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Santiago J, Kreutzer J, Bossink E, Kallio P, le Feber J. Oxygen gradient generator to improve in vitro modeling of ischemic stroke. Front Neurosci 2023; 17:1110083. [PMID: 37056304 PMCID: PMC10086255 DOI: 10.3389/fnins.2023.1110083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 03/08/2023] [Indexed: 03/30/2023] Open
Abstract
IntroductionIn the core of a brain infarct, perfusion is severely impeded, and neuronal death occurs within minutes. In the penumbra, an area near the core with more remaining perfusion, cells initially remain viable, but activity is significantly reduced. In principle, the penumbra can be saved if reperfusion is established on time, making it a promising target for treatment. In vitro models with cultured neurons on microelectrode arrays (MEAs) provide a useful tool to investigate how ischemic stroke affects neuronal functioning. These models tend to be uniform, focusing on the isolated penumbra, and typically lack adjacent regions such as a core and unaffected regions (normal perfusion). However, processes in these regions may affect neuronal functioning and survival in the penumbra.Materials and methodsHere, we designed, fabricated, and characterized a cytocompatible device that generates an oxygen gradient across in vitro neuronal cultures to expose cells to hypoxia of various depths from near anoxia to near normoxia. This marks a step in the path to mimic core, penumbra, and healthy tissue, and will facilitate better in vitro modeling of ischemic stroke.ResultsThe generator forms a stable and reproducible gradient within 30 min. Oxygen concentrations at the extremes are adjustable in a physiologically relevant range. Application of the generator did not negatively affect electrophysiological recordings or the viability of cultures, thus confirming the cytocompatibility of the device.DiscussionThe developed device is able to impose an oxygen gradient on neuronal cultures and may enrich in vitro stroke models.
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Affiliation(s)
- João Santiago
- Clinical Neurophysiology, University of Twente, Enschede, Netherlands
| | - Joose Kreutzer
- Micro and Nanosystems Research Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Elsbeth Bossink
- Biomedical and Environmental Sensor Systems, University of Twente, Enschede, Netherlands
| | - Pasi Kallio
- Micro and Nanosystems Research Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Joost le Feber
- Clinical Neurophysiology, University of Twente, Enschede, Netherlands
- *Correspondence: Joost le Feber,
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Wang X, Cui L, Ji X. Cognitive impairment caused by hypoxia: from clinical evidences to molecular mechanisms. Metab Brain Dis 2022; 37:51-66. [PMID: 34618295 DOI: 10.1007/s11011-021-00796-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/09/2021] [Indexed: 12/23/2022]
Abstract
Hypoxia is a state of reduced oxygen supply and excessive oxygen consumption. According to the duration of hypoxic period, it can be classified as acute and chronic hypoxia. Both acute and chronic hypoxia could induce abundant neurological deficits. Although there have been significant advances in the pathophysiological injuries, few studies have focused on the cognitive dysfunction. In this review, we focused on the clinical evidences and molecular mechanisms of cognitive impairment under acute and chronic hypoxia. Hypoxia can impair several cognitive domains such as attention, learning and memory, procession speed and executive function, which are similar in acute and chronic hypoxia. The severity of cognitive deficit correlates with the duration and degree of hypoxia. Recovery can be achieved after acute hypoxia, while sequelae or even dementia can be observed after chronic hypoxia, perhaps due to the different molecular mechanisms. Cardiopulmonary compensatory response, glycolysis, oxidative stress, calcium overload, adenosine, mitochondrial disruption, inflammation and excitotoxicity contribute to the molecular mechanisms of cognitive deficit after acute hypoxia. During the chronic stage of hypoxia, different adaptive responses, impaired neurovascular coupling, apoptosis, transcription factors-mediated inflammation, as well as Aβ accumulation and tau phosphorylation account for the neurocognitive deficit. Moreover, brain structural changes with hippocampus and cortex atrophy, ventricle enlargement, senile plaque and neurofibrillary tangle deposition can be observed under chronic hypoxia rather than acute hypoxia.
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Affiliation(s)
- Xiaoyin Wang
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Lili Cui
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Xunming Ji
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.
- Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, No 45, Changchun Street, Beijing, 100053, Xicheng District, China.
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3
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Watts M, Williams G, Lu J, Nithianantharajah J, Claudianos C. MicroRNA-210 Regulates Dendritic Morphology and Behavioural Flexibility in Mice. Mol Neurobiol 2021; 58:1330-1344. [PMID: 33165828 DOI: 10.1007/s12035-020-02197-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/30/2020] [Indexed: 01/05/2023]
Abstract
MicroRNAs are known to be critical regulators of neuronal plasticity. The highly conserved, hypoxia-regulated microRNA-210 (miR-210) has been shown to be associated with long-term memory in invertebrates and dysregulated in neurodevelopmental and neurodegenerative disease models. However, the role of miR-210 in mammalian neuronal function and cognitive behaviour remains unexplored. Here we generated Nestin-cre-driven miR-210 neuronal knockout mice to characterise miR-210 regulation and function using in vitro and in vivo methods. We identified miR-210 localisation throughout neuronal somas and dendritic processes and increased levels of mature miR-210 in response to neural activity in vitro. Loss of miR-210 in neurons resulted in higher oxidative phosphorylation and ROS production following hypoxia and increased dendritic arbour density in hippocampal cultures. Additionally, miR-210 knockout mice displayed altered behavioural flexibility in rodent touchscreen tests, particularly during early reversal learning suggesting processes underlying updating of information and feedback were impacted. Our findings support a conserved, activity-dependent role for miR-210 in neuroplasticity and cognitive function.
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Affiliation(s)
- Michelle Watts
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Gabrielle Williams
- School of Psychological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Jing Lu
- School of Psychological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Jess Nithianantharajah
- The Florey Institute of Neuroscience & Mental Health, Melbourne, VIC, 3052, Australia.
- Florey Department of Neuroscience, University of Melbourne, Melbourne, VIC, 3010, Australia.
| | - Charles Claudianos
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.
- Centre for Mental Health Research, The Australian National University, Canberra, ACT, 0200, Australia.
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4
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Nutma S, le Feber J, Hofmeijer J. Neuroprotective Treatment of Postanoxic Encephalopathy: A Review of Clinical Evidence. Front Neurol 2021; 12:614698. [PMID: 33679581 PMCID: PMC7930064 DOI: 10.3389/fneur.2021.614698] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/19/2021] [Indexed: 12/24/2022] Open
Abstract
Postanoxic encephalopathy is the key determinant of death or disability after successful cardiopulmonary resuscitation. Animal studies have provided proof-of-principle evidence of efficacy of divergent classes of neuroprotective treatments to promote brain recovery. However, apart from targeted temperature management (TTM), neuroprotective treatments are not included in current care of patients with postanoxic encephalopathy after cardiac arrest. We aimed to review the clinical evidence of efficacy of neuroprotective strategies to improve recovery of comatose patients after cardiac arrest and to propose future directions. We performed a systematic search of the literature to identify prospective, comparative clinical trials on interventions to improve neurological outcome of comatose patients after cardiac arrest. We included 53 studies on 21 interventions. None showed unequivocal benefit. TTM at 33 or 36°C and adrenaline (epinephrine) are studied most, followed by xenon, erythropoietin, and calcium antagonists. Lack of efficacy is associated with heterogeneity of patient groups and limited specificity of outcome measures. Ongoing and future trials will benefit from systematic collection of measures of baseline encephalopathy and sufficiently powered predefined subgroup analyses. Outcome measurement should include comprehensive neuropsychological follow-up, to show treatment effects that are not detectable by gross measures of functional recovery. To enhance translation from animal models to patients, studies under experimental conditions should adhere to strict methodological and publication guidelines.
