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Positive allosteric modulation of the α7 nicotinic acetylcholine receptor as a treatment for cognitive deficits after traumatic brain injury. PLoS One 2019; 14:e0223180. [PMID: 31581202 PMCID: PMC6776323 DOI: 10.1371/journal.pone.0223180] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 09/16/2019] [Indexed: 11/19/2022] Open
Abstract
Cognitive impairments are a common consequence of traumatic brain injury (TBI). The hippocampus is a subcortical structure that plays a key role in the formation of declarative memories and is highly vulnerable to TBI. The α7 nicotinic acetylcholine receptor (nAChR) is highly expressed in the hippocampus and reduced expression and function of this receptor are linked with cognitive impairments in Alzheimer's disease and schizophrenia. Positive allosteric modulation of α7 nAChRs with AVL-3288 enhances receptor currents and improves cognitive functioning in naïve animals and healthy human subjects. Therefore, we hypothesized that targeting the α7 nAChR with the positive allosteric modulator AVL-3288 would enhance cognitive functioning in the chronic recovery period of TBI. To test this hypothesis, adult male Sprague Dawley rats received moderate parasagittal fluid-percussion brain injury or sham surgery. At 3 months after recovery, animals were treated with vehicle or AVL-3288 at 30 min prior to cue and contextual fear conditioning and the water maze task. Treatment of TBI animals with AVL-3288 rescued learning and memory deficits in water maze retention and working memory. AVL-3288 treatment also improved cue and contextual fear memory when tested at 24 hr and 1 month after training, when TBI animals were treated acutely just during fear conditioning at 3 months post-TBI. Hippocampal atrophy but not cortical atrophy was reduced with AVL-3288 treatment in the chronic recovery phase of TBI. AVL-3288 application to acute hippocampal slices from animals at 3 months after TBI rescued basal synaptic transmission deficits and long-term potentiation (LTP) in area CA1. Our results demonstrate that AVL-3288 improves hippocampal synaptic plasticity, and learning and memory performance after TBI in the chronic recovery period. Enhancing cholinergic transmission through positive allosteric modulation of the α7 nAChR may be a novel therapeutic to improve cognition after TBI.
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de la Tremblaye PB, Bondi CO, Lajud N, Cheng JP, Radabaugh HL, Kline AE. Galantamine and Environmental Enrichment Enhance Cognitive Recovery after Experimental Traumatic Brain Injury But Do Not Confer Additional Benefits When Combined. J Neurotrauma 2016; 34:1610-1622. [PMID: 27806662 DOI: 10.1089/neu.2016.4790] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Environmental enrichment (EE) enhances cognition after traumatic brain injury (TBI). Galantamine (GAL) is an acetylcholinesterase inhibitor that also may promote benefits. Hence, the aims of this study were to assess the efficacy of GAL alone (standard [STD] housing) and in combination with EE in adult male rats after TBI. The hypothesis was that both therapies would confer motor, cognitive, and histological benefits when provided singly, but that their combination would be more efficacious. Anesthetized rats received a controlled cortical impact or sham injury, then were randomly assigned to receive GAL (1, 2, or 3 mg/kg; intraperitoneally [i.p.]) or saline vehicle (VEH; 1 mL/kg; i.p.) beginning 24 h after surgery and once daily for 21 days (experiment 1). Motor (beam-balance/walk) and cognitive (Morris water maze [MWM]) assessments were conducted on post-operative Days 1-5 and 14-19, respectively. Cortical lesion volumes were quantified on Day 21. Sham controls were better versus all TBI groups. No differences in motor function or lesion volumes were observed among the TBI groups (p > 0.05). In contrast, GAL (2 mg/kg) enhanced MWM performance versus VEH and GAL (1 and 3 mg/kg; p < 0.05). In experiment 2, GAL (2 mg/kg) or VEH was combined with EE and the data were compared with the STD-housed groups from experiment 1. EE alone enhanced motor performance over the VEH-treated and GAL-treated (2 mg/kg) STD-housed groups (p < 0.05). Moreover, both EE groups (VEH or GAL) facilitated spatial learning and reduced lesion size versus STD + VEH controls (p < 0.05). No additional benefits were observed with the combination paradigm, which does not support the hypothesis. Overall, the data demonstrate that EE and once daily GAL (2 mg/kg) promote cognitive recovery after TBI. Importantly, the combined therapies did not negatively affect outcome and thus this therapeutic protocol may have clinical utility.
