C-SRTT and then injected subcutaneously with vehicle or DFP of 0.5mg/kg every other day for 30days. Behavioral testing occurred daily during the DFP-exposure period and throughout a 45day (OP-free) washout period. Compared to vehicle-treated controls, DFP-treated rats exhibited deficits in accuracy, increases in omissions and timeout responses during the OP exposure period, while no significant effects on premature responses, perseverative responses, or response latencies were noted. While the increase in timeout responses remained detectible during washout, all other DFP-related alterations in 5C-SRTT performance abated. When the demands of the task were increased by the presentation of variable intertrial intervals, premature responses were also elevated in DFP-treated rats during the washout period. These results indicate that repeated exposures to subthreshold doses of DFP lead to reversible impairments in sustained attention as well as persistent impairments of inhibitory response control in rats.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States; Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States.
| | - Patrick M Callahan
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States; Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States
| | - Wayne D Beck
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, United States
| | - Leah Vandenhuerk
- Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States
| | - Samantha Sinha
- Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States
| | - Kristy Bouchard
- Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States
| | - Rose Schade
- Small Animal Behavior Core, Georgia Regents University, Augusta, GA 30912, United States
| | - Jennifer L Waller
- Department of Biostatistics, Georgia Regents University, Augusta, GA 30912, United States
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Koelsch G, Meltzer LT, Yoshimura RF, Terry AV, Callahan PM, Bilcer G, Ng J, Ng R, Gee KW, Kelly TA. P4‐373: APN1125: A NOVEL A7 NICOTINIC ACETYLCHOLINE RECEPTOR PARTIAL AGONIST. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.07.142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Gerald Koelsch
- CoMentis, Inc.South San FranciscoCaliforniaUnited States
| | | | | | - Alvin V. Terry
- Prime Behavior Testing Laboratories, Inc.EvansGeorgiaUnited States
| | | | | | - John Ng
- CoMentis, Inc.South San FranciscoCaliforniaUnited States
| | - Raymond Ng
- CoMentis, Inc.South San FranciscoCaliforniaUnited States
| | - Kelvin W. Gee
- University of California, IrvineIrvineCaliforniaUnited States
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Gao J, Adam BL, Terry AV. Evaluation of nicotine and cotinine analogs as potential neuroprotective agents for Alzheimer's disease. Bioorg Med Chem Lett 2014; 24:1472-8. [PMID: 24581918 DOI: 10.1016/j.bmcl.2014.02.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 01/27/2014] [Accepted: 02/04/2014] [Indexed: 02/05/2023]
Abstract
The currently available therapies for Alzheimer's disease (AD) and related forms of dementia are limited by modest efficacy, adverse side effects, and the fact that they do not prevent the relentless progression of the illness. The purpose of the studies described here was to investigate the neuroprotective effects of the nicotine metabolite cotinine as well as a small series of cotinine and nicotine analogs (including stereoisomers) and to compare their effects to the four clinically prescribed AD therapies.
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Affiliation(s)
- Jie Gao
- Department of Pharmacology and Toxicology, CB-3545, Georgia Regents University, 1120 Fifteenth Street, Augusta, GA 30912-2450, United States
| | - Bao-Ling Adam
- Department of Pharmacology and Toxicology, CB-3545, Georgia Regents University, 1120 Fifteenth Street, Augusta, GA 30912-2450, United States
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, CB-3545, Georgia Regents University, 1120 Fifteenth Street, Augusta, GA 30912-2450, United States.
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