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Affiliation(s)
- Sjoukje Nutma
- Department of Neurology, Medisch Spectrum Twente, Enschede, Netherlands
- Clinical Neurophysiology, University of Twente, Enschede, Netherlands
| | - Joost le Feber
- Clinical Neurophysiology, University of Twente, Enschede, Netherlands
| | - Jeannette Hofmeijer
- Clinical Neurophysiology, University of Twente, Enschede, Netherlands
- Department of Neurology, Rijnstate Hospital Arnhem, Arnhem, Netherlands
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Wolff MD, Farrell JS, Scantlebury MH, Teskey GC. Dynamic oxygen changes during status epilepticus and subsequent endogenous kindling. Epilepsia 2020; 61:1515-1527. [PMID: 32478859 PMCID: PMC7496277 DOI: 10.1111/epi.16554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Brain tissue oxygen (partial oxygen pressure [pO2 ]) levels are tightly regulated to stay within the normoxic zone, with deviations on either side resulting in impaired brain function. Whereas pathological events such as ischemic attacks and brief seizures have previously been shown to result in pO2 levels well below the normoxic zone, oxygen levels during prolonged status epilepticus (SE) and the subsequent endogenous kindling period are unknown. METHODS We utilized two models of acquired temporal lobe epilepsy in rats: intrahippocampal kainic acid infusion and prolonged perforant pathway stimulation. Local tissue oxygen was measured in the dorsal hippocampus using an optode during and for several weeks following SE. RESULTS We observed hyperoxia in the hippocampus during induced SE in both models. Following termination of SE, 88% of rats initiated focal self-generated spiking activity in the hippocampus within the first 7 days, which was associated with dynamic oxygen changes. Self-generated and recurring epileptiform activity subsequently organized into higher-frequency bursts that became progressively longer and were ultimately associated with behavioral seizures that became more severe with time and led to postictal hypoxia. SIGNIFICANCE Induced SE and self-generated recurrent epileptiform activity can have profound and opposing effects on brain tissue oxygenation that may serve as a biomarker for ongoing pathological activity in the brain.
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Affiliation(s)
- Marshal D. Wolff
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
| | - Jordan S. Farrell
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Department of NeurosurgeryStanford UniversityStanfordCaliforniaUSA
| | - Morris H. Scantlebury
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Departments of Pediatrics and Clinical NeurosciencesUniversity of CalgaryCalgaryAlbertaCanada
- Alberta Children's Hospital Research InstituteUniversity of CalgaryCalgaryAlbertaCanada
| | - G. Campbell Teskey
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Alberta Children's Hospital Research InstituteUniversity of CalgaryCalgaryAlbertaCanada
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Tang W, Xin X, O'Connor M, Zhang N, Lai B, Man HY, Xie Y, Wei Y. Transient sublethal hypoxia in neonatal rats causes reduced dendritic spines, aberrant synaptic plasticity, and impairments in memory. J Neurosci Res 2020; 98:1588-1604. [PMID: 32495348 DOI: 10.1002/jnr.24652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/08/2020] [Accepted: 05/10/2020] [Indexed: 01/06/2023]
Abstract
Hypoxic/ischemic insult, a leading cause of functional brain defects, has been extensively studied in both clinical and experimental animal research, including its etiology, neuropathogenesis, and pharmacological interventions. Transient sublethal hypoxia (TSH) is a common clinical occurrence in the perinatal period. However, its effect on early developing brains remains poorly understood. The present study was designed to investigate the effect of TSH on the dendrite and dendritic spine formation, neuronal and synaptic activity, and cognitive behavior of early postnatal Day 1 rat pups. While TSH showed no obvious effect on gross brain morphology, neuron cell density, or glial activation in the hippocampus, we found transient hypoxia did cause significant changes in neuronal structure and function. In brains exposed to TSH, hippocampal neurons developed shorter and thinner dendrites, with decreased dendritic spine density, and reduced strength in excitatory synaptic transmission. Moreover, TSH-treated rats showed impaired cognitive performance in spatial learning and memory. Our findings demonstrate that TSH in newborn rats can cause significant impairments in synaptic formation and function, and long-lasting brain functional deficits. Therefore, this study provides a useful animal model for the study of TSH on early developing brains and to explore potential pharmaceutical interventions for patients subjected to TSH insult.
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Affiliation(s)
- Wenjie Tang
- Research Center for Translational Medicine & Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaoming Xin
- Shanghai University of Medicine and Health Sciences, Shanghai, China
| | | | - Nana Zhang
- Research Center for Translational Medicine & Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Bin Lai
- Institute of Brain science, Fudan University, Shanghai, China
| | - Heng-Ye Man
- Department of Biology, Boston University, Boston, MA, USA
| | - Yuanyun Xie
- National Clinic and Medicine Research Institute for Geriatric Diseases, Gannan Health Promotion and Translational Laboratory, The First Affiliated Hospital, Gannan University of Medical sciences, Ganzhou, China
| | - Youzhen Wei
- Research Center for Translational Medicine & Key Laboratory of Arrhythmias of the Ministry of Education of China, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
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7
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Muzzi L, Hassink G, Levers M, Jansman M, Frega M, Hofmeijer J, van Putten M, le Feber J. Mild stimulation improves neuronal survival in an in vitro model of the ischemic penumbra. J Neural Eng 2019; 17:016001. [DOI: 10.1088/1741-2552/ab51d4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Abstract
The brain is the most complex organ of the body, and many pathological processes underlying various brain disorders are poorly understood. Limited accessibility hinders observation of such processes in the in vivo brain, and experimental freedom is often insufficient to enable informative manipulations. In vitro preparations (brain slices or cultures of dissociated neurons) offer much better accessibility and reduced complexity and have yielded valuable new insights into various brain disorders. Both types of preparations have their advantages and limitations with regard to lifespan, preservation of in vivo brain structure, composition of cell types, and the link to behavioral outcome is often unclear in in vitro models. While these limitations hamper general usage of in vitro preparations to study, e.g., brain development, in vitro preparations are very useful to study neuronal and synaptic functioning under pathologic conditions. This chapter addresses several brain disorders, focusing on neuronal and synaptic functioning, as well as network aspects. Recent progress in the fields of brain circulation disorders, excitability disorders, and memory disorders will be discussed, as well as limitations of current in vitro models.
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9
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Catanese A, Garrido D, Walther P, Roselli F, Boeckers TM. Nutrient limitation affects presynaptic structures through dissociable Bassoon autophagic degradation and impaired vesicle release. J Cereb Blood Flow Metab 2018; 38:1924-1939. [PMID: 29972341 PMCID: PMC6259322 DOI: 10.1177/0271678x18786356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Acute mismatch between metabolic requirements of neurons and nutrients/growth factors availability characterizes several neurological conditions such as traumatic brain injury, stroke and hypoglycemia. Although the effects of this mismatch have been investigated at cell biological level, the effects on synaptic structure and function are less clear. Since synaptic activity is the most energy-demanding neuronal function and it is directly linked to neuronal networks functionality, we have explored whether nutrient limitation (NL) affects the ultrastructure, function and composition of pre and postsynaptic terminals. We show that upon NL, presynaptic terminals show disorganized vesicle pools and reduced levels of the active zone protein Bassoon (but not of Piccolo). Moreover, NL triggers an impaired vesicle release, which is reversed by re-administration of glucose but not by the blockade of autophagic or proteasomal protein degradation. This reveals a dissociable correlation between presynaptic architecture and vesicle release, since restoring vesicle fusion does not necessarily depend from the rescue of Bassoon levels. Thus, our data show that the presynaptic compartment is highly sensitive to NL and the rescue of presynaptic function requires re-establishment of the metabolic supply rather than preventing local protein degradation.