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Affiliation(s)
- Patricia B de la Tremblaye
- 1 Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Corina O Bondi
- 1 Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania.,3 Department of Neurobiology, University of Pittsburgh , Pittsburgh, Pennsylvania.,4 Center for Neuroscience, University of Pittsburgh , Pittsburgh, Pennsylvania.,5 Center for the Neural Basis of Cognition, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Naima Lajud
- 1 Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania.,6 Division of Neuroscience, Biomedical Research Center of Michoacán, Mexican Social Security Institute , Morelia, Mexico
| | - Jeffrey P Cheng
- 1 Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Hannah L Radabaugh
- 1 Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Anthony E Kline
- 1 Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania.,4 Center for Neuroscience, University of Pittsburgh , Pittsburgh, Pennsylvania.,5 Center for the Neural Basis of Cognition, University of Pittsburgh , Pittsburgh, Pennsylvania.,7 Department of Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania.,8 Department of Psychology, University of Pittsburgh , Pittsburgh, Pennsylvania
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Tweedie D, Fukui K, Li Y, Yu QS, Barak S, Tamargo IA, Rubovitch V, Holloway HW, Lehrmann E, Wood WH, Zhang Y, Becker KG, Perez E, Van Praag H, Luo Y, Hoffer BJ, Becker RE, Pick CG, Greig NH. Cognitive Impairments Induced by Concussive Mild Traumatic Brain Injury in Mouse Are Ameliorated by Treatment with Phenserine via Multiple Non-Cholinergic and Cholinergic Mechanisms. PLoS One 2016; 11:e0156493. [PMID: 27254111 PMCID: PMC4890804 DOI: 10.1371/journal.pone.0156493] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/16/2016] [Indexed: 11/18/2022] Open
Abstract
Traumatic brain injury (TBI), often caused by a concussive impact to the head, affects an estimated 1.7 million Americans annually. With no approved drugs, its pharmacological treatment represents a significant and currently unmet medical need. In our prior development of the anti-cholinesterase compound phenserine for the treatment of neurodegenerative disorders, we recognized that it also possesses non-cholinergic actions with clinical potential. Here, we demonstrate neuroprotective actions of phenserine in neuronal cultures challenged with oxidative stress and glutamate excitotoxicity, two insults of relevance to TBI. These actions translated into amelioration of spatial and visual memory impairments in a mouse model of closed head mild TBI (mTBI) two days following cessation of clinically translatable dosing with phenserine (2.5 and 5.0 mg/kg BID x 5 days initiated post mTBI) in the absence of anti-cholinesterase activity. mTBI elevated levels of thiobarbituric acid reactive substances (TBARS), a marker of oxidative stress. Phenserine counteracted this by augmenting homeostatic mechanisms to mitigate oxidative stress, including superoxide dismutase [SOD] 1 and 2, and glutathione peroxidase [GPx], the activity and protein levels of which were measured by specific assays. Microarray analysis of hippocampal gene expression established that large numbers of genes were exclusively regulated by each individual treatment with a substantial number of them co-regulated between groups. Molecular pathways associated with lipid peroxidation were found to be regulated by mTBI, and treatment of mTBI animals with phenserine effectively reversed injury-induced regulations in the ‘Blalock Alzheimer’s Disease Up’ pathway. Together these data suggest that multiple phenserine-associated actions underpin this compound’s ability to ameliorate cognitive deficits caused by mTBI, and support the further evaluation of the compound as a therapeutic for TBI.