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Affiliation(s)
- Alberto Catanese
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany.,2 International Graduate School in Molecular Medicine Ulm (IGradU), Ulm University, Ulm, Germany
| | - Débora Garrido
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany.,2 International Graduate School in Molecular Medicine Ulm (IGradU), Ulm University, Ulm, Germany
| | - Paul Walther
- 3 Electron Microscopy Institute, Ulm University, Ulm, Germany
| | - Francesco Roselli
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany.,4 Department of Neurology, Ulm University, Ulm, Germany
| | - Tobias M Boeckers
- 1 Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
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10
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le Feber J, Dummer A, Hassink GC, van Putten MJAM, Hofmeijer J. Evolution of Excitation-Inhibition Ratio in Cortical Cultures Exposed to Hypoxia. Front Cell Neurosci 2018; 12:183. [PMID: 30018536 PMCID: PMC6037832 DOI: 10.3389/fncel.2018.00183] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/11/2018] [Indexed: 11/24/2022] Open
Abstract
In the core of a brain infarct, neuronal death occurs within minutes after loss of perfusion. In the penumbra, a surrounding area with some residual perfusion, neurons initially remain structurally intact, but hypoxia-induced synaptic failure impedes neuronal activity. Penumbral activity may recover or further deteriorate, reflecting cell death. Mechanisms leading to either outcome remain ill-understood, but may involve changes in the excitation to inhibition (E/I) ratio. The E/I ratio is determined by structural (relative densities of excitatory and inhibitory synapses) and functional factors (synaptic strengths). Clinical studies demonstrated excitability alterations in regions surrounding the infarct core. These may be related to structural E/I changes, but the effects of hypoxia /ischemia on structural connectivity have not yet been investigated, and the role of structural connectivity changes in excitability alterations remains unclear. We investigated the evolution of the structural E/I ratio and associated network excitability in cortical cultures exposed to severe hypoxia of varying duration. 6–12 h of hypoxia reduced the total synaptic density. In particular, the inhibitory synaptic density dropped significantly, resulting in an elevated E/I ratio. Initially, this does not lead to increased excitability due to hypoxia-induced synaptic failure. Increased excitability becomes apparent upon reoxygenation after 6 or 12 h, but not after 24 h. After 24 h of hypoxia, structural patterns of vesicular glutamate stainings change. This possibly reflects disassembly of excitatory synapses, and may account for the irreversible reduction of activity and stimulus responses seen after 24 h.
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Affiliation(s)
- Joost le Feber
- Clinical Neurophysiology, TechMed Centre, University of Twente, Enschede, Netherlands
| | - Anneloes Dummer
- Clinical Neurophysiology, TechMed Centre, University of Twente, Enschede, Netherlands
| | - Gerco C Hassink
- Clinical Neurophysiology, TechMed Centre, University of Twente, Enschede, Netherlands.,Biomedical Signals and Systems, TechMed Centre, University of Twente, Enschede, Netherlands
| | - Michel J A M van Putten
- Clinical Neurophysiology, TechMed Centre, University of Twente, Enschede, Netherlands.,Department of Clinical Neurophysiology, Medisch Spectrum Twente, Enschede, Netherlands
| | - Jeannette Hofmeijer
- Clinical Neurophysiology, TechMed Centre, University of Twente, Enschede, Netherlands.,Department of Neurology, Rijnstate Hospital, Arnhem, Netherlands
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Watts ME, Pocock R, Claudianos C. Brain Energy and Oxygen Metabolism: Emerging Role in Normal Function and Disease. Front Mol Neurosci 2018; 11:216. [PMID: 29988368 PMCID: PMC6023993 DOI: 10.3389/fnmol.2018.00216] [Citation(s) in RCA: 202] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/01/2018] [Indexed: 01/09/2023] Open
Abstract
Dynamic metabolic changes occurring in neurons are critically important in directing brain plasticity and cognitive function. In other tissue types, disruptions to metabolism and the resultant changes in cellular oxidative state, such as increased reactive oxygen species (ROS) or induction of hypoxia, are associated with cellular stress. In the brain however, where drastic metabolic shifts occur to support physiological processes, subsequent changes to cellular oxidative state and induction of transcriptional sensors of oxidative stress likely play a significant role in regulating physiological neuronal function. Understanding the role of metabolism and metabolically-regulated genes in neuronal function will be critical in elucidating how cognitive functions are disrupted in pathological conditions where neuronal metabolism is affected. Here, we discuss known mechanisms regulating neuronal metabolism as well as the role of hypoxia and oxidative stress during normal and disrupted neuronal function. We also summarize recent studies implicating a role for metabolism in regulating neuronal plasticity as an emerging neuroscience paradigm.
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Affiliation(s)
- Michelle E Watts
- Queensland Brain Institute, The University of Queensland, St. Lucia, QLD, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Charles Claudianos
- Queensland Brain Institute, The University of Queensland, St. Lucia, QLD, Australia.,Centre for Mental Health Research, The Australian National University, Canberra, ACT, Australia
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Mei HF, Poonit N, Zhang YC, Ye CY, Cai HL, Yu CY, Zhou YH, Wu BB, Cai J, Cai XH. Activating adenosine A1 receptor accelerates PC12 cell injury via ADORA1/PKC/KATP pathway after intermittent hypoxia exposure. Mol Cell Biochem 2018; 446:161-170. [PMID: 29380238 DOI: 10.1007/s11010-018-3283-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 01/18/2018] [Indexed: 12/19/2022]
Abstract
Obstructive sleep apnea hypopnea syndrome (OSAHS) is associated with the neurocognitive deficits as a result of the neuronal cell injury. Previous studies have shown that adenosine A1 receptor (ADORA1) played an important role against hypoxia exposure, such as controlling the metabolic recovery in rat hippocampal slices and increasing the resistance in the combined effects of hypoxia and hypercapnia. However, little is known about whether ADORA1 takes part in the course of neuronal cell injury after intermittent hypoxia exposure which was the main pathological characteristic of OSAHS. The present study is performed to explore the underlying mechanism of neuronal cell injury which was induced by intermittent hypoxia exposure in PC12 cells. In our research, we find that the stimulation of the ADORA1 by CCPA accelerated the injury of PC12 cells as well as upregulated the expression of PKC, inwardly rectifying potassium channel 6.2(Kir6.2) and sulfonylurea receptor 1(SUR1) while inhibition of the ADORA1 by DPCPX alleviated the injury of PC12 cells as well as downregulated the expression of PKC, Kir6.2, and SUR1. Moreover, inhibition of the PKC by CHE, also mitigated the injury of PC12 cells, suppressed the Kir6.2 and SUR1 expressions induced by PKC. Taken together, our findings indicate that ADORA1 accelerated PC12 cells injury after intermittent hypoxia exposure via ADORA1/PKC/KATP signaling pathway.
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Affiliation(s)
- Hong-Fang Mei
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China.,Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310000, China
| | - Neha Poonit
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China
| | - Yi-Chun Zhang
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China
| | - Chu-Yuan Ye
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China
| | - Hui-Lin Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China
| | - Chen-Yi Yu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China
| | - Yong-Hai Zhou
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China
| | - Bei-Bei Wu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China
| | - Jun Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China. .,Department of Pediatrics, Children's Hospital Research Institute, The University of Louisville, Louisville, KY, USA.
| | - Xiao-Hong Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, The Second School of Medicine, Wenzhou Medical University, Wenzhou, 325027, China.
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13
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Fang C, Li Q, Min G, Liu M, Cui J, Sun J, Li L. MicroRNA-181c Ameliorates Cognitive Impairment Induced by Chronic Cerebral Hypoperfusion in Rats. Mol Neurobiol 2017; 54:8370-8385. [PMID: 27933582 DOI: 10.1007/s12035-016-0268-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/30/2016] [Indexed: 11/28/2022]
Abstract
Chronic cerebral hypoperfusion (CCH) characterized by global cerebral ischemia is an important risk factor contributing to the development of dementia. MicroRNAs (miRNAs) play important roles in the cellular adaptation to long-term ischemia/hypoxia by turning off or on the expression of target genes. MiR-181c is widely expressed in the nervous system, and tripartite motif 2 (TRIM2) is one of its target genes. In this work, we had identified that progressive spatial memory deficiency was induced in the bilateral common carotid artery occlusion (2-VO) rat models. Meanwhile, inhibition of miR-181c expression and upregulation of TRIM2 in the hippocampus of 2-VO rats were found accompanying with reduction in the dendritic branching and dendrite spine density of the hippocampal neurons. Viral vector-mediated miR-181c delivery might improve the cognitive deficiency via TRIM2 on neurofilament light (NF-L) ubiquitination resulting in remodeling of the hippocampal neurons as well as increase in N-methyl-D-aspartate receptor 1 (NR1) subunit cell surface expression. Meanwhile, miR-181c might rescue the cellular activity from ischemia/hypoxia. These results indicated a novel miRNA-mediated mechanism involving miR-181c and TRIM2 in the cognitive impairment induced by CCH and provided a rationale for the development of miRNA-based strategies for prevention of dementia.