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Affiliation(s)
- David Tweedie
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Koji Fukui
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
- Division of Bioscience and Engineering, Shibaura Institute of Technology, Saitama 3378570, Japan
| | - Yazhou Li
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Qian-sheng Yu
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Shani Barak
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 69978 Israel
| | - Ian A. Tamargo
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Vardit Rubovitch
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 69978 Israel
| | - Harold W. Holloway
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Elin Lehrmann
- Laboratory of Genetics and Genomics, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - William H. Wood
- Laboratory of Genetics and Genomics, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Yongqing Zhang
- Laboratory of Genetics and Genomics, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Kevin G. Becker
- Laboratory of Genetics and Genomics, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Evelyn Perez
- Laboratory of Behavioral Neuroscience, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Henriette Van Praag
- Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
| | - Yu Luo
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, United States of America
| | - Barry J. Hoffer
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, United States of America
| | - Robert E. Becker
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
- Independent Researcher, 7123 Pinebrook Road, Park City, UT 94098, United States of America
| | - Chaim G. Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 69978 Israel
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, 69978 Israel
| | - Nigel H. Greig
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, United States of America
- * E-mail:
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Shin SS, Dixon CE. Alterations in Cholinergic Pathways and Therapeutic Strategies Targeting Cholinergic System after Traumatic Brain Injury. J Neurotrauma 2015; 32:1429-40. [PMID: 25646580 DOI: 10.1089/neu.2014.3445] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traumatic brain injury (TBI) results in varying degrees of disability in a significant number of persons annually. The mechanisms of cognitive dysfunction after TBI have been explored in both animal models and human clinical studies for decades. Dopaminergic, serotonergic, and noradrenergic dysfunction has been described in many previous reports. In addition, cholinergic dysfunction has also been a familiar topic among TBI researchers for many years. Although pharmacological agents that modulate cholinergic neurotransmission have been used with varying degrees of success in previous studies, improving their function and maximizing cognitive recovery is an ongoing process. In this article, we review the previous findings on the biological mechanism of cholinergic dysfunction after TBI. In addition, we describe studies that use both older agents and newly developed agents as candidates for targeting cholinergic neurotransmission in future studies.
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Affiliation(s)
- Samuel S Shin
- 1 Brain Trauma Research Center, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Department of Neurological Surgery, University of Pittsburgh , Pittsburgh, Pennsylvania.,3 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - C Edward Dixon
- 1 Brain Trauma Research Center, University of Pittsburgh , Pittsburgh, Pennsylvania.,2 Department of Neurological Surgery, University of Pittsburgh , Pittsburgh, Pennsylvania.,3 Safar Center for Resuscitation Research, University of Pittsburgh , Pittsburgh, Pennsylvania.,4 Veterans Affairs Pittsburgh Healthcare System , Pittsburgh, Pennsylvania
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Shaw KE, Bondi CO, Light SH, Massimino LA, McAloon RL, Monaco CM, Kline AE. Donepezil is ineffective in promoting motor and cognitive benefits after controlled cortical impact injury in male rats. J Neurotrauma 2013; 30:557-64. [PMID: 23227953 DOI: 10.1089/neu.2012.2782] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The acetylcholinesterase (AChE) inhibitor donepezil is used as a therapy for Alzheimer's disease and has been recommended as a treatment for enhancing attention and memory after traumatic brain injury (TBI). Although select clinical case studies support the use of donepezil for enhancing cognition, there is a paucity of experimental TBI studies assessing the potential efficacy of this pharmacotherapy. Hence, the aim of this pre-clinical study was to evaluate several doses of