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Affiliation(s)
- Chen Fang
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, 10 Xi Tou Tiao, You An Men street, Beijing, 100069, China
| | - Qian Li
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, 10 Xi Tou Tiao, You An Men street, Beijing, 100069, China
| | - Guowen Min
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, 10 Xi Tou Tiao, You An Men street, Beijing, 100069, China
| | - Min Liu
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, 10 Xi Tou Tiao, You An Men street, Beijing, 100069, China
| | - Jing Cui
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, 10 Xi Tou Tiao, You An Men street, Beijing, 100069, China
| | - Jing Sun
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, 10 Xi Tou Tiao, You An Men street, Beijing, 100069, China
| | - Liang Li
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, 10 Xi Tou Tiao, You An Men street, Beijing, 100069, China.
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Behavioral and biochemical evidences for nootropic activity of boldine in young and aged mice. Biomed Pharmacother 2017; 97:895-904. [PMID: 29136766 DOI: 10.1016/j.biopha.2017.11.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 10/28/2017] [Accepted: 11/03/2017] [Indexed: 12/15/2022] Open
Abstract
Boldine, a bioactive compound, has been reported to be neuroprotective, but its effect on learning and memory has not been explored. So, the present study was aimed to study the effect of boldine on the learning and memory of the Swiss albino male young and aged mice. Boldine (1.5, 3 and 6mg/kg, po) and physostigmine salicylate (0.1mg/kg, ip) were administered to separate groups of mice for 7 successive days. Morris water maze was utilized as a behavioural model to study the effect of drugs on learning and memory of mice. Boldine and physostigmine significantly improved learning and memory of young as well as aged mice, as indicated by decrease in escape latency time during training session and increase in time spent in target quadrant during retrieval session. No significant effect on locomotor activities of mice was observed due to drug treatments. Memory-enhancing activity of boldine (3mg/kg) was found to be comparable to physostigmine. Boldine significantly reversed scopolamine-, sodium nitrite- and aging-induced amnesia in mice. Moreover, boldine attenuated oxidative stress, as shown by a significant decrease in brain malondialdehyde as well as brain nitrite levels and a significant increase in brain GSH level of young as well as aged mice. Brain acetylcholinesterase activity was also significantly inhibited by boldine in young as well as aged mice. In conclusion boldine administered for 7 successive days exhibited significant improvement of learning and memory of young and aged mice possibly through inhibition of brain acetylcholinesterase activity and alleviation of brain oxidative stress.
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Fedorovich S, Hofmeijer J, van Putten MJAM, le Feber J. Reduced Synaptic Vesicle Recycling during Hypoxia in Cultured Cortical Neurons. Front Cell Neurosci 2017; 11:32. [PMID: 28261063 PMCID: PMC5311063 DOI: 10.3389/fncel.2017.00032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/01/2017] [Indexed: 01/08/2023] Open
Abstract
Improvement of neuronal recovery in the ischemic penumbra, an area around the core of a brain infarct with some remaining perfusion, has a large potential for the development of therapy against acute ischemic stroke. However, mechanisms that lead to either recovery or secondary damage in the penumbra largely remain unclear. Recent studies in cultured networks of cortical neurons showed that failure of synaptic transmission (referred to as synaptic failure) is a critical factor in the penumbral area, but the mechanisms that lead to synaptic failure are still under investigation. Here we used a Styryl dye, FM1-43, to quantify endocytosis and exocytosis in cultures of rat cortical neurons under normoxic and hypoxic conditions. Hypoxia in cultured cortical networks rapidly depressed endocytosis and, to a lesser extent, exocytosis. These findings support electrophysiological findings that synaptic failure occurs quickly after the induction of hypoxia, and confirms that the failing processes are at least in part presynaptic.
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Affiliation(s)
- Sergei Fedorovich
- Laboratory of Biophysics and Cellular Engineering, Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus Minsk, Belarus
| | - Jeannette Hofmeijer
- Clinical Neurophysiology, University of TwenteEnschede, Netherlands; Department of Neurology, Rijnstate HospitalArnhem, Netherlands
| | - Michel J A M van Putten
- Clinical Neurophysiology, University of TwenteEnschede, Netherlands; Department of Neurology and Clinical Neurophysiology, Medisch Spectrum TwenteEnschede, Netherlands
| | - Joost le Feber
- Clinical Neurophysiology, University of Twente Enschede, Netherlands
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Raised Intracellular Calcium Contributes to Ischemia-Induced Depression of Evoked Synaptic Transmission. PLoS One 2016; 11:e0148110. [PMID: 26934214 PMCID: PMC4775070 DOI: 10.1371/journal.pone.0148110] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/13/2016] [Indexed: 12/26/2022] Open
Abstract
Oxygen-glucose deprivation (OGD) leads to depression of evoked synaptic transmission, for which the mechanisms remain unclear. We hypothesized that increased presynaptic [Ca2+]i during transient OGD contributes to the depression of evoked field excitatory postsynaptic potentials (fEPSPs). Additionally, we hypothesized that increased buffering of intracellular calcium would shorten electrophysiological recovery after transient ischemia. Mouse hippocampal slices were exposed to 2 to 8 min of OGD. fEPSPs evoked by Schaffer collateral stimulation were recorded in the stratum radiatum, and whole cell current or voltage clamp recordings were performed in CA1 neurons. Transient ischemia led to increased presynaptic [Ca2+]i, (shown by calcium imaging), increased spontaneous miniature EPSP/Cs, and depressed evoked fEPSPs, partially mediated by adenosine. Buffering of intracellular Ca2+ during OGD by membrane-permeant chelators (BAPTA-AM or EGTA-AM) partially prevented fEPSP depression and promoted faster electrophysiological recovery when the OGD challenge was stopped. The blocker of BK channels, charybdotoxin (ChTX), also prevented fEPSP depression, but did not accelerate post-ischemic recovery. These results suggest that OGD leads to elevated presynaptic [Ca2+]i, which reduces evoked transmitter release; this effect can be reversed by increased intracellular Ca2+ buffering which also speeds recovery.
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Stoyanova II, Hofmeijer J, van Putten MJAM, le Feber J. Acyl Ghrelin Improves Synapse Recovery in an In Vitro Model of Postanoxic Encephalopathy. Mol Neurobiol 2015; 53:6136-6143. [PMID: 26541885 PMCID: PMC5085991 DOI: 10.1007/s12035-015-9502-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/19/2015] [Indexed: 11/04/2022]
Abstract
Comatose patients after cardiac arrest have a poor prognosis. Approximately half never awakes as a result of severe diffuse postanoxic encephalopathy. Several neuroprotective agents have been tested, however without significant effect. In the present study, we used cultured neuronal networks as a model system to study the general synaptic damage caused by temporary severe hypoxia and the possibility to restrict it by ghrelin treatment. Briefly, we applied hypoxia (pO2 lowered from 150 to 20 mmHg) during 6 h in 55 cultures. Three hours after restoration of normoxia, half of the cultures were treated with ghrelin for 24 h, while the other, non-supplemented, were used as a control. All cultures were processed immunocytochemically for detection of the synaptic marker synaptophysin. We observed that hypoxia led to drastic decline of the number of synapses, followed by some recovery after return to normoxia, but still below the prehypoxic level. Additionally, synaptic vulnerability was selective: large- and small-sized neurons were more susceptible to synaptic damage than the medium-sized ones. Ghrelin treatment significantly increased the synapse density, as compared with the non-treated controls or with the prehypoxic period. The effect was detected in all neuronal subtypes. In conclusion, exogenous ghrelin has a robust impact on the recovery of cortical synapses after hypoxia. It raises the possibility that ghrelin or its analogs may have a therapeutic potential for treatment of postanoxic encephalopathy.