donepezil to determine its effect on functional outcome after TBI. Ninety anesthetized adult male rats received a controlled cortical impact (CCI; 2.8 mm cortical depth at 4 m/sec) or sham injury, and then were randomly assigned to six TBI and six sham groups (donepezil 0.25, 0.5, 1.0, 2.0, or 3.0 mg/kg, and saline vehicle 1.0 mL/kg). Treatments began 24 h after surgery and were administered i.p. once daily for 19 days. Function was assessed by motor (beam balance/walk) and cognitive (Morris water maze) tests on days 1-5 and 14-19, respectively. No significant differences were observed among the sham control groups in any evaluation, regardless of dose, and therefore the data were pooled. Furthermore, no significant differences were revealed among the TBI groups in acute neurological assessments (e.g., righting reflex), suggesting that all groups received the same level of injury severity. None of the five doses of donepezil improved motor or cognitive function relative to vehicle-treated controls. Moreover, the two highest doses significantly impaired beam-balance (3.0 mg/kg), beam-walk (2.0 mg/kg and 3.0 mg/kg), and cognitive performance (3.0 mg/kg) versus vehicle. These data indicate that chronic administration of donepezil is not only ineffective in promoting functional improvement after moderate CCI injury, but depending on the dose is actually detrimental to the recovery process. Further work is necessary to determine if other AChE inhibitors exert similar effects after TBI.
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Affiliation(s)
- Kaitlyn E Shaw
- Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15213, USA
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Kokiko ON, Hamm RJ. A review of pharmacological treatments used in experimental models of traumatic brain injury. Brain Inj 2008; 21:259-74. [PMID: 17453754 DOI: 10.1080/02699050701209964] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PRIMARY OBJECTIVE We provide a review of recent chronic and delayed rehabilitative pharmacological treatments examined in experimental models of traumatic brain injury. There is a specific emphasis on studies aiming to enhance cognitive recovery. MAIN OUTCOMES AND RESULTS Decreased neuronal activity is believed to contribute to persistent cognitive disabilities. Neurotransmitter based rehabilitative treatments that increase neuronal activity may assist in the recovery of cognitive function. However, timing and dosage of drug treatment are influential in cognitive enhancement. Drug treatments that affect single and multiple neurotransmitter systems have the ability to significantly influence recovery of function following brain injury. CONCLUSIONS Understanding the relationship between neural disturbances and functional deficits following brain injury is challenging. Cognitive impairment may be the result of a single event or multiple events that occur after the initial insult. Increasing neuronal activity during the chronic phase of injury seems to be an effective treatment strategy for facilitating cognitive recovery. Pharmacological agents do not necessarily display the same effects in an injured brain as in a non-injured brain. Thus, further research is needed to establish the effectiveness of rehabilitative drug treatments.
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Affiliation(s)
- Olga N Kokiko
- Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, USA
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Arciniegas DB, Topkoff JL. Applications of the P50 evoked response to the evaluation of cognitive impairments after traumatic brain injury. Phys Med Rehabil Clin N Am 2004; 15:177-203, viii. [PMID: 15029905 DOI: 10.1016/s1047-9651(03)00104-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This article reviews the applications of the P50 evoked response to paired auditory stimuli (P50 ERP) in the study and evaluation of cognitive impairments after traumatic brain injury (TBI). The cholinergic hypothesis of cognitive impairment after TBI and the relationship of impaired auditory sensory gating to that hypothesis are presented. The neurobiology of impaired sensory gating, the relationship of that neurobiology to the P50 ERP, and the principles of P50 ERP recording are discussed. Studies of the P50 ERP among patients with persistent cognitive complaints after TBI are reviewed. Finally, possible clinical applications and limitations of the P50 ERP in the study, evaluation, and treatment of patients with cognitive impairments after TBI are offered.
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Affiliation(s)
- David B Arciniegas
- Neuropsychiatry Service, Department of Psychiatry, University of Colorado School of Medicine, Campus Box C28-68, 4200 East Ninth Avenue, Denver, CO 80262, USA.
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8
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Abstract
Cognitive impairments are among the most common neuropsychiatric sequelae of traumatic brain injury at all levels of severity. Cerebral cholinergic neurons and their ascending projections are particularly vulnerable to acute and chronic traumatically mediated dysfunction. In light of the important role of acetylcholine in arousal, attention, memory, and other aspects of cognition, cerebral cholinergic systems contribute to and may also be a target for pharmacologic remediation among individuals with post-traumatic cognitive impairments. This article will review the evidence in support of this hypothesis. Evidence of relatively selective damage to cholinergic injury, the development of persistent anticholinergic sensitivity, and the effects of cholinergic augmentation on memory performance are presented first. Thereafter, neuropathologic, electrophysiologic, and pharmacologic evidence of cholinergic dysfunction after traumatic brain injury in humans is reviewed. Finally, future directions for investigation of the cholinergic hypothesis and possible clinical applications of this information are discussed.
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Affiliation(s)
- David B Arciniegas
- Brain Injury Rehabilitation Unit, Spalding Rehabilitation Hospital, Aurora, CO 80011, USA.
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Härtig W, Bauer A, Brauer K, Grosche J, Hortobágyi T, Penke B, Schliebs R, Harkany T. Functional recovery of cholinergic basal forebrain neurons under disease conditions: old problems, new solutions? Rev Neurosci 2003; 13:95-165. [PMID: 12160262 DOI: 10.1515/revneuro.2002.13.2.95] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recognition of the involvement of cholinergic neurons in the modulation of cognitive functions and their severe dysfunction in neurodegenerative disorders, such as Alzheimer's disease, initiated immense research efforts aimed at unveiling the anatomical organization and cellular characteristics of the basal forebrain (BFB) cholinergic system. Concomitant with our unfolding knowledge about the structural and functional complexity of the BFB cholinergic projection system, multiple pharmacological strategies were introduced to rescue cholinergic nerve cells from noxious attacks; however, a therapeutic breakthrough is still awaited. In this review, we collected recent findings that significantly contributed to our better understanding of cholinergic functions under disease conditions, and to the design of effective means to restore lost or damaged cholinergic functions. To this end, we first provide a brief survey of the neuroanatomical organization of BFB nuclei with emphasis on major evolutionary differences among mammalian species, in particular rodents and primates, and discuss limitations of the translation of experimental data to human therapeutic applications. Subsequently, we summarize the involvement of cholinergic dysfunction in the pathogenesis of severe neurological conditions, including stroke, traumatic brain injury, virus encephalitis and Alzheimer's disease, and emphasize the critical role of pro-inflammatory cytokines as common mediators of cholinergic neuronal damage. Moreover, we review leading functional concepts on the limited recovery of cholinergic neurons and their impaired plastic re-modeling, as well as on the hampered interplay of the ascending cholinergic and monoaminergic projection systems under neurodegenerative conditions. In addition, recent advances in the dynamic labeling of living cholinergic neurons by fluorochromated antibodies, referred to as in vivo labeling, and novel neuroimaging approaches as potential diagnostic tools of progressive cholinergic decline are surveyed. Finally, the potential of cell replacement strategies using embryonic and adult stem cells, and multipotent neural progenitors, as a means to recover damaged cholinergic functions, is discussed.