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Affiliation(s)
- Irina I Stoyanova
- Department of Clinical Neurophysiology, Faculty of Science and Technology, University of Twente, Building Carré 3714, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
| | - Jeannette Hofmeijer
- Department of Clinical Neurophysiology, Faculty of Science and Technology, University of Twente, Building Carré 3714, P.O. Box 217, 7500 AE, Enschede, The Netherlands.,Department of Neurology, Rijnstate Hospital, Arnhem, The Netherlands
| | - Michel J A M van Putten
- Department of Clinical Neurophysiology, Faculty of Science and Technology, University of Twente, Building Carré 3714, P.O. Box 217, 7500 AE, Enschede, The Netherlands.,Department of Clinical Neurophysiology, Medisch Spectrum Twente, Enschede, The Netherlands
| | - Joost le Feber
- Department of Clinical Neurophysiology, Faculty of Science and Technology, University of Twente, Building Carré 3714, P.O. Box 217, 7500 AE, Enschede, The Netherlands.,Department of Biomedical Signals and Systems, EWI, University of Twente, Enschede, The Netherlands
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18
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Daulatzai MA. Evidence of neurodegeneration in obstructive sleep apnea: Relationship between obstructive sleep apnea and cognitive dysfunction in the elderly. J Neurosci Res 2015; 93:1778-94. [DOI: 10.1002/jnr.23634] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/02/2015] [Accepted: 08/04/2015] [Indexed: 02/06/2023]
Affiliation(s)
- Mak Adam Daulatzai
- Sleep Disorders Group, EEE/Melbourne School of Engineering, The University of Melbourne; Parkville Victoria Australia
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Daulatzai MA. “Boomerang Neuropathology” of Late-Onset Alzheimer’s Disease is Shrouded in Harmful “BDDS”: Breathing, Diet, Drinking, and Sleep During Aging. Neurotox Res 2015; 28:55-93. [DOI: 10.1007/s12640-015-9528-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Revised: 04/03/2015] [Accepted: 04/03/2015] [Indexed: 12/12/2022]
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Neuroligin-associated microRNA-932 targets actin and regulates memory in the honeybee. Nat Commun 2014; 5:5529. [PMID: 25409902 DOI: 10.1038/ncomms6529] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/10/2014] [Indexed: 02/06/2023] Open
Abstract
Increasing evidence suggests small non-coding RNAs (ncRNAs) such as microRNAs (miRNAs) control levels of mRNA expression during experience-related remodelling of the brain. Here we use an associative olfactory learning paradigm in the honeybee Apis mellifera to examine gene expression changes in the brain during memory formation. Brain transcriptome analysis reveals a general downregulation of protein-coding genes, including asparagine synthetase and actin, and upregulation of ncRNAs. miRNA-mRNA network predictions together with PCR validation suggest miRNAs including miR-210 and miR-932 target the downregulated protein-coding genes. Feeding cholesterol-conjugated antisense RNA to bees results in the inhibition of miR-210 and of miR-932. Loss of miR-932 impairs long-term memory formation, but not memory acquisition. Functional analyses show that miR-932 interacts with Act5C, providing evidence for direct regulation of actin expression by an miRNA. An activity-dependent increase in miR-932 expression may therefore control actin-related plasticity mechanisms and affect memory formation in the brain.
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Wu X, Sun J, Zhang X, Li X, Liu Z, Yang Q, Li L. Epigenetic Signature of Chronic Cerebral Hypoperfusion and Beneficial Effects of S-adenosylmethionine in Rats. Mol Neurobiol 2014; 50:839-51. [DOI: 10.1007/s12035-014-8698-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 03/24/2014] [Indexed: 11/27/2022]
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Hofmeijer J, Mulder AT, Farinha AC, van Putten MJ, le Feber J. Mild hypoxia affects synaptic connectivity in cultured neuronal networks. Brain Res 2014; 1557:180-9. [DOI: 10.1016/j.brainres.2014.02.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/18/2013] [Accepted: 02/12/2014] [Indexed: 10/25/2022]
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23
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Tjepkema-Cloostermans MC, Hindriks R, Hofmeijer J, van Putten MJ. Generalized periodic discharges after acute cerebral ischemia: Reflection of selective synaptic failure? Clin Neurophysiol 2014; 125:255-62. [PMID: 24012049 DOI: 10.1016/j.clinph.2013.08.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 07/08/2013] [Accepted: 08/05/2013] [Indexed: 10/26/2022]
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Vollert C, Forkuo GS, Bond RA, Eriksen JL. Chronic treatment with DCPCX, an adenosine A(1) antagonist, worsens long-term memory. Neurosci Lett 2013; 548:296-300. [PMID: 23748072 DOI: 10.1016/j.neulet.2013.05.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/07/2013] [Accepted: 05/18/2013] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease is characterized by progressive cognitive disturbances and neurotransmitter dysfunction. Previous studies targeting the adrenergic A1 pathway suggest that this plays a role in cognitive impairment in Alzheimer's disease. Previous studies have reported that acute treatment with A1 antagonists appears to improve behavioral deficits in rodent models of memory and behavioral impairment. In this study, we addressed whether the chronic administration of 8-cyclopentyl-1,3-dipropylxanthine, a potent and selective adenosine A1 antagonist, could reverse the memory deficits found in aged APPswe/PS1dE9 mice. Chronic treatment did not improve memory in the APPswe/PS1dE9 mouse model and resulted in reduced exploratory behavior, suggestive of reduced anxiety, and a worsening of long-term memory in nontransgenic mice. These results have important implications for understanding the mechanisms of A1 receptor modulation as a target in Alzheimer's disease therapy.
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Affiliation(s)
- Craig Vollert
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, USA
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25
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Death by a thousand cuts in Alzheimer's disease: hypoxia--the prodrome. Neurotox Res 2013; 24:216-43. [PMID: 23400634 DOI: 10.1007/s12640-013-9379-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 01/10/2013] [Accepted: 01/21/2013] [Indexed: 12/30/2022]
Abstract
A wide range of clinical consequences may be associated with obstructive sleep apnea (OSA) including systemic hypertension, cardiovascular disease, pulmonary hypertension, congestive heart failure, cerebrovascular disease, glucose intolerance, impotence, gastroesophageal reflux, and obesity, to name a few. Despite this, 82 % of men and 93 % of women with OSA remain undiagnosed. OSA affects many body systems, and induces major alterations in metabolic, autonomic, and cerebral functions. Typically, OSA is characterized by recurrent chronic intermittent hypoxia (CIH), hypercapnia, hypoventilation, sleep fragmentation, peripheral and central inflammation, cerebral hypoperfusion, and cerebral glucose hypometabolism. Upregulation of oxidative stress in OSA plays an important pathogenic role in the milieu of hypoxia-induced cerebral and cardiovascular dysfunctions. Strong evidence underscores that cerebral amyloidogenesis and tau phosphorylation--two cardinal features of Alzheimer's disease (AD), are triggered by hypoxia. Mice subjected to hypoxic conditions unambiguously demonstrated upregulation in cerebral amyloid plaque formation and tau phosphorylation, as well as memory deficit. Hypoxia triggers neuronal degeneration and axonal dysfunction in both cortex and brainstem. Consequently, neurocognitive impairment in apneic/hypoxic patients is attributable to a complex interplay between CIH and stimulation of several pathological trajectories. The framework presented here helps delineate the emergence and progression of cognitive decline, and may yield insight into AD neuropathogenesis. The global impact of CIH should provide a strong rationale for treating OSA and snoring clinically, in order to ameliorate neurocognitive impairment in aged/AD patients.
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López-Pérez S, Morales-Villagrán A, Ventura-Valenzuela J, Medina-Ceja L. Short- and long-term changes in extracellular glutamate and acetylcholine concentrations in the rat hippocampus following hypoxia. Neurochem Int 2012; 61:258-65. [DOI: 10.1016/j.neuint.2012.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 02/08/2012] [Accepted: 03/13/2012] [Indexed: 01/25/2023]
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27
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Baclofen influences acquisition and MMP-2, MMP-9 levels in the hippocampus of rats after hypoxia. Pharmacol Rep 2012; 64:536-45. [DOI: 10.1016/s1734-1140(12)70849-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 02/02/2012] [Indexed: 11/18/2022]
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Abstract
In the human brain, ≈30% of the energy is spent on synaptic transmission. Disappearance of synaptic activity is the earliest consequence of cerebral ischemia. The changes of synaptic function are generally assumed to be reversible and persistent damage is associated with membrane failure and neuronal death. However, there is overwhelming experimental evidence of isolated, but persistent, synaptic failure resulting from mild or moderate cerebral ischemia. Early failure results from presynaptic damage with impaired transmitter release. Proposed mechanisms include dysfunction of adenosine triphosphate-dependent calcium channels and a disturbed docking of glutamate-containing vesicles resulting from impaired phosphorylation. We review energy distribution among neuronal functions, focusing on energy usage of synaptic transmission. We summarize the effect of ischemia on neurotransmission and the evidence of long-lasting synaptic failure as a cause of persistent symptoms in patients with cerebral ischemia. Finally, we discuss the implications of synaptic failure in the diagnosis of cerebral ischemia, including the limited sensitivity of diffusion-weighted MRI in those cases in which damage is presumably limited to the synapses.
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Affiliation(s)
- Jeannette Hofmeijer
- Department of Neurology, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, The Netherlands.
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29
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Levin SG, Godukhin OV. Anti-inflammatory cytokines, TGF-β1 and IL-10, exert anti-hypoxic action and abolish posthypoxic hyperexcitability in hippocampal slice neurons: comparative aspects. Exp Neurol 2011; 232:329-32. [PMID: 21945008 DOI: 10.1016/j.expneurol.2011.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 08/30/2011] [Accepted: 09/05/2011] [Indexed: 10/17/2022]
Abstract
The aim of this study was to investigate the comparative effects of transforming growth factor β1 (TGF-β1) and interleukin-10 (IL-10) on the repeated brief hypoxia-induced alterations in the activity of hippocampal slice CA1 pyramidal neurons. The method of field potentials measurement in CA1 region of hippocampal slices was used. The principal results of our work are summarized as follow. 1. TGF-β1 reduces the depressive effect of brief hypoxia on the population spike amplitude more effectively than IL-10. 2. During TGF-β1 exposure (in contrast to IL-10), three 3-min hypoxic episodes do not induce the rapid hypoxic preconditioning. 3. TGF-β1 and IL-10 equally abolish posthypoxic hyperexcitability induced by repeated brief episodes of hypoxia in CA1 pyramidal neurons. These findings indicated that TGF-β1 and IL-10 are able to evoke anti-hypoxic effect and abolish the development of posthypoxic hyperexcitability induced by repeated brief hypoxic episodes in hippocampal CA1 pyramidal neurons. Our results also demonstrated that TGF-β1 reduced the effectiveness of hypoxia to depress neuronal activity more effectively than IL-10. We suggest that the present findings allow to explain the certain neuroprotective mechanisms of IL-10 and TGF-beta1 in the early phase of hypoxia and indicate that a therapeutic anti-inflammatory approach using these substances can provide neuroprotection in the brain hypoxic conditions.
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Affiliation(s)
- Sergei G Levin
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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30
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Liu H, Xing A, Wang X, Liu G, Li L. Regulation of β-amyloid level in the brain of rats with cerebrovascular hypoperfusion. Neurobiol Aging 2011; 33:826.e31-42. [PMID: 21813211 DOI: 10.1016/j.neurobiolaging.2011.05.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 05/11/2011] [Accepted: 05/15/2011] [Indexed: 10/17/2022]
Abstract
Cerebrovascular hypoperfusion occurs prior to clinical symptoms of Alzheimer's disease (AD) and represents the most accurate indicator predicting whether an individual develops AD in a future time. In order to explore the contribution of cerebrovascular hypoperfusion to AD, cerebrovascular hypoperfusion induced by bilateral carotid occlusion surgery in adult rats was used to investigate its impacts on spatial memory, amyloid-β protein (Aβ) production and clearance in the brain. The progressive spatial memory deficits were observed through Morris water maze test of the rats with cerebrovascular hypoperfusion induced by occlusion surgery. The memory deficits were accompanied with the increase of brain Aβ associated with Aβ overproduction due to the increased expression of β-amyloid precursor protein (APP) and enhanced activities of amyloid precursor protein cleavage enzymes such as β- and γ-secretases. Western blot and immunohistochemisty studies further revealed that cerebrovascular hypoperfusion could induce abnormal expression of β-amyloid receptor proteins including the receptor for advanced glycation end products (RAGE) and low-density lipoprotein receptor-related protein-1 (LRP-1), and result in a shift of immunoreactivity between neurons and vasculatures. Taken together, our results suggested that chronic cerebrovascular hypoperfusion could cause memory impairment and Aβ accumulation in brain associated with increased generation and impaired clearance of Aβ. Cerebrovascular hypoperfusion plays an important role in the pathogenesis and development of AD.
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Affiliation(s)
- Hong Liu
- Department of Pathology, Capital Medical University, Beijing, China
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31
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Abstract
Recent experiments in rats have shown the occurrence of a high amplitude slow brain wave in the EEG approximately 1 minute after decapitation, with a duration of 5-15 s (van Rijn et al, PLoS One 6, e16514, 2011) that was presumed to signify the death of brain neurons. We present a computational model of a single neuron and its intra- and extracellular ion concentrations, which shows the physiological mechanism for this observation. The wave is caused by membrane potential oscillations, that occur after the cessation of activity of the sodium-potassium pumps has lead to an excess of extracellular potassium. These oscillations can be described by the Hodgkin-Huxley equations for the sodium and potassium channels, and result in a sudden change in mean membrane voltage. In combination with a high-pass filter, this sudden depolarization leads to a wave in the EEG. We discuss that this process is not necessarily irreversible.
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Fung SJ, Xi MC, Zhang JH, Yamuy J, Sampogna S, Tsai KL, Lim V, Morales FR, Chase MH. Eszopiclone prevents excitotoxicity and neurodegeneration in the hippocampus induced by experimental apnea. Sleep 2010; 32:1593-601. [PMID: 20041595 DOI: 10.1093/sleep/32.12.1593] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
STUDY OBJECTIVE This study was designed to determine the effects of eszopiclone on apnea-induced excitotoxic synaptic processes and apoptosis in the hippocampus. DESIGN Recurrent periods of apnea, which consisted of a sequence of apnea (75% SpO2), followed by ventilation with recovery to normoxia (> 95% SpO2), were induced for a period of three hours in anesthetized guinea pigs. The CA3 Schaffer collateral pathway in the hippocampus was stimulated and the field excitatory postsynaptic potential (fEPSP) response was recorded in CA1. Animals in the experimental group received an intravenous injection of eszopiclone (3 mg/kg) 10 min prior to the initiation of the periods of recurrent apnea, and once every 60 min thereafter; control animals received comparable injections of vehicle. At the end of the 3-h period of recurrent apnea, the animals were perfused, and hippocampal sections were immunostained in order to determine the presence of apoptosis, i.e., programmed cell death. ANALYSES AND RESULTS: Apnea resulted in a persistent increase in synaptic responsiveness of CA1 neurons as determined by analyses of the fEPSP. Eszopiclone antagonized the apnea-induced increase in the fEPSP. Morphological analyses revealed significant apoptosis of CA1 neurons in control animals; however, there was no significant apoptosis in eszopiclone-treated animals. CONCLUSIONS Eszopiclone was determined to suppress the apnea-induced hyperexcitability of hippocampal CA1 neurons, thereby reducing/eliminating neurotoxicity. These data lend credence to our hypothesis that eszopiclone, exclusive of its hypnotic actions, has the capacity to function as a potent neuroprotective agent.