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Affiliation(s)
- Wolfgang Härtig
- Department of Neurochemistry, Paul Flechsig Institute for Brain Research, University of Leipzig, Germany
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Csernansky JG, Bardgett ME, Dong H, Humphrey W, Wang L. Hippocampal structure and the action of cholinomimetic drugs. Drug Dev Res 2002. [DOI: 10.1002/ddr.10106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Murdoch I, Nicoll JAR, Graham DI, Dewar D. Nucleus basalis of Meynert pathology in the human brain after fatal head injury. J Neurotrauma 2002; 19:279-84. [PMID: 11898797 DOI: 10.1089/08977150252807018] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dysfunction of the basal forebrain cholinergic system has been hypothesized to contribute to deficits of memory and cognition after head injury. We have previously reported reduced levels of choline acetyltransferase activity in the cerebral cortex of patients who died after a head injury, demonstrating that there is a loss of cortical cholinergic innervation. In the present study, we examined the nucleus basalis of Meynert (NBM), which provides cortical cholinergic innervation, in fatally head-injured patients and in controls. The majority of head-injured patients had histological evidence of neuronal damage in the NBM, which was due to mechanical distortion of the tissue and/or ischemic damage. The findings demonstrate that the NBM is vulnerable after severe head injury and that secondary insults play an important role in the damage. Thus, both neuronal perikarya and terminals of the basal forebrain cholinergic system are damaged after human fatal head injury. This damage may contribute to persisting dysfunction of memory and cognition in head-injured patients who survive.
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Affiliation(s)
- Iain Murdoch
- The Wellcome Surgical Institute, University of Glasgow, United Kingdom
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Schmidt RH, Scholten KJ, Maughan PH. Time course for recovery of water maze performance and central cholinergic innervation after fluid percussion injury. J Neurotrauma 1999; 16:1139-47. [PMID: 10619193 DOI: 10.1089/neu.1999.16.1139] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study further investigates the possible connection between postconcussive cognitive impairment and damage to forebrain cholinergic innervation. Moderate parasagittal fluid percussion injury was delivered to adult male rats. Water maze performance and synaptosomal choline uptake was measured at various times following injury. Water maze learning was severely impaired between 1 and 5 weeks, but recovered to normal by 10 weeks. Synaptosomal choline uptake was significantly decreased by 15-27% in the ipsilateral hippocampus and parietal cortex 3 and 7 days following injury, but not by 3 weeks or thereafter. Choline acetyltransferase was also significantly decreased in the ipsilateral cortex at 3 and 7 days with subsequent recovery. This study shows that parasagittal fluid percussion injury causes significant impairment in water maze learning and ipsilateral forebrain cholinergic innervation. Both of these parameters recover spontaneously, but with different time courses.
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Affiliation(s)
- R H Schmidt
- Department of Neurosurgery, University of Utah, Salt Lake City 84132, USA.
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13
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Flitman SS. Tranquilizers, Stimulants, and Enhancers of Cognition. Phys Med Rehabil Clin N Am 1999. [DOI: 10.1016/s1047-9651(18)30206-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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McIntosh TK, Juhler M, Wieloch T. Novel pharmacologic strategies in the treatment of experimental traumatic brain injury: 1998. J Neurotrauma 1998; 15:731-69. [PMID: 9814632 DOI: 10.1089/neu.1998.15.731] [Citation(s) in RCA: 256] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The mechanisms underlying secondary or delayed cell death following traumatic brain injury are poorly understood. Recent evidence from experimental models suggests that widespread neuronal loss is progressive and continues in selectively vulnerable brain regions for months to years after the initial insult. The mechanisms underlying delayed cell death are believed to result, in part, from the release or activation of endogenous "autodestructive" pathways induced by the traumatic injury. The development of sophisticated neurochemical, histopathological and molecular techniques to study animal models of TBI have enabled researchers to begin to explore the cellular and genomic pathways that mediate cell damage and death. This new knowledge has stimulated the development of novel therapeutic agents designed to modify gene expression, synthesis, release, receptor or functional activity of these pathological factors with subsequent attenuation of cellular damage and improvement in behavioral function. This article represents a compendium of recent studies suggesting that modification of post-traumatic neurochemical and cellular events with targeted pharmacotherapy can promote functional recovery following traumatic injury to the central nervous system.
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Affiliation(s)
- T K McIntosh
- Department of Neurosurgery, University of Pennsylvania, Philadelphia 19104-6316, USA
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