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Affiliation(s)
- Simon J Fung
- WebSciences International, 1251 Westwood Blvd., Los Angeles, CA 90024, USA.
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33
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Spatial learning and memory deficits following exposure to 24 h of sleep fragmentation or intermittent hypoxia in a rat model of obstructive sleep apnea. Brain Res 2009; 1294:128-37. [PMID: 19643093 DOI: 10.1016/j.brainres.2009.07.064] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 07/13/2009] [Accepted: 07/18/2009] [Indexed: 01/02/2023]
Abstract
Obstructive sleep apnea is primarily characterized by hypoxemia due to frequent apneic episodes and fragmentation of sleep due to the brief arousals that terminate the apneic episodes. Though neurobehavioral deficits frequently accompany sleep apnea, the relative roles of hypoxia versus sleep fragmentation are difficult to separate in apneic patients. Here, we assessed cognitive function as measured by water maze in the Fischer/Brown Norway (FBN) rat, comparing 24 h of sleep interruption (SI) to 24 h of intermittent hypoxia (IH), in order to dissociate their relative contributions to cognitive impairment. For SI, automated treadmills were used to induce brief ambulation in rats every 2 min, either prior to, or after, initial water maze acquisition training. IH was simulated by cycling environmental oxygen levels between 6% and 19% every 2 min, again either prior to, or after, acquisition. Twenty-four hours of IH exposure had no significant effect on either acquisition or retention, irrespective of whether IH occurred prior to, or after, acquisition. To replicate previous work, another group of rats, exposed to 3 days of IH (10 h/day) prior to acquisition, had impaired performance during acquisition. A comparison of the 24 h IH and 3 day IH findings suggests that a minimum amount of IH exposure is necessary to produce detectable spatial memory impairments. Although SI before acquisition had no effect on acquisition or later retention of the hidden platform location, SI after acquisition robustly impaired retention, indicating that spatial memory consolidation is more susceptible to the effects of sleep disruption than is the acquisition (learning) of spatial information.
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Zhang JH, Fung SJ, Xi M, Sampogna S, Chase MH. Recurrent apnea induces neuronal apoptosis in the guinea pig forebrain. Exp Neurol 2008; 216:290-4. [PMID: 19124019 DOI: 10.1016/j.expneurol.2008.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 12/01/2008] [Indexed: 11/29/2022]
Abstract
Obstructive sleep apnea (OSA) and sleep-disordered breathing (SDB) can result in impaired cognition and mental acuity, and the generation of mood disorders, including depression. However, the mechanisms of neuronal damage for these complications have not been elucidated. Accordingly, using immunohistochemical technique with monoclonal antibody against single-stranded DNA, we examined the morphological effects of chronic recurrent apnea on neurons in the hippocampus and related forebrain sites in guinea pigs. Our results show that a large number of neurons labeled by anti-ssDNA antibody were present in the cingulate, insular and frontal cortices, the hippocampus and the amygdala in conjunction with periods of recurrent apnea. However, no labeling was observed in comparable regions of the brain in control guinea pigs. In the cortices of experimental animals, labeled neurons were detected mainly in the superficial layers (II-III) in the frontal, insular and cingulate cortex. In the hippocampus, most labeled neurons were located in the CA1 region, in which most of stained neurons were observed in strata pyramidal, while only a few positive neurons were located in the strata radiatum and the strata oriens. In addition, a large number of labeled neurons were also detected in the central nucleus of amygdala in the guinea pigs underwent recurrent periods of apnea. The present data indicate that recurrent apnea results in cell death in the hippocampus and related forebrain regions via mechanisms of apoptosis, which may represent the basis for the clinical complications of obstructive sleep apnea and sleep-disordered breathing.
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Bekker A, Haile M, Gingrich K, Wenning L, Gorny A, Quartermain D, Blanck T. Physostigmine Reverses Cognitive Dysfunction Caused by Moderate Hypoxia in Adult Mice. Anesth Analg 2007; 105:739-43. [PMID: 17717233 DOI: 10.1213/01.ane.0000265555.57472.49] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Cognitive changes associated with moderate hypoxia in rodents may result from the diminished functioning of central cholinergic neurotransmission. We designed this study to examine whether treatment with physostigmine (PHY), an acetylcholinesterase inhibitor, could improve the impairment of working memory after hypoxic hypoxia. METHODS We randomized 90 Swiss Webster, 30-35 g mice (6-8 wks) to three hypoxia groups at fraction of inspired oxygen, FiO2 = 0.10 (1. no treatment; 2. PHY 0.1 mg/kg intraperitoneally administered immediately before; or 3. after hypoxia), or to two room air groups (given either no treatment or PHY after an insult). An object recognition test was used to assess short-term memory function. The object recognition test exploits the tendency of mice to prefer exploring novel objects in an environment when a familiar object is also present. During the 15 min training trial, two identical objects were placed in two defined sites of the box. During the test trial performed 1 h later, one of the objects was replaced by a new object with a different shape. The time spent exploring the two objects was automatically recorded by a video camera and associated software. The performance was analyzed with ANOVA, followed by post hoc comparisons using the Newman-Keuls test when appropriate. P values <0.05 were considered significant. RESULTS Untreated mice subjected to hypoxia at Fio2 = 0.1 spent significantly less time exploring a novel object on testing day 1 than did untreated mice breathing room air. Performance of the mice subjected to hypoxia, who received physostigmine after, but not before, the insult did not differ from the control group. CONCLUSION Moderate hypoxia impairs rodents' performance in a working memory task. It appears that changes are transient, because the cognitive functioning of the mice returned to the baseline level 7 days after treatment. Postinsult administration of PHY prevented deterioration of cognitive function. An increased level of acetylcholine in the central nervous system may be responsible for the improved performance of the hypoxia-treated mice.
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Affiliation(s)
- Alex Bekker
- Department of Anesthesiology, New York University Medical Center, New York, NY 10016, USA.
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Fung SJ, Xi MC, Zhang JH, Sampogna S, Yamuy J, Morales FR, Chase MH. Apnea promotes glutamate-induced excitotoxicity in hippocampal neurons. Brain Res 2007; 1179:42-50. [PMID: 17888415 PMCID: PMC3169175 DOI: 10.1016/j.brainres.2007.08.044] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Revised: 08/13/2007] [Accepted: 08/18/2007] [Indexed: 10/22/2022]
Abstract
Patients with obstructive sleep apnea (OSA) exhibit hippocampal damage and cognitive deficits. To determine the effect of apnea on the synaptic transmission in the hippocampus, we performed electrophysiological studies in an in vivo guinea pig model of OSA. Specifically, we determined the cornu ammonis region 1 (CA1) field excitatory postsynaptic potential (fEPSP) response to cornu ammonis region 3 (CA3) stimulation and examined the presynaptic mechanisms underlying the changes in the fEPSP. Single episodes of apnea resulted in a maximal potentiation of the fEPSPs at 1 to 3 min after the termination of each episode of apnea. The mean amplitude and slope of the post-apneic fEPSP was significantly larger compared with the pre-apneic control. These changes were accompanied by a significant decrease in the paired-pulse facilitation ratio during the post-apneic period compared with the pre-apneic control. The N-methyl-D-aspartate (NMDA) glutamate receptor antagonist MK-801, when applied locally to the CA1 recording site by pressure ejection, blocked the apnea-induced potentiation of the fEPSP. In the experimental animals that were subjected to extended periods of recurrent apnea, CA1 neurons exhibited positive immunoreactivity for fragmented DNA strands, which indicates apoptotic cell death. The present results demonstrate that apnea-induced potentiation of the hippocampal CA1 fEPSP is mediated by an NMDA receptor mechanism. We therefore conclude that recurrent apnea produces abnormally high levels of glutamate that results in the apoptosis of CA1 neurons. We hypothesize that this damage is reflected by the cognitive deficits that are commonly observed in patients with breathing disorders such as OSA.
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Affiliation(s)
- Simon J Fung
- WebSciences International, 1251 Westwood Blvd., Los Angeles, CA 90024, USA.
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Sheng Z, Dai Q, Prorok M, Castellino FJ. Subtype-selective antagonism of N-methyl-D-aspartate receptor ion channels by synthetic conantokin peptides. Neuropharmacology 2007; 53:145-56. [PMID: 17588620 PMCID: PMC3965200 DOI: 10.1016/j.neuropharm.2007.04.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 03/28/2007] [Accepted: 04/25/2007] [Indexed: 01/29/2023]
Abstract
Conantokin-G (con-G), conantokin-T (con-T), a truncated conantokin-R (con-R[1-17]), that functions the same as wild-type con-R, and variant sequences of con-T, were chemically synthesized and employed to investigate their selectivities as antagonists of glutamate/glycine-evoked ion currents in human embryonic kidney-293 cells expressing various combinations of NMDA receptor (NMDAR) subunits (NR), viz., NR1a/2A, NR1a/2B, NR1b/2A and NR1b/2B. Con-G did not substantially affect ion flow into NR1a,b/NR2A-transfected cells, but potently inhibited cells expressing NR1a,b/NR2B, showing high NR2B selectivity. Con-T and con-R served as non-selective antagonists of all of four NMDAR subunit combinations. C-terminal truncation variants of the 21-residue con-T were synthesized and examined in this regard. While NMDAR ion channel antagonist activity, and the ability to adopt the Ca(2+)-induced alpha-helical conformation, diminished as a function of shortening the COOH-terminus of con-T, NMDAR subtype selectivity was enhanced in the con-T[1-11], con-T[1-9], and con-T[1-8] variants toward NR2A, NR1b, and NR1b/2A, respectively. Receptor subtype selectivity was also obtained with Met-8 sequence variants of con-T. Con-T[M8A] and con-T[M8Q] displayed selectivity with NR2B-containing subunits, while con-T[M8E] showed enhanced activity toward NR1b-containing NMDAR subtypes. Of those studied, the most highly selective variant was con-T[M8I], which showed maximal NMDAR ion channel antagonism activity toward the NR1a/2A subtype. These studies demonstrate that it is possible to engineer NMDAR subtype antagonist specificity into con-T. Since the subunit composition of the NMDAR varies temporally and spatially in developing brain and in various disease states, conantokins with high subtype selectivities are potentially valuable drugs that may be used at specific stages of disease and in selected regions of the brain.
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Affiliation(s)
- Zhenyu Sheng
- W.M. Keck Center for Transgene Research, 230 Raclin-Carmichael Hall, University of Notre Dame, Notre Dame, IN 46556, USA
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Sun MK, Alkon DL. Protein kinase C substrate activators: potential as novel antidepressants. Drug Dev Res 2005. [DOI: 10.1002/ddr.20019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bruggemans EF, van Boxtel A, Huysmans HA. INVITED COMMENTARY. Ann Thorac Surg 2005. [DOI: 10.1016/j.athoracsur.2004.07.082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
While it is generally accepted that cognitive processes such as learning and memory are affected by emotion, the impact of depression on learning and memory has rarely been directly studied in experimental animals. Effects of induced depressive behavior on learning and memory were determined in rats, using an open space swim test, a novel animal model of depressive behavior that is developed recently in our laboratory. The model indexes searching activity of the animals, with the induced depressive immobility behavior showing specific sensitivity to three major prototypic classes of antidepressants and a selective serotonin reuptake inhibitor. The induced depressive behavior in rats showed a delayed response to chronic antidepressant treatment and had a lasting effect on the ability of rats to learn and recall the learned experience. It impaired the subsequent ability of rats to learn and recall both a spatial water maze task and a multi-trial passive avoidance task. These impairments were all sensitive to antidepressant therapeutics, but not to buspirone, an anxiolytic. By way of contrast, the ability of the rats to sense and move to a visible platform and to escape from an unconditioned shock stimulus was neither impaired by inducing the depressive behavior nor altered by the drug treatment, suggesting that non-specific changes in sensorimotor ability were not involved. These impairments of learning and memory indicate that the depressive behavior-induced deficits show generalizability and are not context-limited. This animal model of depressive behavior shows promising potential as a screen for novel antidepressive therapeutics and as a disease model for revealing network/cellular/molecular mechanisms in the pathophysiology of depression and depression-induced cognitive deficits.
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Affiliation(s)
- M-K Sun
- Blanchette Rockefeller Neurosciences Institute, 9601 Medical Center Drive, Johns Hopkins Academic and Research Building, Room 319, Rockville, MD 20850, USA.
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Abstract
Depression is characterized by a lack of "motivation" rather than a lack of "physical space" to move around. This study was designed to evaluate predictivity of an open space swimming test for antidepressant activity of various antidepressants in rats. Without drug treatment, rats showed a significant reduction in the distance moved (increased immobility) over successive trials in an open space water pool. Three major classes of antidepressants and a selective serotonin reuptake inhibitor (SSRI) were tested. Repeated treatment (10 mg/kg x 3 per day) of imipramine, a prototypical tricyclic antidepressant, iproniazid, a monoamine oxidase inhibitor, mianserin, an atypical antidepressant, and alaproclate, an SSRI, all significantly reduced the immobility. These results suggest that the open space swimming test is highly predictive of antidepressant action and is more sensitive to the drug treatments. The measurement is more objective than that of the forced swimming test and does not involve judging and scoring the animals' movement or lack of movement by investigators. The demonstrated effectiveness of three major types of antidepressants and an SSRI suggests that the effects on the test are not restricted to a particular underlying molecular mechanism of action. Thus, this swimming test shows promising potential as a screen for novel antidepressants and, perhaps, for revealing some of the underlying pathophysiology of depression.
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Affiliation(s)
- Miao-Kun Sun
- Blanchette Rockefeller Neurosciences Institute, West Virginia University, 9601 Medical Center Dr., Johns Hopkins Academic and Research Bldg., Room 319, Rockville, MD 20850, USA.
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Ribeiro JA, Sebastião AM, de Mendonça A. Adenosine receptors in the nervous system: pathophysiological implications. Prog Neurobiol 2002; 68:377-92. [PMID: 12576292 DOI: 10.1016/s0301-0082(02)00155-7] [Citation(s) in RCA: 374] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adenosine is a ubiquitous homeostatic substance released from most cells, including neurones and glia. Once in the extracellular space, adenosine modifies cell functioning by operating G-protein-coupled receptors (GPCR; A(1), A(2A), A(2B), A(3)) that can inhibit (A(1)) or enhance (A(2)) neuronal communication. Interactions between adenosine receptors and other G-protein-coupled receptors, ionotropic receptors and receptors for neurotrophins also occur, and this might contribute to a fine-tuning of neuronal function. Manipulations of adenosine receptors influence sleep and arousal, cognition and memory, neuronal damage and degeneration, as well as neuronal maturation. These actions might have therapeutic implications for neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, as well as for other neurological situations such as epilepsy, idiopathic pain or even drug addition. Peripheral side effects associated with adenosine receptor agonists limit their usefulness in therapeutics; in contrast, adenosine receptor antagonists appear to have less side effects as it is the case of the well-known non-selective antagonists theophylline (present in tea) or caffeine (abundant in coffee and tea), and their emerging beneficial actions in Parkinson's disease and Alzheimer's disease are encouraging. A(1) receptor antagonism may also be useful to enhance cognition and facilitate arousal, as well as in the periphery when deficits of neurotransmitter release occur (e.g. myasthenic syndromes). Enhancement of extracellular adenosine levels through drugs that influence its metabolism might prove useful approaches in situations such as neuropathic pain, where enhanced activation of inhibitory adenosine A(1) receptors is beneficial. One might then consider adenosine as a fine-tuning modulator of neuronal activity, which via subtle effects causes harmonic actions on neuronal activity. Whenever this homeostasis is disrupted, pathology may be installed and selective receptor antagonism or agonism required.
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Affiliation(s)
- J A Ribeiro
- Laboratory of Neurosciences, Faculty of Medicine, Institute for Molecular Medicine, University of Lisbon, Lisbon, Portugal.
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